4-Aminopyridine in the Treatment of Patients With Multiple Sclerosis

OBJECTIVE: To study the long-term efficacy and safety of 4-aminopyridine in patients with multiple sclerosis. DESIGN: Case series, follow-up varying from 6 to 32 months. SETTING: University referral center. PATIENTS: Thirty-one patients with definite MS, 23 of them being exposed to long-term administration (6 to 32 months) of 4-aminopyridine, since they showed a favorable initial response to the drug. INTERVENTIONS: Long-term oral treatment with 4-aminopyridine in daily doses of up to 0.5 mg/kg of body weight. MAIN OUTCOME MEASURES: Neurologic functions and symptoms as reported by the patients; side effects. RESULTS: Twenty of 23 patients who showed a favorable initial response benefited from long-term administration. Ambulation and fatigue (each in 13 patients) and visual function (in five patients) were most frequently reported to be improved. Three major side effects did occur during a follow-up of 406 patient months: a generalized epileptic seizure in two patients and hepatitis in one. CONCLUSIONS: Although a substantial proportion of patients with multiple sclerosis seem to benefit from long-term administration of 4-aminopyridine, additional studies are needed to clarify the exact value of the drug.