Oestradiol
Synonyms :
Estradiol, Estradiol Acetate, Estradiol Cypionate, Estradiol Valerate
Mechanism :
Ethinyl estradiol is a synthetic derivative of the natural estrogen estradiol. Like estradiol, it promotes growth of the endometrium and thickening, stratification, and cornification of the vagina. It causes growth of the ducts of the mammary glands but inhibits lactation. It also inhibits the anterior pituitary.
Indication :
- Delayed puberty in females
- Fusion of labia
- Tall stature
Contraindications :
Contraindicated in patients with a history or family history of thromboembolism, moderate to severe hyperlipoproteinaemia, severe liver disease and porphyria.
Dosing :
Delayed puberty in females:
12-18 years: 0.5-2 mg PO OD. Start with 0.25 mg PO OD. Increase every 6 months to 0.5, 1 and then 2 mg. Add progestogen after 18-24 months of estrogen therapy for last 10-12 days of menstrual cycle. Maintenance dose of 2 mg combined with progestogen.
Transdermal patch can be applied weekly. Start with 0.025 mg patch per week, increase the dose every 6 months. Add progestogen after 18-24 months of estrogen therapy for last 10-12 days of menstrual cycle. Can cycle for 3 weeks on and 1 week off therapy.
Fusion of labia:
1 month and older: Apply 0.01% cream twice a day for 6 weeks vaginally.
Adverse Effect :
Nausea, vomiting, abdominal cramps, bloating, headache, migraine, dizziness, chorea, spotting, menstrual changes, breakthrough bleeding, like dysmenorrhea, amenorrhea during and after treatment, breast tenderness and enlargement, chloasma or melasma, loss of scalp hair, hirsutism, steepening of corneal curvature, intolerance to contact lenses.
Interaction :
Rifampicin, Phenobarbital, Carbamazepine and Phenytoin: Can lower the level of ethinylestradiol by accelerating its metabolism.
Warfarin: Ethinylestradiol may reduce the effects of anticoagulants
Insulin or Hypoglycemic Drugs: The doses may need to be adjusted due to a mild diabetogenic effect.
Theophylline: Clearance of theophylline may be reduced due to the inhibition of its metabolism.
Hepatic Dose :
Use is contraindicated with hepatic dysfunction or disease.