Icatibant — Complete Research Guide (2026)

Last updated 2026-06-30

What is Icatibant?

Icatibant (brand name Firazyr) is a synthetic decapeptide that acts as a selective bradykinin B2-receptor antagonist, given by subcutaneous injection.

It is FDA-approved (2011) and EMA-approved for acute attacks of hereditary angioedema (HAE) in adults, and in some regions can be self-administered.

Its evidence base is the randomized, controlled FAST-1, FAST-2, and FAST-3 trials.

How does Icatibant work?

In hereditary angioedema, excess bradykinin acting on B2 receptors increases vascular permeability and causes swelling.

Icatibant competitively blocks the bradykinin B2 receptor, interrupting this signal and reducing the angioedema attack.

What does the research say about Icatibant?

• In the FAST-1 and FAST-2 trials, icatibant shortened the time to symptom relief for acute HAE attacks compared with placebo or an active comparator. ^[1]
• The placebo-controlled FAST-3 trial confirmed that icatibant significantly reduced time to symptom relief for acute cutaneous, abdominal, and laryngeal HAE attacks. ^[2]
• Open-label and extension data showed icatibant was effective for treating repeated/multiple HAE attacks over time. ^[3]

Clinical research & studies

The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.

• [1] Icatibant, a new bradykinin-receptor antagonist, in hereditary angioedema — Cicardi M et al., New England Journal of Medicine 2010. (Randomized controlled trials (FAST-1 and FAST-2))
• [2] Randomized placebo-controlled trial of the bradykinin B2 receptor antagonist icatibant for the treatment of acute attacks of hereditary angioedema: the FAST-3 trial — Lumry WR et al., Annals of Allergy, Asthma and Immunology 2011. (Randomized placebo-controlled trial (FAST-3))
• [3] Icatibant for Multiple Hereditary Angioedema Attacks across the Controlled and Open-Label Extension Phases of FAST-3 — Lumry WR et al., International Archives of Allergy and Immunology 2015. (Controlled trial with open-label extension)
• [4] Repeat treatment of acute hereditary angioedema attacks with open-label icatibant in the FAST-1 trial — Malbran A et al., Clinical and Experimental Immunology 2014. (Open-label extension (FAST-1))
• [5] Repeat treatment with icatibant for multiple hereditary angioedema attacks: FAST-2 open-label study — Bas M et al., Allergy 2013. (Open-label study (FAST-2))
• [6] Evidence-based recommendations for the therapeutic management of angioedema owing to hereditary C1 inhibitor deficiency: consensus report of an International Working Group — Cicardi M et al., Allergy 2012. (International consensus/guideline)

Dosing context

This is context only and not medical advice: in trials icatibant was given as a single fixed-dose subcutaneous injection at the onset of an acute attack, with the option of repeat doses if symptoms persisted or recurred, up to a daily maximum.

In several regions patients are trained for self-administration, but laryngeal (throat) attacks still warrant emergency care.

Side effects & safety profile

The most common adverse events are injection-site reactions, including redness, swelling, warmth, and itching at the subcutaneous injection site, which are usually transient.

Icatibant is generally well tolerated, and unlike some HAE therapies it does not carry a boxed warning.

Laryngeal attacks still require emergency medical attention because of airway risk.

Stacking & combinations

Icatibant is an on-demand prescription treatment for acute HAE attacks and is used under a specialist HAE management plan, not combined with unregulated peptides.

Finding Icatibant vendors

User reviews

Frequently asked questions

References

1. [1] Icatibant, a new bradykinin-receptor antagonist, in hereditary angioedema — Cicardi M et al., New England Journal of Medicine 2010. PMID: 20818888. View sourceStudy: Randomized controlled trials (FAST-1 and FAST-2)Icatibant shortened time to clinical relief of acute HAE attacks versus control.
2. [2] Randomized placebo-controlled trial of the bradykinin B2 receptor antagonist icatibant for the treatment of acute attacks of hereditary angioedema: the FAST-3 trial — Lumry WR et al., Annals of Allergy, Asthma and Immunology 2011. PMID: 22123383. View sourceStudy: Randomized placebo-controlled trial (FAST-3)Icatibant significantly reduced time to symptom relief versus placebo for acute HAE attacks.
3. [3] Icatibant for Multiple Hereditary Angioedema Attacks across the Controlled and Open-Label Extension Phases of FAST-3 — Lumry WR et al., International Archives of Allergy and Immunology 2015. PMID: 26556097. View sourceStudy: Controlled trial with open-label extensionIcatibant was consistently effective and well tolerated across multiple treated HAE attacks.
4. [4] Repeat treatment of acute hereditary angioedema attacks with open-label icatibant in the FAST-1 trial — Malbran A et al., Clinical and Experimental Immunology 2014. PMID: 24749847. View sourceStudy: Open-label extension (FAST-1)Repeated icatibant dosing remained effective for recurrent HAE attacks.
5. [5] Repeat treatment with icatibant for multiple hereditary angioedema attacks: FAST-2 open-label study — Bas M et al., Allergy 2013. PMID: 24111645. View sourceStudy: Open-label study (FAST-2)Icatibant maintained efficacy and tolerability across multiple HAE attacks.
6. [6] Evidence-based recommendations for the therapeutic management of angioedema owing to hereditary C1 inhibitor deficiency: consensus report of an International Working Group — Cicardi M et al., Allergy 2012. PMID: 22126399. View sourceStudy: International consensus/guidelinePositions icatibant among recommended on-demand therapies for acute HAE attacks.