Tamoxifen is used to treat breast cancer that has spread to other parts of the body in men and women. It is used to treat early breast cancer in women who have already been treated with surgery, radiation, and/or chemotherapy. Tamoxifen Citrate Tablets are indicated for the treatment of axillary node-negative breast cancer in women following total mastectomy or segmental mas-tectomy, axillary dissection, and breast irradiation. Tamoxifen is an antiestrogen drug used in the treatment of breast cancer. It blocks the activity of estrogen, helping to stop the growth of some tumors. Find patient medical information for Tamoxifen on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Nolvadex (tamoxifen citrate) is a nonsteroidal antiestrogen used to treat breast cancer that has spread to other parts of the body (metastatic breast cancer), to treat breast cancer in certain patients after surgery and radiation therapy, and to reduce the chances of breast cancer in high-risk patients. What Are Side Effects of Nolvadex? Tamoxifen citrate tablets are contraindicated in patients with known hypersensitivity to the drug or any of its ingredients. Reduction in Breast Cancer Incidence in High Risk Women and Women. Tamoxifen side effects Like almost all breast cancer medicines, tamoxifen can cause side effects, some of them severe. Tamoxifen causes side effects because it blocks estrogen receptors in both healthy and cancer cells, causing hormonal changes in your body. Tamoxifen citrate is a type of hormone therapy called a selective estrogen receptor modulator (or SERM). It works by binding to estrogen receptors, blocking estrogen’s effects in some tissues while mimicking its effects in others. In breast tissue, tamoxifen citrate blocks estrogen from binding to its receptors, which may prevent the growth of cancer cells. Tamoxifen citrate mimics estrogen. Tamoxifen, a triphenylethylene-derivative, nonsteroidal estrogen agonist-antagonist, is an antineoplastic agent. Tamoxifen blocks the actions of estrogen and is used to treat and prevent some types of breast cancer. Learn about side effects, interactions and indications.