Renal Dose Adjustment for Cefixime
For patients with creatinine clearance ≥60 mL/min, use the standard dose of 400 mg daily; for creatinine clearance 21-59 mL/min, reduce to 300 mg daily (or 13 mL of 200 mg/5 mL suspension); for creatinine clearance ≤20 mL/min or patients on dialysis, reduce to 200 mg daily (or 8.6 mL of 100 mg/5 mL suspension). 1
Dosing Algorithm by Renal Function
The FDA-approved dosing adjustments for cefixime are straightforward and based on creatinine clearance thresholds:
Normal to Mild Renal Impairment (CrCl ≥60 mL/min)
- Standard adult dose: 400 mg once daily
- No adjustment needed
- Can be given as capsule or suspension 1
Moderate Renal Impairment (CrCl 21-59 mL/min)
- Reduced dose: 300 mg once daily
- Suspension formulation: 13 mL of 200 mg/5 mL concentration OR 6.5 mL of 200 mg/5 mL concentration
- This represents approximately 75% of the standard dose 1
Severe Renal Impairment (CrCl ≤20 mL/min)
- Reduced dose: 200 mg once daily
- Suspension formulation: 8.6 mL of 100 mg/5 mL concentration OR 4.4 mL of 200 mg/5 mL concentration
- This represents 50% of the standard dose 1
Dialysis Patients
- Same as severe renal impairment: 200 mg once daily
- Neither hemodialysis nor peritoneal dialysis removes significant amounts of cefixime from the body
- No supplemental dose needed after dialysis 1, 2
Pharmacokinetic Rationale
The dose adjustments are based on well-established pharmacokinetic changes in renal impairment. Research demonstrates that cefixime elimination half-life increases from approximately 3.7 hours in normal renal function to 12-14 hours when creatinine clearance falls below 20 mL/min 3. The apparent total body clearance and renal clearance decrease proportionally with declining renal function 3, 2.
Important consideration: Despite reduced clearance, urinary concentrations of cefixime remain above the MIC for most urinary tract pathogens for up to 24 hours post-dose, even in severe renal insufficiency 2. This supports the once-daily dosing strategy rather than extending intervals.
Clinical Pitfalls to Avoid
Do not use standard doses in severe renal impairment: Patients with CrCl <20 mL/min receiving 400 mg daily will experience significantly elevated drug concentrations and prolonged half-life, increasing toxicity risk 3, 4
Avoid unnecessary post-dialysis supplementation: Unlike many renally-cleared antibiotics, cefixime is NOT significantly removed by hemodialysis or peritoneal dialysis (only 1.57% removed over 72 hours with CAPD) 2
Preferred concentration matters: For patients with renal dysfunction requiring liquid formulation, the FDA label specifically recommends using the 200 mg/5 mL concentration for easier measurement of reduced doses 1
Timing flexibility: Cefixime can be administered without regard to meals, which simplifies dosing in patients with complex medication schedules 1
Special Populations
Elderly patients: Many elderly patients have reduced creatinine clearance despite "normal" serum creatinine due to decreased muscle mass. Calculate actual creatinine clearance rather than relying on serum creatinine alone to determine appropriate dosing 2.
Cirrhotic patients: No dose adjustment is required in hepatic impairment, though elimination half-life may increase to approximately 6.5 hours 4.