letrozole (Rx)

Brand and Other Names:Femara
  • Print

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 2.5mg
more...

Breast Cancer

Adjuvant treatment of early breast cancer

  • Indicated for adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer
  • 2.5 mg PO qDay

Extended adjuvant treatment of early breast cancer

  • Indicated for extended adjuvant treatment of early breast cancer in postmenopausal women, who have received 5 yr of adjuvant tamoxifen therapy; effectiveness of letrozole in extended adjuvant treatment of early breast cancer is based on an analysis of disease-free survival in patients treated for a median of 60 months
  • 2.5 mg PO qDay

First and second-line treatment of advanced breast cancer

  • Indicated for first-line treatment of postmenopausal women with hormone receptor positive or unknown, locally advanced or metastatic breast cancer; also indicated for treatment of advanced breast cancer in postmenopausal women with disease progression following antiestrogen therapy
  • 2.5 mg PO qDay; continue until tumor progression is evident

Dosage Modifications

Renal impairment

  • Mild-to-moderate (CrCl ≥30 mL/min): No dose adjustment necessary
  • Severe (CrCl ≥10 to <30 mL/min): No dose adjustment necessary

Hepatic impairment

  • Mild-to-moderate: No dose adjustment necessary
  • Patients with cirrhosis and severe hepatic dysfunction: Reduce dose by 50% (ie, 2.5 mg every other day)
  • Noncirrhotic patients with elevated bilirubin levels have not been studied

Ovarian Epithelial Cancer (Off-label)

2.5 mg PO qDay

Safety and efficacy not established

Next:

Interactions

Interaction Checker

and letrozole

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 
            Previous
            Next:

            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

            Previous
            Next:

            Warnings

            Contraindications

            Hypersensitivity

            Pregnancy, premenopausal women

            Cautions

            Use caution in liver impairment

            May cause dizziness, somnolence and fatigue

            May increase total serum cholesterol

            Increased 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
            Previous
            Next:

            Pregnancy & Lactation

            Pregnancy

            Based on post-marketing reports, findings from animal studies and mechanism of action, therapy can cause fetal harm and is contraindicated for use in pregnant women; in post-marketing reports, use during pregnancy resulted in cases of spontaneous abortions and congenital birth defects; however, data are insufficient to inform a drug-associated risk

            Contraception

            • Advise females of reproductive potential to use effective contraception during treatment and for at least 3 weeks after last dose

            Infertility

            • Therapy may impair fertility in females and males of reproductive potential

            Lactation

            Not known if therapy is present in human milk; there are no data on effects on breastfed infant or milk production; exposure of lactating rats to drug was associated with impaired reproductive performance of male offspring; because of potential for serious adverse reactions in breastfed infants, advise lactating women not to breastfeed while receiving therapy and for at least 3 weeks after last dose

            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.

            more...
            Previous
            Next:

            Pharmacology

            Mechanism of Action

            Aromatase inhibitor - blocks conversion of androgens to estrogens by binding to the heme group of aromatase enzyme, which in turn inhibits its activity

            Distribution

            Vd: 1.9 L/kg

            Metabolism

            Metabolites: 4,4'-methanol-bisbenzonitrile via CYP3A4 and 2A6 activity

            Enzymes inhibited: Aromatase

            Elimination

            Half-life: 2 days

            Excretion: Urine 90%

            Previous
            Next:

            Administration

            Oral Administration

            May take with or without food

            Previous
            Next:

            Images

            Previous
            Next:

            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            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.
            Additional Offers
            Email to Patient

            From:

            To:

            The recipient will receive more details and instructions to access this offer.

            By clicking send, you acknowledge that you have permission to email the recipient with this information.

            Email Forms to Patient

            From:

            To:

            The recipient will receive more details and instructions to access this offer.

            By clicking send, you acknowledge that you have permission to email the recipient with this information.

            Previous
            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.