How does flutamide work in prostate cancer?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Oct 28, 2024.

Official Answer by Drugs.com

Flutamide is an anti-androgen and works by binding to androgen receptors found in prostate cancer cells. When flutamide binds to the androgen receptors and blocks the action of the male hormone such as testosterone, it can help keep the prostate cancer from growing and spreading.

Prostate cancer depends on male hormones (such as testosterone and (dihydrotestosterone) for growth. Anti-androgens block the action of the male hormones.

Flutamide does not kill the cancer directly, but has an effect on the testicles to block testosterone uptake or binding in the tissues. If the amount of testosterone in the body is reduced it is possible to slow down or shrink the cancer.

Flutamide has primarily been replaced by newer anti-androgen treatments such as bicalutamide (Casodex) and enzalutamide (Xtandi).

Some clinical practice guidelines no longer recommend the use of older anti-androgens like flutamide due to availability of newer options with better clinical data. However, they do state it may be used in patients with low disease burden or limited treatment options, if needed.

Flutamide is a capsule given by mouth three times per day and is only available as a generic drug. It is most often used in combination with a luteinizing hormone-releasing hormone (LHRH) analog. LHRH agonists help prevent the testicles from producing testosterone.

When LHRH agonists are used as primary therapy, they actually boost androgen production for a short period before they reduce production. An increase in androgens can lead to a tumor flare and symptoms (like bone pain or trouble urinating). The use of anti-androgens for a few weeks can help to block the androgen production and symptoms that can occur at the beginning of treatment with LHRH agonists.

What are the anti-androgens?

Beside flutamide, other medicines in the anti-androgen class include:

apalutamide (Erleada)
bicalutamide (Casodex)
darolutamide (Nubeqa)
enzalutamide (Xtandi)

This is not all the information you need to know about flutamide for safe and effective use and does not take the place of talking to your doctor about your treatment. Review the full flutamide information and discuss this medicine and any questions you have with your doctor or other health care provider.

References

Johnson DB, Sonthalia S. Flutamide. [Updated 2021 May 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482215/
Patient education: Treatment for advanced prostate cancer (Beyond the Basics). Revised Oct. 5, 2021. Up To Date. Accessed Nov. 5, 2021 at https://www.uptodate.com/contents/treatment-for-advanced-prostate-cancer-beyond-the-basics
Hormone Therapy for Prostate Cancer. American Cancer Society. Last revised Sept. 23, 2021. Accessed Nov. 5, 2021 at https://www.cancer.org/cancer/prostate-cancer/treating/hormone-therapy.html
Flutamide. Drug Information. Up To Date. Accessed Nov. 5, 2021 at https://www.uptodate.com/contents/flutamide-drug-information

Why has Xtandi stopped working and what do I take next?

Prostate cancer cells, like bacteria, can evolve over time and become resistant to treatments, including the hormone therapy and androgen receptor inhibitor Xtandi (enzalutamide). The cancer cells work to reprogram their environment and develop strategies that enable them to transform and survive.

If treatment with Xtandi stops working then other treatments may be offered, such as:

Chemotherapy
Immunotherapy
Targeted therapy
Radiotherapy

Stopping treatment with Xtandi may also result in an antiandrogen withdrawal response (AAWR), which can cause the cancer to stop growing or shrink for the period of time.

How long does Xtandi work?

Xtandi is typically taken until prostate cancer starts to progress or spread (metastasize), or until the patient can no longer tolerate therapy because of the side effects or adverse events it causes.

In clinical trials, Xtandi was effective at delaying the time to disease progression in men with advanced prostate cancer. In men who had not received prior treatment with chemotherapy, Xtandi was also effective at delaying the need for treatment with a cytotoxic chemotherapy agent.

In the AFFIRM trial, treatment with Xtandi extended life by almost 5 months in men with metastatic castration-resistant prostate cancer. Continue reading

Why is prednisone prescribed with Zytiga?

Zytiga is taken with prednisone to help manage side effects that might occur with this prostate cancer treatment. Zytiga blocks the production of cortisol from your adrenal glands. Prednisone helps to replace the lost cortisol that can cause side effects such as low blood potassium levels, fluid build up (edema), or high blood pressure. Continue reading

How does flutamide work in prostate cancer?

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