Neostigmine, Pyridostigmine, and Edrophonium as Antagonists of Pancuronium

This study was performed to compare the effects of three anticholinesterases on rates of recovery from pancuronium-induced neuromuscular blockade. Pancuronium (3 mg/70 kg) was antagonized during nitrous oxide-oxygen-halothane anesthesia, in man, with neostigmine (2.5 or 5.0 mg/70 kg), pyridostigmine (10 or 20 mg/70 kg), or edrophonium (50 or 100 mg/70 kg). Reversal was attempted at 10 per cent spontaneous recovery of muscle twitch, which was measured by use of train-of-four stimulation. Following administration of the antagonists each patient had progressive recovery of neuromuscular function. Recurarization was not observed during the period of study. Recovery was most rapid with edrophonium and slowest with pyridostigmine. Five minutes after administration of the antagonists, mean T4, the height of the fourth twitch as a percentage of the first in each train, exceeded 50 per cent only with the larger dose of neostigmine and both doses of edrophonium. Thirty minutes after reversal there was no significant difference in recoveries among the drugs tested, and T4 exceeded 70 per cent for all patients. It is concluded that, under the conditions of this study, neostigmine, pyridostigmine, and edrophonium induce sustained antagonism of pancuronium-induced neuromuscular blockade. The antagonism produced by large doses of edrophonium is faster than that produced by neostigmine or pyridostigmine.