March 19, 2015 — The FDA has not issued specific warnings about using Zofran in pregnancy, despite the fact that about 1 million pregnant women use it “off-label” every year and a growing number of studies have found evidence of birth defects.
Zofran (ondansetron) is an anti-nausea drug that was marketed “off-label” to pregnant women by GlaxoSmithKline (GSK). In 2012, the Justice Department ordered the drug-maker to pay $3 billion for improperly marketing Zofran and other drugs.
Beginning in 2011, the FDA has issued multiple warnings about cardiovascular side effects from Zofran, including deadly irregular heart rhythms, QT interval prolongation, and Torsades de Pointes.
Pregnant women with morning sickness (nausea and vomiting) in the first trimester are also at risk of deadly heart rhythm problems, mostly due to fluid depletion and electrolyte imbalances. This electrical disturbance in the heart can also lead to heart problems during pregnancy.
The FDA has issued several recommendations regarding heart rhythm problems from Zofran, including:
- Contact a doctor if you have any concerns or questions about Zofran side effects
- Be aware that you may need to undergo an electrocardiogram (ECG, EKG) to monitor your heart rhythm periodically while you are taking Zofran, especially if you have risk-factors for heart problems.
- The FDA recommends ECG monitoring for patients with risk-factors like electrolyte abnormalities (e.g., hypokalemia or hypomagnesemia), congestive heart failure, bradyarrhythmias, or using other medications that prolong the QT interval.
- Seek emergency medical attention if you experience symptoms like irregular heartbeat, shortness of breath, dizziness, or fainting.