What is Faslodex® (fulvestrant)?
Reviewed by: HU Medical Review Board | Last reviewed: June 2023 | Last updated: August 2023
Faslodex® (fulvestrant) is an estrogen receptor antagonist used to treat certain cases of hormone receptor positive (HR+) advanced or metastatic breast cancer. It is approved to treat:1,2
- HR+, human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer in women who are past menopause and have not been previously treated with endocrine therapy
- HR+ advanced breast cancer in women who are past menopause and whose disease has progressed after treatment with other endocrine therapy
- HR+, HER2- advanced breast cancer or breast cancer that has spread to other parts of the body in combination with abemaciclib or palbociclib in women whose disease has progressed after treatment with other endocrine therapy
- HR+, HER2- advanced breast cancer or breast cancer that has metastasized (spread to other parts of the body) in women who are past menopause in combination with ribociclib as initial hormone therapy or in women whose disease has progressed after treatment with other hormone therapy
What are the ingredients in Faslodex?
The active ingredient in Faslodex is fulvestrant.1
How does fulvestrant work?
Many breast cancers have estrogen receptors on the surface of their cells. Estrogen can connect to these receptors and stimulate the growth of these breast cancers. Fulvestrant binds to the estrogen receptor and can help block or slow the breast cancer’s growth.1
What are some of the possible side effects of fulvestrant?
The most common side effects experienced by patients receiving fulvestrant include:1,2
- Injection site pain
- Joint, muscle, or bone pain
- Back pain
- Fatigue or weakness
- Pain in the arms or legs
- Hot flashes
- Loss of appetite
- Shortness of breath
- Increases in liver enzymes
Fulvestrant may also cause nerve damage where it is injected into the buttocks. Tell your doctor if you have any signs of nerve damage in your legs, including:1,2
These are not all the possible side effects of fulvestrant. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with fulvestrant.
Things to know about fulvestrant
Before starting treatment with fulvestrant, tell your doctor if you have:1,2
- Any liver problems
- Problems with bleeding and/or low platelet levels
Fulvestrant can harm an unborn baby. If you can become pregnant, you should use birth control during treatment and for some time after the last dose of fulvestrant. You should also not breastfeed during treatment with fulvestrant and for some time after the last dose. Talk to your doctor about your options for birth control and breastfeeding while taking fulvestrant.1,2
Before beginning treatment for breast cancer, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.
For more information, read the full prescribing information of fulvestrant.