'''Note''': β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
'''Note''': β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
'''Pharyngitis and Tonsillitis''', caused by Streptococcus pyogenes
* '''Pharyngitis and Tonsillitis''', caused by Streptococcus pyogenes
'''Note''': Penicillin is the usual drug of choice in the treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cefaclor is generally effective in the eradication of streptococci from the nasopharynx; however, substantial data establishing the efficacy of cefaclor in the subsequent prevention of rheumatic fever are not available at present.
'''Note''': Penicillin is the usual drug of choice in the treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cefaclor is generally effective in the eradication of streptococci from the nasopharynx; however, substantial data establishing the efficacy of cefaclor in the subsequent prevention of rheumatic fever are not available at present.
Line 34:
Line 34:
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefaclor and other antibacterial drugs, cefaclor should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefaclor and other antibacterial drugs, cefaclor should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
|offLabelAdultGuideSupport======Condition1=====
* Developed by:
==Dosage==
* The usual adult dosage is 250 mg every 8 hours. For more severe infections (such as [[pneumonia]]) or those caused by less susceptible organisms, doses may be doubled.
* Cefaclor may be administered in the presence of impaired renal function. Under such a condition, the dosage usually is unchanged.
* In the treatment of β-hemolytic streptococcal infections, a therapeutic dosage of cefaclor should be administered for at least 10 days.
|offLabelAdultGuideSupport=There is limited information regarding <i>Off-Label Guideline-Supported Use</i> of {{PAGENAME}} in adult patients.
|offLabelAdultNoGuideSupport=There is limited information regarding <i>Off-Label Non–Guideline-Supported Use</i> of {{PAGENAME}} in adult patients.
|fdaLIADPed===Indications==
Cefaclor is indicated in the treatment of the following infections when caused by susceptible strains of the designated microorganisms:
* '''Otitis media''' caused by Streptococcus pneumoniae, Haemophilus influenzae, staphylococci, and Streptococcus pyogenes
* Class of Recommendation:
'''Note''': β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
* Strength of Evidence:
* '''Lower respiratory tract infections''', including [[pneumonia]] caused by [[Streptococcus pneumoniae]], [[Haemophilus influenzae]], and [[Streptococcus pyogenes]].
* Dosing Information
'''Note''': β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
:* Dosage
* '''Pharyngitis and Tonsillitis''', caused by Streptococcus pyogenes
=====Condition2=====
'''Note''': Penicillin is the usual drug of choice in the treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cefaclor is generally effective in the eradication of streptococci from the nasopharynx; however, substantial data establishing the efficacy of cefaclor in the subsequent prevention of rheumatic fever are not available at present.
There is limited information regarding <i>Off-Label Guideline-Supported Use</i> of {{PAGENAME}} in adult patients.
* '''Urinary tract infections''', including [[pyelonephritis]] and [[cystitis]], caused by Escherichia coli, Proteus mirabilis, Klebsiella spp., and coagulase-negative staphylococci
<!--Non–Guideline-Supported Use (Adult)-->
* '''Skin and skin structure infections''' caused by Staphylococcus aureus and Streptococcus pyogenes
|offLabelAdultNoGuideSupport======Condition1=====
* Dosing Information
Appropriate culture and susceptibility studies should be performed to determine susceptibility of the causative organism to cefaclor.
:* Dosage
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefaclor and other antibacterial drugs, cefaclor should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
=====Condition2=====
==Dosage==
There is limited information regarding <i>Off-Label Non–Guideline-Supported Use</i> of {{PAGENAME}} in adult patients.
* The usual recommended daily dosage for pediatric patients is 20 mg/kg/day in divided doses every 8 hours. In more serious infections, [[otitis media]], and infections caused by less susceptible organisms, 40 mg/kg/day are recommended, with a maximum dosage of 1 g/day.
<!--Pediatric Indications and Dosage-->
* Cefaclor may be administered in the presence of impaired renal function. Under such a condition, the dosage usually is unchanged.
