COMPARATIVE EFFECTS OF PIPECURONIUM AND TUBOCURARINE ON PLASMA CONCENTRATIONS OF HISTAMINE IN HUMANS

We have examined the effects of a rapid bolus dose of pipecuronium0.1 mg kg^–1 or tubo-curarine 0.5mg kg^–1 on plasmahistamine concentration, heart rate and arterial pressure in20 patients (n = 10 in each group). Anaesthesia was inducedwith thiopentone 6 mg kg^–1 i.v. and maintained with 70%nitrous oxide and halo-thane in oxygen. Neuromuscular blockingdrugs were administered 4 min after administration of thiopentone.Venous blood samples were obtained before induction, 1 min afterthiopentone and 1, 3 and 5 min after the administration of theneuromuscular blocking drugs. Tubocurarine caused 240% and 210%increases in plasma concentration of histamine at 1 and 3 min,respectively. These changes were significant (P < 0.05) at1 min and associated with a decrease in mean arterial pressureand an increase in heart rate. None of the 10 patients receivingpipecuronium had a significant change in plasma concentrationof histamine or in haemo-dynami variables. ^*Present addresses: Department of Anaesthesia, Al-Kasr El-AniHospital, Cairo University, Cairo, Egypt. Present addresses: Department of Pharmacology, Lund University,Lund, Sweden.