Liposomal amphotericin B exposure in critically ill patients: a prospective pharmacokinetic study

Liposomal amphotericin B (L-AmB) is a broad-spectrum antifungal drug. Little is known about its pharmacokinetics (PK) in critically ill patients. The aim of this study was to document the PK of L-AmB in this population. It was also explored if covariates may be identified that influence its exposure. All adult, critically ill patients (at the intensive care unit or hematology ward) treated with L-AmB between October 2016 and January 2020 were eligible for this study. The administered dose was left at the discretion of the treating clinician. Plasma samples were collected at predose and 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 20 h and 24 h postdose at an early (day 2-3) and/or later (≥ day 6) treatment day. Additionally, daily trough concentrations were collected until day 14. Thirty-one of 33 included patients were evaluable; their median [IQR] age and body weight was 59 [54-64] years and 68 [59-77] kg, respectively. L-AmB was administered at doses between 2.7 mg/kg and 12.3 mg/kg, with a median [IQR] trough concentration of 3.1 [2.0-4.7] mg/L. The overall median area under the 24h-concentration-time curve (AUC0-24) and peak plasma concentration (Cmax) were 169.0 [117.0-253.0] mg.h/L and 23.2 [16.9-33.7] mg/L, respectively. A considerable intra-and interpatient PK variability for Cmax and AUC0-24 was observed but no explaining variables, except the administered dose, could be identified. The PK of L-AmB in critically ill patients was documented. A considerable variability in exposure was observed between and within patients, however, not associated with a multitude of patient-related characteristics.