|blackBoxWarningTitle=<span style="color:#FF0000;">WARNING: SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE & APLASTIC ANEMIA AND AGRANULOCYTOSIS</span>
| PubChem = 2554
|blackBoxWarningBody=<i><span style="color:#FF0000;">SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE: </span></i>
| DrugBank = APRD00337
| C=15 | H=12 | N=2 | O=1
* SERIOUS AND SOMETIMES FATAL DERMATOLOGIC REACTIONS, INCLUDING TOXIC EPIDERMAL NECROLYSIS (TEN) AND STEVENS-JOHNSON SYNDROME (SJS), HAVE BEEN REPORTED DURING TREATMENT WITH TEGRETOL. THESE REACTIONS ARE ESTIMATED TO OCCUR IN 1 TO 6 PER 10,000 NEW USERS IN COUNTRIES WITH MAINLY CAUCASIAN POPULATIONS, BUT THE RISK IN SOME ASIAN COUNTRIES IS ESTIMATED TO BE ABOUT 10 TIMES HIGHER. STUDIES IN PATIENTS OF CHINESE ANCESTRY HAVE FOUND A STRONG ASSOCIATION BETWEEN THE RISK OF DEVELOPING SJS/TEN AND THE PRESENCE OF HLA-B*1502, AN INHERITED ALLELIC VARIANT OF THE HLA-B GENE. HLA-B*1502 IS FOUND ALMOST EXCLUSIVELY IN PATIENTS WITH ANCESTRY ACROSS BROAD AREAS OF ASIA. PATIENTS WITH ANCESTRY IN GENETICALLY AT-RISK POPULATIONS SHOULD BE SCREENED FOR THE PRESENCE OF HLA-B*1502 PRIOR TO INITIATING TREATMENT WITH TEGRETOL. PATIENTS TESTING POSITIVE FOR THE ALLELE SHOULD NOT BE TREATED WITH TEGRETOL UNLESS THE BENEFIT CLEARLY OUTWEIGHS THE RISK (SEE WARNINGS AND PRECAUTIONS, LABORATORY TESTS).
| molecular_weight = 236.269 g/mol
| bioavailability = 80%
<i><span style="color:#FF0000;">APLASTIC ANEMIA AND AGRANULOCYTOSIS: </span></i>
| protein_bound = 76%
| metabolism = [[Liver|Hepatic]]—by [[CYP3A4]], to active [[epoxide]] form (carbamazepine-10,11 epoxide)
* APLASTIC ANEMIA AND AGRANULOCYTOSIS HAVE BEEN REPORTED IN ASSOCIATION WITH THE USE OF TEGRETOL. DATA FROM A POPULATION-BASED CASE CONTROL STUDY DEMONSTRATE THAT THE RISK OF DEVELOPING THESE REACTIONS IS 5 TO 8 TIMES GREATER THAN IN THE GENERAL POPULATION. HOWEVER, THE OVERALL RISK OF THESE REACTIONS IN THE UNTREATED GENERAL POPULATION IS LOW, APPROXIMATELY SIX PATIENTS PER ONE MILLION POPULATION PER YEAR FOR AGRANULOCYTOSIS AND TWO PATIENTS PER ONE MILLION POPULATION PER YEAR FOR APLASTIC ANEMIA.
| elimination_half-life = 25–65 hours
| excretion = 2–3% excreted unchanged in urine
*ALTHOUGH REPORTS OF TRANSIENT OR PERSISTENT DECREASED PLATELET OR WHITE BLOOD CELL COUNTS ARE NOT UNCOMMON IN ASSOCIATION WITH THE USE OF TEGRETOL, DATA ARE NOT AVAILABLE TO ESTIMATE ACCURATELY THEIR INCIDENCE OR OUTCOME. HOWEVER, THE VAST MAJORITY OF THE CASES OF LEUKOPENIA HAVE NOT PROGRESSED TO THE MORE SERIOUS CONDITIONS OF APLASTIC ANEMIA OR AGRANULOCYTOSIS.
| pregnancy_US = C
| legal_AU =
*BECAUSE OF THE VERY LOW INCIDENCE OF AGRANULOCYTOSIS AND APLASTIC ANEMIA, THE VAST MAJORITY OF MINOR HEMATOLOGIC CHANGES OBSERVED IN MONITORING OF PATIENTS ON TEGRETOL ARE UNLIKELY TO SIGNAL THE OCCURRENCE OF EITHER ABNORMALITY. NONETHELESS, COMPLETE PRETREATMENT HEMATOLOGICAL TESTING SHOULD BE OBTAINED AS A BASELINE. IF A PATIENT IN THE COURSE OF TREATMENT EXHIBITS LOW OR DECREASED WHITE BLOOD CELL OR PLATELET COUNTS, THE PATIENT SHOULD BE MONITORED CLOSELY. *DISCONTINUATION OF THE DRUG SHOULD BE CONSIDERED IF ANY EVIDENCE OF SIGNIFICANT BONE MARROW DEPRESSION DEVELOPS.
| legal_UK = POM
|fdaLIADAdult======Epilepsy, Partial, generalized, and mixed types=====
| legal_US =
| legal_status =
Tegretol is indicated for use as an anticonvulsant drug. Evidence supporting efficacy of Tegretol as an anticonvulsant was derived from active drug-controlled studies that enrolled patients with the following seizure types:
| routes_of_administration = Oral
}}
*[[Partial seizures]] with complex symptomatology (psychomotor, temporal lobe). Patients with these seizures appear to show greater improvement than those with other types.
'''Carbamazepine ("CBZ")''' is an [[anticonvulsant]] and [[mood stabilizer|mood stabilizing]] drug, used primarily in the treatment of [[epilepsy]] and [[bipolar disorder]]. It is also used to treat [[Attention-deficit hyperactivity disorder|ADD]], [[ADHD]], [[schizophrenia]] and [[trigeminal neuralgia]].
*Mixed seizure patterns which include the above, or other partial or generalized seizures. Absence seizures (petit mal) do not appear to be controlled by Tegretol.
* Dosing Information
:*'''Monitoring:'''
:*Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in adults. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
:*'''Combination Therapy:'''
:*When the patient is receiving existing anticonvulsant therapy, add carbamazepine gradually while the existing anticonvulsant is maintained or gradually decreased; the exception is phenytoin, which may need to be increased.
:*Suspension:
:*1) The recommended initial adult dose of carbamazepine oral suspension for seizure control is 100 mg orally 4 times daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1200 mg/day; rarely, up to 1600 mg/day has been used.
:*2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
:*Tablets or Chewable Tablets:
:*1) The recommended initial adult dose of carbamazepine immediate-release tablets or chewable tablets for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1200 mg/day; rarely, up to 1600 mg/day has been given.
:*Extended-release Tablets or Capsules:*
:*1) The recommended initial adult dose of carbamazepine extended-release tablets or capsules for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 2 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1200 mg/day; rarely, up to 1600 mg/day has been given.
=====Trigeminal Neuralgia=====
*Tegretol is indicated in the treatment of the pain associated with true [[trigeminal neuralgia]].
*Beneficial results have also been reported in [[glossopharyngeal neuralgia]].
*This drug is not a simple analgesic and should not be used for the relief of trivial aches or pains.
* Dosing Information
:*a) The recommended initial dose for the treatment of [[trigeminal neuralgia]] is carbamazepine 200 mg/day given on day 1 as 50 mg ORALLY 4 times daily using oral suspension, as 100 mg orally twice daily using tablets (immediate-release, chewable tablets, or extended-release), or 200 mg once if using carbamazepine extended-release capsules. The dose may be increased by up to 200 mg/day using increments of 50 mg 4 times daily with oral suspension, increments of 100 mg every 12 hours for tablets (immediate-release, chewable tablets, or extended-release), or increments of 200 mg every 12 hours with extended-release capsules. Effective maintenance doses range from 200 to 1200 mg daily; for most patients the maintenance dose has been 400 to 800 mg/day. Do not exceed 1200 mg/day.
:*b) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
:*c) At least once every 3 months, attempts should be made to reduce the dose to the minimum effective dose or to discontinue the drug.
====Bipolar I disorder, Acute manic or mixed episodes====
* Dosing information
:* a) The recommended initial dose for the treatment of adults with acute manic or mixed episodes associated with bipolar I disorder is 200 mg orally twice daily. The dose may be adjusted in increments of 200 mg/day to achieve the optimum clinical response; doses above 1600 mg/day have not been evaluated
:*b) The longer-term or prophylactic use of Equetro(R) capsules for the treatment of bipolar mania has not been studied. Physicians who choose to prescribe this medication for extended periods of time should re-evaluate the long-term risks and benefits of the drug for the individual patient at regular intervals.
:*c) Most patients with bipolar disorder have responded to carbamazepine 600 to 1600 mg/day administered in divided doses, although some patients have required doses as high as 2000 to 3000 mg/day. Rapid-cycling patients usually require higher doses of 1000 to 2000 mg daily.
|fdaLIADPed======Epilepsy, Partial, generalized, and mixed types=====
* Dosing Information
*'''a) Combination Therapy:'''
:*1) When the patient is receiving existing anticonvulsant therapy, add carbamazepine gradually while the existing anticonvulsant is maintained or gradually decreased; the exception is phenytoin, which may need to be increased.
*'''b) Under 6 Years of Age'''
:*1) Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in children. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
:*Suspension:''
:*1) The recommended initial dose of carbamazepine oral suspension in children under 6 years of age for seizure control is 10 to 20 mg/kg/day orally in 4 divided doses. The dose may be increased at weekly intervals (maintenance usually below 35 mg/kg/day) to achieve clinical response or therapeutic plasma levels (4 to 12 mcg/mL). The safety of doses above 35 mg/kg is not established.
:*2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
:*3) Carbamazepine oral suspension was adequately absorbed from the gastrointestinal tract of newborns with a variety of seizure disorders. All infants were receiving other anticonvulsant agents in addition to carbamazepine. Maintenance therapy with carbamazepine doses of 5 to 8 mg/kg orally twice a day resulted in trough carbamazepine serum concentrations in the therapeutic range (10 to 40 mcmol/L). An elimination half-life ranging from 7.2 to 15.2 hours was observed; carbamazepine oral suspension may be useful for the treatment of neonatal seizures, and further study is required to evaluate its efficacy in this age group.
:*b) Tablets or Chewable Tablets:
:*1) The recommended initial dose of carbamazepine immediate-release tablets or chewable tablets in children under 6 years of age for seizure control is 10 to 20 mg/kg/day orally in 2 or 3 divided doses. The dose may be increased at weekly intervals (maintenance usually below 35 mg/kg/day) to achieve clinical response or therapeutic plasma levels (4 to 12 mcg/mL). The safety of doses above 35 mg/kg is not established.
:*2) In a review of dose-plasma concentration relationships in 196 children, usual pediatric dosage recommendations of 10 to 30 mg/kg/day were insufficient to achieve therapeutic serum concentrations in many patients, even those on monotherapy. Use of higher dosages requires careful evaluation of efficacy and potential toxicity.
*'''c) 6 to 12 Years of Age'''
:*1) Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in children. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
:*a) Suspension:
:*1) The recommended initial dose of carbamazepine oral suspension in children 6 to 12 years of age for seizure control is 50 mg orally 4 times daily. The dose may be increased by adding up to 100 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 400 to 800 mg/day). Generally, do not exceed 1000 mg/day.
:*2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
:*b) Tablets or Chewable Tablets:
:*1) The recommended initial dose of carbamazepine immediate-release tablets or chewable tablets in children 6 to 12 years of age for seizure control is 100 mg orally twice daily. The dose may be increased by adding up to 100 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 400 to 800 mg/day). Generally, do not exceed 1000 mg/day.
:*c) Extended-release Capsules:
:*1) In patients under 12 years of age, extended-release capsules may be used if the patient is currently receiving immediate-release product at 400 mg/day or greater. The same dose of the extended-release capsule may be given in 2 divided doses.
:*d) Extended-release Tablets:
:*1) The recommended initial dose of carbamazepine extended-release tablets in children 6 to 12 years of age for seizure control is 100 mg orally twice daily. The dose may be increased by adding up to 100 mg/day in 2 divided doses at weekly intervals to the minimum effective level (usually 400 to 800 mg/day). Generally, do not exceed 1000 mg/day.
:*2) In a review of dose-plasma concentration relationships in 196 children, usual pediatric dosage recommendations of 10 to 30 mg/kg/day were insufficient to achieve therapeutic serum concentrations in many patients, even those on monotherapy. Use of higher dosages requires careful evaluation of efficacy and potential toxicity.
*'''d) Over 12 years of Age'''
:*1) Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in children. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
:*a) Suspension:
:*1) The recommended initial dose of carbamazepine oral suspension in adolescents over 12 years of age for seizure control is 100 mg orally 4 times daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1000 mg/day in adolescents 12 to 15 years of age or 1200 mg/day in adolescents older than 15 years.
:*2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
:*b) Tablets or Chewable Tablets:
:*1) The recommended initial dose of carbamazepine immediate-release tablets or chewable tablets in adolescents over 12 years of age for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1000 mg/day in adolescents 12 to 15 years of age or 1200 mg/day in adolescents older than 15 years.
:*c) Extended-release Tablets or Capsules:
:*1) The recommended initial dose of carbamazepine extended-release tablets or capsules in adolescents over 12 years of age for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 2 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1000 mg/day in adolescents 12 to 15 years of age or 1200 mg/day in adolescents older than 15 years.
:*2) In a review of dose-plasma concentration relationships in 196 children, usual pediatric dosage recommendations of 10 to 30 mg/kg/day were insufficient to achieve therapeutic serum concentrations in many patients, even those on monotherapy. Use of higher dosages requires careful evaluation of efficacy and potential toxicity.
*The safety and effectiveness of Equitro(R) are not established in pediatric and adolescent patients.
*Withdrawal Of Therapy
:* When carbamazepine therapy is to be discontinued, gradually taper to minimize the possibility of increased seizure frequency.
:*Withdrawal of anticonvulsant medication in children free of seizures for 2 to 4 years appears to be safe, with the majority of children remaining free of seizures after medication withdrawal. In a prospective study, anticonvulsant medications were discontinued in 88 epileptic children who had not had a seizure for 2 to 4 years. :*Anticonvulsants were withdrawn gradually over 2 to 3 months. The mean age at the time of the first seizure was 5 years (range, 0 to 16 years), with the mean age at the time of the last seizure being 8.7 years (range, to 22 years). The mean duration of seizures was 3.7 years (range, 0 to 17.4 years). Sixty-six (75%) patients remained free of seizures after withdrawal of anticonvulsants, and the overall probability of remaining seizure-free was 79% at 12 months, 77% at 24 months, and 74% at 30 months. The risk of recurrence of seizures was highest within the first few months of initiation of withdrawal. Of 22 patients with recurrence of seizures, 9 occurred within the first 3 months, 13 in the first 6 months, and 18 (82%) within the first year of withdrawal. The type of seizure, age at onset, and EEG characteristics were considered important in predicting the outcome of anticonvulsant withdrawal. It is recommended that anticonvulsants be discontinued in children with good prognostic factors after a 2-year period without seizures.
|offLabelPedGuideSupport=*There is limited information regarding <i>Off-Label Guideline-Supported Use</i> of Carbamazepine in pediatric patients.
|offLabelPedNoGuideSupport=*There is limited information regarding <i>Off-Label Non–Guideline-Supported Use</i> of Carbamazepine in pediatric patients.
|contraindications=*Tegretol should not be used in patients with a history of previous bone marrow depression, hypersensitivity to the drug, or known sensitivity to any of the tricyclic compounds, such as amitriptyline, desipramine, imipramine, protriptyline, nortriptyline, etc. Likewise, on theoretical grounds its use with monoamine oxidase (MAO) inhibitors is not recommended. Before administration of Tegretol, MAO inhibitors should be discontinued for a minimum of 14 days, or longer if the clinical situation permits.
*Coadministration of carbamazepine and [[nefazodone]] may result in insufficient plasma concentrations of nefazodone and its active metabolite to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated.
|warnings='''Serious Dermatologic Reactions'''
*Serious and sometimes fatal dermatologic reactions, including [[toxic epidermal necrolysis]] (TEN) and [[Stevens-Johnson syndrome]] (SJS), have been reported with Tegretol treatment. The risk of these events is estimated to be about 1 to 6 per 10,000 new users in countries with mainly Caucasian populations. However, the risk in some Asian countries is estimated to be about 10 times higher. Tegretol should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed and alternative therapy should be considered.
'''SJS/TEN and HLA-B*1502 Allele'''
*Retrospective case-control studies have found that in patients of Chinese ancestry there is a strong association between the risk of developing SJS/TEN with carbamazepine treatment and the presence of an inherited variant of the [[HLA-B]] gene, HLA-B*1502. The occurrence of higher rates of these reactions in countries with higher frequencies of this allele suggests that the risk may be increased in allele-positive individuals of any ethnicity.
