Torsades de pointes associated with chlorpromazine: Case report and reviewof associated ventricular arrhythmias

Purpose. To present a case of chlorpromazine-associated torsades de pointes , review established cases of ventricular arrhythmias associated with chlor promazine, and describe the proarrhythmic characteristics of this drug. Data Sources. Articles identified through a search of MEDLINE and IDIS from January 1966-November 2000 and thorough review of the article bibliographi es. Patient cases also were identified from a search of the Food and Drug A dministration's Adverse Event Reporting System database (November 1997-Marc h 2001). Cases involving intentional overdoses of chlorpromazine were exclu ded. Results. In addition to the case reported herein, 12 cases of documented, c hlorpromazine-associated ventricular arrhythmias were identified; five had characteristic features of torsades de pointes. Chlorpromazine delayed repo larization and produced electrocardiographic abnormalities; although, wheth er chlorpromazine induced torsades de pointes through a mechanism of early afterdepolarizations is unclear. Similar to other instances of drug-induced torsades de pointes, concurrent factors such as electrolyte deficiencies m ay place the patient at increased risk for arrhythmia. Conclusions. Chlorpromazine can delay repolarization and produce electrocar diographic abnormalities. These can result infrequently in ventricular arrh ythmias and torsades de pointes, particularly in patients with confounding factors.