ANTAGONISM OF ALCURONIUM WITH EDROPHONIUM OR NEOSTIGMINE

The reversal of slcuronium by edrophonium 1 mgkg"1 or neostigmine 35.7figkg~l was compered in 23 patients undergoing elective ophthalmic sorcery. Neuromuscular transmission was assessed by measuring the force of contraction of the adductor pollkis muscle in response to train-of-four supramaximal stimuli (2 Hz, 0.2 ms duration) delivered via surface electrodes to the ulnar nerve every 10 s. Anaesthesia was induced and maintained with Althesin, and patient * were ventilated to oormocarbia with 67 % nitrous oxide in oxygen. Neuromuscular blockade was induced with alcuronium 0.2-0.3 mgkg"1 and antagoniimi was attempted when the train-of-four ratio had recovered spontaneously to 0.1. Recovery of the first contraction response of the train-of-four and of fade were more rapid after edrophonium. Although most patients were monitored for at least 30min no re-curarization was seen. Comparison of the relative rates of recovery of the first contraction, and the response to train-of-four stimuli, suggests that edrophonium has a greater prejunctional effect than neostigmine. Despite the frequent use of alcuronium, the ant-agonism of neuromuscular blockade produced by this agent has not been examined fully. Although neostigmine remains the most popular anticholines-terase, recent studies demonstrating the efficacy of large doses of edrophonium (Bevan, 1979; Kopman, 1979) have prompted a revival of interest in its pharmacological actions (Foldes et al., 1981; Morri