Femara is approved for certain types of breast cancer in postmenopausal women. For example, the drug can be used to treat early breast cancer that is hormone receptor-positive post-surgery and advanced breast cancer that is either hormone receptor-positive or for which the hormone receptor is unknown. Femara comes in tablet form, and is typically taken once a day. Side effects include hot flashes, night sweats, and weight gain.
What Is Femara?Femara® (letrozole) is a prescription medication used to treat breast cancer in postmenopausal women. Specifically, the drug has been licensed to treat postmenopausal women who:
- Have early breast cancer that is hormone receptor-positive and who have had surgery
- Have taken tamoxifen (Nolvadex®, Soltamox™) for five years after surgery or radiation therapy for breast cancer
- Have advanced or metastatic (spreading) breast cancer that is either hormone receptor-positive or hormone receptor-unknown.
(Click Femara Uses for more information on what the drug is used for, including possible off-label uses.)
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. These enzymes help produce estrogens (in particular, a certain estrogen called estradiol). In postmenopausal women, most of the estrogen in the body is made by aromatase. 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. This type of breast cancer treatment is known as hormonal therapy (see Breast Cancer Hormone Treatment).