norethandrolone norethandrolone norethandrolone, sold under the brand names nilevar and pronabol among others, is an androgen and anabolic steroid (aas) medication which has been used to promote muscle growth and to treat severe burns, physical trauma, and aplastic anemia but has mostly been discontinued. it is still available for use in france however. it is taken by mouth. norethandroloneclinical datatrade namesnilevar, pronabolother namesnoretandrolone; cb-8022; 3-ketoethylestrenol; ethylestrenolone; 17α-ethyl-19-nortestosterone; 17α-ethylestr-4-en-17β-ol-3-one; 17α-ethyl-19-norandrost-4-en-17β-ol-3-one; ethylnandrolone; ethylnortestosteroneahfs/drugs.cominternational drug namesroutes ofadministrationby mouthdrug classandrogen; anabolic steroid; progestin; progestogenatc codea14aa09 (who) legal statuslegal status ca: schedule iv us: schedule iii identifiers iupac name (8r,9s,10r,13s,14s,17s)-17-ethyl-17-hydroxy-13-methyl-1,2,6,7,8,9,10,11,12,14,15,16-dodecahydrocyclopentaphenanthren-3-one cas number52-78-8 ypubchem cid5858chemspider5649 yuniip7w01638w6keggd07127 ycomptox dashboard (epa)dtxsid0023379 echa infocard100.000.140 chemical and physical dataformulac20h30o2molar mass302.458 g·mol−13d model (jsmol)interactive image smiles o=c4\c=c3/(2cc1((cc1(o)cc)2cc3)c)cc4 inchi inchi=1s/c20h30o2/c1-3-20(22)11-9-18-17-6-4-13-12-14(21)5-7-15(13)16(17)8-10-19(18,20)2/h12,15-18,22h,3-11h2,1-2h3/t15-,16+,17+,18-,19-,20-/m0/s1 ykey:zdhcjeigtnnemy-xgxhktljsa-n y (verify) side effects of norethandrolone include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire. it can also cause estrogenic effects like fluid retention, breast tenderness, and breast enlargement in men and liver damage. the drug is a synthetic androgen and anabolic steroid and hence is an agonist of the androgen receptor (ar), the biological target of androgens like testosterone and dihydrotestosterone (dht). it has strong anabolic effects relative to its androgenic effects. the drug also has strong progestogenic effects. norethandrolone was discovered in 1953 and was introduced for medical use in 1956. it was the first aas with a favorable separation of anabolic and androgenic effect to be marketed. the drug was mostly withdrawn in the 1980s due to concerns of liver damage. in addition to its medical use, norethandrolone has been used to improve physique and performance. the drug is a controlled substance in many countries and so non-medical use is generally illicit. medical uses norethandrolone has been used in the treatment of muscle wasting, patients with severe burns, after severe trauma, and for certain forms of aplastic anemia among other indications. side effects side effects of norethandrolone include virilization among others. it has estrogenic effects and can cause gynecomastia and fluid retention. as with all 17α-alkylated aas, long-term use of norethandrolone in high doses may result in hepatotoxicity including elevated liver enzymes and cirrhosis. pharmacology pharmacodynamics androgenic vs. anabolic activityof androgens/anabolic steroids medicationratioa testosterone~1:1 androstanolone (dht)~1:1 methyltestosterone~1:1 methandriol~1:1 fluoxymesterone1:1–1:15 metandienone1:1–1:8 drostanolone1:3–1:4 metenolone1:2–1:30 oxymetholone1:2–1:9 oxandrolone1:3–1:13 stanozolol1:1–1:30 nandrolone1:3–1:16 ethylestrenol1:2–1:19 norethandrolone1:1–1:20 notes: in rodents. footnotes: a = ratio of androgenic to anabolic activity. sources: see template. norethandrolone is an androgen and anabolic steroid and hence is an agonist of the androgen receptor, the biological target of androgens like testosterone and dihydrotestosterone. it has a high ratio of anabolic to androgenic activity. analogously to the case of nandrolone and 5α-dihydronandrolone, 5α-dihydronorethandrolone, the 5α-reduced metabolite of norethandrolone, shows diminished affinity for the androgen receptor relative to norethandrolone. this is likely related to the high ratio of anabolic to androgenic activity observed with norethandrolone. norethandrolone has relatively high estrogenic activity via transformation by aromatase into the potent estrogen ethylestradiol. it also has strong progestogenic activity. the progestogenic potency of norethandrolone is similar to that of norethisterone in terms of endometrial changes in women. in addition, norethandrolone is hepatotoxic. relative affinities of nandrolone and related steroids at the androgen receptor compoundrar (%)har (%) testosterone3838 5α-dihydrotestosterone77100 nandrolone7592 5α-dihydronandrolone3550 ethylestrenolnd2 norethandrolonend22 5α-dihydronorethandrolonend14 metribolone100110 sources: see template. pharmacokinetics the pharmacokinetics of norethandrolone have been reviewed. chemistry