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GENITO URINARY SYSTEM AND SEX HORMONES › SEX HORMONES AND MODULATORS OF THE GENITAL SYSTEM › ESTROGENS › Natural and semisynthetic estrogens, plain
estradiol
G03CA03
Forms & Strengths
- Oral tablets: 0.5 mg, 1 mg, 2 mg
- Transdermal patch: 0.025, 0.0375, 0.05, 0.075, 0.1 mg/24 hours
- Topical gel/emulsion: 0.25 mg, 0.5 mg, 0.75 mg, 1 mg per actuation
- Vaginal insert: 4 mcg, 10 mcg
- Vaginal cream: 0.1 mg/g
- Intramuscular injection (valerate/cypionate): 2 mg/mL, 5 mg/mL, 10 mg/mL, 20 mg/mL, 40 mg/mL
Adult Dosing
- Vasomotor symptoms (Oral): 1 mg daily, adjusted based on response; 21 days on, 7 days off or continuous
- Vasomotor symptoms (Transdermal): 0.025 to 0.1 mg patch applied twice weekly or weekly
- Hypoestrogenism (Primary Ovarian Insufficiency): 1 to 2 mg daily orally or equivalent transdermal dose
- Atrophic vaginitis (Vaginal): 10 mcg insert twice weekly, or 2 to 4 g cream daily for 1-2 weeks then tapered
- Prostate cancer (Palliative): 1 to 2 mg orally three times daily
Pediatric Dosing
- Delayed puberty in hypogonadism: Oral 0.1 to 0.5 mg daily or transdermal equivalent, slowly titrated over 1-2 years to adult replacement doses
- Turner syndrome: Initiate low-dose transdermal or oral estradiol around 11-12 years of age, gradually increasing to adult replacement
Indications
- Moderate to severe vasomotor symptoms due to menopause
- Hypoestrogenism due to hypogonadism, castration, or primary ovarian failure
- Atrophic vaginitis and kraurosis vulvae
- Prevention of postmenopausal osteoporosis
- Palliative treatment of advanced androgen-dependent carcinoma of the prostate
Mechanism of Action
- Binds to nuclear estrogen receptors (ER-alpha and ER-beta) in responsive tissues
- Modulates pituitary secretion of gonadotropins (LH and FSH) via negative feedback
- Increases hepatic synthesis of sex hormone-binding globulin, thyroid-binding globulin, and clotting factors while decreasing LDL and increasing HDL cholesterol
Contraindications
- Undiagnosed abnormal genital bleeding
- Known, suspected, or history of breast cancer
- Known or suspected estrogen-dependent neoplasia
- Active deep vein thrombosis, pulmonary embolism, or history of these conditions
- Active or recent arterial thromboembolic disease (stroke, myocardial infarction)
- Liver dysfunction or active liver disease
- Known protein C, protein S, or antithrombin deficiency, or other thrombophilic disorders
- Known hypersensitivity to estradiol
Adverse Reactions
- Cardiovascular: Deep vein thrombosis, pulmonary embolism, stroke, myocardial infarction, hypertension
- Oncologic: Endometrial cancer (if used without a progestin in women with an intact uterus), breast cancer
- Gastrointestinal: Nausea, abdominal cramps, bloating, gallbladder disease, cholestatic jaundice
- Neurologic: Headache, migraine exacerbation, dizziness
- Metabolic: Fluid retention, weight changes, hypercalcemia, changes in lipid profile
- Local/Other: Breast tenderness, breakthrough bleeding, spotting, changes in libido, application site reactions
Drug Interactions
- CYP3A4 inducers (e.g., rifampin, carbamazepine, St. John's wort) decrease estradiol plasma concentrations and efficacy
- CYP3A4 inhibitors (e.g., erythromycin, ketoconazole, grapefruit juice) may increase estradiol exposure
- Coadministration with corticosteroids may lead to corticosteroid toxicity via reduced clearance
- Reduced efficacy of anticoagulants, antidiabetic agents, and antihypertensives
- Hormonal contraceptives and sex hormones may alter thyroid hormone-binding globulin levels
Curated Content: Needs Vetting Before Put to Clinical Use