The Food and Drug Administration (FDA) has determined that exposure to paroxetine in the first trimester of pregnancy may increase the risk for congenital malformations, particularly cardiac malformations. At the FDA’s request, the manufacturer has changed paroxetine’s pregnancy category from C to D and added new data and recommendations to the Warnings section of paroxetine’s prescribing information. Paroxetine is available as Paxil, Paxil CR, Pexeva, and generic paroxetine hydrochloride.

The FDA’s conclusions and changes in paroxetine’s prescribing information are based on preliminary analyses of two recent unpublished epidemiology studies.

• In a study using Swedish national registry data, women who received paroxetine in early pregnancy had an approximately 2-fold increased risk for having an infant with a cardiac defect compared to the entire national registry population (the risk of a cardiac defect was about 2% in paroxetine-exposed infants vs. 1% among all registry infants).
• In a separate study using a United States insurance claims database, infants of women who received paroxetine in the first trimester had a 1.5-fold increased risk for cardiac malformations and a 1.8-fold increased risk for congenital malformations overall compared to infants of women who received other antidepressants in the first trimester. The risk of a cardiac defect was about 1.5% in paroxetine-exposed infants vs. 1% among infants exposed to other antidepressants.
• Most of the cardiac defects observed in these studies were atrial or ventricular septal defects, conditions in which the wall between the right and left sides of the heart is not completely developed. In general, septal defects are one of the most common type of congenital malformations. They range from those that are symptomatic and may require surgery to those that are asymptomatic and may resolve on their own. It is of note that the data in these studies was limited to first trimester exposures only, and there are not currently data to address whether this or any other risk extends to later periods of pregnancy.