The label for Celexa (citalopram), a selective serotonin reuptake inhbitor antidepressant, has been revised to clarify warnings about its association with abnormal heart rhythms. According to the U.S. Food & Drug Administration (FDA), Celexa should no longer be used at doses greater than 40 mg per day because it could cause potentially dangerous abnormalities in the electrical activity of the heart.
Changes in the electrical activity of the heart (specifically, prolongation of the QT interval of the electrocardiogram [ECG]) can lead to a risk of an abnormal heart rhythm called Torsade de Pointes, which can be fatal, according to the FDA.
Patients at particular risk for developing prolongation of the QT interval include those with underlying heart conditions and those who are predisposed to having low levels of potassium and magnesium in the blood.
Celexa is being discouraged in people with certain conditions, including congenital long QT syndrome, bradycardia, hypokalemia, or hypomagnesemia, recent acute myocardial infarction, or uncompensated heart failure.
Use of Celexa is also not recommended for patients
Use of Celexa is also not recommended for patients who are taking other drugs that prolong the QT interval.
According to the FDA, the maximum recommended dose of citalopram is 20 mg per day for patients with hepatic impairment, patients who are older than 60 years of age, patients who are CYP 2C19 poor metabolizers, or patients who are taking concomitant cimetidine (Tagamet) or another CYP2C19 inhibitor, because these factors lead to increased blood levels of citalopram, increasing the risk of QT interval prolongation and Torsade de Pointes.
In 2011, a total of approximately 31.5 million prescriptions were dispensed for Celexa and generics from U.S. outpatient retail pharmacies. That same year approximately 7.2 million patients received a dispensed prescription for citalopram from U.S.