Comparison of ondansetron and ondansetron plus dexamethasone as antiemetic prophylaxis during cisplatin-containing chemotherapy.

Ondansetron, a serotonin antagonist, is effective in controlling the emesis associated with cancer chemotherapy; however, emesis in patients receiving high-dose cisplatin is poorly controlled by ondansetron alone. Dexamethasone is an effective antiemetic with no known interaction with serotonin receptors and was thus chosen for study in combination with ondansetron. 31 patients (30 male, 1 female; median age 28.5 years, range 18-49) receiving a 4-day course of a chemotherapy regimen containing cisplatin (100-120 mg/m2) for metastatic germ-cell tumours were entered in a randomised, double-blind, cross-over trial comparing oral ondansetron plus placebo with oral ondansetron plus dexamethasone as antiemetic prophylaxis. Ondansetron (8 mg every 8 h) was given to all patients for 8 days from the start of chemotherapy. Patients were given 8 mg of dexamethasone or placebo every 8 h starting 2 h before cisplatin (on day 4) and continuing for six doses (ie, for 2 days only). A second course of chemotherapy began 14 days after the start of the first, during which patients crossed over to the alternative antiemetic regimen. Results were available from 27 patients. In the 24-48 h after cisplatin 78% of patients taking ondansetron plus dexamethasone reported complete or major control of emesis compared with 30% of those taking ondansetron plus placebo (p = 0.001). Cross-over analysis showed a significant advantage for ondansetron plus dexamethasone in the control of nausea (p = 0.013) and emesis (p less than 0.001) over the 8-day study. 24 of 26 patients expressed a preference for the combination therapy (p less than 0.001). Ondansetron plus dexamethasone is effective antiemetic prophylaxis for high-dose cisplatin chemotherapy, has few side effects, and is active when given orally.