Estradiol/megestrol acetate explained

Estradiol/megestrol acetate (E2/MGA), sold under the brand names Mego-E and Chinese injectable No. 2, is a form of combined injectable birth control which is used in the People's Republic of China.[1] [2] [3] [4] [5] [6] [7] It contains 3.5 mg estradiol (E2), an estrogen, and 25 mg megestrol acetate (MGA), a progestin. It is a microcrystalline aqueous suspension with a defined particle size range. The medication is given once per month by injection into muscle.

Studies of E2/MGA have been published.[8] [9] [10] [11] [12] [13] [14] [15] [16] [17] The elimination half-life of MGA in this formulation is 14.35 ± 9.1 days. The plasma protein binding of MGA to albumin is 82.4%, while none is bound to sex hormone-binding globulin. Following an injection of E2/MGA, estradiol increased after 24 hours and persisted at high levels for 5 days, thereafter decreasing to low levels.

In 1969, MGA was studied in China as an aqueous suspension for parenteral administration in animals.[18] The next year, it was studied in women as a progestogen-only injectable contraceptive, with a dosing interval of once every 3 months by intramuscular injection. It was effective as a contraceptive but was associated with menstrual irregularities. Starting in 1973, a combination of estradiol cypionate (EC) and MGA was studied in women as a combined injectable contraceptive over a period of 3 years.[6] [19] E2/MGA, an "improvement" of EC/MGA, was studied in China in large clinical trials from 1977 to 1979 and was approved for use in this country in 1980. By 1987, production of E2/MGA had reached 9 million units per year and had spread to over 22 Chinese provinces and cities. E2/MGA appears to have been discontinued sometime between 2005 and 2008.[20]

A follow-up product consisting of 5 mg estradiol valerate (EV) and 15 mg MGA encapsulated in 50 to 80 μm-diameter microspheres as an aqueous suspension for use by intramuscular injection was developed and studied in China as well but was never marketed.[21] [22] [23] [24] [25] [26] Following an injection, levels of MGA were higher than 2 ng/mL after a day, reached a peak of 3.2 ng/mL after 8 days, remained at levels of 2 ng/mL after 27 days, remained at 1 to 2 ng/mL after 27 to 45 days, and were below 1 ng/mL after 45 to 51 days (0.71 ng/mL on the 51st day).

