What is raloxifene?

David Slovik, MD
Endocrinology Diabetes & Metabolism
Raloxifene is one of a class of drugs known as selective estrogen receptor modulators (SERMs). Raloxifene is the only SERM currently approved for osteoporosis treatment and prevention, but others are in development. SERMs such as tamoxifen and raloxifene, which are often called "designer estrogens," have generated a great deal of interest because of their ability to mimic some of estrogen's positive effects without some of the negative consequences. Like estrogen, raloxifene slows bone loss, but it does not increase the risk for uterine cancer and protects against breast cancer.
Raloxifene is a type of medicine that is known as a selective estrogen receptor modulator (SERM). This means that, in some places in the body, it acts the same way that the hormone estrogen would act, while in other places, it blocks the effect of estrogen.

Specifically, within the bone, raloxifene acts like estrogen would: It prevents the kind of bone weakening that can lead to osteoporosis. In the breast, however, raloxifene acts as an “anti-estrogen," which means it can lower the risk of developing breast cancer for some women. Raloxifene also acts like an anti-estrogen in uterine tissue.