AN OPEN-LABELED CLINICAL AND ELECTROPHYSIOLOGICAL STUDY OF 3,4-DIAMINOPYRIDINE IN THE TREATMENT OF FATIGUE IN MULTIPLE-SCLEROSIS

We studied the electrophysiological parameters of motor performance in eight patients with multiple sclerosis and troublesome fatigue, befor e and after treatment with 3,4-diaminopyridine. Symptomatic fatigue wa s evaluated by the Krupp Fatigue Severity Score and motor performance of adductor pollicis by transcranial magnetic stimulation, rapid volun tary movements and a fatiguing exercise test of a sustained 45-s isome tric contraction. The motor tests revealed baseline abnormal motor fun ction and substantial central fatigue. After a 3-week course of 3,4-di aminopyridine (25-60 mg/day), six out of the eight patients reported s ubstantial improvement in fatigue and the group showed slightly less f atigue on the exercise test. Other electrophysiological tests of motor function were unchanged. The findings suggest that 3,4-diaminopyridin e may play a role in the symptomatic treatment of fatigue in multiple sclerosis. However, the mechanism behind such a benefit in fatigue rem ains unclear and the discrepancy between subjective and more objective responses underlines the probable multifactorial nature of the pathog enesis of this symptom in multiple sclerosis.