anastrozole (Rx)

Brand and Other Names:Arimidex
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 1mg

Breast Cancer

Postmenopausal women

Advanced

  • 1 mg PO once daily; continue until tumor progression

Early

  • Adjuvant treatment: 1 mg PO qDay; optimal duration unknown; 5 years in clinical trials

Administration

May be taken with or without food

Hepatic Impairment

Mild-to-moderate impairment or stable hepatic cirrhosis: Dose adjustment not necessary

Severe hepatic impairment: Not studied

Use not recommended

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Interactions

Interaction Checker

and anastrozole

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    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

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            Contraindicated (0)

              Serious - Use Alternative (10)

              • bazedoxifene/conjugated estrogens

                bazedoxifene/conjugated estrogens decreases effects of anastrozole by pharmacodynamic antagonism. Contraindicated.

              • conjugated estrogens

                conjugated estrogens decreases effects of anastrozole by pharmacodynamic antagonism. Contraindicated.

              • estradiol

                estradiol decreases effects of anastrozole by pharmacodynamic antagonism. Contraindicated. Estrogen may diminish the pharmacologic action of anastrozole. Coadministration not recommended.

              • estrogens conjugated synthetic

                estrogens conjugated synthetic decreases effects of anastrozole by pharmacodynamic antagonism. Contraindicated. Estrogen may diminish the pharmacologic action of anastrozole. Coadministration not recommended.

              • estrogens esterified

                estrogens esterified decreases effects of anastrozole by pharmacodynamic antagonism. Contraindicated. Estrogen may diminish the pharmacologic action of anastrozole. Coadministration not recommended.

              • estropipate

                estropipate decreases effects of anastrozole by pharmacodynamic antagonism. Contraindicated. Estrogen may diminish the pharmacologic action of anastrozole. Coadministration not recommended.

              • ethinylestradiol

                ethinylestradiol decreases effects of anastrozole by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Anastrozole should not be given concurrently with any estrogens or estrogen-containing products.

              • lonafarnib

                anastrozole will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

              • palifermin

                palifermin increases toxicity of anastrozole by Other (see comment). Avoid or Use Alternate Drug. Comment: Palifermin should not be administered within 24 hr before, during infusion of, or within 24 hr after administration of antineoplastic agents. Coadministration of palifermin within 24 hr of chemotherapy resulted in increased severity and duration of oral mucositis.

              • tamoxifen

                tamoxifen decreases levels of anastrozole by unspecified interaction mechanism. Contraindicated. Anastrozole and tamoxifen should not be administered together.

              Monitor Closely (16)

              • atogepant

                anastrozole will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • avapritinib

                anastrozole will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • axitinib

                anastrozole increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • cholera vaccine

                anastrozole decreases effects of cholera vaccine by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs and corticosteroids (used in greater than physiologic doses), may reduce the immune response to cholera vaccine.

              • conjugated estrogens, vaginal

                conjugated estrogens, vaginal decreases effects of anastrozole by pharmacodynamic antagonism. Modify Therapy/Monitor Closely.

              • dengue vaccine

                anastrozole decreases effects of dengue vaccine by immunosuppressive effects; risk of infection. Use Caution/Monitor. Immunosuppressive therapies (eg, irradiation, antimetabolites, alkylating agents, cytotoxic drugs, corticosteroids [greater than physiologic doses]) may reduce immune response to dengue vaccine.

              • finerenone

                anastrozole will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

              • flibanserin

                anastrozole will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

              • isavuconazonium sulfate

                anastrozole will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • ivacaftor

                anastrozole increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

              • lemborexant

                anastrozole will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

              • lomitapide

                anastrozole increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

              • midazolam intranasal

                anastrozole will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.

              • siponimod

                siponimod and anastrozole both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immunosuppressive effects during such therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs to avoid unintended additive immunosuppressive effects.

