ATC Group: A04AA Serotonin (5HT3) antagonists

Dolasetron and its active metabolite, hydrodolasetron (MDL 74,156), are selective serotonin 5-HT₃ receptor antagonists not shown to have activity at other known serotonin receptors and with low affinity for dopamine receptors. The serotonin 5-HT₃ receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema.

Granisetron is a potent anti-emetic and highly selective antagonist of 5-hydroxytryptamine (5HT₃ receptors). Pharmacological studies have demonstrated that granisetron is effective against nausea and vomiting as a result of cytostatic therapy.

Netupitant is a selective antagonist of human substance P/neurokinin 1 (NK₁) receptors. Delayed emesis has been associated with the activation of tachykinin family neurokinin 1 (NK₁) receptors (broadly distributed in the central and peripheral nervous systems) by substance P. As shown in in vitro and in vivo studies, netupitant inhibits substance P mediated responses.

Ondansetron is a potent, highly selective 5HT₃ receptor-antagonist. Its precise mode of action in the control of nausea and vomiting is not known.

Palonosetron is a selective high-affinity receptor antagonist of the 5HT₃ receptor.

Tropisetron is a highly potent and selective competitive antagonist of the 5-HT₃ receptor. Tropisetron selectively blocks the excitation of the presynaptic 5-HT₃ receptors of the peripheral neurons in this reflex, and may exert additional direct actions within the CNS on 5-HT₃ receptors mediating the actions of vagal input to the area postrema.