ANTAGONISM OF VERCURONIUM-INDUCED NEUROMUSCULAR BLOCKADE WITH EDROPHONIUM OR NEOSTIGMINE

Antagonism of vecuronium-induced neuromuscular blockade wasattempted, at varying degrees of spontaneous recovery, withedrophonium 0.5 mg kg ^–1 or neostigmine 0.05 mg kg^–1in two groups of 20 patients. Neuromuscular blockade was monitoredusing a train-of-four (TOF) stimulation. Adequate antagonismof neuromuscular blockade, defined as a sustained TOF ratioof 0.7 or more, was attained in all 20 patients given neostigmineand in 13 out of 20 given edrophonium. Five of the remainingseven patients given edrophonium had shown three or less responsesto TOF stimulation before antagonism. While the time to onsetof the action of edrophonium (22 s) was not significantly shorterthan neostigmine (26 s), the time taken to attain a TOF ratioof 0.7 was significantly shorter with edrophonium (67 s comparedwith 194 s with neostigmine). It is concluded that edrophonium0.5 mg kg^–1 does not consistently antagonize vecuronium-inducedneuromusocular blockade, particularly if there are three orless responses to a TOF stimulation present before antagonism.