abiraterone acetate
Abiraterone acetate (Zytiga) is an oral medicine that lowers the body's production of androgens by blocking an enzyme needed to make testosterone. It is used with prednisone to treat metastatic castration-resistant and castration-sensitive prostate cancer.
This page is based on FDA prescribing information for abiraterone acetate tablets, cross-checked with the National Cancer Institute drug dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
Prostate cancer cells often feed on testosterone to grow. Abiraterone acts like a roadblock on the factory line that builds testosterone, shutting down production at the source — in the testes, the adrenal glands, and even inside the tumor itself — so the cancer cells are starved of the fuel they need.
In simple terms
Abiraterone blocks an enzyme called CYP17A1 that the body uses to make testosterone and other androgens. Even when standard hormone therapy lowers testosterone from the testes, the adrenal glands and the prostate tumor itself can still produce small amounts of androgens that help cancer cells grow. By blocking CYP17A1 everywhere in the body, abiraterone reduces androgen levels to very low levels, slowing or stopping the growth of prostate cancer cells. It is always taken together with prednisone, which helps reduce certain side effects.
In depth
Abiraterone acetate is an orally active prodrug of abiraterone, which irreversibly inhibits the enzyme CYP17A1 (steroid 17α-monooxygenase, a member of the cytochrome P450 family). CYP17A1 catalyzes two sequential reactions — 17α-hydroxylation of pregnenolone and progesterone, and C17,20 lyase cleavage of 17α-hydroxypregnenolone and 17α-hydroxyprogesterone to form dehydroepiandrosterone (DHEA) and androstenedione — that are required for androgen biosynthesis. By blocking both activities, abiraterone suppresses androgen production not only from the testes but also from the adrenal glands and from within prostate tumor tissue itself. This reduces circulating and intratumoral testosterone and other androgens to castrate-range levels, suppressing androgen-receptor signaling in prostate cancer cells. Prednisone is co-administered to suppress ACTH-driven mineralocorticoid excess caused by upstream steroid shunting.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How abiraterone blocks the factory that builds testosterone
- Prostate cancer cells often feed on testosterone to grow.
- Abiraterone blocks an enzyme called CYP17A1 that the body uses to make testosterone and other androgens.
- Even when standard hormone therapy lowers testosterone from the testes, the adrenal glands and the prostate tumor itself can still produce small amounts of androgens that help cancer cells grow.
- By blocking CYP17A1 everywhere in the body, abiraterone reduces androgen levels to very low levels, slowing or stopping the growth of prostate cancer cells.
Target: CYP17A1 (steroid 17α-monooxygenase)
A cytochrome P450 enzyme that catalyzes two reactions (17α-hydroxylase and C17,20 lyase) required for androgen biosynthesis in the testes, adrenal glands, and prostate tumor tissue; abiraterone blocks both activities.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- Treatment of patients with metastatic castration-resistant prostate cancer, in combination with prednisone.
- Treatment of patients with metastatic high-risk castration-sensitive prostate cancer, in combination with prednisone.
Official sources
The statements on this page trace back to these records.
- U.S. Food and Drug Administration: abiraterone acetate prescribing information
U.S. Food and Drug Administration
- National Cancer Institute: abiraterone acetate
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.