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conjugated estrogens (Rx)Brand and Other Names:Premarin

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 0.3mg
  • 0.45mg
  • 0.625mg
  • 0.9mg
  • 1.25mg

powder for injection

  • 25mg
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Menopausal Vasomotor Symptoms, Atrophic Vaginitis/Kraurosis Vulvae

0.3 mg PO once daily in either continuous daily regimen or cyclic regimen (25 days on, 5 days off); adjusted PRN; use lowest dose that control symptoms; may be given daily if medical assessment warrants it

Female Hypogonadism

0.3-0.625 mg PO once daily in cyclic regimen (3 weeks on, 1 week off); may be titrated every 6-12 months; adjusted PRN; add progestin treatment should be added to maintain bone mineral density once skeletal maturity achieved

Osteoporosis

Prophylaxis

0.3 mg PO once daily in cyclic regimen (25 days on, 5 days off); adjusted PRN based on clinical response; may be given daily if medical assessment warrants it; administer lowest effective dose

May also be used in combination with medroxyprogesterone acetate

Prostate Cancer

Palliation only

1.25-2.5 mg PO q8hr

Abnormal Uterine Bleeding

25 mg IV/IM; repeated in 6-12 hours PRN or 25 mg IV repeated q4hr for 24 hr; if no response after 2 doses, re-evaluate therapy

Alternative regimen: 10-20 mg/day PO divided q4hr

May administer low dose medroxyprogesterone acetate with therapy or following therapy

Cyclic therapy: 25 days on, 5 days off; either 3 weeks on, 1 week off

Female Castration/Primary Ovarian Failure

1.25 mg PO once daily in cyclic regimen (25 days on, 5 days off); adjusted PRN; administer lowest effective dose

Breast Cancer Palliation

Metastatic disease in selected patients (males and females):10 mg PO q8hr for ≥3 months

Uremic Bleeding (Off-label)

0.6 mg/kg/day IV for 5 days

Safety and efficacy not established

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Interactions

Interaction Checker

conjugated estrogens and

No Results

     
     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            >10%

            Abdominal pain (15-17%)

            Back pain (13-14%)

            Breast enlargement

            Breast tenderness (7-12%)

            Headache (26-32%)

            Arthralgia (7-14%)

            Pharyngitis (10-12%)

            Sinusitis (6-11%)

            Diarrhea (6-7%)

            1-10%

            Depression (5-8%)

            Dizziness (4-6%)

            Nervousness (2-5%)

            Flatulence (6-7%)

            Vaginitis (5-7%)

            Leukorrhea (4-7%)

            Leg cramps (3-7%)

            Increased cough (4-7%)

            Pruritus (4-5%)

            Frequency Not Defined

            Amenorrhea

            Breakthrough bleeding

            Corneal curvation change

            Melasma

            Spotting

            Vaginal moniliasis

            Weight changes

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            Warnings

            Black Box Warnings

            Estrogens increase risk of endometrial cancer

            • Close clinical surveillance of all women taking estrogens is important
            • Adequate diagnostic measures, including endometrial sampling when indicated, should be undertaken to rule out malignancy in all cases of undiagnosed persistent or recurring abnormal vaginal bleeding
            • There is no evidence that the use of "natural" estrogens results in a different endometrial risk profile than the use of synthetic estrogens at equivalent estrogen doses

            Increased risk of breast cancer

            • Using conjugated estrogens in combination with medroxyprogesterone increases risk of invasive breast cancer

            Cardiovascular risks

            • Estrogens with or without progestins should not be used to prevent cardiovascular disease
            • Estrogens plus progestins: Women’s Health Initiative (WHI) Estrogen Plus Progestin substudy reported increased risks of myocardial infarction (MI), stroke, invasive breast cancer, pulmonary embolism (PE), and deep vein thrombosis (DVT) in postmenopausal women (aged 50-79 years) during 5.6 years of treatment with daily PO conjugated estrogens (0.625 mg) combined with medroxyprogesterone acetate (2.5 mg) in comparison with placebo
            • Estrogens alone: A substudy of the WHI study reported increased risk for stroke and DVT in postmenopausal women (aged 50-79 years) during 6.8 years of treatment with daily PO conjugated estrogens (0.625 mg) alone in comparison with placebo

