As you may already have heard, the FDA informed healthcare professionals and the public that preliminary results from a recently completed clinical study suggest that a 32 mg single intravenous dose of ondansetron (Zofran, ondansetron hydrochloride, and generics) may prolong the QT interval which could pre-dispose patients to develop Torsades de Pointes.

The FDA will evaluate the final study results, when available, and will work with GlaxoSmithKline to explore an alternative single dose regimen that is both safe and effective for the prevention of chemotherapy-induced nausea and vomiting. This information does not change the recommended lower dose intravenous ondansetron used to prevent post-operative nausea and vomiting.

Though the new information on QT prolongation does not change any of the recommended oral dosing regimens for ondansetron, we recommend reviewing the following paper from the New England Journal of Medicine, which suggests there may be risks involved with the oral use of ondansetron. Ray WA, Murray KT, et al. Azithromycin and the risk of cardiovascular death. NEJM 2012 May 17;366(20):1881-90.

Ondansetron (Zofran) is already included on the Drugs to Avoid list for people diagnosed with Long QT Syndrome.


If you have any questions, please do not hesitate to contact us at 800-STOP-SAD or Christine@sads.org.

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