Ondansetron versus metoclopramide, both combined with dexamethasone, in the prevention of cisplatin-induced delayed emesis. The Italian Group for Antiemetic Research.

PURPOSE: The role of 5-HT3 receptor antagonists in the prevention of chemotherapy-induced delayed emesis is controversial. We compared ondansetron and metoclopramide, both combined with dexamethasone, in cisplatin-treated patients.

PATIENTS AND METHODS: Three hundred twenty-two patients who had been given > or = 50 mg/m2 of cisplatin were randomly assigned to receive, from days 2 to 4 after chemotherapy, oral ondansetron (8 mg twice daily) or oral metoclopramide (20 mg every 6 hours), both associated with intramuscular dexamethasone (8 mg twice on days 2 and 3, and 4 mg twice on day 4). Patients received the same intravenous prophylaxis for acute emesis: ondansetron 8 mg and dexamethasone 20 mg. Nausea and vomiting were assessed daily until day 6 after chemotherapy.

RESULTS: According to the intention-to-treat principle, 318 patients were assessable. Known prognostic factors were similar in the two treatment groups. Complete protection from delayed vomiting and nausea was achieved by 62.0% and 43.7% of patients treated with ondansetron and by 60.0% and 53.7% of those receiving metoclopramide (no significant differences). Patients who vomited in the first 24 hours achieved the lowest complete protection from delayed emesis. In these patients, ondansetron offered better complete protection from vomiting than metoclopramide (28.6% v 3.8%, P < .05). Both treatments were well tolerated.

CONCLUSION: The two treatments offer similar protection from delayed emesis, although ondansetron plus dexamethasone may be preferred in patients who suffer from acute vomiting. Optimal control of acute emesis is essential to achieve good protection from delayed nausea and vomiting, irrespective of the antiemetic treatment received.