Cefaclor Side Effects

Please note - some side effects for Cefaclor may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Cefaclor - for the consumer

Cefaclor

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cefaclor:

Headache; mild diarrhea; nausea; sinus infection; tiredness; vomiting.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue; itching); bloody stools; fever; seizures; severe diarrhea; stomach cramps/pain; urge to have a bowel movement; vaginal irritation or discharge.

Cefaclor Capsules

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cefaclor Capsules:

Abnormal skin sensations; anal itching; difficulty breathing; fainting; fluid retention; flushing; headache; joint pain and inflammation; low blood pressure; mild diarrhea; nausea; secondary fungal infections, particularly of the oral, rectal, vaginal, and intestinal areas; sinus infection; skin redness; tiredness; vomiting; weakness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bloody stools; fever; seizures; severe diarrhea; stomach cramps/pain; urge to have a bowel movement; vaginal irritation or discharge.

Cefaclor Extended-Release Tablets

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cefaclor Extended-Release Tablets:

Headache; mild diarrhea; nausea; sinus infection; tiredness; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bloody stools; fever; seizures; severe diarrhea; stomach pain or cramps; urge to have a bowel movement; vaginal irritation or discharge.

Cefaclor Suspension

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Cefaclor Suspension:

Abnormal skin sensations; bloody stools; difficulty breathing; fainting; fluid retention; flushing; genital and anal itching; headache; joint pain and inflammation; low blood pressure; mild diarrhea; nausea; secondary fungal infections, particularly of the oral, rectal, vaginal, and intestinal areas; seizures; sinus infection; skin redness; tiredness; vomiting; weakness.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); bloody stools; fever; seizures; severe diarrhea; stomach cramps/pain; urge to have a bowel movement; vaginal irritation or discharge.

For the professional

Cefaclor

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 children 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 children 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 children. 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).

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 or vaginitis (less than 1 in 100 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.

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 Coumadin® 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.

Cefaclor Extended Release Tablets

Clinical Trials

There were 3272 patients treated with multiple doses of Cefaclor extended-release tablets in controlled clinical trials and an additional 211 subjects in pharmacology studies. There were no deaths in these trials thought to be related to toxicity from Cefaclor extended-release tablets. Treatment was discontinued in 1.7% of patients due to adverse events thought to be possibly or probably drug-related.

The following adverse clinical and laboratory events were reported during the Cefaclor extended-release tablets clinical trials conducted in North America at doses of 375 mg or 500 mg BID; however, relatedness of the adverse events to the drug was not assigned by clinical investigators during the trials.

Adverse reactions occurring during the clinical trials with Cefaclor extended-release tablets with an incidence of less than 1% but greater than 0.1% included the following (listed alphabetically):

Accidental injury, anorexia, anxiety, arthralgia, asthma, bronchitis, chest pain, chills, congestive heart failure, conjunctivitis, constipation, dizziness, dysmenorrhea, dyspepsia, dysuria, ear pain, edema, fever, flatulence, flu syndrome, gastritis, infection, insomnia, leukorrhea, lung disorder, maculopapular rash, malaise, menstrual disorder, myalgia, nausea and vomiting, neck pain, nervousness, nocturia, otitis media, pain, palpitation, peripheral edema, rash, respiratory disorder, sinusitis, somnolence, surgical procedure, sweating, tremor, urticaria, vomiting.

NOTE:One case of serum-sickness-like reaction was reported among the 3272 adult patients treated with Cefaclor extended-release tablets during the controlled clinical trials. These reactions have also been reported with the use of Cefaclor in other oral formulations and are seen more frequently in pediatric patients than in adults. These reactions are characterized by findings of erythema multiforme, rash, 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. 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 with overall occurrence ranging from 1 in 200 (0.5%) in one focused trial; to 2 in 8346 (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 patients 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.

In Postmarketing Experience

In addition to the events reported during clinical trials with Cefaclor extended-release tablets, the following adverse experiences are among those that have been reported during worldwide postmarketing surveillance: allergic reaction, anaphylactoid reaction, angioedema, face edema, hypotension, Stevens-Johnson syndrome, syncope, paresthesia, vasodilatation and vertigo.

Other Adverse Reactions Associated With Other Formulations of Cefaclor

In addition to the above, the following other adverse reactions and altered laboratory tests have been associated with Cefaclor in other oral formulations:

Clinical

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, edema (including face and limbs), paresthesias, syncope, or vasodilatation. Anaphylaxis may be more common in patients with a history of penicillin allergy. Rarely, hypersensitivity symptoms may persist for several months.

Symptoms of pseudomembranous colitis may appear either during or after antibiotic treatment.

Laboratory

Abnormal urinalysis, eosinophilia, leukopenia, neutropenia, transient elevations in AST, and transient thrombocytopenia have been reported.

Cephalosporin-Class Reactions

In addition to the adverse reactions listed above, the following adverse reactions and altered laboratory tests have been reported for cephalosporin-class antibiotics:

Clinical

Confusion, erythema multiforme, genital pruritus, hepatic dysfunction including cholestasis, hemolytic anemia, reversible hyperactivity, hypertonia, and reversible interstitial nephritis.

Laboratory

Positive direct Coombs’ test.

By body system

Gastrointestinal side effects

If diarrhea occurs and it is unresponsive to discontinuation of the drug and/or standard therapy, pseudomembranous colitis should be considered.

