Ondansetron is a potent and highly selective 5HT3 – receptors antagonist.
It is indicated for the prevention and treatment of nausea and vomiting induced by cytotoxic chemotherapy ,radiotherapy and for the prevention and treatment of post-operative nausea and vomiting.
-Chemotherapeutic agents and radiotherapy may cause release of 5HT in the small intestine by activating the vagal afferents via 5HT3 – receptors. Ondansetron blocks the initiation of this reflex.