Pharmacologic class: Estrogen
Therapeutic class: Replacement hormone, antineoplastic, antiosteoporotic
Pregnancy risk category X
Bind to nuclear receptors in responsive tissues (such as female genital organs, breasts, and pituitary gland), enhancing DNA, RNA, and protein synthesis. In androgen-dependent prostate cancer, compete for androgen receptor sites, inhibiting androgen activity. Also decrease pituitary release of folliclestimulating hormone and luteinizing hormone.
Tablets: 0.3 mg, 0.625 mg, 1.25 mg, 2.5 mg
Indications and dosages
➣ Moderate to severe vasomotor symptoms or atrophic vaginitis
Adults: 0.3 to 1.25 mg P.O. daily, adjusted to lowest effective dosage; usually given in cycles of 3 weeks on,1 week off
➣ Female hypogonadism
Adults: 2.5 to 7.5 mg P.O. daily in divided doses for 20 days, followed by 10-day rest period. If no bleeding occurs, repeat same dosing schedule. If bleeding occurs before end of rest period, start 20-day estrogen-progestin cycle, with progestin P.O. given during last 5 days of estrogen therapy.
➣ Inoperable prostate cancer
Adults: 1.25 to 2.5 mg P.O. t.i.d.
➣ Selected breast cancers (inoperable, progressing)
Adults: 10 mg P.O. t.i.d. for at least 3 months
➣ Prevention of osteoporosis
Adults: Initially, 0.3 mg P.O. daily, increased as needed to a maximum of 1.25 mg/day
• Hypersensitivity to drug or its components
• Thromboembolic disease (current or previous)
• Undiagnosed vaginal bleeding
• Breast and reproductive cancers (except metastatic disease)
• Estrogen-dependent neoplasms
Use cautiously in:
• cardiovascular disease, severe hepatic or renal disease, asthma, bone disease, migraines, seizures, breast nodules, fibrocystic breasts
• family history of breast or genital tract cancer
• breastfeeding patients.
• Administer with food or fluids.
• Give cyclically as prescribed, except when used palliatively for cancer treatment.
CNS: headache, dizziness, lethargy, depression, asthenia, paresthesia, syncope, increased risk of cerebrovascular accident (CVA), seizures
CV: hypertension, chest pain, myocardial infarction (MI), thromboembolism
EENT: contact lens intolerance, worsening of myopia or astigmatism, otitis media, sinusitis, rhinitis, pharyngitis
GI: nausea, vomiting, diarrhea, dyspepsia, flatulence, gastritis, gastroenteritis, enlarged abdomen, hemorrhoids, colitis, gallbladder disease, anorexia, pancreatitis
GU: urinary incontinence, dysuria, amenorrhea, dysmenorrhea, endometrial hyperplasia, urinary tract infection, leukorrhea, vaginal discomfort or pain, vaginal hemorrhage, genital eruptions, gynecomastia, breast tenderness, breast enlargement or secretion, reduced libido, erectile dysfunction, testicular atrophy, increased risk of breast cancer, endometrial cancer, hemolytic uremic syndrome
Hepatic: cholestatic jaundice, hepatic adenoma
Metabolic: hyperglycemia, hypercalcemia, sodium and fluid retention, reduced carbohydrate tolerance
Musculoskeletal: leg cramps, back pain, skeletal pain
Respiratory: upper respiratory tract infection, bronchitis, pulmonary embolism
Skin: acne, increased pigmentation, urticaria, pruritus, erythema nodosum, hemorrhagic eruption, alopecia, hirsutism
Other: increased appetite, weight changes, edema, flulike symptoms, hypersensitivity reactions
Drug-drug. Corticosteroids: enhanced corticosteroid effects
CYP450 inducers (such as barbiturates, rifampin): decreased estrogen efficacy
Hypoglycemics, warfarin: altered requirement for these drugs
Phenytoin: loss of seizure control
Tamoxifen: interference with tamoxifen efficacy
Tricyclic antidepressants: reduced antidepressant effect
Drug-diagnostic tests. Antithrombin III, folate, low-density lipoproteins, pyridoxine, total cholesterol, urine pregnanediol: decreased values
Cortisol; factors VII, VIII, IX, and X; glucose; high-density lipoproteins; phospholipids; prolactin; prothrombin; sodium; triglycerides: increased values
Metyrapone test: false decrease
Thyroid function tests: false interpretation
Drug-food. Caffeine: increased caffeine blood level
Drug-herbs. Black cohosh: increased risk of adverse reactions
Red clover: interference with estrogen therapy
Saw palmetto: antiestrogenic effects St. John's wort: decreased drug blood level and effects
Drug-behaviors. Smoking: increased risk of adverse cardiovascular reactions
• Monitor fluid intake and output, and weigh patient daily.
• Evaluate patient for breast tenderness and swelling. As needed, administer analgesics and apply cool compresses.
☞ Know that drug increases risk of thromboembolism, CVA, and MI.
• Monitor liver function test results, and assess abdomen for enlarged liver.
• Check serum phosphatase level in patients with prostate cancer, and adjust dosage as appropriate.
• Monitor calcium, glucose, and folic acid levels.
☞ Teach patient to recognize and immediately report signs and symptoms of thromboembolism.
☞ Caution patient not to take drug if she is or plans to become pregnant.
• Teach patient how to perform breast self-examination. Emphasize importance of monthly checks.
• Tell patient to report breakthrough vaginal bleeding.
• Mention that drug may cause contact lens intolerance. Advise patient to report vision changes.
• Inform male patient that drug may cause gynecomastia.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.