Levothyroxine (injection): Difference between revisions
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|clinicalTrials=* Excessive doses of levothyroxine can predispose to signs and symptoms compatible with [[hyperthyroidism]]. The signs and symptoms of [[thyrotoxicosis]] include, but are not limited to: [[goitre|exophthalmic goiter]], weight loss, increased appetite, [[palpitations]], [[nervousness]], [[diarrhea]], [[abdominal cramps]], [[sweating]], [[tachycardia]], increased pulse and blood pressure, [[cardiac arrhythmias]], [[angina pectoris]], [[tremors]], [[insomnia]], [[heat intolerance]], [[fever]], and menstrual irregularities. | |clinicalTrials=* Excessive doses of levothyroxine can predispose to signs and symptoms compatible with [[hyperthyroidism]]. The signs and symptoms of [[thyrotoxicosis]] include, but are not limited to: [[goitre|exophthalmic goiter]], weight loss, increased appetite, [[palpitations]], [[nervousness]], [[diarrhea]], [[abdominal cramps]], [[sweating]], [[tachycardia]], increased pulse and blood pressure, [[cardiac arrhythmias]], [[angina pectoris]], [[tremors]], [[insomnia]], [[heat intolerance]], [[fever]], and menstrual irregularities. | ||
|postmarketing=There is limited information regarding <i>Postmarketing Experience</i> of {{PAGENAME}} in the drug label. | |postmarketing=There is limited information regarding <i>Postmarketing Experience</i> of {{PAGENAME}} in the drug label. | ||
|drugInteractions=* Many drugs affect thyroid hormone pharmacokinetics and metabolism (e.g., synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to Levothyroxine Sodium for Injection. In addition, thyroid hormones and thyroid status have varied effects on the pharmacokinetics and actions of other drugs. | |||
'''Antidiabetic Therapy''' | |||
* Addition of levothyroxine to antidiabetic or insulin therapy may result in increased antidiabetic agent or insulin requirements. Careful monitoring of diabetic control is recommended, especially when thyroid therapy is started, changed, or discontinued. | |||
'''Oral Anticoagulants''' | |||
* Levothyroxine increases the response to oral anticoagulant therapy. Therefore, a decrease in the dose of anticoagulant may be warranted with correction of the hypothyroid state or when the Levothyroxine Sodium for Injection dose is increased. Prothrombin time should be closely monitored to permit appropriate and timely dosage adjustments. | |||
'''Digitalis Glycosides''' | |||
* The therapeutic effects of digitalis glycosides may be reduced by levothyroxine. Serum digitalis glycoside levels may be decreased when a hypothyroid patient becomes euthyroid, necessitating an increase in the dose of digitalis glycosides. | |||
'''Antidepressant Therapy''' | |||
* Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines. Toxic effects may include increased risk of cardiac arrhythmias and CNS stimulation; onset of action of tricyclics may be accelerated. Administration of sertraline in patients stabilized on levothyroxine may result in increased levothyroxine requirements. | |||
'''Ketamine''' | |||
* Concurrent use may produce marked hypertension and tachycardia; cautious administration to patients receiving thyroid hormone therapy is recommended. | |||
'''Sympathomimetics''' | |||
* Concurrent use may increase the effects of sympathomimetics or thyroid hormone. Thyroid hormones may increase the risk of coronary insufficiency when sympathomimetic agents are administered to patients with coronary artery disease. | |||
'''Drug-Laboratory Test Interactions''' | |||
* Changes in thyroxine binding globulin (TBG) concentration must be considered when interpreting levothyroxine and triiodothyronine values, which necessitates measurement and evaluation of unbound (free) hormone and/or determination of the free levothyroxine index. Pregnancy, infectious hepatitis, estrogens, estrogen containing oral contraceptives, and acute intermittent porphyria increase TBG concentrations. Decreases in TBG concentrations are observed in nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, and after androgen or corticosteroid therapy. Familial hyper or hypo thyroxine binding globulinemias have been described, with the incidence of TBG deficiency approximating 1 in 9000. | |||
|useInPregnancyFDA=* '''Pregnancy Category''' | |useInPregnancyFDA=* '''Pregnancy Category''' | ||
|useInPregnancyAUS=* '''Australian Drug Evaluation Committee (ADEC) Pregnancy Category''' | |useInPregnancyAUS=* '''Australian Drug Evaluation Committee (ADEC) Pregnancy Category''' |
Revision as of 18:11, 17 May 2015
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2]
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Black Box Warning
WARNING:
See full prescribing information for complete Boxed Warning.
* NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including Levothyroxine Sodium for Injection , should not be used for the treatment of obesity or for weight loss.
|
Overview
Levothyroxine (injection) is a {{{drugClass}}} that is FDA approved for the treatment of myxedema coma. There is a Black Box Warning for this drug as shown here. Common adverse reactions include weight loss, increased appetite, palpitations, nervousness, diarrhea, abdominal cramps, sweating, tachycardia, insomnia and fever.
Adult Indications and Dosage
FDA-Labeled Indications and Dosage (Adult)
Indications
- Levothyroxine Sodium for Injection is indicated for the treatment of myxedema coma. Important Limitations of Use: The relative bioavailability between Levothyroxine Sodium for Injection and oral levothyroxine products has not been established. Caution should be used when switching patients from oral levothyroxine products to Levothyroxine Sodium for Injection as accurate dosing conversion has not been studied.
Dosage
- An initial intravenous loading dose of Levothyroxine Sodium for Injection between 300 to 500 mcg, followed by once daily intravenous maintenance doses between 50 and 100 mcg, should be administered, as clinically indicated, until the patient can tolerate oral therapy. The age, general physical condition, cardiac risk factors, and clinical severity of myxedema and duration of myxedema symptoms should be considered when determining the starting and maintenance dosages of Levothyroxine Sodium for Injection.
- Levothyroxine Sodium for Injection produces a gradual increase in the circulating concentrations of the hormone with an approximate half-life of 9 to 10 days in hypothyroid patients. Daily administration of Levothyroxine Sodium for Injection should be maintained until the patient is capable of tolerating an oral dose and is clinically stable. For chronic treatment of hypothyroidism, an oral dosage form of levothyroxine should be used to maintain a euthyroid state. Relative bioavailability between Levothyroxine Sodium for Injection and oral levothyroxine products has not been established. Based on medical practice, the relative bioavailability between oral and intravenous administration of Levothyroxine Sodium for Injection is estimated to be from 48 to 74%. Due to differences in absorption characteristics of patients and the oral levothyroxine product formulations, TSH and thyroid hormone levels should be measured a few weeks after initiating oral levothyroxine and dose adjusted accordingly.
Dosing in the Elderly and in Patients with Cardiovascular Disease
- Intravenous levothyroxine may be associated with cardiac toxicity—including arrhythmias, tachycardia, myocardial ischemia and infarction, or worsening of congestive heart failure and death—in the elderly and in those with underlying cardiovascular disease. Therefore, cautious use, including doses in the lower end of the recommended range, may be warranted in these populations.
Reconstitution Directions
- Reconstitute the lyophilized Levothyroxine Sodium for Injection by aseptically adding 5 mL of 0.9% Sodium Chloride Injection, USP only. Shake vial to ensure complete mixing. The resultant solution will have a final concentration of approximately 20 mcg per mL, 40 mcg per mL and and 100 mcg per mL for the 100 mcg, 200 mcg and 500 mcg vials, respectively. Reconstituted drug product is preservative free and is stable for 4 hours. Discard any unused portion. DO NOT ADD LEVOTHYROXINE SODIUM FOR INJECTION TO OTHER IV FLUIDS. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
DOSAGE FORMS AND STRENGTHS
- Levothyroxine Sodium for Injection is supplied as a lyophilized powder at three strengths in single use amber-colored vials: 100 mcg, 200 mcg and 500 mcg.
Off-Label Use and Dosage (Adult)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Levothyroxine (injection) in adult patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Levothyroxine (injection) in adult patients.
Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Levothyroxine (injection) in pediatric patients.
Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Levothyroxine (injection) in pediatric patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Levothyroxine (injection) in pediatric patients.
