KLK4 and angioedema: If ACEI-angioedema is dependent on bradykinin, then approaches that are effective for hereditary angioedema could be employed including infusion of C1 inhibitor (82), which inactivates enzymes involved in bradykinin formation, administration of Ecallantide (83) by subcutaneous injection to inactivate plasma kallikrein, or administration of Icatibant, a reversible bradykinin B2 receptor antagonist (32, 84).