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Icatibant

EvidenceFDA approved

ClassBradykinin B2 antagonist

Icatibant is an FDA-approved peptide that blocks the bradykinin B2 receptor in hereditary angioedema attacks. Learn how it works and its side effects.

Reviewed by: William Maish, MD MBA MPH, Clinical Product Lead
Published: October 5, 2026
Last updated: October 5, 2026

Key takeaway

Icatibant (sold as Firazyr) is a peptide that blocks the bradykinin B2 receptor, used to treat acute attacks of hereditary angioedema, a condition of sudden, severe swelling. By blocking the mediator that drives the swelling, it shortens attacks. It has been FDA-approved in the U.S. since 2011 and can be self-administered as a subcutaneous injection.

At a glance

What it is	A bradykinin B2 receptor antagonist peptide
Approved for	Acute attacks of hereditary angioedema in adults
Key fact	In the FAST-3 trial it cut the time to meaningful symptom relief from about 20 hours to 2 hours versus placebo
Route	Subcutaneous injection, self-administered into the abdomen
Evidence strength	FDA approved

What is icatibant?

Icatibant, sold under the brand Firazyr, is a synthetic ten-amino-acid peptide that blocks the bradykinin B2 receptor. It is used for acute attacks of hereditary angioedema (HAE), a genetic disorder in which episodes of severe swelling affect the skin, abdomen, and sometimes the airway. It was developed under the code HOE 140 and approved in the United States in 2011.

How does icatibant work?

Icatibant targets bradykinin, the molecule responsible for the swelling in hereditary angioedema. In HAE, a deficiency or dysfunction of the C1 inhibitor protein leads to overproduction of bradykinin, which binds B2 receptors on blood vessels and makes them dilate and leak fluid into tissues, producing the characteristic swelling and pain. Icatibant is a selective competitive antagonist at the B2 receptor, so it blocks bradykinin from acting there and allows the attack to subside.

Because it acts directly at the receptor regardless of the upstream cause, it works in HAE attacks driven by bradykinin and can be given by the patient at the first sign of an attack. In the FAST-3 trial, icatibant shortened the median time to meaningful symptom relief¹ to about 2 hours, compared with roughly 20 hours on placebo.

Is it FDA-approved?

Yes. Icatibant was approved² by the FDA in 2011 for acute attacks of hereditary angioedema in adults, and generic versions are also available. It is formulated for subcutaneous self-injection.

What is icatibant prescribed for?

Icatibant is prescribed to treat acute attacks of hereditary angioedema in adults. Patients are typically trained to self-inject at the onset of an attack. Attacks involving the airway still warrant medical attention, even after treatment.

What are the side effects?

According to the prescribing information², common side effects include:

Injection-site reactions such as redness, swelling, pain, and itching, which are nearly universal
Fever
Dizziness

More serious considerations include:

Potential for delayed airway symptoms in laryngeal attacks, which should be monitored in a medical setting
Hives, reported after approval

More for skin & aging

Sources: FDA prescribing information for Firazyr; the FAST-3 trial (Lumry et al., Annals of Allergy, Asthma & Immunology, 2011, DOI: 10.1016/j.anai.2011.08.015¹), indexed on PubMed. This document is educational and does not constitute medical advice.