Ondansetron  别名：SN 307; GR 38032F; GR-C507/75; 昂丹司琼

Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic. Its effects are thought to be on both peripheral and central nerves. Ondansetron decreases the activity of the vagus nerve, which deactivates the vomiting center in the medulla oblongata, and also inhibits serotonin receptors in the chemoreceptor trigger zone. Ondansetron has little effect on vomiting caused by motion sickness, and does not have any effect on dopamine receptors or muscarinic receptors. The 5-HT3 receptor antagonists are the primary drugs used to treat and prevent chemotherapy-induced nausea and vomiting (CINV). Ondansetron is also effective in controlling post-operative nausea and vomiting (PONV) and post-radiation nausea and vomiting, and is a possible therapy for nausea and vomiting due to acute or chronic medical illness or acute gastroenteritis. Although ondansetron is highly effective, the high cost of the brand-name version had limited its use to controlling PONV and CINV.Ondansetron is also used off-label to treat hyperemesis gravidarum in pregnant women, but there is no conclusive data available on its safety in pregnancy, especially during the first trimester. Ondansetron is also used to treat cyclic vomiting syndrome.