FDA update on QT prolongation with Ondansetron

Health Care, Medicine Comments Off

  • A new FDA Drug Safety Communication regarding use of ondansetron states that a single 32-mg intravenous dose of ondansetron may cause QT interval prolongation and should be avoided.
  • QT interval prolongation may, in turn, lead to torsades de pointes, an abnormal and potentially fatal heart arrhythmia.
  • No single intravenous dose should exceed 16 mg.
  • After baseline correction, the maximal mean difference in QTcF from placebo was 20 milliseconds for the 32-mg single intravenous dose and 6 milliseconds for the 8-mg single intravenous dose.
  • Risk factors for QT prolongation associated with use of ondansetron include congenital long QT syndrome, congestive heart failure, bradyarrhythmias, or concomitant use of medications that prolong the QT interval.
  • Before ondansetron is administered, electrolyte abnormalities including hypokalemia or hypomagnesemia should be corrected.