Anastrozole
/api/v1/drug/anastrozoleMechanism of action
Sourced from openFDAThe growth of many cancers of the breast is stimulated or maintained by estrogens. In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol.
Indications
Sourced from openFDA- Anastrozole is an aromatase inhibitor indicated for: Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer ( 1.1 ) First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer ( 1.2 ) Treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy. Patients with ER-negative disease and patients who did not respond to previous tamoxifen therapy rarely responded to anastrozole ( 1.3 ) 1.1 Adjuvant Treatment Anastrozole tablets are indicated for adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer.ICD-10: C50.919
Contraindications
Sourced from openFDA- Hypersensitivity Anastrozole is contraindicated in any patient who has shown a hypersensitivity reaction to the drug or to any of the excipients. Observed reactions include anaphylaxis, angioedema, and urticaria [see Adverse Reactions ( 6.2 )].contraindicated
Dosage & administration
Sourced from openFDAOne 1 mg tablet taken once daily ( 2.1 ) 2.1 Recommended Dose The dose of anastrozole tablet is one 1 mg tablet taken once a day. For patients with advanced breast cancer, anastrozole tablets should be continued until tumor progression. Anastrozole tablets can be taken with or without food. For adjuvant treatment of early breast cancer in postmenopausal women, the optimal duration of therapy is unknown. In the ATAC trial, anastrozole was administered for five years [see Clinical Studies ( 14.1 )]. No dosage adjustment is necessary for patients with renal impairment or for elderly patients [see Use in Specific Populations ( 8.6 )]. 2.2 Patients with Hepatic Impairment No changes in dose are recommended for patients with mild-to-moderate hepatic impairment. Anastrozole has not been studied in patients with severe hepatic impairment [see Use in Specific Populations ( 8.7 )].
Warnings & precautions
Sourced from openFDAIn women with pre-existing ischemic heart disease, an increased incidence of ischemic cardiovascular events occurred with anastrozole use compared to tamoxifen use. Consider risks and benefits. ( 5.1 , 6.1 ) Decreases in bone mineral density may occur. Consider bone mineral density monitoring. ( 5.2 , 6.1 ) Increases in total cholesterol may occur. Consider cholesterol monitoring. ( 5.3 , 6.1 ) Embryo-Fetal Toxicity: Anastrozole may cause fetal harm. Advise patients of the potential risk to a fetus and to use effective contraception. ( 5.4 , 8.1 ) 5.1 Ischemic Cardiovascular Events In women with pre-existing ischemic heart disease, an increased incidence of ischemic cardiovascular events was observed with anastrozole in the ATAC trial (17% of patients on anastrozole and 10% of patients on tamoxifen). Consider risk and benefits of anastrozole therapy in patients with pre-existing ischemic heart disease [see Adverse Reactions ( 6.1 )]. 5.2 Bone Effects Results from the ATAC trial bone substudy at 12 and 24 months demonstrated that patients receiving anastrozole had a mean decrease in both lumbar spine and total hip bone mineral density (BMD) compared to baseline. Patients receiving tamoxifen had a mean increase in both lumbar spine and total hip BMD compared to baseline. Consider bone mineral density monitoring in patients treated with anastrozole [see Adverse Reactions ( 6.1 )] .
Adverse reactions
Sourced from openFDASerious adverse reactions with anastrozole occurring in less than 1 in 10,000 patients, are: 1) skin reactions such as lesions, ulcers, or blisters; 2) allergic reactions with swelling of the face, lips, tongue, and/or throat. This may cause difficulty in swallowing and/or breathing; and 3) changes in blood tests of the liver function, including inflammation of the liver with symptoms that may include a general feeling of not being well, with or without jaundice, liver pain or liver swelling [see Adverse Reactions ( 6.2 )]. Common adverse reactions (occurring with an incidence of ≥10%) in women taking anastrozole included: hot flashes, asthenia, arthritis, pain, arthralgia, hypertension, depression, nausea and vomiting, rash, osteoporosis, fractures, back pain, insomnia, headache, bone pain, peripheral edema, increased cough, dyspnea, pharyngitis and lymphedema. In the ATAC trial, the most common reported adverse reaction (>0.1%) leading to discontinuation of therapy for both treatment groups was hot flashes, although there were fewer patients who discontinued therapy as a result of hot flashes in the anastrozole group. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Use in specific populations
Sourced from openFDALactation: Do not breastfeed. ( 8.2 ) Females and Males of Reproductive Potential: Verify pregnancy status prior to initiation of anastrozole. ( 8.3 ) Pediatric patients: Efficacy has not been demonstrated for pubertal boys of adolescent age with gynecomastia or girls with McCune Albright Syndrome and progressive precocious puberty. ( 8.4 ) 8.1 Pregnancy Risk Summary Based on findings from animal studies and its mechanism of action, anastrozole may cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1) ] . There are no studies of anastrozole use in pregnant women. 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/m 2 basis. Advise pregnant women and females of reproductive potential of the potential risk to a fetus. The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Pharmacokinetics
Sourced from openFDA- Metabolism
- Absorption Inhibition of aromatase activity is primarily due to anastrozole, the parent drug. Absorption of anastrozole is rapid and maximum plasma concentrations typically occur within 2 hours of dosing under fasted conditions.
