Overview
Ethinylestradiol/Levonorgestrel is a combined oral contraceptive containing synthetic estrogen (ethinylestradiol) and progestin (levonorgestrel). It prevents pregnancy primarily by inhibiting ovulation, thickening cervical mucus to impede sperm penetration, and altering the endometrium to prevent implantation. Microgynon is a widely used brand in Jordan with multiple formulations.
Mechanism of Action
Ethinylestradiol suppresses follicle-stimulating hormone (FSH) and luteinizing hormone (LH) via negative feedback on the hypothalamus and pituitary, inhibiting follicular development and ovulation. Levonorgestrel enhances contraceptive effects by further suppressing LH surge, thickening cervical mucus (reducing sperm motility), and altering endometrial lining to prevent implantation.
Indications
- Prevention of pregnancy
- Regulation of menstrual cycles
- Treatment of dysmenorrhea
- Management of acne (in some formulations)
- Reduction of ovarian cyst risk
Dosage
One tablet daily for 21 days followed by a 7-day pill-free interval (21/7 regimen) or 28-day continuous regimen with placebo pills. For Microgynon ED: one active tablet daily for 21 days, then one inactive tablet daily for 7 days. Start on first day of menstrual cycle or as directed by healthcare provider.
Contraindications
- Thromboembolic disorders (DVT, PE)
- Cerebrovascular or coronary artery disease
- Severe hypertension
- Diabetes with vascular complications
- Known or suspected estrogen-dependent neoplasia
- Undiagnosed abnormal genital bleeding
- Pregnancy
- Severe liver disease
- Hypersensitivity to components
Side Effects
- Nausea
- Headache
- Breast tenderness
- Weight changes
- Mood changes
- Breakthrough bleeding
- Amenorrhea
- Decreased libido
- Chloasma
- Contact lens intolerance
- Hypertension
- Gallbladder disease
- Thromboembolic events (rare)
Interactions
- Enzyme inducers (rifampicin, carbamazepine, phenytoin, St. John's wort) reduce efficacy
- Antibiotics (ampicillin, tetracycline) may decrease contraceptive effect
- HIV protease inhibitors alter metabolism
- Warfarin (altered anticoagulant effect)
- Cyclosporine (increased levels)
- Lamotrigine (reduced levels)
- Selegiline (increased side effects)