Drug Guide
Conjugated Estrogens (Enjuvia)
Classification
Therapeutic: Hormone Replacement Therapy
Pharmacological: Estrogen, Estrogen Derivative
FDA Approved Indications
- Treatment of vasomotor symptoms associated with menopause
- Atrophic vulva and vagina in postmenopausal women
- Prevention of postmenopausal osteoporosis in women with a contraindication to other osteoporosis treatments
Mechanism of Action
Conjugated estrogens bind to estrogen receptors in the nucleus of target tissues, activating estrogen-responsive genes which regulate gene expression and influence the growth and differentiation of estrogen-dependent tissues.
Dosage and Administration
Adult: Typically 0.3 to 1.25 mg daily, taken orally. Dose depends on condition being treated and response.
Pediatric: Not FDA approved for pediatric use.
Geriatric: Use cautiously; start at the lowest effective dose, especially in women over 65.
Renal Impairment: Adjustments not typically required, but monitor closely.
Hepatic Impairment: Use with caution; contraindicated in severe hepatic disease.
Pharmacokinetics
Absorption: Well-absorbed orally, with a bioavailability of approximately 2% due to first-pass metabolism.
Distribution: Widely distributed; peak plasma concentrations occur about 1-2 hours after administration.
Metabolism: Extensively metabolized in the liver via conjugation (glucuronidation and sulfation).
Excretion: Excreted predominantly in urine as conjugates.
Half Life: Approximate plasma half-life is 13-20 hours.
Contraindications
- Undiagnosed abnormal genital bleeding
- History of estrogen-dependent tumors (e.g., breast cancer)
- Active or past history of thromboembolic disorders
- Unique hypersensitivity to conjugated estrogens
Precautions
- History of liver disease
- History of cardiovascular disease
- Use with caution in women with migraine with aura
- Pregnancy category X
Adverse Reactions - Common
- Breast tenderness (Common)
- Nausea (Common)
- Headache (Common)
Adverse Reactions - Serious
- Deep vein thrombosis (Less common)
- Stroke (Less common)
- Endometrial cancer (if used without progesterone in women with intact uterus) (Potentially increased)
Drug-Drug Interactions
- APPERENTLY INCREASES EFFECTS with certain anticoagulants
- Decreases effectiveness of insulin and oral hypoglycemics
Drug-Food Interactions
- Concomitant use with smoking increases risk of thromboembolism
Drug-Herb Interactions
- St. John's Wort may reduce effectiveness
Nursing Implications
Assessment: Monitor for bleeding irregularities, breast changes, weight, and BP.
Diagnoses:
- Risk for thromboembolic disorders
- Altered tissue perfusion
Implementation: Administer with food if GI upset occurs; monitor for side effects and efficacy.
Evaluation: Assess symptom relief and monitor for adverse effects regularly.
Patient/Family Teaching
- Take medication exactly as prescribed, preferably at the same time daily.
- Report signs of blood clots, unusual vaginal bleeding, or breast lumps.
- Use additional contraceptive methods if needed—estrogens do not prevent pregnancy.
- Avoid smoking, especially if over age 35.
- Regularly schedule health screenings, including mammograms and pelvic exams.
Special Considerations
Black Box Warnings:
- Endometrial cancer risk if used without progestin in women with an intact uterus.
- Increased risk of cardiovascular events, especially in older women or with extended use.
Genetic Factors: Limited data; consult with a specialist if genetic predispositions to thromboembolism are known.
Lab Test Interference: Estrogens may alter thyroid function tests and clotting studies.
Overdose Management
Signs/Symptoms: Nausea, vaginal bleeding, nausea, or vomiting.
Treatment: Supportive care; gastric lavage may be considered; no specific antidote.
Storage and Handling
Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F), away from moisture and sunlight.
Stability: Stable under recommended storage conditions for the shelf life indicated.