API

Drug classification

Norelgestromin: Progestogen; Ethinyloestradiol: Oestrogen; Combined hormonal contraceptive.

Dosage form

Transdermal Patch

API strength per dosage

6 mg norelgestromin (NGMN) and 600 micrograms of…

Dose

Apply one EVRA patch (containing 6 mg norelgestromin and 0.6 mg ethinylestradiol) weekly for three consecutive weeks, followed by a patch-free week; not recommended for females under 18 years; use with caution in women over 90 kg due to reduced efficacy; contraindicated in severe hepatic impairment.

Mechanism of action

Norelgestromin binds to progesterone receptors and inhibits gonadotropin (LH, FSH) secretion via negative feedback on the hypothalamic-pituitary-gonadal axis; ethinylestradiol binds to estrogen receptors, further suppressing FSH. Together, they inhibit ovulation, thicken cervical mucus, and alter endometrial receptivity, preventing fertilization and implantation.

Indications

Contraception, prevention of pregnancy.

Side effects

Venous thromboembolism, arterial thromboembolism, hypertension, headache, nausea, breast tenderness, mood changes, skin irritation at application site, breakthrough bleeding, increased risk of myocardial infarction, stroke.

Pregnancy category

Precautions

Contraindications