Antagonism of vecuronium-induced neuromuscular blockade with edrophonium or neostigmine.

Antagonism of vecuronium-induced neuromuscular blockade was attempted, at varying degrees of spontaneous recovery, with edrophonium 0.5 mg kg-1 or neostigmine 0.05 mg kg-1 in two groups of 20 patients. Neuromuscular blockade was monitored using a train-of-four (TOF) stimulation. Adequate antagonism of neuromuscular blockade, defined as a sustained TOF ratio of 0.7 or more, was attained in all 20 patients given neostigmine and in 13 out of 20 given edrophonium. Five of the remaining seven patients given edrophonium had shown three or less responses to TOF stimulation before antagonism. While the time to onset of the action of edrophonium (22 s) was not significantly shorter than neostigmine (26 s), the time taken to attain a TOF ratio of 0.7 was significantly shorter with edrophonium (67 s compared with 194 s with neostigmine). It is concluded that edrophonium 0.5 mg kg-1 does not consistently antagonize vecuronium-induced neuromuscular blockade, particularly if there are three or less responses to a TOF stimulation present before antagonism.