A Rare Case of Dose-Dependent Losartan-Induced Angioedema

Angiotensin converting enzyme inhibitors (ACE-Is) have long been associated with angioedema and cough. These complications are thought to be related to an increase in bradykinin levels. Angiotensin receptor blockers (ARBs) such as losartan, however, are not known to increase bradykinin levels and, therefore, this complication is not as widely recognized. However, there is a significant proportion of patients who develop angioedema on ARB medications after previous episodes of angioedema on ACE-I. Though there is increasing literature to support that the patients may develop angioedema while taking ARBs such as losartan, a dose-dependent nature has not been well documented. We present a patient with a 20-year history of losartan use who developed angioedema suddenly after an increase in dosage. A dose-dependent relationship between ARBs and angioedema has not been well documented and this is the first documented case of angioedema presenting in a dose-dependent manner with losartan use. We hope that our case will bring awareness to the potential dose-dependent relationship between losartan and angioedema in order to aid clinicians when titrating ARB medications in order to expediently diagnose the fatal side-effect of angioedema and to encourage further research.