Hydroxyzine-induced Torsade de Pointes in a Patient with Complete Atrioventricular Block.

An 82-year-old woman was admitted to our hospital because of dyspnea and bradycardia during exertion. Electrocardiography revealed complete atrioventricular block. During pacemaker implantation, a small dose (12.5 mg) of hydroxyzine was injected for sedation, and torsade de pointes (Tdp) occurred. The QT interval was prolonged after administration of hydroxyzine, and Tdp was observed after the R on T phenomenon occurred, indicating that hydroxyzine was capable of prolonging the QT interval and causing Tdp. Therefore, we must be cautious when administering hydroxyzine for sedation during surgery, especially in patients with bradycardia.