ESTROGENS, ESTERIFIED

ESTROGENS, ESTERIFIED (ess'tro-jenz) Estratab, Menest, Menrium, Neo-Estrone  Classifications: hormone; estrogen; Therapeutic: estrogen; female hormone replacement therapy (hrt) Prototype: Estradiol Pregnancy Category: X

Availability

0.3 mg, 0.625 mg, 1.25 mg, 2.5 mg tablets

Action

At the cellular level, estrogens increase cervical secretions, result in proliferation of the endometrium, and increase uterine tone. Estrogens also can affect bone calcium deposition and accelerate epiphyseal closure. Estrogens appear to prevent osteoporosis associated with the onset of menopause; they generally do not reverse bone density loss that has already developed.

Therapeutic Effect

Binds to intracellular receptors that stimulate DNA and RNA to synthesize proteins responsible for effects of estrogen.

Uses

Atrophic vaginitis, kraurosis vulvae and abnormal bleeding (hormonal imbalance), female hypogonadism, castration, primary ovarian failure, vasomotor symptoms associated with menopause, palliative therapy of breast and prostatic carcinomas; prevention of osteoporosis.

Contraindications

Breast cancer; cervical cancer; endometrial cancer; endometrial hyperplasia; prostate cancer; hepatic disease or cancer; hypercalcemia; lupus (SLE); history of thromboembolic disease; known or suspected pregnancy (category X); lactation.

Cautious Use

Hypertension; gallbladder disease; diabetes mellitus; heart failure; kidney dysfunction; migraine headaches; seizure disorders.

Route & Dosage

Menopause Adult: PO 0.3–1.25 mg/d for 21 d each month, adjust to lowest level that gives symptom control (≤0.625 mg/d) Female Hypogonadism, Primary Ovarian Failure, Female Castration Adult: PO 2.5–7.5 mg/d in 1–3 divided doses for 20 d followed by a 10-d rest period, during last 5 d of estrogen, give a PO progestin Breast Cancer Adult: PO 10 mg t.i.d. for 2–3 mo Prostatic Cancer (palliation) Adult: PO 1.25–2.5 mg t.i.d. for several weeks Prevention of Osteoporosis Adult: PO 0.3 mg q.d.

Administration

Oral

• Give with food or fluid of patient's choice.
• Give cyclically, except when used for palliation of cancer.
• Store tablets at 15°–30° C (59°–86° F) in a tightly closed container.

Adverse Effects (≥1%)

CNS: Headache, dizziness, depression, libido changes. CV: Thromboembolic disorders, hypertension. GI: Nausea, vomiting, diarrhea, bloating, cholestatic jaundice. Urogenital: Mastodynia, spotting, changes in menstrual flow, dysmenorrhea, amenorrhea. Metabolic: Reduced carbohydrate tolerance, fluid retention. Other: Leg cramps, intolerance to contact lenses.

Interactions

Drug: barbiturates, phenytoin, rifampin decrease estrogen effect by increasing its metabolism; oral anticoagulants may decrease hypoprothrombinemic effects; interfere with effects of bromocriptine; may increase levels and toxicity of cyclosporine, tcas, theophylline; decrease effectiveness of clofibrate.

Pharmacokinetics

Absorption: Well absorbed with first pass metabolism. Metabolism: Metabolized in GI mucosa and liver to estrone, further metabolized to inactive metabolites. Elimination: In urine and bile. Half-Life: 4–18.5 h.

Nursing Implications

Assessment & Drug Effects

• See nursing implications under estradiol.
• Monitor for and report breakthrough vaginal bleeding.
• Assess for relief of menopausal symptoms.
• Lab tests: Monitor serum phosphatase levels with prostate cancer.
• Monitor bone density annually when used for osteoporosis prophylaxis.

Patient & Family Education

• Be aware of importance of taking drug exactly as prescribed: Specifically, do not omit, increase, or decrease doses without advice of physician. Know what to do when a dose is missed.
• Review package insert to ensure understanding of estrogen therapy.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug