Faslodex (fulvestrant) for Breast Cancer: What to Expect, Side Effects, and More

If you’ve been through menopause and are diagnosed with hormone receptor-positive, HER2-negative breast cancer that has spread to tissue near or away from the breast (called advanced-stage), you may be prescribed Faslodex (chemical name: fulvestrant) as your first treatment for the cancer. Faslodex is a selective estrogen receptor degrader (SERD). The medicine may also be used as a second treatment if the breast cancer grows after treatment with a different hormonal therapy medicine. If you haven't been through menopause, your doctor may prescribe medications to induce menopause along with Faslodex.

Faslodex is also used in combination with other targeted therapy medicines to treat advanced-stage, hormone receptor-positive, HER2-negative breast cancer:

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  For post-menopausal women, Faslodex and Kisqali can be used as a first treatment or as a second-line treatment

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  For pre- or post-menopausal women, Faslodex in combination with either Ibrance or Verzenio

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  For post-menopausal women with a PIK3CA mutation that has grown after hormonal therapy, Faslodex may be used with Piqray, Itovebi, or Truqap  

See Faslodex prescribing information.

Faslodex blocks the effects of estrogen on hormone receptor-positive breast cancer cells by sitting in the estrogen receptors on the cells. If Faslodex is in the receptor, estrogen can’t attach to the cancer cell and the cell doesn’t receive estrogen’s signals to grow and multiply.

Faslodex also changes the shape of the estrogen receptors so they don’t work as well.

Each Faslodex treatment is made up of two injections, one into each butt cheek. Each injection takes about one to two minutes. You receive the injections on days one, 15, and 29 of treatment of the first month of treatment, and then once per month after that.

Members of our community have shared that you can ask your nurse to warm up the Faslodex shot in their hands prior to injection to lessen the pain.

If you have severe liver problems, you’ll likely get only one injection at each treatment.

Like almost all breast cancer medicines, Faslodex can cause side effects, some of them severe.

The most common side effects of Faslodex are:

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  injection site pain

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  nausea

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  bone pain

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  muscle pain

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  headache

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  back pain

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  fatigue

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  hot flashes

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  vomiting

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  loss of appetite

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  weakness

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  cough

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  difficulty breathing

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  constipation

Faslodex also may cause serious side effects, including:

Bleeding problems: Faslodex can increase the risk of bleeding. If you take blood thinners or have a history of blood clots or bleeding disorders, this risk may be much higher than average. Tell your doctor right away if you notice that a cut doesn’t stop bleeding.

You should not receive Faslodex if you are breastfeeding, pregnant, trying to get pregnant, or if there is any chance that you could be pregnant. Faslodex may cause birth defects in an unborn child. You should use an effective non-hormonal type of birth control while you are taking Faslodex and for one year after your last dose of the medicine. Ask your doctor which type of non-hormonal birth control would be best for you.

Members of our community discuss their experiences with Faslodex in the community forum. Here are some of their comments. Remember, it's essential to talk to your doctor about any side effects you're having and ask about ways to manage them.

“I just had my 3rd loading dose of Faslodex and I'm ready to be on the once-a-month schedule! So far the only side effects are the achy hips and pelvis, which is quite sore and noticeable all the time, and also the hot flashes seem a bit more severe though not more frequent.” —Checka

“About 10-14 days after the Faslodex shots, side effects seem to emerge: myalgia (back and legs), hot flashes, a bit nauseous, and slight headache. Then in the fourth week, the side effects have subsided.” —meja

“I have no side effects from Faslodex whatsoever.” —gailmary

Read more in our Faslodex discussion forum.

The cost of Faslodex may vary. The price you’ll pay depends on the drug manufacturer, your health insurance provider and plan, where you live, and the pharmacy you use. 

Note: Your insurance company may require you to get prior authorization before covering Faslodex. 

If your doctor prescribes Faslodex and you have problems paying for it or getting it covered by insurance, the AstraZeneca Access 360 program may be able to help you. There is also a generic version of Faslodex available.

Learn more about financial assistance and medicine cost-lowering tips.