<!--FDA-Labeled Indications and Dosage (Pediatric)-->
* In the treatment of β-hemolytic streptococcal infections, a therapeutic dosage of cefaclor should be administered for at least 10 days.
|fdaLIADPed======Condition1=====
* Dosing Information
:* Dosage
=====Condition2=====
There is limited information regarding <i>FDA-Labeled Use</i> of {{PAGENAME}} in pediatric patients.
<!--Off-Label Use and Dosage (Pediatric)-->
<!--Guideline-Supported Use (Pediatric)-->
|offLabelPedGuideSupport======Condition1=====
|offLabelPedGuideSupport======Condition1=====
Line 105:
Line 112:
<!--Contraindications-->
<!--Contraindications-->
|contraindications=* Condition1
|contraindications=* Cefaclor is contraindicated in patients with known allergy to the cephalosporin group of antibiotics.
|warnings=* '''BEFORE THERAPY WITH CEFACLOR IS INSTITUTED, CAREFUL INQUIRY SHOULD BE MADE TO DETERMINE WHETHER THE PATIENT HAS HAD PREVIOUS HYPERSENSITIVITY REACTIONS TO CEFACLOR, CEPHALOSPORINS, PENICILLINS, OR OTHER DRUGS. IF THIS PRODUCT IS TO BE GIVEN TO PENICILLIN-SENSITIVE PATIENTS, CAUTION SHOULD BE EXERCISED BECAUSE CROSS-HYPERSENSITIVITY AMONG β-LACTAM ANTIBIOTICS HAS BEEN CLEARLY DOCUMENTED AND MAY OCCUR IN UP TO 10% OF PATIENTS WITH A HISTORY OF PENICILLIN ALLERGY'''.
<!--Warnings-->
|warnings=* Description
====Precautions====
* Description
<!--Adverse Reactions-->
<!--Clinical Trials Experience-->
|clinicalTrials=There is limited information regarding <i>Clinical Trial Experience</i> of {{PAGENAME}} in the drug label.
=====Body as a Whole=====
=====Cardiovascular=====
=====Digestive=====
=====Endocrine=====
=====Hematologic and Lymphatic=====
=====Metabolic and Nutritional=====
* '''IF AN ALLERGIC REACTION TO CEFACLOR OCCURS, DISCONTINUE THE DRUG. SERIOUS ACUTE HYPERSENSITIVITY REACTIONS MAY REQUIRE TREATMENT WITH EPINEPHRINE AND OTHER EMERGENCY MEASURES, INCLUDING OXYGEN, INTRAVENOUS FLUIDS, INTRAVENOUS ANTIHISTAMINES, CORTICOSTEROIDS, PRESSOR AMINES, AND AIRWAY MANAGEMENT, AS CLINICALLY INDICATED'''.
* Antibiotics, including cefaclor, should be administered cautiously to any patient who has demonstrated some form of allergy, particularly to drugs.
* '''Pseudomembranous colitis has been reported with nearly all antibacterial agents, including cefaclor, and has ranged in severity from mild to life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents'''.
=====Musculoskeletal=====
* Treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of clostridia. Studies indicate that a toxin produced by [[Clostridium difficile]] is one primary cause of antibiotic-associated [[colitis]].
* After the diagnosis of [[pseudomembranous colitis]] has been established, therapeutic measures should be initiated. Mild cases of [[pseudomembranous colitis]] usually respond to drug discontinuation alone. In moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation and treatment with an antibacterial drug effective against [[C. difficile]].
==PRECAUTIONS==
'''General'''
=====Neurologic=====
* Prescribing cefaclor in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
* Prolonged use of cefaclor may result in the overgrowth of non susceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate measures should be taken.
* Positive direct Coombs’ tests have been reported during treatment with the cephalosporin antibiotics. It should be recognized that a positive Coombs’ test may be due to the drug, e.g., in hematologic studies or in transfusion cross-matching procedures when antiglobulin tests are performed on the minor side or in Coombs’ testing of newborns whose mothers have received cephalosporin antibiotics before parturition.
