Products
Estradiol is commercially available in tablet, transdermal patch, transdermal gel, vaginal ring, and vaginal tablet forms, among others. It is also combined fixed with progestogens.
Structure and properties
Estradiol (C18H24O2, Mr = Mr = 272.4 g/mol) exists as a white crystalline powder that is practically insoluble in water. Synthetic estradiol is bioidentical with human 17β-estradiol. In pharmaceuticals, it is often present as estradiol hemihydrate (estradiol – 0.5 H2O). The prodrug estradiol valerate is also often used, which has better absorption and is metabolized in the body to estradiol and valeric acid. Estradiol is distinguished from other steroids by the aromatic ring and is also referred to as E2 because of the two hydroxy groups (-diol).
Effects
Estradiol (ATC G03CA03) replaces the natural female sex hormone in the body. It is effective against the complaints that arise as a result of estrogen deficiency and prevents the development of osteoporosis. Its multiple metabolic effects are based on binding to intracellular estrogen receptors. Estradiol is subject to pronounced first-pass metabolism and therefore has a low oral bioavailability of only about five percent! First-pass metabolism is bypassed during transdermal application. Estradiol, produced primarily by the ovaries, is the most important and potent natural estrogen.
Indications
- Hormone replacement therapy (HRT), for the treatment of symptoms of estrogen deficiency.
- Menopausal symptoms, hot flashes.
- Vaginal dryness, atrophic vaginitis
- Osteoporosis prophylaxis (2nd choice).
- Contraception
Dosage
According to the professional information. The tablets are usually taken once a day at the same time of day. In women with an intact uterus, a progestin must also be administered. The transdermal patches need to be applied less frequently, depending on the product, such as only once or twice a week.
Contraindications
- Hypersensitivity
- Breast cancer
- Estrogen-dependent neoplasms, endometrial cancer.
- Not clarified vaginal bleeding
- Severe liver disease
- Thromboembolic diseases
- Coagulation disorders, thrombophlebitis
- Porphyria
- Pregnancy and lactation
Full precautions can be found in the drug label.
Interactions
Estradiol is predominantly biotransformed by CYP3A4 and corresponding drug-drug interactions with CYP inhibitors and inducers are possible.
Adverse effects
The most common potential adverse effects with systemic use include:
- Vaginal bleeding
- Abdominal pain, nausea
- Breast tenderness, breast enlargement, breast pain.
- Depression
- Weight gain
- Headache, dizziness
- Cramps in the legs
- Edema
- Reactions at the application site
Very rarely, serious side effects such as ovarian cancer, liver tumors, and severe cardiovascular disease may occur, especially with long-term therapy.
