Comparative effects of pipecuronium and tubocurarine on plasma concentrations of histamine in humans.

Abstract

We have examined the effects of a rapid bolus dose of pipecuronium 0.1 mg kg-1 or tubocurarine 0.5 mg kg-1 on plasma histamine concentration, heart rate and arterial pressure in 20 patients (n = 10 in each group). Anaesthesia was induced with thiopentone 6 mg kg-1 i.v. and maintained with 70% nitrous oxide and halothane in oxygen. Neuromuscular blocking drugs were administered 4 min after administration of thiopentone. Venous blood samples were obtained before induction, 1 min after thiopentone and 1, 3 and 5 min after the administration of the neuromuscular blocking drugs. Tubocurarine caused 240% and 210% increases in plasma concentration of histamine at 1 and 3 min, respectively. These changes were significant (P less than 0.05) at 1 min and associated with a decrease in mean arterial pressure and an increase in heart rate. None of the 10 patients receiving pipecuronium had a significant change in plasma concentration of histamine or in haemodynamic variables.