Antiandrogens are used to treat an assortment of androgen-dependent conditions.
In males, antiandrogens are used in the treatment of prostate cancer, enlarged prostate, scalp hair loss, overly high sex drive, unusual and problematic sexual urges, and early puberty.
Monotherapy with the nonsteroidal antiandrogen bicalutamide is also used in the treatment of prostate cancer as an alternative to castration with comparable effectiveness but with a different and potentially advantageous side effect profile.
Steroidal AR antagonists tend to have off-target hormonal actions due to their structural similarity to other steroid hormones.Although they are described as antiandrogens and indeed show only such effects generally, most or all steroidal AR antagonists are actually not silent antagonists of the AR but rather are weak partial agonists and are able to activate the receptor in the absence of more potent AR agonists like testosterone and DHT.These side effects include breast pain/tenderness and gynecomastia (breast development/enlargement), reduced body hair growth/density, decreased muscle mass and strength, feminine changes in fat mass and distribution, and reduced penile length and testicular size.In addition, antiandrogens can cause infertility, osteoporosis, hot flashes, sexual dysfunction (including loss of libido and erectile dysfunction), depression, fatigue, anemia, and decreased semen/ejaculate volume in males.The side effects of antiandrogens vary depending on the type of antiandrogen – namely whether it is a selective AR antagonist or lowers androgen levels – as well as the presence of off-target activity in the antiandrogen in question.
For instance, whereas antigonadotropic antiandrogens like Gn RH analogues and cyproterone acetate are associated with pronounced sexual dysfunction and osteoporosis in men, selective AR antagonists like bicalutamide are not associated with osteoporosis and have been associated with only minimal sexual dysfunction.In women who are pregnant, antiandrogens can interfere with the androgen-mediated sexual differentiation of the genitalia and brain of male fetuses.This manifests primarily as ambiguous genitalia – that is, undervirilized or feminized genitalia which, anatomically, are a cross between a penis and a vagina – and theoretically also as femininity and homosexuality.Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs which prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body.They act by blocking the androgen receptor (AR) and/or inhibiting or suppressing androgen production.Although antiandrogens are effective in slowing the progression of prostate cancer, they are not generally curative, and with time, the disease adapts and androgen deprivation therapy eventually becomes ineffective.