Cefaclor Drug Information

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 (see TABLES 4 and 5 ). Table 4: ADVERSE CLINICAL EVENTS - CEFACLOR EXTENDED-RELEASE TABLETS MULTIPLE DOSE DOSING REGIMENS CLINICAL TRIALS - NORTH AMERICA (n = 1400) Incidence Equal to or Greater Than 1% Event Incidence Headache 4.9% Rhinitis 3.9% Diarrhea 3.8% Nausea 3.4% Vaginitis n = 934 for these events (subset of female participants). 2.4% Vaginal Moniliasis 2.2% Abdominal Pain 1.6% Cough Increased 1.5% Pharyngitis 1.4% Pruritus 1.4% Back Pain 1.0% 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. Table 5: ADVERSE CLINICAL LABORATORY EVENTS CEFACLOR EXTENDED-RELEASE TABLETS MULTIPLE DOSE DOSING REGIMENS CLINICAL TRIALS – NORTH AMERICA Event Incidence Incidence Less Than 1%, but Greater Than 0.1% Albumin decreased 0.3% Alkaline phosphatase increased 0.3% ALT/SGPT increased 0.3% Bilirubin total increased 0.3% Blood urea nitrogen (BUN) increased 0.2% Calcium decreased 0.7% Creatine phosphokinase increased 0.7% Creatinine increased 0.5% Eosinophils increased 0.3% Erythrocyte count decreased 0.3% GGT increased 0.2% Hemoglobin decreased 0.2% Lymphocytes decreased 0.3% Mean Cell Volume (MCV) increased 0.7% Neutrophils segmented decreased 0.3% Phosphorous increased 0.7% Platelet count decreased 0.3% Potassium increased 0.4% Sodium decreased 0.3% Sodium increased 0.4% 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. (See WARNINGS.) 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.

Drug Interactions Antacids The extent of absorption of cefaclor extended-release tablets is diminished if magnesium or aluminum hydroxide-containing antacids are taken within 1 hour of administration; H 2 blockers do not alter either the rate or the extent of absorption of cefaclor extended-release tablets. Probenecid The renal excretion of cefaclor is inhibited by probenecid. Warfarin There have been rare reports of increased prothrombin time with or without clinical bleeding in patients receiving cefaclor and warfarin concomitantly.

No specific studies have been performed to rule in or rule out this potential drug/drug interaction.

Usage in Pregnancy Teratogenic Effect Reproduction studies using cefaclor have been performed in mice, rats and ferrets at doses up to 3 to 5 times the maximum human dose (1500 mg/day) based on mg/m 2. These studies have revealed no harm to the fetus due to cefaclor. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, cefaclor extended-release tablets should be used during pregnancy only if clearly needed.

Pediatric Use Safety and effectiveness of cefaclor extended-release tablets in pediatric patients less than 16 years of age have not been established.

Cefaclor extended-release tablets are contraindicated in patients with known hypersensitivity to cefaclor and other cephalosporins.

The toxic symptoms following an overdose of cefaclor may include nausea, vomiting, epigastric distress, and diarrhea. The severity of the epigastric distress and the diarrhea are dose-related. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which, in many cases, is more effective than emesis or lavage.

Consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Although cefaclor is considered dialyzable, neither forced diuresis, peritoneal dialysis, hemodialysis, nor charcoal hemoperfusion have been demonstrated to be beneficial in an overdose of cefaclor.