              • tazemetostat

                anastrozole will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              • tinidazole

                anastrozole will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              Minor (1)

              • ruxolitinib

                anastrozole will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

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              Adverse Effects

              >10%

              Hot flashes (12-36%)

              Vasodilation (25-36%)

              Fatigue (19%)

              Mood disturbances (19%)

              Nausea and vomiting (19%)

              Weakness (16-19%)

              Arthritis (17%)

              Pain (17%)

              Arthralgia (2-15%)

              Pharyngitis (14%)

              Depression (13%)

              Hypertension (2-13%)

              Bone pain (11%)

              Increased cough (11%)

              Osteoporosis (11%)

              Rash (8-11%)

              1-10%

              Accidental injury (10%)

              Back pain (10%)

              Fracture (10%)

              Headache (10%)

              Insomnia (10%)

              Peripheral edema (10%)

              Dyspnea (8-10%)

              Abdominal pain (9%)

              Infection (9%)

              Lymphedema (9%)

              Diarrhea (8-9%)

              Constipation (7-9%)

              Breast pain (8%)

              Dizziness (8%)

              Urinary tract infection (8%)

              Chest pain (7%)

              Dyspepsia (7%)

              Paresthesia (5-7%)

              Anxiety (6%)

              Cataracts (6%)

              Flu syndrome (6%)

              Sinusitis (6%)

              Vulvovaginitis (6%)

              Xerostomia (6%)

              Breast neoplasm (5%)

              Bronchitis (5%)

              Cyst (5%)

              Diaphoresis (5%)

              Neoplasm (5%)

              Vaginal bleeding (5%)

              Fractures of spine, hip, or wrist (4%)

              Ischemic cardiovascular disease (4%)

              Vaginal hemorrhage (4%)

              Vaginitis (4%)

              Leukorrhea (3-4%)

              Deep vein thrombosis (2%)

              Endometrial cancer (intact uterus at baseline) (2%)

              Ischemic cerebrovascular event (2%)

              Weight gain (2%)

              Lethargy (1%)

              Postmarketing Reports

              Hepatitis; increased alkaline phosphatase, aminotransferases, gamma-glutamyl transferase, and bilirubin

              Allergic reactions, including angioedema, urticaria, and anaphylaxis

              Rash, including mucocutaneous disorders (eg, erythema multiforme, Stevens-Johnson syndrome)

              Myalgia, trigger finger, and hypercalcemia (with or without increase in parathyroid hormone)

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              Warnings

              Contraindications

              Hypersensitivity

              May cause fetal harm or loss; use is contraindicated in women who are or may become pregnant

              Cautions

              Increased incidence of ischemic cardiovascular events in women with preexisting ischemic heart disease; use only if benefits greatly outweigh risks

              Decreases lumbar spine and total hip bone mineral density; increased risk of fractures and osteoporosis; concurrent use with bisphosphonates may be useful in patients at risk for fractures; follow available guidelines for bone mineral density management in postmenopausal women; patients with preexisting osteopenia are at higher risk for developing osteoporosis

              Elevated serum cholesterol reported; monitor closely; use with caution in patients with hyperlipidemias; monitor and manage cholesterol levels with current guidelines for patients with LDL elevations

              Affords no clinical benefit to premenopausal women with breast cancer

              Increased risk of ischemic cardiovascular events in patients with pre-existing ischemic cardiac disease

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              Pregnancy & Lactation

              Pregnancy

              Based on findings from animal studies and mechanism of action, therapy may cause fetal harm when administered to pregnant woman; there are no studies on use in pregnant women

              Advise pregnant women and females of reproductive potential of potential risk to a fetus

              Verify pregnancy status of females of reproductive potential prior to initiation of therapy

              Based on animal studies, therapy can cause fetal harm when administered to a pregnant woman

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

              Based on studies in female animals, treatment may impair fertility in females of reproductive potential

              Animal data

              • Anastrozole caused embryo-fetal toxicities in rats at maternal exposure that were 9 times the human clinical exposure, based on area under the curve (AUC); in rabbits, anastrozole caused pregnancy failure at doses equal to or greater than 16 times the recommended human dose on a mg/m2 basis

              Lactation

              There are no data on presence of drug or metabolites in human milk, or effects on breast-fed child or on milk production; because many drugs are excreted in human milk and because of tumorigenicity shown for anastrozole in animal studies, or potential for serious adverse reactions in breast-fed child from treatment, advise lactating women not to breastfeed during treatment and for 2 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.

