Tamoxifen is a drug, taken by mouth as a pill.
It has been used for more than 20 years to treat patients with breast cancer. Tamoxifen works against breast cancer, in part, by interfering with the activity of estrogen, a female hormone that promotes the growth of breast cancer cells. Raloxifene is a drug, taken by mouth as a pill. In December 1997, it was approved by the FDA for the prevention of osteoporosis in postmenopausal women. Raloxifene is being studied because large studies testing its effectiveness against osteoporosis have shown that women taking the drug developed fewer breast cancers than women taking the placebo.