Antagonism of mivacurium block with edrophonium from various degrees of spontaneous recovery.

Seventy adult patients received mivacurium 0.15 mg kg-1 during anaesthesia with thiopentone, nitrous oxide and 0.5% halothane. Neuromuscular block was monitored using mechanomyography and train-of-four stimulation. Edrophonium 0.75 mg kg-1 was administered 5 or 10 min after mivacurium, or when the first response in the TOF (T1) had recovered to 5, 10, 25 or 50% of control in groups of 10 patients each. A control group was allowed to recover spontaneously. The mean time taken from administration of mivacurium to attaining a TOF ratio of 0.7 was between 19.3 and 24.9 min in the groups given edrophonium, regardless of the time of administration, compared with 26.7 min in the spontaneous recovery group. The differences, however, were not significant among the groups showing little advantage in antagonizing mivacurium block.