Atypical Antipsychotics and the QT Interval from the Cardiologist’s Aspect

Overview

So-called atypical antipsychotic drugs were introduced into medical practice with the aim ofminimizing disadvantages or adverse effects of conventional antipsychotics. However, possibleoccurrences of torsade de pointes type of malignant ventricular tachyarrhythmia are increasinglydiscused in relation to their use. The goal of this review is a closer look at the problem, particularlythe explanation of the mechanism of torsade de pointes, its clinical manifestation, and associationwith the electrocardiographic QT interval. The review considers the issues of prevention andcurrent requirements concerning individual drug safety. The occurrence of torsade de pointescan be better predicted using experimental data at the level of respective ion channel blockade,by identification of percentage of patients with significant QT interval prolongation (above 500ms) during the treatment and/or analysis of drug interactions.No association between torsade de pointes arrhytmias (or sudden death) and the use of olanzapine,quetiapine, risperidone and ziprasidone has been documented so far, despite certain degree ofQT interval prolongation described following administration of these drugs. It is, however, advisableto follow certain general preventive measures to minimize potential treatment risks. Giventhe potential for malignant arrhytmias in patients with known long QT syndrome and/or in thosewith severe left ventricular dysfunction, it seems prudent to consult the use of any antipsychoticdrug in cardiac patient with a cardiologist. On the other hand, no apparent benefit of routineECG monitoring prior and after antipsychotic drug administration in non-cardiac patient is to beanticipated. Last but not least, other adverse effects like orthostatic hypotension due to
-receptorsblockade, impairment of lipid or glucose metabolism, and/or unwanted weight gain shouldalso be considered when antipsychotic drugs are prescribed.

Key words:
atypical antipsychotic drugs, torsade de pointes, sudden death, QT interval.