Angiotensin-converting enzyme (ACE) inhibitors block the catalysis of 
angiotensin I to angiotensin II and also the breakdown of bradykinin. ACE 
inhibitor-induced angioedema is mediated by inhibited bradykinin degradation 
leading to enhanced bradykinin plasma levels. The efficacy of currently used 
standard treatments with antiallergic drugs is questionable. A patient with 
acute ACE inhibitor-induced angioedema was treated with icatibant, a specific 
bradykinin B2 receptor antagonist approved for the treatment of hereditary 
angioedema. A single subcutaneous injection of 30 mg icatibant resulted in a 
rapid onset of symptom relief and a remarkable shortening of duration of the 
attack.