Raloxifene: A Selective Estrogen Receptor Modulator for the Prevention of Osteoporosis

Abstract

Objective: To review the efficacy and safety of the selective estrogen receptor modulator raloxifene hydrochloride in the prevention of osteoporosis. Data Sources: A MEDLINE search (January 1966–May 1998) and unpublished data obtained from the manufacturer were used to identify relevant studies and review articles. Additionally, bibliographies of selected articles were reviewed. Only English-language articles on human studies were obtained. Study Selection: Literature was reviewed to evaluate the pharmacology, pharmacokinetics, therapeutic use, adverse effects, and drug interactions of raloxifene. Additional relevant citations were used in the introduction material and clinical controversy section. Data Extraction: Clinical trials reviewing raloxifene for the prevention of osteoporosis were evaluated. Data Synthesis: Raloxifene hydrochloride is a partial estrogen agonist that displays both estrogenic and antiestrogenic effects. As a result of binding to estrogen receptors, raloxifene therapy, like estrogen treatment, causes positive changes in biochemical markers of bone turnover such as serum osteocalcin, serum alkaline phosphatase, urinary pyridinoline cross-links, and urinary calcium excretion. In addition, raloxifene increases bone mineral density. Furthermore, raloxifene reduces total serum cholesterol and serum low-density lipoprotein cholesterol. Raloxifene has no effect on serum high-density lipoprotein cholesterol. As a selective estrogen receptor modulator, raloxifene does not display the deleterious effects of estrogen in endometrial or breast tissue. The most common adverse effects are hot flashes and leg cramping. Conclusions: Clinical trials have found that raloxifene is effective in the prevention of osteoporosis, making the drug an alternative choice for the prevention of osteoporosis in patients who are concerned about the proliferative effects of estrogen replacement therapy on the endometrium or breast tissue. Raloxifene may not be a good alternative in women experiencing troublesome hot flushes during menopause. The use of raloxifene in the treatment of osteoporosis and in the prevention of breast cancer is currently being evaluated.