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Anastrozole Side Effects

The most commonly reported side effects of anastrozole include fatigue, nausea, and alopecia, based on 36,214 FDA adverse event reports from 2004 to 2025. 2.9% of reports found the drug to be ineffective.

Anastrozole side effects

Percentages show how often each reaction appears relative to total reports for anastrozole.

1
Fatigue7.9%2,866
2
Nausea6.3%2,276
3
Alopecia6.2%2,257
4
Arthralgia6.0%2,167
5
Diarrhoea5.8%2,106
6
Pain4.0%1,450
7
Headache3.9%1,421
8
Dyspnoea3.8%1,360
9
Malignant Neoplasm Progression3.6%1,314
10
Asthenia3.6%1,293
11
Dizziness3.4%1,214
12
Off Label Use3.2%1,154
13
Vomiting3.2%1,149
14
Arthralgia3.1%1,117
15
Malaise3.0%1,103

These are voluntary reports and do not establish that anastrozole caused these reactions.

Report severity

68.4%Serious24,779 reports
22.0%Hospitalizations7,954 reports
6.8%Fatal2,460 reports

Seriousness is determined by the reporter, not by OpenClaim.

Anastrozole drug interactions

Other drugs that appear in adverse event reports alongside anastrozole. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Palbociclib10.5%3,811
2
Docetaxel7.2%2,625
3
Ribociclib5.3%1,927
4
Letrozole4.9%1,758
5
Trastuzumab4.7%1,716
6
Tamoxifen-citrate4.5%1,632
7
Fulvestrant4.4%1,596
8
Zoledronic-acid4.2%1,532
9
Exemestane3.7%1,326
10
Capecitabine2.6%959
11
Denosumab2.6%954
12
Paclitaxel2.6%946
13
Cyclophosphamide2.2%813
14
Pertuzumab2.1%771
15
Abemaciclib2.0%711

Taken alongside

1
Ergocalciferol9.4%3,398
2
Levothyroxine-sodium9.0%3,253
3
Acetaminophen8.3%3,005
4
Aspirin8.1%2,922
5
Calcium6.6%2,399
6
Atorvastatin-calcium5.8%2,117
7
Omeprazole5.8%2,112
8
Amlodipine5.3%1,935
9
Metoprolol4.9%1,770
10
Metformin4.8%1,752
11
Lisinopril4.8%1,749
12
Gabapentin4.7%1,690
13
Furosemide4.6%1,675
14
Hydrochlorothiazide4.4%1,602
15
Ondansetron4.0%1,432

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports anastrozole side effects

88.7% of anastrozole adverse event reports involve female patients and 4.5% involve male patients. The largest age group is elderly at 51%. These figures reflect who reports side effects, not underlying risk.

Sex

Female88.7%
Male4.5%
Unknown6.7%

Age group

< 2<0.1%
2–110.3%
12–170.6%
18–6448.0%
65+51.1%

What is anastrozole used for

Conditions and purposes for which patients were taking anastrozole when the adverse event was reported.

AcromegalyAddison^s DiseaseAdenocarcinomaAdenoma BenignAdjuvant TherapyAdrenogenital SyndromeAdverse Drug ReactionAdverse EventAdverse ReactionAlbright^s DiseaseAlopeciaAnabolic DietAnaemiaAndrogen DeficiencyAndrogen Replacement Therapy

Showing 15 of 532 indications

Anastrozole brand names and reporting trend

Anastrozole is sold under the brand name Arimidex.

Brand names

Arimidex22,736

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking anastrozole with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.