Anti-estrogens are medications that block or reduce the effects of estrogen in the body. Estrogen is an important hormone for the development and function of female reproductive organs. Still, it can also play a role in developing certain cancers, such as breast cancer. Anti-estrogens are often used in treating breast cancer and other conditions where reducing estrogen levels is beneficial.

There are several different types of anti-estrogens, including:

    Selective estrogen receptor modulators (SERMs): These medications block the effects of estrogen in breast tissue, but may have estrogen-like effects in other parts of the body. Tamoxifen is a commonly used SERM for the treatment of breast cancer.

    Aromatase inhibitors (AIs): These medications block the production of estrogen by the body. They are often used in postmenopausal women with breast cancer. Examples of AIs include anastrozole, letrozole, and exemestane.

    Fulvestrant: This medication works by binding to and blocking the estrogen receptor, which can slow the growth of estrogen-dependent tumors.

Anti-estrogens may have side effects like hot flashes, fatigue, and mood changes. It's important to work with a healthcare provider to determine the most appropriate anti-estrogen medication and manage any possible side effects.