Icatibant [1,2] is indicated in the EU for the symptomatic treatment of acute attacks in patients with hereditary angioedema (HAE). HAE is a rare disease (occurring in about 1/10 000 to 1/50 000 people) characterized by an absent or dysfunctional Cl esterase inhibitor molecule (C1INH). C1INH is an important regulator in the metabolic pathways of complement, kinin-kallikrein and coagulation factors. The symptoms of the disease are due to local accumulations of bradykinin caused by excessive activation of the complement and kinin pathways as a result of the C1INH deficiency. Bradykinin, a potent inflammatory mediator, causes vasodilatation, stimulates nociceptors and increases vascular permeability, leading to rapid accumulation of fluid in the interstitial tissue with swelling, pain and redness of the affected tissues. These symptoms are mediated by bradykinin B2 receptors. Attacks can be life threatening when laryngeal oedema occurs. Icatibant, an orphan drug, is a selective, competitive B2 receptor antagonist.
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