Enhanced Colistin Dosing for Critically Ill Kidney Patients During Dialysis Days, New Study Reveals

Recent research conducted by Monash University and Mahidol University highlights the need for adjusted antibiotic dosing in critically ill patients with acute kidney injury undergoing dialysis. Specifically, the study focuses on colistin, a vital antibiotic used to treat severe multidrug-resistant Gram-negative infections such as pneumonia and bloodstream infections, which often pose a challenge when other treatments fail. Colistin is administered as the inactive prodrug colistin methanesulfonate (CMS), which the body converts into its active form.

The study, published in Clinical Microbiology and Infection, involved 13 critically ill patients receiving sustained low-efficiency dialysis (SLED)—a common dialysis modality for severely ill patients requiring kidney support. Researchers aimed to understand how SLED influences the pharmacokinetics of CMS and colistin, focusing on how quickly the drugs are cleared from the body.

Blood and urine samples collected on both dialysis and non-dialysis days revealed that the elimination rates of CMS and colistin were significantly higher during SLED sessions. Consequently, the researchers recommend administering higher doses of CMS on dialysis days to ensure therapeutic effectiveness. Population pharmacokinetic modeling allowed the team to simulate various dosing strategies, determining optimal regimens that maximize treatment success while minimizing risks.

Lead author Associate Professor Cornelia Landersdorfer emphasized that this research fills a critical knowledge gap, as it is the first to specifically investigate CMS and colistin disposition in patients undergoing SLED using advanced population pharmacokinetic techniques. The findings suggest that increasing CMS doses on dialysis days is necessary due to the accelerated clearance associated with SLED, thus improving the likelihood of effective antimicrobial activity.

This study's insights will guide clinicians in customizing dosing regimens for critically ill patients, potentially leading to better infection management and outcomes. The next step involves applying these pharmacokinetic-based dosing recommendations in clinical practice to validate their efficacy and safety.

For more detailed information, see the full study: Adhiratha Boonyasiri et al, "Disposition of colistin in critically-ill patients on sustained low-efficiency dialysis: a population pharmacokinetic study," available through Clinical Microbiology and Infection.