Prostigmine‐Induced Muscle Weakness in Myasthenia Gravis Patients

Abstract

Patients (4) with myasthenia gravis were given continuous infusions of prostigmine intravenously in an effort to determine the degree of maximum improvement which could be achieved by the drug and to determine the effects of maximally tolerable doses. The largest amount given, 10.0 mg in 1 hour, produced no improvement in a severely affected woman and may have made her worse. More definite weakness followed the administration of prostigmine to other patients after they had received, respectively, 10 mg in 2 5/6 hours, 8 mg in 2 3/4 hours and 20 mg in 3.5 hours. There was no consistent pattern of weakness and fasciculation was present in some patients but not in others. Recovery after prostigmine-induced weakness was rapid and there was suggestive, but inconclusive, evidence that weakness is produced at slower rates of infusion in patients whose disease is mild than in those whose symptoms are severe.