About Meropenem Renal Dosing

This section provides clinical context for the Meropenem Renal Dose Calculator.

Meropenem is a broad-spectrum carbapenem antibiotic used to treat a variety of severe bacterial infections. Since it is primarily eliminated by the kidneys, its dosage must be adjusted in patients with renal impairment to prevent drug accumulation and potential toxicity, such as seizures. This process requires an accurate estimation of the patient's renal function, commonly calculated as creatinine clearance (CrCl).

The Cockcroft-Gault equation is a widely used method for estimating CrCl and serves as the foundation for the dosing recommendations provided by this tool, aligning with guidance from drug manufacturers and clinical practice resources.

Understanding the Calculator's Outputs

The tool generates several key data points to guide clinical decisions.

• Creatinine Clearance (CrCl): The primary output, calculated in mL/min using the Cockcroft-Gault formula. This value categorizes the patient's level of renal function.
• Renal Function Category: A qualitative description based on the CrCl value (e.g., Normal Function, Mild-Moderate Impairment, Severe Impairment).
• Recommended Regimen: A specific meropenem dose and dosing interval tailored to the patient's CrCl, baseline indication (e.g., standard infection vs. meningitis), and chosen infusion strategy.
• Dosing Rationale: A brief explanation for why the dose adjustment is recommended, linking the change to the calculated level of renal impairment.

How to Use the Calculator

Enter the following patient parameters for an accurate dosing recommendation.

To calculate the appropriate meropenem dose, input these key patient variables:

• Age: Patient's age in years.
• Weight: Use the patient's actual body weight. Clinical judgment is advised for obese patients, where adjusted or ideal body weight may be more appropriate.
• Biological Sex: Used for the Cockcroft-Gault formula, which includes a correction factor for females.
• Serum Creatinine (SCr): The patient's most recent SCr level.
• Indication / Severity: Select the baseline regimen appropriate for the infection being treated (e.g., 1g q8h for standard infections or 2g q8h for meningitis or cystic fibrosis exacerbations).
• Infusion Strategy: Choose between a standard (30-minute) or extended (3-hour) infusion. Extended infusions can optimize the time the drug concentration remains above the minimum inhibitory concentration (T>MIC), which may improve outcomes for certain infections.

Dosing Overview

Summary of meropenem dose adjustments based on creatinine clearance (CrCl).

For Standard Infections (Baseline 1g q8h):

• CrCl >50 mL/min: 1 gram IV every 8 hours
• CrCl 26-50 mL/min: 1 gram IV every 12 hours
• CrCl 10-25 mL/min: 500 mg IV every 12 hours
• CrCl <10 mL/min: 500 mg IV every 24 hours

For Meningitis / Cystic Fibrosis (Baseline 2g q8h):

• CrCl >50 mL/min: 2 grams IV every 8 hours
• CrCl 26-50 mL/min: 2 grams IV every 12 hours
• CrCl 10-25 mL/min: 1 gram IV every 12 hours
• CrCl <10 mL/min: 1 gram IV every 24 hours

Switching Antibiotics

Guidance on transitioning to or from meropenem.

The decision to switch to or from meropenem is a clinical judgment based on factors like culture and sensitivity results, patient response, local antimicrobial stewardship guidelines, and the specific infection. This tool does not provide recommendations for switching between different antibiotics. Consultation with an infectious diseases specialist or pharmacist is recommended for complex cases.

Missed Dose Protocol

Guidance for managing a missed dose of meropenem.

Meropenem is typically administered by healthcare professionals in a supervised setting. If a dose is missed, it should be given as soon as possible. However, if it is nearly time for the next scheduled dose, the missed dose should be skipped to avoid double dosing. The regular dosing schedule should then be resumed. Do not administer two doses at once.

Safety Alerts

Key warnings and precautions associated with meropenem therapy.

• Hypersensitivity Reactions: Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported. Use with caution in patients with a history of allergy to beta-lactam antibiotics.
• Seizure Potential: Seizures have been reported, particularly in patients with pre-existing CNS disorders or compromised renal function. Adherence to recommended dosing is critical to minimize this risk.
• Clostridioides difficile-Associated Diarrhea (CDAD): As with most antibacterial agents, CDAD can occur and may range in severity from mild diarrhea to fatal colitis.
• Drug Interactions: Co-administration with valproic acid or divalproex sodium is not recommended, as it can significantly reduce valproic acid concentrations, potentially leading to loss of seizure control.

Frequently Asked Questions

Common questions about meropenem dosing and the calculator.

References

Authoritative sources used for dosing recommendations.

• 1. MERREM® IV (meropenem for injection) Prescribing Information. Pfizer Inc. Revised: 9/2023. Available at: FDA.gov
• 2. Meropenem. In: Lexicomp Online®, Lexi-Drugs®. Wolters Kluwer Health, Inc. Riverwoods, IL. Accessed October 2023.
• 3. Kalil AC, Metersky ML, Klompas M, et al. Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis. 2016;63(5):e61-e111.
• 4. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.