Contraindications
- None
Warnings
WARNING:
See full prescribing information for complete Boxed Warning.
* NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS Thyroid hormones, including Levothyroxine Sodium for Injection , should not be used for the treatment of obesity or for weight loss.
|
Risk of Cardiac Complications in Elderly and in Patients with Cardiovascular Disease
- Excessive bolus dosing of Levothyroxine Sodium for Injection (greater than 500 mcg) are associated with cardiac complications, particularly in the elderly and in patients with an underlying cardiac condition. Adverse events that can potentially be related to the administration of large doses of Levothyroxine Sodium for Injection include arrhythmias, tachycardia, myocardial ischemia and infarction, or worsening of congestive heart failure and death. Cautious use, including doses in the lower end of the recommended range, may be warranted in these populations. Close observation of the patient following the administration of Levothyroxine Sodium for Injection is advised.
Need for Concomitant Glucocorticoids and Monitoring for Other Diseases in Patients with Endocrine Disorders
- Occasionally, chronic autoimmune thyroiditis, which can lead to myxedema coma, may occur in association with other autoimmune disorders such as adrenal insufficiency, pernicious anemia, and insulin‑dependent diabetes mellitus. Patients should be treated with replacement glucocorticoids prior to initiation of treatment with Levothyroxine Sodium for Injection, until adrenal function has been adequately assessed. Failure to do so may precipitate an acute adrenal crisis when thyroid hormone therapy is initiated, due to increased metabolic clearance of glucocorticoids by thyroid hormone. With initiation of Levothyroxine Sodium for Injection, patients with myxedema coma should also be monitored for previously undiagnosed diabetes insipidus.
Not Indicated for Treatment of Obesity
- Thyroid hormones, including Levothyroxine Sodium for Injection, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects
Adverse Reactions
Clinical Trials Experience
- Excessive doses of levothyroxine can predispose to signs and symptoms compatible with hyperthyroidism. The signs and symptoms of thyrotoxicosis include, but are not limited to: exophthalmic goiter, weight loss, increased appetite, palpitations, nervousness, diarrhea, abdominal cramps, sweating, tachycardia, increased pulse and blood pressure, cardiac arrhythmias, angina pectoris, tremors, insomnia, heat intolerance, fever, and menstrual irregularities.
Postmarketing Experience
There is limited information regarding Postmarketing Experience of Levothyroxine (injection) in the drug label.
Drug Interactions
- Many drugs affect thyroid hormone pharmacokinetics and metabolism (e.g., synthesis, secretion, catabolism, protein binding, and target tissue response) and may alter the therapeutic response to Levothyroxine Sodium for Injection. In addition, thyroid hormones and thyroid status have varied effects on the pharmacokinetics and actions of other drugs.
Antidiabetic Therapy
- Addition of levothyroxine to antidiabetic or insulin therapy may result in increased antidiabetic agent or insulin requirements. Careful monitoring of diabetic control is recommended, especially when thyroid therapy is started, changed, or discontinued.
Oral Anticoagulants
- Levothyroxine increases the response to oral anticoagulant therapy. Therefore, a decrease in the dose of anticoagulant may be warranted with correction of the hypothyroid state or when the Levothyroxine Sodium for Injection dose is increased. Prothrombin time should be closely monitored to permit appropriate and timely dosage adjustments.
Digitalis Glycosides
- The therapeutic effects of digitalis glycosides may be reduced by levothyroxine. Serum digitalis glycoside levels may be decreased when a hypothyroid patient becomes euthyroid, necessitating an increase in the dose of digitalis glycosides.
Antidepressant Therapy
- Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and levothyroxine may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines. Toxic effects may include increased risk of cardiac arrhythmias and CNS stimulation; onset of action of tricyclics may be accelerated. Administration of sertraline in patients stabilized on levothyroxine may result in increased levothyroxine requirements.
Ketamine
- Concurrent use may produce marked hypertension and tachycardia; cautious administration to patients receiving thyroid hormone therapy is recommended.
Sympathomimetics
- Concurrent use may increase the effects of sympathomimetics or thyroid hormone. Thyroid hormones may increase the risk of coronary insufficiency when sympathomimetic agents are administered to patients with coronary artery disease.
