Estradiol undecylate

Estradiol undecylate (EU or E2U), also known as estradiol undecanoate and formerly sold under the brand names Delestrec and Progynon Depot 100 among others, is an estrogen medication which has been used in the treatment of prostate cancer in men. It has also been used as a part of hormone therapy for transgender women. Although estradiol undecylate has been used in the past, it was discontinued and hence is no longer available. The medication has been given by injection into muscle usually once a month. Side effects of estradiol undecylate in men may include breast tenderness, breast development, feminization, sexual dysfunction, infertility, fluid retention, and cardiovascular issues. Estradiol undecylate is an estrogen and hence is an agonist of the estrogen receptor, the biological target of estrogens like estradiol. It is an estrogen ester and a very long-lasting prodrug of estradiol in the body. Because of this, it is considered to be a natural and bioidentical form of estrogen. An injection of estradiol undecylate has a duration of about 1 to 4 months. Estradiol undecylate was first described in 1953 and was introduced for medical use by 1956. It remained in use as late as the 2000s before being discontinued. Estradiol undecylate was marketed in Europe, but does not seem to have ever been available in the United States. It was used for many years as a parenteral estrogen to treat prostate cancer in men, although it was not employed as often as polyestradiol phosphate. Estradiol (medication)#Medical uses Estradiol undecylate has been used as a form of high-dose estrogen therapy to treat prostate cancer, but has since largely been superseded for this indication by newer agents with fewer adverse effects (e.g., gynecomastia and cardiovascular complications) like () analogues and nonsteroidal antiandrogens. It has been assessed for this purpose in a number of clinical studies. It has been used at a dosage of 100 mg every 3 to 4 weeks (or once a month) by intramuscular injection for this indication.