Icatibant

Summary

Icatibant (brand name Firazyr) is a synthetic peptide that blocks the bradykinin B2 receptor. It is prescribed for acute attacks of bradykinin‑mediated angioedema, including hereditary angioedema (HAE), acquired angioedema, and angioedema linked to ACE‑inhibitor therapy. By preventing bradykinin from binding its receptor, icatibant reduces the swelling that can threaten the airway and cause painful facial or intestinal edema.

Mechanism of Action

Icatibant is a selective antagonist of the bradykinin B2 receptor, a G‑protein‑coupled receptor that mediates vasodilation and increased vascular permeability when activated by bradykinin. By occupying the receptor without activating it, icatibant blocks downstream signaling pathways that lead to endothelial leakage and tissue swelling. This antagonism counteracts the excessive bradykinin activity that underlies hereditary, acquired, and ACE‑inhibitor‑induced angioedema.

What the Research Shows

Clinical reviews describe icatibant as a newer therapeutic option for bradykinin‑mediated angioedema, noting its ability to improve outcomes where conventional antihistamines and corticosteroids fail. Studies on hereditary and acquired angioedema report its use alongside C1‑inhibitor concentrates. Interventional investigations of ACE‑inhibitor‑related angioedema have yielded mixed results, with some evidence of benefit in Caucasian patients but not in black patients. Overall, the literature supports icatibant’s role in acute management of bradykinin‑driven swelling, though data remain limited to relatively small or uncontrolled series.

Reported Benefits

Evidence from case series and interventional studies indicates that icatibant can rapidly reduce swelling in hereditary and acquired angioedema, providing an option when C1‑inhibitor therapy is unavailable or ineffective. Its targeted mechanism addresses the underlying bradykinin excess, offering relief where antihistamines and steroids are ineffective. Some reports suggest efficacy in ACE‑inhibitor‑induced angioedema, particularly in certain ethnic groups.

Limitations of the Evidence

The therapeutic benefit of icatibant in ACE‑inhibitor‑related angioedema is inconsistent, with conflicting interventional study results and possible ethnic differences in response. Most data derive from small, non‑randomised cohorts rather than large randomized trials, limiting certainty about optimal dosing, duration of effect, and comparative effectiveness versus other treatments. Evidence for long‑term safety and use in diverse populations remains sparse.

Safety Considerations

The abstracts do not detail specific adverse events, but icatibant is administered under prescription and should be used in settings where airway monitoring is possible. Its safety profile has not been fully characterised in the cited literature, so clinicians should remain vigilant for injection‑site reactions or unexpected systemic effects, and avoid reliance on it when standard therapies (C1‑inhibitor, fresh frozen plasma) are indicated.

How It Is Administered

Icatibant is supplied for subcutaneous injection. The approved formulation is administered by a healthcare professional or trained patient during an acute angioedema attack. It is not given orally or intravenously.

Routes of Administration

Goals & Uses

• Prevention of HAE attacksOff Label/InvestigationalLow
• ACE inhibitor-induced angioedemaInvestigationalModerate
• Bradykinin-mediated angioedema (non-HAE)InvestigationalLow
• Prevention of airway obstructionLife‑threatening Event MitigationHigh
• Acute hereditary angioedema attack reliefSymptom ControlHigh
• Acute treatment of hereditary angioedema attacksApproved IndicationHigh

Contraindications

• Unstable angina pectorisCardiovascularModerate
• Severe cardiovascular disease (unstable angina, recent MI)CardiovascularModerate
• Known hypersensitivity to icatibant or any excipientsAllergyHigh
• Ischemic heart diseaseCardiovascularModerate
• Hypersensitivity to icatibant or excipientsAllergyHigh

Adverse Effects

• RashDermatologicUncommonSkin eruption or discoloration
• Injection site reactionsLocalCommon
• HeadacheNeurologicCommonPain in the head or upper neck
• NauseaGastrointestinalUncommonFeeling of sickness or urge to vomit
• PyrexiaGeneralUncommon
• Transaminase elevationHepaticRare
• Injection site reactions (pain, erythema, swelling)LocalCommon
• DizzinessNeurologicUncommonFeeling faint, lightheaded, or unsteady

Drug Interactions

• C1‑esterase inhibitor concentratesLow
• ACE inhibitorsLow

Population Constraints

• PregnancyReproductive SafetyRelative
• Pediatric patients (<18 years)AgeAbsolute
• Pregnant or breastfeeding womenReproductiveRelative
• Pediatric patients under 2 yearsAgeAbsolute
• Severe hepatic impairmentOrgan ImpairmentRelative
• BreastfeedingReproductiveRelative

Regulatory Status

• European UnionApprovedApproved: Acute hereditary angioedema attacksEMA approval 2009.
• United StatesApprovedApproved: Acute hereditary angioedema attacks in adultsFDA approved 2008.
• United KingdomApprovedApproved: Acute hereditary angioedema attacksMHRA approval; same as EU.

Approved in the US (FDA 2008), EU, and UK for acute HAE attacks; marketed as Firazyr.

Evidence & Sources

• Bradykinin-mediated angioedema
  Journal ArticleModerateObtułowicz K2016-01-01T00:00:00.000000Z
• [Acquired angioedema]
  Journal ArticleModerateFain O, et al.2015-01-01T00:00:00.000000Z
• Bradykinin-mediated diseases
  Journal ArticleModerateKaplan AP2014-01-01T00:00:00.000000Z
• ACE inhibitor-mediated angioedema
  Journal ArticleModerateMontinaro V, Cicardi M2020-01-01T00:00:00.000000Z

Frequently Asked Questions