What is the dose of meropenem for a patient with a complicated urinary tract infection?

Meropenem Dosing for Complicated Urinary Tract Infection

For complicated urinary tract infections, administer meropenem 1 gram IV every 8 hours for 5-7 days. 1, 2

Standard Dosing Regimen

• The recommended dose is meropenem 1 gram IV every 8 hours, which represents the standard regimen for complicated UTIs in patients with normal renal function 1, 2
• Treatment duration should be 5-7 days for most complicated UTIs, though this may be extended based on clinical response and source control adequacy 3, 1, 2
• No loading dose is required for meropenem therapy 1

Extended Infusion Considerations

• Consider extended infusion over 3 hours if the pathogen's meropenem MIC is ≥8 mg/L to optimize pharmacodynamic targets 1, 2
• Extended infusion is particularly important for resistant organisms or critically ill patients to maximize time above MIC 1
• Standard infusion time is adequate for most susceptible organisms 1

Resistant Organism Alternatives

If carbapenem-resistant Enterobacterales (CRE) are identified, alternative regimens include:

• Meropenem-vaborbactam 4 grams IV every 8 hours (preferred for CRE) 3, 2
• Ceftazidime-avibactam 2.5 grams IV every 8 hours 3, 2
• Imipenem-cilastatin-relebactam 1.25 grams IV every 6 hours 3, 2
• Aminoglycosides as monotherapy: gentamicin 5-7 mg/kg/day IV once daily or amikacin 15 mg/kg/day IV once daily (only for UTIs, not other infection sites) 3, 2

Renal Dosing Adjustments

• Patients with creatinine clearance below 50 mL/min require dose reduction to 1 gram every 12 hours 4
• The elimination half-life of meropenem increases from approximately 1 hour in healthy patients to up to 13.7 hours in anuric patients 5
• For patients on continuous venovenous hemofiltration (CVVH), maintain 1 gram every 8 hours as approximately 25-50% of the drug is removed by CVVH 5, 6
• Approximately 50% of meropenem is eliminated by intermittent hemodialysis, requiring post-dialysis supplementation 5

Critical Pitfalls to Avoid

• Do not use meropenem for MRSA or VRE, as it lacks activity against these organisms 1
• Avoid underdosing in critically ill patients or those with resistant organisms—consider infectious disease consultation for complex cases 1, 2
• Do not discontinue therapy prematurely if clinical response is incomplete, even if the standard 5-7 day course has been completed 1
• Ensure adequate source control (e.g., removal of infected stones, drainage of abscesses) as antibiotics alone may be insufficient 1