Comparative trials of ondansetron versus metoclopramide in the prevention of acute cisplatin-induced emesis.

A logical outgrowth of the early clinical success with ondansetron in phase I and phase II trials has been an interest in comparative antiemetic trials using conventional agents. Metoclopramide is generally acknowledged to be the single most effective conventional drug for the prevention of acute cisplatin-induced emesis and, therefore, was considered an appropriate agent for inclusion in comparative trials with ondansetron. Three phase III trials comparing metoclopramide with ondansetron for the prevention of acute nausea and vomiting associated with cisplatin administration have been completed to date. One was a single-blind, parallel-group trial conducted in the United States, and the other two were double-blind, crossover trials performed in Europe. The efficacy results of these studies demonstrated either a consistent trend or clear superiority of ondansetron in comparison with metoclopramide. Treatment failure consistently developed much later with ondansetron than with metoclopramide. Less antiemetic toxicity was noted with ondansetron. With the exception of headache, there was a lower incidence of neurologic adverse events in the ondansetron group. No dystonic reactions were observed with ondansetron in any of the trials. In all three trials, patients expressed greater overall satisfaction with ondansetron for emesis control.