Assessment of the National French recommendations regarding the dosing regimen of 8mg/kg of gentamicin in patients hospitalised in intensive care units

To assess the French National Agency for Medicines and Health Products Safety (ANSM) guidelines concerning the peak plasma concentration (Cmax) of gentamicin when using a loading dose of 8mg/kg administered in patients hospitalised in the intensive care unit (ICU). A prospective observational cohort study conducted in one ICU. During the study period, 34 patients with a median simplified acute physiology score 2 of 54 [44–70] received a median dose of 8 [7.9–8.1] mg/kg of gentamicin. The median Cmax was 17.5 [15.4–20.7] mg/L and no patient had a Cmax>30mg/L. Twenty-four of 34 patients (71%) had a Cmax>16mg/L. Following multivariate analysis, the only factor associated with Cmax30mg/L [which corresponds to approximately 8 times the minimal inhibiting concentrations (MIC) breakpoints for Pseudomonas aeruginosa and Enterobacteriaceae with intermediate sensitivity] of gentamicin as recommended by ANSM guidelines seems impossible to obtain with a loading dose of 8mg/kg in the ICU. A loading dose of 8mg/kg should probably not be used in the empiric antibiotic treatment of infection due to non-fermenting Gram-negative bacilli and Enterobacteriaceae with intermediate sensitivity whose MIC breakpoint is 4mg/L. A Cmax>16mg/L was not reached in almost 30% of patients, particularly in the group with a positive fluid balance who require higher doses than currently recommended.