            Dementia risks

            • Estrogens with or without progestins should not be used to prevent dementia
            • Women's Health Initiative Memory Study (WHIMS), a substudy of the WHI study, reported increased risk of developing probable dementia in postmenopausal women aged ≥65 years during 4 years of treatment with daily PO conjugated estrogens (0.625) mg combined with medroxyprogesterone acetate (2.5 mg) in comparison with placebo
            • Estrogens alone: A substudy of the WHIMS reported increased risk of developing probable dementia in postmenopausal women aged ≥65 years during 5.2 years of treatment with daily PO conjugated estrogens (0.625 mg) alone in comparison with placebo
            • Unknown whether these findings apply to younger postmenopausal women

            Dose & duration

            • In the absence of comparable data, these risks should be assumed to be similar for other doses of conjugated estrogens and medroxyprogesterone acetate, as well as for other combinations and dosage forms of estrogens and progestins
            • Because of these risks, estrogens with or without progestins should be prescribed at the lowest effective dosage and for the shortest duration consistent with treatment goals and individual risks

            Contraindications

            Known anaphylactic reaction or angioedema

            Known protein C, protein S, or antithrombin deficiency; other known thrombophilic disorders

            Active or history of breast cancer

            Arterial thromboembolic disease (stroke, MI), thrombophlebitis, DVT/PE, thrombogenic valvular disease

            Liver disease, liver tumors

            Uncontrolled hypertension, diabetes mellitus with vascular involvement, jaundice with previous oral contraceptive use

            Estrogen-dependent neoplasia

            Undiagnosed abnormal vaginal bleeding

            Cautions

            Use caution in diabetes mellitus, hyperlipidemias, hypertension, hypothyroidism, advanced age, hepatic or renal impairment, uterine leiomyomata, porphyria, patients with defects of lipoprotein metabolism, hypertriglyceridemia, ovarian cancer, systemic lupus erhythematosus, exacerbation of endometriosis or other conditions, smoking, diseases exacerbated by fluid retention

            Discontinue if any of the following develop: Jaundice, signs of venous thromboembolism, visual problems (may cause contact lens intolerance), massive blood pressure increase, major surgery or prolonged immobilization occurring in 4 weeks, new migraine, depression, papilledema or retinal vascular lesions observed on examination

            Women with protein C or S deficiency (inherited thrombophilia), may have increased risk of venous thromboembolism

            Conditions exacerbated by fluid retention (asthma, epilepsy, migraines, cardiac or renal dysfunction)

            Risk of hypercalcemia in patients with breast cancer and bone metastases

            Increased risk of ovarian and endometrial cancer

            Long-term postmenopausal estrogen treatment has been associated with increased risk of breast cancer, MI, stroke, DVT/PE, and dementia

            Patients on warfarin or other oral anticoagulants: Estrogens increase thromboembolic risk; increase in anticoagulant dosage may be warranted

            Discontinue therapy if pancreatitis occurs; estrogen compounds generally associated with increased triglyceride levels

            Cases of anaphylaxis and angioedema have been reported; exogenous estrogens may exacerbate symptoms of angioedema in women with hereditary angioedema

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            Pregnancy & Lactation

            Pregnancy category: X

            Lactation: Use controversial; estrogens are excreted into breast milk in small quantities; use with caution

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

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            Pharmacology

            Mechanism of Action

            Replaces endogenous estrogen; important for development and maintenance of female reproductive system and secondary sexual characteristics

            Antiandrogenic effect provides benefit in prostate cancer

            Absorption

            Bioavailability: Readily absorbed from gastrointestinal (GI) tract

            Onset: 2-4 weeks (PO-menopause)

            Peak plasma time: 7 hr (PO)

            Distribution

            Protein bound: 80%

            Metabolism

            Metabolized in liver to inactive sulfates and glucuronides

            Metabolites: Estradiol, estrone, estriol

            Elimination

            Excretion: Mainly in urine as conjugates with small amount of unchanged drug; most estrogens are also excreted in bile and undergo enterohepatic recycling

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            Administration

            IV Incompatibilities

            Additive, syringe, Y-site: Ascorbic acid, acidic solutions, protein hydrolysate

            IV Compatibilities

            Solution: D5W, NS, invert sugar solutions

            Y-site: Heparin/hydrocortisone, potassium chloride, vitamins B and C

            IV Preparation

            Reconstitute with 5 mL of diluent provided

            First withdraw air from vial, then add diluent slowly and aseptically with gentle agitation

            Stable at 2-8°C for 60 days

            Do not use if agent darkens or precipitates

            IV/IM Administration

            IM: Acceptable

            IV: Administer slowly to avoid flushing reaction

            Infusion not recommended; injection into running infusion can be performed

            Storage

            Refrigerate reconstituted injection

            Intact vials are stable for 24 months at room temperature

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            Images

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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