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Hydroxyurea Side Effects

The most commonly reported side effects of hydroxyurea include off label use, sickle cell anaemia with crisis, and fatigue, based on 20,754 FDA adverse event reports from 2004 to 2025. 3.7% of reports found the drug to be ineffective.

Hydroxyurea side effects

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

1
Off Label Use10.0%2,075
2
Sickle Cell Anaemia With Crisis6.7%1,394
3
Fatigue6.7%1,386
4
Diarrhoea6.2%1,278
5
Nausea5.5%1,149
6
Headache4.6%959
7
Anaemia4.4%911
8
Death4.4%905
9
Haemoglobin Decreased4.0%834
10
Product Dose Omission Issue3.9%810
11
Drug Ineffective3.7%777
12
Pain3.7%761
13
Pyrexia3.6%745
14
Dyspnoea3.3%693
15
Pneumonia3.2%662

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

Report severity

75.6%Serious15,686 reports
38.4%Hospitalizations7,973 reports
14.8%Fatal3,072 reports

Seriousness is determined by the reporter, not by OpenClaim.

Hydroxyurea drug interactions

Other drugs that appear in adverse event reports alongside hydroxyurea. 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
Ruxolitinib17.9%3,708
2
Voxelotor9.3%1,932
3
Imatinib-mesylate4.1%859
4
Deferasirox3.8%782
5
Venetoclax2.8%582
6
Azacitidine2.8%578
7
Dasatinib2.7%554
8
L-glutamine2.7%552
9
Cytarabine2.4%498
10
Nilotinib2.2%457
11
Methotrexate1.8%381
12
Anagrelide-hydrochloride1.6%330
13
Lenalidomide1.6%330
14
Fludarabine-phosphate1.5%317
15
Aspirin1.5%308

Taken alongside

1
Aspirin16.1%3,351
2
Folic-acid13.3%2,755
3
Allopurinol10.7%2,221
4
Acetaminophen10.3%2,138
5
Ergocalciferol8.8%1,818
6
Levothyroxine-sodium7.4%1,537
7
Furosemide7.3%1,517
8
Omeprazole7.0%1,448
9
Metoprolol6.6%1,363
10
Amlodipine6.4%1,327
11
Oxycodone5.8%1,201
12
Atorvastatin-calcium5.8%1,198
13
Pantoprazole-sodium5.1%1,056
14
Ondansetron4.7%967
15
Lisinopril4.6%945

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 hydroxyurea side effects

42.3% of hydroxyurea adverse event reports involve female patients and 38.1% involve male patients. The largest age group is elderly at 47%. These figures reflect who reports side effects, not underlying risk.

Sex

Female42.3%
Male38.1%
Unknown19.5%

Age group

< 20.7%
2–114.2%
12–175.1%
18–6442.5%
65+47.5%

What is hydroxyurea used for

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

Abdominal DistensionAbdominal PainAccidental ExposureAccidental OverdoseAcquired Immunodeficiency SyndromeAcquired Von Willebrand^s DiseaseAcral Lentiginous MelanomaAcute Chest SyndromeAcute LeukaemiaAcute Lymphocytic LeukaemiaAcute Lymphocytic Leukaemia RecurrentAcute Megakaryocytic LeukaemiaAcute Monocytic LeukaemiaAcute Myeloid LeukaemiaAcute Myeloid Leukaemia Recurrent

Showing 15 of 582 indications

Hydroxyurea brand names and reporting trend

Hydroxyurea is sold under the brand name Hydrea.

Brand names

Hydrea16,236

Quarterly reports (20042025)

20052010201520202025

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

Taking hydroxyurea with another medication?

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