Abstract
BACKGROUND: Striking prolongation of the QT interval and the morphologically distinctive polymorphic ventricular tachycardia torsades de pointes can occur in patients treated with antiarrhythmic drugs and certain non-cardiovascular medications. However, there have been no reported cases of QT prolongation and torsades de pointes associated with the antiviral agent oseltamivir. OBJECTIVE: To determine whether exposure to oseltamivir is associated with increased risk of QT prolongation and torsades de pointes in patients treated for H1N1 influenza. METHODS: Two unusual case histories of patients exposed to oseltamivir who developed marked QT prolongation and torsades de pointes were examined. RESULTS: Two patients on stable doses of sotalol for atrial fibrillation developed marked QT prolongation and torsades de pointes following administration of the antiviral agent. CONCLUSIONS: The recent H1N1 pandemic has necessitated treatment of suspected or confirmed cases of H1N1 influenza with oseltamivir. Although the precise mechanism for this drug-drug interaction is not clear, given the large number of people expected to receive oseltamivir this winter, it is important to highlight this potentially adverse event.