Overdosage
Sourced from openFDAClinical trials have been conducted with anastrozole, up to 60 mg in a single dose given to healthy male volunteers and up to 10 mg daily given to postmenopausal women with advanced breast cancer; these dosages were tolerated. A single dose of anastrozole that results in life-threatening symptoms has not been established. There is no specific antidote to overdosage and treatment must be symptomatic. In the management of an overdose, consider that multiple agents may have been taken. Vomiting may be induced if the patient is alert. Dialysis may be helpful because anastrozole is not highly protein bound. General supportive care, including frequent monitoring of vital signs and close observation of the patient, is indicated.
Approval history
Sourced from openFDA- Dec 27, 1995NDANDA020541Ani Pharms
- Jun 28, 2010ANDAANDA079220Natco Pharma Ltd
- Jun 28, 2010ANDAANDA078921Zydus Pharms Usa Inc
- Jun 28, 2010ANDAANDA090568Accord Hlthcare
- Jun 28, 2010ANDAANDA078058Teva Pharms
- Nov 9, 2018ANDAANDA206037Beijing Yiling
- Jul 24, 2020ANDAANDA212434Eugia Pharma
FAERS reports
- 1Fatigue3,3409.3%
- 2Arthralgia3,1918.9%
- 3Nausea2,7117.6%
- 4Alopecia2,5577.1%
- 5Diarrhoea2,3306.5%
- 6Pain1,8035.0%
- 7Headache1,7775.0%
- 8Asthenia1,5914.4%
- 9Dyspnoea1,5644.4%
- 10Dizziness1,5024.2%
- 11Hot Flush1,4133.9%
- 12Pain In Extremity1,3903.9%
- 13Malignant Neoplasm Progression1,3583.8%
- 14Vomiting1,3023.6%
- 15Malaise1,2983.6%
Literature
Recent PubMed references pinned to Anastrozole as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.
- All-male production in Nile tilapia (Oreochromis niloticus) through discrete anastrozole immersion: hormonal and histological insights.Fish physiology and biochemistry · 2026 · Katare MB, Mogalekar HS, Swami AM, et al.PMID 42171893DOI 10.1007/s10695-026-01707-y
- Outcomes of Anastrozole, Letrozole, and Exemestane in Patients With Postmenopausal Breast Cancer.JAMA network open · 2025 · Dumas E, Hamy AS, Wanis KN, et al.PMID 41632158DOI 10.1001/jamanetworkopen.2025.50842
- Biomarkers of response to neoadjuvant palbociclib plus anastrozole in endocrine-resistant estrogen receptor-positive/HER2-negative breast cancer: a phase 2 trial.Nature communications · 2026 · Kong T, Mabry A, Highkin M, et al.PMID 41593097DOI 10.1038/s41467-026-68570-6
- Induction of masculinization in Nile Tilapia (Oreochromis niloticus) through Dietary Administration of Anastrozole: Histological and Hormonal Insights.Fish physiology and biochemistry · 2026 · M B K, H S M, A M S, et al.PMID 41537903DOI 10.1007/s10695-026-01637-9
- UHPLC Method Development for the Trace Level Quantification of Anastrozole and Its Process-Related Impurities Using Design of Experiments.Biomedical chromatography : BMC · 2026 · Tadisetty NR, Yanamandra R, Pradhan S, et al.PMID 41449109DOI 10.1002/bmc.70279
- Critical role of the mast cell/tryptase/PAR2 axis in anastrozole-induced pain.British journal of pharmacology · 2026 · Fialho MFP, Tonello R, Brum ES, et al.PMID 41391836DOI 10.1111/bph.70280
- Possible role of anastrozole-induced hormonal alterations in pathogenesis of mammary apocrine carcinoma and follicular lymphoma: a case report and review of the literature.Journal of medical case reports · 2025 · Kitagawa Y, Nassiri M, Mesa H, et al.PMID 41024216DOI 10.1186/s13256-025-05553-z
- Comparison of Effects of Chorionic Gonadotropin Alfa and Anastrozole on Sperm Retrieval Rate in Patients with Non-Mosaic Klinefelter Syndrome Following Microdissection Testicular Sperm Extraction.Medicina (Kaunas, Lithuania) · 2025 · Pelit ES, Danacıoğlu YO, Katı B, et al.PMID 40142278DOI 10.3390/medicina61030467
Clinical trials
The 10 most recently updated of 483 ClinicalTrials.gov registrations naming Anastrozole as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.
