Arimidexanastrozole
According to the FDA label: ARIMIDEX 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.
35,752 adverse event reports submitted to the FDA (2003–2026)
Top Reported Adverse Events
The most frequently reported events in association with Arimidex in the FAERS database. These are events reported by patients taking this medication, not necessarily caused by it. A single report may include multiple events.
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Fatigue 3,340 reports
Extreme tiredness or lack of energy that does not improve with rest.
Full definition in the glossary → See all drugs reporting this event →Arthralgia 3,189 reports
Nausea 2,708 reports
The feeling of sickness in your stomach that often comes before vomiting.
Full definition in the glossary → See all drugs reporting this event →Alopecia 2,557 reports
Diarrhoea 2,328 reports
Loose or watery bowel movements, often frequent. Also spelled diarrhea in American English.
Full definition in the glossary → See all drugs reporting this event →Pain 1,802 reports
A general report of physical discomfort, used when no more specific location is given.
Full definition in the glossary →Headache 1,776 reports
Pain in the head or upper neck.
Full definition in the glossary → See all drugs reporting this event →Asthenia 1,592 reports
Physical weakness or lack of strength.
Full definition in the glossary →Dyspnoea 1,563 reports
Shortness of breath or difficulty breathing. Also spelled dyspnea in American English.
Full definition in the glossary → See all drugs reporting this event →Dizziness 1,499 reports
A feeling of being lightheaded, unsteady, or like the room is spinning.
Full definition in the glossary → See all drugs reporting this event →Hot Flush 1,413 reports
A sudden feeling of heat, often in the face and upper body, sometimes with sweating. Often called a hot flash in American English.
Full definition in the glossary → See all drugs reporting this event →Pain in Extremity 1,390 reports
Pain in an arm or leg.
Full definition in the glossary →Malignant Neoplasm Progression 1,354 reports
A report that a cancer grew or spread. This describes the course of the illness, not necessarily an effect of the drug. Malignant neoplasm is the medical term for a cancerous growth.
Full definition in the glossary →Vomiting 1,300 reports
Throwing up the contents of the stomach.
Full definition in the glossary → See all drugs reporting this event →Malaise 1,298 reports
A general feeling of being unwell or uncomfortable, without a specific symptom.
Full definition in the glossary →
Ranked by frequency of reports, not severity. The most-reported event is not necessarily the most dangerous or the most common in patients taking this drug.
Who Is Reporting
Demographics of patients in FAERS reports that included this information. Not all reports include patient demographics.
By Sex
View reporter sex data as a table
| Sex | Reports |
|---|---|
| Female | 31,670 |
| Male | 1,632 |
| Unknown | 136 |
By Age Group
View age group data as a table
| Age group | Reports |
|---|---|
| 0-17 | 316 |
| 18-34 | 326 |
| 35-49 | 2,120 |
| 50-64 | 8,973 |
| 65-74 | 6,941 |
| 75+ | 5,209 |
This shows who filed reports, reflecting who takes this drug and who tends to report, not who is at greatest risk.
Reported Outcomes
Outcomes recorded in FAERS reports that included Arimidex. A single report may involve multiple reactions, each with a different outcome. These categories are defined by FDA reporting guidelines, not by PillSignal.
View outcome data as a table
| Outcome | Reports |
|---|---|
| Other Serious | 18,002 |
| Non-Serious | 11,426 |
| Hospitalization | 7,766 |
| Death | 2,400 |
| Disability | 1,197 |
| Life-Threatening | 1,094 |
Serious outcomes are far more likely to be reported than mild ones, so this overstates how often outcomes are serious. A recorded death does not mean the drug caused it.
Report Volume Over Time
Number of FAERS reports received per quarter for Arimidex. Changes in volume may reflect shifts in prescribing rates, media attention, or reporting behavior, not changes in the medication's safety profile.
View report trend as a table
| Year | Reports |
|---|---|
| 2003 | 1 |
| 2004 | 277 |
| 2005 | 384 |
| 2006 | 548 |
| 2007 | 1,231 |
| 2008 | 1,491 |
| 2009 | 1,838 |
| 2010 | 1,308 |
| 2011 | 1,385 |
| 2012 | 1,449 |
| 2013 | 965 |
| 2014 | 994 |
| 2015 | 1,268 |
| 2016 | 1,609 |
| 2017 | 1,936 |
| 2018 | 2,254 |
| 2019 | 2,548 |
| 2020 | 2,233 |
| 2021 | 2,081 |
| 2022 | 2,315 |
| 2023 | 2,607 |
| 2024 | 2,272 |
| 2025 | 2,248 |
| 2026 (partial) | 510 |
The steep increase around 2004 reflects the FDA's move to electronic submission, not a change in this drug's safety. Trends track reporting volume, not risk.
Medications commonly reported with Arimidex
In FDA adverse event reports that mention Arimidex, these medications appeared most often in the same report.
- Palbociclib (4,196 reports)
- Ergocalciferol (2,993 reports)
- Aspirin (2,682 reports)
- Letrozole (2,527 reports)
- Fulvestrant (2,252 reports)
This reflects co-occurrence in submitted reports, not evidence of drug interaction or combined risk. People often report several medications taken for the same condition or for unrelated reasons. Talk to a doctor or pharmacist about your specific medications.
Related Drugs
Other medications with similar adverse event profiles in FDA FAERS reports.
Data Source
This data is sourced from the FDA's Adverse Event Monitoring System (AEMS), formerly FAERS, via the OpenFDA API. PillSignal is not affiliated with the FDA.
View this data on the FDA website →Data last updated: June 2026