Are granisetron and ondansetron equivalent in the clinic?

There are no published direct trials of granisetron vs. ondansetron. Difficulties exist in comparing reported trials because of differences in methodology, especially in response criteria. In this review, a comparison is made between ondansetron and granisetron by recalculating the complete response criterion for granisetron, standardising it against that in the ondansetron programme (i.e. no vomiting). Weighted means have been calculated for three areas of study. Against cisplatin-induced emesis the (weighted) mean percentage of complete responders were calculated at 64% (range 49-77%) for granisetron and 49% (range 40-55%) for ondansetron. Against moderately emetogenic stimuli, the response rates were 76% (range 68-80%) and 73% (range 60-87%) respectively. For fractionated chemotherapy the response rates were 57% and 27% for granisetron and ondansetron respectively. Although not shown by formal statistical analysis, these results suggest that a clinical advantage for granisetron may exist.