PK targets were achieved in 59.6% of ICU patients for amikacin and in 2.2% of ICU patients for gentamicin.

Factors associated with PK target achievement were dose per kg and renal clearance.

PK/PD targets were achieved for all patients infected with susceptible bacteria.

We aimed to evaluate the probability to achieve PK-PD targets in patients with sepsis hospitalized in the intensive care unit (ICU) after a single dose of 30 mg/kg of amikacin or 8 mg/kg of gentamicin.

This single-center prospective study included 138 ICU patients with severe sepsis or septic shock with an indication for intravenous amikacin (N = 89) or gentamicin (N = 49). Maximum concentration (Cmax) was measured 30 minutes after infusion completion. PK/PD objectives were respectively Cmax ≥ 60 mg/L and ≥ 30 mg/L for amikacin and gentamicin for empirical therapy, and a Cmax/MIC ratio ≥ 8, as per French guidelines.

The median Simplified Acute Physiology Score II was 43 and ICU case fatality rate was 34.8%. A causative bacterial agent was identified in 94 patients (68.1%). Three pathogens had acquired aminoglycoside resistance and 15 were naturally resistant. The targeted Cmax for the first dose was achieved in 53 patients (59.6%) receiving amikacin, and one (2.2%) patient receiving gentamicin. Cmax/MIC ratio ≥ 8 was obtained in all patients infected with susceptible pathogens (N = 72). Factors associated with Cmax ≥ 60 mg/L of amikacin in multivariate analysis were dose per kg of adapted body weight (OR = 1.39, P < 0.001) and renal clearance estimated with CKD-EPI formula (OR = 0.98, P = 0.003).

Despite high doses, amikacin and gentamicin first Cmax remain dramatically low in ICU patients. However, an adequate Cmax/MIC ratio was reached in all patients.

Amikacin

Gentamicin

PK/PD

Intensive care unit

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