Meropenem Dosing in Adults with Impaired Renal Function
For adults with impaired renal function, meropenem dosage should be reduced based on creatinine clearance: 500 mg-1 g every 12 hours for CrCl 26-50 mL/min, half the recommended dose every 12 hours for CrCl 10-25 mL/min, and half the recommended dose every 24 hours for CrCl <10 mL/min. 1
Dosing Algorithm Based on Renal Function
The FDA-approved meropenem dosing adjustments for adults with renal impairment are as follows:
| Creatinine Clearance (mL/min) | Dose | Dosing Interval |
|---|---|---|
| >50 mL/min | Recommended dose (500 mg for cSSSI and 1 gram for intra-abdominal infections) | Every 8 hours |
| 26-50 mL/min | Recommended dose | Every 12 hours |
| 10-25 mL/min | One-half recommended dose | Every 12 hours |
| <10 mL/min | One-half recommended dose | Every 24 hours |
Special Considerations for Specific Infections
For different types of infections, the base dosing (before renal adjustment) varies:
- Complicated skin and skin structure infections: 500 mg every 8 hours
- Complicated intra-abdominal infections: 1 gram every 8 hours
- For infections caused by Pseudomonas aeruginosa: 1 gram every 8 hours 1
When treating severe infections such as meningitis or those caused by resistant organisms:
- For bacterial meningitis (in the UK guidelines): 2 g IV every 8 hours 2
- For ESBL-producing organisms: 2 g IV every 8 hours 2
Administration Methods
Meropenem can be administered in several ways:
- Intravenous infusion over 15-30 minutes (standard)
- Intravenous bolus injection over 3-5 minutes
- Extended infusion over 3 hours (recommended for severe infections or high MICs) 3
Patients on Renal Replacement Therapy
For patients on continuous renal replacement therapy (CRRT):
- Pharmacokinetic studies show that CRRT contributes significantly to meropenem elimination
- For patients on continuous venovenous hemofiltration (CVVH), the dose should be increased by approximately 100% compared to anuric patients not on CRRT 4
- Residual diuresis (remaining urine output) is an important factor affecting clearance in patients on CRRT 5
Clinical Pearls and Pitfalls
Calculate creatinine clearance accurately: When only serum creatinine is available, use the Cockcroft-Gault equation:
- Males: CrCl (mL/min) = Weight (kg) × (140 - age) / (72 × serum creatinine [mg/dL])
- Females: CrCl (mL/min) = 0.85 × male value 1
Monitoring considerations:
- Regular monitoring of renal function is essential during therapy
- For prolonged therapy, monitor for superinfection and emergence of resistance
Safety profile:
- Meropenem is generally well-tolerated even in patients with renal impairment when properly dosed
- The most common adverse events include diarrhea, nausea, vomiting, headache, rash, and injection site inflammation 6
- Unlike imipenem, meropenem has a lower risk of seizures and does not require co-administration with cilastatin 7
Extended infusion consideration:
- For severe infections or when targeting organisms with higher MICs, consider extended infusion (3 hours) to optimize the time above MIC
- This approach may be particularly beneficial in critically ill patients 3
Avoid underdosing in CRRT:
- Patients on CRRT may require higher doses than those with similar degrees of renal impairment not on CRRT 4
By following these evidence-based dosing recommendations, clinicians can optimize meropenem therapy in patients with impaired renal function, balancing efficacy against the risk of toxicity.