RELATIVE POTENCY OF ELTANOLONE, PROPOFOL, AND THIOPENTAL FOR INDUCTION OF ANESTHESIA

Background: The primary purpose of this investigation was to determine the relative potency of eltanolone, a new steroid hypnotic, and propo fol and thiopental when used for induction of general anesthesia. In a ddition, the induction characteristics of propofol and eltanolone were compared. Methods: One hundred seventy-five patients, premedicated wi th lorazepam 1 mg orally, randomly received one of six different doses of either eltanolone or propofol. The probability of successful induc tion (defined as not responsive to verbal commands within 2 min) was r elated to the logarithm of the dose for each drug by means of logistic regression analysis. Estimates of ED(50) and ED(95) for each drug wer e obtained. The incidence of side effects was compared for eltanolone and propofol. The potency of thiopental was determined in a parallel s tudy, using an identical methodology in 105 patients receiving one of seven different doses of the barbiturate. Results: The relative potenc y of eltanolone was 3.2 times (95% confidence interval 2.7-3.8) greate r than propofol and 6.0 times (5.3-6.9) greater than thiopental. ED(50 ) and ED(95) values for eltanolone were 0.46 (0.40-0.52) and 0.82 (0.6 8-1.28) mg.kg(-1), respectively. Compared to propofol, induction of an esthesia with eltanolone is characterized by a lower incidence of inje ction pain (3.5% vs 58%) and apnea (1.2% vs. Conclusions: Eltanolone a ppeared to be an effective induction agent that is 3.2 times more pote nt than propofol and 6 times more potent than thiopental. Its use was associated with less pain on injection than was propofol.