(UPDATES with new information on Glaxo study in ninth paragraph using United
Healthcare data)
By Jennifer Corbett Dooren
Of DOW JONES NEWSWIRES
WASHINGTON (Dow Jones)--The Food and Drug Administration issued a new warning
Thursday that GlaxoSmithKline PLC's (GSK) Paxil was linked to a possible
increased risk of birth defects.
The FDA first issued the warning in September after two medical studies
showed a slight increase in the risk of birth defects in babies born to women
taking Paxil. However, the agency issued a new drug label Thursday discussing
the studies. It reclassified the drug as a so-called category D drug for
pregnant women, which means that studies have shown risk to a fetus. Previously
the drug, as well as other antidepressants, was classified as a category C
drug, meaning that such risks were found only in animal studies.
The studies involving Paxil suggest an increase in the risk of heart defects.
"FDA is advising health-care professionals not to prescribe Paxil in women
who are in the first three months of pregnancy or are planning pregnancy,
unless other treatment options are not appropriate," the agency said in a
statement.
Paxil and other antidepressants had already carried warnings about the use of
the drugs by pregnant women and suggesting that doctors and patients carefully
weigh the benefits of the drugs against the risks of birth defects. However,
the reclassification of Paxil to a category D drug essentially means the
warning has been strengthened.
The FDA said early results of two studies showed that women who took Paxil
during the first three months of pregnancy were almost two times as likely to
have a baby with a heart defect as women who received other antidepressants or
women in the general population. While the studies suggest the risk of birth
defects is almost double, the risk in real terms is much smaller.
Most of the defects were heart defects, such as holes in the walls in the
chambers of heart which typically range from minor and resolve without
treatment to more severe and require surgery.
The results of the studies were first released in September and a new
analysis was released involving more women and infants.
One of the studies was conducted by GlaxoSmithKline and it involved U.S.
5,556 women on Paxil and other antidepressants during the first trimester of
pregnancy. Information was obtained from a United Healthcare data base.
Overall, the study showed that 4% of infants had some type of congenital
malformation compared with about 2% of infants born to women on other
antidepressants. The rate of birth defects is about 3% for the general
population. A total of 12 infants were born with heart defects among women
using Paxil. The study showed that the percentage of heart defects was 1.5%
among infants born to women using Paxil compared to 1% among women taking other
antidepressants.
"This study showed an upward trend toward an increased risk for
cardiovascular formations for paroxetine (Paxil) compared to other
antidepressants," Glaxo said in a letter directed at health-care professionals.
Another study based on the Swedish Medical Birth Registry looked at 6,896
women exposed to Paxil and similar drugs early in pregnancy. Of those, 815
infants were exposed to Paxil, and researchers found an increased risk of heart
defects. The rate of heart defects among Paxil users was 2% compared with 1%
among users of other antidepressants. The study showed no difference when all
types of birth defects were lumped together.
A Glaxo spokeswoman said the company and the FDA agreed on the new Paxil
label and warning. The label became effective Monday. The FDA typically must
negotiate labeling changes - which include warnings - with drug companies.
-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294;
jennifer.corbett@dowjones.com.
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