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Methotrexate Side Effects

The most commonly reported side effects of methotrexate include rheumatoid arthritis, off label use, and arthralgia, based on 495,536 FDA adverse event reports from 2004 to 2025. 18.5% of reports found the drug to be ineffective.

Methotrexate side effects

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

1
Drug Ineffective18.5%91,669
2
Rheumatoid Arthritis8.2%40,479
3
Off Label Use7.8%38,858
4
Arthralgia7.7%38,079
5
Pain7.7%38,016
6
Fatigue6.3%30,982
7
Nausea5.4%26,837
8
Drug Intolerance5.0%24,974
9
Joint Swelling4.9%24,121
10
Condition Aggravated4.6%22,643
11
Headache4.2%21,044
12
Rash4.2%20,980
13
Drug Hypersensitivity4.0%19,614
14
Diarrhoea3.9%19,185
15
Pain In Extremity3.8%18,634

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

Report severity

73.0%Serious361,736 reports
27.1%Hospitalizations134,462 reports
7.5%Fatal37,250 reports

Seriousness is determined by the reporter, not by OpenClaim.

Methotrexate drug interactions

Other drugs that appear in adverse event reports alongside methotrexate. 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
Etanercept23.1%114,270
2
Adalimumab22.2%109,881
3
Infliximab11.5%57,109
4
Rituximab10.5%52,242
5
Leflunomide9.7%48,286
6
Abatacept9.6%47,506
7
Tocilizumab9.3%45,961
8
Hydroxychloroquine-sulfate8.8%43,681
9
Prednisone8.1%40,089
10
Sulfasalazine6.4%31,604
11
Tofacitinib6.2%30,875
12
Certolizumab-pegol5.6%27,898
13
Vincristine-sulfate5.5%27,378
14
Golimumab5.4%26,603
15
Cyclophosphamide4.8%23,895

Taken alongside

1
Folic-acid19.0%93,969
2
Prednisone13.4%66,313
3
Acetaminophen7.9%39,111
4
Hydroxychloroquine-sulfate7.2%35,441
5
Ergocalciferol5.5%27,318
6
Levothyroxine-sodium4.4%21,908
7
Omeprazole4.2%20,620
8
Tofacitinib4.0%19,880
9
Sulfasalazine4.0%19,834
10
Pantoprazole-sodium3.9%19,178
11
Aspirin3.5%17,539
12
Calcium3.4%17,058
13
Ibuprofen3.4%16,980
14
Leflunomide3.3%16,555
15
Prednisolone3.1%15,609

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 methotrexate side effects

64.1% of methotrexate adverse event reports involve female patients and 26.1% involve male patients. The largest age group is adult at 61%. These figures reflect who reports side effects, not underlying risk.

Sex

Female64.1%
Male26.1%
Unknown9.8%

Age group

< 20.8%
2–115.2%
12–173.9%
18–6461.3%
65+28.9%

What is methotrexate used for

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

Abdominal DiscomfortAbdominal PainAbdominal Pain UpperAbortionAbortion InducedAbortion Of Ectopic PregnancyAccidental ExposureAccidental Exposure To ProductAccidental OverdoseAcneAcquired Amegakaryocytic ThrombocytopeniaAcquired Epidermolysis BullosaAcquired Gene MutationAcquired Immunodeficiency SyndromeAcrodermatitis

Showing 15 of 3,072 indications

Methotrexate brand names and reporting trend

Methotrexate is sold under brand names including Otrexup Pfs, Folex.

Brand names

Otrexup Pfs611,286
Folex104,265

Quarterly reports (20042025)

20052010201520202025

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

Taking methotrexate with another medication?

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