Drug-Induced Angioedema: A Rare Side Effect of Mirabegron

Drug induced angioedema can be allergic or non-allergic depending on the specific mediators leading to the reaction. Allergic angioedema is due to histamine release and has a rapid onset including an urticarial rash that responds to antihistamines and glucocorticoids. Non-allergic angioedema is likely due to increases in bradykinin, and has a much slower onset without an urticarial rash; it only resolves with discontinuation of the offending medication. Mirabegron, a beta 3-adrenergic receptor agonist, is widely prescribed medication for urinary urge incontinence and overactive bladder. This case report presents a patient with angioedema following the use of mirabegron for urinary incontinence whose angioedema symptom had been previous misattributed. The history, clinical examination, and diagnostic parameters led to the diagnosis of mirabegron induced angioedema and she was successfully treated with discontinuation of the medication. Though rare, angioedema is a side effect of mirabegron and can be life-threatening. Therefore thorough history taking and a high index of suspicion are crucial to correlate relevant exposure and onset of symptoms and should be considered in all patients on the medication who have a consistent presentation.