Esterified estrogens (EEs), sold under the brand names Estratab and Menest among others, is an

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

medication which is used hormone therapy for

menopausal symptom Menopause, also known as the climacteric, is the time in women's lives when menstrual periods stop permanently, and they are no longer able to bear children. Menopause usually occurs between the age of 47 and 54. Medical professionals often ...

s and low sex hormone levels in women, to treat

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a r ...

in both women and men, and to treat prostate cancer in men. It is formulated alone or in combination with

methyltestosterone Methyltestosterone, sold under the brand names Android, Metandren, and Testred among others, is an androgen and anabolic steroid (AAS) medication which is used in the treatment of low testosterone levels in men, delayed puberty in boys, at low ...

. It is taken

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

Side effect In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...

s of EEs include

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

, breast tension, edema, and

breakthrough bleeding Intermenstrual bleeding, previously known as metrorrhagia, is uterine bleeding at irregular intervals, particularly between the expected menstrual periods. It is a cause of vaginal bleeding. In some women, menstrual spotting between periods occ ...

among others. It is an

, or an agonist of the

estrogen receptor Estrogen receptors (ERs) are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen (17β-estradiol). Two classes of ER exist: nuclear estrogen receptors ( ERα and ERβ), which are members of the ...

s, the

biological target A biological target is anything within a living organism to which some other entity (like an endogenous ligand or a drug) is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets ...

of estrogens like

estradiol Estradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Estradiol is responsible for the development o ...

. EEs are a prodrug mainly of

and to a lesser extent of

equilin Equilin is a naturally occurring estrogen sex hormone found in horses as well as a medication. It is one of the estrogens present in the estrogen mixtures known as conjugated estrogens (CEEs; brand name Premarin) and esterified estrogens (EE ...

. EEs were introduced for medical use by 1970. They are available in only a few countries, such as

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. They have also been marketed in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

and Switzerland in the past.

Medical uses

EEs are used in hormone therapy for

s, female

hypogonadism Hypogonadism means diminished functional activity of the gonads—the testes or the ovaries—that may result in diminished production of sex hormones. Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estroge ...

ovariectomy Oophorectomy (; from Greek , , 'egg-bearing' and , , 'a cutting out of'), historically also called ''ovariotomy'' is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term is mostly used in reference t ...

, and primary ovarian failure and in the treatment of

and prostate cancer.

Available forms

EEs are available in the form of 0.3 mg, 0.625 mg, 1.25 mg, and 2.5 mg

oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or or ...

tablets. Estratest is a combination formulation of 1.25 mg EEs with 2.5 mg

Side effects

Pharmacology

EEs consist primarily of

sodium estrone sulfate Estrone sulfate (E1S) is an estrogen medication and naturally occurring steroid hormone. It is used in menopausal hormone therapy among other indications. As the sodium salt (sodium estrone sulfate), it is the major estrogen component of conj ...

and sodium equilin sulfate, and are very similar to

conjugated estrogens Conjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is used in menopausal hormone therapy and for various other indications. It is a mixture of the ...

(CEEs, conjugated

equine Equinae is a subfamily of the family Equidae, which have lived worldwide (except Indonesia and Australia) from the Hemingfordian stage of the Early Miocene (16 million years ago) onwards. They are thought to be a monophyletic grouping.B. J. Ma ...

estrogens; brand name Premarin). However, EEs and CEEs differ in the sources of their contents and in the percentages of their constituents; CEEs consist of approximately 53% sodium estrone sulfate and 25% sodium

sulfate, while EEs contain about 75 to 85% sodium estrone sulfate and 6 to 11% sodium equilin sulfate. EEs have been found to produce similar serum levels of

estrone Estrone (E1), also spelled oestrone, is a steroid, a weak estrogen, and a minor female sex hormone. It is one of three major endogenous estrogens, the others being estradiol and estriol. Estrone, as well as the other estrogens, are synthesized ...

and

relative to CEEs, although with higher levels of estrone and lower levels of equilin. One study found that the risk of

venous thrombosis Venous thrombosis is blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off (embolizes) and flows to the lungs to ...

may be less with EEs relative to CEEs.

Chemistry

EEs contain synthetic,

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

-derived estrogens and are manufactured from

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu a ...

s and yams.

History

EEs were introduced for medical use by 1970.

Society and culture

Generic names

''Estrogens, esterified'' is the generic name of the drug and its . It is also known as ''esterified estrogens''.

Brand names

EEs are marketed under a variety of brand names including Amnestrogen, Estragyn, Estratab, Evex, Femibel, Femogen, Menest, Neo Estrone Tab, and Oestro-Feminal alone, and, in combination with

, under the brand names Covaryx, Delitan, Eemt, Essian, Estratest, Feminova-T, Menogen, and Syntest.

Availability

EEs are or have been marketed in

, Switzerland, and the

. Both EEs and the combination of EEs and

are listed as being marketed only in Chile and the United States as of present.

References

{{Estrogen receptor modulators Antigonadotropins Combination drugs Estranes Estrogens Hormonal antineoplastic drugs Ketones Organic sodium salts Prodrugs Sulfate esters