In the 1990's millions of women were put on menopausal hormone drugs to fight hot flashes, night sweats and many other symptoms of menopause. Many respected medical journals saw it as a way of fending off major illness during menopause. In the last seven years however, over 13 000 women have started lawsuits against Wyeth and their menopause drug Prempro, saying the drug caused breast cancer and other problems.

In 2002, researchers stopped the largest clinical trial ever conducted of women’s health because participants who took certain combined hormones had an increased risk of breast cancer, a higher risk of heart attack, stroke and blood clots in the lungs, compared with those taking a placebo. Other parts of the same federal study found that hormone drugs increased the risk of dementia in participants 65 and older.

Drug giant Pfizer, which absorbed Wyeth and its hormone drugs in a merger this year, says that Prempro is a safe, federally approved drug. Chris Loder, a Pfizer spokesman, says Wyeth acted responsibly by including a clear warning about a breast cancer risk on Prempro labels and by updating the warning as new evidence emerged. Doctors who know of the risks of this drug still say it is the most effective treatment for symptoms directly associated with menopause.

Pfizer representatives say court documents paint an unfair picture of Wyeth’s practices and that plaintiffs’ lawyers have cherry-picked documents for out-of-context comments to sway juries. Mr. Loder also notes that Pfizer plans to appeal every product-liability case on menopausal drugs it loses.