Reported Reactions

Drugs › Complement inhibitor

Generic name

Eculizumab: adverse event reports filed with FDA

2,072 reports list it as a suspect or interacting product, 2009–2026. Class: Complement inhibitor.

2,072
reports as suspect product
0% of all reports · about 121 a year
817
reports, 12 months to June 2026
200 in the 12 months before
97.2%
marked serious by the reporter
58.7% across the class
16.7%
record death among outcomes, as reported
346 reports · not verified by FDA

2,072 adverse event reports received by FDA list eculizumab, a generic name as a suspect or interacting product, from May 2009 to June 2026. A further 697 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, 817 reports listed it, up 309% from 200 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 121 reports a year and 0% of the 20,646,523 reports in the database, and 3% of the reports for the complement inhibitor class. How many people take it is not in the data, so a count is not a rate of occurrence.

Reporters most often recorded off label use (17.3%), drug ineffective (9%) and death (5.9%). A report can list several reactions, so shares add to more than 100%; 575 different terms appear across these reports. Off label use is recorded in 17.3% of these reports, a larger share than in the median complement inhibitor drug (6.1%).

97.2% of the reports are marked serious by the reporter (58.7% across the class); 16.7% record death among the outcomes and 49.1% record hospitalisation, as reported. 46% of the reports came from other health professionals, and the largest patient age group is 18 to 44 (26.2%). 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

0155309Jul 2021: 14Aug 2021: 8Sep 2021: 11Oct 2021: 4Nov 2021: 12Dec 2021: 172022Jan 2022: 6Feb 2022: 8Mar 2022: 1Apr 2022: 5May 2022: 2Jun 2022: 7Jul 2022: 8Aug 2022: 19Sep 2022: 6Oct 2022: 6Nov 2022: 1Dec 2022: 82023Jan 2023: 2Feb 2023: 9Mar 2023: 6Apr 2023: 4May 2023: 7Jun 2023: 15Jul 2023: 3Aug 2023: 3Sep 2023: 3Oct 2023: 7Nov 2023: 2Dec 2023: 72024Jan 2024: 4Feb 2024: 7Mar 2024: 14Apr 2024: 9May 2024: 10Jun 2024: 7Jul 2024: 19Aug 2024: 8Sep 2024: 11Oct 2024: 31Nov 2024: 15Dec 2024: 292025Jan 2025: 20Feb 2025: 19Mar 2025: 15Apr 2025: 7May 2025: 17Jun 2025: 9Jul 2025: 19Aug 2025: 32Sep 2025: 29Oct 2025: 32Nov 2025: 22Dec 2025: 742026Jan 2026: 35Feb 2026: 40Mar 2026: 69Apr 2026: 67May 2026: 309Jun 2026: 89

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

03056092009: 620092010: 52011: 720112012: 102013: 9020132014: 1042015: 14120152016: 902017: 8120172018: 662019: 6620192020: 722021: 12120212022: 772023: 6820232024: 1642025: 29520252026: 609

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Eculizumab reports recording the termmedian drug in complement inhibitor

  1. Off label useused for a purpose or in a way not on the label17.3%359
  2. Drug ineffectivethe medicine did not work as expected9%186
  3. Deaththe patient died; cause not stated by this term5.9%123
  4. Renal impairmentreduced kidney function4.2%88
  5. Maternal exposure during pregnancythe mother took the medicine during pregnancy3.4%71
  6. Covid-19COVID-19 infection2.8%59
  7. Pyrexiafever2.8%58
  8. Pneumonialung infection2.7%55
  9. Infectionan infection, type not specified2.6%54
  10. Condition aggravatedthe condition being treated got worse2.6%53
  11. Acute kidney injurysudden loss of kidney function2.3%48
  12. Fatiguetiredness2.2%46
  13. Hypertensionhigh blood pressure2.2%45
  14. Foetal exposure during pregnancythe unborn baby was exposed to the medicine2.1%44
  15. Premature babya baby born early2.1%44
  16. Exposure during pregnancythe medicine was taken during pregnancy2%42
  17. Sepsisa severe body-wide response to infection1.9%40
  18. Headachehead pain1.9%39
  19. Multiple organ dysfunction syndromeseveral organs failing1.9%39
  20. Urinary tract infectionbladder or urinary infection1.9%39
  21. End stage renal diseasekidney failure needing dialysis or transplant1.8%38
  22. Anaemialow red blood cells1.6%34
  23. Dyspnoeashortness of breath1.6%33

Top 30 of 575 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 6 drugs in the complement inhibitor 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

Death16.7%346
Life-threatening8.3%171
Hospitalisation (initial or prolonged)49.1%1,017
Disability1.2%24
Congenital anomaly0%0
Other serious62.2%1,289
Not serious2.8%59

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 69,459 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 21.7%36
2 to 119.4%195
12 to 174.6%96
18 to 4426.2%543
45 to 6414%291
65 to 746.7%138
75 and over2.4%50
Age not given34.9%723

Patient sex

Female51.2%1,061
Male30.1%623
Not given18.7%388

Who reported

Physician31.6%655
Pharmacist2.2%45
Other health professional46%953
Lawyer0%0
Consumer or non-health professional19.5%404
Not given0.7%15

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 47.1% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Haemolytic uraemic syndrome30214.6%
Atypical haemolytic uraemic syndrome24211.7%
Myasthenia gravis1879%
Paroxysmal nocturnal haemoglobinuria1607.7%
Thrombotic microangiopathy1577.6%
Neuromyelitis optica spectrum disorder532.6%

The indication field is filled in by the reporter and is often blank; shares are of all 2,072 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Eculizumab reports
Prednisone36917.8%
Mycophenolate mofetil31415.2%
Tacrolimus29514.2%
Rituximab27313.2%
Methylprednisolone2009.7%
Azathioprine1718.3%
Cyclophosphamide1396.7%
Prednisolone1396.7%
Aspirin904.3%
Amlodipine834%

Other products listed in reports where Eculizumab 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

MeasureEculizumabComplement inhibitorAll reports
Reports as suspect product2,07269,45920,646,523
Share of that pool—3%0%
Reports, latest 12 months817—1,332,454
Marked serious97.2%58.7%57.4%
Death recorded among outcomes, per 1,000 reports1679791
Hospitalisation recorded, per 1,000 reports491262213
Consumer-filed share19.5%68.3%45.8%
Top term, share of reportsOff label use 17.3%median 6.1%4.1%

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 complement inhibitor class

DrugName typeReportsLatest 12 monthsMarked serious
Solirisbrand52,7681,33057.8%
Ultomirisbrand11,2791,81647.8%
Ravulizumabgeneric1,9191,71298.9%
Pegcetacoplangeneric76814671.4%
Syfovrebrand65316566.6%

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 Eculizumab reports

How many adverse event reports has FDA received for Eculizumab?

2,072 reports list Eculizumab as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 817 of them arrived in the latest 12 months. Another 697 list it only as a concomitant medication.

What reactions are recorded in Eculizumab reports?

off label use (17.3%), drug ineffective (9%), death (5.9%), thrombotic microangiopathy (5%) and renal impairment (4.2%). 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 Eculizumab was responsible.

How serious are the reports?

97.2% are marked serious by the reporter. Among the outcomes recorded, 16.7% of reports include death and 49.1% 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 (46%), physician (31.6%) and consumer or non-health professional (19.5%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Eculizumab rising?

817 reports in the 12 months to June 2026, up 309% from 200 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 Eculizumab 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 Eculizumab?

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 Eculizumab as a suspect or interacting product; reports listing it only as a concomitant medication (697) 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.