Torsades de pointes induced by concomitant use of chlorpheniramine and propranolol: An unusual presentation with no QT prolongation

Drug-induced torsades de pointes (TdP) is a rare but potentially fatal adverse effect of commonly prescribed medications including cardiac and noncardiac drugs. Importantly, many drugs have been reported to cause the characteristic Brugada syndrome-linked electrocardiography (ECG) abnormalities and/or (fatal) ventricular tachyarrhythmias. Chlorpheniramine and propranolol have the arrhythmogenic effects reported previously. A review of literature revealed a large number of case reports of chlorpheniramine or propranolol use resulting in QTc prolongation, TdP, or both. However, we wish to report the case of a patient who was treated with a combination of chlorpheniramine and propranolol, whose ECG showed no QT prolongation but who suffered from cardiac arrest due to TdP.