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Ethinyl Estradiol

Meaning

Ethinyl estradiol is a synthetic, pharmacologically modified derivative of the naturally occurring estrogen, estradiol, characterized by an ethinyl group at the 17-alpha position on the steroid ring. This specific chemical modification confers a dramatically increased resistance to first-pass hepatic metabolism, resulting in significantly enhanced oral bioavailability and a prolonged biological half-life compared to native estradiol. It serves as a core active component in most combined oral contraceptive formulations and is also utilized in specific hormone replacement therapy regimens. Due to its high potency and distinct metabolic profile, its clinical use requires careful consideration of its effects on coagulation and cardiovascular risk markers.