Estradiol enantate was first described by 1954, and was first studied in combination with DHPA as a combined injectable contraceptive in 1964. The combination was introduced for clinical use by the mid-1970s. Estradiol enantate is not available as a standalone medication (i.e., by itself without DHPA). The combination is available in Latin America and Hong Kong, and was also previously marketed in Spain and Portugal.
Estradiol enantate 10 mg and DHPA 75 mg (brand name Ova Repos; discontinued)
A 6 mg estradiol enantate and 90 mg DHPA formulation was also studied, but was never marketed. The combination of estradiol enantate and DHPA has also been studied at other doses ranging from 5 to 50 mg estradiol enantate and 75 to 200 mg DHPA.
The combination of estradiol enantate and DHPA is provided in ampoules at estradiol enantate concentrations of 5 mg/mL and 10 mg/mL.
20, 25, 50, or 100 mg per pellet (usually every 6 months)
Estradiol Implants, Meno-Implant
Abbreviations: E2 = Estradiol. Footnotes:a = Discontinued or mostly discontinued. Notes: (1): This table mostly does not include combination products, for instance estradiol formulated in combination with a progestogen or androgen. (2): This table does not include compounded estradiol products; only approved pharmaceutical preparations are included. (3): The availability of pharmaceutical estradiol products differs by country (see Estradiol (medication) § Availability). (4): Some of these formulations and doses have been marketed previously but may no longer be available. Sources: See template.
The pharmacokinetics of estradiol enantate have been assessed in a number of studies. It has usually been studied in combination with DHPA. Following an intramuscular injection of estradiol enantate, levels of estradiol have been found to peak after 3 to 8 days. Maximal levels of estradiol after a 5 mg injection of estradiol enantate have been found to be about 163 to 209 pg/mL and after a 10 mg injection of estradiol enantate have been found to be about 283 to 445 pg/mL. However, one outlying study reported peak estradiol levels of 850 pg/mL after an intramuscular injection of 10 mg estradiol enantate in three postmenopausal women. It used radioimmunoassay for the determinations, with no mention of chromatographic separation. Estradiol levels following an intramuscular injection of 10 mg estradiol enantate have been found to return to baseline levels of around 50 pg/mL after about 20 to 30 days. However, a metabolic study found that traces of radiolabeled estradiol enantate remained detectable in blood for at least 30 to 40 days and for as long as 60 days. Studies have reported that the elimination half-life of estradiol enantate after a single 10 mg intramuscular injection was 5.6 to 7.5 days. The volume of distribution of estradiol enantate has been reported to be 5.087 L. Estradiol enantate is excreted preferentially in urine.
There were concerns about possible accumulation of estradiol enantate and consequent estrogenic overexposure with once-monthly combined injectable contraceptives containing the medication due its long duration, and this may have limited the use of such combined injectable contraceptives. Subsequent clinical studies have found that there is very limited or no accumulation of estradiol enantate when it is used in once-a-month injectable contraceptives.
Hormone levels with intramuscular estradiol enantate
E2-EN/DHPA is the most widely used combined injectable contraceptive in Latin America. It was estimated in 1995 that E2-EN/DHPA was used as a combined injectable contraceptive in Latin America by at least 1 million women. However, combined injectable contraceptives like E2-EN/DHPA are unlikely to constitute a large proportion of total contraceptive use in the countries in which they are available.
^ abcdefghijMichael Oettel; Ekkehard Schillinger (6 December 2012). Estrogens and Antiestrogens II: Pharmacology and Clinical Application of Estrogens and Antiestrogen. Springer Science & Business Media. pp. 261, 271. ISBN978-3-642-60107-1. Natural estrogens considered here include: [...] Esters of 17β-estradiol, such as estradiol valerate, estradiol benzoate and estradiol cypionate. Esterification aims at either better absorption after oral administration or a sustained release from the depot after intramuscular administration. During absorption, the esters are cleaved by endogenous esterases and the pharmacologically active 17β-estradiol is released; therefore, the esters are considered as natural estrogens. [...] Wiemeyer et al. (1986) measured elevated estradiol levels up to 31 days after an intramuscular dose of 10mg estradiol enanthate.
