Progress in reducing nausea and emesis. Comparisons of ondansetron (zofran), granisetron (kytril), and tropisetron (navoban)

BACKGROUND: Nausea and vomiting are the most distressing side effects associated with the administration of chemotherapy for neoplastic diseases. Nausea, in particular, often had been ignored in studies of chemotherapy side effects. Recently, progress has been made in the control of chemotherapy-induced nausea and vomiting, due, in part, to a better understanding of the physiologic mechanisms involved. METHODS: This paper reviews recent advances in the control of emesis, focusing on pharmacologic treatments. RESULTS: The efficacy and safety of the serotonin (5-HT3) receptor antagonists granisetron, ondansetron, and tropisetron in the control of acute and delayed emesis and emesis induced by repeat-cycle chemotherapy are summarized. Although differences in study design and definitions of response criteria have made it difficult to compare the studies that have evaluated these three agents, the overall body of literature supports several clinical findings. CONCLUSIONS: (1) The 5HT3 antiemetic agents have been shown to be clinically more effective in the control of nausea and emesis than previously used agents. (2) No one of the three has demonstrated consistently greater efficacy. (3) Efficacy appears to be more pronounced for cisplatin-containing regimens than for moderate or less emetogenic chemotherapy regimens. (4) Effectiveness of the 5HT3 agents appears to be less for delayed nausea and emesis than for acute symptoms. Potential control of anticipatory nausea and emesis has not been investigated. (5) Control over nausea appears to be significantly less than control over emesis. In the studies in which it has been measured, nausea control remains incomplete for approximately half the patients given 5HT3 agents. (6) The efficacy of the agents appears to diminish across repeated days and, perhaps, across repeated chemotherapy cycles. (7) The addition of a steroid such as dexamethasone increases the efficacy of both 5HT3 and other antiemetic agents. This effect also seems to apply to delayed nausea and emesis.