Cefaclor is a second-generation cephalosporin antibiotic indicated for the treatment of a wide range of bacterial infections caused by susceptible strains of microorganisms. It exerts its bactericidal effect by inhibiting bacterial cell wall synthesis, leading to osmotic instability and cell lysis. This oral formulation offers broad-spectrum coverage against both gram-positive and gram-negative bacteria, making it a versatile option in outpatient and community-acquired infection management. Its pharmacokinetic profile allows for convenient dosing regimens, supporting patient adherence and therapeutic success.

Features

• Active ingredient: Cefaclor (as cefaclor monohydrate)
• Drug class: Second-generation cephalosporin antibiotic
• Administration: Oral (capsules, tablets, or oral suspension)
• Mechanism: Inhibition of bacterial cell wall synthesis via binding to penicillin-binding proteins
• Spectrum: Broad-spectrum activity against gram-positive and gram-negative bacteria
• Formulations: 250 mg and 500 mg capsules; 125 mg/5 mL, 187 mg/5 mL, 250 mg/5 mL, and 375 mg/5 mL oral suspensions
• Bioavailability: Well-absorbed from the gastrointestinal tract, not significantly affected by food
• Half-life: Approximately 0.6–0.9 hours in adults with normal renal function
• Metabolism: Minimally metabolized, primarily excreted unchanged in urine
• Pregnancy category: B (animal reproduction studies have not demonstrated fetal risk but there are no adequate studies in pregnant women)

Benefits

• Provides effective treatment for common bacterial infections including respiratory tract, skin, and urinary tract infections
• Offers convenient oral administration suitable for outpatient treatment, potentially reducing hospitalization needs
• Demonstrates reliable bactericidal activity against both gram-positive and gram-negative organisms
• Features generally good tolerability with an established safety profile in appropriate patient populations
• Allows for flexible dosing regimens that can be adjusted based on infection severity and renal function
• Maintains activity against beta-lactamase producing strains of Haemophilus influenzae and Moraxella catarrhalis

Common use

Cefaclor is commonly prescribed for the treatment of bacterial infections caused by susceptible microorganisms. Primary indications include pharyngitis and tonsillitis caused by Streptococcus pyogenes, otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, and staphylococci, lower respiratory tract infections including pneumonia caused by S. pneumoniae, H. influenzae, and S. pyogenes, urinary tract infections caused by Escherichia coli, Proteus mirabilis, Klebsiella species, and coagulase-negative staphylococci, and skin and skin structure infections caused by S. aureus and S. pyogenes. It may also be used for the treatment of uncomplicated gonorrhea when caused by penicillinase-producing Neisseria gonorrhoeae.

Dosage and direction

The dosage of cefaclor should be adjusted based on the severity of infection, susceptibility of the causative microorganisms, and the patient’s renal function. For adults, the usual dose is 250 mg every 8 hours. For more severe infections or those caused by less susceptible organisms, doses may be increased to 500 mg every 8 hours or 500 mg every 12 hours, with a maximum daily dose of 4 grams. For children, the recommended daily dose is 20–40 mg/kg/day in divided doses every 8 or 12 hours, not to exceed 1 gram per day. The oral suspension should be shaken well before each use. Cefaclor may be administered without regard to meals, though administration with food may minimize gastrointestinal upset. For patients with impaired renal function, dosage adjustments are necessary: for creatinine clearance of 10–50 mL/min, administer 50–100% of the normal dose at standard intervals; for creatinine clearance less than 10 mL/min, administer 50% of the normal dose at standard intervals.

Precautions

Before prescribing cefaclor, carefully consider patient history of hypersensitivity reactions to cephalosporins, penicillins, or other drugs. Use with caution in patients with history of gastrointestinal disease, particularly colitis. Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi. Monitor renal function periodically during therapy in patients with pre-existing renal impairment. Positive direct Coombs tests have been reported during treatment with cephalosporins. Cefaclor should be prescribed with caution in breastfeeding women as it is excreted in human milk. In patients with diabetes, cefaclor suspension contains sucrose which should be considered in dietary management. False-positive reactions for glucose in the urine may occur with Benedict’s or Fehling’s solutions but not with enzyme-based tests.

