ratio of anabolic to androgenic activity, similarly to other nandrolone derivatives. Like other 17α-alkylated AAS, ethylestrenol has a risk of hepatotoxicity. Pharmacokinetics Ethylestrenol has very low affinity for human serum sex hormone-binding globulin (SHBG), less than 5% of that of testosterone and less than 1% of that of DHT. It is known to be metabolized into the closely related AAS norethandrolone (17α-ethyl-19-nortestosterone) in the body and has been regarded as a prodrug of norethandrolone. This is in accordance with its very low affinity for the androgen receptor, only about 5% of that of testosterone and 2% of that of dihydrotestosterone. Chemistry Ethylestrenol, also known as 3-deketo-17α-ethyl-19-nortestosterone or as 17α-ethylestr-4-en-17β-ol, is a synthetic estrane steroid and a 17α-alkylated derivative of nandrolone (19-nortestosterone; 19-NT). It is specifically the 17α-ethyl and 3-deketo derivative of nandrolone as well as the 3-deketo derivative of norethandrolone (17α-ethyl-19-NT). Other related AAS include bolenol (3-deketo-17α-ethyl-19-nor-5-androstenediol), ethyldienolone (17α-ethyl-δ9-19-NT), norboletone (17α-ethyl-18-methyl-19-NT), propetandrol (17α-ethyl-19-NT 3β-propionate), and tetrahydrogestrinone (THG; 17α-ethyl-18-methyl-δ9,11-19-NT). The progestins allylestrenol (3-deketo-17α-allyl-19-NT) and lynestrenol (3-deketo-17α-ethynyl-19-NT) are also closely related to ethylestrenol, differing only by the C17α substitution. History Ethylestrenol was described in the literature in 1959 and approved for medical use in 1961 and in the United States in 1964. Society and culture Generic names Ethylestrenol is the generic name of the drug and its , , and , while éthylestrénol is its and ethylnandrol is its . The was formerly ethyloestrenol, but it was eventually changed. Brand names Ethylestrenol is or has been marketed under a variety of brand names including Durabolin O, Duraboral, Fertabolin, Maxibolin, Maxibolin Elixir, Orabolin, Orgabolin, Orgaboral, and Virastine. The brand name Durabolin O is a contraction of "Durabolin Oral", Durabolin being a brand name of the nandrolone ester nandrolone phenylpropionate. Ethylestrenol is or has also been marketed for veterinary use under the brand names Nandoral, Nitrotain, and Oestrotain. Availability The availability of ethylestrenol is very limited. It appears to be available only in Australia and New Zealand and in these countries only for veterinary use. Legal status Ethylestrenol, along with other AAS, is a schedule III controlled substance in the United States under the Controlled Substances Act. References External links Abandoned drugs 1-Ethylcyclopentanols Androgens and anabolic steroids Estranes Hepatotoxins Prodrugs Progestogens Synthetic estrogens Veterinary drugs World Anti-Doping Agency prohibited substances