Raloxifene hydrochloride

Abstract

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and therapeutic role of raloxifene hydrochloride are reviewed. Raloxifene is a selective estrogen-receptor modulator (SERM) that has been approved for use in the prevention and treatment of osteoporosis in postmenopausal women. A SERM interacts with estrogen receptors, functioning as an agonist in some tissues and an antagonist in other tissues. Because of their unique pharmacologic properties, these agents can achieve the desired effects of estrogen without the possible stimulatory effects on the breasts or uterus. Raloxifene is rapidly absorbed from the gastrointestinal tract and undergoes extensive first-pass glucuronidation. Approximately 60% of a dose is absorbed; however, absolute bioavailability is only 2%. The volume of distribution is 2348 L/kg for a single oral dose of 30-150 mg, and the elimination half-life averages 32.5 hours. In clinical trials in postmenopausal women, raloxifene had an estrogen-like effect on bone turnover and increased bone mineral density. It reduced the risk of fractures in women with osteoporosis. Raloxifene also seemed to reduce the risk of breast cancer and positively influenced blood lipid markers of cardiovascular disease. Raloxifene is generally well tolerated; the most common adverse effects are hot flashes and leg cramps. A serious adverse effect is venous thromboembolism. The recommended dosage is 60 mg/day orally without regard to meals. Ultimately, it will be information on cardiovascular or breast cancer benefits that will determine the future role of raloxifene. Raloxifene is an alternative to traditional hormone replacement therapy for the prevention and treatment of osteoporosis in selected postmenopausal women. More study is needed to verify possible benefits related to heart disease and breast cancer.