Classification: FDA-approved Antiemetic ( anti-nausea )



  • Zofran is often used in patients with nausea caused by surgery, chemotherapy, migraines, pregnancy or vomiting caused by an illness.  


Mechanism of Action: 

  • Zofran (Ondansetron) works by blocking the actions of chemicals in the body that trigger nausea and vomiting
    • Zofran is a serotonin antagonist that blocks the serotonin 5-HT3 receptors in the chemoreceptor trigger zone (CTZ) within the medulla oblongata; the CTZ communicates with the vomiting center of our brain. Therefore, by blocking the amount of serotonin entering the CTZ, there is a decrease in communication and stimulation of the vomiting center, leading to decreased nausea and vomiting. 



  • The recommended adult intravenous dosage of Zofran is 0.15mg/kg up to a maximum of 16mg per dose. It is important to note that maximum dosages are reserved for patients undergoing chemotherapy or radiation treatments. Most post-operative nausea and vomiting as well as illness induced nausea is controlled with a dose of 4mg.
  • The recommended adult intramuscular dosage of Zofran is a single dose of 4mg injected into either gluteus maximus. 



  • Do not use if: 
    • Allergic to Ondansetron, Dolasetron (Anzemet), Granisetron (Kytril) or Palonosetron (Aloxi).
  • Tell your provider if you have a history of:
    • Congestive heart failure
    • Bradycardia (slow heart rate)
    • Personal or family history of long QT syndrome
    • Heart arrhythmias
    • Currently on any psychotropic medications 


Potential Side Effects: 

  • Diarrhea
  • Dizziness 
  • Drowsiness