How Does Femara Work?Femara is part of a group of medications called aromatase inhibitors. Aromatase is an enzyme found in various places in the body. It helps with the production of estrogens (in particular, a certain estrogen called estradiol). In postmenopausal women, most of the estrogen in the body is made by aromatase enzymes. By blocking these enzymes, Femara helps to decrease the amount of estrogen in the body.
Many breast cancers are sensitive to the estrogen hormone, meaning that the tumor grows with its help. When a tumor is sensitive to estrogen, it has receptors on the outer surface of its cells, into which estrogen fits like a key opening a lock. When this connection is made, the cancer grows. Breast cancers that have estrogen (and/or progesterone) receptors are known as hormone receptor-positive tumors.
By decreasing estrogen production, Femara can help decrease the growth of these breast cancers.