By Diedtra Henderson, The Boston Globe
Feb. 9--WASHINGTON -- The Food and Drug Administration is again considering revising labels of popular antidepressants, this time in response to an article in today's New England Journal of Medicine that linked use of drugs like Paxil, Prozac, and Zoloft late in pregnancy with a condition that can endanger infants' lives.
During a hastily called press conference yesterday, the FDA called the results of a study cited in the article "very concerning."
The agency will issue a public health advisory within days, said Dr. Sandra Kweder, deputy director of the FDA's Office of New Drugs. Its regulatory options include updating drug labels, searching public and private databases to corroborate the drug link to the lung condition, and requiring additional trials from drug manufacturers.
But because the condition -- persistent pulmonary hypertension of the newborn -- is rare and failure to treat maternal depression can cause its own problems, the study's lead author does not expect the FDA to follow the lead of Canadian regulators, who warned against using new-generation antidepressants during pregnancy.
In October 2004, the FDA told manufacturers to add warnings on boxes alerting patients that the antidepressants increase suicidal thoughts and behaviors in children taking them. Last December it warned of an association between Paxil and heart defects when the drug is taken early in pregnancies.
The study described in the Journal article was observational and included interviews with 1,200 women within six months of giving birth. It is unethical to give pregnant women experimental drugs to gauge birth defect risks.
"This is an approach to looking at all medications that pregnant women might take and doing it in a systematic, consistent fashion so that we don't wait years to find out if a drug might cause a problem," said Christina Chambers, the study's lead author and director of a California program that fields 8,000 calls annually about the safety of medicines for developing fetuses.
Up to 15 percent of women of reproductive age suffer major depressive disorders.
The study focused on new-generation antidepressants called selective serotonin reuptake inhibitors. They were the nation's fifth highest selling class of prescription drugs in the first nine months of 2005, accounting for 122.6 million prescriptions, according to IMS Health a pharmaceutical market research firm. About 3 percent of women take that type of antidepressant at some point during pregnancy.
Normally, one to two newborns per 1,000 suffer from persistent pulmonary hypertension, which means their pulmonary arterial pressure is too high at birth. As a result, their lungs can't provide enough oxygen, causing their bodies to produce oxygen-poor blood and sometimes resulting in death. In one study, nearly half the survivors were cognitively delayed, had major neurological problems, and could not hear.
When pregnant women took selective serotonin reuptake inhibitors after 20 weeks gestation, the risk of their infants developing persistent pulmonary hypertension rose sixfold, to about one in 100 newborns. The study size was too small to determine whether one antidepressant was riskier than another.
"This is the latest in a series of troubling reports of possible adverse events" of selective serotonin reuptake inhibitors on fetuses, Dr. James Mills of the National Institutes of Health wrote in an accompanying editorial in the Journal.
Previous studies linked the antidepressants with infants' rapid breathing, jitteriness, bluish skin color from lack of oxygen, difficulty nursing, and low blood sugar.
The FDA said it does not want pregnant women to stop medication without consulting both their obstetricians and doctors providing their mental healthcare.
"This isn't a cause for panic," the FDA's Kweder said. "The risk is small enough that 99 percent of women's babies who are taking these medicines would not be at risk."
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