The 5-HT receptors (5-hydroxytryptamine, or serotonin) is a cation-selective ion channel that mediates neuronal depolarization and excitation within the central and peripheral nervous systems.
When the receptor is activated to open the ion channel by agonists, the following effects are observed:
- CNS: nausea and vomiting center in brain stem, anxiety, seizure propensity
- PNS: neuronal excitation (in autonomic, nociceptive neurons), emesis

The 5-HT3 antagonists are informally known as "setrons"
5-HT3 antagonists are most effective in the prevention and treatment of chemotherapy-induced nausea and vomiting, especially that caused by highly emetogenic drugs, such as cisplatin; when used for this purpose, they may be given alone or, more frequently, with a glucocorticoid, usually dexamethasone. They are usually given intravenously, shortly before administration of the chemotherapeutic agent, although some authors have argued that oral administration may be preferred.
The concomitant administration of a NK1 receptor antagonist, such as aprepitant, significantly increases the efficacy of 5-HT3 antagonists in preventing both acute and delayed chemotherapy-induced nausea and vomiting.

The 5-HT3 antagonists are also indicated in the prevention and treatment of radiation-induced nausea and vomiting, and postoperative nausea and vomiting.
Current evidence suggests that 5-HT3 antagonists are ineffective in controlling motion sickness.

Available agents.
- Ondansetron
- Tropisetron
- Granisetron
- Dolasetron
- Palonosetron
- Ramosetron

See reference for more information.

Adapted from Wikipedia, the free encyclopedia. Internet. Accessed on October 25, 2016.