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Sulfasalazine Side Effects

The most commonly reported side effects of sulfasalazine include rheumatoid arthritis, pain, and drug intolerance, based on 78,381 FDA adverse event reports from 2004 to 2025. 36.9% of reports found the drug to be ineffective.

Sulfasalazine side effects

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

1
Drug Ineffective36.9%28,926
2
Rheumatoid Arthritis24.2%18,989
3
Pain19.9%15,597
4
Drug Intolerance17.3%13,539
5
Arthralgia16.5%12,957
6
Fatigue16.4%12,891
7
Joint Swelling15.9%12,439
8
Off Label Use13.8%10,814
9
Rash13.4%10,488
10
Abdominal Discomfort12.5%9,830
11
Contraindicated Product Administered12.1%9,462
12
Condition Aggravated11.9%9,298
13
Alopecia11.8%9,270
14
Arthropathy11.5%8,999
15
Synovitis11.4%8,961

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

Report severity

83.1%Serious65,169 reports
27.2%Hospitalizations21,323 reports
8.6%Fatal6,727 reports

Seriousness is determined by the reporter, not by OpenClaim.

Sulfasalazine drug interactions

Other drugs that appear in adverse event reports alongside sulfasalazine. 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
Methotrexate46.3%36,317
2
Etanercept40.2%31,535
3
Adalimumab39.1%30,622
4
Leflunomide33.5%26,271
5
Hydroxychloroquine-sulfate32.9%25,773
6
Abatacept29.7%23,263
7
Tocilizumab27.3%21,411
8
Infliximab27.1%21,226
9
Rituximab26.2%20,536
10
Certolizumab-pegol19.3%15,155
11
Golimumab19.2%15,050
12
Prednisone18.6%14,599
13
Tofacitinib17.5%13,717
14
Diclofenac14.0%10,993
15
Folic-acid13.8%10,844

Taken alongside

1
Prednisone18.5%14,526
2
Methotrexate16.2%12,693
3
Hydroxychloroquine-sulfate14.6%11,451
4
Acetaminophen13.6%10,636
5
Folic-acid13.0%10,225
6
Tofacitinib11.9%9,323
7
Pantoprazole-sodium9.0%7,067
8
Ergocalciferol8.8%6,893
9
Leflunomide8.2%6,436
10
Ibuprofen8.2%6,417
11
Naproxen6.7%5,213
12
Celecoxib6.2%4,853
13
Levothyroxine-sodium6.1%4,745
14
Diclofenac5.5%4,304
15
Calcium4.9%3,860

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 sulfasalazine side effects

68.3% of sulfasalazine adverse event reports involve female patients and 21.0% involve male patients. The largest age group is adult at 71%. These figures reflect who reports side effects, not underlying risk.

Sex

Female68.3%
Male21.0%
Unknown10.8%

Age group

< 20.5%
2–110.7%
12–170.9%
18–6471.4%
65+26.5%

What is sulfasalazine used for

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

Abdominal DiscomfortAbdominal PainAbdominal Pain UpperAcneAcne FulminansAdverse Drug ReactionAdverse ReactionAlopecia AreataAmnestic DisorderAnalgesic Intervention Supportive TherapyAnaplastic AstrocytomaAngiocentric LymphomaAnkylosing SpondylitisAnnular Elastolytic Giant Cell GranulomaAnti-cyclic Citrullinated Peptide Antibody

Showing 15 of 524 indications

Sulfasalazine brand names and reporting trend

Sulfasalazine is sold under the brand name Azulfidine.

Brand names

Azulfidine152,213

Quarterly reports (20042025)

20052010201520202025

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

Taking sulfasalazine with another medication?

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