Karen Schroeder Kassel, MS, RD, MEd
Fulvestrant is approved for postmenopausal women with a certain type of breast cancer, called hormone receptor-positive metastatic breast cancer. If the cancer is not responsive to tamoxifen, then fulvestrant is an option. Fulvestrant is given once a month as a shot in the gluteal muscle.
Like the medication tamoxifen, fulvestrant is classified as anti-estrogen therapy. These drugs are designed to treat the forms of breast cancer that are sensitive to the hormone estrogen. In such cases, there are estrogen receptors on the outside of the breast cancer cells. These receptors take in estrogen, which stimulates their growth.
Each anti-estrogen drug works by a slightly different mechanism, making it possible for these drugs to be used in sequence. This means that doctors have more weapons to fight breast cancer, and they may be able to control the cancer for a longer period of time. Tamoxifen blocks estrogen from reaching the estrogen receptor in breast cancer cells. Fulvestrant blocks and destroys estrogen receptors in breast cancer cells.
The most common side effects include:
You will not be able to take fulvestrant if you:
Tell your doctor about any medications, including over-the-counter medications and herbs and supplements, before starting fulvestrant.
National Cancer Institute
US Food and Drug Administration
Canadian Cancer Society
Faslodex (fulvestrant) injection. DailyMed website. Available at:
http://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=83d7a440-e904-4e36-afb5-cb02b1c919f7. Updated November 2012. Accessed October 6, 2014.
Tamoxifen. American Cancer Society website. Available at: http://www.cancer.org/treatment/treatmentsandsideeffects/guidetocancerdrugs/fulvestrant. Updated December 27, 2012. Accessed October 6, 2014.
Fulvestrant. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed. Updated March 12, 2014. Accessed October 6, 2014.
Tamoxifen. American Cancer Society website. Available at: http://www.cancer.org/treatment/treatmentsandsideeffects/guidetocancerdrugs/tamoxifen. Updated February 11, 2010. Accessed October 6, 2014.
Last reviewed September 2014 by Michael Woods, MD
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