New estrogen-releasing skin patches may provide a safer way for women to take the hormone to relieve the side effects of menopause and other problems of aging, California researchers say.
The patches steadily release estrogen through the skin when stuck onto the abdomen. They must be replaced twice a week.
Researchers at UCLA say the patches appear to reduce the chance of side effects of estrogen therapy that result from the impact of the hormone on the liver.
The patches, produced by Ciba-Geigy Corp., are not yet on the market. However, spokeswoman Kathleen Coughlin said the drug company hopes to get permission from the Food and Drug Administration this summer to sell estrogen patches as prescription drugs.
An estimated 4 million to 5 million American women take estrogen. During menopause, the hormone relieves hot flashes and irritability. Studies suggest that it also lowers the risk of brittle bones, vaginal atrophy and heart disease in elderly women.
Increases Cancer Threat
However, the drug also increases the threat of uterine cancer. But doctors believe that it can be minimized by combining estrogen with progesterone, another hormone.
Some experts believe that estrogen also increases the risk of gallbladder disease, high blood pressure, blood clots and high blood cholesterol levels. These apparently result from the effect of estrogen pills on the liver.
The new study found that estrogen taken with patches largely bypasses the liver.
Doctors compared estrogen pills with patches that delivered a form of estrogen called estradiol. The study was conducted on 23 post-menopausal women.
"It may be possible to administer estradiol by a non-oral route and continue to get the benefits on hot flashes, the vagina and bone without exerting any measurable effect on the liver," said Dr. Howard L. Judd, one of the UCLA researchers.
Judd said that even when they wear the patches, women will still need to take progesterone pills to guard against uterine cancer.