Ondansetron/Possible QT Prolonging Agents Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Ondansetron can affect your heart's rhythm. Other drugs can have the same effect.

What might happen:

Taking ondansetron with other agents that can affect your heart rhythm may increase your risk of irregular heartbeat, which may be life-threatening.

What you should do about this interaction:

Make sure your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together and all other medicines you are taking. Your doctor may want to perform an electrocardiogram (ECG) on you to check your heart rate and rhythm. Let your doctor know right away if you notice and irregular heartbeat or have any dizziness or fainting episodes.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Kon P. Dear UK Healthcare Professional: Direct Healthcare Professional Communication on ondansetron (Zofran and generics) and dose-dependent QT interval prolongation - new dose restriction for intravenous (IV) use. GlaxoSmithKline UK Ltd August 5, 2012.
  • 2.Zofran (ondansetron) US prescribing information. GlaxoSmithKline March, 2017.
  • 3.USFood and Drug Administration. FDA Drug Safety Communication: Abnormal heart rhythms may be associated with use of Zofran (ondansetron). available at: http://www.fda.gov/Drugs/DrugSafety/ucm271913.htm September 15, 2011.
  • 4.Drew BJ, Ackerman MJ, Funk M, Gibler WB, Kligfield P, Menon V, Philippides GJ, Roden DM, Zareba W. Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation. J Am Coll Cardiol 2010 Mar 2;55(9):934-47.
  • 5.Health Canada. Zofran (ondansetron) - Dosage and Administration of Intravenous Ondansetron in Geriatrics (>65 years of age). available at: http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2014/39943a-e ng.php June 12, 2014.
  • 6.Freedman SB, Uleryk E, Rumantir M, Finkelstein Y. Ondansetron and the risk of cardiac arrhythmias: a systematic review and postmarketing analysis. Ann Emerg Med 2014 Jul;64(1):19-25.e6.
  • 7.Woosley RL, Romero KA. www.Crediblemeds.org, QTdrugs List, AZCERT, Inc. 1822 Innovation Park Dr., Oro Valley, AZ 85755. November 17, 2015.