The maker of the most popular hormone therapies for post-menopausal women has told doctors that there are possibly increased risks from all its estrogen-based products, and that their labels will now reflect that concern.

The new company information will state that estrogen products shouldn't be taken to prevent heart disease and should be taken for as short a time as possible. In addition, doctors were told to carefully consider alternatives to estrogen when trying to prevent osteoporosis in patients.

The new labeling follows the conclusions from a large government study this summer that found potentially serious side effects from hormone replacement therapy.

That study involved Prempro, a combination of the hormones estrogen and progestin, but the new labeling will apply to estrogen-only Premarin too. While the Women's Health Initiative (WHI) study of Prempro was halted due to increased incidence of heart disease and breast cancer, the arm of the study using Premarin was allowed to continue.

"When we considered the implications of the study, we decided we wanted to apply the information to all the post-menopausal hormone therapies," said Victoria Kusiak, North American medical director for Wyeth Pharmaceuticals, the maker of the drugs.

Questioning risks

"The absence of data does not imply safety, and there's no way of telling from the study whether the risks were from the estrogen or the estrogen in combination with progestin."

The new labeling was developed by Wyeth in consultation with the Food and Drug Administration.

The issue of how estrogen therapy should be used remains in flux, however, and FDA officials said the label may well change after meetings this fall.

The Office of Research on Women's Health at the National Institutes of Health will sponsor a forum on menopausal hormone therapy Oct. 23-24, and the FDA is expected to hold an advisory committee meeting on the subject soon after.

Reflecting the complexity of the subject, the new Wyeth labeling will tell doctors to carefully consider alternatives to estrogen when using it solely to prevent the bone-thinning disease osteoporosis.

One of the accepted indications for the estrogen products is prevention of post-menopausal osteoporosis, and the WHI study found that women taking Prempro did experience fewer osteoporosis-related hip fractures.

The study also found, however, an increased incidence of heart disease, breast cancer and stroke among women taking Prempro for five years. The study was especially surprising, because researchers had believed estrogen could protect the heart.

A Wyeth official said that Prempro sales dropped by about 30 percent in the month following the study's release and that Premarin sales declined by about 15 percent. Before the study, about 14 million American women took the hormone treatments.