*Across Asian populations, notable variation exists in the prevalence of HLA-B*1502. Greater than 15% of the population is reported positive in Hong Kong, Thailand, Malaysia, and parts of the Philippines, compared to about 10% in Taiwan and 4% in North China. South Asians, including Indians, appear to have intermediate prevalence of HLA-B*1502, averaging 2% to 4%, but higher in some groups. HLA-B*1502 is present in less than 1% of the population in Japan and Korea.
*HLA-B*1502 is largely absent in individuals not of Asian origin (e.g., Caucasians, African-Americans, Hispanics, and Native Americans).
*Prior to initiating Tegretol therapy, testing for HLA-B*1502 should be performed in patients with ancestry in populations in which HLA-B*1502 may be present. In deciding which patients to screen, the rates provided above for the prevalence of HLA-B*1502 may offer a rough guide, keeping in mind the limitations of these figures due to wide variability in rates even within ethnic groups, the difficulty in ascertaining ethnic ancestry, and the likelihood of mixed ancestry. Tegretol should not be used in patients positive for HLA-B*1502 unless the benefits clearly outweigh the risks. Tested patients who are found to be negative for the allele are thought to have a low risk of SJS/TEN (see BOXED WARNING and PRECAUTIONS, Laboratory Tests).
*Over 90% of Tegretol treated patients who will experience SJS/TEN have this reaction within the first few months of treatment. This information may be taken into consideration in determining the need for screening of genetically at-risk patients currently on Tegretol.
*The HLA-B*1502 allele has not been found to predict risk of less severe adverse cutaneous reactions from Tegretol such as maculopapular eruption (MPE) or to predict [[Drug Reaction with Eosinophilia and Systemic Symptoms]] (DRESS).
*Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Chinese ancestry taking other antiepileptic drugs associated with SJS/TEN, including [[phenytoin]]. Consideration should be given to avoiding use of other drugs associated with SJS/TEN in HLA-B*1502 positive patients, when alternative therapies are otherwise equally acceptable.
'''Hypersensitivity Reactions and HLA-A*3101 Allele'''
*Retrospective case-control studies in patients of European, Korean, and Japanese ancestry have found a moderate association between the risk of developing hypersensitivity reactions and the presence of HLA-A*3101, an inherited allelic variant of the HLA-A gene, in patients using carbamazepine. These hypersensitivity reactions include SJS/TEN, maculopapular eruptions, and Drug Reaction with [[Eosinophilia]] and Systemic Symptoms (see DRESS/Multiorgan hypersensitivity below).
*HLA-A*3101 is expected to be carried by more than 15% of patients of Japanese, Native American, Southern Indian (for example, Tamil Nadu) and some Arabic ancestry; up to about 10% in patients of Han Chinese, Korean, European, Latin American, and other Indian ancestry; and up to about 5% in African-Americans and patients of Thai, Taiwanese, and Chinese (Hong Kong) ancestry.
*The risks and benefits of Tegretol therapy should be weighed before considering Tegretol in patients known to be positive for HLA-A*3101.
*Application of HLA genotyping as a screening tool has important limitations and must never substitute for appropriate clinical vigilance and patient management. Many HLA-B*1502-positive and HLA-A*3101-positive patients treated with Tegretol will not develop SJS/TEN or other hypersensitivity reactions, and these reactions can still occur infrequently in HLA-B*1502-negative and HLA-A*3101-negative patients of any ethnicity. The role of other possible factors in the development of, and morbidity from, SJS/TEN and other hypersensitivity reactions, such as [[antiepileptic]] drug (AED) dose, compliance, concomitant medications, comorbidities, and the level of dermatologic monitoring, have not been studied.
'''Aplastic Anemia and Agranulocytosis'''
*[[Aplastic anemia]] and [[agranulocytosis]] have been reported in association with the use of TEGRETOL (see BOXED WARNING). Patients with a history of adverse hematologic reaction to any drug may be particularly at risk of bone marrow depression.
'''Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity'''
*Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multiorgan hypersensitivity, has occurred with Tegretol. Some of these events have been fatal or life-threatening. DRESS typically, although not exclusively, presents with [[fever]], [[rash]], and/or [[lymphadenopathy]], in association with other organ system involvement, such as [[hepatitis]], [[nephritis]], hematologic abnormalities, [[myocarditis]], or [[myositis]] sometimes resembling an acute viral infection. [[Eosinophilia]] is often present. This disorder is variable in its expression, and other organ systems not noted here may be involved. It is important to note that early manifestations of [[hypersensitivity]] (e.g., [[fever]], [[lymphadenopathy]]) may be present even though rash is not evident. If such signs or symptoms are present, the patient should be evaluated immediately. Tegretol should be discontinued if an alternative etiology for the signs or symptoms cannot be established.
'''Hypersensitivity'''
*Hypersensitivity reactions to carbamazepine have been reported in patients who previously experienced this reaction to anticonvulsants including phenytoin, primidone, and phenobarbital. If such history is present, benefits and risks should be carefully considered and, if carbamazepine is initiated, the signs and symptoms of [[hypersensitivity]] should be carefully monitored.
*In patients who have exhibited hypersensitivity reactions to carbamazepine, approximately 25 to 30% may experience hypersensitivity reactions with [[oxcarbazepine]] (Trileptal®).
'''Suicidal Behavior and Ideation'''
*Antiepileptic drugs (AEDs), including Tegretol, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
*Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.
*The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
*The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5 to 100 years) in the clinical trials analyzed. Table 1 shows absolute and relative risk by indication for all evaluated AEDs.
*The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
*Anyone considering prescribing Tegretol or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
*Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
'''General'''
*Tegretol has shown mild [[anticholinergic]] activity; therefore, patients with increased intraocular pressure should be closely observed during therapy.
*Because of the relationship of the drug to other tricyclic compounds, the possibility of activation of a latent psychosis and, in elderly patients, of confusion or agitation should be borne in mind.
*The use of Tegretol should be avoided in patients with a history of [[hepatic porphyria]] (e.g., [[acute intermittent porphyria]], [[variegate porphyria]], [[porphyria cutanea tarda]]). Acute attacks have been reported in such patients receiving Tegretol therapy. Carbamazepine administration has also been demonstrated to increase porphyrin precursors in rodents, a presumed mechanism for the induction of acute attacks of porphyria.
*As with all antiepileptic drugs, Tegretol should be withdrawn gradually to minimize the potential of increased seizure frequency.
'''Usage in Pregnancy'''
*Carbamazepine can cause fetal harm when administered to a pregnant woman.
*Epidemiological data suggest that there may be an association between the use of carbamazepine during pregnancy and congenital malformations, including spina bifida. There have also been reports that associate carbamazepine with developmental disorders and congenital anomalies (e.g., craniofacial defects, cardiovascular malformations, hypospadias, and anomalies involving various body systems). Developmental delays based on neurobehavioral assessments have been reported. When treating or counseling women of childbearing potential, the prescribing physician will wish to weigh the benefits of therapy against the risks. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
*Retrospective case reviews suggest that, compared with monotherapy, there may be a higher prevalence of teratogenic effects associated with the use of anticonvulsants in combination therapy. Therefore, if therapy is to be continued, monotherapy may be preferable for pregnant women.
*In humans, transplacental passage of carbamazepine is rapid (30 to 60 minutes), and the drug is accumulated in the fetal tissues, with higher levels found in liver and kidney than in brain and lung.
*Carbamazepine has been shown to have adverse effects in reproduction studies in rats when given orally in dosages 10 to 25 times the maximum human daily dosage (MHDD) of 1200 mg on a mg/kg basis or 1.5 to 4 times the MHDD on a mg/m2 basis. In rat teratology studies, 2 of 135 offspring showed kinked ribs at 250 mg/kg and 4 of 119 offspring at 650 mg/kg showed other anomalies (cleft palate, 1; talipes, 1; anophthalmos, 2). In reproduction studies in rats, nursing offspring demonstrated a lack of weight gain and an unkempt appearance at a maternal dosage level of 200 mg/kg.
*Antiepileptic drugs should not be discontinued abruptly in patients in whom the drug is administered to prevent major seizures because of the strong possibility of precipitating status epilepticus with attendant hypoxia and threat to life. In individual cases where the severity and frequency of the seizure disorder are such that removal of medication does not pose a serious threat to the patient, discontinuation of the drug may be considered prior to and during pregnancy, although it cannot be said with any confidence that even minor seizures do not pose some hazard to the developing embryo or fetus.
*Tests to detect defects using currently accepted procedures should be considered a part of routine prenatal care in childbearing women receiving carbamazepine.
*There have been a few cases of neonatal seizures and/or respiratory depression associated with maternal Tegretol and other concomitant anticonvulsant drug use. A few cases of neonatal vomiting, diarrhea, and/or decreased feeding have also been reported in association with maternal Tegretol use. These symptoms may represent a neonatal withdrawal syndrome.
*To provide information regarding the effects of in utero exposure to Tegretol, physicians are advised to recommend that pregnant patients taking Tegretol enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.
====PRECAUTIONS====
'''General'''
*Before initiating therapy, a detailed history and physical examination should be made.
*Tegretol should be used with caution in patients with a mixed seizure disorder that includes [[atypical absence seizures]], since in these patients Tegretol has been associated with increased frequency of generalized convulsions.
*Therapy should be prescribed only after critical benefit-to-risk appraisal in patients with a history of cardiac conduction disturbance, including second- and [[third-degree AV heart block]]; cardiac, hepatic, or renal damage; adverse hematologic or hypersensitivity reaction to other drugs, including reactions to other [[anticonvulsants]]; or interrupted courses of therapy with Tegretol.
*AV heart block, including second- and third-degree block, have been reported following Tegretol treatment. This occurred generally, but not solely, in patients with underlying EKG abnormalities or risk factors for conduction disturbances.
*Hepatic effects, ranging from slight elevations in liver enzymes to rare cases of hepatic failure have been reported (see ADVERSE REACTIONS and PRECAUTIONS, Laboratory Tests). In some cases, hepatic effects may progress despite discontinuation of the drug. In addition rare instances of vanishing bile duct syndrome have been reported. This syndrome consists of a cholestatic process with a variable clinical course ranging from fulminant to indolent, involving the destruction and disappearance of the intrahepatic bile ducts. Some, but not all, cases are associated with features that overlap with other immunoallergenic syndromes such as multiorgan hypersensitivity ([[DRESS syndrome]]) and serious dermatologic reactions. As an example there has been a report of vanishing bile duct syndrome associated with Stevens-Johnson syndrome and in another case an association with fever and eosinophilia.
*Since a given dose of Tegretol suspension will produce higher peak levels than the same dose given as the tablet, it is recommended that patients given the suspension be started on lower doses and increased slowly to avoid unwanted side effects.
*Tegretol suspension contains sorbitol and, therefore, should not be administered to patients with rare hereditary problems of fructose intolerance.
'''Laboratory Tests'''
*For genetically at-risk patients (see WARNINGS), high-resolution ‘HLA-B*1502 typing’ is recommended. The test is positive if either one or two HLA-B*1502 alleles are detected and negative if no HLA-B*1502 alleles are detected.
*Complete pretreatment blood counts, including platelets and possibly [[reticulocytes]] and serum iron, should be obtained as a baseline. If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely. Discontinuation of the drug should be considered if any evidence of significant bone marrow depression develops.
*Baseline and periodic evaluations of liver function, particularly in patients with a history of liver disease, must be performed during treatment with this drug since liver damage may occur. Carbamazepine should be discontinued, based on clinical judgment, if indicated by newly occurring or worsening clinical or laboratory evidence of liver dysfunction or hepatic damage, or in the case of active liver disease.
*Baseline and periodic eye examinations, including [[slit-lamp]], [[funduscopy]], and [[tonometry]], are recommended since many [[phenothiazines]] and related drugs have been shown to cause eye changes.
*Baseline and periodic complete [[urinalysis]] and [[BUN]] determinations are recommended for patients treated with this agent because of observed renal dysfunction.
*Monitoring of blood levels has increased the efficacy and safety of anticonvulsants. This monitoring may be particularly useful in cases of dramatic increase in seizure frequency and for verification of compliance. In addition, measurement of drug serum levels may aid in determining the cause of toxicity when more than one medication is being used.
*Thyroid function tests have been reported to show decreased values with Tegretol administered alone.
*[[Hyponatremia]] has been reported in association with Tegretol use, either alone or in combination with other drugs.
*Interference with some pregnancy tests has been reported.
'''Drug Interactions'''
*There has been a report of a patient who passed an orange rubbery precipitate in his stool the day after ingesting Tegretol suspension immediately followed by Thorazine®* solution. Subsequent testing has shown that mixing Tegretol suspension and chlorpromazine solution (both generic and brand name) as well as Tegretol suspension and liquid Mellaril®, resulted in the occurrence of this precipitate. Because the extent to which this occurs with other liquid medications is not known, Tegretol suspension should not be administered simultaneously with other liquid medicinal agents or diluents.
*Clinically meaningful drug interactions have occurred with concomitant medications and include (but are not limited to) the following:
'''Agents That May Affect Tegretol Plasma Levels'''
*When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required.
'''Agents That Increase Carbamazepine Levels'''
*CYP3A4 inhibitors inhibit Tegretol metabolism and can thus increase plasma carbamazepine levels. Drugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides, erythromycin, troleandomycin, clarithromycin, fluoxetine, fluvoxamine, trazodone, olanzapine, loratadine, terfenadine, omeprazole, oxybutynin, dantrolene, isoniazid, niacinamide, nicotinamide, ibuprofen, propoxyphene, azoles (e.g., ketaconazole, itraconazole, fluconazole, voriconazole), acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors.
*Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide. Coadministration of inhibitors of human microsomal epoxide hydrolase may result in increased carbamazepine-10,11 epoxide plasma concentrations. Accordingly, the dosage of Tegretol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, or valproic acid.
'''Agents That Decrease Carbamazepine Levels'''
*[[CYP3A4]] inducers can increase the rate of Tegretol metabolism. Drugs that have been shown, or that would be expected, to decrease plasma carbamazepine levels include [[cisplatin]], [[doxorubicin]] HCl, [[felbamate]], [[fosphenytoin]], [[rifampin]], [[phenobarbital]], [[phenytoin]], [[primidone]], [[methsuximide]], [[theophylline]], [[aminophylline]].
'''Effect of Tegretol on Plasma Levels of Concomitant Agents'''
'''Decreased Levels of Concomitant Medications'''
*Tegretol is a potent inducer of hepatic 3A4 and is also known to be an inducer of [[CYP1A2]], [[2B6]], [[2C9]]/19 and may therefore reduce plasma concentrations of co-medications mainly metabolized by CYP 1A2, 2B6, 2C9/19 and 3A4, through induction of their metabolism. When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
:*When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced.
:*When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
:*The use of concomitant strong [[CYP3A4]] inducers such as carbamazepine should be avoided with temsirolimus. If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered.
:*The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced.
:*Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS).
:*Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
*In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
'''Other Drug Interactions'''
*Cyclophosphamide is an inactive prodrug and is converted to its active metabolite in part by CYP3A. The rate of metabolism and the leukopenic activity of cyclophosphamide are reportedly increased by chronic coadministration of CYP3A4 inducers. There is a potential for increased cyclophosphamide toxicity when coadministered with carbamazepine.
*Concomitant administration of carbamazepine and lithium may increase the risk of neurotoxic side effects.
*Concomitant use of carbamazepine and isoniazid has been reported to increase isoniazid-induced [[hepatotoxicity]].
*Concomitant medication with Tegretol and some diuretics (e.g., hydrochlorothiazide, furosemide) may lead to symptomatic [[hyponatremia]].
*Alterations of thyroid function have been reported in combination therapy with other anticonvulsant medications.
*Concomitant use of Tegretol with [[hormonal contraceptive]] products (e.g., oral, and levonorgestrel subdermal implant contraceptives) may render the contraceptives less effective because the plasma concentrations of the hormones may be decreased. Breakthrough bleeding and unintended pregnancies have been reported. Alternative or back-up methods of contraception should be considered.
*Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other non-depolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
|clinicalTrials=*If adverse reactions are of such severity that the drug must be discontinued, the physician must be aware that abrupt discontinuation of any anticonvulsant drug in a responsive epileptic patient may lead to seizures or even status epilepticus with its life-threatening hazards.
*The most severe adverse reactions have been observed in the hemopoietic system and skin (see BOXED WARNING), the liver, and the cardiovascular system.
*The most frequently observed adverse reactions, particularly during the initial phases of therapy, are dizziness, drowsiness, unsteadiness, nausea, and vomiting. To minimize the possibility of such reactions, therapy should be initiated at the lowest dosage recommended.
