Tamoxifen is a prescription medication used to treat breast cancer and lower the the chance of developing breast cancer. Certain types of breast cancers need estrogen to grow. Tamoxifen belongs to a group of drugs called anti-estrogens, which can block estrogen’s effects, slowing the growth of cancer cells. 

This medication comes in tablet form and is usually taken once or twice a day.

Common side effects of Tamoxifen include hot flashes and vaginal discharge.