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# Hereditary angioedema agents

Drugs that stop or prevent bradykinin swelling in hereditary angioedema: C1 inhibitor, a bradykinin receptor blocker and kallikrein inhibitors.

Updated Nov 1, 2026

## What they are

Hereditary angioedema is usually due to a lack or poor function of C1 inhibitor. Without it, plasma kallikrein overproduces bradykinin, which causes deep swelling of the skin, gut or airway, without hives and without response to antihistamines. Some agents treat acute attacks (C1 inhibitor, icatibant); others prevent them (C1 inhibitor, lanadelumab, berotralstat).

## Mechanism of action

C1 inhibitor concentrates replace the missing protein, which restrains plasma kallikrein and activated factor XII. Kallikrein inhibitors (lanadelumab, berotralstat, ecallantide) stop the enzyme from cutting high-molecular-weight kininogen into bradykinin. Icatibant blocks the B2 receptor that bradykinin acts on.

Target: Kallikrein-kinin system: plasma kallikrein, bradykinin B2 receptor, C1 inhibitor

## Key points

- Bradykinin angioedema: no hives, no itch, no response to antihistamines, corticosteroids or usually epinephrine
- Acute attack: C1 inhibitor concentrate or icatibant; prevention: C1 inhibitor, lanadelumab or berotralstat
- Throat swelling is an emergency even after self-treatment
- ACE inhibitors also cause bradykinin angioedema

## Drugs in this class

- [**C1 esterase inhibitor** A concentrate of the plasma protein missing in hereditary angioedema; it treats acute attacks and prevents them by… Proteases it inhibits: plasma kallikrein, activated factor XII and complement C1r/C1s](https://durgical.com/en/pharmacology/c1-esterase-inhibitor/)
- [**Icatibant** A synthetic peptide that blocks the bradykinin B2 receptor; injected under the skin, it treats acute attacks of… Bradykinin B2 receptor (G-protein–coupled)](https://durgical.com/en/pharmacology/icatibant/)
- [**Lanadelumab** A human antibody that blocks plasma kallikrein; injected under the skin at intervals, it prevents hereditary… Plasma kallikrein](https://durgical.com/en/pharmacology/lanadelumab/)
- [**Berotralstat** An oral small-molecule plasma kallikrein inhibitor taken daily to prevent hereditary angioedema attacks. Plasma kallikrein (serine protease)](https://durgical.com/en/pharmacology/berotralstat/)

## Others in the class

- ecallantide
- conestat alfa (recombinant C1 inhibitor)
- garadacimab
- sebetralstat
- donidalorsen

## Test yourself

Think of the answer, then tap the question to see it.

## Which mediator causes swelling in hereditary angioedema?

Bradykinin.

## Which receptor does icatibant block?

The bradykinin B2 receptor.

## Which oral drug prevents hereditary angioedema attacks?

Berotralstat, a plasma kallikrein inhibitor.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=B06AC&showdescription=no) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); [Icatibant injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a623036.html) (MedlinePlus (U.S. National Library of Medicine), 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/classes/hereditary-angioedema-agents/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/hereditary-angioedema-agents/