Drugs › Human C1 esterase inhibitor
Generic name
Human c1-esterase inhibitor: adverse event reports filed with FDA
669 reports list it as a suspect or interacting product, 2014–2026. Class: Human C1 esterase inhibitor.
- 669
- reports as suspect product
- 0% of all reports · about 57 a year
- 54
- reports, 12 months to June 2026
- 161 in the 12 months before
- 97.9%
- marked serious by the reporter
- 84% across the class
- 10.2%
- record death among outcomes, as reported
- 68 reports · not verified by FDA
Between October 2014 and June 2026, 669 adverse event reports received by FDA list human c1-esterase inhibitor, a generic name as a suspect or interacting product. Reports that mention it only as a concomitant medication (42) are left out of every figure here.
In the 12 months to June 2026, 54 reports listed it, down 66% from 161 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 57 reports a year and 0% of the 20,646,523 reports in the database, and 20.1% of the reports for the human C1 esterase 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 hereditary angioedema (52.5%), off label use (28%) and drug ineffective (18.8%). A report can list several reactions, so shares add to more than 100%; 446 different terms appear across these reports. Hereditary angioedema is recorded in 52.5% of these reports, about the same share as in the median human C1 esterase inhibitor drug (51.6%).
97.9% of the reports are marked serious by the reporter (84% across the class); 10.2% record death among the outcomes and 50.2% record hospitalisation, as reported. 47.2% of the reports came from other health professionals, and the largest patient age group is 18 to 44 (36.2%). 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
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
2026 covers reports received through June 2026 only.
Reactions recorded in the reports
share of Human c1-esterase inhibitor reports recording the termmedian drug in human c1 esterase inhibitor
- Hereditary angioedema52.5%351
- Off label useused for a purpose or in a way not on the label28%187
- Drug ineffectivethe medicine did not work as expected18.8%126
- Product dose omission issuea dose was missed13.6%91
- Inappropriate schedule of product administrationthe product was taken at the wrong times11.2%75
- Dyspnoeashortness of breath9.7%65
- Prescribed overdose9.6%64
- Product use issuea problem in how the product was used9.4%63
- Weight increasedweight gain9.4%63
- Weight decreasedweight loss8.7%58
- Fatiguetiredness8.5%57
- Painpain, site not specified8.4%56
- Maternal exposure during pregnancythe mother took the medicine during pregnancy7.8%52
- Drug hypersensitivityan allergic-type reaction to a medicine7.6%51
- Muscle spasmsmuscle cramps7.3%49
- Astheniaweakness or lack of energy7.2%48
- Wheezingwheezing7%47
- Stressstress6.7%45
- Malaisegeneral feeling of being unwell6.6%44
- Vomitingbeing sick6.4%43
- Coughcough6.3%42
- Headachehead pain6.1%41
- Nauseafeeling sick5.8%39
- Abdominal painstomach or belly pain5.7%38
- Arthralgiajoint pain5.7%38
- Chest discomfortchest discomfort5.7%38
- Hypertensionhigh blood pressure5.7%38
- Asthmaasthma5.5%37
- Diarrhoealoose or frequent stools5.5%37
- Poor venous access5.5%37
Top 30 of 446 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 human c1 esterase 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
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 3,328 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
Patient sex
Who reported
Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 35.4% of reports give the United States as the country of the event or reporter.
Reason for use recorded
| Indication as recorded (MedDRA) | Reports | Share |
|---|---|---|
| Hereditary angioedema | 256 | 38.3% |
| Immune system disorder | 130 | 19.4% |
| Prophylaxis | 77 | 11.5% |
| Hereditary angioedema with c1 esterase inhibitor deficiency | 36 | 5.4% |
| Angioedema | 32 | 4.8% |
| Hereditary angioedema with normal c1 esterase inhibitor | 27 | 4% |
The indication field is filled in by the reporter and is often blank; shares are of all 669 reports.
In context
| Measure | Human c1-esterase inhibitor | Human C1 esterase inhibitor | All reports |
|---|---|---|---|
| Reports as suspect product | 669 | 3,328 | 20,646,523 |
| Share of that pool | — | 20.1% | 0% |
| Reports, latest 12 months | 54 | — | 1,332,454 |
| Marked serious | 97.9% | 84% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 102 | 49 | 91 |
| Hospitalisation recorded, per 1,000 reports | 502 | 503 | 213 |
| Consumer-filed share | 37.4% | 38.3% | 45.8% |
| Top term, share of reports | Hereditary angioedema 52.5% | median 51.6% | 0.1% |
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 human c1 esterase inhibitor class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Cinryze | brand | 2,659 | 32 | 80.6% |
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 Human c1-esterase inhibitor reports
How many adverse event reports has FDA received for Human c1-esterase inhibitor?
669 reports list Human c1-esterase inhibitor as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 54 of them arrived in the latest 12 months. Another 42 list it only as a concomitant medication.
What reactions are recorded in Human c1-esterase inhibitor reports?
hereditary angioedema (52.5%), off label use (28%), drug ineffective (18.8%), product dose omission issue (13.6%) and inappropriate schedule of product administration (11.2%). 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 Human c1-esterase inhibitor was responsible.
How serious are the reports?
97.9% are marked serious by the reporter. Among the outcomes recorded, 10.2% of reports include death and 50.2% 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 (47.2%), consumer or non-health professional (37.4%) and physician (14.6%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Human c1-esterase inhibitor rising?
54 reports in the 12 months to June 2026, down 66% from 161 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 Human c1-esterase inhibitor 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 Human c1-esterase inhibitor?
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 Human c1-esterase inhibitor as a suspect or interacting product; reports listing it only as a concomitant medication (42) 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.