What is the recommended dose of meropenem (Merrem) for a 100 lb female patient with pneumonia and normal renal function?

Meropenem Dosing for Pneumonia in a 100 lb Female Patient with Normal Renal Function

The recommended dose of meropenem for a 100 lb (45.4 kg) female patient with pneumonia and normal renal function is 1 gram intravenously every 8 hours. 1

Dosing Rationale

The dosing recommendation is based on current guidelines for hospital-acquired pneumonia treatment:

• The 2016 Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) guidelines specifically recommend meropenem 1 gram IV every 8 hours for pneumonia 1
• This standard dosing is appropriate for patients with normal renal function 2
• The 2005 ATS guidelines also support this dosing regimen for pneumonia 1

Weight-Based Considerations

While the patient weighs 100 lb (45.4 kg), weight-based dosing adjustments are not necessary in this case:

• Meropenem standard adult dosing applies to this patient as she is in the adult weight range
• The FDA-approved dosing for adults with pneumonia is 1 gram every 8 hours 2
• Weight-based dosing (20 mg/kg) is typically reserved for pediatric patients 2

Administration Method

For optimal efficacy in pneumonia:

• Administer as an intravenous infusion over 15-30 minutes 2
• Extended infusion over 3 hours may be considered for improved pharmacodynamic target attainment, especially for more resistant pathogens 3

Monitoring Recommendations

• No routine drug level monitoring is required for meropenem 1
• Monitor renal function regularly as meropenem is primarily excreted by the kidneys 4
• Assess clinical response within 48-72 hours of initiating therapy

Duration of Therapy

• Standard duration for pneumonia is 7 days 5
• Treatment should be extended if the infection has not improved within this time period 5
• Clinical stability (temperature ≤37.8°C, heart rate ≤100 beats/min, respiratory rate ≤24 breaths/min, systolic blood pressure ≥90 mmHg, oxygen saturation ≥90%) should guide duration 5

Important Considerations and Potential Pitfalls

1. Renal function changes: If renal function deteriorates during treatment, dose adjustment will be necessary according to the following schedule 2:

   • CrCl 26-50 mL/min: 1 gram every 12 hours
   • CrCl 10-25 mL/min: 500 mg every 12 hours
   • CrCl <10 mL/min: 500 mg every 24 hours

2. Potential adverse effects:

   • Common: headache, nausea, constipation, diarrhea, anemia, vomiting, and rash 2
   • Serious: seizures (particularly with higher doses), Clostridioides difficile-associated diarrhea 2

3. Drug interactions:

   • Valproic acid: meropenem can reduce valproic acid levels, increasing seizure risk 2
   • Probenecid: inhibits renal excretion of meropenem and is not recommended for co-administration 2

By following these dosing guidelines, you can ensure appropriate antimicrobial therapy for this patient with pneumonia while minimizing the risk of adverse effects and optimizing clinical outcomes.