Monitoring therapeutic colistin concentrations in critically ill patients admitted to a tertiary care hospital

Objective: The purpose of this study was to determine the optimal dosage of colistin according to colistin concentrations and the creatinine clearance rate (CLCR) in 21 critically ill haemodialysis and non-haemodialysis patients with Gram-negative bacterial infections admitted to a tertiary care hospital in India. Methodology and design: Blood samples were collected from patients after the fourth dose of colistin to measure the trough concentrations of colistin using high-pressure liquid chromatography. Additionally, CLCR was calculated using the Cockcroft-Gault equation, and serum creatinine values were used to assess nephrotoxicity. Results: The optimum therapeutic range of colistin in plasma was considered to be 5–17 µg/ml. Three haemodialysis patients had high plasma colistin concentrations of 25.27 ± 6.65 µg/ml and three non-haemodialysis patients had high colistin concentrations of 36.56 ± 17.26 µg/ml. Six patients had a CLCR value < 20 ml/min. The dosage of colistin in patients with high colistin plasma concentrations and low CLCR was reviewed. Conclusion: For this group of patients, based on trough concentrations of colistin, CLCR, and clinician’s clinical experience, a reduction of colistin dosage in haemodialysis patients and non-haemodialysis patients, respectively, was suggested to lower elevated plasma colistin concentrations. This dosage reduction may reduce the signs associated with nephrotoxicity and promote improvements in patient life and colistin-related outcomes. © 2018, Springer Nature Switzerland AG.