Population pharmacokinetic analysis and dosing optimization of colistin sulphate in lung transplant recipients with pneumonia: A prospective study

Objective

Currently, there is a lack of information on the clinical pharmacokinetics (PK), effectiveness, and safety of colistin sulphate (CS) in lung transplant recipients. This study aims to improve CS dosing regimens and evaluate its population PK in lung transplant recipients.

Methods

This study evaluated the clinical efficacy, microbiological efficacy, and adverse events of CS in lung transplant recipients. The NONMEM program was employed to construct the population PK model, and Monte Carlo simulations were executed to establish dosing regimens according to the probability of target attainment (PTA).

Results

The study included 146 CS concentrations, spanning from 0.05 to 4.18 mg/L from 39 lung transplant recipients with multidrug-resistant Gram-negative bacteria. 26 (66.67%) patients successfully eradicated bacteria, and 30 (76.92%) patients had clinical cure or improvement. Additionally, only 2 (5.13%) patients developed CS-related nephrotoxicity. The PK profile was effectively represented by a one-compartmental model with linear elimination. Creatinine clearance and concomitant furosemide use were recognized as covariates influencing the clearance of CS. Based on the PTA results, a daily dosage of 1.5 million IU, divided into 2–3 administrations, could attain a PTA exceeding 90% for MIC ≤ 1 µg/mL at creatinine clearance of about 110 mL/min. However, this regimen would lead to insufficient exposure for MIC ≥ 2 µg/mL.

Conclusions

The clearance of CS is significantly influenced by concomitant furosemide use and renal function. The currently recommended dosing regimens by label sheet may result in subtherapeutic exposure for MIC exceeding 1 mg/L in lung transplant recipients.