A Randomized Controlled Trial of Amantadine in Fatigue Associated With Multiple Sclerosis

One hundred and fifteen patients with definite multiple sclerosis (M.S.) and chronic persistent fatigue were studied. This ten-week cross-over study consisted of a 2-week baseline period and two 3-week treatment periods separated by a 2-week washout. Patients received either amantadine 100 mg bid or matching placebo capsules. Fatigue, the effect of fatigue on an individually pre-selected activity and its effect on activities of daily living, were evaluated. Amantadine produced a small but statistically significant decrease in fatigue. An important placebo effect was noted. Mean fatigue during the washout period was lower than during the placebo run-in period, independently of which treatment had been given first. Side effects were numerous both on amantadine and on placebo. Only insomnia was significantly more common with amantadine.