Icatibant (trade name Firazyr) is a synthetic peptidomimetic drug consisting of ten amino acids, and acts as an effective and specific antagonist of bradykinin B2 receptors. It has been approved in the EU for use in hereditary angioedema, and is under investigation for a number of other conditions in which bradykinin is thought to play a significant role. Icatibant currently has orphan drug status in the United States and FDA approved on August 25, 2011. Icatibant inhibits bradykinin from binding the B2 receptor and thereby treats the clinical symptoms of an acute, episodic attack of HAE.

Hemin (trade name Panhematin) is a protoporphyrin IX containing a ferric iron ion (heme B) with a chloride ligand, which is is indicated for the amelioration of recurrent attacks of acute intermittent porphyria temporally related to the menstrual cycle in susceptible women. Manifestations such as pain, hypertension, tachycardia, abnormal mental status and mild to progressive neurologic signs may be controlled in selected patients with this disorder. the therapy for the acute porphyrias is not curative. Heme acts to limit the hepatic and/or marrow synthesis of porphyrin. This action is likely due to the inhibition of δ-aminolevulinic acid synthetase, the enzyme which limits the rate of the porphyrin/heme biosynthetic pathway. The exact mechanism by which hematin produces symptomatic improvement in patients with acute episodes of the hepatic porphyrias has not been elucidated.

Ecallantide (DX-88) is a potent and specific inhibitor of plasma kallikrein. Ecallantide is a recombinantly produced and engineered small protein based on the first Kunitz domain of human tissue factor pathway inhibitor. It was identified through phage display technology. Ecallantide binds to plasma kallikrein and blocks its binding site, inhibiting the conversion of HMW kininogen to bradykinin. Hereditary angioedema (HAE) resulting from the deficiency of the C1 inhibitor protein is a rare disease, characterized by paroxysms of edema formation in the subcutis and in the submucosa. Edema can cause obstruction of the upper airway, which may lead to suffocation. Prompt elimination of edema is necessary to save patients from this life-threatening condition. Essentially, these edematous attacks are related to the activation of the kinin-kallikrein system and the consequent release of bradykinin. Ecallantide (KALBITOR) is a plasma kallikrein inhibitor indicated for treatment of acute attacks of hereditary angioedema (HAE) in patients 12 years of age and older.