A double-blind, placebo-controlled trial of amantadine for the treatment of fatigue in patients with the post-polio syndrome.

Because amantadine has been shown to reduce fatigue in patients with multiple sclerosis, we performed a double-blind, placebo-controlled study to assess its efficacy in the disabling symptom of post-polio fatigue. Twenty-three patients completed six weeks of therapy. Fatigue was measured by the patients using visual analogue scales (twice per day) and numerical fatigue severity scales (once per week) and by overall impression (at end of therapy). Formal neuropsychological testing and serum drug levels were performed to assess compliance. On all measures, no significant difference was found between treatment and placebo groups. Fifty-four percent of patients given amantadine and 43% given placebo reported a decrease in fatigue; however, the visual analogue scales and fatigue severity scales failed to reflect any improvement. Several patients in the treatment group elected to continue amantadine therapy after the study was completed. Our findings suggest that amantadine is not significantly better than placebo in reducing the sensation of fatigue in post-polio syndrome, and that the measures we employed were insensitive to capture the subjective response experienced by a few patients.