lynestrenol lynestrenol lynestrenol, sold under the brand names exluton and ministat among others, is a progestin medication which is used in birth control pills and in the treatment of gynecological disorders. the medication is available both alone and in combination with an estrogen. it is taken by mouth. lynestrenolclinical datatrade namesexluton, ministat, othersother nameslinestrenol; lynenol; nsc-37725; 17α-ethynylestr-4-en-17β-ol; 19-nor-17α-pregn-4-en-20-yn-17-olahfs/drugs.cominternational drug namesroutes ofadministrationby mouthdrug classprogestogen; progestinatc codeg03ac02 (who) g03dc03 (who);g03aa03 (who) g03ab02 (who) g03fa07 (who) g03fb02 (who) (combinations with estrogens)identifiers iupac name (8r,9s,10r,13s,14s,17r)-17-ethynyl-13-methyl-2,3,6,7,8,9,10,11,12,14,15,16-dodecahydro-1h-cyclopentaphenanthren-17-ol cas number52-76-6 ypubchem cid5857chemspider5648 yuniin2z8alg4u5keggd01580 ycomptox dashboard (epa)dtxsid4021478 echa infocard100.000.139 chemical and physical dataformulac20h28omolar mass284.443 g·mol−13d model (jsmol)interactive image smiles c#c2(o)cc14(cc12c)3\c(=c/ccc3)cc4 inchi inchi=1s/c20h28o/c1-3-20(21)13-11-18-17-9-8-14-6-4-5-7-15(14)16(17)10-12-19(18,20)2/h1,6,15-18,21h,4-5,7-13h2,2h3/t15-,16+,17+,18-,19-,20-/m0/s1 ykey:ynvgqyhlrcdxfq-xgxhktljsa-n y (verify) lynestrenol is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. it has weak androgenic and estrogenic activity and no other important hormonal activity. the medication is a prodrug of norethisterone in the body, with etynodiol occurring as an intermediate. lynestrenol was discovered in the late 1950s and was introduced for medical use in 1961. it has mostly been used in europe and elsewhere in the world and was never marketed in the united states. medical uses lynestrenol is used as a component of oral contraceptives in combination with an estrogen and is used in the treatment of gynecological disorders such as menstrual disorders. side effects main articles: norethisterone § side effects, and progestin § side effects pharmacology norethisterone (3-ketolynestrenol), the active metabolite of lynestrenol. lynestrenol itself does not bind to the progesterone receptor and is inactive as a progestogen. it is a prodrug, and upon oral administration, is rapidly and almost completely converted into norethisterone, a potent progestogen, in the liver during first-pass metabolism. no other metabolites besides norethisterone are formed from lynestrenol. as such, its pharmacological activity is essentially identical to that of norethisterone. the conversion of lynestrenol into norethisterone is catalyzed by cyp2c9 (28.0%), cyp2c19 (49.8%), and cyp3a4 (20.4%), while other cytochrome p450 enzymes are each responsible for no more than 1.0% of the total conversion. it appears that lynestrenol first undergoes hydroxylation of the c3 position, forming etynodiol as an intermediate, followed by oxygenation of the hydroxyl group to form norethisterone. the peak blood levels are reached within 2 to 4 hours after oral administration, 97% of the administered dose being bound to plasma proteins. lynestrenol and its metabolites are predominantly excreted in urine, less in feces, active metabolite norethisterone elimination half-life being 16 or 17 hours. the pharmacokinetics of lynestrenol have been reviewed. relative affinities (%) of norethisterone, metabolites, and prodrugs compoundtypeaprarergrmrshbgcbg norethisterone–67–751500–10–3160 5α-dihydronorethisteronemetabolite252700 ? ? ? 3α,5α-tetrahydronorethisteronemetabolite100–10 ? ? ? 3α,5β-tetrahydronorethisteronemetabolite ?00 ? ? ? ? 3β,5α-tetrahydronorethisteronemetabolite100–80 ? ? ? ethinylestradiolmetabolite15–251–31121–300.180 norethisterone acetateprodrug205100 ? ? norethisterone enanthateprodrug ? ? ? ? ? ? ? noretynodrelprodrug6020000 etynodiolprodrug1011–180 ? ? ? etynodiol diacetateprodrug10000 ? ? lynestrenolprodrug11300 ? ? notes: values are percentages (%). reference ligands (100%) were promegestone for the pr, metribolone for the ar, estradiol for the er, dexamethasone for the gr, aldosterone for the mr, dihydrotestosterone for shbg, and cortisol for cbg. footnotes: a = active or inactive metabolite, prodrug, or neither of norethisterone. sources: see template. chemistry