CEFACLOR
Clinical safety rating: safe
Human studies have proved safety
Bactericidal; inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking.
| Metabolism | Hepatic (minor); primarily renally excreted unchanged. |
| Excretion | Renal: 60-85% unchanged in urine within 8 hours; biliary/fecal: minor, ~5% |
| Half-life | Terminal elimination half-life: 0.5-1 hour; prolonged to 2-3 hours in renal impairment |
| Protein binding | 25-50% bound to plasma proteins, primarily albumin |
| Volume of Distribution | 0.35-0.5 L/kg; distributes into most body tissues and fluids, including middle ear, sinus, and respiratory secretions |
| Bioavailability | Oral: 95% well absorbed; food does not significantly affect absorption |
| Onset of Action | Oral: 30-60 minutes to peak serum concentration; clinical effect typically within 1-2 hours |
| Duration of Action | 6-8 hours for susceptible organisms; dosing interval every 8 hours |
250-500 mg orally every 8 hours
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl 10-50 mL/min: 50% of usual dose every 8 hours; CrCl <10 mL/min: 50% of usual dose every 12 hours |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment; safety in severe impairment not established |
| Pediatric use | 20-40 mg/kg/day orally divided every 8 hours; maximum 1 g/day |
| Geriatric use | No specific adjustment, but monitor renal function; initiate at lower end of dosing range due to age-related renal decline |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Probenecid may decrease cephalosporin excretion Nephrotoxicity may occur with concurrent use of potent diuretics.
| Breastfeeding | Cefaclor is excreted into human breast milk in low concentrations (M/P ratio approximately 0.05-0.10). Considered compatible with breastfeeding by the American Academy of Pediatrics; use with caution in nursing infants with potential for diarrhea or allergic sensitization. |
| Teratogenic Risk | First trimester: No increased risk of major congenital malformations based on limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third trimester: No known fetal risks; Cefaclor crosses the placenta with fetal serum concentrations approximately 10-20% of maternal levels. |
■ FDA Black Box Warning
None.
| Common Effects | Diarrhea |
| Serious Effects |
["Known hypersensitivity to cephalosporins or any component","Previous immediate hypersensitivity reaction to penicillins (cross-sensitivity)"]
| Precautions | ["Hypersensitivity reactions, including anaphylaxis","Clostridium difficile-associated diarrhea","Seizures (especially with renal impairment)","Prolonged PT in patients on anticoagulants","False-positive urine glucose test"] |
| Food/Dietary | ["No significant food interactions; cefaclor can be taken with or without food.","Absorption may be slightly delayed with food but total bioavailability is unaffected.","Avoid grapefruit juice? No known interaction.","Alcohol: No specific interaction, but caution as it may increase side effects like gastrointestinal upset."] |
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| Fetal Monitoring | Monitor for signs of maternal hypersensitivity reactions; no specific fetal monitoring required. |
| Fertility Effects | No adverse effects on fertility observed in animal studies; human data not available. |
| Clinical Pearls | ["Cefaclor is a second-generation cephalosporin with activity against both Gram-positive and Gram-negative organisms, but not Pseudomonas or MRSA.","It is stable against some beta-lactamases, but resistance can occur via extended-spectrum beta-lactamases (ESBLs).","Dose adjustment is required in renal impairment (CrCl <40 mL/min).","It is available as an oral suspension and capsules; suspension must be refrigerated and shaken well before use.","Cefaclor may cause a serum sickness-like reaction, especially in children, characterized by rash, arthralgia, and fever.","It has a short half-life (0.6-0.9 hours) and is usually dosed every 8 hours.","Avoid use in patients with immediate hypersensitivity to penicillins due to cross-reactivity risk (about 10%)."] |
| Patient Advice | Take this medication exactly as prescribed, usually every 8 hours, with or without food. · Complete the full course of therapy even if you feel better to prevent bacterial resistance. · Shake the oral suspension well before each dose and refrigerate it; discard any unused portion after 14 days. · Contact your healthcare provider if you develop severe diarrhea, rash, joint pain, or fever. · Inform your doctor if you have a history of allergic reactions to penicillins or cephalosporins. · Do not take this medication if you are allergic to cefaclor or any other cephalosporin antibiotic. · If a dose is missed, take it as soon as remembered unless it is almost time for the next dose; do not double the dose. |