Dexamethasone alone or in combination with ondansetron for the prevention of delayed nausea and vomiting induced by chemotherapy

Background: The prevention of delayed nausea and vomiting caused by moderately emetogenic chemotherapy for cancer has not been studied systematically. Methods: We enrolled patients who were scheduled to receive chemotherapy for the first time in a double-blind, randomized, multicenter study. All the patients received ondansetron combined with dexamethasone for prophylaxis against emesis that might occur within 24 hours after the start of chemotherapy (acute emesis). They were then divided into two groups: patients who did not have either vomiting or moderate-to-severe nausea (the low-risk group) and patients who had one or both (the high-risk group). Patients in the low-risk group were then randomly assigned to one of the following regimens, given on days 2 through 5 after the start of chemotherapy: oral placebo, 4 mg of dexamethasone given orally twice daily, or 8 mg of ondansetron in combination with 4 mg of dexamethasone, given orally twice daily. Patients in the high-risk group were randomly assigned to receive oral dexamethasone alone or in combination with ondansetron at the same doses as those used in the low-risk group. Results: Among the 618 patients in the low-risk group, there was a complete absence of both delayed vomiting and moderate-to-severe nausea in 91.8 percent of those who received ondansetron combined with dexamethasone, 87.4 percent of those who received dexamethasone alone, and 76.8 percent of those who received placebo. The proportions of patients who were protected by dexamethasone combined with ondansetron or by dexamethasone alone were significantly greater than the proportion protected by placebo (P<0.001 and P<0.02, respectively). Of the 87 patients in the high-risk group, complete protection was achieved in 40.9 percent of those treated with ondansetron and dexamethasone and in 23.3 percent treated with dexamethasone alone (P not significant). Conclusions: The best way to prevent delayed nausea and vomiting in patients receiving moderately emetogenic chemotherapy is to control these complications within the first 24 hours after the start of chemotherapy. Dexamethasone alone provides adequate protection against delayed emesis in patients at low risk (those who have not had acute emesis). (N Engl J Med 2000;342:1554-9.) (C) 2000, Massachusetts Medical Society.