Peptide Data grades most research peptides at Limited or Anecdotal because the human data is thin. Icatibant is a counterexample: a synthetic peptide that holds a UK marketing authorisation and a full clinical development record in a rare disease.
1. What icatibant is
Icatibant is a synthetic decapeptide — ten amino acids — engineered as a selective antagonist at the bradykinin B2 receptor. It is supplied as Firazyr and given by subcutaneous injection under medical supervision. It is not a research compound and is not sold as one.
2. The biology it sits on
Hereditary angioedema (HAE) is caused by an absence or dysfunction of C1-esterase inhibitor, a regulator of the factor XII/kallikrein cascade. When that brake fails, bradykinin production is unopposed; bradykinin is a vasodilator and is understood to drive the localised swelling, inflammation and pain of an HAE attack. Icatibant competes with bradykinin at the B2 receptor, with an affinity similar to bradykinin itself.
3. The UK licensing position
Firazyr holds a UK marketing authorisation and is a prescription-only medicine (POM). Icatibant was first licensed in the European Union for acute HAE attacks in adults; the label was later extended to adolescents and children, and the UK authorisation carried over at the end of the transition period. Under the Medicines Act 1968 and the Human Medicines Regulations 2012 it is a licensed medicine supplied on prescription. That status is the exception in the peptide field, not the rule.
4. What the clinical record shows — and where it is cautious
Icatibant was evaluated in randomised, controlled trials in acute HAE attacks. Evidence grade: Strong for its licensed indication. Two label cautions are worth repeating. First, under ischaemic conditions, B2 antagonism could theoretically worsen cardiac function and reduce coronary blood flow, so caution is advised in acute ischaemic heart disease or unstable angina. Second, there is a theoretical concern that B2 blockade may attenuate the late neuroprotective phase of bradykinin after stroke. Icatibant is not indicated for either setting; those cautions are recorded here rather than implied.
5. What icatibant does not tell you
A licensed peptide medicine does not license the rest of the field. Icatibant's cleared development programme says nothing about the evidence base for unlicensed compounds graded Limited or Anecdotal elsewhere on this site. Different molecule, different data, different regulatory footing.
6. The research-use-only line
This article is a regulatory and pharmacological record, not consumption advice. Icatibant is a prescription-only medicine in the UK and is not a research chemical. Research peptides remain research-use only: Peptide Data does not provide dosing information for human use, and nothing here should be read as an instruction to obtain or administer any compound.
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This article is AI-researched and editorially reviewed. It is provided for research and educational purposes only and is not medical advice. Research peptides are not licensed for human consumption in the UK.