Estradiol acetate (EA), sold under the brand names Femtrace, Femring, and Menoring, is an estrogen medication which is used in hormone therapy for the treatment of menopausal symptoms in women. It is taken by mouth once daily or given as a vaginal ring once every three months. Side effects of estradiol acetate include breast tenderness, breast enlargement, nausea, headache, and fluid retention. Estradiol acetate 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 prodrug of estradiol in the body. Because of this, it is considered to be a natural and bioidentical form of estrogen. Estradiol acetate was introduced for medical use in 2001. It is available in the United States and the United Kingdom. The formulation for use by mouth has been discontinued in the United States. Medical uses Estradiol acetate is used as a component of menopausal hormone therapy to treat and prevent menopausal symptoms such as hot flashes and osteoporosis in women. The Women's Health Initiative studies report increased health risks for menopausal women when using unopposed estrogens. Estrogens with or without progestins should be prescribed at the lowest effective doses and for the shortest duration consistent with treatment goals and risks for the individual woman. Available forms Estradiol acetate comes in the form of 0.45, 0.9, and 1.8 mg oral tablets (Femtrace) and in the form of 12.4 or 24.8 mg vaginal rings that release 50 or 100 μg/day estradiol for 3 months (Femring, Menoring). However, the Femtrace product was discontinued in the United States. Contraindications Contraindications of estrogens include coagulation problems, cardiovascular diseases, liver disease, and certain hormone-sensitive cancers such as breast cancer and endometrial cancer, among others. Side effects The side effects of estradiol acetate are the same as those of estradiol. Examples of such side effects include breast tenderness and enlargement, nausea, bloating, edema, headache, and melasma. Overdose Symptoms of estrogen overdosage may include nausea, vomiting, bloating, increased weight, water retention, breast tenderness, vaginal discharge, heavy legs, and leg cramps. These side effects can be diminished by reducing the estrogen dosage. Interactions Inhibitors and inducers of cytochrome P450 may influence the metabolism of estradiol and by extension circulating estradiol levels. Pharmacology Pharmacodynamics Estradiol acetate is an estradiol ester, or a prodrug of estradiol. As such, it is an estrogen, or an agonist of the estrogen receptors. Estradiol