[Torsades de pointes caused by cetirizine overdose]

Abstract

Several therapeutic substances can cause torsades de pointes, especially if they prolong the QT interval and/or if there is an associated hypokalaemia. Certain second generation H1 antihistamines have been incriminated in the occurrence of such ventricular arrhythmias, such as terfenadine and astezimole, which have been withdrawn. Cetirizine, widely used in the treatment of allergic reactions, is a second generation H1 antihistamine with as yet no precautions of use regarding rhythm disturbances. No documented case of arrhythmia attributable to this drug has been reported. We report the case of a dialysed patient with chronic renal failure who had symptomatic episodes of torsades de pointes in the context of hypokalaemia and cetirizine overdose. In the light of this observation it would appear that the prescription of cetirizine is contra-indicated under such conditions.