[The effect of succinylcholine on vecuronium and pancuronium]

In 105 adult patients under halothane anesthesia, the neuromuscular blocking effects of vecuronium and pancuronium were determined with prior succinylcholine 1 mg.kg-1 administration and without. Force of the evoked twitch increased 123.7% of control after recovery from succinylcholine-induced block. Prior administration of succinylcholine was associated with a leftward shift of dose-response curve of vecuronium or pancuronium. Onset of the force reduction from initial dose (0.08 mg.kg-1) was faster and recovery from initial and maintenance doses (0.02 mg.kg-1) were slower. This potentiating effect persisted at least 2 hours.