The intravenous formulation of a drug used to prevent chemotherapy-related nausea and vomiting increases the risk of torsade de pointes and should no longer be used for this indication in children or adults, the Food and Drug Administration announced on Dec. 17.

The drug is dolasetron mesylate, a serotonin 5-HT3 receptor antagonist marketed as Anzemet by Sanofi-Aventis US. Confirming previous suspicions about the IV drug’s effects on the QT interval, a study of 80 healthy adults found that IV dolasetron caused a significant QT prolongation, which can lead to the potentially fatal arrhythmia torsade de pointes, according to the FDA statement. People with underlying heart conditions or those with heart rate or rhythm problems are at particularly high risk for developing QT prolongation.

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Dolasetron tablets can still be used for chemotherapy-induced nausea and vomiting, and because the effect on QT prolongation is dose dependent, the injection formulation can still be used to prevent and treat postoperative nausea and vomiting, because lower doses are used for this indication and "are less likely to affect the electrical activity of the heart and result in abnormal heart rhythms," the statement said.

The drug’s label is being updated to include the contraindications against the use of IV dolasetron for preventing nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy. And existing warnings that the tablet and IV formulations may affect electrical activity of the heart and cause arrhythmias are being strengthened.

Clinicians should report adverse events associated with dolasetron and other drugs to the FDA’s MedWatch program at 800-332-1088.

12/17/10  

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FROM THE FDA

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FDA Takes On Drug-Tainted Dietary Supplements