Ondansetron/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:

Serious. These medicines may interact and cause very harmful effects. 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 any 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 October, 2021.
  • 3.USFood and Drug Administration. FDA Drug Safety Communication: Abnormal heart rhythms may be associated with use of Zofran (ondansetron). available at: https://wayback.archive-it.org/7993/20170722185907/https:/www.fda.gov/Drug s/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.Li K, Vo K, Lee BK, Addo N, Coralic Z. Effect of a single dose of i.v. ondansetron on QTc interval in emergency department patients. Am J Health Syst Pharm 2018 Mar 1;75(5):276-282.
  • 8.USDepartment of Health and Human Services Food and Drug Administration. ICH E14 Clinical Evaluation of QT/QTc Interval Prolongation and Proarrhythmic Potential for Non-Antiarrhythmic Drugs. Available at: https://www.fda.gov/media/71372/download October, 2005.
  • 9.Phansalkar S, Desai AA, Bell D, Yoshida E, Doole J, Czochanski M, Middleton B, Bates DW. High-priority drug-drug interactions for use in electronic health records. J Am Med Inform Assoc 2012 Sep-Oct; 19(5):735-43.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.