Prescription medication · Aromatase Inhibitor
anastrozole
Also sold as Arimidex. Anastrozole is used to treat breast cancer in women who have gone through menopause.
Data updated 2026-05-15
- 35,161
- FDA reportsModerately reported
- 2
- InteractionsFew interactions
- 99% less
- Generic vs brandHuge savings
- $51.78
- Brand price (NADAC)
What the data shows
anastrozole (Arimidex) is a prescription Aromatase Inhibitor, reported at a middle-of-the-pack volume (35,161 FDA reports), whose generic costs a fraction of the brand (about 99% less).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
anastrozole (Arimidex) is a prescription Aromatase Inhibitor. Anastrozole is used to treat breast cancer in women who have gone through menopause.
Anastrozole is a medicine used to treat breast cancer in women after menopause. It lowers estrogen levels in the body, which can help stop the growth of cancer cells.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$51.78/unit
Generic Price
$0.14/unit
Generic Savings
99%
Generic Available
Yes (6 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
NADAC price trail: ANASTROZOLE 1 MG TABLET
Same CMS presentation as the headline generic unit price above (2 effective dates). Adjacent % compares consecutive NADAC releases for this description only, not a patient out-of-pocket quote. Latest step: +5.8% vs prior release.
| Effective | NADAC / unit | vs prior | NDCs |
|---|---|---|---|
| July 17, 2024 | $0.1293/EA | - | 2 |
| December 18, 2024 | $0.1368/EA | +5.8% | 22 |
What it does
Anastrozole is used to treat breast cancer in women who have gone through menopause.
Common side effects
Hot flashes, Weakness or fatigue, Arthritis
Key warnings
Anastrozole may cause heart problems in women who already have heart disease.
The sections below are summarized in plain English from anastrozole's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Anastrozole belongs to a class of drugs called aromatase inhibitors. It works by blocking an enzyme called aromatase, which the body uses to make estrogen. By lowering estrogen levels, anastrozole can slow or stop the growth of breast cancer cells that need estrogen to grow.
Side Effects (from patient reports)
Based on 35,161 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for anastrozole, by number of reports
- Fatigue
Fatigue
3,256 reports
- Arthralgia
Arthralgia
3,158 reports
- Nausea
Nausea
2,648 reports
- Alopecia
Alopecia
2,537 reports
- Diarrhoea
Diarrhoea
2,267 reports
- Pain
Pain
1,773 reports
- Headache
Headache
1,741 reports
- Asthenia
Asthenia
1,569 reports
- Dyspnoea
Dyspnoea
1,530 reports
- Dizziness
Dizziness
1,468 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for anastrozole each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where anastrozole sits
anastrozole has more FDA adverse-event reports than 67% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is anastrozole; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 35,161 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2003–2025.
Total Reports
35,161
Reports Mentioning Death
2,383
6.8% of reports — not proof of cause
Hospitalization Reports
7,649
Top Indication
Breast Cancer
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | FATIGUE | 3,256 |
| 2 | ARTHRALGIA | 3,158 |
| 3 | NAUSEA | 2,648 |
| 4 | ALOPECIA | 2,537 |
| 5 | DIARRHOEA | 2,267 |
| 6 | PAIN | 1,773 |
| 7 | HEADACHE | 1,741 |
| 8 | ASTHENIA | 1,569 |
| 9 | DYSPNOEA | 1,530 |
| 10 | DIZZINESS | 1,468 |
| 11 | HOT FLUSH | 1,402 |
| 12 | PAIN IN EXTREMITY | 1,368 |
| 13 | MALIGNANT NEOPLASM PROGRESSION | 1,313 |
| 14 | MALAISE | 1,278 |
| 15 | VOMITING | 1,270 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Anastrozole may cause heart problems in women who already have heart disease. It can also weaken your bones, so your doctor may want to check your bone density. This medicine can harm an unborn baby, so use birth control while taking it and for 3 weeks after your last dose.
Known Drug Interactions
7 DRUG INTERACTIONS Tamoxifen: Do not use in combination with anastrozole. No additional benefit seen over tamoxifen monotherapy ( 7.1 , 14.1 ). 7.1 Tamoxifen Co-administration of anastrozole and tamoxifen in breast cancer patients reduced anastrozole plasma concentration by 27%.
Mechanism: Tamoxifen lowers the amount of anastrozole in your blood, which may make the treatment less effective against cancer. Research also shows that taking both drugs together provides no extra benefit compared to taking just one.
7.3 Warfarin In a study conducted in 16 male volunteers, anastrozole did not alter the exposure (as measured by C max and AUC), and anticoagulant activity (as measured by prothrombin time, activated partial thromboplastin time, and thrombin time) of both R- and S-warfarin.
Mechanism: Research shows that this medicine does not interfere with how the blood thinner works or how much of it stays in your body.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
Can I take anastrozole if I am still having periods?
How long will I need to take anastrozole?
Can anastrozole cure my breast cancer?
Will anastrozole cause weight gain?
Can I drink alcohol while taking anastrozole?
What should I do if I have severe side effects?
Can I take other medicines with anastrozole?
Will anastrozole cause hair loss?
Does anastrozole affect my cholesterol?
What if I have liver or kidney problems?
What are the common side effects of anastrozole?
Does anastrozole interact with other medications?
What drug class is anastrozole?
Is there a generic version of anastrozole?
What pregnancy or breastfeeding source fields are listed for anastrozole?
Related Medications in Aromatase Inhibitor
Other drugs grouped near anastrozole - same-class peers and common alternatives.
abiraterone
Zytiga
Abiraterone (Zytiga) is a medicine used with prednisone to treat prostate cancer that has spread.
Compare with anastrozole →
bazedoxifene/conjugated estrogens
Duavee
Duavee is a combination medicine containing estrogen and a drug that blocks estrogen in some parts of the body.
Compare with anastrozole →
cabergoline
Dostinex
Cabergoline is a medicine that helps lower the amount of prolactin in your body.
Compare with anastrozole →
clomiphene
Clomid, Serophene
Clomiphene citrate is a medicine that helps women ovulate.
Compare with anastrozole →
conjugated estrogens
Premarin
Premarin Intravenous is an injectable medicine that contains estrogen hormones.
Compare with anastrozole →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for anastrozole: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 35,161.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 6.78%.
- buspirone Δ 0.01 pts · 10,228 reports · Azapirone Anxiolytic 6.79%death share
- ziprasidone Δ 0.02 pts · 17,328 reports · Atypical Antipsychotic 6.76%death share
- oxcarbazepine Δ 0.05 pts · 31,347 reports · Anticonvulsant 6.73%death share
- omadacycline Δ 0.07 pts · 1,476 reports · Tetracycline Antibiotic 6.84%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for anastrozole
The FDA label for anastrozole (sold under brand names such as Arimidex) classifies it as a prescription-only medication in the Aromatase Inhibitor class. Anastrozole is used to treat breast cancer in women who have gone through menopause. Official labeling lists 20 commonly reported side effects, including Hot flashes, Weakness or fatigue, Arthritis.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 35,161 voluntary reports. The database also lists 2 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.14 versus $51.78 for the brand - a 99% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: February 11, 2026
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages