A double-blind crossover study comparing prophylactic intravenous granisetron alone or in combination with dexamethasone as antiemetic treatment in controlling nausea and vomiting associated with chemotherapy.

The efficacies of granisetron plus dexamethasone and granisetron alone in controlling nausea and vomiting during two consecutive cycles of moderately emetogenic chemotherapy given for up to 5 days were compared in a two-centre, randomised, double-blind, placebo-controlled crossover study. In all, 110 evaluable patients received either dexamethasone, 20 mg i.v., or matching placebo, plus open-label granisetron, 3 mg i.v., given on each chemotherapy day. At cycle 2, patients crossed over to the alternative treatment; 72 patients completed the crossover. In these 72 patients, the complete response rates over 24 h for granisetron plus dexamethasone and granisetron plus placebo in cycle 1 were 87% and 70% (ns), respectively. In cycle 2 the complete response rates over 24 h were 73% and 62% (ns). Combining the two cycles, the complete response rates over 24 h were 80.6% (granisetron plus dexamethasone) and 65.3% (granisetron plus placebo; P = 0.015). Granisetron plus dexamethasone was significantly more effective in terms of times to less than complete response (P = 0.041), to first episode of moderate/severe nausea (P = 0.04), to first episode of vomiting (0.03) and to use of rescue medication (P = 0.02). Adverse events tended to be minor, with asthenia and insomnia the most common. Of those patients who expressed a preference, 67% preferred granisetron plus dexamethasone (P < 0.05). A single dose of dexamethasone added to granisetron thus enhances the efficacy of granisetron alone in preventing nausea and vomiting after moderately emetogenic chemotherapy.