Update on colistin in clinical practice.

Considerable progress has been made in the last decade towards better understanding of the optimal clinical use of colistin. It has become evident that higher intravenous (iv) colistin methanesulfonate (CMS) doses are important, probably with the addition of a loading dose in critically ill patients. Higher CMS doses lead to increased risk of nephrotoxicity, which seems reversible in most cases. Intravenous colistin is reasonably efficacious, but should continue to be considered only in the absence of safer alternatives. Although theoretically appealing, there is insufficient evidence to support inhaled colistin mono-therapy in non-cystic fibrosis patients. Moreover, the balance of evidence available at present is not in favor of adjunctive inhaled colistin therapy. Intrathecal or intra-ventricular colistin administration are appropriate options for neurosurgical meningitis caused by colistin-susceptible, multidrug resistant gram-negative bacteria. Ongoing randomized, controlled trials will hopefully help decide if combining colistin with a carbapenem, fosfomycin, or rifampicin is of clinical advantage.