Effect of memantine (NMDA antagonist) on Parkinson's disease: A double-blind crossover randomized study

Our aim was to evaluate the effect of Memantine (1-amino 3,5-dimethyladaman tane hydrochloride) on cardinal symptoms of Parkinson's disease and on the latency, duration, and magnitude of the response to a single dose of L-Dopa and on drug-induced dyskinesias. Twelve Hoehn-Yahr III-IV patients with id iopathic Parkinson's disease with motor fluctuations and drug-induced dyski nesias were randomized to the NMDA antagonist memantine or placebo in a cro ss-over design. A single-dose L-Dopa challenge was performed after each med ication arm. A significant drug effect on the Unified Parkinson's Disease R ating Scale motor score was observed in "off" and "on" states (F(1,11)= 13. 5; p < 0.003). No significant effect on drug-induced dyskinesias was seen. The results suggest that memantine may improve parkinsonian symptoms indepe ndently of dopaminergic drugs and, in contrast to recent findings with aman tadine, it has no effect on drug-induced dyskinesias.