Overview
Estradiol is a form of estrogen, a major female sex hormone. It is commonly used in hormone replacement therapy (HRT) to relieve menopausal symptoms.

Mechanism of Action
It binds to intracellular estrogen receptors, regulating gene transcription to maintain the female reproductive system and secondary sexual characteristics. It helps alleviate estrogen deficiency symptoms.

Dosage and Administration
Dosage varies widely depending on the indication and route of administration (oral, transdermal patch, topical gel). The lowest effective dose should be used for the shortest duration necessary.

Side Effects
Common side effects include breast tenderness, nausea, headache, weight changes, and mood swings. Long-term use may increase the risk of endometrial cancer (if used without a progestin in women with an intact uterus), breast cancer, and cardiovascular events.

Contraindications
Contraindicated in patients with undiagnosed abnormal genital bleeding, known or suspected breast cancer, estrogen-dependent tumors, active liver disease, or a history of thromboembolic disorders.