Meropenem Dosing for UTI with GFR 21 mL/min
For a patient with GFR 21 mL/min and a UTI, administer meropenem 500 mg intravenously every 12 hours as a 30-minute infusion. 1
Dosing Algorithm Based on FDA Label
The FDA-approved dosing for meropenem in renal impairment follows a clear creatinine clearance-based algorithm 1:
- GFR 10-25 mL/min: Administer one-half the recommended dose every 12 hours 1
- Since the standard dose for UTI/complicated intra-abdominal infections is 1 gram every 8 hours, the adjusted dose becomes 500 mg every 12 hours 1
This patient with GFR 21 mL/min falls squarely into the 10-25 mL/min category, making the dose adjustment straightforward 1.
Administration Method
- Administer as an intravenous infusion over 15-30 minutes 1
- Alternatively, may give as an intravenous bolus over 3-5 minutes, though infusion is preferred for renal impairment 1
Pharmacokinetic Rationale
The dose reduction is necessary because 2, 3:
- Meropenem is 63% renally excreted unchanged 4
- In patients with acute renal failure, the elimination half-life extends to 8.7 hours (compared to ~1 hour in normal renal function) 2
- Total clearance drops to approximately 52 mL/min in anuric patients 2
- The non-renal clearance remains at approximately 30 mL/min regardless of kidney function 2
Critical Considerations for UTI Treatment
If treating Pseudomonas aeruginosa, consider the following modifications 5:
- The standard dose for P. aeruginosa UTI is 1 gram every 8 hours in normal renal function 1
- With GFR 21 mL/min, this becomes 500 mg every 12 hours (one-half dose, extended interval) 1
- Clinical efficacy of meropenem for complicated UTI with resistant organisms has been demonstrated at 1 gram every 12 hours in patients with creatinine clearance below 50 mL/min 5
Common Pitfalls to Avoid
Do not reduce the dosing interval further 1:
- The FDA label specifically recommends every 12-hour dosing for GFR 10-25 mL/min, not every 8 hours 1
- Shorter intervals risk drug accumulation and potential neurotoxicity 6
Avoid premature dose escalation 6:
- Neurological toxicity occurs when trough concentrations exceed 64 mg/L 6
- The half-dose, extended-interval approach prevents excessive accumulation 1
Monitor for clinical response rather than arbitrary duration 5:
- Treatment courses of 7-10 days achieved 88.9% bacteriological efficacy in complicated UTI with severe renal impairment 5
Special Circumstances
If the patient is on hemodialysis or peritoneal dialysis 1:
- The FDA label states there is inadequate information for specific dosing recommendations 1
- However, approximately 50% of meropenem is removed by intermittent hemodialysis, so doses should be administered after dialysis sessions 6
If considering continuous renal replacement therapy (CRRT) 2, 3:
- CRRT removes 25-50% of meropenem 6
- Recommended dose is 1 gram every 8-12 hours to compensate for continuous removal 6
- This is NOT applicable to your patient with GFR 21 who is not on dialysis 1
Monitoring Parameters
Track the following throughout treatment 6: