Anti-Nausea Medication Zofran Linked To Abnormal Heart Rhythm
On September 15, 2011, the United States Food and Drug Administration issued a safety announcement about the drug Zofran because it may increase the risk of heart arrhythmias, which can be fatal. The manufacturer has been ordered to conduct a study of the effects Zofran may have on the electrical activity of the heart. Results of the study should be available by the summer of 2012. Also, changes have been made to the drug’s label to reflect this warning.
The Medication Zofran
Ondansetron is an anti-nausea medication that has been manufactured and sold by GlaxoSmithKline since 2006 under the brand name of Zofran. It is a 5-HT3 receptor antagonist that is prescribed to help patients control the vomiting and nausea that occurs from surgery, chemotherapy for cancer, and radiation therapy.
Zofran works by blocking the chemical serotonin that occurs naturally in the body that is responsible for triggering the vomiting and nausea. It has been available in tablets, oral solution, and intravenously.
Minor side effects include headache, diarrhea, constipation, or being tired, drowsy, or dizzy. Serious side effects include allergic reactions; pain in the chest, stomach, or jaw; numbness in a limb; fever; seizures; severe headache; changes in vision; fainting; and irregular heartbeats.
The FDA issued its warning because Zofran can cause the QT interval in the heart’s rhythm to be lengthened. The QT interval is the length of time between the contraction of the muscle and the recovery of it. When this time span gets longer, it can lead to arrhythmias of the heart, which are deviations in the normal rhythm of the heart. These include Torsade de Pointes, which is a heart rhythm that is fast and irregular. The rapid beating causes the brain to not receive enough blood and fainting may result. Left untreated, this can cause ventricular fibrillation, which means the heart is not functioning. This can lead to brain damage or death.
Patients that are most at risk for these complications are those who have heart conditions, like long QT syndrome; anyone taking drugs that cause prolongation of the QT interval; and anyone with low levels of magnesium and potassium in their blood.