Dose-response Relationships of Doxacurium Chloride in Humans during Anesthesia with Nitrous Oxide and Fentanyl, Enflurane, Isoflurane, or Halothane

Publisher Website
Google Scholar
Abstract
In a two-part study, the dose-response relationships of doxacurium chloride (BW A938U) were evaluated during general anesthesia maintained with commonly used anesthetic techniques. In part 1, cumulative dose-response methodology was used to establish the ED95 of doxacurium in 36 patients receiving 70% nitrous oxide and fentanyl, or 50% nitrous oxide and either 1.26% enflurane, 0.84% isoflurane, or 0.57% halothane anesthesia. Mechanomyographic response to train-of-four stimulation was used to monitor neuromus-cular blockade. The peak effect of doxacurium following each 5 μg/kg incremental dose was noted and a log-probit dose-response curve was constructed for each individual patient. The median ED50S were 11 μg/kg, 6 μg/kg, 8 μg/kg, and 8 μg/kg for patients receiving fentanyl, enflurane, isofurane, or halothane anesthesia, respectively. The median ED93S were 24 μg/kg, 14 μg/kg, and 19 μg/kg for patients receiving fentanyl, enflurane, isoflurane, and halothane anesthesia, respectively. In part 2, 72 additional patients received·rapid single injection of the ED95 (n = 36) or 2 X ED95 (n = 36) of doxacurium appropriate for the administered anesthetic as estimated from part one of the study. Peak effects of the ED95 given as single injections correlated well with the results in part 1. There was a dose-dependent reduction In the time required to reach maximal blockade, and a corresponding increase in the duration of effect when twice the ED95 was administered compared with that following the ED95; mean onset times from injection to maximum block were 10–13 min for the ED95S and 5–7 min for 2 X ED95S, and mean times from injection to 25% recovery were 48–60 min for the ED95S and 106–109 min for 2 X ED95S. The anesthetic agent used did not result in significant differences between these mean times, but there was a significant difference when the two doses were compared for each anesthetic technique. The study results indicate that, when using the potent volatile agents, doses of doxacurium can be decreased 20–40% from doses required during anesthesia with nitrous oxide and fentanyl.

This publication has 0 references indexed in Scilit: