Steroidal antiandrogen

Steroidal antiandrogen
Drug class
Cyproterone acetate, the most widely employed steroidal antiandrogen.
Class identifiers
Synonyms	Steroidal androgen receptor antagonists
Use	Prostate cancer; Benign prostatic hyperplasia; Acne; Hirsutism; Seborrhea; Pattern hair loss; Hyperandrogenism; Transgender hormone therapy; Hypersexuality; Paraphilias; Male precocious puberty; Priapism
ATC code	G03HA
Biological target	Androgen receptor
Chemical class	Steroidal

A steroidal antiandrogen (SAA) is an antiandrogen with a steroidal chemical structure. They are typically antagonists of the androgen receptor (AR) and act both by blocking the effects of androgens like testosterone and dihydrotestosterone (DHT) and by suppressing gonadal androgen production. SAAs are used in the treatment of androgen-dependent conditions in men and women, and are also used in veterinary medicine for the same purpose. They are the converse of nonsteroidal antiandrogens (NSAAs), which are antiandrogens that are not steroids and are structurally unrelated to testosterone.

SAAs are used in clinical medicine for the following indications:

Unlike NSAAs, most SAAs show off-target hormonal activity such as progestogenic, glucocorticoid, or antimineralocorticoid activity, possess antigonadotropic effects, and are weak partial agonists of the AR with some capacity to activate the receptor. Due to their antigonadotropic effects, SAAs lower androgen levels in addition to directly blocking the actions of androgens at the AR; at sufficiently high dosages, they are able to lower circulating testosterone levels by up to 70 to 80% in men, to just above the castrate range. However, due to their other hormonal effects, suppression of estrogen levels alongside testosterone levels, and AR activation, SAAs have increased side effects and show lower efficacy in the treatment of prostate cancer relative to NSAAs.