Drug-Laboratory Test Interactions
- Changes in thyroxine binding globulin (TBG) concentration must be considered when interpreting levothyroxine and triiodothyronine values, which necessitates measurement and evaluation of unbound (free) hormone and/or determination of the free levothyroxine index. Pregnancy, infectious hepatitis, estrogens, estrogen containing oral contraceptives, and acute intermittent porphyria increase TBG concentrations. Decreases in TBG concentrations are observed in nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, and after androgen or corticosteroid therapy. Familial hyper or hypo thyroxine binding globulinemias have been described, with the incidence of TBG deficiency approximating 1 in 9000.
Use in Specific Populations
Pregnancy
- Pregnancy Category
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Levothyroxine (injection) in women who are pregnant.
Labor and Delivery
There is no FDA guidance on use of Levothyroxine (injection) during labor and delivery.
Nursing Mothers
There is no FDA guidance on the use of Levothyroxine (injection) with respect to nursing mothers.
Pediatric Use
There is no FDA guidance on the use of Levothyroxine (injection) with respect to pediatric patients.
Geriatic Use
There is no FDA guidance on the use of Levothyroxine (injection) with respect to geriatric patients.
Gender
There is no FDA guidance on the use of Levothyroxine (injection) with respect to specific gender populations.
Race
There is no FDA guidance on the use of Levothyroxine (injection) with respect to specific racial populations.
Renal Impairment
There is no FDA guidance on the use of Levothyroxine (injection) in patients with renal impairment.
Hepatic Impairment
There is no FDA guidance on the use of Levothyroxine (injection) in patients with hepatic impairment.
Females of Reproductive Potential and Males
There is no FDA guidance on the use of Levothyroxine (injection) in women of reproductive potentials and males.
Immunocompromised Patients
There is no FDA guidance one the use of Levothyroxine (injection) in patients who are immunocompromised.
Administration and Monitoring
Administration
- Oral
- Intravenous
Monitoring
There is limited information regarding Monitoring of Levothyroxine (injection) in the drug label.
- Description
IV Compatibility
There is limited information regarding IV Compatibility of Levothyroxine (injection) in the drug label.
Overdosage
Acute Overdose
Signs and Symptoms
- Description
Management
- Description
Chronic Overdose
There is limited information regarding Chronic Overdose of Levothyroxine (injection) in the drug label.
Pharmacology
There is limited information regarding Levothyroxine (injection) Pharmacology in the drug label.
Mechanism of Action
Structure
Pharmacodynamics
There is limited information regarding Pharmacodynamics of Levothyroxine (injection) in the drug label.
Pharmacokinetics
There is limited information regarding Pharmacokinetics of Levothyroxine (injection) in the drug label.
Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Levothyroxine (injection) in the drug label.
Clinical Studies
There is limited information regarding Clinical Studies of Levothyroxine (injection) in the drug label.
How Supplied
Storage
There is limited information regarding Levothyroxine (injection) Storage in the drug label.
Images
Drug Images
{{#ask: Page Name::Levothyroxine (injection) |?Pill Name |?Drug Name |?Pill Ingred |?Pill Imprint |?Pill Dosage |?Pill Color |?Pill Shape |?Pill Size (mm) |?Pill Scoring |?NDC |?Drug Author |format=template |template=DrugPageImages |mainlabel=- |sort=Pill Name }}
Package and Label Display Panel
{{#ask: Label Page::Levothyroxine (injection) |?Label Name |format=template |template=DrugLabelImages |mainlabel=- |sort=Label Page }}
Patient Counseling Information
There is limited information regarding Patient Counseling Information of Levothyroxine (injection) in the drug label.
Precautions with Alcohol
- Alcohol-Levothyroxine (injection) interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
Brand Names
- LEVOTHYROXINE SODIUM®[1]
Look-Alike Drug Names
There is limited information regarding Levothyroxine (injection) Look-Alike Drug Names in the drug label.
Drug Shortage Status
Price
References
The contents of this FDA label are provided by the National Library of Medicine.