Amikacin in emergency surgery: How to dose it optimally?

Area of Science:

• Pharmacology
• Critical Care Medicine
• Infectious Diseases

Background:

• Amikacin remains a key antibiotic for emergency surgical procedures, particularly intra-abdominal infections (IAI).
• Existing guidelines recommend 15-20 mg/kg/24h for IAI, but optimal dosing in emergency surgery requires further investigation.

Purpose of the Study:

• To analyze amikacin pharmacokinetics (PK) and dosage requirements in patients undergoing emergency surgery.
• To identify an optimal dosing strategy for amikacin in this critical setting.

Main Methods:

• Retrospective analysis of 84 patients receiving amikacin for emergency surgery.
• Measurement of peak (Cmax) and trough (Cmin) amikacin concentrations after the first dose.
• Utilized BestDose software for PK analysis and simulation; Classification and regression tree analysis for determinant identification.

Main Results:

• Despite a median initial dose of 25 mg/kg, 32% of patients failed to reach the target Cmax (>64 mg/L).
• Doses ≤21.5 mg/kg were associated with failure to achieve target concentrations.
• A dose of 30 mg/kg (total or corrected body weight) or a fixed 2500 mg dose showed highest target attainment.

Conclusions:

• Current recommended amikacin dosages are not optimal for emergency surgery patients.
• A fixed initial dose of 2500 mg could simplify and enhance amikacin dosing efficacy in this population.
• Ideal body weight, age, and renal function are key determinants for optimal amikacin dosing.