Colistimethate sodium is a semi-synthetic polymyxin antibiotic and a prodrug of colistin. It acts by disrupting the bacterial cell membrane, leading to cell death. The drug is mainly effective against multidrug-resistant gram-negative bacteria. Colistimethate sodium is commonly administered intravenously or by inhalation. It is widely used in the treatment of severe infections caused by Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella species. The inhalation form is especially useful in cystic fibrosis patients. It is often reserved for serious infections when other antibiotics are ineffective. Colistimethate sodium helps manage hospital-acquired and ventilator-associated pneumonia. Careful dosing is required due to potential nephrotoxicity and neurotoxicity. Overall, it plays a critical role in treating life-threatening resistant infections
