Potentiation of pancuronium and vecuronium neuromuscular blockade by intravenous salbutamol.

Three doses of salbutamol 125 micrograms iv were given, over 3.5 hr, to a 28-yr-old healthy, previously non-asthmatic man during thiopentone-O2/N2O-isoflurane anaesthesia for treatment and prophylaxis of bronchospasm. Force of contraction of the adductor pollicis was measured before and after the last two injections. Initially, the patient was given pancuronium, 5 mg. Salbutamol, 125 micrograms iv, was given when T1 blockade was 45%. Blockade increased to 66% over five minutes and returned to 45% after 18 min. Vecuronium was subsequently used to maintain relaxation. At the end of surgery, salbutamol was followed by an increase in T1 blockade, from 66% to 86%, over five minutes which returned to 66% after ten minutes. It is concluded that intravenous salbutamol potentiates the neuromuscular blocking effect of nondepolarizing muscle relaxants.