Treatment with oral 4-aminopyridine in disorders of neuromuscular transmission.

Four patients with Eaton-Lambert syndrome, four patients with congenital myasthenia, and one patient with myasthenia gravis were treated with oral 4-aminopyridine for periods of up to 10 months, doses varying from 40 to 200 mg per day. Clinical and electrophysiologic assessment confirmed the effectiveness of the drug when given alone or in conjunction with anticholinesterases. At therapeutically effective doses, central side effects were frequent and unpredictable. Three patients had a generalized fit and one patient developed a confusional state. Adverse side effects must severely limit the place of 4-aminopyridine in the treatment of patients with these conditions.