Meropenem Dosing in Adults
Standard Dosing for Normal Renal Function
For adults with normal renal function, meropenem should be dosed at 1 gram intravenously every 8 hours for most serious infections, including intra-abdominal infections, hospital-acquired pneumonia, and carbapenem-resistant infections. 1
- For complicated skin and skin structure infections (cSSSI) not involving Pseudomonas aeruginosa, a reduced dose of 500 mg every 8 hours may be used 1
- When P. aeruginosa is suspected or confirmed in skin infections, increase to 1 gram every 8 hours 1
- Extended infusion over 3 hours is recommended when treating resistant organisms with MIC ≥8 mg/L to optimize time above MIC 2, 3
- Standard infusion duration is 15-30 minutes for most infections 1
- Bolus injection over 3-5 minutes is an alternative administration method 1
Critical Considerations for ICU Patients
- Critically ill patients with preserved renal function often require higher doses due to increased drug clearance and altered volume of distribution 3
- Therapeutic drug monitoring should be considered in ICU patients with expected pharmacokinetic variability or clinical signs of toxicity 3
- Neurological toxicity typically occurs when trough concentrations exceed 64 mg/L 2, 3
Dosing Adjustments for Renal Impairment
Dose adjustments are mandatory in renal impairment based on creatinine clearance, with the key principle being to maintain the full gram dose while extending the dosing interval rather than reducing individual doses. 1
Renal Dosing Algorithm
| Creatinine Clearance | Dose | Interval |
|---|---|---|
| >50 mL/min | Full dose (500 mg or 1 g) | Every 8 hours |
| 26-50 mL/min | Full dose (500 mg or 1 g) | Every 12 hours |
| 10-25 mL/min | Half dose (250 mg or 500 mg) | Every 12 hours |
| <10 mL/min | Half dose (250 mg or 500 mg) | Every 24 hours |
Key Principles for Renal Dosing
- Maintain the full 1 gram dose and extend the interval to every 12 hours for moderate impairment (CrCl 26-50 mL/min) to preserve peak concentrations needed for concentration-dependent killing 2
- The elimination half-life increases from approximately 1 hour in healthy volunteers to up to 13.7 hours in anuric patients 4, 5
- Approximately 70% of meropenem is excreted unchanged in urine, making renal function the primary determinant of clearance 5
Special Populations: Renal Replacement Therapy
Intermittent Hemodialysis (IHD)
- Administer meropenem after dialysis sessions to prevent premature drug removal 2
- Approximately 50% of meropenem is removed during a single hemodialysis session 2, 4
- Recommended dosing: 500 mg after each dialysis session for standard infections 2
Continuous Renal Replacement Therapy (CRRT)
For patients on CRRT, use 1 gram every 8-12 hours to compensate for continuous drug removal. 2
- CVVH removes 25-50% of meropenem 2, 4
- CVVHDF removes 13-53% of meropenem 2, 4
- The sieving coefficient is approximately 0.93, indicating free flow across the filter 6
- Elimination half-life during CRRT is approximately 2.5-8.7 hours 2
- Therapeutic drug monitoring is strongly recommended for all patients on CRRT to ensure adequate exposure 2, 3
Sustained Low-Efficiency Dialysis (SLED)
- Maintain the full 1 gram dose every 12 hours 2
- Do not reduce individual doses below 1 gram, as this may compromise efficacy 2
Critical Pitfalls to Avoid
- Never administer meropenem before dialysis sessions—this leads to premature drug removal and subtherapeutic levels 2
- Avoid reducing individual doses in moderate renal impairment; instead extend the interval 2
- Do not underdose ICU patients with normal renal function who have increased clearance 3
- Monitor for neurological toxicity when trough concentrations exceed 64 mg/L, particularly in patients with renal impairment or CNS infections 2, 3
- Consider residual diuresis in CRRT patients, as this significantly impacts total drug clearance and may necessitate higher doses 2
- When using continuous infusion, prepare new infusion bags every 6 hours due to limited stability at room temperature 3