Gastrointestinal side effects have included diarrhea, nausea, vomiting, and abdominal pain. Extended-release cefaclor has been associated with diarrhea (3.8%), nausea (3.4%), and anorexia, constipation, dyspepsia, flatulence, gastritis, nausea and vomiting, and vomiting in 0.1% to 1% of patients. Pseudomembranous colitis has been reported in patients treated with cephalosporins.

Hypersensitivity side effects

Anaphylactic reactions are rare, but may occur, especially in patients with a history of penicillin allergy.

Serum-sickness-like reactions are more frequent in pediatric patients and following a second or subsequent course of cefaclor and have been characterized by erythema multiforme, rash, arthritis, and/or arthralgia with or without fever.

Hypersensitivity reactions have included rash, morbilliform eruptions (1%), pruritus, serum-sickness-like reactions, urticaria, anaphylactic reaction, Stevens-Johnson syndrome, toxic epidermal necrolysis, anaphylactoid reaction, and angioedema.

Hepatic side effects

Hepatic side effects have included slight elevations AST, ALT, and alkaline phosphatase in 2.5% of patients. Extended-release cefaclor has been associated with increased ALT (0.3%), increased alkaline phosphatase (0.3%), increased bilirubin (0.3%), increased creatine phosphokinase (0.7%), and increased GGT (0.2%). Cephalosporins as a class have been associated with elevated LDH, hepatic dysfunction, and cholestasis.

Renal side effects

Renal side effects have included transient elevations in blood urea nitrogen (BUN) and serum creatinine in 0.2% of patients, reversible interstitial nephritis (rare), and abnormal urinalysis (0.5%). Extended-release cefaclor has been associated with increased BUN (0.2%), and increased creatinine (0.5%). Cephalosporins as a class have been associated with toxic nephropathy, reversible interstitial nephritis, and renal dysfunction.

One case report of acute interstitial nephritis and nonoliguric renal failure has been reported following cefaclor therapy. (Reversible fever, azotemia, pyuria, and eosinophiluria are the hallmarks of cephalosporin-induced interstitial nephritis.)

Hematologic side effects

Hematologic side effects have included eosinophilia (2%), positive Coombs' test (less than 0.5%), leukopenia, thrombocytosis, transient thrombocytopenia (rare), transient lymphocytosis, hemolytic anemia, aplastic anemia, agranulocytosis, and reversible neutropenia. Extended-release cefaclor has been associated with increased eosinophils (0.3%), decreased erythrocyte count (0.3%), decreased hemoglobin (0.2%), decreased lymphocytes (0.3%), increased mean cell volume (0.7%), decreased segmented neutrophils (0.3%), and decreased platelet count (0.4%). Cephalosporins as a class have been associated with hemorrhage and pancytopenia.

Genitourinary side effects

Genitourinary side effects have included genital pruritus and vaginitis in less than 1% of patients. Extended-release cefaclor has been associated with vaginitis (2.4%) and vaginal moniliasis (2.2%), and dysmenorrhea, dysuria, leukorrhea, menstrual disorder, and nocturia in 0.1% to 1% of patients. Cephalosporins as a class have been associated with false-positive tests for urine glucose.

Nervous system side effects

Nervous system side effects have rarely included reversible hyperactivity, agitation, nervousness, insomnia, confusion, hypertonia, dizziness, hallucinations, and somnolence. Extended release cefaclor has been associated with headache in 4.9% of patients, and dizziness, insomnia, nervousness, somnolence, and tremor in 0.1% to 1% of patients, and paresthesia and vertigo. Some cephalosporins have been associated with seizures, primarily when dosages were not reduced in renally impaired patients.

Other side effects

Other side effects associated with extended-release cefaclor have included abdominal pain (1.6%), back pain (1%), and accidental injury, chest pain, chills, ear pain, fever, flu syndrome, infection, malaise, neck pain, otitis media, pain, and surgical procedure in 0.1% to 1% of patients. Cephalosporins as a class have been associated with abdominal pain, fever, and superinfection.

Respiratory side effects

Respiratory side effects associated with extended-release cefaclor have included rhinitis (3.9%), increased cough (1.5%), pharyngitis (1.4%), and asthma, bronchitis, lung disorder, respiratory disorder, and sinusitis in 0.1% to 1% of patients.

Dermatologic side effects

Dermatologic side effects have included pruritus, maculopapular rash, rash, and urticaria.

Musculoskeletal side effects

Musculoskeletal side effects associated with extended-release cefaclor have included arthralgia and myalgia in 0.1% to 1% of patients.

Cardiovascular side effects

Cardiovascular side effects associated with extended-release cefaclor have included congestive heart failure (0.1% to 1%), edema (0.1% to 1%), palpitation (0.1% to 1%), peripheral edema (0.1% to 1%), hypotension, face edema, vasodilatation, and syncope.

Ocular side effects

Ocular side effects associated with extended-release cefaclor have included conjunctivitis (0.1% to 1%).

Endocrine side effects

Endocrine side effects associated with extended-release cefaclor have included sweating (0.1% to 1%).

Metabolic side effects

Metabolic side effects associated with extended-release cefaclor have included decreased albumin (0.3%), decreased calcium (0.7%), increased creatine phosphokinase (0.7%), increased phosphorus (0.7%), increased potassium (0.4%), decreased sodium (0.3%), and increased sodium (0.4%).

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