Amikacin use in critically ill patients requiring renal replacement therapy: the AMIDIAL-ICU study

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is common in intensive care units (ICUs), yet optimal amikacin dosing in this context remains poorly understood.

We conducted a prospective observational study across 18 French hospitals from April 2020 to January 2022. Adult ICU patients (aged > 18 years) receiving their first amikacin dose while on RRT were included. Data on demographics, RRT modalities, amikacin dosing, and therapeutic drug monitoring were collected. Using a pharmacokinetic modeling approach, we evaluated various amikacin regimens and simulated target attainment probabilities across different minimum inhibitory concentrations (MICs).

A total of 111 patients were included, with approximately two-thirds receiving continuous RRT. The median amikacin dose was 27 (25-30) mg/kg. Amikacin peak (Cmax) and trough concentrations were monitored in 53 (47.8%) and 76 (68.5%) patients, respectively. Continuous RRT and a history of chronic kidney disease reduced dialytic clearance. For a MIC ≤ 4 mg/L, a 15 mg/kg amikacin dose achieved Cmax/MIC and AUC/MIC targets in ≥ 90% of patients on intermittent dialysis, while 20 mg/kg was required for those on continuous dialysis. For a MIC = 8 mg/L, a 30 mg/kg dose was necessary to achieve Cmax/MIC ≥ 8.

Our findings highlight suboptimal adherence to amikacin monitoring guidelines in ICU patients on RRT. Using pharmacokinetic modeling, we identified amikacin dosing recommendations ranging from 15 to 35 mg/kg to optimize efficacy and minimize risks, depending on MIC and dialysis modality.