An extended clinical trial to compare levodopa and amantadine used as single drugs with both drugs used in combination in Parkinson's Disease

Summary

AN extended clinical trial was carried out to evaluate the treatment of Parkinson's disease with levodopa and amantadine used as single drugs and in combination over a period of nine months. The initial improvement that occurred at 12 weeks on amantadine and combined therapy was maintained over the succeeding nine months. Further improvement was noted both with amantadine and combined treatment, but the amount of improvement was not at a significant level. The initial improvement which occurred at 12 weeks on levodopa was not maintained over the succeeding nine months though the deterioration which occurred was not at a significant level. A greater number of clinical side effects occurred with combined treatment than with single drug therapy, but biochemical tests for toxicity were normal throughout the trial. On the basis of the lack of any deterioration with amantadine and in view of the slight improvement noted with this drug, it is suggested that this drug is of benefit for the long-term treatment of Parkinson's disease in some cases. It could not be concluded that combined treatment was significantly more effective than single drug therapy. The deterioration noted with levodopa suggests that perhaps this drug does not alter the natural history of Parkinson's disease.