What is the recommended dosage of Cefoxitin for a general adult patient with a bacterial infection and potentially impaired renal function or hepatic dysfunction?

Cefoxitin Dosage for Adult Patients

For general adult patients with bacterial infections and normal renal function, administer cefoxitin 1-2 grams intravenously every 6-8 hours, with doses adjusted based on infection severity (up to 12 grams daily for severe infections like gas gangrene), and reduce dosing or extend intervals in patients with renal impairment according to creatinine clearance. 1, 2

Standard Adult Dosing by Infection Severity

The dosing algorithm follows infection severity:

• Uncomplicated infections (pneumonia, urinary tract infection, cutaneous infection): 1 gram IV every 6-8 hours (total 3-4 grams daily) 1, 2

• Moderately severe or severe infections: 1 gram IV every 4 hours OR 2 grams every 6-8 hours (total 6-8 grams daily) 1, 2

• Severe infections requiring higher doses (gas gangrene, complicated intra-abdominal infections): 2 grams every 4 hours OR 3 grams every 6 hours (maximum 12 grams daily) 1, 2

The standard recommendation from the Surgical Infection Society and IDSA for complicated intra-abdominal infections specifically lists cefoxitin at 2 grams every 6 hours. 1

Renal Impairment Dosing Adjustments

Critical consideration: Cefoxitin requires mandatory dose adjustment in renal dysfunction to prevent nephrotoxicity and seizures. 3, 4

Adjust dosing based on creatinine clearance (CrCl):

• Mild impairment (CrCl 30-50 mL/min): 1-2 grams every 8-12 hours 2

• Moderate impairment (CrCl 10-29 mL/min): 1-2 grams every 12-24 hours 2

• Severe impairment (CrCl 5-9 mL/min): 0.5-1 gram every 12-24 hours 2

• Essentially no function (CrCl <5 mL/min): 0.5-1 gram every 24-48 hours 2

Hepatic Dysfunction Considerations

No specific dose adjustment is required for hepatic dysfunction alone, as cefoxitin is primarily renally eliminated (75% excreted unchanged in urine within 24 hours). 3 However, monitor liver function tests intermittently throughout treatment as part of routine toxicity monitoring. 3, 4

Administration Guidelines

• Reconstitution: Doses must be reconstituted with Sterile Water for Injection 3

• Infusion requirements: Doses over 2 grams require dilution in sodium chloride 0.9% or glucose 5% and administration by IV infusion over 30-60 minutes 3, 4

• Smaller doses: Can be given as IV bolus or infusion 3

Critical Monitoring Requirements

Monitor these parameters closely to prevent serious adverse effects:

• Renal function (serum creatinine, creatinine clearance): Check baseline and intermittently throughout treatment, especially when combining with aminoglycosides or furosemide due to increased nephrotoxicity risk 3, 4

• Complete blood count: Monitor for eosinophilia, leukopenia, and thrombocytopenia 3, 4

• Liver function tests: Perform intermittently during treatment 3, 4

Important caveat: Cefoxitin interferes with Jaffé method creatinine assays, producing falsely elevated creatinine values—use enzymatic creatinine assays when available to avoid inappropriate dose reductions. 4

Drug Interactions Requiring Dose Modification

• Probenecid: Reduces renal excretion of cefoxitin, resulting in increased and prolonged serum levels—consider reducing cefoxitin dose or avoiding combination 3, 4

• Warfarin: Monitor INR closely as cefoxitin increases anticoagulant effect 3

Common Pitfalls to Avoid

1. Do not use standard dosing in renal impairment without adjustment—this significantly increases seizure and nephrotoxicity risk 4

2. Do not rely on serum creatinine alone if measured by Jaffé method, as cefoxitin causes false elevation 4

3. Do not administer doses >2 grams as IV bolus—must be given as infusion to prevent thrombophlebitis 3, 4

4. Watch for thrombophlebitis at injection sites, the most common adverse effect 3