Cyproterone

Cyproterone acetate (Androcur®, Cyprostat®) is an antiandrogen, i.e. it suppresses the actions of testosterone (or rather its metabolite dihydrotestosterone) on tissues. It acts by blocking the testosterone receptor. Its main indications are prostate cancer, benign prostatic hyperplasia, priapism, hypersexuality and other conditions in which androgen action maintains the disease process.

Until the development of leuprolide, cyproterone was one of the few drugs used to treat precocious puberty. It was also used in animal experimentation to investigate the actions of androgens in fetal sexual differentiation.

In addition, its acetate form (cyproterone acetate) has progestational activity (e.g. it acts like progesterone). As part of some contraceptive pills (Diane®) it decreases acne and hirsutism (male-pattern hair growth).

Side-effects in men include gynecomastia (breast gland hypertrophy) and galactorrhea (milk outflow). Erectile dysfunction is a direct result of its mode of action.