Zofran Side Effects: Adverse Patient Reactions to Ondansetron







Zofran Side Effects. Does Zofran (generic name: ondansetron) have side effects? Of course, all drugs have side effects. If your condition requires you to take in Zofran, you should be aware of the drug’s side effects.

Manufactured and marketed by GlaxoSmithKline, Zofran is a drug that prevents nausea and vomiting caused by cancer chemotherapy, radiation therapy, and surgery. Ondasetron is also being marketed by other drug companies under different trade/brand names such as: Zuplenz (Strativa Pharmaceuticals), Emeset (Cipla Ltd.), Emetron (Gedeon Richter Ltd.), Emodan (Korea United Pharmaceuticals), Ondemet(Zentiva a.s.), Setronax (Strides Arcolab), Ondansetron (Glenmark Generics Ltd. – India), and Ondavell (Novell Pharmaceutical Laboratories).

According to Medline Plus, the side effects of Zofran and the other ondansetron drugs include, diarrhea, headache, constipation, weakness, tiredness, and dizziness.

More serious side effects, which should be communicated to your doctor immediately, include the following: rashes, hives, itching, swelling of the eyes, face, lips, tongue, throat, hands, feet, ankles, or lower legs, hoarseness, difficulty breathing or swallowing, shortness of breath, and noisy high-pitched breathing.

In September 2011, the U.S. Food and Drug Administration (FDA) warned that it is conducting a safety review of Zofran and the other ondansetron drugs as they may cause fatal abnormal heart rhythms

Here’s part of the statement released by the agency:



The U.S. Food and Drug Administration (FDA) is informing the public of an ongoing safety review of the anti-nausea drug Zofran (ondansetron, ondansetron hydrochloride and their generics). Ondansetron may increase the risk of developing abnormal changes in the electrical activity of the heart, which can result in a potentially fatal abnormal heart rhythm.

According to the agency, the changes in the heart’s electrical activity can lead to an “abnormal and potentially fatal heart rhythm (including Torsade de Pointes)”. Especially at risk of developing Torsade include the following:

  • Patients with underlying heart conditions, such as congenital long QT syndrome
  • Those who are predisposed to low levels of potassium and magnesium in the blood and
  • Those taking other medications that lead to QT prolongation

Because of this risk, the agency has directed Zofran manufacturer GlaxoSmithKline to undertake an extensive research to study the “potential for the drug to prolong the QT interval”. The results of the study should be available next year.

Despite the added risk for those using the drug, patients should NOT stop taking Zofran (or the other brands) without first talking to their doctors. Here’s an additional information for patients from the FDA Media Release:

  • Do not stop taking Zofran (ondansetron) without talking to your healthcare professional.
  • Discuss any questions or concerns about Zofran (ondansetron) with your healthcare professional.
  • While taking Zofran (ondansetron), your healthcare professional may occasionally order an electrocardiogram (ECG, EKG) to monitor your heart rate and rhythm.
  • Seek immediate care if you experience an irregular heartbeat, shortness of breath, dizziness, or fainting while taking Zofran (ondansetron).
  • Report any side effects you experience to the FDA MedWatch program (phone: 1-800-332-1088 or 1-800-FDA-0178 (fax) or mail: MedWatch 5600 Fishers Lane Rockville, MD 20857

Information Sources:
Food and Drug Administration
Medline Plus (the information service of the United States National Library of Medicine (NLM).