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. 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. Tamoxifen, sold under the brand name Nolvadex among others, is a selective estrogen receptor modulator used to prevent breast cancer in women and men. [15] It is also being studied for other types of cancer. [15] It has been used for Albright syndrome. [16] Tamoxifen is typically taken daily by mouth for five years for breast cancer. [16] Serious side effects include a small increased risk of. What should I tell my care team before I take this medication? They need to know if you have any of these conditions: Blood clots Endometriosis High cholesterol Irregular menstrual cycles Liver disease Stroke Uterine cancer Uterine fibroids An unusual reaction to tamoxifen, other medications, foods, dyes, or preservatives Pregnant or trying to get pregnant Breast-feeding Tamoxifene: Tamoxifen belongs to the group of cancer-fighting medications known as antineoplastics, and specifically to the type of antineoplastics known as antiestrogens. It is used in combination with other medications to treat early breast cancer. Taking adjuvant tamoxifen for 10 years after primary treatment leads to a greater reduction in breast cancer recurrences and deaths than taking the drug for only 5 years, according to the results of a large international clinical trial. Tamoxifen, an antiestrogen, is a potent drug to treat and prevent hormone dependent breast cancer. As it has low toxicity and is widely available, tamoxifen has become one of the most frequently prescribed anticancer drugs worldwide. A major side. While some antidepressants may affect the metabolism of tamoxifen into its active form, many antidepressants can be used safely in this population. Read on for tamoxifen dosage information for breast cancer, including typical dosages, adjustments for health conditions, and what to do if you miss a dose. Tamoxifen (brand names: Nolvadex, Soltamox) is a medicine that blocks the effects of the hormone estrogen (called a selective estrogen receptor modulator, or SERM). Tamoxifen is a first choice among doctors for treating women who have not yet gone through menopause. The medicine can also be prescribed to women who have gone through menopause and to men.