Raloxifene: A Review

women can now expect to live up to one-third of their lives in the post-menopausal state. This low estrogen state is a major risk factor for the development of osteoporosis and cardiovascular disease. The Osteoporosis Society of Canada currently recommends estrogen as the treatment of choice for preventing post-menopausal osteoporosis. Sustained unopposed estrogen use is associated with an increased risk of endometrial hyperplasia and endometrial cancer, necessitating the concomitant use of a progestin in those with an intact uterus. Recent large cohort studies suggest that estrogen and estrogen/progestin therapy may also be associated with an increased risk of breast cancer thus diminishing the beneficial effects of estrogen on overall mortality. Bisphosphonates are also available for the treatment and prevention of osteoporosis. They do not have the other beneficial effects that estrogen may provide. Selective estrogen receptor modulators (SERMs) represent a new therapeutic class of medications that have been developed to act as estrogen agonists in some tissues and estrogen antagonists in others. Raloxifene (Evista®) is a selective estrogen receptor modulator that, in pre-clinical and clinical studies, demonstrates estrogen agonist activity on bone and lipid metabolism, and shows estrogen antagonist activity on uterine and breast tissue. It is the first estrogen receptor active agent that has been shown in adequately powered, placebo-controlled, randomized clinical trials, to reduce the risk of new vertebral fractures in post-menopausal women with osteoporosis.