*The following additional adverse reactions have been reported:
*Skin: [[Toxic epidermal necrolysis]] (TEN) and [[Stevens-Johnson syndrome]] (SJS) (see BOXED WARNING), Acute Generalized Exanthematous Pustulosis (AGEP), pruritic and erythematous rashes, [[urticaria]], [[photosensitivity]] reactions, alterations in skin pigmentation, [[exfoliative dermatitis]], [[erythema multiforme]] and nodosum, [[purpura]], aggravation of disseminated lupus erythematosus, alopecia, diaphoresis, onychomadesis and hirsutism. In certain cases, discontinuation of therapy may be necessary.
*Cardiovascular System: Congestive heart failure, edema, aggravation of [[hypertension]], [[hypotension]], [[syncope]] and collapse, aggravation of [[coronary artery disease]], [[arrhythmias]] and [[AV block]], [[thrombophlebitis]], [[thromboembolism]] (e.g., pulmonary embolism), and adenopathy or lymphadenopathy.
*Some of these cardiovascular complications have resulted in fatalities. Myocardial infarction has been associated with other tricyclic compounds.
*Liver: Abnormalities in liver function tests, cholestatic and [[hepatocellular jaundice]], [[hepatitis]], very rare cases of hepatic failure.
*Pancreatic: [[Pancreatitis]].
*Respiratory System: Pulmonary hypersensitivity characterized by [[fever]], [[dyspnea]], [[pneumonitis]], or [[pneumonia]].
*Genitourinary System: Urinary frequency, acute urinary retention, oliguria with elevated blood pressure, [[azotemia]], [[renal failure]], and [[impotence]]. [[Albuminuria]], [[glycosuria]], elevated [[BUN]], and microscopic deposits in the urine have also been reported. There have been very rare reports of impaired male fertility and/or abnormal spermatogenesis.
*Testicular atrophy occurred in rats receiving Tegretol orally from 4 to 52 weeks at dosage levels of 50 to 400 mg/kg/day. Additionally, rats receiving Tegretol in the diet for 2 years at dosage levels of 25, 75, and 250 mg/kg/day had a dose-related incidence of testicular atrophy and aspermatogenesis. In dogs, it produced a brownish discoloration, presumably a metabolite, in the urinary bladder at dosage levels of 50 mg/kg and higher. Relevance of these findings to humans is unknown.
*There have been reports of associated paralysis and other symptoms of cerebral arterial insufficiency, but the exact relationship of these reactions to the drug has not been established.
*Isolated cases of [[neuroleptic malignant syndrome]] have been reported both with and without concomitant use of psychotropic drugs.
*Digestive System: Nausea, vomiting, gastric distress and abdominal pain, diarrhea, constipation, anorexia, and dryness of the mouth and pharynx, including glossitis and stomatitis.
*Eyes: Scattered punctate cortical lens opacities, increased intraocular pressure as well as conjunctivitis, have been reported. Although a direct causal relationship has not been established, many phenothiazines and related drugs have been shown to cause eye changes.
*Musculoskeletal System: Aching joints and muscles, and leg cramps.
*Metabolism: Fever and chills. Inappropriate antidiuretic hormone (ADH) secretion syndrome has been reported. Cases of frank water intoxication, with decreased serum sodium ([[hyponatremia]]) and confusion, have been reported in association with Tegretol use. Decreased levels of plasma calcium leading to osteoporosis have been reported.
*Isolated cases of a lupus erythematosus-like syndrome have been reported. There have been occasional reports of elevated levels of cholesterol, HDL cholesterol, and triglycerides in patients taking anticonvulsants.
*A case of [[aseptic meningitis]], accompanied by myoclonus and peripheral [[eosinophilia]], has been reported in a patient taking carbamazepine in combination with other medications. The patient was successfully dechallenged, and the meningitis reappeared upon rechallenge with carbamazepine.
'''DRUG ABUSE AND DEPENDENCE'''
*No evidence of abuse potential has been associated with Tegretol, nor is there evidence of psychological or physical dependence in humans.
|postmarketing=*There is limited information regarding <i>Postmarketing Experience</i> of {{PAGENAME}} in the drug label.
<!--Drug Interactions-->
|drugInteractions=*There has been a report of a patient who passed an orange rubbery precipitate in his stool the day after ingesting Tegretol suspension immediately followed by Thorazine®* solution. Subsequent testing has shown that mixing Tegretol suspension and chlorpromazine solution (both generic and brand name) as well as Tegretol suspension and liquid Mellaril®, resulted in the occurrence of this precipitate. Because the extent to which this occurs with other liquid medications is not known, Tegretol suspension should not be administered simultaneously with other liquid medicinal agents or diluents.
*Clinically meaningful drug interactions have occurred with concomitant medications and include (but are not limited to) the following:
'''Agents That May Affect Tegretol Plasma Levels'''
*When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required.
'''Agents That Increase Carbamazepine Levels'''
*CYP3A4 inhibitors inhibit Tegretol metabolism and can thus increase plasma carbamazepine levels. Drugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides, erythromycin, troleandomycin, clarithromycin, fluoxetine, fluvoxamine, trazodone, olanzapine, loratadine, terfenadine, omeprazole, oxybutynin, dantrolene, isoniazid, niacinamide, nicotinamide, ibuprofen, propoxyphene, azoles (e.g., [[ketaconazole]], [[itraconazole]], [[fluconazole]], [[voriconazole]]), [[acetazolamide]], [[verapamil]], [[ticlopidine]], grapefruit juice, and protease inhibitors.
*Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide. Coadministration of inhibitors of human microsomal epoxide hydrolase may result in increased carbamazepine-10,11 epoxide plasma concentrations. Accordingly, the dosage of Tegretol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, or valproic acid.
'''Agents That Decrease Carbamazepine Levels'''
*[[CYP3A4]] inducers can increase the rate of Tegretol metabolism. Drugs that have been shown, or that would be expected, to decrease plasma carbamazepine levels include [[cisplatin]], [[doxorubicin]] HCl, [[felbamate]], [[fosphenytoin]], [[rifampin]], [[phenobarbital]], [[phenytoin]], [[primidone]], [[methsuximide]], [[theophylline]], [[aminophylline]].
'''Effect of Tegretol on Plasma Levels of Concomitant Agents'''
'''Decreased Levels of Concomitant Medications'''
*Tegretol is a potent inducer of hepatic 3A4 and is also known to be an inducer of CYP1A2, 2B6, 2C9/19 and may therefore reduce plasma concentrations of co-medications mainly metabolized by CYP 1A2, 2B6, 2C9/19 and 3A4, through induction of their metabolism. When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
:*When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced.
:*When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
:*The use of concomitant strong CYP3A4 inducers such as carbamazepine should be avoided with temsirolimus. If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered.
:*The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced.
:*Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS).
:*Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
*In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
'''Other Drug Interactions'''
*Cyclophosphamide is an inactive prodrug and is converted to its active metabolite in part by CYP3A. The rate of metabolism and the leukopenic activity of cyclophosphamide are reportedly increased by chronic coadministration of CYP3A4 inducers. There is a potential for increased cyclophosphamide toxicity when coadministered with carbamazepine.
*Concomitant administration of carbamazepine and lithium may increase the risk of neurotoxic side effects.
*Concomitant use of carbamazepine and isoniazid has been reported to increase isoniazid-induced hepatotoxicity.
*Concomitant medication with Tegretol and some diuretics (e.g., hydrochlorothiazide, furosemide) may lead to symptomatic hyponatremia.
*Alterations of thyroid function have been reported in combination therapy with other anticonvulsant medications.
*Concomitant use of Tegretol with hormonal contraceptive products (e.g., oral, and levonorgestrel subdermal implant contraceptives) may render the contraceptives less effective because the plasma concentrations of the hormones may be decreased. Breakthrough bleeding and unintended pregnancies have been reported. Alternative or back-up methods of contraception should be considered.
*Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other non-depolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
|FDAPregCat=D
|useInPregnancyFDA=* '''Pregnancy Category D'''
*Carbamazepine can cause fetal harm when administered to a pregnant woman.
*Epidemiological data suggest that there may be an association between the use of carbamazepine during pregnancy and congenital malformations, including spina bifida. There have also been reports that associate carbamazepine with developmental disorders and congenital anomalies (e.g., craniofacial defects, cardiovascular malformations, hypospadias, and anomalies involving various body systems). Developmental delays based on neurobehavioral assessments have been reported. When treating or counseling women of childbearing potential, the prescribing physician will wish to weigh the benefits of therapy against the risks. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
*Retrospective case reviews suggest that, compared with monotherapy, there may be a higher prevalence of teratogenic effects associated with the use of anticonvulsants in combination therapy. Therefore, if therapy is to be continued, monotherapy may be preferable for pregnant women.
*In humans, transplacental passage of carbamazepine is rapid (30 to 60 minutes), and the drug is accumulated in the fetal tissues, with higher levels found in liver and kidney than in brain and lung.
|useInPregnancyAUS=* '''Australian Drug Evaluation Committee (ADEC) Pregnancy Category'''
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of {{PAGENAME}} in women who are pregnant.
|useInLaborDelivery=*The effect of Tegretol on human labor and delivery is unknown.
|useInNursing=*Tegretol and its epoxide metabolite are transferred to breast milk. The ratio of the concentration in breast milk to that in maternal plasma is about 0.4 for Tegretol and about 0.5 for the epoxide. The estimated doses given to the newborn during breastfeeding are in the range of 2 to 5 mg daily for Tegretol and 1 to 2 mg daily for the epoxide.
*Because of the potential for serious adverse reactions in nursing infants from carbamazepine, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
|useInPed=*Substantial evidence of Tegretol’s effectiveness for use in the management of children with epilepsy is derived from clinical investigations performed in adults and from studies in several in vitro systems which support the conclusion that (1) the pathogenetic mechanisms underlying seizure propagation are essentially identical in adults and children, and (2) the mechanism of action of carbamazepine in treating seizures is essentially identical in adults and children.
*Taken as a whole, this information supports a conclusion that the generally accepted therapeutic range of total carbamazepine in plasma (i.e. 4 to 12 mcg/mL) is the same in children and adults.
*The evidence assembled was primarily obtained from short-term use of carbamazepine. The safety of carbamazepine in children has been systematically studied up to 6 months. No longer-term data from clinical trials is available.
|useInGeri=*No systematic studies in geriatric patients have been conducted.
|useInGender=*There is no FDA guidance on the use of {{PAGENAME}} with respect to specific gender populations.
|useInRace=*There is no FDA guidance on the use of {{PAGENAME}} with respect to specific racial populations.
|useInRenalImpair=*There is no FDA guidance on the use of {{PAGENAME}} in patients with renal impairment.
|useInHepaticImpair=*There is no FDA guidance on the use of {{PAGENAME}} in patients with hepatic impairment.
|useInReproPotential=*There is no FDA guidance on the use of {{PAGENAME}} in women of reproductive potentials and males.
|useInImmunocomp=*There is no FDA guidance one the use of {{PAGENAME}} in patients who are immunocompromised.
|administration=*Tegretol suspension in combination with liquid chlorpromazine or thioridazine results in precipitate formation, and, in the case of chlorpromazine, there has been a report of a patient passing an orange rubbery precipitate in the stool following coadministration of the two drugs (see PRECAUTIONS, Drug Interactions). Because the extent to which this occurs with other liquid medications is not known, Tegretol suspension should not be administered simultaneously with other liquid medications or diluents.
*Monitoring of blood levels has increased the efficacy and safety of anticonvulsants (see PRECAUTIONS, Laboratory Tests). Dosage should be adjusted to the needs of the individual patient. A low initial daily dosage with a gradual increase is advised. As soon as adequate control is achieved, the dosage may be reduced very gradually to the minimum effective level. Medication should be taken with meals.
*Since a given dose of Tegretol suspension will produce higher peak levels than the same dose given as the tablet, it is recommended to start with low doses (children 6 to 12 years: ½ teaspoon q.i.d.) and to increase slowly to avoid unwanted side effects.
*Conversion of patients from oral Tegretol tablets to Tegretol suspension: Patients should be converted by administering the same number of mg per day in smaller, more frequent doses (i.e., b.i.d. tablets to t.i.d. suspension).
*Tegretol-XR is an extended-release formulation for twice-a-day administration. When converting patients from Tegretol conventional tablets to Tegretol-XR, the same total daily mg dose of Tegretol-XR should be administered. Tegretol-XR tablets must be swallowed whole and never crushed or chewed. Tegretol-XR tablets should be inspected for chips or cracks. Damaged tablets, or tablets without a release portal, should not be consumed. Tegretol-XR tablet coating is not absorbed and is excreted in the feces; these coatings may be noticeable in the stool.
'''Epilepsy'''
*Adults and children over 12 years of age-Initial: Either 200 mg b.i.d. for tablets and XR tablets, or 1 teaspoon q.i.d. for suspension (400 mg/day). Increase at weekly intervals by adding up to 200 mg/day using a b.i.d. regimen of Tegretol-XR or a t.i.d. or q.i.d. regimen of the other formulations until the optimal response is obtained. Dosage generally should not exceed 1000 mg daily in children 12 to 15 years of age, and 1200 mg daily in patients above 15 years of age. Doses up to 1600 mg daily have been used in adults in rare instances. Maintenance: Adjust dosage to the minimum effective level, usually 800 to 1200 mg daily.
*Children 6 to 12 years of age-Initial: Either 100 mg b.i.d. for tablets or XR tablets, or ½ teaspoon q.i.d. for suspension (200 mg/day). Increase at weekly intervals by adding up to 100 mg/day using a b.i.d. regimen of Tegretol-XR or a t.i.d. or q.i.d. regimen of the other formulations until the optimal response is obtained. Dosage generally should not exceed 1000 mg daily. Maintenance: Adjust dosage to the minimum effective level, usually 400 to 800 mg daily.
*Children under 6 years of age-Initial: 10 to 20 mg/kg/day b.i.d. or t.i.d. as tablets, or q.i.d. as suspension. Increase weekly to achieve optimal clinical response administered t.i.d. or q.i.d. Maintenance: Ordinarily, optimal clinical response is achieved at daily doses below 35 mg/kg. If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the therapeutic range. No recommendation regarding the safety of carbamazepine for use at doses above 35 mg/kg/24 hours can be made.
*Combination Therapy: Tegretol may be used alone or with other anticonvulsants. When added to existing anticonvulsant therapy, the drug should be added gradually while the other anticonvulsants are maintained or gradually decreased, except phenytoin, which may have to be increased (see PRECAUTIONS, Drug Interactions, and Pregnancy Category D).
'''Trigeminal Neuralgia'''
*Initial: On the first day, either 100 mg b.i.d. for tablets or XR tablets, or ½ teaspoon q.i.d. for suspension, for a total daily dose of 200 mg. This daily dose may be increased by up to 200 mg/day using increments of 100 mg every 12 hours for tablets or XR tablets, or 50 mg (½ teaspoon) q.i.d. for suspension, only as needed to achieve freedom from pain. Do not exceed 1200 mg daily. Maintenance: Control of pain can be maintained in most patients with 400 to 800 mg daily. However, some patients may be maintained on as little as 200 mg daily, while others may require as much as 1200 mg daily. At least once every 3 months throughout the treatment period, attempts should be made to reduce the dose to the minimum effective level or even to discontinue the drug.
|monitoring=*Hypersensitivity reactions to carbamazepine have been reported in patients who previously experienced this reaction to anticonvulsants including phenytoin, primidone, and phenobarbital. If such history is present, benefits and risks should be carefully considered and, if carbamazepine is initiated, the signs and symptoms of hypersensitivity should be carefully monitored.
*Antiepileptic drugs (AEDs), including Tegretol, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
*Complete pretreatment blood counts, including platelets and possibly reticulocytes and serum iron, should be obtained as a baseline. If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely. Discontinuation of the drug should be considered if any evidence of significant bone marrow depression develops.
*Monitoring of blood levels (see CLINICAL PHARMACOLOGY) has increased the efficacy and safety of anticonvulsants. This monitoring may be particularly useful in cases of dramatic increase in seizure frequency and for verification of compliance. In addition, measurement of drug serum levels may aid in determining the cause of toxicity when more than one medication is being used.
*When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required.
*When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
:*When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced.
:*When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
:*The use of concomitant strong CYP3A4 inducers such as carbamazepine should be avoided with temsirolimus. If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered.
:*The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced.
:*Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS).
:*Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
*In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
*Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other non-depolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
|IVCompat=*There is limited information regarding <i>IV Compatibility</i> of {{PAGENAME}} in the drug label.
<!--Overdosage-->
|overdose='''Acute Toxicity'''
*Lowest known lethal dose: adults, 3.2 g (a 24-year-old woman died of a cardiac arrest and a 24-year-old man died of pneumonia and hypoxic encephalopathy); children, 4 g (a 14-year-old girl died of a cardiac arrest), 1.6 g (a 3-year-old girl died of aspiration pneumonia).
*Oral LD50 in animals (mg/kg): mice, 1100 to 3750; rats, 3850 to 4025; rabbits, 1500 to 2680; guinea pigs, 920.
'''Signs and Symptoms'''
*The first signs and symptoms appear after 1 to 3 hours. Neuromuscular disturbances are the most prominent. Cardiovascular disorders are generally milder, and severe cardiac complications occur only when very high doses (greater than 60 g) have been ingested.
