conjugated estrogens

G03CA57

Forms & Strengths

Adult Dosing

Vasomotor symptoms (moderate to severe): 0.625 mg orally daily, cyclic or continuous
Vulvovaginal atrophy: 0.3 mg to 0.625 mg orally daily or 0.5 g to 2 g vaginal cream daily
Hypoestrogenism (due to hypogonadism, castration, or primary ovarian failure): 0.3 mg to 0.625 mg orally daily, cyclically
Postmenopausal osteoporosis prevention: 0.625 mg orally daily, cyclic or continuous
Abnormal uterine bleeding (IV): 25 mg IV, may repeat in 6-12 hours

Pediatric Dosing

Delayed puberty / Hypogonadism: 0.3 mg orally daily, titrated upwards as needed over 6 to 12 months in adolescent females

Indications

Treatment of moderate to severe vasomotor symptoms associated with menopause
Treatment of moderate to severe symptoms of vulvar and vaginal atrophy due to menopause
Treatment of hypoestrogenism due to hypogonadism, castration, or primary ovarian failure
Prevention of postmenopausal osteoporosis
Treatment of acute dysfunctional uterine bleeding due to hormonal imbalance (IV formulation)

Mechanism of Action

Binds to nuclear estrogen receptors (ER-alpha and ER-beta) in responsive tissues
Increases hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin, and other blood clotting factors
Reduces elevated levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in postmenopausal women

Contraindications

Undiagnosed abnormal genital bleeding
Known, suspected, or history of breast cancer
Known or suspected estrogen-dependent neoplasia
Active or history of deep vein thrombosis (DVT) or pulmonary embolism (PE)
Active or history of arterial thromboembolic disease (stroke, myocardial infarction)
Liver dysfunction or disease
Known protein C, protein S, or antithrombin deficiency, or other thrombophilic disorders
Known hypersensitivity to conjugated estrogens

Adverse Reactions

Cardiovascular: Venous thromboembolism, myocardial infarction, stroke
Oncologic: Breast cancer, endometrial cancer (when used unopposed in women with an intact uterus)
Neurologic: Headache, dizziness, migraine
Gastrointestinal: Nausea, abdominal pain, bloating, cholestatic jaundice
Genitourinary: Breakthrough bleeding, spotting, changes in menstrual flow, dysmenorrhea, vaginal candidiasis
Metabolic: Fluid retention, edema, changes in lipid profile

Drug Interactions

CYP3A4 inducers (e.g., rifampin, carbamazepine, phenobarbital): may decrease estrogen concentrations and therapeutic efficacy
CYP3A4 inhibitors (e.g., erythromycin, ketoconazole, grapefruit juice): may increase estrogen plasma concentrations and risk of adverse effects
Corticosteroids: estrogens may increase corticosteroid-binding globulin and reduce clearance, increasing risk of toxicity
Anticoagulants: estrogens may diminish the anticoagulant effect of oral anticoagulants
Antidiabetic agents: estrogen therapy may impair glucose tolerance, requiring adjustment of antidiabetic medication dosage

Curated Content: Needs Vetting Before Put to Clinical Use