Usage
Cefaclor is a second-generation cephalosporin antibiotic prescribed for bacterial infections such as:
- Lower respiratory tract infections (e.g., pneumonia, bronchitis)
- Upper respiratory tract infections (e.g., pharyngitis, tonsillitis, sinusitis, otitis media)
- Skin and skin structure infections (e.g., impetigo, cellulitis)
- Urinary tract infections (e.g., cystitis, pyelonephritis)
- Gonococcal urethritis
Its pharmacological classification is antibiotic.
Cefaclor’s mechanism of action involves inhibiting bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). This leads to cell lysis mediated by bacterial autolytic enzymes.
Alternate Names
Cefaclor is also known by various brand names, including Ceclor, Distaclor, Keflor, Raniclor, and Biocef.
How It Works
Pharmacodynamics: Cefaclor exerts its bactericidal effect by disrupting bacterial cell wall synthesis. It binds to PBPs, which are essential enzymes for the final stages of peptidoglycan synthesis. This binding inhibits cross-linking of peptidoglycan chains, weakening the cell wall and ultimately leading to bacterial cell death.
Pharmacokinetics: Cefaclor is well-absorbed orally, with or without food, although food may delay peak plasma concentrations. It is widely distributed throughout the body, including the middle ear fluid and sputum. Cefaclor undergoes minimal metabolism and is primarily excreted unchanged in the urine. The elimination half-life is approximately 0.6 to 0.9 hours in patients with normal renal function, but may be prolonged in those with renal impairment.
Mode of Action: Cefaclor’s mode of action is through the inhibition of bacterial cell wall synthesis by binding to specific PBPs inside the bacterial cell wall. This inhibits the third and last stage of bacterial cell wall synthesis, leading to cell lysis through bacterial cell wall autolytic enzymes.
Elimination: Cefaclor is primarily eliminated via renal excretion.
Dosage
Standard Dosage
Adults:
- Mild to Moderate Infections: 250 mg orally every 8 hours or 375 mg orally every 12 hours.
- More Severe Infections: 500 mg orally every 8 hours or 750 mg orally every 12 hours.
- Maximum Daily Dose: 4 g.
Children:
- Ages >1 month: 20 mg/kg/day orally in divided doses every 8 hours. For otitis media and pharyngitis, the total daily dose may be divided and administered every 12 hours.
- Serious Infections: 40 mg/kg/day orally in divided doses every 8-12 hours. Maximum dose is 1 g/day.
- Safety and efficacy have not been established in infants <1 month old.
Special Cases:
- Elderly Patients: Dose adjustments may be necessary due to age-related decline in renal function. Consider monitoring renal function.
- Patients with Renal Impairment: Dose adjustment may be necessary in patients with moderate to severe renal impairment. For patients undergoing hemodialysis, administer a loading dose prior to dialysis, followed by maintenance doses during interdialytic periods.
- Patients with Hepatic Dysfunction: No dosage adjustments are typically recommended.
- Patients with Comorbid Conditions: Careful monitoring and dose adjustment may be necessary based on specific comorbid conditions and their impact on drug clearance.
Clinical Use Cases
Cefaclor’s use in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations is not routinely indicated. Its primary role is in the treatment of infections as outlined above.
Dosage Adjustments
Dose modifications are generally based on renal function. Monitoring serum creatinine and creatinine clearance is recommended, especially in elderly patients and those with known renal impairment. Genetic polymorphisms affecting drug metabolism are not commonly considered for cefaclor dosing adjustments.
Side Effects
Common Side Effects
- Diarrhea
- Nausea
- Vomiting
- Rash
- Vaginal yeast infection
- Oral thrush (candidiasis)
Rare but Serious Side Effects
- Serum sickness-like reaction (especially in children)
- Pseudomembranous colitis
- Severe allergic reactions (anaphylaxis)
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Hemolytic anemia
- Interstitial nephritis
- Hepatic dysfunction
- Seizures
Long-Term Effects
Prolonged cefaclor use may increase the risk of Clostridium difficile infection and the development of antibiotic resistance.
Adverse Drug Reactions (ADR)
Clinically significant ADRs include severe allergic reactions, severe skin reactions, Clostridium difficile-associated diarrhea, and blood dyscrasias. These require immediate medical intervention.