* Cefaclor should be administered with caution in the presence of markedly impaired renal function. Since the half-life of cefaclor in anuria is 2.3 to 2.8 hours, dosage adjustments for patients with moderate or severe renal impairment are usually not required. Clinical experience with cefaclor under such conditions is limited; therefore, careful clinical observation and laboratory studies should be made.
=====Respiratory=====
* As with other β-lactam antibiotics, the renal excretion of cefaclor is inhibited by probenecid. Antibiotics, including cephalosporins, should be prescribed with caution in individuals with a history of gastrointestinal disease, particularly colitis.
|clinicalTrials=Adverse effects considered to be related to therapy with cefaclor are listed below:
* '''Hypersensitivity reactions''' have been reported in about 1.5% of patients and include morbilliform eruptions (1 in 100). Pruritus, urticaria, and positive Coombs’ tests each occur in less than 1 in 200 patients.
=====Skin and Hypersensitivy Reactions=====
* Cases of '''serum-sickness-like''' reactions have been reported with the use of cefaclor. These are characterized by findings of [[erythema multiforme]], [[rashes]], and other skin manifestations accompanied by [[arthritis]]/[[arthralgia]], with or without [[fever]], and differ from classic serum sickness in that there is infrequently associated lymphadenopathy and proteinuria, no circulating immune complexes, and no evidence to date of sequelae of the reaction. Occasionally, solitary symptoms may occur, but do not represent a serum-sickness-like reaction. While further investigation is ongoing, serum-sickness-like reactions appear to be due to hypersensitivity and more often occur during or following a second (or subsequent) course of therapy with cefaclor. Such reactions have been reported more frequently in pediatric ptients than in adults with an overall occurrence ranging from 1 in 200 (0.5%) in one focused trial to 2 in 8,346 (0.024%) in overall clinical trials (with an incidence in pediatric patients in clinical trials of 0.055%) to 1 in 38,000 (0.003%) in spontaneous event reports. Signs and symptoms usually occur a few days after initiation of therapy and subside within a few days after cessation of therapy; occasionally these reactions have resulted in hospitalization, usually of short duration (median hospitalization = 2 to 3 days, based on postmarketing surveillance studies). In those requiring hospitalization, the symptoms have ranged from mild to severe at the time of admission with more of the severe reactions occurring in pediatric patients. Antihistamines and glucocorticoids appear to enhance resolution of the signs and symptoms. No serious sequelae have been reported.
* More severe hypersensitivity reactions, including [[Stevens-Johnson syndrome]], [[toxic epidermal necrolysis]], and [[anaphylaxis]] have been reported rarely. Anaphylactoid events may be manifested by solitary symptoms, including [[angioedema]], [[asthenia]], [[edema]] (including face and limbs), [[dyspnea]], [[paresthesias]], [[syncope]], [[hypotension]], or vasodilatation. [[Anaphylaxis]] may be more common in patients with a history of penicillin allergy.
* Rarely, hypersensitivity symptoms may persist for several months.
'''Gastrointestinal symptoms''' occur in about 2.5% of patients and include [[diarrhea]] (1 in 70).
=====Special Senses=====
* Onset of [[pseudomembranous colitis]] symptoms may occur during or after antibiotic treatment. [[Nausea]] and [[vomiting]] have been reported rarely. As with some penicillins and some other cephalosporins, transient hepatitis and cholestatic [[jaundice]] have been reported rarely.
* Other effects considered related to therapy included eosinophilia (1 in 50 patients), genital [[pruritus]] , moniliasis or [[vaginitis]] (about 1 in 50 patients), and, rarely, [[thrombocytopenia]] or reversible [[interstitial nephritis]].
'''Causal Relationship Uncertain'''–
'''CNS'''–Rarely, reversible hyperactivity, agitation, [[nervousness]], insomnia, [[confusion]], [[hypertonia]], [[dizziness]], [[hallucinations]], and [[somnolence]] have been reported.
=====Urogenital=====
Transitory abnormalities in clinical laboratory test results have been reported. Although they were of uncertain etiology, they are listed below to serve as alerting information for the physician.
