[Determination of the dose-effect curve of vecuronium in anesthetized man].

Dose-response curves have been determined in 37 healthy subjects, after injection of a single bolus of Organon NC 45 (vecuronium or Norcuron). The doses used were 0.0125, 0.025, 0.037 and 0.05 mg X kg-1. The ulnar nerve was stimulated at the wrist and the force of thumb adduction measured. No premedication was used. Anesthesia was induced with thiopentone and fentanyl, and maintained by a nitrous oxide/oxygen mixture under controlled ventilation. PaCO2 was 37 +/- 0.5 mmHg and temperature 36.8 +/- 0.1 degrees C. The effective doses (ED) were: ED50 at 0.024 mg X kg-1, ED90 at 0.034 mg X kg-1 and ED95 at 0.037 mg X kg-1. At 0.05 mg X kg-1, the degree of twitch inhibition was 99.2 +/- 0.6%, the delay of maximum effect was 7.7 +/- 1.4 min, and the length of action (up to 90% recovery) was 27.2 +/- 2.3 min. Vecuronium is therefore a potent neuromuscular blocking agent with a relatively short duration of action.