Dolasetron is the free base of dolasetron mesylate [D5481] which is a selective serotonin subtype 3 (5-HT₃) receptor antagonist. It is rapidly converted in vivo to its active major metabolite, hydrodolasetron, which appears to be largely responsible for its pharmacological activity. 5-HT₃ receptors are located peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone (CTZ) of the area postrema, known as the emetic center of the brain. Therefore, selective 5-HT₃ receptor antagonists, dolasetron, granisetron [G0401], ondansetron [O0407] and tropisetron [T2743] are used for the prevention of chemotherapy-induced nausea and vomiting, but they have been reported to be associated with QTc prolongation. (The product is for research purpose only.)