Pharmacologic class (EPC) · 6 drug pages

Complement inhibitor: adverse event reports filed with FDA

69,459 reports list a drug in this class as a suspect or interacting product, 2007–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

69,459
reports across the class: 0.3% of all reports; 5,986
reports, 12 months to June 2026: 5,776 in the 12 months before; 58.7%
marked serious by the reporter: 57.4% across all reports; 6
drugs with a page: brand and generic names counted separately

Complement inhibitor is a pharmacologic class (an FDA Established Pharmacologic Class) with 6 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 69,459 adverse event reports received by FDA, 0.3% of the database, from May 2007 to June 2026.

5,986 reports arrived in the 12 months to June 2026, close to the 5,776 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 58.7% of the class's reports are marked serious, 9.7% record death among the outcomes and 26.2% record hospitalisation, as reported.

Across the class the reactions recorded most often are fatigue (11.3%), off label use (7.5%) and haemoglobin decreased (6.5%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
SolirisEculizumab	brand	52,768	1,330	57.8%	Fatigue
UltomirisRavulizumab	brand	11,279	1,816	47.8%	Fatigue
Eculizumab	generic	2,072	817	97.2%	Off label use
Ravulizumab	generic	1,919	1,712	98.9%	Fatigue
Pegcetacoplan	generic	768	146	71.4%	Fatigue
SyfovrePegcetacoplan	brand	653	165	66.6%	Visual impairment

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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Fatiguetiredness11.3%7,857
Off label useused for a purpose or in a way not on the label7.5%5,212
Haemoglobin decreasedlow haemoglobin6.5%4,522
Headachehead pain6.3%4,373
Deaththe patient died; cause not stated by this term4.9%3,418
Astheniaweakness or lack of energy4.3%2,967
Pyrexiafever4%2,797
Dyspnoeashortness of breath4%2,758
Drug ineffectivethe medicine did not work as expected3.8%2,620
Nauseafeeling sick3.4%2,383
Haemolysis3.3%2,325
Malaisegeneral feeling of being unwell3.3%2,299
Platelet count decreasedlow platelet count3%2,062
Painpain, site not specified2.8%1,948
Back painback pain2.7%1,841
Blood lactate dehydrogenase increased2.6%1,787
Diarrhoealoose or frequent stools2.5%1,726
Abdominal painstomach or belly pain2.5%1,711
Vomitingbeing sick2.4%1,701
Condition aggravatedthe condition being treated got worse2.4%1,649
Nasopharyngitisa cold2.4%1,639
Pneumonialung infection2.1%1,448
Arthralgiajoint pain2%1,420
Hospitalisationadmission to hospital2%1,417
Dizzinesslight-headedness or unsteadiness2%1,401

Solid bar: share of all class reports. Hollow bar: the median share across the 6 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death9.7%6,749

Life-threatening1.6%1,142

Hospitalisation (initial or prolonged)26.2%18,209

Disability0.5%354

Congenital anomaly0%31

Other serious46.4%32,244

Not serious41.3%28,677

Patient age

Under 20.7%519

2 to 111.6%1,146

12 to 171.1%733

18 to 448.8%6,083

45 to 646.5%4,547

65 to 743.7%2,547

75 and over3.1%2,187

Age not given74.4%51,697

Who reported

Physician16.9%11,716

Pharmacist2.2%1,560

Other health professional10%6,933

Lawyer0%2

Consumer or non-health professional68.3%47,451

Not given2.6%1,797

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Complement inhibitor reports

Which drugs are in the Complement inhibitor class on this site?

Soliris, Ultomiris, Eculizumab, Ravulizumab, Pegcetacoplan and Syfovre. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

69,459 reports through June 2026, 5,986 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

fatigue (11.3%), off label use (7.5%), haemoglobin decreased (6.5%), headache (6.3%) and death (4.9%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. 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 class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.