Before 2002, hormones were routinely prescribed to women experiencing menopausal symptoms. Not only did estrogen (Premarin) or estrogen-progestin combination (Prempro) effectively treat the hot flashes, night sweats, and discomforting vaginal symptoms; women reported feeling great.
In 1941, the Canadian company Ayerst, McKenna & Harrison, Ltd., released a product obtained from pregnant mares’ urine—Premarin—that contained a mixture of some ten estrogens. Approved for treating menopausal symptoms in the United States in 1942, it was natural, meaning “safe,” to many. Between the late 1950s and early 1970s, a series of medical papers and popular books portrayed menopause as a disease of estrogen deficiency and extolled the long-term use of Premarin (hormone replacement therapy, HRT) to combat it, to prevent osteoporosis, and to protect the heart in menopausal and postmenopausal women. Sales increased significantly.
Scientific reports in 1975 established that estrogen therapy increased the risk of endometrial (uterine) cancer, and sales dropped precipitously by 1980. Yet, thanks to aggressive promotion to doctors and direct-to-consumer ads, from 1992 to 2000 Premarin became one of the two most popular drugs in America. The addition of a progestin to estrogen in 1995 reduced the danger of endometrial cancer.
The Women’s Health Initiative (WHI) initiated two extensive, long-term clinical trials in the early 1990s to scientifically establish the beneficial effects of Prempro and Premarin in postmenopausal women. The Prempro study ended early in 2002 and unexpectedly concluded that Prempro users had a higher incidence of heart attacks, strokes, blood clots in the lungs, and breast cancer than placebo users; conversely, there were fewer cases of colorectal cancer and bone fractures. In the Premarin study, drug users had greater risks of strokes, blood clots, breast cancer, and possibly heart disease and dementia. Understandably, sales of Prempro and Premarin plunged!
Some of WHI results have been challenged and are being reevaluated for subsets of postmenopausal women. While HRT is highly effective in relieving menopause symptoms, women should critically weigh the risks. If drugs are used, it should be at the lowest doses for the shortest time (one to two years).
SEE ALSO Estrone and Estrogen (1929), Progesterone and Progestin (1933), Diethylstilbestrol (1938), Placebos (1955).
Menopause has been a source of humor but not for those experiencing its sometimes highly distressing symptoms. Premarin’s and Prempro’s ability to relieve these symptoms is well accepted, but do their benefits outweigh potential long-term risks?