Colistin is used systemically in critically ill patients for treatment of infections caused by multi-drug resistant (MDR) Gram-negative bacteria, e.g., Acinetobacter baumanii. It is potentially nephro- and neurotoxic. It is recommended to decrease the dose of colistin in case of renal impairment or renal replacement therapies (RRT) but clear recommendations are not available yet. The aim of this retrospective study was to determine colistin use patterns in critically ill patients in Pauls Stradiņš University Hospital. Forty patients were included in this study. The most common indications for colistin were pneumonia associated with mechanical ventilation or sepsis caused by MDR A. baumanii. Median duration of colistin therapy was 11.5 (IQR 7.0; 17.0) days and median cumulative dose was 91.5 (43.0; 150.0) million units (MU). The usual regimen was 9 MU as loading dose and 3 MU three times daily as maintenance dose, but in case of renal impairment and RRT colistin regimens varied a lot between the patients. In 21% (7 from 33) of cases, acute kidney injury (AKI) was observed during colistin therapy (serum creatinine increases more than twice from baseline). All these AKI cases occurred in patients with previously normal renal function and none of the patients in this group needed RRT.