*Cardiovascular System: Tachycardia, hypotension or hypertension, shock, conduction disorders.
*Nervous System and Muscles: Impairment of consciousness ranging in severity to deep coma. Convulsions, especially in small children. Motor restlessness, muscular twitching, tremor, athetoid movements, opisthotonos, ataxia, drowsiness, dizziness, mydriasis, nystagmus, adiadochokinesia, ballism, psychomotor disturbances, dysmetria. Initial hyperreflexia, followed by hyporeflexia.
*Gastrointestinal Tract: Nausea, vomiting.
*Kidneys and Bladder: Anuria or oliguria, urinary retention.
*Laboratory Findings: Isolated instances of overdosage have included leukocytosis, reduced leukocyte count, glycosuria, and acetonuria. EEG may show dysrhythmias.
*Combined Poisoning: When alcohol, tricyclic antidepressants, barbiturates, or hydantoins are taken at the same time, the signs and symptoms of acute poisoning with Tegretol may be aggravated or modified.
'''Treatment'''
*The prognosis in cases of severe poisoning is critically dependent upon prompt elimination of the drug, which may be achieved by inducing vomiting, irrigating the stomach, and by taking appropriate steps to diminish absorption. If these measures cannot be implemented without risk on the spot, the patient should be transferred at once to a hospital, while ensuring that vital functions are safeguarded. There is no specific antidote.
*Elimination of the Drug: Induction of vomiting.
*Gastric lavage. Even when more than 4 hours have elapsed following ingestion of the drug, the stomach should be repeatedly irrigated, especially if the patient has also consumed alcohol.
*Measures to Reduce Absorption: Activated charcoal, laxatives.
*Measures to Accelerate Elimination: Forced diuresis.
*Dialysis is indicated only in severe poisoning associated with renal failure. Replacement transfusion is indicated in severe poisoning in small children.
*Respiratory Depression: Keep the airways free; resort, if necessary, to endotracheal intubation, artificial respiration, and administration of oxygen.
*Hypotension, Shock: Keep the patient’s legs raised and administer a plasma expander. If blood pressure fails to rise despite measures taken to increase plasma volume, use of vasoactive substances should be considered.
*Convulsions: Diazepam or barbiturates.
*Warning: Diazepam or barbiturates may aggravate respiratory depression (especially in children), hypotension, and coma. However, barbiturates should not be used if drugs that inhibit monoamine oxidase have also been taken by the patient either in overdosage or in recent therapy (within 1 week).
*Surveillance: Respiration, cardiac function (ECG monitoring), blood pressure, body temperature, pupillary reflexes, and kidney and bladder function should be monitored for several days.
*Treatment of Blood Count Abnormalities: If evidence of significant bone marrow depression develops, the following recommendations are suggested: (1) stop the drug, (2) perform daily CBC, platelet, and reticulocyte counts, (3) do a bone marrow aspiration and trephine biopsy immediately and repeat with sufficient frequency to monitor recovery.
*Special periodic studies might be helpful as follows: (1) white cell and platelet antibodies, (2) 59Fe-ferrokinetic studies, (3) peripheral blood cell typing, (4) cytogenetic studies on marrow and peripheral blood, (5) bone marrow culture studies for colony-forming units, (6) hemoglobin electrophoresis for A2 and F hemoglobin, and (7) serum folic acid and B12 levels.
*A fully developed aplastic anemia will require appropriate, intensive monitoring and therapy, for which specialized consultation should be sought.
|drugBox=<!--Mechanism of Action-->
|mechAction=*Tegretol has demonstrated anticonvulsant properties in rats and mice with electrically and chemically induced seizures. It appears to act by reducing polysynaptic responses and blocking the post-tetanic potentiation. Tegretol greatly reduces or abolishes pain induced by stimulation of the infraorbital nerve in cats and rats. It depresses thalamic potential and bulbar and polysynaptic reflexes, including the linguomandibular reflex in cats. Tegretol is chemically unrelated to other anticonvulsants or other drugs used to control the pain of trigeminal neuralgia. The mechanism of action remains unknown.
*The principal metabolite of Tegretol, carbamazepine-10,11-epoxide, has anticonvulsant activity as demonstrated in several in vivo animal models of seizures. Though clinical activity for the epoxide has been postulated, the significance of its activity with respect to the safety and efficacy of Tegretol has not been established.
|structure=: [[File:{{PAGENAME}}01.png|thumb|none|600px|This image is provided by the National Library of Medicine.]]
* Tegretol, carbamazepine USP, is an anticonvulsant and specific analgesic for trigeminal neuralgia, available for oral administration as chewable tablets of 100 mg, tablets of 200 mg, XR tablets of 100, 200, and 400 mg, and as a suspension of 100 mg/5 mL (teaspoon). Its chemical name is 5H-dibenz[b,f ]azepine-5-carboxamide, and its structural formula is:
*Carbamazepine USP is a white to off-white powder, practically insoluble in water and soluble in alcohol and in acetone. Its molecular weight is 236.27.
|PD=There is limited information regarding <i>Pharmacodynamics</i> of {{PAGENAME}} in the drug label.
<!--Pharmacokinetics-->
|PK=*In clinical studies, Tegretol suspension, conventional tablets, and XR tablets delivered equivalent amounts of drug to the systemic circulation. However, the suspension was absorbed somewhat faster, and the XR tablet slightly slower, than the conventional tablet. The bioavailability of the XR tablet was 89% compared to suspension. Following a b.i.d. dosage regimen, the suspension provides higher peak levels and lower trough levels than those obtained from the conventional tablet for the same dosage regimen. On the other hand, following a t.i.d. dosage regimen, Tegretol suspension affords steady-state plasma levels comparable to Tegretol tablets given b.i.d. when administered at the same total mg daily dose. Following a b.i.d. dosage regimen, Tegretol-XR tablets afford steady-state plasma levels comparable to conventional Tegretol tablets given q.i.d., when administered at the same total mg daily dose. Tegretol in blood is 76% bound to plasma proteins. Plasma levels of Tegretol are variable and may range from 0.5 to 25 mcg/mL, with no apparent relationship to the daily intake of the drug. Usual adult therapeutic levels are between 4 and 12 mcg/mL. In polytherapy, the concentration of Tegretol and concomitant drugs may be increased or decreased during therapy, and drug effects may be altered (see PRECAUTIONS, Drug Interactions). Following chronic oral administration of suspension, plasma levels peak at approximately 1.5 hours compared to 4 to 5 hours after administration of conventional Tegretol tablets, and 3 to 12 hours after administration of Tegretol-XR tablets. The CSF/serum ratio is 0.22, similar to the 24% unbound Tegretol in serum. Because Tegretol induces its own metabolism, the half-life is also variable.
*Autoinduction is completed after 3 to 5 weeks of a fixed dosing regimen. Initial half-life values range from 25 to 65 hours, decreasing to 12 to 17 hours on repeated doses. Tegretol is metabolized in the liver. Cytochrome P450 3A4 was identified as the major isoform responsible for the formation of carbamazepine-10,11-epoxide from Tegretol. Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide. After oral administration of 14C-carbamazepine, 72% of the administered radioactivity was found in the urine and 28% in the feces. This urinary radioactivity was composed largely of hydroxylated and conjugated metabolites, with only 3% of unchanged Tegretol.
*The pharmacokinetic parameters of Tegretol disposition are similar in children and in adults. However, there is a poor correlation between plasma concentrations of carbamazepine and Tegretol dose in children. Carbamazepine is more rapidly metabolized to carbamazepine-10,11-epoxide (a metabolite shown to be equipotent to carbamazepine as an anticonvulsant in animal screens) in the younger age groups than in adults. In children below the age of 15, there is an inverse relationship between CBZ-E/CBZ ratio and increasing age (in one report from 0.44 in children below the age of 1 year to 0.18 in children between 10 to 15 years of age).
*The effects of race and gender on carbamazepine pharmacokinetics have not been systematically evaluated.
|nonClinToxic='''Carcinogenesis, Mutagenesis, Impairment of Fertility'''
*Carbamazepine, when administered to Sprague-Dawley rats for two years in the diet at doses of 25, 75, and 250 mg/kg/day, resulted in a dose-related increase in the incidence of hepatocellular tumors in females and of benign interstitial cell adenomas in the testes of males.
*Carbamazepine must, therefore, be considered to be carcinogenic in Sprague-Dawley rats. Bacterial and mammalian mutagenicity studies using carbamazepine produced negative results. The significance of these findings relative to the use of carbamazepine in humans is, at present, unknown.
|clinicalStudies=There is limited information regarding <i>Clinical Studies</i> of {{PAGENAME}} in the drug label.
<!--How Supplied-->
|howSupplied=Chewable Tablets 100 mg - round, red-speckled, pink, single-scored (imprinted Tegretol on one side and 52 twice on the scored side)
*Bottles of 100………………………………………………………………………………….NDC 0078-0492-05
*Unit Dose (blister pack)
*Box of 100 (strips of 10)……………………………………………………………………....NDC 0078-0492-35
*Do not store above 30°C (86°F). Protect from light and moisture.
*Dispense in tight, light-resistant container (USP).
*Meets USP Dissolution Test 1.
Tablets 200 mg - capsule-shaped, pink, single-scored (imprinted Tegretol on one side and 27 twice on the partially scored side)
*Bottles of 100.............................................................................................................................NDC 0078-0509-05
*Do not store above 30°C (86°F). Protect from moisture.
*Dispense in tight container (USP).
*Meets USP Dissolution Test 2.
XR Tablets 100 mg - round, yellow, coated (imprinted T on one side and 100 mg on the other), release portal on one side
*Bottles of 100.............................................................................................................................NDC 0078-0510-05
XR Tablets 200 mg - round, pink, coated (imprinted T on one side and 200 mg on the other), release portal on one side
*Bottles of 100.............................................................................................................................NDC 0078-0511-05
XR Tablets 400 mg - round, brown, coated (imprinted T on one side and 400 mg on the other), release portal on one side
*Bottles of 100.............................................................................................................................NDC 0078-0512-05
*Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) Protect from moisture.
*Dispense in tight container (USP).
Suspension 100 mg/5 mL (teaspoon) – yellow-orange, citrus-vanilla flavored
*Bottles of 450 mL.......................................................................................................................................NDC 0078-0508-83
*Shake well before using.
*Do not store above 30°C (86°F). Dispense in tight, light-resistant container (USP).
|storage=*Chewable Tablets 100 mg - round, red-speckled, pink, single-scored (imprinted Tegretol on one side and 52 twice on the scored side):
:*Do not store above 30°C (86°F). Protect from light and moisture.
:*Dispense in tight, light-resistant container (USP).
:*Meets USP Dissolution Test 1.
*Tablets 200 mg - capsule-shaped, pink, single-scored (imprinted Tegretol on one side and 27 twice on the partially scored side): Do not store above 30°C (86°F). Protect from moisture.
:*Dispense in tight container (USP).
:*Meets USP Dissolution Test 2.
==Trade names==
*XR Tablets 400 mg - round, brown, coated (imprinted T on one side and 400 mg on the other), release portal on one side: Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) Protect from moisture.
'''Carbamazepine''' has been sold under the names '''Tegretol''', '''Biston''', '''Calepsin''', '''Carbatrol''', '''Epitol''', '''Equetro''', '''Finlepsin''', '''Sirtal''', '''Stazepine''', '''Telesmin''', '''Timonil''', '''Trimonil''', '''Epimaz''', and '''Degranol''' (in [[South Africa]])<ref>http://www.intekom.com/pharm/lennon/degranol.html</ref>.
== History ==
:*Dispense in tight container (USP).
Carbamazepine was discovered by chemist Walter Schindler at J.R. Geigy AG (now part of [[Novartis]]) in [[Basel]], [[Switzerland]], in 1953.<ref>Schindler W, Häfliger F (1954). "Über Derivate des Iminodibenzyls". ''[[Helvetica Chimica Acta]]'' '''37''' (2): 472–483. {{doi|10.1002/hlca.19540370211}}.</ref> Schindler then synthesized the drug in 1960, before its anti-epileptic properties had been discovered.
Carbamazepine was first marketed as a drug to treat [[trigeminal neuralgia]] in 1962. It has been used as an anticonvulsant in the [[United Kingdom|UK]] since 1965, but only approved in the [[United States|U.S.]] since 1974.
*Suspension 100 mg/5 mL (teaspoon) – yellow-orange, citrus-vanilla flavored: Do not store above 30°C (86°F). Dispense in tight, light-resistant container (USP).
== Adverse effects ==
:*Thorazine® is a registered trademark of GlaxoSmithKline.
Carbamazepine renders certain methods of [[hormonal contraception]] ineffective because it is an enzyme inducer of the cytochrome P450 system which metabolises the oral contraceptive, leaving less active contraceptive in the plasma.
Common [[adverse drug reaction|side effect]]s include drowsiness, [[motor coordination]] impairment and/or upset stomach. Carbamazepine preparations can greatly decrease alcohol tolerance.
Less common side effects include cardiac arrhythmias, blurry or double [[Visual perception|vision]] and/or the temporary or mild loss of [[blood cell]]s or [[platelet]]s. In rare cases the latter can be life-threatening if unnoticed, so frequent blood tests are required during the first few months' use, followed by three or four tests per year. In the UK testing would be less frequent in long-term use, typically once every year or two. Underactivity of the thyroid gland may be provoked, so thyroid function tests are advisable every year or two.
*Patients should be informed of the availability of a Medication Guide and they should be instructed to read the Medication Guide before taking Tegretol.
Small reductions in white cell count and serum sodium are common.
*Patients should be made aware of the early toxic signs and symptoms of a potential hematologic problem, as well as dermatologic, hypersensitivity or hepatic reactions. These symptoms may include, but are not limited to, fever, sore throat, rash, ulcers in the mouth, easy bruising, lymphadenopathy and petechial or purpuric hemorrhage, and in the case of liver reactions, anorexia, nausea/vomiting, or jaundice. The patient should be advised that, because these signs and symptoms may signal a serious reaction, that they must report any occurrence immediately to a physician. In addition, the patient should be advised that these signs and symptoms should be reported even if mild or when occurring after extended use.
There are also reports of an auditory side effect, whereby patients perceive musical notes about a [[semitone]] lower than their actual pitch (so [[middle C]] would be heard as the note [[Scientific pitch notation|B3]] just below it, etc).
*Patients should be advised that serious skin reactions have been reported in association with Tegretol. In the event a skin reaction should occur while taking Tegretol, patients should consult with their physician immediately (see WARNINGS).
[[Oxcarbazepine]], a derivative of carbamazepine, has fewer and less serious side effects.
*Patients, their caregivers, and families should be counseled that AEDs, including Tegretol, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
Carbamazepine may cause [[Syndrome of inappropriate antidiuretic hormone|SIADH]] (syndrome of inappropriate antidiuretic hormone), since it both increases the release and potentiates the action of ADH ([[vasopressin]]).
*Tegretol may interact with some drugs. Therefore, patients should be advised to report to their doctors the use of any other prescription or nonprescription medications or herbal products.
Carbamazepine may aggravate [[juvenile myoclonic epilepsy]], so it is important to mention any history of jerking, especially in the morning, before starting to take this drug.
*Caution should be exercised if alcohol is taken in combination with Tegretol therapy, due to a possible additive sedative effect.
Pregnant women taking carbamazepine for seizures are putting their fetuses at increased risk for teratogenic effects and should be given [[folic acid]] supplementation and undergo prenatal ultrasonography for diagnosis.
*Since dizziness and drowsiness may occur, patients should be cautioned about the hazards of operating machinery or automobiles or engaging in other potentially dangerous tasks.
In addition, carbamazepine has been linked to serious adverse cognitive effects, including EEG slowing<ref>http://www.blackwell-synergy.com/doi/abs/10.1046/j.1528-1157.2002.22501.x</ref> and cell apoptosis<ref>http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=8719616&dopt=AbstractPlus</ref>.
*Patients should be encouraged to enroll in the NAAED Pregnancy Registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll free number 1-888-233-2334 (see WARNINGS, Usage in Pregnancy subsection).
The mechanism of action of carbamazepine and its derivatives is relatively well understood. Voltage-gated [[sodium channel]]s are the molecular pores that allow brain cells ([[neuron]]s) to generate [[action potential]]s, the electrical events that allow [[neuron]]s to communicate over long distances. After the sodium channels open, to start the action potential, they inactivate, essentially closing the channel. Carbamazepine stabilizes the inactivated state of sodium channels, meaning that fewer of these channels are available to open, making brain cells less excitable.
{{clear}}
|alcohol=*Caution should be exercised if alcohol is taken in combination with Tegretol therapy, due to a possible additive sedative effect.
