Cefoxitin Dosing in Hemodialysis Patients
For patients with CKD on hemodialysis, administer cefoxitin 1-2 grams as a loading dose after each hemodialysis session, followed by maintenance doses of 1-2 grams every 24-48 hours depending on infection severity, given after dialysis. 1, 2
Loading Dose Strategy
- Administer a loading dose of 1-2 grams immediately after hemodialysis to achieve therapeutic levels, as hemodialysis significantly increases cefoxitin clearance (approximately fivefold) and removes substantial amounts of the drug 2
- The loading dose is critical because cefoxitin is extensively dialyzed, with serum half-life decreasing from 23.5 hours in anuric patients to approximately 3-4 hours during active hemodialysis 2, 3
Maintenance Dosing
- After the loading dose, give 1-2 grams every 24-48 hours based on infection severity, with timing coordinated to occur after dialysis sessions 1, 2
- For severe infections requiring higher doses, use 2 grams; for moderate infections, 1 gram is appropriate 1
- The extended dosing interval (24-48 hours) is necessary because cefoxitin accumulates significantly in hemodialysis patients, with serum concentrations remaining therapeutic (>16 mcg/mL) for 24 hours post-dose 4
Critical Timing Considerations
- Always administer supplemental doses after hemodialysis, not before, as dialysis removes 10-20% of the administered dose and dramatically shortens the elimination half-life 2, 4
- In patients with end-stage renal disease not actively on dialysis, the cefoxitin half-life extends to 23.5 hours compared to 39 minutes in normal renal function, necessitating less frequent dosing 3
Important Caveats
- This pharmacy bulk package formulation should only be used in patients requiring exactly 1 gram doses—it cannot be used for fractional doses or patients requiring less than 1 gram 1
- Hemodialysis increases cefoxitin clearance approximately fivefold, but even with this enhancement, substantial drug accumulation occurs between dialysis sessions 2
- Monitor for signs of drug accumulation, particularly in patients with residual renal function or those on less frequent dialysis schedules 3
Pharmacokinetic Rationale
- Cefoxitin is predominantly eliminated renally (>60% in patients with creatinine clearance >30 mL/min), making dose adjustment essential in renal failure 2
- The elimination rate constant correlates best with p-aminohippurate clearance, indicating active tubular secretion as the primary elimination mechanism, though creatinine clearance provides adequate guidance for dosing adjustments 3
- Total body clearance decreases from 340 mL/min in normal function to 13 mL/min per 1.73 m² in oligoanuric patients 3