CEPHRADINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CEPHRADINE (CEPHRADINE).
Cephradine is a first-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.
| Metabolism | Cephradine is minimally metabolized in the liver; the majority of the drug is excreted unchanged in the urine via glomerular filtration and tubular secretion. |
| Excretion | Primarily renal (≥90% unchanged via glomerular filtration and tubular secretion); minor biliary/fecal (<10%). |
| Half-life | Terminal elimination half-life 0.5–1.5 hours (normal renal function); prolonged to 6–15 hours in severe renal impairment (CrCl <10 mL/min). |
| Protein binding | 6–20% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Vd 0.25–0.5 L/kg; reflects distribution into extracellular fluid and tissues (e.g., kidney, liver). |
| Bioavailability | Oral: >90% (capsules and suspension); IM: approximately 100%. |
| Onset of Action | Oral: 30–60 minutes; IM: 15–30 minutes; IV: immediate. |
| Duration of Action | 6–12 hours (dose-dependent; sustained for susceptible organisms). |
| Molecular Weight | 349.4 Da |
250-500 mg orally every 6 hours; 500 mg to 1 g intramuscularly or intravenously every 6 hours. Maximum: 4 g/day.
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl >50 mL/min: no adjustment; CrCl 25-50 mL/min: 500 mg every 6 hours; CrCl 10-25 mL/min: 500 mg every 12 hours; CrCl <10 mL/min: 500 mg every 24 hours. |
| Liver impairment | No dose adjustment required as cephradine is primarily renally eliminated. Use with caution in severe hepatic impairment. |
| Pediatric use | Children >9 months: 25-50 mg/kg/day orally in 4 divided doses; 50-100 mg/kg/day intramuscularly or intravenously in 4 divided doses. Maximum: 4 g/day. |
| Geriatric use | Dose based on renal function. Start at lower end of dosing range and monitor renal function. |
| 1st trimester | Cephradine crosses the placenta with detectable fetal serum levels. Animal studies have not shown teratogenicity, but adequate human studies are lacking. Use cautiously if benefit outweighs risk. |
| 2nd trimester | Same as t1; no known teratogenic risk. Use for infections where clearly indicated. |
| 3rd trimester | Safe; used for maternal infections. Consider risk of neonatal diarrhea due to gut flora alteration. |
Clinical note
Comprehensive clinical and safety monograph for CEPHRADINE (CEPHRADINE).
| Placental transfer | Cephradine crosses the placenta with fetal-to-maternal serum concentration ratios of 0.2-0.5. Achieves therapeutic levels in fetal tissues. |
| Breastfeeding | Cephradine is excreted into breast milk in small amounts (approximately 0.5-1% of maternal dose). Generally considered compatible with breastfeeding; monitor infant for potential gastrointestinal effects (diarrhea, candidiasis). |
■ FDA Black Box Warning
There is no FDA black box warning for cephradine.
| Serious Effects |
Hypersensitivity to cephradine or other cephalosporinsHistory of immediate-type hypersensitivity reaction to penicillins (cross-sensitivity)
| Precautions | Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) may occur, especially in patients with a history of penicillin allergy., Clostridium difficile-associated diarrhea (CDAD) has been reported; consider in patients who develop diarrhea., Dosage adjustment required in renal impairment., Prolonged use may result in superinfection with non-susceptible organisms., Use with caution in patients with a history of gastrointestinal disease, particularly colitis. |
| Food/Dietary | Food delays absorption; avoid taking with meals. No specific food-drug interactions reported. |
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| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | Cephradine is a first-generation cephalosporin. Animal studies have not revealed evidence of teratogenicity or fetal harm. However, there are no adequate and well-controlled studies in pregnant women. Cephalosporins are generally considered low risk; however, due to limited human data, it should be used during pregnancy only if clearly needed. The FDA pregnancy category is B. No specific fetal risks are known for any trimester. |
| Fetal Monitoring | Monitor for signs of maternal hypersensitivity reactions (rash, anaphylaxis), gastrointestinal disturbances, and superinfection. Fetal monitoring not routinely required. In prolonged therapy, monitor renal and hepatic function. |
| Fertility Effects | No adverse effects on male or female fertility have been reported in animal studies. Human data are lacking. No known impact on reproduction. |
| Clinical Pearls | Cephradine is a first-generation cephalosporin with activity similar to cephalexin. It is susceptible to hydrolysis by beta-lactamases, limiting coverage against Staphylococcus aureus. Administer on an empty stomach (1 hour before or 2 hours after meals) to maximize absorption. Dose adjustment required in renal impairment (CrCl <50 mL/min). May cause false-positive direct Coombs test and urine glucose tests using copper reduction methods. |
| Patient Advice | Take this medication on an empty stomach, at least 1 hour before or 2 hours after meals. · Complete the full course even if you feel better to prevent resistance. · Report any signs of allergy (rash, itching, swelling, difficulty breathing) immediately. · Notify your doctor if you have kidney disease or a history of penicillin allergy. · Do not stop abruptly without consulting your physician. |