5Î±-reductase inhibitors (5-aris) are a class of drugs with antiandrogen effects, used primarily in the treatment of benign prostatic hyperplasia (bph) and androgenic alopecia. these agents inhibit the enzyme 5Î±-reductase, which is involved in the metabolic transformations of a variety of endogenous steroids. 5Î±-reductase inhibition is most known for preventing conversion of testosterone, the major androgen sex hormone, to the more potent dihydrotestosterone (dht), in androgen-associated disorders. ==medical use==   5-aris are clinically used in the treatment of conditions that are exacerbated by dht:rossi s (ed.) (2004). australian medicines handbook 2004. adelaide: australian medicines handbook. isbn 0-9578521-4-2 * mild-to-moderate benign prostatic hyperplasia and lower urinary tract symptoms * androgenic alopecia in both men and women they have also been explored in the treatment and prevention of prostate cancer. however, their use for this indication is controversial, as some authors have expressed concern that they may inadvertently lead to development of more aggressive tumor variants. 5-aris are also sometimes employed as supplementary antiandrogens in hormone replacement therapy for trans women. ==adverse reactions== in general, adverse drug reactions (adrs) experienced with 5-aris are dose-dependent. common adrs include impotence, decreased libido, decreased ejaculate volume, depression, and anxiety. rare adrs include breast tenderness and enlargement (gynecomastia), and allergic reaction. the fda has notified healthcare professionals that the warnings and precautions section of the labels for the 5-ari class of drugs has been revised to include new safety information about the increased risk of being diagnosed with a more serious form of prostate cancer (high-grade prostate cancer). finasteride is associated with intraoperative floppy iris syndrome and cataract formation. ==pharmac
5-alpha-reductase_inhibitors