Effect of ritanserin, a highly selective 5-HT2 receptor antagonist, on Parkinson's disease.

There is both experimental and clinical evidence to suggest a role for 5-hydroxytryptamine (5-HT) in Parkinson's disease. The effect of ritanserin, a highly selective 5-HT2 receptor antagonist, on Parkinsonian symptomatology was investigated in 10 patients in a single-blind placebo-controlled study. Akinesia and gait improved significantly in a dose-dependent manner in 5 and 7 patients respectively. However there was no significant improvement in tremor. The effects of ritanserin on akinesia and gait are consistent with a role for 5-HT in Parkinson's disease.