HISTAMINE-RELEASE HEMODYNAMIC-CHANGES PRODUCED BY ROCURONIUM, VECURONIUM, MIVACURIUM, ATRACURIUM AND TUBOCURARINE

We have examined the effects of different benzyl-isoquinolinium and st eroidal neuromuscular blocking compounds on plasma concentrations of h istamine, heart rate and arterial pressure in surgical patients. A sin gle, rapid (5-s) bolus of mivacurium 0.2 mg kg(-1), atracurium 0.6 mg kg(-1), tubocurarine 0.5 mg kg(-1), vecuronium 0.1 mg kg(-1) or rocuro nium 0.6 mg kg(-1) was administered to 75 patients (n = 15 in each gro up). Anaesthesia was induced with thiopentone 6 mg kg(-1) i.v. and mai ntained with isoflurane and 70% nitrous oxide in oxygen. Venous blood samples were obtained before induction, 1 min after thiopentone and 1, 3 and 5 min after administration of the neuromuscular blocking drug. Mivacurium, atracurium and tubocurarine caused 370%, 234% and 252% inc reases in plasma histamine concentrations at 1 min, respectively. Corr esponding values at 3 min were 223%, 148% and 157%, respectively. Thes e changes were significant (P < 0.01) at 1 and 3 min. In contrast, the rocuronium and vecuronium groups had no significant changes in either plasma histamine concentrations or haemodynamic variables.