The FDA has called on GlaxoSmithKline (GSK) to strengthen the warning on its
top-selling antidepressant Paxil to alert consumers that clinical studies in
pregnant women demonstrate the drug poses a risk to the fetus.
The agency's requested labeling change comes roughly nine weeks after GSK sent a letter to physicians warning that pregnant women exposed to Paxil (paroxetine HCl) or Paxil CR (paroxetine HCl controlled-release tablets) during the first trimester were more than twice as likely to have a child with birth defects than women taking other antidepressants. GSK's warning was based on preliminary data from a GSK-led retrospective epidemiologic study involving nearly 3,600 pregnant women, according to the letter.
Based on the preliminary data, GSK updated Paxil's labeling to reflect the clinical trial results. Since that time, data from a second study has emerged, suggesting similar health risks in pregnant women, the FDA said. The second study showed that the risk of heart defects in infants whose mothers had taken Paxil in the first three months of pregnancy was 1.5 percent, compared to 1 percent on mothers who took other antidepressants. GSK has also updated its labeling to reflect the preliminary data from the second trial, the agency said.
The FDA has also asked GSK to change the pregnancy category on Paxil's labeling from "C" to "D," a stronger warning. Category D means that controlled or observational studies in pregnant women have demonstrated a risk to the fetus. Category C indicates there are no adequate or well-controlled studies in humans to determine the effect of the drug on the fetus.