CEFOXITIN
Clinical safety rating: safe
Human studies have proved safety
Cefoxitin is a cephamycin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), particularly PBP-1 and PBP-3, thereby inhibiting the final transpeptidation step of peptidoglycan synthesis. This leads to cell lysis and death. It is resistant to beta-lactamases produced by many Gram-negative and Gram-positive bacteria.
| Metabolism | Cefoxitin is not significantly metabolized hepatically; it undergoes minimal hepatic metabolism and is primarily eliminated unchanged by the kidneys via glomerular filtration and tubular secretion. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 85% of elimination; biliary excretion is minimal (<1%); fecal elimination is negligible. |
| Half-life | Terminal elimination half-life is approximately 0.7–1.1 hours (mean 0.8 h) in adults with normal renal function, extending to 5–10 hours in severe renal impairment (CrCl <10 mL/min). |
| Protein binding | Protein binding is approximately 50–75%, primarily to albumin. |
| Volume of Distribution | Volume of distribution is 0.13–0.26 L/kg (mean 0.17 L/kg), indicating distribution primarily into extracellular fluid. |
| Bioavailability | IM administration: bioavailability is approximately 100% (complete absorption); oral: not available (only parenteral). |
| Onset of Action | IV administration: onset within minutes; IM administration: onset within 15–30 minutes. |
| Duration of Action | Duration of action is approximately 4–6 hours after IV or IM administration, correlating with serum concentrations above MIC for susceptible organisms. |
| Action Class | Cephalosporins: 4th generation |
| Brand Substitutes | Cefpy 1000mg Injection, Winpime 1000mg Injection, Corpime 1000mg Injection, Chase 1000mg Injection, Kefage 1000mg Injection, Lyfipime SB Injection, Pimedose SB 1000mg/500mg Injection, Befsul 1.5gm Injection, Zardpime S Injection, Inpime 1000mg/500mg Injection |
1-2 g IV every 6-8 hours; maximum 12 g/day.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 30-50 mL/min: 1-2 g every 8-12 hours; CrCl 10-29 mL/min: 1-2 g every 12-24 hours; CrCl <10 mL/min: 0.5-1 g every 12-24 hours; hemodialysis: 1-2 g after dialysis. |
| Liver impairment | No adjustment required for mild-to-moderate hepatic impairment; insufficient data for severe impairment. |
| Pediatric use | Infants >3 months and children: 80-160 mg/kg/day IV divided every 4-6 hours; maximum 12 g/day. |
| Geriatric use | Start at lower end of dosing range; adjust based on renal function (CrCl often decreased in elderly); maximum 12 g/day. |
| 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.
| Breastfeeding | Cefoxitin is excreted into human breast milk in low concentrations. The milk-to-plasma ratio is approximately 0.04. The American Academy of Pediatrics considers it compatible with breastfeeding. However, caution should be exercised due to potential alteration of infant gut flora and possible interference with culture results. |
| Teratogenic Risk | Cefoxitin is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and there are no adequate well-controlled studies in pregnant women. The drug should be used during pregnancy only if clearly needed. No teratogenic effects have been reported in the first trimester; potential risks in second and third trimesters are considered low. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to cefoxitin or any component of the formulation","History of anaphylactic reaction to penicillins or other cephalosporins","Porphyria (relative contraindication)"]
| Precautions | ["Hypersensitivity reactions (e.g., anaphylaxis, rash, urticaria); cross-allergenicity with penicillins and other beta-lactams","Clostridioides difficile-associated diarrhea (CDAD): Consider in patients presenting with diarrhea after antibiotic use","Seizures, encephalopathy, or other neurological adverse events, especially in patients with renal impairment or those receiving high doses","Hemolytic anemia, including positive direct Coombs test (rare)","Renal function monitoring: Dosage adjustment required in patients with moderate to severe renal impairment (creatinine clearance <50 mL/min)","Prolonged use may result in superinfection with non-susceptible organisms","Coagulation abnormalities (e.g., hypoprothrombinemia) reported, particularly in elderly or malnourished patients"] |
| Food/Dietary | Avoid alcohol and alcohol-containing products during therapy and for 48 hours after completion due to risk of disulfiram-like reaction. No significant food interactions. |
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| Fetal Monitoring | Monitor maternal renal function and complete blood count during prolonged therapy. For neonates exposed in utero, observe for signs of hypersensitivity reactions and gastrointestinal disturbances. No specific fetal monitoring is routinely required; however, assess for potential allergic reactions in the mother. |
| Fertility Effects | No significant adverse effects on fertility have been reported in animal studies. There is no evidence that cefoxitin impairs reproductive capacity in humans. |
| Clinical Pearls | Cefoxitin is a cephamycin antibiotic active against anaerobes (including Bacteroides fragilis) and used for intra-abdominal and pelvic infections, diabetic foot infections, and surgical prophylaxis. It has poor activity against Pseudomonas and Enterococcus. Dose adjustment required in renal impairment (CrCl <50 mL/min). Administer by IV or IM; deep IM injection preferred to avoid pain. Do not use in patients with cephalosporin allergy; cross-allergy with penicillins possible. |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. · Complete the full course of treatment to prevent resistance. · Common side effects include diarrhea, nausea, and pain at injection site. · Report severe diarrhea, rash, or difficulty breathing immediately. · Avoid alcohol during treatment and for 48 hours after last dose to prevent disulfiram-like reaction. · This drug may cause false-positive urine glucose tests; use glucose-specific methods. · Inform your doctor if you are pregnant, breastfeeding, or have kidney disease. |