1998 Pfizer Report Warned of a Potential Link Between the Antidepressant Drug Zoloft and Birth Defects


A scientist warned Pfizer Inc. executives about a potential link between the antidepressant drug Zoloft and birth defects. A 1998 company report obtained by Bloomberg shows the scientist recommended changes to the drug’s safety warning.

Pfizer has been trying to fend off lawsuits brought by the parents of children born with malformed hearts and the revelation could make the process more difficult for the drug maker. Pfizer flatly denies the notion that Zoloft caused birth defects in newborns and said Monday the document from a company drug-safety official was taken out of context and by lawyers suing the firm, according to Bloomberg.

More than 1,000 lawsuits have been filed against Pfizer alleging the company sold Zoloft knowing the medication could cause cardiac abnormalities in newborns. The company won the first lawsuit to go to trial in April over the drug, which was once the country’s most-prescribed antidepressant. The win occurred before the document was released last week in a Philadelphia, Pennsylvania, case, Bloomberg reported.

Pfizer admits the drug manufacturer found more than a dozen side-effect reports about babies’ birth defects, and acknowledges it could exclude the possibility that the babies’ mother’s use of the drug during pregnancy could not be ruled out; however, the company said the internal reports summarizing the Zoloft studies and the review of side-effect reports were mischaracterized by the plaintiff’s lawyers, according to Bloomberg.

“Plaintiffs also have cherry-picked data from Pfizer’s review of adverse event reports and ignored the conclusions of these reports that contradict their testimony,” Christine Regan Lindenboom, a Pfizer spokeswoman, said in an e-mailed statement viewed by Bloomberg.

According to the report, Pfizer found 25 cases involving “congenital abnormalities” or other “adverse events” that were considered to be “possibly related” to Zoloft. When researchers probed further, they found in 16 of the cases, “there was no obvious cause” for the defect other than the mother’s use of the medication while pregnant, Bloomberg reported.

The Philadelphia case involves a woman who alleges her cardiac defects, including a hole in her heart, are the result of her bipolar mother’s use of Zoloft. The family is seeking at least $2.4 million in damages to cover the woman’s future medical expenses. The case is similar to a lawsuit filed against GlaxoSmithKline Plc (GSK) over its Paxil antidepressant medication. In 2010, the London-based drug manufacturer agreed to pay more than $1 billion to settle more than 800 lawsuits accusing the company of ignoring birth-defect risks. GSK also paid $3 billion to resolve a government investigation of allegations it illegally promoted prescription drugs including Paxil, according to Bloomberg.