== Interactions ==
*Combined Poisoning: When alcohol, tricyclic antidepressants, barbiturates, or hydantoins are taken at the same time, the signs and symptoms of acute poisoning with Tegretol may be aggravated or modified.
|brandNames=Carbatrol,
Epitol,
TEGretol,
TEGretol-XR,
Equetro.
|lookAlike=* A® — B®<ref name="www.ismp.org">{{Cite web | last = | first = | title = http://www.ismp.org | url = http://www.ismp.org | publisher = | date = }}</ref>
[[Valproic acid]] and [[valnoctamide]] both interact with carbamazepine, as they inhibit [[epoxide hydrolase|microsomal epoxide hydrolase]] (mEH), the [[enzyme]] responsible for the breakdown of carbamazepine-10,11 epoxide into inactive metabolites.<ref>{{cite book |last=Gonzalez |first=Frank J. |coauthors=Robert H. Tukey |editor=Laurence Brunton, John Lazo, Keith Parker (eds.) |title=[[Goodman & Gilman's The Pharmacological Basis of Therapeutics]] |edition=11<sup>th</sup> ed. |year=2006 |publisher=[[McGraw-Hill]] |location=New York |isbn=978-0071422802|pages=p. 79 |chapter=Drug Metabolism }}</ref> By inhibiting mEH, valproic acid and valnoctamide cause a buildup of the active metabolite, prolonging the effects of carbamazepine and delaying its excretion.
<!--Drug Shortage Status-->
|drugShortage=
}}
{{LabelImage
|fileName={{PAGENAME}}11.png
}}
{{LabelImage
|fileName={{PAGENAME}}11.png
}}
<!--Pill Image-->
Carbamazepine,as CYP 450 inducer, may increase clearance of many drugs, decreasing their blood levels.
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== See also ==
<!--Label Display Image-->
* [[Oxcarbazepine]]
== Notes ==
{{Reflist}}
== External links ==
* [http://www.carbatrol.com Carbatrol website]
* [http://www.equetro.com Equetro website]
* [http://www.rxlist.com/cgi/generic/carbam.htm TA warning]
* [http://www.psycheducation.org/depression/meds/carbamazepine.htm Carbamazepine overview] from PsychEducation.org
* [http://patimg1.uspto.gov/.piw?Docid=02948718&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%2Fnetahtml%2Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D2,948,718.WKU.%2526OS%3DPN%2F2,948,718%2526RS%3DPN%2F2,948,718&PageNum=&Rtype=&SectionNum=&idkey=2A0649DBED16 U.S. Patent 2,948,718, August 1960]
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Black Box Warning
WARNING: SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE & APLASTIC ANEMIA AND AGRANULOCYTOSIS
See full prescribing information for complete Boxed Warning.
SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE:
SERIOUS AND SOMETIMES FATAL DERMATOLOGIC REACTIONS, INCLUDING TOXIC EPIDERMAL NECROLYSIS (TEN) AND STEVENS-JOHNSON SYNDROME (SJS), HAVE BEEN REPORTED DURING TREATMENT WITH TEGRETOL. THESE REACTIONS ARE ESTIMATED TO OCCUR IN 1 TO 6 PER 10,000 NEW USERS IN COUNTRIES WITH MAINLY CAUCASIAN POPULATIONS, BUT THE RISK IN SOME ASIAN COUNTRIES IS ESTIMATED TO BE ABOUT 10 TIMES HIGHER. STUDIES IN PATIENTS OF CHINESE ANCESTRY HAVE FOUND A STRONG ASSOCIATION BETWEEN THE RISK OF DEVELOPING SJS/TEN AND THE PRESENCE OF HLA-B*1502, AN INHERITED ALLELIC VARIANT OF THE HLA-B GENE. HLA-B*1502 IS FOUND ALMOST EXCLUSIVELY IN PATIENTS WITH ANCESTRY ACROSS BROAD AREAS OF ASIA. PATIENTS WITH ANCESTRY IN GENETICALLY AT-RISK POPULATIONS SHOULD BE SCREENED FOR THE PRESENCE OF HLA-B*1502 PRIOR TO INITIATING TREATMENT WITH TEGRETOL. PATIENTS TESTING POSITIVE FOR THE ALLELE SHOULD NOT BE TREATED WITH TEGRETOL UNLESS THE BENEFIT CLEARLY OUTWEIGHS THE RISK (SEE WARNINGS AND PRECAUTIONS, LABORATORY TESTS).
APLASTIC ANEMIA AND AGRANULOCYTOSIS:
APLASTIC ANEMIA AND AGRANULOCYTOSIS HAVE BEEN REPORTED IN ASSOCIATION WITH THE USE OF TEGRETOL. DATA FROM A POPULATION-BASED CASE CONTROL STUDY DEMONSTRATE THAT THE RISK OF DEVELOPING THESE REACTIONS IS 5 TO 8 TIMES GREATER THAN IN THE GENERAL POPULATION. HOWEVER, THE OVERALL RISK OF THESE REACTIONS IN THE UNTREATED GENERAL POPULATION IS LOW, APPROXIMATELY SIX PATIENTS PER ONE MILLION POPULATION PER YEAR FOR AGRANULOCYTOSIS AND TWO PATIENTS PER ONE MILLION POPULATION PER YEAR FOR APLASTIC ANEMIA.
ALTHOUGH REPORTS OF TRANSIENT OR PERSISTENT DECREASED PLATELET OR WHITE BLOOD CELL COUNTS ARE NOT UNCOMMON IN ASSOCIATION WITH THE USE OF TEGRETOL, DATA ARE NOT AVAILABLE TO ESTIMATE ACCURATELY THEIR INCIDENCE OR OUTCOME. HOWEVER, THE VAST MAJORITY OF THE CASES OF LEUKOPENIA HAVE NOT PROGRESSED TO THE MORE SERIOUS CONDITIONS OF APLASTIC ANEMIA OR AGRANULOCYTOSIS.
BECAUSE OF THE VERY LOW INCIDENCE OF AGRANULOCYTOSIS AND APLASTIC ANEMIA, THE VAST MAJORITY OF MINOR HEMATOLOGIC CHANGES OBSERVED IN MONITORING OF PATIENTS ON TEGRETOL ARE UNLIKELY TO SIGNAL THE OCCURRENCE OF EITHER ABNORMALITY. NONETHELESS, COMPLETE PRETREATMENT HEMATOLOGICAL TESTING SHOULD BE OBTAINED AS A BASELINE. IF A PATIENT IN THE COURSE OF TREATMENT EXHIBITS LOW OR DECREASED WHITE BLOOD CELL OR PLATELET COUNTS, THE PATIENT SHOULD BE MONITORED CLOSELY. *DISCONTINUATION OF THE DRUG SHOULD BE CONSIDERED IF ANY EVIDENCE OF SIGNIFICANT BONE MARROW DEPRESSION DEVELOPS.
Tegretol is indicated for use as an anticonvulsant drug. Evidence supporting efficacy of Tegretol as an anticonvulsant was derived from active drug-controlled studies that enrolled patients with the following seizure types:
Partial seizures with complex symptomatology (psychomotor, temporal lobe). Patients with these seizures appear to show greater improvement than those with other types.
Mixed seizure patterns which include the above, or other partial or generalized seizures. Absence seizures (petit mal) do not appear to be controlled by Tegretol.
Dosing Information
Monitoring:
Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in adults. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
Combination Therapy:
When the patient is receiving existing anticonvulsant therapy, add carbamazepine gradually while the existing anticonvulsant is maintained or gradually decreased; the exception is phenytoin, which may need to be increased.
Suspension:
1) The recommended initial adult dose of carbamazepine oral suspension for seizure control is 100 mg orally 4 times daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1200 mg/day; rarely, up to 1600 mg/day has been used.
2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
Tablets or Chewable Tablets:
1) The recommended initial adult dose of carbamazepine immediate-release tablets or chewable tablets for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1200 mg/day; rarely, up to 1600 mg/day has been given.
Extended-release Tablets or Capsules:*
1) The recommended initial adult dose of carbamazepine extended-release tablets or capsules for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 2 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1200 mg/day; rarely, up to 1600 mg/day has been given.
Trigeminal Neuralgia
Tegretol is indicated in the treatment of the pain associated with true trigeminal neuralgia.
This drug is not a simple analgesic and should not be used for the relief of trivial aches or pains.
Dosing Information
a) The recommended initial dose for the treatment of trigeminal neuralgia is carbamazepine 200 mg/day given on day 1 as 50 mg ORALLY 4 times daily using oral suspension, as 100 mg orally twice daily using tablets (immediate-release, chewable tablets, or extended-release), or 200 mg once if using carbamazepine extended-release capsules. The dose may be increased by up to 200 mg/day using increments of 50 mg 4 times daily with oral suspension, increments of 100 mg every 12 hours for tablets (immediate-release, chewable tablets, or extended-release), or increments of 200 mg every 12 hours with extended-release capsules. Effective maintenance doses range from 200 to 1200 mg daily; for most patients the maintenance dose has been 400 to 800 mg/day. Do not exceed 1200 mg/day.
b) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
c) At least once every 3 months, attempts should be made to reduce the dose to the minimum effective dose or to discontinue the drug.
Bipolar I disorder, Acute manic or mixed episodes
Dosing information
a) The recommended initial dose for the treatment of adults with acute manic or mixed episodes associated with bipolar I disorder is 200 mg orally twice daily. The dose may be adjusted in increments of 200 mg/day to achieve the optimum clinical response; doses above 1600 mg/day have not been evaluated
b) The longer-term or prophylactic use of Equetro(R) capsules for the treatment of bipolar mania has not been studied. Physicians who choose to prescribe this medication for extended periods of time should re-evaluate the long-term risks and benefits of the drug for the individual patient at regular intervals.
c) Most patients with bipolar disorder have responded to carbamazepine 600 to 1600 mg/day administered in divided doses, although some patients have required doses as high as 2000 to 3000 mg/day. Rapid-cycling patients usually require higher doses of 1000 to 2000 mg daily.
1) When the patient is receiving existing anticonvulsant therapy, add carbamazepine gradually while the existing anticonvulsant is maintained or gradually decreased; the exception is phenytoin, which may need to be increased.
b) Under 6 Years of Age
1) Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in children. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
Suspension:
1) The recommended initial dose of carbamazepine oral suspension in children under 6 years of age for seizure control is 10 to 20 mg/kg/day orally in 4 divided doses. The dose may be increased at weekly intervals (maintenance usually below 35 mg/kg/day) to achieve clinical response or therapeutic plasma levels (4 to 12 mcg/mL). The safety of doses above 35 mg/kg is not established.
2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
3) Carbamazepine oral suspension was adequately absorbed from the gastrointestinal tract of newborns with a variety of seizure disorders. All infants were receiving other anticonvulsant agents in addition to carbamazepine. Maintenance therapy with carbamazepine doses of 5 to 8 mg/kg orally twice a day resulted in trough carbamazepine serum concentrations in the therapeutic range (10 to 40 mcmol/L). An elimination half-life ranging from 7.2 to 15.2 hours was observed; carbamazepine oral suspension may be useful for the treatment of neonatal seizures, and further study is required to evaluate its efficacy in this age group.
b) Tablets or Chewable Tablets:
1) The recommended initial dose of carbamazepine immediate-release tablets or chewable tablets in children under 6 years of age for seizure control is 10 to 20 mg/kg/day orally in 2 or 3 divided doses. The dose may be increased at weekly intervals (maintenance usually below 35 mg/kg/day) to achieve clinical response or therapeutic plasma levels (4 to 12 mcg/mL). The safety of doses above 35 mg/kg is not established.
2) In a review of dose-plasma concentration relationships in 196 children, usual pediatric dosage recommendations of 10 to 30 mg/kg/day were insufficient to achieve therapeutic serum concentrations in many patients, even those on monotherapy. Use of higher dosages requires careful evaluation of efficacy and potential toxicity.
c) 6 to 12 Years of Age
1) Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in children. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
a) Suspension:
1) The recommended initial dose of carbamazepine oral suspension in children 6 to 12 years of age for seizure control is 50 mg orally 4 times daily. The dose may be increased by adding up to 100 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 400 to 800 mg/day). Generally, do not exceed 1000 mg/day.
2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
b) Tablets or Chewable Tablets:
1) The recommended initial dose of carbamazepine immediate-release tablets or chewable tablets in children 6 to 12 years of age for seizure control is 100 mg orally twice daily. The dose may be increased by adding up to 100 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 400 to 800 mg/day). Generally, do not exceed 1000 mg/day.
c) Extended-release Capsules:
1) In patients under 12 years of age, extended-release capsules may be used if the patient is currently receiving immediate-release product at 400 mg/day or greater. The same dose of the extended-release capsule may be given in 2 divided doses.
d) Extended-release Tablets:
1) The recommended initial dose of carbamazepine extended-release tablets in children 6 to 12 years of age for seizure control is 100 mg orally twice daily. The dose may be increased by adding up to 100 mg/day in 2 divided doses at weekly intervals to the minimum effective level (usually 400 to 800 mg/day). Generally, do not exceed 1000 mg/day.
2) In a review of dose-plasma concentration relationships in 196 children, usual pediatric dosage recommendations of 10 to 30 mg/kg/day were insufficient to achieve therapeutic serum concentrations in many patients, even those on monotherapy. Use of higher dosages requires careful evaluation of efficacy and potential toxicity.
d) Over 12 years of Age
1) Monitoring blood levels of carbamazepine increases the efficacy and safety of administration. Dosage should be adjusted according to individual needs. The generally accepted therapeutic range of total carbamazepine in plasma is 4 to 12 mcg/mL in children. Following gradual increases to achieve seizure control, the dosage may be reduced gradually to minimum effective levels.
a) Suspension:
1) The recommended initial dose of carbamazepine oral suspension in adolescents over 12 years of age for seizure control is 100 mg orally 4 times daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1000 mg/day in adolescents 12 to 15 years of age or 1200 mg/day in adolescents older than 15 years.
2) Carbamazepine oral suspension will produce higher peak levels than the same dose given as a tablet; therefore, it is recommended that patients be initiated on lower doses and increased slowly to avoid adverse events.
b) Tablets or Chewable Tablets:
1) The recommended initial dose of carbamazepine immediate-release tablets or chewable tablets in adolescents over 12 years of age for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 3 or 4 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1000 mg/day in adolescents 12 to 15 years of age or 1200 mg/day in adolescents older than 15 years.
c) Extended-release Tablets or Capsules:
1) The recommended initial dose of carbamazepine extended-release tablets or capsules in adolescents over 12 years of age for seizure control is 200 mg orally twice daily for the first week. The dose may be increased by adding up to 200 mg/day in 2 divided doses at weekly intervals to the minimum effective level (usually 800 to 1200 mg/day). Generally, do not exceed 1000 mg/day in adolescents 12 to 15 years of age or 1200 mg/day in adolescents older than 15 years.
2) In a review of dose-plasma concentration relationships in 196 children, usual pediatric dosage recommendations of 10 to 30 mg/kg/day were insufficient to achieve therapeutic serum concentrations in many patients, even those on monotherapy. Use of higher dosages requires careful evaluation of efficacy and potential toxicity.
The safety and effectiveness of Equitro(R) are not established in pediatric and adolescent patients.
Withdrawal Of Therapy
When carbamazepine therapy is to be discontinued, gradually taper to minimize the possibility of increased seizure frequency.
Withdrawal of anticonvulsant medication in children free of seizures for 2 to 4 years appears to be safe, with the majority of children remaining free of seizures after medication withdrawal. In a prospective study, anticonvulsant medications were discontinued in 88 epileptic children who had not had a seizure for 2 to 4 years. :*Anticonvulsants were withdrawn gradually over 2 to 3 months. The mean age at the time of the first seizure was 5 years (range, 0 to 16 years), with the mean age at the time of the last seizure being 8.7 years (range, to 22 years). The mean duration of seizures was 3.7 years (range, 0 to 17.4 years). Sixty-six (75%) patients remained free of seizures after withdrawal of anticonvulsants, and the overall probability of remaining seizure-free was 79% at 12 months, 77% at 24 months, and 74% at 30 months. The risk of recurrence of seizures was highest within the first few months of initiation of withdrawal. Of 22 patients with recurrence of seizures, 9 occurred within the first 3 months, 13 in the first 6 months, and 18 (82%) within the first year of withdrawal. The type of seizure, age at onset, and EEG characteristics were considered important in predicting the outcome of anticonvulsant withdrawal. It is recommended that anticonvulsants be discontinued in children with good prognostic factors after a 2-year period without seizures.
Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Carbamazepine in pediatric patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Carbamazepine in pediatric patients.
Contraindications
Tegretol should not be used in patients with a history of previous bone marrow depression, hypersensitivity to the drug, or known sensitivity to any of the tricyclic compounds, such as amitriptyline, desipramine, imipramine, protriptyline, nortriptyline, etc. Likewise, on theoretical grounds its use with monoamine oxidase (MAO) inhibitors is not recommended. Before administration of Tegretol, MAO inhibitors should be discontinued for a minimum of 14 days, or longer if the clinical situation permits.
