Bradykinin B2 receptor antagonist Pregnancy: No clinical data on exposed pregnancies. Animal studies showed effects on uterine implantation and parturition; the potential risk for humans is unknown. Should be used during pregnancy only if the potential benefit justifies the potential risk to the foetus (e.g. for treatment of potentially life-threatening laryngeal attacks). Breast-feeding women who take icatibant should not breastfeed for 12 hours after treatment (§4.6).

Icatibant

Brand names: Firazyr

Icatibant is a selective bradykinin B2 receptor antagonist used for the acute treatment of attacks of hereditary angioedema in adults and adolescents with C1-esterase inhibitor deficiency.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 30 mg

Route: Subcutaneous injection, preferably in the abdominal area (injected slowly)

Frequency: Single injection; in case of insufficient relief or recurrence of symptoms a second injection may be given after 6 hours, and a third injection after a further 6 hours

Max: No more than 3 injections in a 24-hour period

eMC §4.2 (acute attacks of hereditary angioedema). In the majority of cases a single injection is sufficient to treat an attack. In clinical trials not more than 8 injections per month were administered. Intended for use under the guidance of a healthcare professional; may be self-administered or given by a caregiver only after training in subcutaneous injection technique, and the first-ever treatment should be given in a medical institution or under the guidance of a physician. For adults, subsequent doses required for the same attack should be administered within a medical institution. Patients with laryngeal attacks must be managed in an appropriate medical institution after injection until discharge is considered safe. PAEDIATRIC DOSING IS BY WEIGHT BAND, NOT PER KG (§4.2, children and adolescents aged 2 to 17 years): 12–25 kg = 10 mg (1.0 mL); 26–40 kg = 15 mg (1.5 mL); 41–50 kg = 20 mg (2.0 mL); 51–65 kg = 25 mg (2.5 mL); >65 kg = 30 mg (3.0 mL). No dosage regimen can be recommended for children under 2 years or under 12 kg. In the paediatric clinical trial not more than 1 injection per HAE attack was administered, and icatibant may only be administered by a trained caregiver in this age group. Verify paediatric use against a children's formulary. Elderly: limited information in patients over 65 years, who have increased systemic exposure.

Dose adjustments

Renal

No dose adjustment is required in patients with renal impairment (§4.2). No dose adjustment is required in hepatic impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients

Side effects

Injection site reactions (very common) — bruising, haematoma, burning, erythema, irritation, numbness, oedema, pain, pruritus, swelling, urticaria, warmth
Dizziness and headache (common)
Nausea (common)
Rash, erythema, pruritus (common); urticaria (frequency not known)
Pyrexia and increased transaminases (common)

Interactions

ACE inhibitors — co-administration has not been studied; ACE inhibitors are contraindicated in HAE patients due to possible enhancement of bradykinin levels (§4.5)
Pharmacokinetic drug interactions involving CYP450 are not expected (§4.5)

Clinical monograph

How it works

It competitively blocks the bradykinin B2 receptor, preventing bradykinin-mediated vasodilation and increased vascular permeability that drive the swelling of hereditary angioedema attacks.

Prescribing in practice

It treats acute attacks and does not prevent them, so laryngeal or airway involvement still requires urgent assessment and airway management; patients with airway attacks should seek emergency care even after dosing.
Administered by subcutaneous injection, typically into the abdominal area, and may be given as a self-administered or carer-administered dose after appropriate training.
A repeat dose may be needed if the attack persists or recurs; injection-site reactions are very common. Consult the SPC for details.

Monitoring

Monitor the clinical response of the attack, watching especially for airway compromise in laryngeal attacks, and observe injection-site reactions.

Counselling the patient

This injection treats an attack as it happens and does not stop future attacks.
Always seek emergency help for any throat or tongue swelling or difficulty breathing, even after injecting.
Redness, swelling, or burning at the injection site is common and usually settles within hours.

Evidence & guidelines

Icatibant is licensed for acute hereditary angioedema attacks based on randomised controlled trials demonstrating faster symptom relief versus comparator, and is recommended in international angioedema management guidance.

Reference: NICE TA484; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Myasthenia Gravis Activities of Daily Living (MG-ADL) Scale · Neuromuscular

Pathways

📚 MRCEM Revision

Featured in these MRCEM clinical pathways

Icatibant is a core drug in the following exam-focused workups on our sister siteReviseMRCEM.

Anaphylaxis

MRCEM Primary / Intermediate / OSCE candidates: each pathway includes exam-style questions, RCEM/NICE citations, and FAQ summaries.