medical uses of bicalutamide medical uses of bicalutamide the medical uses of bicalutamide, a nonsteroidal antiandrogen (nsaa), include the treatment of androgen-dependent conditions and hormone therapy to block the effects of androgens. indications for bicalutamide include the treatment of prostate cancer in men, skin and hair conditions such as acne, seborrhea, hirsutism, and pattern hair loss in women, high testosterone levels in women, hormone therapy in transgender women, as a puberty blocker to prevent puberty in transgender girls and to treat early puberty in boys, and the treatment of long-lasting erections in men. it may also have some value in the treatment of paraphilias and hypersexuality in men. prostate cancer bicalutamide is used primarily in the treatment of early and advanced prostate cancer. it is approved at a dosage of 50 mg/day as a combination therapy with a gonadotropin-releasing hormone analogue (gnrh analogue) or orchiectomy (that is, surgical or medical castration) in the treatment of stage d2 metastatic prostate cancer (mpc), and as a monotherapy at a dosage of 150 mg/day for the treatment of stage c or d1 locally advanced prostate cancer (lapc). although effective in mpc and lapc, bicalutamide is no longer indicated for the treatment of localized prostate cancer (lpc) due to negative findings in the early prostate cancer (epc) clinical trial programme. prior to the introduction of the newer nsaa enzalutamide in 2012, bicalutamide was considered to be the standard-of-care antiandrogen in the treatment of prostate cancer, and still remains widely used for this indication. compared to earlier antiandrogens like the steroidal antiandrogen (saa) cyproterone acetate (cpa) and the nsaas flutamide and nilutamide, bicalutamide shows an improved profile of effectiveness, tolerability, and safety, and for this reason has largely replaced them in the treatment of prostate cancer. in the early 1940s, it was discovered that growth of prostate cancer in men regressed with surgical castration or high-dose estrogen therapy, which produced very low levels of circulating testosterone, and accelerated with the administration of exogenous testosterone. it has since been elucidated that androgens like testosterone and dihydrotestosterone (dht) function as trophic factors for the prostate gland, stimulating cell division and proliferation and producing tissue growth and glandular enlargement, which, in the context of prostate cancer, results in stimulation of tumors and a considerable acceleration of disease progression. as a result of these discoveries, androgen deprivation therapy (adt), via a variety of modalities including surgical castration, high-dose estrogens, saas, gnrh analogues, nsaas, and androgen biosynthesis inhibitors (e.g., abiraterone acetate), has become the mainstay of treatment for prostate cancer. although adt can shrink or stabilize prostate tumors and hence significantly slow the course of prostate cancer and prolong life, it is not generally curative. while effective in slowing the progression of the disease initially, most advanced prostate cancer patients eventually become resistant to adt and prostate cancer growth starts to accelerate again, in part due to progressive mutations in the androgen receptor (ar) that result in the transformation of drugs like bicalutamide from ar antagonists to agonists. a few observations form the basis of the reasoning behind combined androgen blockade (cab), in which castration and an nsaa are combined. it has been found that very low levels of androgens, as in castration, are able to significantly stimulate growth of prostate cancer cells and accelerate disease progression. although castration ceases production of androgens by the gonads and reduces circulating testosterone levels by about 95%, low levels of androgens continue to be produced by the adrenal glands, and this accounts for the residual levels of circulating testosterone. moreover, it has been found that prostate gland levels of dht, which is the major androgen in the prostate, remain at 40 to 50% of their initial values following castration. this has been determined to be due to uptake of circulating weak adrenal androgens like dehydroepiandrosterone (dhea) and androstenedione (a4) by the prostate and their de novo transformation into testosterone and dht. as such, a considerable amount of androgen signaling continues within the prostate gland even with castration. in the past, surgical adrenalectomy and early androgen biosynthesis inhibitors like ketoconazole and aminoglutethimide were successfully employed in the treatment of castration-resistant prostate cancer. however, adrenalectomy is an invasive procedure with high morbidity, ketoconazole and aminoglutethimide have relatively high toxicity, and both treatment modalities require supplementation with corticosteroids, making them in many ways unideal. the development of cab with nsaas like bicalutamide and enzalutamide and with newer and more tolerable androgen biosynthesis inhibitors like abiraterone acetate has since allowed for non-invasive, convenient, and well-tolerated therapies that have replaced the earlier modalities. subsequent clinical research has found that monotherapy with higher dosages of nsaas than those used in cab is roughly equivalent to castration in extending life in men with prostate cancer. moreover, nsaa monotherapy is overall better tolerated and associated with greater quality of life than is castration, which is thought to be related to the fact that testosterone levels do not decrease with nsaa monotherapy and hence by extension that levels of biologically active and beneficial metabolites of testosterone such as estrogens and neurosteroids are preserved. for these reasons, nsaa monotherapy has become an important alternative to castration and cab in the treatment of prostate cancer. bicalutamide may be used to reduce the effects of the testosterone flare at the initiation of gnrh agonist therapy. the combination of bicalutamide with an estrogen such as ethinylestradiol sulfonate has been used as a form of cab and as an alternative to the combination of bicalutamide with surgical or medical castration. skin and hair conditions