[Vecuronium bromide: modification of its pharmacodynamics by etomidate, cimetidine and ranitidine].

After obtaining their informed consent, 60 patients (ASA groups I or II), 18 to 60 years of age were randomly allocated to six groups of 10 persons each. Anesthesia was induced in groups 1, 4, 5 and 6 with 2-3 mg kg-1 thiopentone and in groups 2 and 3 with 0.2-0.3 mg kg-1 etomidate. 20 min before induction, patients in groups 3 and 5 received 5 mg kg-1 cimetidine, and patients in group 6 received 1.25 mg kg-1 ranitidine. Induction of anesthesia was supplemented by 0.002 mg kg-1 fentanyl and 0.01 mg kg-1 lormetazepam. After beginning neuromuscular monitoring, 0.08 mg kg-1 vecuronium was injected and the intubation accomplished when the first twitch of the train of four (TOF) was suppressed of a rate greater than 90%. The anesthesia was maintained with supplemental doses of 0.002 mg kg-1 fentanyl and 0.01 mg kg-1 lormetazepam, if necessary, and the use of a nitrous oxide/oxygen mixture (2.4:1.6 l min-1). A train of four supramaximal nerve stimuli was applied to the ulnar nerve proximal to the wrist and the twitch responses were electrically recorded on the hypothenar musculature (Relaxograph, Datex). The frequency of the train was 2 Hz with an interval of 20 s between trains. The time from the injection of vecuronium to several degrees of neuromuscular recovery was statistically significantly prolonged after 5 mg kg-1 cimetidine (groups 3 and 5) in comparison to the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)