Amantadine in Parkinson's disease. A double-blind, placebo-controlled, crossover study with long-term follow-up.

A double-blind, placebo-controlled, crossover study with long-term follow-up of amantadien i- Parkinson's disease was performed on 26 patients. Other antiparkinsonian medications were discontinued in all but three patients. Amantadine resulted in a statistically significant 12 percent overall improvement over placebo. Twenty of 26 patients, without breaking the code, selected amantadine for long-term usage. Ten patients continued treatment for 10 to 12 months, and an overall statistically significant improvement was noted at 2 weeks and at 1, 2, 3, and 10 to 12 months. Improvements in tremor and rigidity remained relatively constant, while there was some apparent loss of efficacy in timed tests and quality of timed tests. Amantadine appears effective in the long-term treatment of some patients with Parkinson's disease.