Updated Product Labeling Warns of Birth Defect Risk with Paxil

Medical Author: Melissa Conrad Stoppler, MD
Medical Editor: Dennis Lee, MD

The U.S. Food and Drug Administration (FDA) recently announced that early research studies with the drug Paxil (paroxetine) suggest that taking the drug during the first three months of pregnancy may increase a woman's risk of having a baby with birth defects, particularly heart defects.

Paxil is an antidepressant drug belonging to the class of medications known as the selective serotonin reuptake inhibitors (SSRIs). Drugs in this group affect levels of the chemicals that nerves in the brain use to communicate with one another, known as neurotransmitters. Many experts believe that an imbalance among the amounts of the different neurotransmitters in the brain leads to depression. The SSRI class also contains fluoxetine (Prozac) and sertraline (Zoloft). Paxil is approved by the FDA for the treatment of depression and several other psychiatric disorders.

Results of two early studies reviewed by the FDA showed that women who took Paxil during the first three months of pregnancy were about one and a half to two times as likely to have a baby with a heart defect compared with women who took other antidepressants or women in the general population. Most of the heart defects reported in these studies were of the type known as atrial and ventricular septal defects (holes in the walls of the chambers of the heart). These types of heart defects can range in severity from relatively minor that resolve without treatment to those that cause serious symptoms and need to be repaired surgically. The risk for this type of heart defect is approximately one per cent of births in the general population. In one of the studies with Paxil, women taking the drug had an approximately two per cent risk of having a baby with heart defects, and in the second study, women taking Paxil in the first trimester had an approximate 1.5% risk of having a baby with heart defects.