FDA Issues Warning on Arrhythmia Risk with Ondansetron

The antinausea drug ondansetron (marketed as Zofran and in generic forms) should not be used in patients with congenital long QT syndrome, as they are at particular risk for developing torsade de pointes while taking the drug, the FDA warned on Thursday.

Also at increased risk are patients with congestive heart failure or bradyarrhythmias, those predisposed to low potassium and magnesium levels, and those taking other drugs that can lead to QT prolongation. Accordingly, ECG monitoring is now recommended for such patients using ondansetron.

The drug's label is being revised to include this new information. (The label had previously noted the potential for QT prolongation.) The FDA asks clinicians to report incidents to its Adverse Event Reporting Program.