Ethinylestradiol

What it is and how it works

Ethinylestradiol is a potent orally active synthetic oestrogen whose 17α-ethinyl group slows hepatic metabolism. It binds oestrogen receptors and reproduces the effects of endogenous oestrogens, including development of secondary sexual characteristics, suppression of gonadotrophin secretion and, in men, suppression of testosterone.

Indications

Single-ingredient tablets are used for female hypogonadism and oestrogen replacement, and for palliative treatment of hormone-sensitive prostate cancer; it is also the oestrogen component of most combined oral contraceptives.

Dosage and administration (summary)

Oral; dose depends on the indication, ranging from microgram doses daily (often cyclically) for oestrogen replacement to higher doses for palliative treatment of prostate cancer, as specified in the product information.

Contraindications

Oestrogen-dependent tumours (except in palliative treatment of prostate cancer), undiagnosed genital bleeding, current or previous venous or arterial thromboembolism, thrombophilia, active liver disease, and porphyria.

Warnings and precautions

Risk of venous and arterial thromboembolism is dose-related and increased by smoking, obesity and immobility; women with an intact uterus require a progestogen to prevent endometrial hyperplasia. Fluid retention, hypertension, cholestasis and gallbladder disease may occur, and gynaecomastia and cardiovascular events are notable in men treated for prostate cancer.

Pregnancy

Contraindicated in pregnancy.

Storage and supply

Store below 25 °C, protected from light and moisture.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.