Prevention of histamine-induced cardiovascular reactions during the induction of anaesthesia following premedication with H1- + H2-antagonists i.m.

In a prospective controlled double-blind study, 60 elective surgical patients were randomly assigned to three premedication groups. Twenty patients received promethazine 0.5 mg kg-1 i.m. 45 min before induction of anaesthesia; a further 20 patients received an additional i.m. injection of cimetidine 400 mg 120 min before induction. The third group (n = 20) served as the control group. Following vecuronium 0.02 mg kg-1, anaesthesia was induced with fentanyl, and etomidate. All patients then received suxamethonium 1.5 mg kg-1 i.v. The combined administration of H1- + H2-antagonists as premedication led to a significant reduction in the increase in heart rate when compared with the effects in the other groups.