Reported Reactions

Drugs › Antirheumatic agent

Brand name · Leflunomide

Arava: adverse event reports filed with FDA

34,203 reports list it as a suspect or interacting product, 2004–2026. Class: Antirheumatic agent. Also reported as Arava /01414801/.

34,203
reports as suspect product
0.2% of all reports · about 1,521 a year
1,424
reports, 12 months to June 2026
2,110 in the 12 months before
89.8%
marked serious by the reporter
92.1% across the class
12.5%
record death among outcomes, as reported
4,262 reports · not verified by FDA

34,203 adverse event reports received by FDA list the brand name Arava (leflunomide) as a suspect or interacting product, from January 2004 to June 2026. A further 18,730 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 1,424 reports listed it, down 33% from 2,110 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 1,521 reports a year and 0.2% of the 20,646,523 reports in the database, and 48% of the reports for the antirheumatic agent class. How many people take it is not in the data, so a count is not a rate of occurrence.

The reactions recorded most often are drug ineffective (53.3%), rheumatoid arthritis (40.9%) and pain (32.8%). A report can list several reactions, so shares add to more than 100%; 2,035 different terms appear across these reports. Drug ineffective is recorded in 53.3% of these reports, about the same share as in the median antirheumatic agent drug (51.6%).

89.8% of the reports are marked serious by the reporter (92.1% across the class); 12.5% record death among the outcomes and 27.6% record hospitalisation, as reported. 51% of the reports came from other health professionals, and the largest patient age group is 45 to 64 (23.6%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

0204408Jul 2021: 293Aug 2021: 252Sep 2021: 315Oct 2021: 308Nov 2021: 334Dec 2021: 4082022Jan 2022: 278Feb 2022: 148Mar 2022: 220Apr 2022: 250May 2022: 326Jun 2022: 351Jul 2022: 118Aug 2022: 172Sep 2022: 134Oct 2022: 173Nov 2022: 193Dec 2022: 2222023Jan 2023: 120Feb 2023: 130Mar 2023: 122Apr 2023: 101May 2023: 78Jun 2023: 71Jul 2023: 80Aug 2023: 99Sep 2023: 105Oct 2023: 113Nov 2023: 74Dec 2023: 1482024Jan 2024: 153Feb 2024: 168Mar 2024: 155Apr 2024: 166May 2024: 278Jun 2024: 222Jul 2024: 232Aug 2024: 130Sep 2024: 153Oct 2024: 240Nov 2024: 224Dec 2024: 2412025Jan 2025: 140Feb 2025: 189Mar 2025: 199Apr 2025: 87May 2025: 31Jun 2025: 244Jul 2025: 225Aug 2025: 141Sep 2025: 144Oct 2025: 80Nov 2025: 110Dec 2025: 1822026Jan 2026: 82Feb 2026: 109Mar 2026: 53Apr 2026: 93May 2026: 60Jun 2026: 145

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

02,9105,8192004: 35620042005: 4362006: 3272007: 34520072008: 3542009: 3672010: 32520102011: 3332012: 3502013: 38920132014: 4282015: 7612016: 1,39720162017: 2,4972018: 3,1122019: 4,31420192020: 5,8192021: 3,7912022: 2,58520222023: 1,2412024: 2,3622025: 1,77220252026: 542

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Arava reports recording the termmedian drug in antirheumatic agent

