Drug Summary

Ondansetron Hydrochloride (Zofran®)

Pharmacologic properties:

Ondansetron hydrochloride is an anti-emetic which acts as a selective inhibitor of the serotonin 5-HT 3 receptor type. The drug binds to both central nervous system and peripheral receptors in the gastrointestinal tract to exert it’s effects. It’s onset of action is 30 minutes, and duration of action is 2-7 hours. Zofran is considered safe for use during pregnancy.


  • Severe, persistent vomiting


  • Known hypersensitivity
  • Known Long-QT Syndrome


  • May lengthen QT interval – patients should be placed on a cardiac monitor after administration
  • The use of ondansetron in patients following abdominal surgery may mask a progressive ileus and/or gastric distention

Adverse Reactions:

  • Headache
  • Fatigue
  • Diarrhea
  • Dizziness

Dosage and administration:

  • Adult:
    • 4 mg IV
    • 4 mg PO (Oral Disintegrating Tablet, ODT)
  • Infants and Children 6 months to 10 years, ≥8 kg (18 lbs)
    • 8-15 kg (18-33 lbs): 2 mg ODT, PO
    • >15 kg (>33 lbs): 4 mg ODT, PO