- A selective estrogen receptor modulator (SERM) that has estrogen-agonistic effects on bone and lipid metabolism but estrogen-antagonistic effects on breast and uterus; used in the prophylaxis of osteoporosis after menopause.R. is a benzothiophene derivative that binds to estrogen receptor sites. Besides conferring protection against osteoporosis after menopause, it has been shown to improve bone mineral density and reduce the risk of fractures in established osteoporosis. The reduction in fracture risk is greater than would be expected from the increase in bone density. Unlike tamoxifen, which also reduces osteoporosis risk, r. does not heighten the risk of endometrial cancer. Although r. increases bone mineral density to a lesser degree than estrogen, it reduces the risk of breast cancer rather than increasing it as estrogen may perhaps do. Hence it may be preferred for women who fear breast cancer or are at high risk for it. Like hormone replacement therapy with estrogen-progestogen, r. decreases LDL cholesterol, fibrinogen, and lipoprotein(a), increasing HDL cholesterol without raising triglycerides. It does not relieve hot flashes; in fact, it causes them in 25% of patients. Like estrogen replacement therapy, it is contraindicated in pregnancy and in women with a history of thromboembolism. Whether it protects against cardiovascular disease and Alzheimer dementia as estrogen does has not yet been determined.
* * *ral·ox·i·fene .ral-'äk-sə-.fēn n a selective estrogen receptor modulator that is administered orally in the form of its hydrochloride C28H27NO4S·HCl as prophylaxis against osteoporosis after menopause, that binds with estrogen receptors to act as an estrogen agonist promoting bone mineralization and lipid metabolism, and that is believed to spare breast and uterine tissues the cancer-producing effects of estrogen by acting as an estrogen antagonist in those tissues see EVISTA
* * *n.a drug used to prevent osteoporosis that develops after the menopause. It mimics the protective action of oestrogen in the bones by acting selectively on oestrogen receptors; unlike hormone replacement therapy, it does not relieve menopausal symptoms. It is administered by mouth; side-effects include hot flushes, and there is a risk of thromboembolism and thrombophlebitis. Trade name: Evista.
Medical dictionary. 2011.