The comparative value of amantadine and levodopa

Sixty-nine patients with Parkinson's disease were randomly allocated in a trial to compare the therapeutic effects of levodopa and amantadine. The patients were assessed clinically and scored by occupational therapy tasks and degrees of disability. Both drugs were used for 2 months; in the first 4 weeks the doses were gradually increased to 400 mg of amantadine or 4 g of levodopa respectively, and in the second 4 weeks' period the maximum tolerated dose was maintained throughout. Fourteen patients withdrew and these were excluded from the series. Of the fifty-five patients who completed the trial, thirty-four were taking levodopa and twenty-one amantadine.

The results showed an average 33% improvement on levodopa and 23% on amantadine as regards tremor, rigidity and akinesia and their total scores improved 26% and 18% respectively. More cases showed substantial improvement on levodopa.

There was little difference in response between 200 and 400 mg amantadine daily, but side-effects with 400 mg amantadine daily were more frequent and severe. Side-effects with levodopa were similar to those reported in previous trials but we also noted brown body fluids in three patients. The average effective dose of levodopa was lower than in previous reports, and the largest number of patients received benefit from 1·5 g daily. The superior effect of levodopa was shown.