Tropisetron - An update of its use in the prevention of chemotherapy-induced nausea and vomiting

Tropisetron is a serotonin (5-hydroxytryptamine; 5-HT) antagonist that is p rimarily used in the prevention of chemotherapy-induced nausea and vomiting . Antagonism of 5-HT3 binding sites in the peripheral and central nervous s ystem is the probable mechanism of prevention of acute nausea and vomiting. Effects on delayed nausea and vomiting are less well understood as these a re probably not mediated solely by 5-HT3 receptors. Tropisetron monotherapy is effective for the control of acute, and to a les ser extent delayed, nausea and vomiting in patients receiving moderately to severely emetogenic chemotherapy. The combination of dexamethasone and tro pisetron is more effective than monotherapy. Complete control of cisplatin- induced nausea and vomiting was obtained in 69 to 97% of patients receiving the combination compared with 46 to 80% receiving tropisetron monotherapy in randomised trials. There were generally no significant differences between the control of acut e or delayed nausea and vomiting provided by tropisetron, ondansetron or gr anisetron in randomised, comparative trials. The antiemetic efficacy of tro pisetron was maintained over multiple cycles of chemotherapy. Most comparative studies showed tropisetron monotherapy to be more effectiv e than metoclopramide in controlling acute nausea and vomiting, with the ex ception of 1 study which showed similar efficacy. However, high dose metocl opramide plus dexamethasone provided similar control of delayed emesis to t ropisetron plus dexamethasone. Tropisetron is also effective in children, including those who responded po orly to previous antiemetic treatment. Tropisetron and ondansetron generall y have similar efficacies in this population. The drug enhanced patients' quality of life and was well tolerated by adult s and children alike. The recommended oral and IV dosage of tropisetron is 5mg once daily; there is no increase in efficacy with doses >5mg. Conclusions: Tropisetron is similar to other 5-HT3 receptor antagonists for the prevention of chemotherapy-induced nausea and vomiting in both adults and children. It is suitable as first-line therapy (combined with a cortico steroid) for the prevention of acute nausea and vomiting in patients treate d with moderately to severely emetogenic chemotherapeutic agents. This comb ination is also moderately effective in the prevention of delayed nausea an d vomiting.