A Cochrane review [withdrawn from publication] included 16 RCTs with a total of 7 808 cancer patients. In all trials cisplatin, being highly emetogenic, was used as chemotherapy, in 9 of them granisetron was compared with ondansetron. No other drug comparison was studied in more than one trial. The meta-analyses of the granisetron vs ondansetron trials found similar results for the two drugs on acute vomiting (OR 0.89; 95% CI 0.78 to 1.02; 8 trials, 4256 participants), acute nausea (OR 0.97; 95% CI 0.85 to 1.10; 7 trials, 4160 participants), delayed vomiting (OR 1.00; 95% CI 0.74 to 1.34; 3 trials, 1119 participants) and delayed nausea (OR 0.96; 95% CI 0.75 to 1.24; two trials, 1024 participants). Granisetron and ondansetron showed similar effects on headache and diarrhoea, with the possible exception of less constipation associated with ondansetron. One study of 1114 participants comparing palonosetron plus dexamethasone versus granisetron plus dexamethasone showed superiority of palonosetron in controlling delayed vomiting (OR 1.45; 95% CI 1.14 to 1.85) and delayed nausea (OR 1.63; 95% CI 1.27 to 2.10). Complete response for delayed nausea and vomiting was also in favour of the combination palonosetron and dexamethasone (OR 1.63; 95% CI 1.29 to 2.07).
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment.