Ondansetron

5-HT3 Receptor Antagonist (Antiemetic)

Drug Class: 5-HT3 Receptor Antagonist (Antiemetic)
Mechanism of Action (MOA): Blocks serotonin 5-HT3 receptors centrally (chemoreceptor trigger zone) and in the gut → antiemetic.
Clinical Notes: Chemo, post-op, and gastroenteritis nausea. QT prolongation (check ECG/electrolytes); constipation and headache.
Source: FDA label

Sources

Reviewed June 2026

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