Description

Estradiol valerate is an estradiol ester or a prodrug of estradiol. As such, it is an estrogen or an agonist of the estrogen receptors. Its structure is similar to that of 17β-estradiol and which is rapidly metabolized to 17β-estradiol and valeric acid.

Estradiol valerate and estradiol

The affinity of estradiol valerate for the estrogen receptor is approximately 50 times lower than that of estradiol. Estradiol valerate is essentially inactive in terms of the estrogenic effect itself, acting solely as a prodrug to estradiol. The molecular weight of estradiol valerate is about 131% of that of estradiol due to the presence of its C17β valerate ester, and hence estradiol valerate contains about 76% of the amount of estradiol of an equal dose of estradiol[1]. Aside from dose adjustment to account for the difference in molecular weight, oral estradiol valerate is considered to be equivalent to oral estradiol. Because estradiol valerate is a prodrug of estradiol, it is considered to be a natural and bioidentical form of estrogen.

Uses

Estradiol valerate is a synthetic steroid estrogen that includes ethinyl estradiol, estradiol valerate, estropipate, conjugate esterified estrogen, and quinestrol. Several synthetic estrogens are available for therapeutic use[2]. Estradiol valerate has been used to create a novel four-phasic oral contraceptive pill effective in both pregnancy prevention and the treatment of heavy menstrual bleeding[3]. It is used in hormone therapy for menopausal symptoms and low estrogen levels, hormone therapy for transgender people, and hormonal birth control. It is also used in the treatment of prostate cancer.

References

[1] Millán M, et al. A worldwide yearly survey of new data in adverse drug reactions and interactions. Side Effects of Drugs Annual, 2014.

[2] Düsterberg B, et al. Pharmacokinetic and pharmacological features of oestradiol valerate. Maturitas, 1982; 4: 315–324.

[3] Stanczyk F, et al. Ethinyl estradiol and 17β-estradiol in combined oral contraceptives: pharmacokinetics, pharmacodynamics and risk assessment. Contraception, 2013; 87: 706–727.