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              Pharmacology

              Mechanism of Action

              Selective nonsteroidal aromatase inhibitor; prevents conversion of androstenedione to estrone and estradiol in peripheral tissues, thereby significantly lowering serum estradiol concentrations; has no effect on adrenal corticosteroids or aldosterone

              Absorption

              Peak plasma concentration: 2 hr without food; 5 hr with food

              Onset: 24 hr (70% reduction); 2 weeks (80% reduction)

              Time to steady-state levels: 7 days

              Distribution

              Protein bound: 40%

              Metabolism

              Metabolized in liver via N-dealkylation, hydroxylation, and glucuronidation (85%)

              Metabolite: Triazole (inactive)

              Enzymes inhibited: CYP1A2, CYP2C9, CYP3A4 (at high concentrations; inhibition not significant at usual dose)

              Elimination

              Half-life: 50 hr

              Dialyzable: Yes

              Excretion: Urine (10%)

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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Arimidex oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet
              anastrozole oral
              -
              1 mg tablet

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              anastrozole oral

              ANASTROZOLE - ORAL

              (an-AS-troe-zole)

              COMMON BRAND NAME(S): Arimidex

              USES: Anastrozole is used to treat breast cancer in women after menopause. Some breast cancers are made to grow faster by a natural hormone called estrogen. Anastrozole decreases the amount of estrogen the body makes and helps to slow or reverse the growth of these breast cancers.

              HOW TO USE: Read the Patient Information Leaflet if available from your pharmacist before you start taking anastrozole and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth with or without food as directed by your doctor, usually once a day.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

              SIDE EFFECTS: Hot flashes, headache, trouble sleeping, dizziness, stomach upset, nausea/vomiting, constipation, diarrhea, loss of appetite, weight gain, tiredness/weakness, increased coughing, or sore throat may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: bone pain, easily broken bones, joint stiffness/pain, muscle pain/stiffness, mental/mood changes (such as depression), numb/tingling skin, swelling hands/ankle/feet, shortness of breath, unusual vaginal discharge/bleeding/burning/itching/odor, pain/redness/swelling of arms or legs, vision changes, signs of liver disease (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine).Get medical help right away if you have any very serious side effects, including: chest/jaw/left arm pain, confusion, trouble speaking, weakness on one side of the body.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before taking anastrozole, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart disease (such as history of heart attack), bone loss (osteoporosis), liver disease, high blood pressure, blood clots.This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.Anastrozole is used mainly in women after menopause. If you have not gone through menopause, this medication must not be used during pregnancy. It may harm an unborn baby. Discuss the use of reliable forms of birth control (such as latex condoms) while taking this medication and for at least 3 weeks after stopping treatment with your doctor. Products containing estrogen (such as birth control pills) should not be used. If you become pregnant or think you may be pregnant, tell your doctor right away.It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug and for at least 2 weeks after stopping treatment is not recommended. Consult your doctor before breast-feeding.

              DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug are: estrogens, tamoxifen, tibolone.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

              NOTES: Do not share this medication with others.Lab and/or medical tests (such as cholesterol levels, liver function, bone density) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.This medication can increase the risk of bone loss (osteoporosis). Talk with your doctor about your risk, and about available treatments for osteoporosis. Lifestyle changes that reduce the risk of bone loss include doing weight-bearing exercise, getting enough calcium and vitamin D, stopping smoking, and limiting alcohol.

              MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

              STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

              Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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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.
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              NC NOT COVERED – Drugs that are not covered by the plan.
              Code Definition
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              Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.