^Coutinho EM, Spinola P, Barbosa I, Gatto M, Tomaz G, Morais K, Yazlle ME, de Souza RN, Pinho Neto JS, Leal Wde B, Leal C, Hippolito SB, Abranches AD (March 1997). "Multicenter, double-blind, comparative clinical study on the efficacy and acceptability of a monthly injectable contraceptive combination of 150 mg dihydroxyprogesterone acetophenide and 10 mg estradiol enanthate compared to a monthly injectable contraceptive combination of 90 mg dihydroxyprogesterone acetophenide and 6 mg estradiol enanthate". Contraception. 55 (3): 175–81. doi:10.1016/S0010-7824(97)00018-8. PMID9115007.
^Coutinho EM, Spinola P, Tomaz G, Morais K, Nassar de Souza R, Sabino Pinho Neto J, de Barros Leal W, Bomfim Hippolito S, D'Aurea Abranches A (April 2000). "Efficacy, acceptability, and clinical effects of a low-dose injectable contraceptive combination of dihydroxyprogesterone acetophenide and estradiol enanthate". Contraception. 61 (4): 277–80. doi:10.1016/S0010-7824(00)00099-8. PMID10899484.
^Midwinter, Audrey (1976). "Contraindications to estrogen therapy and management of the menopausal syndrome in these cases". In Campbell, Stuart (ed.). The Management of the Menopause & Post-Menopausal Years: The Proceedings of the International Symposium held in London 24–26 November 1975 Arranged by the Institute of Obstetrics and Gynaecology, The University of London. MTP Press Limited. pp. 377–382. doi:10.1007/978-94-011-6165-7_33. ISBN978-94-011-6167-1.
^ abDe Aguilar MA, Altamirano L, Leon DA, De Fung RC, Grillo AE, Gonzalez JD, Canales JR, Sanchez Jdel C, Pozuelos JL, Ramirez L, Rigionni R, Salgado JS, Torres L, Vallecillos G, Zambrano EJ, Zea C (December 1997). "Current status of injectable hormonal contraception, with special reference to the monthly method". Adv Contracept. 13 (4): 405–17. doi:10.1023/A:1006501526018. PMID9404550.
^Camara, V. L., Zanardi, U. V., Glezer, A., Paraiba, D. B., Bronstein, M. D., Mendonca, B. B., & Costa, E. M. F. (2010, June). Estrogen as a Presumed Risk Factor for Prolactinoma in a Male-to-Female Transsexual Patient. Endocrine Reviews, Supplement 1, 31(3), S347–S347. 10.1210/endo-meetings.2010.PART1.P6.P1-288. [www.endocrine.org]
^Camara, V. L. (2010). Estradiol enantate First report of prolactinoma, in a transsexual. Reactions, 1311, 24. 10.2165/00128415-201013110-00077. [link.springer.com]
^Cheng ZN, Shu Y, Liu ZQ, Wang LS, Ou-Yang DS, Zhou HH (February 2001). "Role of cytochrome P450 in estradiol metabolism in vitro". Acta Pharmacol. Sin. 22 (2): 148–54. PMID11741520.
^ abcdefghRecio R, Garza-Flores J, Schiavon R, Reyes A, Diaz-Sanchez V, Valles V, Luz de la Cruz D, Oropeza G, Perez-Palacios G (June 1986). "Pharmacodynamic assessment of dihydroxyprogesterone acetophenide plus estradiol enanthate as a monthly injectable contraceptive". Contraception. 33 (6): 579–89. doi:10.1016/0010-7824(86)90046-6. PMID3769482.
^ abcdeSchiavon R, Benavides S, Oropeza G, Garza-Flores J, Recio R, Díaz-Sanchez V, Pérez-Palacios G (June 1988). "Serum estrogens and ovulation return in chronic users of a once-a-month injectable contraceptive". Contraception. 37 (6): 591–8. doi:10.1016/0010-7824(88)90005-4. PMID3396358.
^ abcWiemeyer JC, Sagasta CL, Roncales Mateo JM, Lavarello AC, Angel de Toro LA, Salas Diaz R (July 1990). "Multicentred clinical study of the metabolic effect of the monthly injectable contraceptive containing dihydroxyprogesterone acetophenide 150 mg + estradiol enanthate 10 mg". Contraception. 42 (1): 13–28. doi:10.1016/0010-7824(90)90088-D. PMID2117515.
^Oliva Filho, W. M., & Santos, N. da C. (1992). Efeitos na coagulação sanguinea em usuárias da associação acetofenido de dihidroxiprogesterona 150mg e enantato de estradiol 10mg como metodo anticoncepcional injetavel. Universidade de São Paulo, São Paulo. [bdpi.usp.br]
^Tavares, Maria Clotilde H.; Belham, Flávia Schechtman; Duarte, Rosangela Correa Rodrigues (2018). "Risco de doenca tromboliticas apos o uso de algestona acetofenida e enantato de estradiol". Revista de Patologia do Tocantins. 5 (1): 17. doi:10.20873/uft.2446-6492.2018v5n1p17. ISSN2446-6492.
