Angiotensin II Receptor Blockers in Patients with ACE Inhibitor–Induced Angioedema

OBJECTIVE: To determine the safety of using angiotensin II receptor blockers in patients who have experienced angioedema following treatment with angiotensin-converting enzyme (ACE) inhibitors. DATA SOURCES: Clinical literature identified through MEDLINE (January 1966-August 1999). Key search terms included angioneurotic edema, angiotensin-converting enzyme inhibitors, receptors-angiotensin, and losartan. DATA SYNTHESIS: ACE inhibitor-induced angioedema occurs with an incidence of 0.1-0.5%. Alternative therapy is necessary for patients who experience this potentially life-threatening adverse effect. Since angiotensin II receptor blockers do not increase concentrations of bradykinin, the proposed mechanism of ACE inhibitor-induced angioedema, they were presumed to be safe alternatives. Recent case reports, however, document angioedema following therapy with angiotensin II receptor blockers; 32% of the reported patients experienced a prior episode of angioedema attributed to ACE inhibitor therapy. CONCLUSIONS: Until the exact cause of both ACE inhibitor- and angiotensin II receptor blocker-induced angioedema is determined, angiotensin II receptor blockers should be used with extreme caution in patients with a prior history of angioedema.