Contraindications

Cefaclor is contraindicated in patients with known hypersensitivity to cefaclor or other cephalosporin antibiotics. It should not be administered to patients who have experienced anaphylactic reactions to penicillins due to the potential for cross-reactivity. The drug is contraindicated in patients with a history of severe immediate hypersensitivity reactions to beta-lactam antibiotics. Use is also contraindicated in patients with known phenylketonuria when using formulations containing phenylalanine.

Possible side effect

The most commonly reported adverse reactions associated with cefaclor include gastrointestinal disturbances such as diarrhea (2–3%), nausea (1–2%), and vomiting (1%). Hypersensitivity reactions may occur, including maculopapular rash (1–2%), urticaria (0.5%), and pruritus. Transient elevations in liver enzymes have been observed in some patients. Less common side effects include headache, dizziness, fatigue, and vaginitis. Serum sickness-like reactions characterized by arthralgia, fever, rash, and lymphadenopathy have been reported, particularly in children. As with other broad-spectrum antibiotics, pseudomembranous colitis caused by Clostridium difficile may occur. Hematologic effects including transient leukopenia, neutropenia, and eosinophilia have been reported rarely.

Drug interaction

Probenecid may decrease renal tubular secretion of cefaclor, resulting in increased and prolonged blood levels. Concurrent administration with other nephrotoxic drugs may increase the risk of renal toxicity. Cefaclor may reduce the effectiveness of oral contraceptives; additional contraceptive methods should be used during treatment. Administration with warfarin may potentiate anticoagulant effects, requiring closer monitoring of prothrombin time. False-positive reactions for glucose in the urine may occur with certain tests. The absorption of cefaclor may be delayed when administered with aluminum- or magnesium-containing antacids.

Missed dose

If a dose of cefaclor is missed, it should be taken as soon as remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not double the dose to make up for a missed one. Maintaining consistent blood levels is important for therapeutic efficacy, so adherence to the prescribed dosing schedule is recommended. If multiple doses are missed, patients should contact their healthcare provider for guidance.

Overdose

Symptoms of cefaclor overdose may include nausea, vomiting, epigastric distress, and diarrhea. In cases of significant overdose, particularly in patients with renal impairment, neurotoxic reactions including seizures may occur. Management should include gastric lavage or emesis if ingestion was recent, followed by supportive measures. Hemodialysis may be effective in removing cefaclor from the bloodstream, particularly in patients with renal impairment. Serum levels of cefaclor can be measured if quantitative assessment is needed. Patients should receive symptomatic treatment for gastrointestinal distress and be monitored for signs of electrolyte imbalance or dehydration.

Storage

Cefaclor capsules and tablets should be stored at controlled room temperature, 20–25°C (68–77°F), in a tightly closed container, and protected from moisture. The oral suspension, once reconstituted, should be stored in the refrigerator between 2–8°C (36–46°F) and discarded after 14 days. Keep all medications out of reach of children. Do not freeze the oral suspension. Protect from light and excessive heat. Do not use the medication if it has changed color or contains particulate matter.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. The prescribing physician should be consulted for diagnosis and treatment of medical conditions. Dosage must be individualized based on the patient’s condition, renal function, and susceptibility of the causative organisms. The complete prescribing information should be reviewed before initiating therapy. Antibiotics should only be used to treat bacterial infections and are not effective against viral infections. Improper use may lead to the development of drug-resistant bacteria.

Reviews

Clinical studies have demonstrated cefaclor’s efficacy in treating various bacterial infections, with success rates typically exceeding 85% for approved indications. In comparative trials, cefaclor has shown similar efficacy to other oral cephalosporins for respiratory tract infections. The drug is generally well-tolerated, with most adverse effects being mild and self-limiting. Some clinicians note the convenience of twice-daily dosing for certain formulations, which may improve adherence. However, the emergence of resistant organisms has limited its use in some geographic areas. Patient satisfaction surveys indicate good acceptance of the taste of the oral suspension, particularly important for pediatric populations. Long-term clinical experience spanning decades supports its position as a reliable option for community-acquired infections when prescribed appropriately.