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The U.S. Food and Drug Administration (FDA) approved Prempro, also known as conjugated estrogen/medroxyprogesterone acetate, in November 1995, to relieve menopause symptoms and osteoporosis. It is a combination of two hormones, an estrogen and a progestin, and is used only by menopausal women who have not undergone hysterectomy.

Prempro was the first estrogen/progestin combination drug available for hormone replacement therapy (HRT), and is still one of the most common HRT's prescribed by physicians today. In 2003, it was estimated that more than 10 million postmenopausal women in the U.S. take estrogen or estrogen-progestin products to treat the symptoms of menopause. Prempro is manufactured by Wyeth-Ayerst Laboratories.

Health Concerns Regarding Prempro

In 1991, the National Heart, Lung, and Blood Institute (NHLBI) began a long-term study of ways to prevent heart disease, breast and colorectal cancer, and osteoporosis in women, called the Women's Health Initiative ("WHI"). The WHI consists of a set of clinical studies and an observational study, and involves more than 161,000 healthy, postmenopausal women.

One of the clinical studies involved 16,608 women who took either Prempro or a placebo. The main goal of this study was to see if Prempro would help prevent heart disease and hip fractures. The Prempro portion of that study was cut short three years early, however, because the researchers determined that the risks associated with Prempro, which include breast cancer, stroke, heart disease and blood clots, outweighed its benefits, which include a lower rate of fractures and a reduction in the risk of colorectal cancer. Women had been studied in the trial for over 5 years before it was halted.

Most of the women in the Prempro portion of the WHI study did not have prior evidence of heart disease, so the increased risk in healthy women of incidents like heart attack or stroke was a new finding, according to researchers. Unfortunately, because of differences in the formulas of other combination estrogen/progestin products, it was unclear whether the concerns of this study should also be considered for other, similar products.

Wyeth immediately announced supplemental Prempro labeling describing the conclusions from the cancelled WHI study. On August 14, 2002, the Food and Drug Administration's Center for Drug Evaluation and Research (CDER) announced it was going to review the risks and benefits of Prempro in light of the WHI findings.

FDA Action

The FDA announced in early January 2003, that it had approved new labels for Prempro, adding a new boxed-warning to emphasize increased risk for heart disease, heart attacks, strokes and breast cancer. Besides incorporating the WHI findings, the updated labels would now state that Prempro should not be used to prevent CHD, should be used the shortest amount of time possible for specific treatment goals, should be periodically reevaluated, and should be "carefully considered" for use only to prevent osteoporosis, or treat vaginal dryness and irritation, because alternative, non-hormonal treatments carried less risk. The FDA also indicated it was asking all manufacturers of estrogen and estrogen-progestin products to add similar warnings to labels and patient information leaflets.

Currently both the FDA and Wyeth seek to minimize risks and maximize benefits of Prempro by ensuring that women and health care providers fully understand all of its risks and benefits, especially through a "lowest effective dose" approach to treatment.

Get Help Now

While almost all medications have some anticipated side effects, a drug manufacturer has a duty to adequately inform physicians regarding the known risks associated with its drugs. If a manufacturer fails to do so, it can be held responsible to patients who are injured as the result of inadequate warnings, under a legal theory known as product liability.

If you or a loved one have taken Prempro and experienced any unusual side effects or suffered injury, you should contact a physician for proper medical attention. Your next step should be to contact a product liability attorney, who can assess your legal rights and help you obtain compensation for any injuries suffered.

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Next Steps

Contact a qualified product liability attorney to make sure your rights are protected.

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