Anti-Androgens

What is an anti-androgen?

Anti-androgens are drugs that counteract the biological effects of the male hormone testosterone or its active metabolite DHT. They bind to the same androgen receptor as testosterone in specific cells and act as androgen receptor antagonists because they block the biological action of testosterone and DHT working through this receptor. Anti-androgens are either steroidal or non-steroidal and act in a competitive manner for the receptors.

Steroidal anti-androgens

Cyproterone is a steroidal anti-androgen that binds to the androgen receptor competing with testosterone and blocking testosterone binding to its receptor. However, cyproterone does have some biological effects, acting as a weak progestogen and glucocorticoid, which are other hormones involved in production of sex hormones like testosterone. This means that cyproterone does not prevent the production of testosterone completely but reduces the amount of testosterone produced. Cyproterone is used to treat hypersexuality (increased sex drive) and aggression in male sex offenders. It is also used to treat advanced prostate cancer.

Non-steroidal anti-androgens

Bicalutamide is a non-steroidal anti-androgen that binds to the androgen receptor but has no androgen or any other hormonal activity. It does not activate any normal testosterone actions, which means that it does not promote prostate cell growth or testosterone production. Bicalutamide is used to treat advanced prostate cancer, in combination with another medication that induces medical castration by preventing testosterone production by the testes. This blocks the stimulation by testosterone of cancer cell growth and helps slow or prevent progression of the tumour.