What is the proper dosing and administration of Meropenem (generic name) for adults with normal renal function and those with impaired renal function?

Meropenem Dosing and Administration Guidelines

Meropenem should be dosed at 1 gram every 8 hours by intravenous infusion over 15-30 minutes for most serious infections in adults with normal renal function, with mandatory dose adjustments for renal impairment. 1

Standard Dosing for Adults with Normal Renal Function

• Intra-abdominal infections: 1 gram every 8 hours 2, 1
• Complicated skin and skin structure infections: 500 mg every 8 hours 1
• Pseudomonas aeruginosa infections: 1 gram every 8 hours 1
• Critical illness/sepsis: 1 gram every 8 hours 2

Administration Methods

• Standard infusion: Administer over 15-30 minutes 1
• Bolus injection: Can be given over 3-5 minutes (5-20 mL) 1
• Extended infusion: Consider 3-hour infusion for critically ill patients or when targeting organisms with higher MICs 3

Renal Dosage Adjustments

Meropenem is predominantly excreted unchanged in the urine (up to 70%), making dosage adjustments essential in renal impairment 4, 5:

Creatinine Clearance (mL/min)	Dose	Dosing Interval
>50	Standard dose	Every 8 hours
26-50	Standard dose	Every 12 hours
10-25	Half standard dose	Every 12 hours
<10	Half standard dose	Every 24 hours

1, 3

Special Patient Populations

Elderly Patients

• For patients >59 years old, consider reducing the dose to 10 mg/kg (approximately 600-750 mg) 3, 6
• Meropenem has shown an excellent safety profile in elderly patients 6

Critically Ill Patients

• Consider therapeutic drug monitoring if available 3, 7
• A loading dose may be beneficial in septic shock 3
• Extended or continuous infusion improves target attainment 3, 7

Renal Replacement Therapy

• Intermittent hemodialysis: Approximately 50% of meropenem is eliminated 4
• CVVH/CVVHDF: 25-53% elimination depending on modality 4, 8
• Dosing should be adjusted based on the specific renal replacement modality 4

Duration of Therapy

• For intra-abdominal infections with adequate source control: 4-7 days 2
• For most serious infections: 7-14 days 3
• Consider shorter duration (5-7 days) if rapid clinical improvement occurs 3

Monitoring During Therapy

• Regular assessment of renal function 3
• Clinical response monitoring (temperature, vital signs) 3
• For critically ill patients or those with fluctuating renal function, therapeutic drug monitoring may be beneficial 7

Common Pitfalls to Avoid

1. Underdosing: Particularly problematic in critically ill patients with augmented renal clearance 4, 7
2. Failure to adjust for renal function: Can lead to drug accumulation and potential toxicity 4, 5
3. Inadequate dosing for resistant organisms: Standard dosing may be insufficient for organisms with higher MICs 7, 8
4. Inappropriate duration: Too short may lead to treatment failure; unnecessarily long increases resistance risk 2, 3

Pediatric Dosing

For completeness, pediatric dosing is as follows:

• Children >3 months with normal renal function:
  • Intra-abdominal infections: 20 mg/kg every 8 hours (max 1 gram) 1
  • Complicated skin infections: 10 mg/kg every 8 hours (max 500 mg) 1
  • Meningitis: 40 mg/kg every 8 hours (max 2 grams) 1

Meropenem is generally well-tolerated with a favorable safety profile compared to other carbapenems, with lower risks of seizures (0.1%) even in renally impaired patients 6.