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FDA Drug Safety Podcast for Healthcare Professionals: New information regarding QT prolongation with ondansetron (Zofran)

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Narrator: Welcome to the FDA Drug Safety Podcast for Healthcare Professionals from the Division of Drug Information. Today’s topic: New information regarding QT prolongation with Zofran, active ingredient ondansetron. 

This update is in follow-up to the FDA Drug Safety Communication: Abnormal heart rhythms may be associated with use of Zofran, or ondansetron, on 9/15/2011.

CAPT Patty Garvey, a US Public Health Service pharmacist in the Division, will provide you with additional information about this Communication.
Guest Speaker: On June 29, 2012, FDA issued a Drug Safety Communication informing healthcare professionals and the public that preliminary results from a recently completed clinical study suggest that a 32 mg single intravenous dose of ondansetron, marketed as Zofran, ondansetron hydrochloride, and generics, may cause QT interval prolongation, which could pre-dispose patients to develop an abnormal and potentially fatal heart rhythm known as Torsades de Pointes.
GlaxoSmithKline has announced changes to the Zofran drug label to remove the 32 mg single intravenous dose. The updated label will state that ondansetron can continue to be used in adults and children with chemotherapy-induced nausea and vomiting at the lower intravenous dose recommended in the drug label, a dose of 0.15 mg/kg administered every 4 hours for three doses; however, no single intravenous dose should exceed 16 mg. Information from the new clinical study will be included in the updated drug label. 
FDA will evaluate the final study results when available, and will work with GSK to explore an alternative single dose regimen that is both safe and effective for the prevention of chemotherapy-induced nausea and vomiting in adults. 
The new information on QT prolongation does not change any of the recommended oral dosing regimens for ondansetron.  It also does not change the recommended lower intravenous dosing of ondansetron to prevent post-operative nausea and vomiting. 
As part of the ongoing safety review of ondansetron, FDA continues to assess data about the risk of QT prolongation and will update the public when more information becomes available.
At this time FDA recommends Healthcare Professionals be aware of the following:
  • ECG changes including QT interval prolongation have been observed in patients receiving ondansetron. In addition, Torsade de Pointes, an abnormal, potentially fatal, heart rhythm, have been reported in some patients receiving ondansetron.
  • The use of a single 32 mg intravenous dose of ondansetron should be avoided.  New information indicates that QT prolongation occurs in a dose-dependent manner, and specifically at a single intravenous dose of 32 mg.
  • Patients who may be at particular risk for QT prolongation with ondansentron are those with congenital long QT syndrome, congestive heart failure, bradyarrhythmias, or patients taking concomitant medications that prolong the QT interval.
  • Electrolyte abnormalities (e.g., hypokalemia or hypomagnesemia) should be corrected prior to the infusion of ondansetron.
  • The lower dose intravenous regimen of 0.15 mg/kg every 4 hours for three doses may be used in adults with chemotherapy-induced nausea and vomiting. However, no single intravenous dose of ondansetron should exceed 16 mg due to the risk of QT prolongation.
  • The new information does not change any of the recommended oral dosing regimens for ondansetron, including the single oral dose of 24 mg for chemotherapy induced nausea and vomiting.
  • The new information also does not change the recommended lower dose intravenous dosing to prevent post-operative nausea and vomiting.
  • Adverse events involving ondansetron should be reported to the FDA MedWatch program at www.fda.gov/medwatch.

Narrator: Thank you for listening. The FDA is committed to keeping healthcare professionals informed of the latest safety information. A link to this communication, including the complete Data Summary, can be found at www.fda.gov/DrugSafetyCommunications.   If you have drug questions, you can reach us at druginfo@fda.hhs.gov.
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