CEFOXITIN IN PLASTIC CONTAINER
Clinical safety rating: safe
Probenecid may decrease cephalosporin excretion May cause diarrhea including Clostridium difficile-associated diarrhea.
Cefoxitin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), specifically PBP1a, PBP1b, and PBP2, thereby inhibiting transpeptidation and leading to cell lysis. It is a cephamycin antibiotic resistant to beta-lactamase hydrolysis due to a 7-alpha-methoxy group.
| Metabolism | Cefoxitin is metabolized primarily in the liver via enzymatic hydrolysis of the beta-lactam ring to an inactive metabolite; it is not significantly metabolized by cytochrome P450 enzymes. |
| Excretion | Renal: 85-95% unchanged via glomerular filtration and tubular secretion; biliary: <2%; fecal: trace. |
| Half-life | Terminal elimination half-life: 0.7-1.5 hours (approximately 45-90 minutes); prolonged to 2-6 hours in moderate renal impairment (CrCl 30-50 mL/min) and up to 10-20 hours in severe renal impairment (CrCl <10 mL/min). |
| Protein binding | Approximately 50-75% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 0.2-0.3 L/kg, indicating distribution primarily into extracellular fluid and minimal intracellular penetration. |
| Bioavailability | IM: approximately 100% (complete absorption); IV: 100%. |
| Onset of Action | IV administration: immediate; IM administration: within 30-60 minutes. |
| Duration of Action | Approximately 4-6 hours following IV administration; prolonged in renal impairment. Clinical notes: Dosing interval is typically 6-8 hours in normal renal function, adjusted in renal impairment. |
1-2 g IV every 6-8 hours; maximum 12 g/day
| Dosage form | POWDER |
| Renal impairment | CrCl 30-50 mL/min: 1-2 g q8h; CrCl 10-29 mL/min: 1-2 g q12h; CrCl <10 mL/min: 1-2 g q24-48h; hemodialysis: 1-2 g post-dialysis |
| Liver impairment | No dose adjustment required for hepatic impairment; monitor for adverse effects |
| Pediatric use | Neonates <1 week: 40 mg/kg/dose IV q12h; Infants 1-4 weeks: 40 mg/kg/dose IV q8h; Children ≥1 month: 80-160 mg/kg/day IV divided q6-8h (max 12 g/day); for severe infections: up to 200-240 mg/kg/day IV divided q4-6h |
| Geriatric use | Adjust dose based on renal function; consider lower initial dose (1 g q8h) due to age-related decreased renal clearance; monitor for superinfection and bleeding risk |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Probenecid may decrease cephalosporin excretion May cause diarrhea including Clostridium difficile-associated diarrhea.
| FDA category | Human |
| Breastfeeding | Cefoxitin is excreted in human milk in low concentrations. The milk-to-plasma (M/P) ratio is approximately 0.1. It is considered compatible with breastfeeding; however, caution should be exercised due to potential alteration of infant gut flora and rare hypersensitivity reactions. |
| Teratogenic Risk |
■ FDA Black Box Warning
None
| Common Effects | Diarrhea |
| Serious Effects |
["Hypersensitivity to cefoxitin or any other cephalosporin antibiotic","Anaphylactic reaction to penicillins (relative contraindication due to cross-sensitivity)"]
| Precautions | ["Serious hypersensitivity reactions (anaphylaxis) may occur, especially in patients with penicillin allergy (cross-allergenicity ~10%)","Clostridioides difficile-associated diarrhea (CDAD) ranging from mild to fatal","Hemolytic anemia (immune-mediated) has been reported; monitor hematologic parameters","Dose adjustment required in renal impairment (CrCl <30 mL/min); monitor renal function","May increase INR in patients on warfarin due to effect on gut flora VK synthesis","Pseudomembranous colitis risk; discontinue if diarrhea occurs","Mitigation of drug-resistant bacteria: use only when indicated"] |
| Food/Dietary |
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| Cefoxitin is a beta-lactam antibiotic classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated fetal risk, and there are no adequate and well-controlled studies in pregnant women. Potential fetal risks are low; however, use during pregnancy only if clearly needed. No specific teratogenic effects have been reported in any trimester. |
| Fetal Monitoring | Monitor maternal renal function, as cefoxitin is primarily excreted renally. No specific fetal monitoring required; standard obstetric monitoring is recommended. |
| Fertility Effects | No studies have been conducted on fertility effects in humans. Animal studies have not shown impaired fertility at clinically relevant doses. |
| No significant food interactions. However, alcohol should be avoided as cefoxitin may cause a disulfiram-like reaction (nausea, vomiting, flushing, headache). |
| Clinical Pearls | Cefoxitin is a cephamycin antibiotic effective against anaerobic bacteria, including Bacteroides fragilis. It is often used for surgical prophylaxis, particularly in colorectal surgery. Monitor renal function due to potential nephrotoxicity. Reconstitute with sterile water, not lactated Ringer's, as calcium-containing solutions may cause precipitation. Administer via intermittent IV infusion over 30-60 minutes. Cefoxitin can cause false-positive urine glucose tests; use glucose oxidase methods. |
| Patient Advice | Complete the full course even if you feel better. · Report any signs of allergic reactions (rash, itching, swelling, difficulty breathing) immediately. · May cause diarrhea; contact your doctor if severe or bloody. · Inform your doctor if you have kidney disease or a history of colitis. · Use effective contraception during treatment if applicable. |