ChEBI: A mixture where R = H or Me. Colistin in which each of the primary amino groups is converted to the corresponding aminomethanesulfonic acid sodium salt, commonly by the action of formaldehyde followed by sodium bisulfite. A polymyxin antibiotic derivative,
it is used in the treatment of severe infections, particularly of multidrug-resistant Gram-negative bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii.
Pharmacokinetics
Colistin is administered intravenously as the non-active prodrug, colistin methanesulfonate sodium (CMS). Colistin methanesulfonate sodium (Colistin sodium methanesulfonate) is eliminated mainly by renal clearance. If CMS is cleared rapidly by the kidney, less CMS is converted to colistin resulted in low colistin that could lead to ineffective antibacterial therapy. In patients with normal renal function (1–2 MIU of CMS), approximately 30–60% of a dose of CMS is converted to colistin. The renal clearance of CMS is much more efficient than the conversion of CMS to colistin. Therefore, to achieve a targeted concentration of >2 mg/L, patients must receive four to five times the amount of CMS. There was wide variability of colistin Cmax values (0.6–8.7 mg/L) in plasma among single-dose studies receiving 2–3 MIU of CMS in critically ill patients with preserved renal function. Almost none of the ICU patients achieved a colistin concentration of more than 2 mg/L in the Plachouras et al. and Mohamed et al. studies[4].
Safety Profile
Human poison by intramuscular route. Experimental poison by intramuscular, intraperitoneal, subcutaneous, and intravenous routes. Mildly toxic by ingestion. An experimental teratogen. Human systemic effects by intramuscular route: convulsions or effect on seizure threshold, change in motor activity, change in lrldney tubules, and urine volume decrease or anuria. Experimental reproductive effects. Used as an antibiotic. When heated to decomposition it emits very toxic fumes of NOx, SOx, and NazO
