What is usp tamoxifen citrate commonly used for?

Endocrine therapy.: Tamoxifen is most commonly prescribed for the treatment of estrogen receptor-positive breast cancer, typically in women diagnosed prior to menopause. It may also be used to prevent breast cancer in high-risk patients. Following menopause, a class of drugs very similar to tamoxifen, called aromatase inhibitors, are preferentially used for breast cancer treatment rather than tamoxifen.

Breast cancer: Tamoxifen is an agonist or antagonist of estrogen. Since many breast cancers grow more in the presence of the hormone estrogen, one way to stop its growth is to utilize a drug such as tamoxifen.