  1. Drug ineffectivethe medicine did not work as expected53.3%18,223
  2. Rheumatoid arthritisrheumatoid arthritis, an inflammatory joint disease40.9%13,995
  3. Painpain, site not specified32.8%11,235
  4. Drug intolerancethe medicine was not tolerated27.4%9,367
  5. Fatiguetiredness26.1%8,938
  6. Abdominal discomfortstomach discomfort26%8,905
  7. Joint swellinga swollen joint25.9%8,853
  8. Alopeciahair loss25.2%8,633
  9. Rashskin rash23.5%8,022
  10. Systemic lupus erythematosuslupus, an autoimmune disease23.2%7,949
  11. Arthralgiajoint pain23.1%7,888
  12. Pemphigus22.5%7,695
  13. Arthropathy22.2%7,607
  14. Swellingswelling21.5%7,340
  15. Glossodynia20.3%6,928
  16. Off label useused for a purpose or in a way not on the label18.7%6,401
  17. Hand deformity18.7%6,395
  18. Condition aggravatedthe condition being treated got worse18.5%6,332
  19. Synovitis18.4%6,287
  20. Treatment failurethe treatment did not work17.9%6,112
  21. Hypersensitivityan allergic-type reaction17.8%6,077
  22. Drug hypersensitivityan allergic-type reaction to a medicine16.9%5,789
  23. Wound16.1%5,507
  24. Hepatic enzyme increasedraised liver enzymes16%5,483
  25. Infusion related reactiona reaction during or soon after an infusion15.1%5,179
  26. Maternal exposure during pregnancythe mother took the medicine during pregnancy15%5,115
  27. Nauseafeeling sick14.8%5,058
  28. Peripheral swellingswelling of the arms or legs14.6%4,988

Top 30 of 2,035 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 2 drugs in the antirheumatic agent class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death12.5%4,262
Life-threatening14.7%5,016
Hospitalisation (initial or prolonged)27.6%9,455
Disability20.5%7,005
Congenital anomaly7%2,395
Other serious79.6%27,242
Not serious10.2%3,494

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 71,196 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 20.1%29
2 to 110%15
12 to 170.1%48
18 to 4420.1%6,888
45 to 6423.6%8,082
65 to 747.8%2,665
75 and over4%1,377
Age not given44.1%15,099

Patient sex

Female74.7%25,556
Male10.7%3,654
Not given14.6%4,993

Who reported

Physician25.9%8,856
Pharmacist1.2%423
Other health professional51%17,450
Lawyer0.1%29
Consumer or non-health professional20.4%6,962
Not given1.4%483

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 12.7% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Rheumatoid arthritis19,35156.6%
Psoriatic arthropathy2650.8%
Arthritis1510.4%
Foetal exposure during pregnancy1320.4%
Systemic lupus erythematosus1220.4%
Polyarthritis620.2%

The indication field is filled in by the reporter and is often blank; shares are of all 34,203 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Arava reports
Methotrexate23,84769.7%
Enbrel22,32565.3%
Humira19,53657.1%
Orencia18,46554%
Actemra17,76251.9%
Prednisone16,79349.1%
Sulfasalazine16,77449%
Remicade14,46642.3%
Cimzia13,85740.5%
Simponi13,11338.3%

Other products listed in reports where Arava is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasureAravaAntirheumatic agentAll reports
Reports as suspect product34,20371,19620,646,523
Share of that pool—48%0.2%
Reports, latest 12 months1,424—1,332,454
Marked serious89.8%92.1%57.4%
Death recorded among outcomes, per 1,000 reports12514391
Hospitalisation recorded, per 1,000 reports276308213
Consumer-filed share20.4%19.4%45.8%
Top term, share of reportsDrug ineffective 53.3%median 51.6%6.3%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the antirheumatic agent class

DrugName typeReportsLatest 12 monthsMarked serious
Leflunomidegeneric36,9932,56894.2%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Arava reports

How many adverse event reports has FDA received for Arava?

34,203 reports list Arava as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 1,424 of them arrived in the latest 12 months. Another 18,730 list it only as a concomitant medication.

What reactions are recorded in Arava reports?

drug ineffective (53.3%), rheumatoid arthritis (40.9%), pain (32.8%), drug intolerance (27.4%) and fatigue (26.1%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Arava was responsible.

How serious are the reports?

89.8% are marked serious by the reporter. Among the outcomes recorded, 12.5% of reports include death and 27.6% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

other health professional (51%), physician (25.9%) and consumer or non-health professional (20.4%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Arava rising?

1,424 reports in the 12 months to June 2026, down 33% from 2,110 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Arava was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Arava?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Arava as a suspect or interacting product; reports listing it only as a concomitant medication (18,730) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.