^Moguilevsky JA, Wiemeyer JC, Sagasta CL, Leiderman S (November 1986). "Estrogenic activities of estradiol enantate and ethinylestradiol compared at a clinical level". Arzneimittelforschung. 36 (11): 1671–4. PMID3101711.
^ abPercy Roberts Wilde; Carey Franklin Coombs; Arthur J. Rendle Short (1959). The Medical Annual: A Year Book of Treatment and Practitioner's Index ... Publishing Science Group. As in the case of progestogens the esters of oestradiol vary in the duration of their effect. Oestradiol benzoate is short-acting (three days to a week). Oestradiol valerianate is somewhat longer-acting, and oestradiol enanthate and undecylate have considerably more prolonged duration of effectiveness. The undecylate may remain effective for some months, and should not be employed, [...]
^Gauthier, B; Le Dreff, L; Aubry, R (1958). "Hormone derivatives of long-lasting action. I. Esters of estradiol". Annales Pharmaceutiques Francaises. 16: 757–66. ISSN0003-4509. Treating 10 g. estradiol benzoate in 30 cc.dry C5H5N dropwise with 4.3 g. n-C6H13COCl (b20 71-2°), heating 1 hr. at 50-60°, pouring into 100 cc. 10% H2SO4, sepg. the oil after its solidification, washing with petr. ether, heating with 50 cc. MeOH, and cooling gave 10 g. 17-heptoyl-3β-benzoylestradiol, m. 95-8°. Dissolving 10 g. of this in 210 cc. 0.1N NaOH in MeOH and 40 cc. Me2CO with stirring, adding HCl to pH 7, filtering, evapg. in vacuo, and stirring the residue with petr. ether gave 7.9 g. 17-heptoyl-β-estradiol, m. 94-6° (iso-Pr2O). Adding to 5 g. estradiol stirred in 10 cc. anhyd. pyridine 8 g. n-C10H21COCl (b20 135-6°), keeping 1 hr. at 100°, cooling, adding 50 cc. 10% H2SO4, dissolving the sepd. ester in 50 cc. iso-Pr2O, washing with satd. NaHCO3 soln. and H2O, drying, and evapg. at room temp. gave 10.7 g. 3,17-diundecanoylestradiol, m. 48-9° (MeOH-Me2CO, then Me2O-Et2O), λmax. (0.005% in MeOH contg. 4% iso-Pr2O) 268 mμ, λmin. 282 and 250 mμ, inflexion 215 mμ. Stirring 8.8 g. estradiol divalerate in 90 cc. MeOH and 0.4 g. NaOH under N 210 min. to soln., adding 20% HCl to pH 7, evapg. in vacuo to 10 cc., keeping overnight at a low temp., and washing with H2O, MeOH, and petr. ether gave 4.4 g. 17-valeryl-β-estradiol, m. 145-6°, λmax. (0.005% in EtOH) 282 mμ, λmin. 248 mμ, inflexion 215 mμ. A single dose of 25 mg. of the diundecanate gave a therapeutic effect lasting 3 weeks.
^241206 ES 241206, "Esters of cortical hormones, androgens, or esterogens by transesterification and alcoholysis"
^ abThomas Rabe; Benno Runnebaum (6 December 2012). Fertility Control — Update and Trends: Update and Trends. Springer Science & Business Media. pp. 183–. ISBN978-3-642-86696-8. Two additional monthly, combined injectable methods warrant mention. Deladroxate (commercially labelled as Perlutan, Topasel, Agurin, Horprotal and Uno-Ciclo in various countries), is a combination of 150 mg dihydroxyprogesterone acetophenide and 10 mg estradiol enanthate, and is available in many Latin American countries and Spain. The method is highly effective, without a single pregnancy reported in large clinical trials (Koetsawang 1994). Although available since the 1960s, the method has not been studied as extensively as Cyclofem or Mesigyna. The original manufacturer withdrew support due to toxicological concerns with dihydroxyprogesterone acetophenide, and clinical evaluations continue to be published. A recent dose-finding trial compared the standard available dose of 150/10 with a lower dose of 90/6, and concluded the lower dose was equally effective (Coutinho et al., 1997).