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letrozole (Rx)Brand and Other Names:Femara

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 2.5mg
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Breast Cancer

2.5 PO qDay, until tumor progression evident

Ovarian Epithelial Cancer (Off-label)

2.5 mg PO qDay

Other Indications & Uses

Adjuvant treatment of postmenopausal, hormone receptor positive, early breast cancer

Extended adjuvant treatment of early breast cancer in post-menopausal women after 5 years of adjuvant tamoxifen

First and second-line treatment of postmenopausal women with hormone receptor positive or unknown advanced breast cancer

Off-label: ovulation induction

Safety and efficacy not established

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Interactions

Interaction Checker

letrozole 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%

            Diaphoresis (24%)

            Bone pain (22%)

            Hot flashes (19%)

            Back pain (18%)

            Dyspnea (18%)

            Nausea (17%)

            Night sweats (14%)

            Cough (13%)

            Fatigue (13%)

            1-10%

            Constipation (10%)

            Hypertension (8%)

            Chest pain (8%)

            Diarrhea (8%)

            Decr wt (7%)

            Edema (7%)

            Breast pain (7%)

            Bone fractures (6%)

            UTI (6%)

            Hypercalcemia (5%)

            Headache (4%)

            Weakness (4%)

            Vomiting (3%)

            Osteoporosis (2%)

            <1%

            Blurred vision

            Increased hepatic enzyme levels

            Postmarketing Reports

            Blurred vision

            Increased hepatic enzymes

            Hepatitis

            Angioedema

            Anaphylactic reactions

            Toxic epidermal necrolysis

            Erythema multiforme

            Carpal tunnel syndrome

            Trigger finger

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            Warnings

            Contraindications

            Hypersensitivity

            Pregnancy, premenopausal women

            Cautions

            Liver impairment

            Incr risk of osteoporosis

            Avoid concomitant estrogens

            Risk of birth defects if given to pregnant women

            • Used off-label to induce ovulation
            • Health Canada & Novartis Canada warned against such use
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            Pregnancy & Lactation

            Pregnancy Category: D

            Lactation: not known if excreted in breast milk (for post-menopausal women)

            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

            Aromatase inhibitor - blocks conversion of adrostenedione to estrone

            Distribution

            Vd: 1.9 L/kg

            Metabolism

            Metabolites: 4,4'-methanol-bisbenzonitrile

            Enzymes inhibited: Aromatase

            Elimination

            Half-life: 2 days

            Excretion: Urine 90%

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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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