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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MEFOXIN IN PLASTIC CONTAINER (MEFOXIN IN PLASTIC CONTAINER).
| Breastfeeding | Cefoxitin is excreted in human breast milk in low concentrations (M/P ratio not established). It is considered compatible with breastfeeding; however, caution is advised due to potential alteration of infant gut flora. |
| 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. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to cefoxitin or other cephalosporins","Severe immediate hypersensitivity reactions to penicillins (cross-sensitivity)"]
| 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"] |
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| 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. |