Evidence Grade A — Regulatory approved. 760 published studies. 33 registered clinical trials.
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Icatibant (sold as Firazyr) is a self-injectable rescue treatment for sudden swelling attacks in hereditary angioedema (HAE) — a rare genetic condition that causes unpredictable episodes of severe swelling in the face, throat, hands, feet, or abdomen. It works by blocking the molecule (bradykinin) directly responsible for the swelling, typically providing noticeable relief within about two hours.
Icatibant is also known by these brand and alternate names:
760 published studies: 434 human, 216 animal, 53 in-vitro, 150 reviews
Icatibant is marketed as Firazyr (approved August 2011) for the treatment of acute hereditary angioedema attacks in adults. It is self-administered as a subcutaneous injection from a prefilled syringe.
In clinical trials, icatibant provided symptom relief in a median of 2 hours compared to nearly 20 hours for placebo, with most patients experiencing significant improvement from a single injection. Generic icatibant has become available, improving access. The self-injection format is a significant practical advantage for a condition where swelling attacks are unpredictable and can become life-threatening if the airway is involved — patients can carry and administer the medication immediately without waiting for hospital treatment.
In hereditary angioedema, a missing protein (C1-inhibitor) leads to excessive production of bradykinin, a small molecule that makes blood vessel walls leak fluid into surrounding tissues, causing rapid and sometimes life-threatening swelling. Icatibant is a modified version of bradykinin itself — redesigned with five non-natural amino acids that convert it from an activator to a blocker of the bradykinin B2 receptor. It competitively occupies the receptor, preventing bradykinin from triggering the vascular leakage that causes swelling.
Clinical trials showed icatibant provided symptom relief in a median of 2 hours, compared to nearly 20 hours with placebo. The ability for patients to carry and self-inject the medication from a prefilled syringe is particularly important for a condition where attacks are unpredictable and throat swelling can be life-threatening — waiting for hospital treatment is not always feasible. Generic icatibant has become available, improving access for this rare disease population. Injection-site reactions occur in virtually all patients (97%) but are generally mild and short-lived. A trial investigating icatibant for ACE-inhibitor-related angioedema (a more common type of swelling) was terminated without conclusive results. No direct comparison trials exist between icatibant and the other HAE attack treatments (ecallantide or C1-inhibitor concentrate).
PeptideTrace tracks 33 registered clinical trials for Icatibant sourced from ClinicalTrials.gov.
AMelioration of Angiotensin Converting Enzyme Inhibitor Induced Angioedema Study
A Study Observing US Patients With HAE Type I or II Who Take Icatibant to Treat HAE Attacks
A Study to Explore Hereditary Angioedema (HAE) Symptoms and Treatment Patterns in Korean People
A Study to Evaluate the Safety and Efficacy of Icatibant in Patients With Bradykinin Induced Angioedema
A Study of Lanadelumab (Takhzyro) and Icatibant (Firazyr®) in Persons With HAE in China
EMA Marketing Authorisation
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Health Canada Market Authorisation
FDA SUPPL 2
FDA SUPPL 12
FDA SUPPL 3
Icatibant is a synthetic decapeptide (10 AA), selective bradykinin B2 receptor antagonist. MW 1,304.5 Da. Modified bradykinin analogue with five non-natural amino acids (D-Arg, Hyp, Thi x2, D-Tic). Converts agonist to potent antagonist with metabolic stability. SC 30 mg self-administered. Half-life ~1-2 hours, symptomatic relief within 30 minutes.
Competitive antagonist at bradykinin B2 receptor (KB2R, ~1.4 nM). In HAE, C1-inhibitor deficiency causes excess bradykinin. Bradykinin via B2R activates Gq/G11, PLC, eNOS, increasing vascular permeability causing edema. Icatibant blocks B2R, preventing bradykinin-mediated vasodilation and leakage. Non-natural amino acids resist kininase degradation.
Marketed as Firazyr. Approved August 25, 2011. FAST-1 (N=56): primary endpoint NS. FAST-2 (N=74): median relief 2.0 vs. 12.0 hours vs. tranexamic acid (P<0.001). FAST-3 (N=98): 2.0 vs. 19.8 hours vs. placebo (P<0.001). Pediatric (N=32, ages 2-17) confirmed. Indication: acute HAE attacks in adults >=18.
Vancomycin is marketed as Vancocin and Firvanq (approved 1958, with oral solution Firvanq approved 2018). It is the standard treatment for serious MRSA infections (bloodstream infections, endocarditis, pneumonia, bone infections) and is first-line for severe C. difficile colitis. Vancomycin requires therapeutic drug monitoring — blood levels must be checked regularly to ensure the dose is effective without causing kidney damage or hearing loss. The rise of vancomycin-resistant enterococci (VRE) and occasional vancomycin-intermediate S. aureus (VISA) strains represent ongoing challenges. Despite being nearly 70 years old, vancomycin remains irreplaceable for many serious infections, though newer alternatives like daptomycin and the lipoglycopeptides offer advantages in specific settings.
Zilucoplan is marketed as Zilbrysq (approved October 2023) for anti-acetylcholine receptor antibody-positive generalised myasthenia gravis in adults. Administered as a daily subcutaneous self-injection. In the RAISE trial, zilucoplan showed statistically significant improvements in both activities of daily living and quantitative muscle strength scores compared to placebo, with improvements evident from week one. Its key differentiator from existing complement inhibitors (eculizumab, ravulizumab) is the self-injectable format — those alternatives require hospital-based intravenous infusions. As with all complement inhibitors, patients require meningococcal vaccination before starting treatment due to increased susceptibility to meningococcal infection.
Daptomycin is marketed as Cubicin (approved September 2003). It is indicated for complicated skin and soft tissue infections and S. aureus bloodstream infections including right-sided endocarditis. Administered as a once-daily intravenous infusion. A key limitation is that daptomycin cannot be used for pneumonia — lung surfactant inactivates the drug. In the bacteraemia trial, daptomycin was non-inferior to vancomycin with significantly lower rates of kidney problems (11% versus 26%). Creatine kinase (CK) levels must be monitored during treatment, as daptomycin can cause muscle toxicity. Generics became available after patent expiry, significantly reducing cost.
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