'''Hepatic'''–Slight elevations of AST, ALT, or alkaline phosphatase values (1 in 40).
'''Hematopoietic'''–As has also been reported with other β-lactam antibiotics, transient [[lymphocytosis]], [[leukopenia]], and, rarely, [[hemolytic anemia]], [[aplastic anemia]], [[agranulocytosis]], and reversible [[neutropenia]] of possible clinical significance.
There have been rare reports of increased prothrombin time with or without clinical bleeding in patients receiving cefaclor and [[warfarin]] concomitantly.
=====Miscellaneous=====
'''Renal'''– Slight elevations in BUN or serum creatinine (less than 1 in 500) or abnormal urinalysis (less than 1 in 200).
'''Cephalosporin-class Adverse Reactions'''
In addition to the adverse reactions listed above that have been observed in patients treated with cefaclor, the following adverse reactions and altered laboratory tests have been reported for cephalosporin-class antibiotics: [[fever]], [[abdominal pain]], superinfection, renal dysfunction, toxic nephropathy, hemorrhage, false positive test for urinary glucose, elevated bilirubin, elevated LDH, and [[pancytopenia]].
<!--Postmarketing Experience-->
Several cephalosporins have been implicated in triggering [[seizures]], particularly in patients with renal impairment when the dosage was not reduced. If [[seizures]] associated with drug therapy occur, the drug should be discontinued. Anticonvulsant therapy can be given if clinically indicated.
|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.
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Overview
Cefaclor is a {{{drugClass}}} that is FDA approved for the {{{indicationType}}} of {{{indication}}}. Common adverse reactions include .
Adult Indications and Dosage
FDA-Labeled Indications and Dosage (Adult)
Indications
Cefaclor is indicated in the treatment of the following infections when caused by susceptible strains of the designated microorganisms:
Otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, staphylococci, and Streptococcus pyogenes
Note: β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
Note: β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
Pharyngitis and Tonsillitis, caused by Streptococcus pyogenes
Note: Penicillin is the usual drug of choice in the treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cefaclor is generally effective in the eradication of streptococci from the nasopharynx; however, substantial data establishing the efficacy of cefaclor in the subsequent prevention of rheumatic fever are not available at present.
Urinary tract infections, including pyelonephritis and cystitis, caused by Escherichia coli, Proteus mirabilis, Klebsiella spp., and coagulase-negative staphylococci
Skin and skin structure infections caused by Staphylococcus aureus and Streptococcus pyogenes
Appropriate culture and susceptibility studies should be performed to determine susceptibility of the causative organism to cefaclor.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefaclor and other antibacterial drugs, cefaclor should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Dosage
The usual adult dosage is 250 mg every 8 hours. For more severe infections (such as pneumonia) or those caused by less susceptible organisms, doses may be doubled.
Cefaclor may be administered in the presence of impaired renal function. Under such a condition, the dosage usually is unchanged.
In the treatment of β-hemolytic streptococcal infections, a therapeutic dosage of cefaclor should be administered for at least 10 days.
Off-Label Use and Dosage (Adult)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Cefaclor in adult patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Cefaclor in adult patients.
Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
Indications
Cefaclor is indicated in the treatment of the following infections when caused by susceptible strains of the designated microorganisms:
Otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, staphylococci, and Streptococcus pyogenes
Note: β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
Note: β-lactamase-negative, ampicillin-resistant (BLNAR) strains of Haemophilus influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.
Pharyngitis and Tonsillitis, caused by Streptococcus pyogenes
Note: Penicillin is the usual drug of choice in the treatment and prevention of streptococcal infections, including the prophylaxis of rheumatic fever. Cefaclor is generally effective in the eradication of streptococci from the nasopharynx; however, substantial data establishing the efficacy of cefaclor in the subsequent prevention of rheumatic fever are not available at present.
