Changes in the plasma histamine concentration after the administration of vecuronium bromide

Clinical symptoms of anaphylactoid reaction to muscle relaxants vary from localized flush to cardiovascular collapse. Vecuronium bromide is reported to have very little histamine releasing property. However, there are some reports of anaphylaxis or anaphylactoid reaction to vecuronium. We studied plasma histamine concentration after the intravenous injection of vecuronium to confirm the histamine release. Twenty patients were randomly allocated to one of two groups, each group comprising of 10 patients: one group was to receive vecuronium 0.1 mg.kg(-1) and the other 0.2 mg.kg(-1) using the priming principle. Blood samples were taken prior to and 1, 3, 5, 8 and 13 min after the administration of vecuronium. The plasma histamine concentration was measured by radioimmunoassay with monoclonal antibody. There were no significant changes in plasma histamine concentration over 13 min after the administration of vecuronium compared with the baseline value. There were also no significant differences between these two groups. We concluded that vecuronium up to 0.2 mg.kg(-1) did not change the plasma histamine concentration in the patients having no previous history of allergy or atopic tendencies.