In women, antiandrogens are much better tolerated, and antiandrogens that work only by directly blocking androgens are associated with minimal side effects.However, because estrogens are made from androgens in the body, antiandrogens that suppress androgen production can cause low estrogen levels and associated symptoms like hot flashes, menstrual irregularities, and osteoporosis in premenopausal women.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.
5α-Reductase inhibitors like finasteride, dutasteride, and alfatradiol and the topical nonsteroidal AR antagonist topilutamide (fluridil) are approved for the treatment of pattern hair loss, also known as scalp hair loss or baldness.
In accordance, antiandrogens are used in the treatment of hypersexuality (excessively high sex drive) and paraphilias (atypical and sometimes societally unacceptable sexual interests) like pedophilia (sexual attraction to children).
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.
The earlier androgen synthesis inhibitors aminoglutethimide and ketoconazole have only limitedly been used in the treatment of prostate cancer due to toxicity concerns and have been replaced by abiraterone acetate.
In addition to active treatment of prostate cancer, antiandrogens are effective as prophylaxis (preventatives) in reducing the risk of ever developing prostate cancer.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.Hyperandrogenism is associated with virilization – that is, the development of masculine secondary sexual characteristics like male-pattern facial and body hair growth (or hirsutism), voice deepening, increased muscle mass and strength, and broadening of the shoulders, among others.Antiandrogens are used to prevent or reverse masculinization and to facilitate feminization in transgender women who are undergoing HRT and who have not undergone sex reassignment surgery or orchiectomy.Side effects of antiandrogens depend on the type of antiandrogen and the specific antiandrogen in question.