Prevalence of Prolonged QTC Interval in Patients Taking Psychopharmacs

Apart from providing knowledge on the beneficial effects of drugs, practical psychopharmacotherapy also includes drug profiles of adverse effects, especially when medical comorbidity is present. The mechanism of action of many psychotropic drugs, mainly antipsychotics and antidepressants, is associated with prolongation of the QT interval and the occurrence of arrhythmias, specifically Torsade de pointes (TdP), which can be lethal. The aim of this pilot study was to confirm the prevalence of prolonged QTc interval in a sample of psychiatric patients taking psychopharmacs.

The present study included 41 patients who were already on psychopharmacs. The average value of the QTc interval in the observed sample was 413.8±23.3 ms. The most frequent psychopharmacotherapy was the combination of typical and atypical antipsychotics (24.4%), followed by monotherapy with antipsychotics (22%) and combined antidepressant and atypical antipsychotic therapy (22%). The average value of the QTc interval for male patients was 412.1±25.2 ms, whereas for female patients, it was 416.6±20.4 ms. No difference between sexes was confirmed (p=0.555). The correlation between the QTc interval and age of patients was positive but not statistically significant (p=0.072). The highest average (419.3±31.6 ms) and highest maximum (479 ms) values of the QTc interval were noted for patients undergoing combined therapy of antidepressants and atypical antipsychotics. Prolonged values of the QTc interval were observed for seven males and one female, and no patients exhibited pathological values.

This study confirmed previous research that found that prolongation of the QTc interval exists in patients in sample groups who take psychopharm acs, but not up to critical values.