Urinary tract infections, including pyelonephritis and cystitis, caused by Escherichia coli, Proteus mirabilis, Klebsiella spp., and coagulase-negative staphylococci
Skin and skin structure infections caused by Staphylococcus aureus and Streptococcus pyogenes
Appropriate culture and susceptibility studies should be performed to determine susceptibility of the causative organism to cefaclor.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of cefaclor and other antibacterial drugs, cefaclor should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Dosage
The usual recommended daily dosage for pediatric patients is 20 mg/kg/day in divided doses every 8 hours. In more serious infections, otitis media, and infections caused by less susceptible organisms, 40 mg/kg/day are recommended, with a maximum dosage of 1 g/day.
Cefaclor may be administered in the presence of impaired renal function. Under such a condition, the dosage usually is unchanged.
In the treatment of β-hemolytic streptococcal infections, a therapeutic dosage of cefaclor should be administered for at least 10 days.
Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
Condition1
Developed by:
Class of Recommendation:
Strength of Evidence:
Dosing Information
Dosage
Condition2
There is limited information regarding Off-Label Guideline-Supported Use of Cefaclor in pediatric patients.
Non–Guideline-Supported Use
Condition1
Dosing Information
Dosage
Condition2
There is limited information regarding Off-Label Non–Guideline-Supported Use of Cefaclor in pediatric patients.
Contraindications
Cefaclor is contraindicated in patients with known allergy to the cephalosporin group of antibiotics.
Warnings
BEFORE THERAPY WITH CEFACLOR IS INSTITUTED, CAREFUL INQUIRY SHOULD BE MADE TO DETERMINE WHETHER THE PATIENT HAS HAD PREVIOUS HYPERSENSITIVITY REACTIONS TO CEFACLOR, CEPHALOSPORINS, PENICILLINS, OR OTHER DRUGS. IF THIS PRODUCT IS TO BE GIVEN TO PENICILLIN-SENSITIVE PATIENTS, CAUTION SHOULD BE EXERCISED BECAUSE CROSS-HYPERSENSITIVITY AMONG β-LACTAM ANTIBIOTICS HAS BEEN CLEARLY DOCUMENTED AND MAY OCCUR IN UP TO 10% OF PATIENTS WITH A HISTORY OF PENICILLIN ALLERGY.
IF AN ALLERGIC REACTION TO CEFACLOR OCCURS, DISCONTINUE THE DRUG. SERIOUS ACUTE HYPERSENSITIVITY REACTIONS MAY REQUIRE TREATMENT WITH EPINEPHRINE AND OTHER EMERGENCY MEASURES, INCLUDING OXYGEN, INTRAVENOUS FLUIDS, INTRAVENOUS ANTIHISTAMINES, CORTICOSTEROIDS, PRESSOR AMINES, AND AIRWAY MANAGEMENT, AS CLINICALLY INDICATED.
Antibiotics, including cefaclor, should be administered cautiously to any patient who has demonstrated some form of allergy, particularly to drugs.
Pseudomembranous colitis has been reported with nearly all antibacterial agents, including cefaclor, and has ranged in severity from mild to life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents.
Treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of clostridia. Studies indicate that a toxin produced by Clostridium difficile is one primary cause of antibiotic-associated colitis.
After the diagnosis of pseudomembranous colitis has been established, therapeutic measures should be initiated. Mild cases of pseudomembranous colitis usually respond to drug discontinuation alone. In moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation and treatment with an antibacterial drug effective against C. difficile.
PRECAUTIONS
General
Prescribing cefaclor in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
Prolonged use of cefaclor may result in the overgrowth of non susceptible organisms. Careful observation of the patient is essential. If superinfection occurs during therapy, appropriate measures should be taken.
Positive direct Coombs’ tests have been reported during treatment with the cephalosporin antibiotics. It should be recognized that a positive Coombs’ test may be due to the drug, e.g., in hematologic studies or in transfusion cross-matching procedures when antiglobulin tests are performed on the minor side or in Coombs’ testing of newborns whose mothers have received cephalosporin antibiotics before parturition.
