Double-blind controlled study of central nervous system side effects of amantadine, rimantadine, and chlorpheniramine.

A total of 52 healthy, adult volunteers were randomly assigned to five treatment groups to be treated twice daily for 4 days with 100 mg of amantadine, 100 mg of rimantadine, 4 mg of chlorpheniramine or placebo alone, or 100 mg of amantadine in combination with chlorpheniramine. The results of tests measuring performance on tasks of attention, reasoning, and memory were unaffected by treatment. Subjective side effects in recipients of amantadine, rimantadine, and chlorpheniramine were comparable and minimal. Side effects appeared to be enhanced in subjects receiving both amantadine and chlorpheniramine.