Clinical characteristics of angiotensin-converting enzyme inhibitor-induced angioedema.

We present the cases of two patients with angiotensin-converting enzyme (ACE) inhibitor-induced angioedema that required intubation for life-threatening airway compromise. This side effect has been previously reported with all ACE inhibitors, but its incidence and potential for a fatal outcome may not be fully appreciated. A review of the literature reveals 227 reports of this reaction with an overall incidence of approximately 0.1% to 0.2%. The etiology is nonimmunogenic and thought to be related to accentuated bradykinin activity. There is no clinical profile that identifies patients at increased risk for this side effect. There are unique clinical characteristics to this idiosyncratic reaction: angioedema may suddenly occur even though the drug has been well tolerated for months or years; symptoms may regress spontaneously while the patient continues the medication, erroneously prompting an alternative diagnosis; the pathology has a special predilection for the tongue, a circumstance that renders orotracheal and nasotracheal intubation difficult; symptoms may progress rapidly despite aggressive medical therapy, necessitating emergency airway procedures; and a rebound phenomenon following successful medical therapy has been described. We recommend intensive medical treatment before angioedema is severe enough to thwart standard methods to ensure a protected airway. Once even minor angioedema is attributed to an ACE inhibitor, an alternative class of antihypertensive medication should be chosen. Individuals with a history of idiopathic angioedema probably should not be given ACE inhibitors.