What is the recommended dosage of Meropenem (generic name) for a child with a bacterial infection and potentially impaired renal function?

Meropenem Dosing in Children

For children ≥3 months of age with bacterial infections and normal renal function, administer meropenem 20 mg/kg IV every 8 hours; for neonates, dosing varies by postnatal age and weight, ranging from 20 mg/kg every 12 hours to every 8 hours. 1

Standard Pediatric Dosing by Age Group

Neonates (Birth to 4 Weeks)

Postnatal age 0-7 days:

• 20 mg/kg every 12 hours regardless of weight 1

Postnatal age >7 days:

• Weight 1200-2000 g: 20 mg/kg every 12 hours 1
• Weight >2000 g: 20 mg/kg every 8 hours 1

Infants and Children ≥3 Months

• Standard dose: 20 mg/kg every 8 hours 1
• This dosing achieves adequate plasma concentrations above the MIC for most susceptible pathogens 2

Pharmacokinetic Considerations

Meropenem demonstrates consistent pharmacokinetics across pediatric age groups:

• Mean half-life: 1.13 hours 2
• Volume of distribution: 0.43 L/kg 2
• Approximately 55% recovered unchanged in urine within 12 hours 2
• No significant age-dependent or dose-dependent effects on pharmacokinetic parameters in children 2 months to 12 years 2

Dosing for Specific Infections

Severe Infections and Meningitis

For bacterial meningitis or severe CNS infections:

• 40 mg/kg every 8 hours in children 3
• This higher dose achieves adequate CSF penetration, with levels of 0.64-4.22 mcg/mL documented in purulent meningitis 3

Infections with Resistant Organisms

For organisms with higher MICs (≥4 mg/L):

• Consider extended infusion over 3 hours rather than standard 30-minute infusion 4
• Standard bolus dosing of 20 mg/kg every 8 hours may be inadequate for organisms with MIC ≥1 mg/L 4
• Extended 3-hour infusion improves probability of target attainment (40% time above MIC) from 0.678 to 1.000 for MIC of 1 mg/L 4

Renal Function Adjustment

Dosage reduction is required for impaired renal function, though specific pediatric guidelines are limited in the provided evidence. The standard dosing assumes normal renal function with clearance of approximately 5.63 mL/min/kg 2. Monitor renal function and adjust accordingly, as approximately 55-68% of the drug is renally excreted 2, 3.

Administration Guidelines

Standard administration:

• Administer by 30-minute IV infusion for routine dosing 3
• For severe infections or resistant organisms, use 3-hour extended infusion 4
• Maximum daily dose in clinical studies reached 173 mg/kg/day divided four times daily 3

Safety Profile

Meropenem demonstrates excellent tolerability in pediatric patients:

• No significant adverse effects reported in pharmacokinetic studies 2
• Safety profile similar between adults and children 5
• Lower incidence of seizures compared to imipenem, making it particularly suitable for meningitis 5
• Most common adverse events: diarrhea, rash, nausea/vomiting, and transient laboratory abnormalities 5

Clinical Efficacy Data

Documented efficacy rates in pediatric infections:

• Purulent meningitis: 100% efficacy (11 patients) 3
• Pneumonia: 98.8% efficacy (173 patients) 3
• Urinary tract infections: 100% efficacy (65 patients) 3
• Overall bacteriological eradication: 96.7% (260/269 strains) 3

Critical Pitfalls to Avoid

Do not use standard bolus dosing for:

• Organisms with MIC ≥1 mg/L without considering extended infusion 4
• Severe infections where inadequate drug exposure may lead to treatment failure 4

Do not underdose in meningitis:

• Standard 20 mg/kg dosing is insufficient for CNS infections; use 40 mg/kg every 8 hours 3

Do not ignore renal function:

• Meropenem is primarily renally cleared and requires dose adjustment in renal impairment 2