Pyrilamine-Induced Prolonged QT Interval in Adolescent With Drug Overdose

The widespread availability of antihistamines in many over-the-counter preparations can lead to significant hazard to the public because of their possible link to potential ventricular arrhythmias secondary to prolongation of QT interval. The effect can be further compounded by the use of other commonly used medications such as macrolides, antifungal agents, antipsychotics, and other antihistamine-containing preparations. The effect of antihistamines on QT interval is not a class effect but is unique to certain medications. Pyrilamine, a first-generation antihistaminic agent, is considered safe as there are no reports regarding its cardiac toxicity available in literature. We report a case of an adolescent with prolonged QT interval after an overdose of pyrilamine.