|Trade names||Reteroid, Retroid, Retrone|
|Synonyms||Ro 4-8347; Triengestone; 1,6-Didehydro-6-chlororetroprogesterone; 6-Chloro-9β-10α-pregna-1,4,6-triene-3,20-dione|
|Drug class||Progestin; Progestogen|
|Bioavailability||≥41–46% (based on urinary excretion)|
|Elimination half-life||• Trengestone: very short|
• 20α-DHTG: 8–14 hours
Feces: 30% (unchanged)
|Chemical and physical data|
|Molar mass||344.879 g/mol g·mol−1|
|3D model (JSmol)|
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.
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 is a progestogen, or an agonist of the progesterone receptor. It is an atypical progestogen similarly to dydrogesterone. For instance, unlike other progestogens, trengestone and dydrogesterone do not increase body temperature (i.e., have no hyperthermic effect). In addition, whereas other progestogens are antigonadotropic and inhibit ovulation, dydrogesterone is neither antigonadotropic nor progonadotropic and does not affect ovulation, and trengestone appears to be progonadotropic and can be used to induce ovulation. Similarly to dydrogesterone and progesterone, trengestone has no androgenic or estrogenic activity.
Trengestone appears to be a prodrug of 20α-dihydrotrengestone (20α-DHTG), as it is largely transformed into this major metabolite upon oral administration. 20α-DHTG has potent progestogenic activity, with peak levels of this metabolite occurring at 2 to 4 hours following administration of trengestone and with a biological half-life of 8 to 14 hours. Trengestone is excreted 41 to 46% in urine and up to 30% unchanged in feces, suggesting that a significant portion of the medication is not absorbed from the gastrointestinal tract. The metabolism and pharmacokinetics of trengestone have been reviewed.
Trengestone, also known as 1,6-didehydro-6-chlororetroprogesterone or as 6-chloro-9β,10α-pregna-1,4,6-triene-3,20-dione, is a synthetic pregnane steroid and a derivative of progesterone and retroprogesterone. Retroprogesterone derivatives like trengestone are analogues of progesterone in which the hydrogen atom at the 9th carbon has been switched from the α-position (below the plane) to the β-position (above the plane) and the methyl group at the 10th carbon has been switched from the β-position to the α-position. This results in a "bent" configuration in which the plane of rings A and B is orientated at a 60° angle below the rings C and D. Analogues of trengestone include dydrogesterone (6-dehydroretroprogesterone) and Ro 6-3129 (16α-ethylthio-6-dehydroretroprogesterone).
Trengestone was marketed under the brand names Reteroid, Retroid, and Retrone.
Trengestone is no longer marketed and hence is no longer available in any country.
Ro 4-8347 (21), a potent orally active progestagen, when given at the dose of 4 mg/day in the second half of the cycle, was found clinically useful in anovulatory women with decreased ovarian function.109
Fig. 17. Lack of hyperthermic effect of retroprogesterone derivative (Trengestone).
Trengestone, contrary to [dydrogesterone], not only does not inhibit ovarian activity while exerting a progestation effect, but it stimulates the former. One tablet per day is administered from the 5th [...] Both dydrogesterone and trengestone can inhibit ovulation in the rat and rabbit, but only the latter compound can do so in women — at doses far above the therapeutic range. Various clinical reports have suggested, on the basis of quite unrelated findings, that trengestone may, despite lack of inherent estrogenicity, somehow cause an indirect stimulation of the production of endogenous estrogens. Numerous investigators (Stamm et al., 1968; Dapunt and Windbichler, 1970) have satisfied themselves that the compound may stimulate ovulation in women with certain endocrinologic imbalances or deficiencies [...]