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.
Food and Drug Administration
National Cancer Institute
Faslodex—fulvestrant injection. DailyMed website. Available at: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=83d7a440-e904-4e36-afb5-cb02b1c919f7. Updated May 19, 2016. Accessed June 15, 2016.
Fulvestrant. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 6, 2016. Accessed June 15, 2016.
Hormone therapy for breast cancer. American Cancer Society website. Available at: http://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-treating-hormone-therapy. Updated May 4, 2016. Accessed June 15, 2016.
Last reviewed June 2016 by Michael Woods, MD Last Updated: 6/15/2016