Ondansetron for nausea and vomiting associated with moderately emetogenic cancer chemotherapy.

This multicenter, randomized, double-blind study compared the efficacy and tolerability of ondansetron 8 mg twice daily for 3 days with placebo in preventing nausea and vomiting in 81 patients receiving cyclophosphamide-doxorubicin-based chemotherapy. The first dose of study drug was administered 30 minutes before the initiation of chemotherapy. Patients received a rescue antiemetic if the investigator deemed it necessary or if the patient experienced more than two emetic episodes during the 3-day study. Sixty-one percent of patients treated with ondansetron compared with 6% of patients receiving placebo (P < 0.001) had no emetic episodes during the 3-day study. Among patients with at least one emetic episode, the mean time to emesis was 24 hours 18 minutes in the ondansetron group compared with 8 hours 1 minute in the placebo group (P < 0.001). In the intent-to-treat analysis, 78% of patients in the ondansetron group and 29% of patients in the placebo group completed the study with no need for rescue therapy. Clinical laboratory and adverse-event profiles were similar between groups. The most common adverse event was headache, occurring in 23% of ondansetron patients and 24% of placebo patients. This study is the first double-blind, placebo-controlled trial to demonstrate that ondansetron 8 mg twice daily is effective in the prevention of nausea and vomiting associated with cyclophosphamide-doxorubicin-based chemotherapy. The twice-daily regimen may encourage patient compliance and may be more cost-effective than regimens that need to be given three times daily.