Coadministration of carbamazepine and nefazodone may result in insufficient plasma concentrations of nefazodone and its active metabolite to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated.
Warnings
WARNING: SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE & APLASTIC ANEMIA AND AGRANULOCYTOSIS
See full prescribing information for complete Boxed Warning.
SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE:
SERIOUS AND SOMETIMES FATAL DERMATOLOGIC REACTIONS, INCLUDING TOXIC EPIDERMAL NECROLYSIS (TEN) AND STEVENS-JOHNSON SYNDROME (SJS), HAVE BEEN REPORTED DURING TREATMENT WITH TEGRETOL. THESE REACTIONS ARE ESTIMATED TO OCCUR IN 1 TO 6 PER 10,000 NEW USERS IN COUNTRIES WITH MAINLY CAUCASIAN POPULATIONS, BUT THE RISK IN SOME ASIAN COUNTRIES IS ESTIMATED TO BE ABOUT 10 TIMES HIGHER. STUDIES IN PATIENTS OF CHINESE ANCESTRY HAVE FOUND A STRONG ASSOCIATION BETWEEN THE RISK OF DEVELOPING SJS/TEN AND THE PRESENCE OF HLA-B*1502, AN INHERITED ALLELIC VARIANT OF THE HLA-B GENE. HLA-B*1502 IS FOUND ALMOST EXCLUSIVELY IN PATIENTS WITH ANCESTRY ACROSS BROAD AREAS OF ASIA. PATIENTS WITH ANCESTRY IN GENETICALLY AT-RISK POPULATIONS SHOULD BE SCREENED FOR THE PRESENCE OF HLA-B*1502 PRIOR TO INITIATING TREATMENT WITH TEGRETOL. PATIENTS TESTING POSITIVE FOR THE ALLELE SHOULD NOT BE TREATED WITH TEGRETOL UNLESS THE BENEFIT CLEARLY OUTWEIGHS THE RISK (SEE WARNINGS AND PRECAUTIONS, LABORATORY TESTS).
APLASTIC ANEMIA AND AGRANULOCYTOSIS:
APLASTIC ANEMIA AND AGRANULOCYTOSIS HAVE BEEN REPORTED IN ASSOCIATION WITH THE USE OF TEGRETOL. DATA FROM A POPULATION-BASED CASE CONTROL STUDY DEMONSTRATE THAT THE RISK OF DEVELOPING THESE REACTIONS IS 5 TO 8 TIMES GREATER THAN IN THE GENERAL POPULATION. HOWEVER, THE OVERALL RISK OF THESE REACTIONS IN THE UNTREATED GENERAL POPULATION IS LOW, APPROXIMATELY SIX PATIENTS PER ONE MILLION POPULATION PER YEAR FOR AGRANULOCYTOSIS AND TWO PATIENTS PER ONE MILLION POPULATION PER YEAR FOR APLASTIC ANEMIA.
ALTHOUGH REPORTS OF TRANSIENT OR PERSISTENT DECREASED PLATELET OR WHITE BLOOD CELL COUNTS ARE NOT UNCOMMON IN ASSOCIATION WITH THE USE OF TEGRETOL, DATA ARE NOT AVAILABLE TO ESTIMATE ACCURATELY THEIR INCIDENCE OR OUTCOME. HOWEVER, THE VAST MAJORITY OF THE CASES OF LEUKOPENIA HAVE NOT PROGRESSED TO THE MORE SERIOUS CONDITIONS OF APLASTIC ANEMIA OR AGRANULOCYTOSIS.
BECAUSE OF THE VERY LOW INCIDENCE OF AGRANULOCYTOSIS AND APLASTIC ANEMIA, THE VAST MAJORITY OF MINOR HEMATOLOGIC CHANGES OBSERVED IN MONITORING OF PATIENTS ON TEGRETOL ARE UNLIKELY TO SIGNAL THE OCCURRENCE OF EITHER ABNORMALITY. NONETHELESS, COMPLETE PRETREATMENT HEMATOLOGICAL TESTING SHOULD BE OBTAINED AS A BASELINE. IF A PATIENT IN THE COURSE OF TREATMENT EXHIBITS LOW OR DECREASED WHITE BLOOD CELL OR PLATELET COUNTS, THE PATIENT SHOULD BE MONITORED CLOSELY. *DISCONTINUATION OF THE DRUG SHOULD BE CONSIDERED IF ANY EVIDENCE OF SIGNIFICANT BONE MARROW DEPRESSION DEVELOPS.
Serious Dermatologic Reactions
Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), have been reported with Tegretol treatment. The risk of these events is estimated to be about 1 to 6 per 10,000 new users in countries with mainly Caucasian populations. However, the risk in some Asian countries is estimated to be about 10 times higher. Tegretol should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed and alternative therapy should be considered.
SJS/TEN and HLA-B*1502 Allele
Retrospective case-control studies have found that in patients of Chinese ancestry there is a strong association between the risk of developing SJS/TEN with carbamazepine treatment and the presence of an inherited variant of the HLA-B gene, HLA-B*1502. The occurrence of higher rates of these reactions in countries with higher frequencies of this allele suggests that the risk may be increased in allele-positive individuals of any ethnicity.
Across Asian populations, notable variation exists in the prevalence of HLA-B*1502. Greater than 15% of the population is reported positive in Hong Kong, Thailand, Malaysia, and parts of the Philippines, compared to about 10% in Taiwan and 4% in North China. South Asians, including Indians, appear to have intermediate prevalence of HLA-B*1502, averaging 2% to 4%, but higher in some groups. HLA-B*1502 is present in less than 1% of the population in Japan and Korea.
HLA-B*1502 is largely absent in individuals not of Asian origin (e.g., Caucasians, African-Americans, Hispanics, and Native Americans).
Prior to initiating Tegretol therapy, testing for HLA-B*1502 should be performed in patients with ancestry in populations in which HLA-B*1502 may be present. In deciding which patients to screen, the rates provided above for the prevalence of HLA-B*1502 may offer a rough guide, keeping in mind the limitations of these figures due to wide variability in rates even within ethnic groups, the difficulty in ascertaining ethnic ancestry, and the likelihood of mixed ancestry. Tegretol should not be used in patients positive for HLA-B*1502 unless the benefits clearly outweigh the risks. Tested patients who are found to be negative for the allele are thought to have a low risk of SJS/TEN (see BOXED WARNING and PRECAUTIONS, Laboratory Tests).
Over 90% of Tegretol treated patients who will experience SJS/TEN have this reaction within the first few months of treatment. This information may be taken into consideration in determining the need for screening of genetically at-risk patients currently on Tegretol.
The HLA-B*1502 allele has not been found to predict risk of less severe adverse cutaneous reactions from Tegretol such as maculopapular eruption (MPE) or to predict Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).
Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Chinese ancestry taking other antiepileptic drugs associated with SJS/TEN, including phenytoin. Consideration should be given to avoiding use of other drugs associated with SJS/TEN in HLA-B*1502 positive patients, when alternative therapies are otherwise equally acceptable.
Hypersensitivity Reactions and HLA-A*3101 Allele
Retrospective case-control studies in patients of European, Korean, and Japanese ancestry have found a moderate association between the risk of developing hypersensitivity reactions and the presence of HLA-A*3101, an inherited allelic variant of the HLA-A gene, in patients using carbamazepine. These hypersensitivity reactions include SJS/TEN, maculopapular eruptions, and Drug Reaction with Eosinophilia and Systemic Symptoms (see DRESS/Multiorgan hypersensitivity below).
HLA-A*3101 is expected to be carried by more than 15% of patients of Japanese, Native American, Southern Indian (for example, Tamil Nadu) and some Arabic ancestry; up to about 10% in patients of Han Chinese, Korean, European, Latin American, and other Indian ancestry; and up to about 5% in African-Americans and patients of Thai, Taiwanese, and Chinese (Hong Kong) ancestry.
The risks and benefits of Tegretol therapy should be weighed before considering Tegretol in patients known to be positive for HLA-A*3101.
Application of HLA genotyping as a screening tool has important limitations and must never substitute for appropriate clinical vigilance and patient management. Many HLA-B*1502-positive and HLA-A*3101-positive patients treated with Tegretol will not develop SJS/TEN or other hypersensitivity reactions, and these reactions can still occur infrequently in HLA-B*1502-negative and HLA-A*3101-negative patients of any ethnicity. The role of other possible factors in the development of, and morbidity from, SJS/TEN and other hypersensitivity reactions, such as antiepileptic drug (AED) dose, compliance, concomitant medications, comorbidities, and the level of dermatologic monitoring, have not been studied.
Aplastic Anemia and Agranulocytosis
Aplastic anemia and agranulocytosis have been reported in association with the use of TEGRETOL (see BOXED WARNING). Patients with a history of adverse hematologic reaction to any drug may be particularly at risk of bone marrow depression.
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), also known as multiorgan hypersensitivity, has occurred with Tegretol. Some of these events have been fatal or life-threatening. DRESS typically, although not exclusively, presents with fever, rash, and/or lymphadenopathy, in association with other organ system involvement, such as hepatitis, nephritis, hematologic abnormalities, myocarditis, or myositis sometimes resembling an acute viral infection. Eosinophilia is often present. This disorder is variable in its expression, and other organ systems not noted here may be involved. It is important to note that early manifestations of hypersensitivity (e.g., fever, lymphadenopathy) may be present even though rash is not evident. If such signs or symptoms are present, the patient should be evaluated immediately. Tegretol should be discontinued if an alternative etiology for the signs or symptoms cannot be established.
Hypersensitivity
Hypersensitivity reactions to carbamazepine have been reported in patients who previously experienced this reaction to anticonvulsants including phenytoin, primidone, and phenobarbital. If such history is present, benefits and risks should be carefully considered and, if carbamazepine is initiated, the signs and symptoms of hypersensitivity should be carefully monitored.
In patients who have exhibited hypersensitivity reactions to carbamazepine, approximately 25 to 30% may experience hypersensitivity reactions with oxcarbazepine (Trileptal®).
Suicidal Behavior and Ideation
Antiepileptic drugs (AEDs), including Tegretol, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.
The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5 to 100 years) in the clinical trials analyzed. Table 1 shows absolute and relative risk by indication for all evaluated AEDs.
The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
Anyone considering prescribing Tegretol or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
General
Tegretol has shown mild anticholinergic activity; therefore, patients with increased intraocular pressure should be closely observed during therapy.
Because of the relationship of the drug to other tricyclic compounds, the possibility of activation of a latent psychosis and, in elderly patients, of confusion or agitation should be borne in mind.
The use of Tegretol should be avoided in patients with a history of hepatic porphyria (e.g., acute intermittent porphyria, variegate porphyria, porphyria cutanea tarda). Acute attacks have been reported in such patients receiving Tegretol therapy. Carbamazepine administration has also been demonstrated to increase porphyrin precursors in rodents, a presumed mechanism for the induction of acute attacks of porphyria.
As with all antiepileptic drugs, Tegretol should be withdrawn gradually to minimize the potential of increased seizure frequency.
Usage in Pregnancy
Carbamazepine can cause fetal harm when administered to a pregnant woman.
Epidemiological data suggest that there may be an association between the use of carbamazepine during pregnancy and congenital malformations, including spina bifida. There have also been reports that associate carbamazepine with developmental disorders and congenital anomalies (e.g., craniofacial defects, cardiovascular malformations, hypospadias, and anomalies involving various body systems). Developmental delays based on neurobehavioral assessments have been reported. When treating or counseling women of childbearing potential, the prescribing physician will wish to weigh the benefits of therapy against the risks. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
Retrospective case reviews suggest that, compared with monotherapy, there may be a higher prevalence of teratogenic effects associated with the use of anticonvulsants in combination therapy. Therefore, if therapy is to be continued, monotherapy may be preferable for pregnant women.
In humans, transplacental passage of carbamazepine is rapid (30 to 60 minutes), and the drug is accumulated in the fetal tissues, with higher levels found in liver and kidney than in brain and lung.
Carbamazepine has been shown to have adverse effects in reproduction studies in rats when given orally in dosages 10 to 25 times the maximum human daily dosage (MHDD) of 1200 mg on a mg/kg basis or 1.5 to 4 times the MHDD on a mg/m2 basis. In rat teratology studies, 2 of 135 offspring showed kinked ribs at 250 mg/kg and 4 of 119 offspring at 650 mg/kg showed other anomalies (cleft palate, 1; talipes, 1; anophthalmos, 2). In reproduction studies in rats, nursing offspring demonstrated a lack of weight gain and an unkempt appearance at a maternal dosage level of 200 mg/kg.
Antiepileptic drugs should not be discontinued abruptly in patients in whom the drug is administered to prevent major seizures because of the strong possibility of precipitating status epilepticus with attendant hypoxia and threat to life. In individual cases where the severity and frequency of the seizure disorder are such that removal of medication does not pose a serious threat to the patient, discontinuation of the drug may be considered prior to and during pregnancy, although it cannot be said with any confidence that even minor seizures do not pose some hazard to the developing embryo or fetus.
Tests to detect defects using currently accepted procedures should be considered a part of routine prenatal care in childbearing women receiving carbamazepine.
There have been a few cases of neonatal seizures and/or respiratory depression associated with maternal Tegretol and other concomitant anticonvulsant drug use. A few cases of neonatal vomiting, diarrhea, and/or decreased feeding have also been reported in association with maternal Tegretol use. These symptoms may represent a neonatal withdrawal syndrome.
To provide information regarding the effects of in utero exposure to Tegretol, physicians are advised to recommend that pregnant patients taking Tegretol enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.
PRECAUTIONS
General
Before initiating therapy, a detailed history and physical examination should be made.
Tegretol should be used with caution in patients with a mixed seizure disorder that includes atypical absence seizures, since in these patients Tegretol has been associated with increased frequency of generalized convulsions.
Therapy should be prescribed only after critical benefit-to-risk appraisal in patients with a history of cardiac conduction disturbance, including second- and third-degree AV heart block; cardiac, hepatic, or renal damage; adverse hematologic or hypersensitivity reaction to other drugs, including reactions to other anticonvulsants; or interrupted courses of therapy with Tegretol.
AV heart block, including second- and third-degree block, have been reported following Tegretol treatment. This occurred generally, but not solely, in patients with underlying EKG abnormalities or risk factors for conduction disturbances.
Hepatic effects, ranging from slight elevations in liver enzymes to rare cases of hepatic failure have been reported (see ADVERSE REACTIONS and PRECAUTIONS, Laboratory Tests). In some cases, hepatic effects may progress despite discontinuation of the drug. In addition rare instances of vanishing bile duct syndrome have been reported. This syndrome consists of a cholestatic process with a variable clinical course ranging from fulminant to indolent, involving the destruction and disappearance of the intrahepatic bile ducts. Some, but not all, cases are associated with features that overlap with other immunoallergenic syndromes such as multiorgan hypersensitivity (DRESS syndrome) and serious dermatologic reactions. As an example there has been a report of vanishing bile duct syndrome associated with Stevens-Johnson syndrome and in another case an association with fever and eosinophilia.
Since a given dose of Tegretol suspension will produce higher peak levels than the same dose given as the tablet, it is recommended that patients given the suspension be started on lower doses and increased slowly to avoid unwanted side effects.
Tegretol suspension contains sorbitol and, therefore, should not be administered to patients with rare hereditary problems of fructose intolerance.
Laboratory Tests
For genetically at-risk patients (see WARNINGS), high-resolution ‘HLA-B*1502 typing’ is recommended. The test is positive if either one or two HLA-B*1502 alleles are detected and negative if no HLA-B*1502 alleles are detected.
Complete pretreatment blood counts, including platelets and possibly reticulocytes and serum iron, should be obtained as a baseline. If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely. Discontinuation of the drug should be considered if any evidence of significant bone marrow depression develops.
Baseline and periodic evaluations of liver function, particularly in patients with a history of liver disease, must be performed during treatment with this drug since liver damage may occur. Carbamazepine should be discontinued, based on clinical judgment, if indicated by newly occurring or worsening clinical or laboratory evidence of liver dysfunction or hepatic damage, or in the case of active liver disease.
Baseline and periodic eye examinations, including slit-lamp, funduscopy, and tonometry, are recommended since many phenothiazines and related drugs have been shown to cause eye changes.
Baseline and periodic complete urinalysis and BUN determinations are recommended for patients treated with this agent because of observed renal dysfunction.
Monitoring of blood levels has increased the efficacy and safety of anticonvulsants. This monitoring may be particularly useful in cases of dramatic increase in seizure frequency and for verification of compliance. In addition, measurement of drug serum levels may aid in determining the cause of toxicity when more than one medication is being used.
Thyroid function tests have been reported to show decreased values with Tegretol administered alone.
Hyponatremia has been reported in association with Tegretol use, either alone or in combination with other drugs.
Interference with some pregnancy tests has been reported.