Contraindications
- Known hypersensitivity to cephalosporins or any component of the formulation.
Drug Interactions
- Probenecid: Decreases renal excretion of cefaclor, leading to increased serum levels.
- Oral anticoagulants (e.g., warfarin): May enhance anticoagulant effects.
- Hormonal contraceptives: Efficacy may be reduced.
- Bacteriostatic antibiotics: May antagonize the bactericidal effect of cefaclor.
Pregnancy and Breastfeeding
Cefaclor is classified as Pregnancy Category B. Animal studies have not shown evidence of fetal harm, but there are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if clearly needed. Cefaclor is excreted in breast milk in small amounts. While generally considered compatible with breastfeeding, monitor the infant for diarrhea or thrush.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial cell wall synthesis by binding to PBPs.
- Side Effects: Diarrhea, nausea, rash, allergic reactions. Serious side effects include severe skin reactions, C. difficile infection, and anaphylaxis.
- Contraindications: Hypersensitivity to cephalosporins.
- Drug Interactions: Probenecid, oral anticoagulants, hormonal contraceptives.
- Pregnancy & Breastfeeding: Category B; use with caution. Excreted in breast milk.
- Dosage: Adults: 250-500 mg every 8 hours. Children: 20-40 mg/kg/day divided every 8 hours.
- Monitoring Parameters: Renal function (serum creatinine, creatinine clearance), signs of superinfection (e.g., diarrhea, thrush), and allergic reactions.
Popular Combinations
Cefaclor is not typically used in combination with other antibiotics.
Precautions
- General Precautions: Assess for allergies to cephalosporins and penicillins. Monitor renal function, particularly in elderly patients and those with pre-existing renal impairment. Be aware of the potential for C. difficile infection with prolonged use.
- Specific Populations: Use with caution in pregnant and breastfeeding women. Dosage adjustment may be needed in patients with renal impairment.
- Lifestyle Considerations: Alcohol consumption may exacerbate gastrointestinal side effects. No specific restrictions on driving or operating machinery are typically associated with cefaclor, unless the patient experiences side effects such as dizziness.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Cefaclor?
A: Adults: 250-500 mg every 8 hours or 375-750 mg every 12 hours. Children: 20-40 mg/kg/day divided every 8-12 hours.
Q2: What are the common side effects of Cefaclor?
A: Common side effects include diarrhea, nausea, vomiting, rash, and fungal infections (oral thrush, vaginal yeast infections).
Q3: What are the serious side effects of Cefaclor?
A: Serious side effects include severe allergic reactions (anaphylaxis), pseudomembranous colitis, Stevens-Johnson syndrome, toxic epidermal necrolysis, and blood dyscrasias.
Q4: Is Cefaclor safe to use during pregnancy?
A: Cefaclor is a Pregnancy Category B drug. Use only if clearly needed and after careful consideration of risks and benefits.
Q5: Can Cefaclor be used while breastfeeding?
A: Cefaclor is excreted in breast milk in small amounts. Monitor the infant for potential side effects like diarrhea or thrush.
Q6: How does Cefaclor interact with other medications?
A: Cefaclor may interact with probenecid, oral anticoagulants, and hormonal contraceptives. It may also interact with other antibiotics. Consult a drug interaction checker for a complete list of potential interactions.
Q7: What should I do if a patient experiences an allergic reaction to Cefaclor?
A: Discontinue the drug immediately and provide appropriate medical care, which may include epinephrine, antihistamines, and corticosteroids.
Q8: What is the mechanism of action of Cefaclor?
A: Cefaclor inhibits bacterial cell wall synthesis by binding to PBPs, ultimately leading to bacterial cell death.
Q9: What infections is Cefaclor used to treat?
A: Cefaclor is used to treat various bacterial infections, including respiratory tract infections (pneumonia, bronchitis, sinusitis, pharyngitis, tonsillitis, otitis media), skin and skin structure infections (impetigo, cellulitis), urinary tract infections (cystitis, pyelonephritis), and gonococcal urethritis.
Q10: How is Cefaclor administered?
A: Cefaclor is administered orally, as capsules, tablets, or oral suspension.
