Antagonism of alcuronium with edrophonium or neostigmine

The reversal of alcuronium by edrophonium 1 mg kg-1 or neostigmine 35.7 micrograms kg-1 was compared in 23 patients undergoing elective ophthalmic surgery. Neuromuscular transmission was assessed by measuring the force of contraction of the adductor pollicis 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 patients were ventilated to normocarbia with 67% nitrous oxide in oxygen. Neuromuscular blockade was induced with alcuronium 0.2-0.3 mg kg-1 and antagonism 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 30 min 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.