zanoterone zanoterone zanoterone (inn, usan) (former developmental code name win-49596), also known as (5α,17α)-1'-(methylsulfonyl)-1'-h-pregn-20-ynopyrazol-17-ol, is a steroidal antiandrogen which was never marketed. it was investigated for the treatment of benign prostatic hyperplasia (bph) but failed to demonstrate sufficient efficacy in phase ii clinical trials, and also showed an unacceptable incidence rate and severity of side effects (e.g., breast pain and gynecomastia). as such, it was not further developed. zanoteroneclinical dataother nameswin-49596; (5α,17α)-1'-(methylsulfonyl)-1'-h-pregn-20-ynopyrazol-17-olroutes ofadministrationby mouthdrug classsteroidal antiandrogenidentifiers iupac name (1r,3as,3br,5as,10as,10bs,12as)-1-ethynyl-10a,12a-dimethyl-8-(methylsulfonyl)-1,2,3,3a,3b,4,5,5a,6,8,10,10a,10b,11,12,12a-hexadecahydrocyclopentanaphthoindazol-1-ol cas number107000-34-0pubchem cid9844827drugbankd06357chemspider8020541uniixq5v1w49jgkeggd06357chemblchembl2079581comptox dashboard (epa)dtxsid50147873 chemical and physical dataformulac23h32n2o3smolar mass416.58 g·mol−13d model (jsmol)interactive image smiles c12cc3(1cc2(c#c)o)cc43(cc5=cn(n=c5c4)s(=o)(=o)c)c inchi inchi=1s/c23h32n2o3s/c1-5-23(26)11-9-19-17-7-6-16-12-20-15(14-25(24-20)29(4,27)28)13-21(16,2)18(17)8-10-22(19,23)3/h1,14,16-19,26h,6-13h2,2-4h3/t16-,17+,18-,19-,21-,22-,23-/m0/s1key:mhddzdpnidvlnk-zgiwmxsjsa-n zanoterone was derived from 5α-dihydroethisterone (5α-dihydro-17α-ethynyltestosterone). it is an antagonist of the androgen receptor (ki = 2.2 μm; rba compared to metribolone = 2.2%), and with the exception of antiprogestogenic activity in rat and rabbit models, is devoid of other hormonal activities. zanoterone does not inhibit 5α-reductase, aromatase, or 3α- or 3β-hydroxysteroid dehydrogenase in vitro. the drug significantly increases testosterone and estradiol levels in men. zanoterone has been found to not significantly inhibit mating performance or fertility in adult male rats at high dosages for an extended period of time. it has been found to act as an inducer of the enzyme cyp3a4 in vivo in rats. relative potencies of selected antiandrogens antiandrogenrelative potency bicalutamide4.3 hydroxyflutamide3.5 flutamide3.3 cyproterone acetate1.0 zanoterone0.4 description: relative potencies of orally administered antiandrogens in antagonizing 0.8 to 1.0 mg/kg s.c. testosterone propionate-induced ventral prostate weight increase in castrated immature male rats. higher values mean greater potency. sources: see template.