By Pal Pacher and Valeria Kecskemeti

Abstract

The cardiovascular toxicity of older generation of tricyclic antidepressants (e.g. imipramine, desipramine, amitriptyline, clomipramine) and neuroleptics (e.g. haloperidol, droperidol, thioridazine, pimozide) is well established. These drugs inhibit cardiovascular Na+, Ca2+ and K+ channels often leading to life-threatening arrhythmia.

To overcome the toxicity of old generation of antidepressants and antipsychotics, selective serotonin reuptake inhibitor antidepressants (SSRIs: fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxin) and several new antipsychotics (e.g. clozapine, olanzapine, risperidone, sertindole, aripiprazole, ziprasidone, quetiapine) were introduced during the past decade. Although these new compounds are not more effective in treating psychiatric disorders than older medications, they gained incredible popularity since they have been reported to have fewer and more benign side effect profile (including cardiovascular) than predecessors.

Surprisingly, an increasing number of case reports have demonstrated that the use of SSRIs and new antipsychotics (e.g. clozapine, olanzapine, risperidone, sertindole, aripiprazole, ziprasidone, quetiapine) is associated with cases of arrhythmias, prolonged QTc interval on electrocardiogram (ECG) and orthostatic hypotension in patients lacking cardiovascular disorders, raising new concerns about the putative cardiovascular safety of these compounds. In agreement with these clinical reports these new compounds indeed show marked cardiovascular depressant effects in different mammalian and human cardiovascular preparations by inhibiting cardiac and vascular Na+, Ca2+ and K+ channels. Taken together, these results suggest that the new generation of antidepressants and antipsychotics also have clinically important cardiac as well as vascular effects. Clinicians should be more vigilant about these potential adverse reactions and ECG control may be suggested during therapy, especially in patients with cardiovascular disorders.

The primary goal of this review is to shed light on the recently observed clinically important cardiovascular effects of new antidepressants and antipsychotics and discuss the mechanism beyond this phenomenon.

Keywords: antidepressants, neuroleptics, antipsychotics, QT prolongation, arrhythmia, cardiac ion channels, repolarization.

Introduction

Cardiovascular mortality in psychiatric patients is high. Reports of sudden unexplained death in those taking psychotropic drugs, including neuroleptics and antidepressants, have raised the concern that part of this excess may be due to drug-induced arrhythmias, since many of these drugs have cardiac electrophysiological effects similar to those of quinidine. Indeed, it has recently been established that old generation of antidepressants (tricyclic antidepressants (TCAs) and antipsychotics (e.g. haloperidol, droperidol, thioridazine, pimozide) can be associated with increased risk of cardiac arrhythmias and sudden death [reviewed in 1–7].

In contrast, new generation of selective serotonin reuptake inhibitor antidepressants (SSRIs: fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxin) and several new antipsychotics (e.g. clozapine, olanzapine, risperidone, sertindole, aripiprazole, ziprasidone, quetiapine risperidal) are considered to be free from the cardiotoxicity of their predecessors. However, there are increasing number of case reports on various arrhythmias and syncope associated with the use of these new compounds [reviewed in: 3, 5–9]. In addition recent studies have demonstrated that the new SSRIs and antipsychotics also exert potent cardiovascular depressant effects in various mammalian and human cardiovascular preparations by inhibiting cardiac and vascular Na+, Ca2+ and K+ channels. This review is concerned with the cardiovascular effects of new antidepressants and antipsychotics.

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