Comparison of vecuronium with ORG 9487 and their interaction

Purpose: To compare the pharmacodynamic behaviour of vecuronium with that of ORG 9487, we measured the time-course of action of equipotent doses of ORG 9487 and vecuronium and investigated their mutual interaction when given in succession. Methods: Sixty ASA I-II patients were anaesthetized with thiopentone, fentanyl, halothane and nitrous oxide and assigned randomly to four groups. Each patient received an initial dose (ID) of either vecuronium (V) or OPG 9487 (O) followed by maintenance doses (MDn) of either V or O (ID/MD: O/O, V/O, O/V and V/V. The time course of action was measured mechanomyographically, determining the duration until 25% recovery of the single twitch (DUR25). Results: The onset time of an ID of ORG 9487 was shorter than that of an ID of vecuronium (96 vs 203 sec, P