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enzalutamide (Rx)Brand and Other Names:Xtandi

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

capsule

  • 40mg
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Prostate Cancer

Androgen receptor inhibitor indicated for the treatment of metastatic castration-resistant prostate cancer in patients who have not received chemotherapy and those who have previously received docetaxel

160 mg PO qDay

Dosage Modifications

≥Grade 3 toxicity or an intolerable side effect: Withhold dose for 1 week or until symptoms improve to ≤Grade 2, then resume at the same or a reduced dose (120 mg or 80 mg), if warranted

Concomitant strong CYP2C8 inhibitors

  • Avoided if possible
  • If must be coadministered with a strong CYP2C8 inhibitor, reduce enzalutamide dose to 80 mg qDay
  • If coadministration of the strong inhibitor is discontinued, re-establish enzalutamide to the dose used prior to initiation of the strong CYP2C8 inhibitor

Dosing Considerations

May administer with or without food

Swallow capsule whole; do not chew, dissolve, or open the capsules

Not indicated in this population

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Interactions

Interaction Checker

enzalutamide 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%

            Asthenic conditions (50.6%)

            Back pain (26.4%)

            Diarrhea (21.8%)

            Arthralgia (20.5%)

            Hot flush (20.3%)

            Neutropenia, all grades (15%)

            Musculoskeletal pain (15%)

            Peripheral edema (15.4%)

            Headache (12.1%)

            URI (10.9%)

            1-10%

            Muscular weakness (9.8%)

            Dizziness (9.5%)

            Insomnia (8.8%)

            Pneumonia/bronchitis (8.5%)

            Spinal cord compression (7.4%)

            Hematuria (6.9%)

            Paresthesia (6.6%)

            Anxiety (6.5%)

            Hypertension (6.4%)

            Pollakiuria (4.8%)

            Fall (4.6%)

            Mental impairment (4.3%)

            Hypoesthesia (4%)

            Nonpathologic fracture (4%)

            Pruritus (3.8%)

            Dry skin (3.5%)

            Epistaxis (3.3%)

            Hallucinations (1.6%)

            Neutropenia, grades III/IV (1%)

            <1%

            Seizures (0.9%)

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            Warnings

            Contraindications

            Pregnancy; not indicated for use in women

            Cautions

            Because of risk of seizure associated with XTANDI use, advise patients of risk of engaging in activities where sudden loss of consciousness could cause serious harm to themselves or others; permanently discontinue therapy in patients who develop seizure during treatment

            CYP2C8 substrate; avoid coadministration with strong CYP2C8 inhibitors (see Dosage Modifications)

            Enzalutamide is a strong CYP3A4 inducer and a moderate CYP2C9 and CYP2C19 inducer; shown to reduce the plasma exposure to midazolam (CYP3A4 substrate), warfarin (CYP2C9 substrate), and omeprazole (CYP2C19 substrate); caution if coadministered with narrow therapeutic index drugs that are substrates of the aforementioned CYP isoenzymes

            Posterior reversible encephalopathy syndrome (PRES) reported with use; discontinue therapy in patients who develop PRES

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            Pregnancy & Lactation

            Pregnancy Category: X

            Not indicated for use in women

            Can cause fetal harm when administered to a pregnant woman based on its mechanism of action

            Lactation: Unknown whether distributed in breast milk

            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

            Androgen receptor inhibitor; competitively inhibits androgen binding to androgen receptors; also inhibits androgen receptor nuclear translocation and interaction with DNA resulting in decreased proliferation and induced cell death

            Major metabolite, N-desmethyl enzalutamide, exhibited similar in vitro activity to enzalutamide

            Absorption

            Peak Plasma Time: 1 hr

            Peak Plasma Concentration (steady-state): 16.6 mcg/mL (parent compound); 12.7 mcg/mL (active metabolite)

            Steady-state achieved by Day 28

            Distribution

            Protein Bound: 97-98% (parent compound); 95% (active metabolite)

            Vd: 110 L

            Metabolism

            Metabolized by liver by CYP2C8 and CYP3A4; CYP2C8 is primarily responsible for the formation of the active metabolite (N-desmethyl enzalutamide)

            Metabolites: N-desmethyl enzalutamide (active); carboxylic acid metabolite (inactive)

            Strong CYP3A4 inducer; CYP2C9 and CYP2C19 moderate inducer

            Elimination

            Excretion: 14% feces, 71% urine (as inactive metabolites)

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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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