Meropenem Dosing Guidelines for Adults
The standard dose of meropenem for adults with normal renal function is 1 gram intravenously every 8 hours for intra-abdominal infections, with dosage adjustments required for patients with renal impairment. 1
Standard Adult Dosing (Normal Renal Function)
- Skin and skin structure infections: 500 mg IV every 8 hours
- Intra-abdominal infections: 1 gram IV every 8 hours
- Complicated skin and skin structure infections caused by P. aeruginosa: 1 gram IV every 8 hours
- Administration method:
- Intravenous infusion over 15-30 minutes, or
- Intravenous bolus injection over 3-5 minutes (for 1 gram doses)
Dosing in Renal Impairment
Dosage must be adjusted based on creatinine clearance (CrCl) 1:
| Creatinine Clearance (mL/min) | Dose | Dosing Interval |
|---|---|---|
| >50 | Recommended dose | Every 8 hours |
| 26-50 | Recommended dose | Every 12 hours |
| 10-25 | One-half recommended dose | Every 12 hours |
| <10 | One-half recommended dose | Every 24 hours |
To estimate creatinine clearance when only serum creatinine is available (Cockcroft-Gault equation) 1:
- Males: CrCl (mL/min) = Weight (kg) × (140 - age) / (72 × serum creatinine [mg/dL])
- Females: CrCl (mL/min) = 0.85 × above value
Special Considerations
Renal Replacement Therapy
- The half-life of meropenem (normally ~1 hour) can be prolonged up to 13.7 hours in anuric patients with end-stage renal disease 2
- Approximately 50% of meropenem is eliminated by intermittent hemodialysis, 25-50% by continuous venovenous hemofiltration, and 13-53% by continuous venovenous hemodiafiltration 2
- Specific dosing recommendations for patients on dialysis should be determined based on the type of renal replacement therapy
Elderly Patients
- Meropenem has an excellent safety profile in elderly patients (>65 years) 3
- Dose adjustment should be based on renal function rather than age alone
- No increased risk of adverse events has been observed in elderly patients compared to younger patients
Pharmacodynamic Considerations
- Meropenem exhibits time-dependent killing with a post-antibiotic effect against gram-negative bacilli 4
- For optimal efficacy, serum concentrations should remain above the MIC of the infecting organism for as long as possible
- For serious infections, higher doses or more frequent administration may be required to maintain adequate drug levels
Common Pitfalls and Caveats
Underdosing in renal replacement therapy: Different modalities of renal replacement therapy have varying effects on meropenem clearance. Clinicians should avoid underdosing due to concerns about toxicity, as meropenem has an excellent tolerability profile 2.
CNS infections: While not specifically addressed in the question, it's worth noting that meropenem has good CNS penetration and is used for meningitis at higher doses (2g every 8 hours in adults).
Monitoring: Unlike vancomycin or aminoglycosides, routine therapeutic drug monitoring is not required for meropenem.
Administration timing: For optimal efficacy, administration should be consistent with scheduled intervals to maintain adequate serum concentrations.
Meropenem is generally well-tolerated with minimal adverse effects, making it suitable for use in various patient populations, including those with renal impairment when appropriately dosed 3.