Glaxo adds birth defect caution to Paxil label

• Drug News • Sep 28, 05

GlaxoSmithKline Plc is alerting physicians about a study suggesting the company’s antidepressant Paxil may be linked more often to birth defects than similar drugs, U.S. regulators said on Tuesday.

The British drug maker, in a letter to physicians, said it was adding the information to the prescribing instructions on Paxil’s label. Glaxo said it was difficult to tell if Paxil caused the defects, most of which were cardiovascular, in infants born to women who took the drug while pregnant.

“Preliminary results suggest an increase in the risk of congenital malformations associated with the use of (Paxil) as compared to other antidepressants,” the company’s letter to physicians said.

“The preliminary results of this study and recent abstracts ... differ from previous epidemiologic studies, making it difficult to conclude whether a causal relationship exists,” it said.

Physicians should “carefully weigh the potential risks and benefits of using paroxetine (Paxil) therapy in women during pregnancy and ... discuss these findings as well as treatment alternatives with their patients,” the FDA said.

The new study examined records of infants born to 3,581 women who took Paxil or other antidepressants during the first trimester of pregnancy.

A preliminary analysis found infants born to women who took Paxil were more likely to be born with an abnormality than babies born to women who took another antidepressant, Glaxo said. Overall, 4 percent of babies had some type of malformation. The typical rate for birth defects among infants is about 3 percent.

“GSK is conducting additional epidemiologic studies to more fully understand these preliminary findings,” the company said.

An earlier study of 4,291 infants found no increased risk of birth defects for women who took Paxil early in pregnancy, Glaxo said.

Glaxo’s letter to doctors is available online at http://www.fda.gov/medwatch/safety/2005/safety05.htm#Paxil2.