Atracurium in the myasthenic patient.

The use of the new competitive muscle relaxant, atracurium, is described in five myasthenic patients presenting for thymectomy. With an initial dose of 0.1 mg/kg, that is approximately one-fifth of that normally used, and incremental doses of 0.02-0.04 mg/kg, satisfactory clinical conditions were achieved. Neuromuscular function was monitored throughout using the train-of-four mechanical twitch response, and residual neuromuscular blockade was reversed satisfactorily at the end of the procedure with neostigmine 5.0 mg. A marked increase in the magnitude of the first twitch of the train-of-four to greater than control levels, accompanied by pronounced fade, was found on reversal. In reduced dosage and with careful neuromuscular monitoring, atracurium is safe to use in the myasthenic patient.