See also

Notes and References

  1. De-Wei Z . Research activities in the field of oral contraceptives in the People's Republic of China . Acta Obstet Gynecol Scand . Suppl . 105 . 51–60 . 1982 . 6952745 . 10.3109/00016348209155319 . 44858028 .
  2. Newton JR, D'arcangues C, Hall PE . A review of "once-a-month" combined injectable contraceptives . J Obstet Gynaecol (Lahore) . 4 . Suppl 1 . S1–34 . 1994 . 12290848 . 10.3109/01443619409027641 .
  3. Garza-Flores J . Pharmacokinetics of once-a-month injectable contraceptives . Contraception . 49 . 4 . 347–59 . April 1994 . 8013219 . 10.1016/0010-7824(94)90032-9 .
  4. Sang GW . Pharmacodynamic effects of once-a-month combined injectable contraceptives . Contraception . 49 . 4 . 361–85 . April 1994 . 8013220 . 10.1016/0010-7824(94)90033-7 .
  5. Bagade O, Pawar V, Patel R, Patel B, Awasarkar V, Diwate S . Increasing use of long-acting reversible contraception: safe, reliable, and cost-effective birth control . World J Pharm Pharm Sci . 3 . 10 . 364–392 . 2014 . 2278-4357 .
  6. Toppozada MK . Existing once-a-month combined injectable contraceptives . Contraception . 49 . 4 . 293–301 . April 1994 . 8013216 . 10.1016/0010-7824(94)90029-9 .
  7. Book: IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. International Agency for Research on Cancer. Hormonal Contraception and Post-menopausal Hormonal Therapy. 1 January 1999. IARC. 978-92-832-1272-0. 65. 16 September 2018. 28 August 2021. https://web.archive.org/web/20210828080855/https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono72.pdf. dead.
  8. Yian JH, Min HD, Hu YT, Pan JX . "美尔伊"避孕针的临床观察及实验研究 . Mego-E injectable contraceptive: Analysis of clinical observations and laboratory findings . 1983 . Reproduction & Contraception . 3 . 4 . 16–20 . 0253-357X .
  9. Ding J, Guo Q, Pan J, Yan Y . 避孕针剂"美尔伊"作用原理的探讨 . Study on the Mechanism of Injectable Contraceptive Mego-E. . Universitatis Medicinalis Secondae Shanghai . 1985 . 5 . 320–323+385 . 0258-5898 .
  10. Chu YH, Li Q, Zhao ZF . 育龄妇女肌注复方甲地孕酮避孕针的药代动力学 . Pharmacokinetics of megestrol acetate in women receiving IM injection of estradiol-megestrol long-acting injectable contraceptive . April 1986 . The Chinese Journal of Clinical Pharmacology . 4 . 224–229 . 10.13699/j.cnki.1001-6821.1986.04.004 . 1001-6821 .
  11. Zheng H, Tan Y, Bao Y, Ding Y, Wang L, Jiang X, Zhu L, Zhang Z . 复方甲地孕酮注射液的遗传学效应研究. . A study on the genetic effects of "compound megestrol injection" . Genetics and Diseases . 1986 . 3 . 149–153 . 1003-9406 .
  12. Pan J . 复方甲地孕酮避孕针临床研究进展. . Progress in clinical research of compound megestrol acetate injectable needle. . Journal of Shanghai Second Medical University . 1987 . S1 . 71–73 . 0258-5898 .
  13. Yan Y, Pan J, Zhang Y, Kang J . The effect of monthly injectable contraceptive megestrol acetate compound on pituitary-ovarian function. . Journal of Shanghai Second Medical University . 1987 . 2 . 7–12 . 1001-6686 .
  14. Pan J, Yan Y, Li X, Zhang Y, Li M . 潘家骧,严隽鸿,黎小燕,张亚琴,李明光. . Effects of injection Mego-E on blood glucose and serum insulin levels. . Journal of Shanghai Second Medical University . 1987 . 2 . 48–55 . 1001-6686 .
  15. Zhang L, Qi Y, Zhang H . 血浆甲地孕酮的高效液相色谱测定法. . HLPC determination of megestrol in blood plasma. / Determination of plasma megestrol by high performance liquid chromatography. . Pharmaceutical Industry . 1987 . 7 . 311–313 . 10.16522/j.cnki.cjph.1987.07.006 .
  16. Zhou M, Zhang L, Qi Y . 醋酸甲地孕酮与血浆蛋白的结合. . Studies on plasma protein binding of megestrol acetate. . Journal of Shanghai Medical University . 1988 . 1 . 13–17 . 0257-8131 .
  17. Cheng XF, Shao HZ, Chen ZP . 复方甲地孕酮避孕针对人凝血、抗凝血、纤溶及血小板聚集性的影响 . Effect of megestrol acetate compound (injectable contraceptive) on human blood coagulation, anticoagulation activity, fibrinolysis and platelet aggregation . zh . Shengzhi Yu Biyun . 8 . 1 . 22–6 . 1988 . 0253-357X . 12315407 .
  18. Cheng X, Shao H, Yang J, Zhi L, Wang H, Wang Z, etal . September 1977 . 复方甲地孕酮避孕针的药理研究 . Pharmacological studies on the contraceptive injection of megestrol acetate. . Acta Zoologica Sinica . 23 . 3 . 231–237 . 0001-7302 .
  19. Book: Mokhtar K. Toppozada . Monthly Injectable Contraceptives . 93–103 . Goldsmith A, Toppozada M . Long-Acting Contraception . 1983 . 35018604 .
  20. Gallo MF, Grimes DA, Lopez LM, Schulz KF, d'Arcangues C . Combination injectable contraceptives for contraception . The Cochrane Database of Systematic Reviews . 3 . CD004568 . 2013 . 23641480 .
  21. Han Z, Xiao R . 复方甲地孕酮微囊注射液四种配伍量的临床选择. . Clinical evaluation of intramuscular injection of microencapsulated compound megestrol acetate. . Journal of Sichuan Medical College . 1982 . 1 . 93–99 . 1672-173X .
  22. Han ZY, Xiao RQ . Clinical evaluation of intramuscular injection of microencapsulated compound megestrol acetate . Int J Gynaecol Obstet . 22 . 4 . 319–24 . August 1984 . 6152804 . 10.1016/0020-7292(84)90091-2 . 72806071 .
  23. Han ZY, Xiao RQ . A follow-up study of the efficacy and safety of injectable microencapsulated megestrol acetate and a discussion on its contraceptive mechanism . Int J Gynaecol Obstet . 23 . 3 . 207–11 . June 1985 . 2865183 . 10.1016/0020-7292(85)90106-7 . 74276439 .
  24. Lu B, Li TL, Guan Q, Yang HL . 微囊化与未微囊化复方甲地孕酮注射液动物肌内残留率的对比研究 . Comparative study of the residual rates of microencapsulated and unmicroencapsulated compound megestrol acetate injection in animal muscle . zh . Sichuan Yi Xue Yuan Xue Bao . 16 . 1 . 44–8 . March 1985 . 1672-173X . 4012589 .
  25. Lu B, Meng JX, Xie ZY, Pu JX . 复方甲地孕酮微囊注射液溶出度的研究 . Study on dissolution rate of injection of microencapsulated compound megestrol acetate . zh . Hua Xi Yi Ke da Xue Xue Bao . 20 . 1 . 81–84 . March 1989 . 2793150 .
  26. Xu LZ, Han ZY, Yue YC, Yang SZ . 复方甲地孕酮微囊注射液肌注后血药浓度及对垂体-卵巢功能影响的探讨 . Blood levels of megestrol acetate following injection of the microencapsulated compound megestrol acetate and its effect on pituitary-ovarian function . zh . Hua Xi Yi Ke da Xue Xue Bao . 19 . 1 . 97–101 . March 1988 . 1672-173X . 3391610 .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Estradiol/megestrol acetate".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.