trengestone trengestone trengestone, sold under the brand names reteroid, retroid, and retrone, is a progestin medication which was formerly used to treat menstrual disorders but is now no longer marketed. it is taken by mouth. trengestoneclinical datatrade namesreteroid, retroid, retroneother namesro 4-8347; triengestone; 1,6-didehydro-6-chlororetroprogesterone; 6-chloro-9β-10α-pregna-1,4,6-triene-3,20-dioneroutes ofadministrationby mouthdrug classprogestogen; progestinatc codenonelegal statuslegal status in general: ℞ (prescription only) pharmacokinetic databioavailability≥41–46% (based on urinary excretion)metabolismlivermetabolites• 20α-dihydrotrengestoneelimination half-life• trengestone: very short• 20α-dhtg: 8–14 hoursexcretionurine: 41–46%feces: 30% (unchanged)identifiers iupac name (8s,9s,10r,13s,14s,17s)-17-acetyl-6-chloro-10,13-dimethyl-8,9,11,12,14,15,16,17-octahydrocyclopentaphenanthren-3-one cas number5192-84-7pubchem cid56840930chemspider28475379uniivy6s496svxchebichebi:135458chemblchembl2107518echa infocard100.023.617 chemical and physical dataformulac21h25clo2molar mass344.88 g·mol−13d model (jsmol)interactive image smiles cc(=o)1cc21(cc32c=c(c4=cc(=o)c=c34c)cl)c inchi inchi=1s/c21h25clo2/c1-12(23)15-4-5-16-14-11-19(22)18-10-13(24)6-8-21(18,3)17(14)7-9-20(15,16)2/h6,8,10-11,14-17h,4-5,7,9h2,1-3h3/t14-,15+,16-,17-,20+,21+/m0/s1key:usxvmpawzooyde-hguqnlgysa-n side effects of trengestone include headache, fatigue, and breast tenderness among others. trengestone is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. it is not androgenic or estrogenic. trengestone was introduced for medical use in 1974. it is no longer available. medical uses trengestone was used in the treatment of menstrual disorders. it has also been used to induce ovulation, with about a 50% success rate on average. side effects