5-HT3 receptor antagonists

5-HT3 receptor antagonists block serotonin receptors in the gut and in the brain's vomiting center. Ondansetron prevents and treats nausea and vomiting from chemotherapy, surgery, and radiation. Headache and constipation are the most common side effects. They can prolong the QT interval, so caution is needed with other QT-prolonging drugs and with electrolyte imbalances.

• OndansetronKnown brand names include No current brand name; marketed as generic ondansetron tablets and injection (the original brand was Zofran).