Ondansetron in the prophylaxis of acute cisplatin-induced nausea and vomiting.

Nausea and vomiting occur in all patients following high-dose cisplatin chemotherapy, unless an effective anti-emetic is administered. Early clinical studies therefore examined ondansetron treatment to establish an optimal dosing schedule for acute emesis. Pilot studies suggested that a daily dose of 32 mg ondansetron, given as a continuous intravenous infusion or intermittently on a mg/kg basis, gives optimum control of emesis, and was therefore selected for comparative studies. Efficacy was confirmed in two randomised, double-blind, crossover studies comparing ondansetron and metoclopramide. Ondansetron was superior to high-dose metoclopramide in controlling acute emesis and nausea, and there was a significant patient preference for ondansetron. These effects may be related to ondansetron's greater potency as a competitive 5-HT3 antagonist. In addition, ondansetron did not induce any extrapyramidal reactions, confirming the absence of any dopamine antagonist activity.