MEFOXIN IN PLASTIC CONTAINER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MEFOXIN IN PLASTIC CONTAINER (MEFOXIN IN PLASTIC CONTAINER).
Cefoxitin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), thereby inhibiting peptidoglycan cross-linking. It is resistant to beta-lactamases produced by Gram-negative and Gram-positive bacteria.
| Metabolism | Cefoxitin is not significantly metabolized; it is primarily excreted unchanged in urine via glomerular filtration and tubular secretion. |
| Excretion | Primarily renal; 85% of a dose excreted unchanged in urine within 6 hours via glomerular filtration and tubular secretion. Biliary excretion accounts for <2%; fecal elimination minimal. |
| Half-life | 0.7–1.2 hours in adults with normal renal function; prolonged to >20 hours in severe renal impairment (CrCl <10 mL/min), requiring dose adjustment. |
| Protein binding | 65–80% bound to serum albumin. |
| Volume of Distribution | 0.13–0.16 L/kg, approximating extracellular fluid volume; low distribution into CSF unless meninges inflamed. |
| Bioavailability | IM: ~95–100%. |
| Onset of Action | IM administration: therapeutic levels in 30–60 minutes; IV administration: immediate. |
| Duration of Action | 6–8 hours for bacterial killing; requires frequent dosing (q6-8h) due to short half-life. |
| Molecular Weight | 427.45 Da |
1-2 g IV every 6-8 hours (adults).
| 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: 1-2 g every 24-48 hours. |
| Liver impairment | No specific dose adjustment for Child-Pugh classification recommended; use with caution in severe hepatic impairment. |
| Pediatric use | 80-160 mg/kg/day IV divided every 6-8 hours (max 12 g/day). |
| Geriatric use | Consider age-related renal impairment; adjust dose based on creatinine clearance. |
| 1st trimester | Cefoxitin crosses the placenta and achieves fetal serum levels. Animal studies have not revealed evidence of teratogenicity, but adequate and well-controlled studies in pregnant women are lacking. Use only if clearly needed. |
| 2nd trimester | Adequate studies in pregnant women are lacking. Use only if clearly needed. |
| 3rd trimester | Cefoxitin is excreted in small amounts in breast milk and is generally considered compatible with breastfeeding. |
Clinical note
Comprehensive clinical and safety monograph for MEFOXIN IN PLASTIC CONTAINER (MEFOXIN IN PLASTIC CONTAINER).
| Placental transfer | Yes, cefoxitin crosses the placenta and achieves significant fetal serum concentrations. |
| Breastfeeding | Cefoxitin is excreted in breast milk in low concentrations. Although it is generally considered compatible with breastfeeding, caution is advised as it may alter infant gut flora and interfere with culture results if fever workup is needed. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to cefoxitin or other cephalosporinsHistory of immediate-type hypersensitivity reaction (e.g., anaphylaxis) to penicillins
| Precautions | Hypersensitivity reactions including anaphylaxis and Stevens-Johnson syndrome, Clostridium difficile-associated diarrhea (CDAD), Seizures in patients with renal impairment or high doses, Reduction in dose required in renal impairment (creatinine clearance <50 mL/min), Prolonged use may result in superinfection with non-susceptible organisms, Use caution in patients with a history of gastrointestinal disease, especially colitis, May cause false-positive urine glucose tests (Clinitest) and direct Coombs test |
| Food/Dietary | No specific food interactions. Alcohol may increase the risk of disulfiram-like reaction with some cephalosporins, but cefoxitin does not contain a methylthiotetrazole side chain and such interaction is not reported. However, consumption of alcohol is not recommended during therapy. |
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| Lactation Rating | L2 |
| Teratogenic Risk | Cefoxitin is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate and well-controlled studies in pregnant women. Trimesters: No known teratogenic effects; use only if clearly needed. |
| Fetal Monitoring | Monitor maternal renal function and signs of hypersensitivity. For prolonged therapy, monitor for superinfection and bleeding time (vitamin K synthesis). Fetal monitoring as clinically indicated. |
| Fertility Effects | No known adverse effects on fertility. Animal studies have not shown impaired fertility at clinically relevant doses. |
| Clinical Pearls | Cefoxitin has activity against Bacteroides fragilis, making it useful for mixed aerobic-anaerobic infections such as intra-abdominal and pelvic infections. It is not active against Pseudomonas aeruginosa or Enterococci. Dose adjustment required in renal impairment (CrCl <50 mL/min). Administer by deep IM injection or IV over 3-5 minutes. Contains sodium; caution in heart failure. IV piggyback with minibag compatible with most common IV fluids. Avoid mixing with aminoglycosides in the same IV line. |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. · Complete the full course of therapy to prevent bacterial resistance. · Inform your healthcare provider if you have any drug allergies, especially to penicillin or cephalosporins. · Report any signs of allergic reaction, such as rash, itching, or difficulty breathing. · This medication may cause diarrhea; contact your doctor if it becomes severe or bloody. · If you have kidney disease, your dose may need adjustment. · Store the premixed frozen solution in the freezer and thaw before use; do not refreeze. · Do not use the container if the solution is cloudy or contains particles. |