VELOSEF '500'
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VELOSEF '500' (VELOSEF '500').
Cephradine inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting the final transpeptidation step of peptidoglycan synthesis, leading to cell lysis and death. It is a first-generation cephalosporin with bactericidal activity.
| Metabolism | Cephradine is not extensively metabolized; it is primarily excreted unchanged in urine via glomerular filtration and tubular secretion. A small amount may be metabolized via hydrolysis of the beta-lactam ring. No significant hepatic metabolism. |
| Excretion | Renal excretion of unchanged drug: >90% (glomerular filtration and tubular secretion); biliary/fecal: <1% |
| Half-life | Terminal elimination half-life: 1.2 hours in adults with normal renal function; prolonged to 8-15 hours in severe renal impairment (CrCl <10 mL/min); clinical context: dosing interval adjustment required for renal impairment |
| Protein binding | 10-15% bound to plasma proteins (primarily albumin) |
| Volume of Distribution | 0.2-0.3 L/kg; clinical meaning: distributes primarily into extracellular fluid; low Vd consistent with limited tissue penetration |
| Bioavailability | Oral: 90-95% (well absorbed); intramuscular: 100% (complete absorption) |
| Onset of Action | Oral: 30-60 minutes (therapeutic serum levels); intramuscular: 15-30 minutes; intravenous: immediate |
| Duration of Action | 6-12 hours (depending on renal function and dose); clinical note: requires twice-daily or thrice-daily dosing in normal renal function |
| Molecular Weight | 423.5 |
500 mg orally every 6 hours for 10 days.
| Dosage form | CAPSULE |
| Renal impairment | For CrCl 20-30 mL/min: 500 mg every 12 hours. For CrCl 10-19 mL/min: 500 mg every 24 hours. For CrCl <10 mL/min: 500 mg every 36 hours. Hemodialysis: 500 mg after dialysis. |
| Liver impairment | No dose adjustment recommended for hepatic impairment as drug is renally excreted. |
| Pediatric use | Children >1 month: 25-50 mg/kg/day in divided doses every 6 hours. Maximum 500 mg/dose. |
| Geriatric use | No specific dose adjustment; monitor renal function and reduce dose per renal adjustment guidelines. |
| 1st trimester | Limited human data; animal studies show no evidence of harm. Use only if clearly needed. |
| 2nd trimester | Generally considered safe; no known teratogenic effects. |
| 3rd trimester | Safe; no known risks to fetus or neonate. |
Clinical note
Comprehensive clinical and safety monograph for VELOSEF '500' (VELOSEF '500').
| Placental transfer | Crosses the placenta; fetal levels are lower than maternal levels. |
| Breastfeeding | Excreted into breast milk in low concentrations; considered compatible with breastfeeding. |
| Lactation Rating | L1 (Safe) |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to cephalosporinsHypersensitivity to penicillins (potential cross-reactivity)
| Precautions | Hypersensitivity reactions: Cross-allergenicity with penicillins and other beta-lactams; serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported., Antibiotic-associated pseudomembranous colitis (Clostridioides difficile infection) can occur with use., Renal impairment: Dosage adjustment required in patients with creatinine clearance <30 mL/min to avoid accumulation and neurotoxicity., Prolonged use may result in overgrowth of nonsusceptible organisms, including Candida and Clostridium difficile., Caution in patients with history of gastrointestinal disease, particularly colitis. |
| Food/Dietary | Food decreases the absorption of cephradine; take on an empty stomach. Avoid alcohol-containing products during therapy and for 72 hours after completion due to risk of disulfiram-like reaction (though rare with cephalosporins). |
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| Teratogenic Risk | Cefradine (Velosef) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate human studies in pregnant women exist. First trimester: No evidence of teratogenicity; however, use only if clearly needed. Second and third trimesters: Generally considered safe; no known fetal adverse effects. Potential for alteration of gut flora in neonate if administered near term. |
| Fetal Monitoring | No specific monitoring required beyond routine prenatal care. In prolonged use, monitor maternal renal function and complete blood count (CBC) due to potential for neutropenia. Fetal monitoring: No specific indications, but standard fetal surveillance if maternal infection severe. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies show no impairment of fertility. |
| Clinical Pearls | Velosef '500' (cephradine) is a first-generation cephalosporin with activity against Gram-positive cocci (except enterococci) and some Gram-negative organisms. It is acid-stable and well-absorbed orally. Administer on an empty stomach for optimal absorption. Use with caution in penicillin-allergic patients due to cross-sensitivity (5-10%). Monitor renal function in elderly or renally impaired patients; adjust dose as needed. Not effective against MRSA or anaerobes. |
| Patient Advice | Take this medication exactly as prescribed, usually 4 times daily. · Take on an empty stomach (1 hour before or 2 hours after meals) for best absorption. · Complete the full course of therapy even if you feel better to prevent resistance. · If you miss a dose, take it as soon as possible; if near the next dose, skip the missed dose and resume regular schedule; do not double dose. · Report any signs of allergic reaction (rash, hives, difficulty breathing) or severe diarrhea. · Do not use this medication if you have a history of severe allergic reaction to cephalosporins or penicillins. |