ACE Inhibitors May Boost Birth Defects

June 7, 2006 -- The FDA is encouraging women who are taking a class of drugs called ACE inhibitors, which lower blood pressure, to reconsider the use of those drugs before or during pregnancypregnancy.

That advice comes in the wake of a study published in The New England Journal of Medicine showing a higher rate of birth defects in babies born to women who filled prescriptions for ACE inhibitors in the first trimester of pregnancy.

ACE inhibitors are known to raise the risk of birth defects when taken later in pregnancy. The new study suggests that those risks may start earlier in pregnancy.

Examples of ACE inhibitors include Zestril, Prinivil, Accupril, Monopril, and Lotensin. The new study looks at ACE inhibitors in general, without mentioning specific drugs.

FDA: Reconsider Meds, but Don't Panic

"This isn't something to panic about. These are preliminary data," the FDA's Sandra Kweder, MD, told reporters in a teleconference. "But nonetheless, women should seek to change their medicine as soon as they become pregnant," she says.

Kweder is the deputy director of the FDA's Office of New Drugs at the Center for Drug Evaluation and Research.

"I think what's most important about the study is that it just brings to light the importance of women carefully reviewing medication information with their health care providers before becoming pregnant or as soon as they become pregnant, and being aware of the potential risks of certain medicines," Kweder says.

'Black Box' Warning

ACE inhibitors already carry a "black box" warning about birth defects when the drugs are taken during the second and third trimester of pregnancypregnancy. A black box warning is the FDA's strongest warning.

"The reason for that is that we've known for at least a decade, if not longer, that these drugs, when exposure occurs in the second half of pregnancy, are associated with abnormal kidney functions in infants, as well as sometimes abnormalities of the kidney anatomy itself," says Kweder.

The warning doesn't specifically mention the first trimester, but it states "that use of ACE inhibitors should be stopped or discontinued as soon as possible when pregnancy is detected," Kweder says.

The FDA will issue a public health advisory and fact sheets reinforcing that message, says Kweder. Until the FDA reviews the issue, Kweder says there are no plans to change the drugs' warnings.