Polymyxin B – A Renaissance in “Criticare” Infection Management

The ever-increasing plague of nosocomial infections caused by multi-drug resistant (MDR) and extensivelydrug resistant (XDR) Gram negative bacteria like Pseudomonas aeruginosa, Acinetobacter baumanii, and Enterobacteriaceae has led to re-emergence of Polymyxin B and Colistin. They are now considered as the last resort therapy for treating nosocomial infections due to MDR and XDR Gram-negative infections. Polymyxin B and Colistin demonstrate similar microbiological activity which translate into good clinical outcomes. However, in last few years, novel understanding of Polymyxins have emerged with some key clinical differences which have differing clinical implications. The major difference stems from the fact that Polymyxin B is administered as active antibacterial entity whereas Colistin is administered as inactive prodrug form. Owing to a difference in pharmacokinetic handling of Polymyxin B and Colistin, there are differencesin their clinical pharmacokinetics and hence there are potential clinical implications which should be considered by the clinicians to obtain therapeutic efficacy.Multi-drug resistant Pseudomonas aeruginosa, Acinetobacter baumanii and Enterobacteriaceae have become highly prevalent throughout the Indian ICUs. Polymyxin B has shown to be a reliable therapy with proven effectiveness against these MDR Gram-negative strains. Nephrotoxicity is a common adverse effect of Polymyxins. However, owing to different pharmacokinetic features as well as differing renal handling mechanism of Colistin and Polymyxin B, relatively lower incidences of nephrotoxicity is seen in patients treated with Polymyxin B. In this review, we will evaluate the utility and safety of Polymyxin B in critical care infections.Conflict of Interest: Dr. Manish Maladkar, Srividya Sankar and Akshata Karchodi are full time employees of Aristo Pharmaceuticals Pvt. Ltd., India.