Small molecule
PubChem CID 4595
Ondansetron
Zofran
- Mechanism of action
- 5-HT3 receptor antagonist
- In plain language
- Blocks a chemical signal in the gut and brain that triggers nausea and vomiting.
- How it works
- Ondansetron is a selective antagonist at 5-HT3 (serotonin type 3) receptors, located both peripherally on vagal afferent nerve terminals in the small intestine and centrally in the chemoreceptor trigger zone of the area postrema. Emetogenic stimuli such as chemotherapy or radiotherapy cause enterochromaffin cells in the small intestine to release serotonin, which activates 5-HT3 receptors on vagal afferents and initiates the vomiting reflex via afferent signaling to the brainstem. By blocking these receptors, ondansetron interrupts this signaling cascade before it triggers emesis.
- Therapeutic applications
- FDA-indicated for the prevention of nausea and vomiting associated with highly and moderately emetogenic cancer chemotherapy, radiotherapy including total body irradiation, and postoperative nausea and vomiting.
- Class
- Small molecule
- Therapeutic area
- Gastrointestinal / Antiemetic
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