The U.S. Food and Drug Administration (FDA) is clarifying dosing and warning recommendations for the antidepressant Celexa (citalopram hydrobromide; also available in generic form).  In August 2011, FDA issued a Drug Safety Communication (DSC) stating that citalopram 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. 

Citalopram use at any dose is discouraged in patients with certain conditions because of the risk of QT prolongation, but because it may be important for some of those patients to use citalopram, the drug label has been changed to describe the particular caution that needs to be taken when citalopram is used in such patients. The revised drug label also describes lower doses that should be used in patients over 60 years of age. 

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. 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.

The citalopram drug label was revised on August 12, 2011 and again on March 27, 2012, to include new warnings about the potential for QT interval prolongation and Torsade de Pointes, as well as new drug dosage and usage recommendations.