- Testing Whether Hormone Therapy With Ribociclib is as Effective as Chemotherapy Followed by Hormone Therapy With Ribociclib for the Treatment of High Anatomic Stage Breast Cancer With Low Recurrence Risk, The RxFINE-Low TrialRecruiting · Phase 3 · Interventional · 1,978 enrolled · National Cancer Institute (NCI)NCT07391774updated 2026-06-12
- Hormone Therapy With or Without Combination Chemotherapy in Treating Women Who Have Undergone Surgery for Node-Negative Breast Cancer (The TAILORx Trial)Active not recruiting · Phase 3 · Interventional · 10,273 enrolled · National Cancer Institute (NCI)NCT00310180updated 2026-06-11
- Neoadjuvant Dalpiciclib + AI → SHR-A1811 for HR+/HER2-Low Breast CancerNot yet recruiting · Phase 2 · Interventional · 20 enrolled · Tang-Du HospitalNCT07618923updated 2026-06-11
- Tamoxifen Citrate, Letrozole, Anastrozole, or Exemestane With or Without Chemotherapy in Treating Patients With Invasive RxPONDER Breast CancerActive not recruiting · Phase 3 · Interventional · 5,018 enrolled · National Cancer Institute (NCI)NCT01272037updated 2026-06-11
- Roll-over Study to Allow Continued Access to RibociclibActive not recruiting · Phase 4 · Interventional · 134 enrolled · Novartis PharmaceuticalsNCT05161195updated 2026-06-11
- Reversing InGuinal Hernia Trial: The Evaluation of Sex Hormones to Reverse Inguinal Hernias in MalesNot yet recruiting · Phase 1 · Interventional · 30 enrolled · Northwestern UniversityNCT07604272updated 2026-06-11
- A Study Evaluating the Efficacy and Safety of Adjuvant Giredestrant Compared With Physician's Choice of Adjuvant Endocrine Monotherapy in Participants With Estrogen Receptor-Positive, HER2-Negative Early Breast Cancer (lidERA Breast Cancer)Active not recruiting · Phase 3 · Interventional · 4,170 enrolled · Hoffmann-La RocheNCT04961996updated 2026-06-10
- Phase IIIb Study of Ribociclib + ET in Early Breast CancerRecruiting · Phase 3 · Interventional · 1,400 enrolled · Novartis PharmaceuticalsNCT05827081updated 2026-06-09
- Testing Low Dose Tamoxifen for Invasive Breast Cancer, LoTam TrialSuspended · Phase 3 · Interventional · 1,556 enrolled · Alliance for Clinical Trials in OncologyNCT06671912updated 2026-06-08
- Fulvestrant and/or Anastrozole in Treating Postmenopausal Patients With Stage II-III Breast Cancer Undergoing SurgeryActive not recruiting · Phase 3 · Interventional · 1,473 enrolled · Alliance for Clinical Trials in OncologyNCT01953588updated 2026-06-05
Frequently asked questions
- How does Anastrozole work?
- The growth of many cancers of the breast is stimulated or maintained by estrogens. In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol.
- What is Anastrozole used for?
- According to FDA labeling, Anastrozole carries indications including: Anastrozole is an aromatase inhibitor indicated for: Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer ( 1.1 ) First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer ( 1.2 ) Treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy. Patients with ER-negative disease and patients who did not respond to previous tamoxifen therapy rarely responded to anastrozole ( 1.3 ) 1.1 Adjuvant Treatment Anastrozole tablets are indicated for adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
- What class of drug is Anastrozole?
- Anastrozole is classified as Aromatase inhibitors, Aromatase Inhibitor, Aromatase Inhibitors, Enzyme Inhibitors, Decreased Ovarian Estrogen Secretion.
- What are the brand names for Anastrozole?
- Anastrozole is marketed under brand names including Arimidex.
- What are the contraindications for Anastrozole?
- Anastrozole labeling lists contraindications including: Hypersensitivity Anastrozole is contraindicated in any patient who has shown a hypersensitivity reaction to the drug or to any of the excipients. Observed reactions include anaphylaxis, angioedema, and urticaria [see Adverse Reactions ( 6.2 )].. Always consult the full prescribing information and a clinician.
anastrozole is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.