Drug Interactions
There has been a report of a patient who passed an orange rubbery precipitate in his stool the day after ingesting Tegretol suspension immediately followed by Thorazine®* solution. Subsequent testing has shown that mixing Tegretol suspension and chlorpromazine solution (both generic and brand name) as well as Tegretol suspension and liquid Mellaril®, resulted in the occurrence of this precipitate. Because the extent to which this occurs with other liquid medications is not known, Tegretol suspension should not be administered simultaneously with other liquid medicinal agents or diluents.
Clinically meaningful drug interactions have occurred with concomitant medications and include (but are not limited to) the following:
Agents That May Affect Tegretol Plasma Levels
When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required.
Agents That Increase Carbamazepine Levels
CYP3A4 inhibitors inhibit Tegretol metabolism and can thus increase plasma carbamazepine levels. Drugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides, erythromycin, troleandomycin, clarithromycin, fluoxetine, fluvoxamine, trazodone, olanzapine, loratadine, terfenadine, omeprazole, oxybutynin, dantrolene, isoniazid, niacinamide, nicotinamide, ibuprofen, propoxyphene, azoles (e.g., ketaconazole, itraconazole, fluconazole, voriconazole), acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors.
Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide. Coadministration of inhibitors of human microsomal epoxide hydrolase may result in increased carbamazepine-10,11 epoxide plasma concentrations. Accordingly, the dosage of Tegretol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, or valproic acid.
Effect of Tegretol on Plasma Levels of Concomitant Agents
Decreased Levels of Concomitant Medications
Tegretol is a potent inducer of hepatic 3A4 and is also known to be an inducer of CYP1A2, 2B6, 2C9/19 and may therefore reduce plasma concentrations of co-medications mainly metabolized by CYP 1A2, 2B6, 2C9/19 and 3A4, through induction of their metabolism. When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced.
When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
The use of concomitant strong CYP3A4 inducers such as carbamazepine should be avoided with temsirolimus. If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered.
The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced.
Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS).
Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
Other Drug Interactions
Cyclophosphamide is an inactive prodrug and is converted to its active metabolite in part by CYP3A. The rate of metabolism and the leukopenic activity of cyclophosphamide are reportedly increased by chronic coadministration of CYP3A4 inducers. There is a potential for increased cyclophosphamide toxicity when coadministered with carbamazepine.
Concomitant administration of carbamazepine and lithium may increase the risk of neurotoxic side effects.
Concomitant use of carbamazepine and isoniazid has been reported to increase isoniazid-induced hepatotoxicity.
Concomitant medication with Tegretol and some diuretics (e.g., hydrochlorothiazide, furosemide) may lead to symptomatic hyponatremia.
Alterations of thyroid function have been reported in combination therapy with other anticonvulsant medications.
Concomitant use of Tegretol with hormonal contraceptive products (e.g., oral, and levonorgestrel subdermal implant contraceptives) may render the contraceptives less effective because the plasma concentrations of the hormones may be decreased. Breakthrough bleeding and unintended pregnancies have been reported. Alternative or back-up methods of contraception should be considered.
Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other non-depolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
Adverse Reactions
Clinical Trials Experience
If adverse reactions are of such severity that the drug must be discontinued, the physician must be aware that abrupt discontinuation of any anticonvulsant drug in a responsive epileptic patient may lead to seizures or even status epilepticus with its life-threatening hazards.
The most severe adverse reactions have been observed in the hemopoietic system and skin (see BOXED WARNING), the liver, and the cardiovascular system.
The most frequently observed adverse reactions, particularly during the initial phases of therapy, are dizziness, drowsiness, unsteadiness, nausea, and vomiting. To minimize the possibility of such reactions, therapy should be initiated at the lowest dosage recommended.
The following additional adverse reactions have been reported:
Genitourinary System: Urinary frequency, acute urinary retention, oliguria with elevated blood pressure, azotemia, renal failure, and impotence. Albuminuria, glycosuria, elevated BUN, and microscopic deposits in the urine have also been reported. There have been very rare reports of impaired male fertility and/or abnormal spermatogenesis.
Testicular atrophy occurred in rats receiving Tegretol orally from 4 to 52 weeks at dosage levels of 50 to 400 mg/kg/day. Additionally, rats receiving Tegretol in the diet for 2 years at dosage levels of 25, 75, and 250 mg/kg/day had a dose-related incidence of testicular atrophy and aspermatogenesis. In dogs, it produced a brownish discoloration, presumably a metabolite, in the urinary bladder at dosage levels of 50 mg/kg and higher. Relevance of these findings to humans is unknown.
There have been reports of associated paralysis and other symptoms of cerebral arterial insufficiency, but the exact relationship of these reactions to the drug has not been established.
Isolated cases of neuroleptic malignant syndrome have been reported both with and without concomitant use of psychotropic drugs.
Digestive System: Nausea, vomiting, gastric distress and abdominal pain, diarrhea, constipation, anorexia, and dryness of the mouth and pharynx, including glossitis and stomatitis.
Eyes: Scattered punctate cortical lens opacities, increased intraocular pressure as well as conjunctivitis, have been reported. Although a direct causal relationship has not been established, many phenothiazines and related drugs have been shown to cause eye changes.
Musculoskeletal System: Aching joints and muscles, and leg cramps.
Metabolism: Fever and chills. Inappropriate antidiuretic hormone (ADH) secretion syndrome has been reported. Cases of frank water intoxication, with decreased serum sodium (hyponatremia) and confusion, have been reported in association with Tegretol use. Decreased levels of plasma calcium leading to osteoporosis have been reported.
Isolated cases of a lupus erythematosus-like syndrome have been reported. There have been occasional reports of elevated levels of cholesterol, HDL cholesterol, and triglycerides in patients taking anticonvulsants.
A case of aseptic meningitis, accompanied by myoclonus and peripheral eosinophilia, has been reported in a patient taking carbamazepine in combination with other medications. The patient was successfully dechallenged, and the meningitis reappeared upon rechallenge with carbamazepine.
DRUG ABUSE AND DEPENDENCE
No evidence of abuse potential has been associated with Tegretol, nor is there evidence of psychological or physical dependence in humans.
Postmarketing Experience
There is limited information regarding Postmarketing Experience of Carbamazepine in the drug label.
Drug Interactions
There has been a report of a patient who passed an orange rubbery precipitate in his stool the day after ingesting Tegretol suspension immediately followed by Thorazine®* solution. Subsequent testing has shown that mixing Tegretol suspension and chlorpromazine solution (both generic and brand name) as well as Tegretol suspension and liquid Mellaril®, resulted in the occurrence of this precipitate. Because the extent to which this occurs with other liquid medications is not known, Tegretol suspension should not be administered simultaneously with other liquid medicinal agents or diluents.
Clinically meaningful drug interactions have occurred with concomitant medications and include (but are not limited to) the following:
Agents That May Affect Tegretol Plasma Levels
When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required.
Agents That Increase Carbamazepine Levels
CYP3A4 inhibitors inhibit Tegretol metabolism and can thus increase plasma carbamazepine levels. Drugs that have been shown, or would be expected, to increase plasma carbamazepine levels include aprepitant, cimetidine, ciprofloxacin, danazol, diltiazem, macrolides, erythromycin, troleandomycin, clarithromycin, fluoxetine, fluvoxamine, trazodone, olanzapine, loratadine, terfenadine, omeprazole, oxybutynin, dantrolene, isoniazid, niacinamide, nicotinamide, ibuprofen, propoxyphene, azoles (e.g., ketaconazole, itraconazole, fluconazole, voriconazole), acetazolamide, verapamil, ticlopidine, grapefruit juice, and protease inhibitors.
Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide. Coadministration of inhibitors of human microsomal epoxide hydrolase may result in increased carbamazepine-10,11 epoxide plasma concentrations. Accordingly, the dosage of Tegretol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, or valproic acid.
Effect of Tegretol on Plasma Levels of Concomitant Agents
Decreased Levels of Concomitant Medications
Tegretol is a potent inducer of hepatic 3A4 and is also known to be an inducer of CYP1A2, 2B6, 2C9/19 and may therefore reduce plasma concentrations of co-medications mainly metabolized by CYP 1A2, 2B6, 2C9/19 and 3A4, through induction of their metabolism. When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced.
When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
The use of concomitant strong CYP3A4 inducers such as carbamazepine should be avoided with temsirolimus. If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered.
The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced.
Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS).
Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
Other Drug Interactions
Cyclophosphamide is an inactive prodrug and is converted to its active metabolite in part by CYP3A. The rate of metabolism and the leukopenic activity of cyclophosphamide are reportedly increased by chronic coadministration of CYP3A4 inducers. There is a potential for increased cyclophosphamide toxicity when coadministered with carbamazepine.
Concomitant administration of carbamazepine and lithium may increase the risk of neurotoxic side effects.
Concomitant use of carbamazepine and isoniazid has been reported to increase isoniazid-induced hepatotoxicity.
Concomitant medication with Tegretol and some diuretics (e.g., hydrochlorothiazide, furosemide) may lead to symptomatic hyponatremia.
Alterations of thyroid function have been reported in combination therapy with other anticonvulsant medications.
Concomitant use of Tegretol with hormonal contraceptive products (e.g., oral, and levonorgestrel subdermal implant contraceptives) may render the contraceptives less effective because the plasma concentrations of the hormones may be decreased. Breakthrough bleeding and unintended pregnancies have been reported. Alternative or back-up methods of contraception should be considered.
Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other non-depolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
Carbamazepine can cause fetal harm when administered to a pregnant woman.
Epidemiological data suggest that there may be an association between the use of carbamazepine during pregnancy and congenital malformations, including spina bifida. There have also been reports that associate carbamazepine with developmental disorders and congenital anomalies (e.g., craniofacial defects, cardiovascular malformations, hypospadias, and anomalies involving various body systems). Developmental delays based on neurobehavioral assessments have been reported. When treating or counseling women of childbearing potential, the prescribing physician will wish to weigh the benefits of therapy against the risks. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.
Retrospective case reviews suggest that, compared with monotherapy, there may be a higher prevalence of teratogenic effects associated with the use of anticonvulsants in combination therapy. Therefore, if therapy is to be continued, monotherapy may be preferable for pregnant women.
In humans, transplacental passage of carbamazepine is rapid (30 to 60 minutes), and the drug is accumulated in the fetal tissues, with higher levels found in liver and kidney than in brain and lung.
Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Carbamazepine in women who are pregnant.
Labor and Delivery
The effect of Tegretol on human labor and delivery is unknown.
Nursing Mothers
Tegretol and its epoxide metabolite are transferred to breast milk. The ratio of the concentration in breast milk to that in maternal plasma is about 0.4 for Tegretol and about 0.5 for the epoxide. The estimated doses given to the newborn during breastfeeding are in the range of 2 to 5 mg daily for Tegretol and 1 to 2 mg daily for the epoxide.
Because of the potential for serious adverse reactions in nursing infants from carbamazepine, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Pediatric Use
Substantial evidence of Tegretol’s effectiveness for use in the management of children with epilepsy is derived from clinical investigations performed in adults and from studies in several in vitro systems which support the conclusion that (1) the pathogenetic mechanisms underlying seizure propagation are essentially identical in adults and children, and (2) the mechanism of action of carbamazepine in treating seizures is essentially identical in adults and children.
Taken as a whole, this information supports a conclusion that the generally accepted therapeutic range of total carbamazepine in plasma (i.e. 4 to 12 mcg/mL) is the same in children and adults.
The evidence assembled was primarily obtained from short-term use of carbamazepine. The safety of carbamazepine in children has been systematically studied up to 6 months. No longer-term data from clinical trials is available.
Geriatic Use
No systematic studies in geriatric patients have been conducted.
Gender
There is no FDA guidance on the use of Carbamazepine with respect to specific gender populations.
Race
There is no FDA guidance on the use of Carbamazepine with respect to specific racial populations.
Renal Impairment
There is no FDA guidance on the use of Carbamazepine in patients with renal impairment.
Hepatic Impairment
There is no FDA guidance on the use of Carbamazepine in patients with hepatic impairment.
Females of Reproductive Potential and Males
There is no FDA guidance on the use of Carbamazepine in women of reproductive potentials and males.
Immunocompromised Patients
There is no FDA guidance one the use of Carbamazepine in patients who are immunocompromised.
Administration and Monitoring
Administration
Tegretol suspension in combination with liquid chlorpromazine or thioridazine results in precipitate formation, and, in the case of chlorpromazine, there has been a report of a patient passing an orange rubbery precipitate in the stool following coadministration of the two drugs (see PRECAUTIONS, Drug Interactions). Because the extent to which this occurs with other liquid medications is not known, Tegretol suspension should not be administered simultaneously with other liquid medications or diluents.
Monitoring of blood levels has increased the efficacy and safety of anticonvulsants (see PRECAUTIONS, Laboratory Tests). Dosage should be adjusted to the needs of the individual patient. A low initial daily dosage with a gradual increase is advised. As soon as adequate control is achieved, the dosage may be reduced very gradually to the minimum effective level. Medication should be taken with meals.
Since a given dose of Tegretol suspension will produce higher peak levels than the same dose given as the tablet, it is recommended to start with low doses (children 6 to 12 years: ½ teaspoon q.i.d.) and to increase slowly to avoid unwanted side effects.
Conversion of patients from oral Tegretol tablets to Tegretol suspension: Patients should be converted by administering the same number of mg per day in smaller, more frequent doses (i.e., b.i.d. tablets to t.i.d. suspension).
Tegretol-XR is an extended-release formulation for twice-a-day administration. When converting patients from Tegretol conventional tablets to Tegretol-XR, the same total daily mg dose of Tegretol-XR should be administered. Tegretol-XR tablets must be swallowed whole and never crushed or chewed. Tegretol-XR tablets should be inspected for chips or cracks. Damaged tablets, or tablets without a release portal, should not be consumed. Tegretol-XR tablet coating is not absorbed and is excreted in the feces; these coatings may be noticeable in the stool.
Epilepsy
Adults and children over 12 years of age-Initial: Either 200 mg b.i.d. for tablets and XR tablets, or 1 teaspoon q.i.d. for suspension (400 mg/day). Increase at weekly intervals by adding up to 200 mg/day using a b.i.d. regimen of Tegretol-XR or a t.i.d. or q.i.d. regimen of the other formulations until the optimal response is obtained. Dosage generally should not exceed 1000 mg daily in children 12 to 15 years of age, and 1200 mg daily in patients above 15 years of age. Doses up to 1600 mg daily have been used in adults in rare instances. Maintenance: Adjust dosage to the minimum effective level, usually 800 to 1200 mg daily.
Children 6 to 12 years of age-Initial: Either 100 mg b.i.d. for tablets or XR tablets, or ½ teaspoon q.i.d. for suspension (200 mg/day). Increase at weekly intervals by adding up to 100 mg/day using a b.i.d. regimen of Tegretol-XR or a t.i.d. or q.i.d. regimen of the other formulations until the optimal response is obtained. Dosage generally should not exceed 1000 mg daily. Maintenance: Adjust dosage to the minimum effective level, usually 400 to 800 mg daily.
Children under 6 years of age-Initial: 10 to 20 mg/kg/day b.i.d. or t.i.d. as tablets, or q.i.d. as suspension. Increase weekly to achieve optimal clinical response administered t.i.d. or q.i.d. Maintenance: Ordinarily, optimal clinical response is achieved at daily doses below 35 mg/kg. If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the therapeutic range. No recommendation regarding the safety of carbamazepine for use at doses above 35 mg/kg/24 hours can be made.
Combination Therapy: Tegretol may be used alone or with other anticonvulsants. When added to existing anticonvulsant therapy, the drug should be added gradually while the other anticonvulsants are maintained or gradually decreased, except phenytoin, which may have to be increased (see PRECAUTIONS, Drug Interactions, and Pregnancy Category D).
Trigeminal Neuralgia
Initial: On the first day, either 100 mg b.i.d. for tablets or XR tablets, or ½ teaspoon q.i.d. for suspension, for a total daily dose of 200 mg. This daily dose may be increased by up to 200 mg/day using increments of 100 mg every 12 hours for tablets or XR tablets, or 50 mg (½ teaspoon) q.i.d. for suspension, only as needed to achieve freedom from pain. Do not exceed 1200 mg daily. Maintenance: Control of pain can be maintained in most patients with 400 to 800 mg daily. However, some patients may be maintained on as little as 200 mg daily, while others may require as much as 1200 mg daily. At least once every 3 months throughout the treatment period, attempts should be made to reduce the dose to the minimum effective level or even to discontinue the drug.
Monitoring
Hypersensitivity reactions to carbamazepine have been reported in patients who previously experienced this reaction to anticonvulsants including phenytoin, primidone, and phenobarbital. If such history is present, benefits and risks should be carefully considered and, if carbamazepine is initiated, the signs and symptoms of hypersensitivity should be carefully monitored.
