[Pharmacological review of tropisetron]

Tropisetron is used as an anti-emetic agent against chemotherapy-induced nausea and vomiting. Tropisetron shows strong 5-HT3 antagonist and weak 5-HT4 antagonist activities in vitro. In the various animal models of vomiting including chemotherapy- or radiotherapy-induced emesis in the dog and ferret, tropisetron is reported to inhibit the emetic episodes. The potent anti-emetic activity of oral tropisetron rather than the i.p. administered drug suggests that it can act directly from the intestinal lumen as well as from the blood stream after its absorption. Moreover, the anti-emetic activity of tropisetron may involve the 5-HT4-receptor mechanism in addition to the 5-HT3-receptor mechanism. Tropisetron has several pharmacological activities other than anti-emesis such as the stimulation of the gastric emptying and the inhibition of the diarrhea, visceral pain and anxiety. These effects of tropisetron may contribute to the high clinical efficacy of tropisetron against chemotherapy-induced emesis.