[Propofol potentiates the neuromuscular blocking effects of vecuronium in man]

The possible interaction between vecuronium and propofol has been investigated in 40 healthy (ASA I-II) patients. They were randomly allocated to two groups according to the method of anesthesia; continuous propofol infusion group (propofol) and droperidol and fentanyl group (control). The electromyographic response of abductor digiti minimi was monitored at 20-s interval after train-of-four stimulations of the ulnar nerve. The ED50 and ED95 (dose required to produce a 50% and 95% depression of twitch tension, respectively,) of vecuronium in the propofol group (n = 20) were 29.4 +/- 0.5 and 56.6 +/- 2.1 micrograms.kg-1 (mean +/- SEM), and in the control group (n = 20), 36.7 +/- 1.8 and 73.6 +/- 5.2 micrograms.kg-1, respectively. Under propofol anesthesia, the cumulative dose-response curves of vecuronium were shifted to the left when compared with control ED50 and the slope showed that propofol had potentiated the action of vecuronium.