Antiepileptic drugs (AEDs), including Tegretol, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Complete pretreatment blood counts, including platelets and possibly reticulocytes and serum iron, should be obtained as a baseline. If a patient in the course of treatment exhibits low or decreased white blood cell or platelet counts, the patient should be monitored closely. Discontinuation of the drug should be considered if any evidence of significant bone marrow depression develops.
Monitoring of blood levels (see CLINICAL PHARMACOLOGY) has increased the efficacy and safety of anticonvulsants. This monitoring may be particularly useful in cases of dramatic increase in seizure frequency and for verification of compliance. In addition, measurement of drug serum levels may aid in determining the cause of toxicity when more than one medication is being used.
When carbamazepine is given with drugs that can increase or decrease carbamazepine levels, close monitoring of carbamazepine levels is indicated and dosage adjustment may be required.
When used concomitantly with Tegretol, monitoring of concentrations or dosage adjustment of these agents may be necessary:
When carbamazepine is added to aripiprazole, the aripiprazole dose should be doubled. Additional dose increases should be based on clinical evaluation. If carbamazepine is later withdrawn, the aripiprazole dose should be reduced.
When carbamazepine is used with tacrolimus, monitoring of tacrolimus blood concentrations and appropriate dosage adjustments are recommended.
The use of concomitant strong CYP3A4 inducers such as carbamazepine should be avoided with temsirolimus. If patients must be coadministered carbamazepine with temsirolimus, an adjustment of temsirolimus dosage should be considered.
The use of carbamazepine with lapatinib should generally be avoided. If carbamazepine is started in a patient already taking lapatinib, the dose of lapatinib should be gradually titrated up. If carbamazepine is discontinued, the lapatinib dose should be reduced.
Concomitant use of carbamazepine with nefazodone results in plasma concentrations of nefazodone and its active metabolite insufficient to achieve a therapeutic effect. Coadministration of carbamazepine with nefazodone is contraindicated (see CONTRAINDICATIONS).
Monitor concentrations of valproate when Tegretol is introduced or withdrawn in patients using valproic acid.
In addition, Tegretol causes, or would be expected to cause, decreased levels of the following drugs, for which monitoring of concentrations or dosage adjustment may be necessary: acetaminophen, albendazole, alprazolam, aprepitant, buprenorphone, bupropion, citalopram, clonazepam, clozapine, corticosteroids (e.g., prednisolone, dexamethasone), cyclosporine, dicumarol, dihydropyridine calcium channel blockers (e.g., felodipine), doxycycline, ethosuximide, everolimus, haloperidol, imatinib, itraconazole, lamotrigine, levothyroxine, methadone, methsuximide, mianserin, midazolam, olanzapine, oral and other hormonal contraceptives, oxcarbazepine, paliperidone, phensuximide, phenytoin, praziquantel, protease inhibitors, risperidone, sertraline, sirolimus, tadalafil, theophylline, tiagabine, topiramate, tramadol, trazodone, tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline), valproate, warfarin, ziprasidone, zonisamide.
Resistance to the neuromuscular blocking action of the nondepolarizing neuromuscular blocking agents pancuronium, vecuronium, rocuronium and cisatracurium has occurred in patients chronically administered carbamazepine. Whether or not carbamazepine has the same effect on other non-depolarizing agents is unknown. Patients should be monitored closely for more rapid recovery from neuromuscular blockade than expected, and infusion rate requirements may be higher.
IV Compatibility
There is limited information regarding IV Compatibility of Carbamazepine in the drug label.
Overdosage
Acute Toxicity
Lowest known lethal dose: adults, 3.2 g (a 24-year-old woman died of a cardiac arrest and a 24-year-old man died of pneumonia and hypoxic encephalopathy); children, 4 g (a 14-year-old girl died of a cardiac arrest), 1.6 g (a 3-year-old girl died of aspiration pneumonia).
Oral LD50 in animals (mg/kg): mice, 1100 to 3750; rats, 3850 to 4025; rabbits, 1500 to 2680; guinea pigs, 920.
Signs and Symptoms
The first signs and symptoms appear after 1 to 3 hours. Neuromuscular disturbances are the most prominent. Cardiovascular disorders are generally milder, and severe cardiac complications occur only when very high doses (greater than 60 g) have been ingested.
Cardiovascular System: Tachycardia, hypotension or hypertension, shock, conduction disorders.
Nervous System and Muscles: Impairment of consciousness ranging in severity to deep coma. Convulsions, especially in small children. Motor restlessness, muscular twitching, tremor, athetoid movements, opisthotonos, ataxia, drowsiness, dizziness, mydriasis, nystagmus, adiadochokinesia, ballism, psychomotor disturbances, dysmetria. Initial hyperreflexia, followed by hyporeflexia.
Gastrointestinal Tract: Nausea, vomiting.
Kidneys and Bladder: Anuria or oliguria, urinary retention.
Laboratory Findings: Isolated instances of overdosage have included leukocytosis, reduced leukocyte count, glycosuria, and acetonuria. EEG may show dysrhythmias.
Combined Poisoning: When alcohol, tricyclic antidepressants, barbiturates, or hydantoins are taken at the same time, the signs and symptoms of acute poisoning with Tegretol may be aggravated or modified.
Treatment
The prognosis in cases of severe poisoning is critically dependent upon prompt elimination of the drug, which may be achieved by inducing vomiting, irrigating the stomach, and by taking appropriate steps to diminish absorption. If these measures cannot be implemented without risk on the spot, the patient should be transferred at once to a hospital, while ensuring that vital functions are safeguarded. There is no specific antidote.
Elimination of the Drug: Induction of vomiting.
Gastric lavage. Even when more than 4 hours have elapsed following ingestion of the drug, the stomach should be repeatedly irrigated, especially if the patient has also consumed alcohol.
Measures to Reduce Absorption: Activated charcoal, laxatives.
Measures to Accelerate Elimination: Forced diuresis.
Dialysis is indicated only in severe poisoning associated with renal failure. Replacement transfusion is indicated in severe poisoning in small children.
Respiratory Depression: Keep the airways free; resort, if necessary, to endotracheal intubation, artificial respiration, and administration of oxygen.
Hypotension, Shock: Keep the patient’s legs raised and administer a plasma expander. If blood pressure fails to rise despite measures taken to increase plasma volume, use of vasoactive substances should be considered.
Convulsions: Diazepam or barbiturates.
Warning: Diazepam or barbiturates may aggravate respiratory depression (especially in children), hypotension, and coma. However, barbiturates should not be used if drugs that inhibit monoamine oxidase have also been taken by the patient either in overdosage or in recent therapy (within 1 week).
Surveillance: Respiration, cardiac function (ECG monitoring), blood pressure, body temperature, pupillary reflexes, and kidney and bladder function should be monitored for several days.
Treatment of Blood Count Abnormalities: If evidence of significant bone marrow depression develops, the following recommendations are suggested: (1) stop the drug, (2) perform daily CBC, platelet, and reticulocyte counts, (3) do a bone marrow aspiration and trephine biopsy immediately and repeat with sufficient frequency to monitor recovery.
Special periodic studies might be helpful as follows: (1) white cell and platelet antibodies, (2) 59Fe-ferrokinetic studies, (3) peripheral blood cell typing, (4) cytogenetic studies on marrow and peripheral blood, (5) bone marrow culture studies for colony-forming units, (6) hemoglobin electrophoresis for A2 and F hemoglobin, and (7) serum folic acid and B12 levels.
A fully developed aplastic anemia will require appropriate, intensive monitoring and therapy, for which specialized consultation should be sought.
Pharmacology
There is limited information regarding Carbamazepine Pharmacology in the drug label.
Mechanism of Action
Tegretol has demonstrated anticonvulsant properties in rats and mice with electrically and chemically induced seizures. It appears to act by reducing polysynaptic responses and blocking the post-tetanic potentiation. Tegretol greatly reduces or abolishes pain induced by stimulation of the infraorbital nerve in cats and rats. It depresses thalamic potential and bulbar and polysynaptic reflexes, including the linguomandibular reflex in cats. Tegretol is chemically unrelated to other anticonvulsants or other drugs used to control the pain of trigeminal neuralgia. The mechanism of action remains unknown.
The principal metabolite of Tegretol, carbamazepine-10,11-epoxide, has anticonvulsant activity as demonstrated in several in vivo animal models of seizures. Though clinical activity for the epoxide has been postulated, the significance of its activity with respect to the safety and efficacy of Tegretol has not been established.
Tegretol, carbamazepine USP, is an anticonvulsant and specific analgesic for trigeminal neuralgia, available for oral administration as chewable tablets of 100 mg, tablets of 200 mg, XR tablets of 100, 200, and 400 mg, and as a suspension of 100 mg/5 mL (teaspoon). Its chemical name is 5H-dibenz[b,f ]azepine-5-carboxamide, and its structural formula is:
Carbamazepine USP is a white to off-white powder, practically insoluble in water and soluble in alcohol and in acetone. Its molecular weight is 236.27.
There is limited information regarding Pharmacodynamics of Carbamazepine in the drug label.
Pharmacokinetics
In clinical studies, Tegretol suspension, conventional tablets, and XR tablets delivered equivalent amounts of drug to the systemic circulation. However, the suspension was absorbed somewhat faster, and the XR tablet slightly slower, than the conventional tablet. The bioavailability of the XR tablet was 89% compared to suspension. Following a b.i.d. dosage regimen, the suspension provides higher peak levels and lower trough levels than those obtained from the conventional tablet for the same dosage regimen. On the other hand, following a t.i.d. dosage regimen, Tegretol suspension affords steady-state plasma levels comparable to Tegretol tablets given b.i.d. when administered at the same total mg daily dose. Following a b.i.d. dosage regimen, Tegretol-XR tablets afford steady-state plasma levels comparable to conventional Tegretol tablets given q.i.d., when administered at the same total mg daily dose. Tegretol in blood is 76% bound to plasma proteins. Plasma levels of Tegretol are variable and may range from 0.5 to 25 mcg/mL, with no apparent relationship to the daily intake of the drug. Usual adult therapeutic levels are between 4 and 12 mcg/mL. In polytherapy, the concentration of Tegretol and concomitant drugs may be increased or decreased during therapy, and drug effects may be altered (see PRECAUTIONS, Drug Interactions). Following chronic oral administration of suspension, plasma levels peak at approximately 1.5 hours compared to 4 to 5 hours after administration of conventional Tegretol tablets, and 3 to 12 hours after administration of Tegretol-XR tablets. The CSF/serum ratio is 0.22, similar to the 24% unbound Tegretol in serum. Because Tegretol induces its own metabolism, the half-life is also variable.
Autoinduction is completed after 3 to 5 weeks of a fixed dosing regimen. Initial half-life values range from 25 to 65 hours, decreasing to 12 to 17 hours on repeated doses. Tegretol is metabolized in the liver. Cytochrome P450 3A4 was identified as the major isoform responsible for the formation of carbamazepine-10,11-epoxide from Tegretol. Human microsomal epoxide hydrolase has been identified as the enzyme responsible for the formation of the 10,11-transdiol derivative from carbamazepine-10,11 epoxide. After oral administration of 14C-carbamazepine, 72% of the administered radioactivity was found in the urine and 28% in the feces. This urinary radioactivity was composed largely of hydroxylated and conjugated metabolites, with only 3% of unchanged Tegretol.
The pharmacokinetic parameters of Tegretol disposition are similar in children and in adults. However, there is a poor correlation between plasma concentrations of carbamazepine and Tegretol dose in children. Carbamazepine is more rapidly metabolized to carbamazepine-10,11-epoxide (a metabolite shown to be equipotent to carbamazepine as an anticonvulsant in animal screens) in the younger age groups than in adults. In children below the age of 15, there is an inverse relationship between CBZ-E/CBZ ratio and increasing age (in one report from 0.44 in children below the age of 1 year to 0.18 in children between 10 to 15 years of age).
The effects of race and gender on carbamazepine pharmacokinetics have not been systematically evaluated.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carbamazepine, when administered to Sprague-Dawley rats for two years in the diet at doses of 25, 75, and 250 mg/kg/day, resulted in a dose-related increase in the incidence of hepatocellular tumors in females and of benign interstitial cell adenomas in the testes of males.
Carbamazepine must, therefore, be considered to be carcinogenic in Sprague-Dawley rats. Bacterial and mammalian mutagenicity studies using carbamazepine produced negative results. The significance of these findings relative to the use of carbamazepine in humans is, at present, unknown.
Clinical Studies
There is limited information regarding Clinical Studies of Carbamazepine in the drug label.
How Supplied
Chewable Tablets 100 mg - round, red-speckled, pink, single-scored (imprinted Tegretol on one side and 52 twice on the scored side)
Bottles of 100………………………………………………………………………………….NDC 0078-0492-05
Unit Dose (blister pack)
Box of 100 (strips of 10)……………………………………………………………………....NDC 0078-0492-35
Do not store above 30°C (86°F). Protect from light and moisture.
Dispense in tight, light-resistant container (USP).
Meets USP Dissolution Test 1.
Tablets 200 mg - capsule-shaped, pink, single-scored (imprinted Tegretol on one side and 27 twice on the partially scored side)
Bottles of 100.............................................................................................................................NDC 0078-0509-05
Do not store above 30°C (86°F). Protect from moisture.
Dispense in tight container (USP).
Meets USP Dissolution Test 2.
XR Tablets 100 mg - round, yellow, coated (imprinted T on one side and 100 mg on the other), release portal on one side
Bottles of 100.............................................................................................................................NDC 0078-0510-05
XR Tablets 200 mg - round, pink, coated (imprinted T on one side and 200 mg on the other), release portal on one side
Bottles of 100.............................................................................................................................NDC 0078-0511-05
XR Tablets 400 mg - round, brown, coated (imprinted T on one side and 400 mg on the other), release portal on one side
Bottles of 100.............................................................................................................................NDC 0078-0512-05
Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) Protect from moisture.
Dispense in tight container (USP).
Suspension 100 mg/5 mL (teaspoon) – yellow-orange, citrus-vanilla flavored
Bottles of 450 mL.......................................................................................................................................NDC 0078-0508-83
Shake well before using.
Do not store above 30°C (86°F). Dispense in tight, light-resistant container (USP).
Storage
Chewable Tablets 100 mg - round, red-speckled, pink, single-scored (imprinted Tegretol on one side and 52 twice on the scored side):
Do not store above 30°C (86°F). Protect from light and moisture.
Dispense in tight, light-resistant container (USP).
Meets USP Dissolution Test 1.
Tablets 200 mg - capsule-shaped, pink, single-scored (imprinted Tegretol on one side and 27 twice on the partially scored side): Do not store above 30°C (86°F). Protect from moisture.
Dispense in tight container (USP).
Meets USP Dissolution Test 2.
XR Tablets 400 mg - round, brown, coated (imprinted T on one side and 400 mg on the other), release portal on one side: Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) Protect from moisture.
Dispense in tight container (USP).
Suspension 100 mg/5 mL (teaspoon) – yellow-orange, citrus-vanilla flavored: Do not store above 30°C (86°F). Dispense in tight, light-resistant container (USP).
Thorazine® is a registered trademark of GlaxoSmithKline.
Images
Drug Images
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Patients should be informed of the availability of a Medication Guide and they should be instructed to read the Medication Guide before taking Tegretol.
Patients should be made aware of the early toxic signs and symptoms of a potential hematologic problem, as well as dermatologic, hypersensitivity or hepatic reactions. These symptoms may include, but are not limited to, fever, sore throat, rash, ulcers in the mouth, easy bruising, lymphadenopathy and petechial or purpuric hemorrhage, and in the case of liver reactions, anorexia, nausea/vomiting, or jaundice. The patient should be advised that, because these signs and symptoms may signal a serious reaction, that they must report any occurrence immediately to a physician. In addition, the patient should be advised that these signs and symptoms should be reported even if mild or when occurring after extended use.
Patients should be advised that serious skin reactions have been reported in association with Tegretol. In the event a skin reaction should occur while taking Tegretol, patients should consult with their physician immediately (see WARNINGS).
Patients, their caregivers, and families should be counseled that AEDs, including Tegretol, may increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of symptoms of depression, any unusual changes in mood or behavior, or the emergence of suicidal thoughts, behavior, or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
Tegretol may interact with some drugs. Therefore, patients should be advised to report to their doctors the use of any other prescription or nonprescription medications or herbal products.
Caution should be exercised if alcohol is taken in combination with Tegretol therapy, due to a possible additive sedative effect.
Since dizziness and drowsiness may occur, patients should be cautioned about the hazards of operating machinery or automobiles or engaging in other potentially dangerous tasks.
Patients should be encouraged to enroll in the NAAED Pregnancy Registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll free number 1-888-233-2334 (see WARNINGS, Usage in Pregnancy subsection).
Precautions with Alcohol
Caution should be exercised if alcohol is taken in combination with Tegretol therapy, due to a possible additive sedative effect.
Combined Poisoning: When alcohol, tricyclic antidepressants, barbiturates, or hydantoins are taken at the same time, the signs and symptoms of acute poisoning with Tegretol may be aggravated or modified.
