Premarin(redirected from Pregnant mare's urine)
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C.E.S. (CA), Congest (CA), Premarin, Premarin Intravenous
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 follicle-stimulating and luteinizing hormones.
Powder for injection: 25 mg/5 ml
Tablets: 0.3 mg, 0.625 mg, 0.9 mg, 1.25 mg
Vaginal cream: 0.625 mg/g
⊘Indications and dosages
➣ Ovariectomy; primary ovarian failure
Adults: 1.25 mg P.O. daily continuously or in cycles of 3 weeks on and 1 week off
➣ Osteoporosis and menopausal symptoms
Adults: 0.3 to 1.25 mg P.O. daily continuously or in cycles of 3 weeks on and 1 week off
➣ Female hypogonadism
Adults: 0.3 to 0.625 mg P.O. daily, given in cycles of 3 weeks on and 1 week off
➣ Inoperable breast cancer in men and postmenopausal women
Adults: 10 mg P.O. t.i.d. for 3 months or more
➣ Inoperable prostate carcinoma
Adults: 1.25 to 2.5 mg P.O. t.i.d.
➣ Uterine bleeding caused by hormonal imbalance
Adults: 25 mg I.M. or I.V., repeated in 6 to 12 hours if necessary
➣ Atrophic vaginitis, kraurosis vulvae
Adults: 0.5 to 2 g (vaginal cream) intravaginally daily in cycles of 3 weeks on and 1 week off
➣ Moderate to severe dyspareunia
Adults: 0.5 g (vaginal cream) intravaginally daily in cycles of 3 weeks on and 1 week off
• Hypersensitivity to drug or its components
• Thromboembolic disease (current or previous)
• Undiagnosed vaginal bleeding
• Breast or reproductive system cancer (except metastatic disease)
• Estrogen-dependent neoplasms
Use cautiously in:
• cardiovascular disease, severe hepatic or renal disease, asthma, bone disease, migraine, seizures, breast disease
• family history of breast or genital tract cancer
• breastfeeding patients.
• Know that drug is compatible with dextrose 5% in water and normal saline solution.
CNS: headache, dizziness, lethargy, depression, asthenia, paresthesia, syncope, 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, abdominal cramps, bloating, enlarged abdomen, dyspepsia, flatulence, gastritis, gastroenteritis, hemorrhoids, colitis, gallbladder disease, anorexia, pancreatitis
GU: urinary incontinence, dysuria, urinary tract infection, amenorrhea, dysmenorrhea, endometrial hyperplasia, vaginal candidiasis, leukorrhea, 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, oily skin, pigmentation changes, urticaria, pruritus, erythema nodosum, hemorrhagic eruption, skin hypertrophy, hirsutism, alopecia, erythema multiforme
Other: edema, weight changes, increased appetite, hypersensitivity reaction, angioedema
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 effects
Tricyclic antidepressants: reduced antidepressant effects
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 effects
Saw palmetto: antiestrogenic effects St. John's wort: decreased drug blood level and effects
Drug-behaviors.Smoking: increased risk of adverse cardiovascular reactions
• Monitor liver function test results and assess abdomen for enlarged liver.
• Evaluate patient for breast tenderness and swelling. As needed, give analgesics and apply cool compresses.
• Monitor fluid intake and output, and weigh patient daily.
☞ Know that drug increases risk of thromboembolism, CVA, and MI.
• Be aware that exogenous estrogens may induce or exacerbate symptoms of angioedema, particularly in women with hereditary angioedema.
• Check serum phosphatase level in patients with prostate cancer.
• Monitor calcium, glucose, and folic acid levels.
• Evaluate bone density annually.
☞ Teach patient to recognize and report signs and symptoms of thromboembolism.
☞ Caution patient not to take drug if she is or plans to become pregnant.
• Tell patient to report breakthrough vaginal bleeding.
• Recommend that patient have routine breast examinations.
• 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.