As life expectancy increases, women will be postmenopausal for one-third of their lives, therefore medications designed to improve their health are of ever increasing importance. Doctors are enthusiastic about prescribing estrogens to women at the time of menopause in order to reduce the risk of osteoporosis-related fractures and heart disease. Unfortunately, there are many side effects from estrogens, like estradiol and Premarin, including an increase in the risk of breast and uterine cancer, and blood clots (deep vein thrombosis and pulmonary embolism), as well as troublesome vaginal bleeding (half of women) and breast tenderness (one third of women). Because of side effects, less than one fifth of women ever take estrogens and nearly half of those who begin treatment discontinue use within one year.

An optimal hormone replacement therapy would retain the benefits of estrogen while being free of the adverse side effects. Drugs have been designed to specifically effect different tissues in different ways. The first such successful "designer drug" was the antiestrogen tamoxifen used for the treatment of breast cancer for the past 2 decades. This drug suppresses breast cancer, but increases hot flashes. In addition to its antiestrogen effects, it also has estrogen stimulating effects on the uterus, bones, and LDL "bad" cholesterol, resulting in more endometrial cancer, but stronger bones and lower cholesterol.

Recently a new "designer drug," raloxifene (Evista), was introduced to the market, which does not stimulate the uterus and may not stimulate the breasts. Breast tenderness is not a side effect, and an increase in breast and uterine cancer, as seen with estrogens, is not expected. The positive effects on bone density are about half of those of estrogen. LDL cholesterol is lowered as much by raloxifene as by estrogen, but other heart disease-preventing factors are improved much less by raloxifene (JAMA 279:1445, 1998). Only 1 of 3 trials has shown a reduction in heart disease with raloxifene (JAMA 279:1483, 1998). Like estrogen and tamoxifen, raloxifene increases the risk of blood clots. Leg pain and hot flashes are also increased over placebo (N Engl J Med 338:1313, 1998). Raloxifene does not decrease the ovary’s production of estrogen and premenopausal women who take raloxifene will continue to ovulate; therefore may become pregnant (J Clin Endocrinol Metab 83:6, 1998). The drug can harm the unborn fetus (Med Lett Drugs Ther 40:29, 1998).

Overall, raloxifene’s major benefit of not stimulating the uterus may help a few women, however, this is offset by the fact that it probably does not reduce the risk of heart disease. Side effects are fewer, which will improve compliance. Many women use estrogen for strengthening and moisturizing their vaginal tissues. Raloxifene does not appear to offer these benefits. The long-term safety and effectiveness of the drug has not be established, and direct comparisons with other drugs are still lacking (Med Lett Drugs Ther 40:29, 1998). The dosage of raloxifene is 60 mg a day and a 30-tablet bottle costs about $60.