Colistin use in critically ill patients: in search of the optimal dosing.

the recent article in CHEST (December 2010) by Imberti et al,1 which described steady-state serum pharmacokinetics and BAL concentration of colistin after IV administration of colistin methanesulfonate (CMS) in adult patients with ventilator-associated pneumonia caused by gram-negative bacteria raises questions about whether the currently used dosages of colistin methanesulfonate are appropriate in the critically ill patient, in whom larger distribution volume and increased plasma concentrations of α1-acid glycoprotein, an acute-phase protein with polymyxin-binding capabilities,5 may result in free colistin concentrations that are lower than those expected