Estradiol is a female sex hormone produced by the ovaries, adrenal gland and also the placenta during pregnancy.
Estradiol is the most important hormone during a female’s reproductive years and is required for reproductive and sexual function as well as having an impact on the health of other organs and tissues.
There are several conditions that are caused by deficient estradiol levels, although levels can be restored with the use of exogenous estradiol. Estrogen preparations may also be used for numerous other conditions.
Some examples of medications that include estradiol are described below:
Contraceptive pill
Estradiol is one of the components of the oral contraceptive pill or birth control pill
Transdermal patch
These skin patches contain estradiol and adhere to the skin so that the hormone can be absorbed into the bloodstream.
Topical estradiol creams, ointments
Vaginal creams containing estradiol are available to ease vaginal dryness and other symptoms associated with the menopause.
Injectable estradiol
Estradiol can also be administered via parenteral or intramuscular injections
Douches and pessaries
Estradiol can also be given in the form of vaginal preparations including douches and pessaries that dissolve within the vagina.
The estradiol found in these preparations is actually an estradiol molecule linked to an alkyl group at the C17 or C3 position, which aids absorption and administration. This forms estradiol acetate, a form of estradiol used in pills or vaginal applications. Another chemical form is estradiol cyprionate, which often makes up the injectable form of the drug.
Estradiol in the pill form is not readily absorbed and may be immediately taken up by the liver, a process called first pass metabolism. This can lead to side effects. The subcutaneous and vaginal routes are not subject to a first pass through the liver.
Further Reading
Anastrozole efficacy in breast cancer prevention for high-risk women linked to estrogen levels