Pharmacokinetics of etomidate associated with prolonged i.v. infusion

Plasma concentrations of etomidate have been measured in six patients who required intermittent positive pressure ventilation following surgery. There was an approximately linear relationship between the plasma concentration and the rate of infusion of etomidate. The drug exhibited linear pharmacokinetics over a 10-fold variation in plasma concentration. The decrease in the plasma concentration after discontinuing the infusion was consistent with a three-compartment pharmacokinetic model. The plasma terminal half-life was found to be about 5.5 h, and the clearance calculated to be 0.025 litre kg-1 min-1.