Cefaclor should be administered with caution in the presence of markedly impaired renal function. Since the half-life of cefaclor in anuria is 2.3 to 2.8 hours, dosage adjustments for patients with moderate or severe renal impairment are usually not required. Clinical experience with cefaclor under such conditions is limited; therefore, careful clinical observation and laboratory studies should be made.
As with other β-lactam antibiotics, the renal excretion of cefaclor is inhibited by probenecid. Antibiotics, including cephalosporins, should be prescribed with caution in individuals with a history of gastrointestinal disease, particularly colitis.
Adverse Reactions
Clinical Trials Experience
Adverse effects considered to be related to therapy with cefaclor are listed below:
Hypersensitivity reactions have been reported in about 1.5% of patients and include morbilliform eruptions (1 in 100). Pruritus, urticaria, and positive Coombs’ tests each occur in less than 1 in 200 patients.
Cases of serum-sickness-like reactions have been reported with the use of cefaclor. These are characterized by findings of erythema multiforme, rashes, and other skin manifestations accompanied by arthritis/arthralgia, with or without fever, and differ from classic serum sickness in that there is infrequently associated lymphadenopathy and proteinuria, no circulating immune complexes, and no evidence to date of sequelae of the reaction. Occasionally, solitary symptoms may occur, but do not represent a serum-sickness-like reaction. While further investigation is ongoing, serum-sickness-like reactions appear to be due to hypersensitivity and more often occur during or following a second (or subsequent) course of therapy with cefaclor. Such reactions have been reported more frequently in pediatric ptients than in adults with an overall occurrence ranging from 1 in 200 (0.5%) in one focused trial to 2 in 8,346 (0.024%) in overall clinical trials (with an incidence in pediatric patients in clinical trials of 0.055%) to 1 in 38,000 (0.003%) in spontaneous event reports. Signs and symptoms usually occur a few days after initiation of therapy and subside within a few days after cessation of therapy; occasionally these reactions have resulted in hospitalization, usually of short duration (median hospitalization = 2 to 3 days, based on postmarketing surveillance studies). In those requiring hospitalization, the symptoms have ranged from mild to severe at the time of admission with more of the severe reactions occurring in pediatric patients. Antihistamines and glucocorticoids appear to enhance resolution of the signs and symptoms. No serious sequelae have been reported.
Rarely, hypersensitivity symptoms may persist for several months.
Gastrointestinal symptoms occur in about 2.5% of patients and include diarrhea (1 in 70).
Onset of pseudomembranous colitis symptoms may occur during or after antibiotic treatment. Nausea and vomiting have been reported rarely. As with some penicillins and some other cephalosporins, transient hepatitis and cholestatic jaundice have been reported rarely.
Other effects considered related to therapy included eosinophilia (1 in 50 patients), genital pruritus , moniliasis or vaginitis (about 1 in 50 patients), and, rarely, thrombocytopenia or reversible interstitial nephritis.
Transitory abnormalities in clinical laboratory test results have been reported. Although they were of uncertain etiology, they are listed below to serve as alerting information for the physician.
Hepatic–Slight elevations of AST, ALT, or alkaline phosphatase values (1 in 40).
There have been rare reports of increased prothrombin time with or without clinical bleeding in patients receiving cefaclor and warfarin concomitantly.
Renal– Slight elevations in BUN or serum creatinine (less than 1 in 500) or abnormal urinalysis (less than 1 in 200).
Cephalosporin-class Adverse Reactions
In addition to the adverse reactions listed above that have been observed in patients treated with cefaclor, the following adverse reactions and altered laboratory tests have been reported for cephalosporin-class antibiotics: fever, abdominal pain, superinfection, renal dysfunction, toxic nephropathy, hemorrhage, false positive test for urinary glucose, elevated bilirubin, elevated LDH, and pancytopenia.
Several cephalosporins have been implicated in triggering seizures, particularly in patients with renal impairment when the dosage was not reduced. If seizures associated with drug therapy occur, the drug should be discontinued. Anticonvulsant therapy can be given if clinically indicated.
Postmarketing Experience
There is limited information regarding Postmarketing Experience of Cefaclor in the drug label.