Potentially Arrhythmogenic Effects of Haloperidol and Olanzapine on Cardiac Autonomic Function-A Preliminary Study

Abstract

Objective: Antipsychotic medications have been linked to instances of cardio-toxicity or unexplained sudden death. Dysfunction of the cardiac autonomic nervous system may be attributable to the adverse arrhythmic effects in schizophrenic patients taking antipsychotics. Materials and Methods: Twelve schizophrenic patients with scores for the Brief Psychiatry Rating Scale of less than 40, including nine haloperidol-treated patients and three olanzapine-treated patients, were recruited from the outpatient clinic. Each patient received comprehensive measurements of cardiac autonomic nervous function changes at two time points. The first assessment was done after discontinuing the antipsychotics and anticholinergics for more than two weeks. These patients then were prescribed the antipsychotic at the previous dosage again after this first assessment. The second assessment was performed six weeks later. Results: Our study found no statistically significant differences in QTc prolongation between the nine haloperidol-treated and the three olanzapine-treated patients. None of the variables for cardiac autonomic nervous function predicted any arrythymogenic potential of the antipsychotics in our study. Conclusions: Autonomic nervous variables do not seem to be suitable indices for arrythmogenic potential in medicated schizophrenic patients. Future studies involving larger samples are needed to confirm these results.