Summary

Ondansetron is a 5-HT3 Serotonin receptor antagonist, used to treat nausea and vomiting. As a drug modulating serotonin, serotonin syndrome is a potential adverse effect. Another important side effect is QT prolongation, which can result in Torsades de Pointes.

Key Points

• Ondansetron
  • Mechanism
    • Serotonin (5-HT3) antagonist
      • Acts in area postrema of medulla (vomiting centers)
        • Central-acting antiemetic
      • Also acts at peripheral and enteric nerves
        • Decrease vagal stimulation to GI tract
  • Clinical Use
    • Antiemetic
      • Especially in setting of GI-injury (e.g. postoperative, infection) or chemotherapy
  • Adverse Effects
    • Serotonin syndrome
      • Any drug that modulates serotonin signaling may lead to serotonin syndrome
    • QT interval prolongation
      • Risk for Torsades de Pointes
    • Headache
    • Constipation