n. (context steroid drug English) A synthetic antiandrogen steroid used to suppress the actions of testosterone.
Cyproterone ( INN) is a steroidal, pure antiandrogen that was never marketed. An acylated derivative, cyproterone acetate, is widely used clinically as an antiandrogen and progestin. While cyproterone is sometimes used as a synonym for cyproterone acetate, what is almost always being referred to is actually cyproterone acetate and not cyproterone.
Cyproterone has approximately three-fold lower potency as an antiandrogen relative to CPA, and, unlike CPA, which is an extremely potent progestin, cyproterone is completely devoid of progestogenic activity. In clinical studies, cyproterone was found to be far less potent and effective as an antiandrogen relative to CPA, likely in significant part due to its lack of antigonadotropic action.