What is the recommended dosage of Meropenem for Extended-Spectrum Beta-Lactamase (ESBL) Urinary Tract Infection (UTI)?

Recommended Dosage of Meropenem for ESBL UTI

For ESBL urinary tract infections, meropenem should be administered at 1 g IV every 8 hours for 5-7 days. 1

Rationale for Dosing Recommendation

Meropenem is an appropriate choice for ESBL UTIs due to its excellent activity against extended-spectrum beta-lactamase producing organisms. According to the 2022 guidelines for treatment of infections due to multidrug-resistant organisms, meropenem is recommended for complicated urinary tract infections caused by resistant organisms 1.

Dosing Details:

• Standard dose: 1 g IV every 8 hours
• Administration: Intravenous infusion
• Duration: 5-7 days for complicated UTIs 1
• Extended infusion: Consider extended infusion over 3 hours if meropenem MIC is ≥ 8 mg/L 1

Special Considerations

Renal Adjustment

• Dose adjustment is required for patients with renal impairment
• For patients on continuous venovenous hemofiltration (CVVH), 1 g every 8 hours is still appropriate 2

Antimicrobial Stewardship

• Reserve meropenem for confirmed ESBL infections to prevent development of resistance
• Recent studies show alarming increases in carbapenem resistance (4.9% meropenem resistance in some settings) 3

Alternative Options for ESBL UTIs

If meropenem cannot be used, consider these alternatives:

1. Ceftazidime/avibactam: 2.5 g IV every 8 hours (weak recommendation, low-quality evidence) 1
2. Meropenem/vaborbactam: 4 g IV every 8 hours (weak recommendation, moderate-quality evidence) 1
3. Imipenem/cilastatin/relebactam: 1.25 g IV every 6 hours (weak recommendation, moderate-quality evidence) 1
4. Aminoglycosides (if susceptible):
   • Gentamicin: 5-7 mg/kg/day IV once daily
   • Amikacin: 15 mg/kg/day IV once daily
   • Plazomicin: 15 mg/kg IV every 12 hours 1

Efficacy Data

Meropenem has demonstrated high efficacy against ESBL-producing organisms:

• 95% susceptibility rate for ESBL-producing organisms 3
• Clinical response rates of 93-100% for UTIs when administered intramuscularly 4

Potential Pitfalls and Caveats

1. Emerging resistance: Monitor for carbapenem resistance, especially in patients with prior meropenem exposure 3
2. Duration: Do not extend treatment beyond 7 days unless clinically indicated, as unnecessary prolonged therapy increases resistance risk 5
3. Susceptibility testing: Always obtain culture and susceptibility testing before initiating therapy if possible 1
4. Alternative routes: While IV is standard, intramuscular meropenem has shown efficacy in UTIs when IV access is challenging 4

For ESBL-producing E. coli specifically, which is the most common cause of ESBL UTIs, meropenem remains highly effective with susceptibility rates of approximately 95% 3. However, the emergence of carbapenem-resistant Enterobacterales (CRE) is concerning and requires careful antibiotic stewardship.