Raloxifene

Raloxifene, sold under the brand name Evista among others, is a medication used to prevent and treat osteoporosis in postmenopausal women and those on glucocorticoids. For osteoporosis it is less preferred than bisphosphonates. It is also used to reduce the risk of breast cancer in those at high risk. It is taken by mouth.

Common side effects include hot flashes, leg cramps, swelling, and joint pain. Severe side effects may include blood clots and stroke. Use during pregnancy may harm the baby. The medication may worsen menstrual symptoms. Raloxifene is a selective estrogen receptor modulator (SERM) and therefore a mixed agonist–antagonist of the estrogen receptor (ER). It has estrogenic effects in bone and antiestrogenic effects in the breasts and uterus.

Raloxifene was approved for medical use in the United States in 1997. It is available as a generic medication. In 2020, it was the 292nd most commonly prescribed medication in the United States, with more than 1 million prescriptions.

Raloxifene is used for the treatment and prevention of osteoporosis in postmenopausal women. It is used at a dosage of 60 mg/day for both the prevention and treatment of osteoporosis. In the case of either osteoporosis prevention or treatment, supplemental calcium and vitamin D should be added to the diet if daily intake is inadequate.

Raloxifene is used to reduce the risk of breast cancer in postmenopausal women. It is used at a dosage of 60 mg/day for this indication. In the Multiple Outcomes of Raloxifene (MORE) clinical trial, raloxifene decreased the risk of all types of breast cancer by 62%, of invasive breast cancer by 72%, and of invasive estrogen receptor-positive breast cancer by 84%. Conversely, it does not reduce the risk of estrogen receptor-negative breast cancer. There were no obvious differences in effectiveness of raloxifene in the MORE trial for prevention of breast cancer at a dosage of 60 mg/m²/day relative to 120 mg/m²/day. In the Study of Tamoxifen and Raloxifene (STAR) trial, 60 mg/day raloxifene was 78% as effective as 20 mg/day tamoxifen in preventing non-invasive breast cancer. Women with undetectable levels of estradiol (<2.7 pg/mL) have a naturally low risk of breast cancer and, in contrast to women with detectable levels of estradiol, do not experience significant benefit from raloxifene in terms of reduction of breast cancer risk.

Raloxifene is contraindicated in lactating women or women who are or who may become pregnant. It also may be of concern to women with active or past history of venous thromboembolic events, including deep vein thrombosis, pulmonary embolism, and retinal vein thrombosis.

Common side effects of raloxifene include hot flashes (25–28% vs. 18–21% for placebo), vaginal dryness, and leg cramps (generally mild; 5.5% vs. 1.9% for placebo). Raloxifene does not cause breast tenderness, endometrial hyperplasia, menstrual bleeding, or endometrial cancer. It does not appear to affect cognition or memory. Raloxifene is a teratogen; i.e., it can cause developmental abnormalities such as birth defects.^{[citation needed]}

Raloxifene may infrequently cause serious blood clots to form in the legs, lungs, or eyes. Other reactions experienced include leg swelling/pain, trouble breathing, chest pain, and vision changes. Black box warnings were added to the label of raloxifene in 2007 warning of increased risk of death due to stroke for postmenopausal women with documented coronary heart disease or at increased risk for major coronary events, as well as increased risk for deep vein thrombosis and pulmonary embolism. The risk of venous thromboembolism with raloxifene is increased by several-fold in postmenopausal women (RRTooltip relative risk = 3.1). Raloxifene has a lower risk of thromboembolism than tamoxifen. In the MORE trial, raloxifene caused a 40% decrease in risk of cardiovascular events in women who were at increased risk for coronary artery disease, although there was no decrease in cardiovascular events for the group as a whole.