Increased gastric motility during 5-HT4 agonist therapy reduces response fluctuations in Parkinson's disease.

We investigated the clinical efficacy and tolerability of 45 mg/day mosapride, a selective 5-hydroxytryptamine type 4 (5-HT4) agonist, in an open-label study involving five patients with Parkinson's disease (PD) who had response fluctuations (RFs). 'On' time and motor function scores were determined, and gastric motility was measured by a radionuclide gastric emptying (GE) test, the most reliable quantitative method available. We found that mosapride therapy significantly shortened GE half-time, reduced RFs, and improved motor functions in all patients. There were no adverse reactions. We conclude that selective 5-HT4 agonist therapy is beneficial for patients with PD who have RFs.