The Effect of PsychotropicMedications and Their Combinations on theQTc Interval Among Jordanian Outpatients:A Cross-Sectional Study

Abstract

Objective: To investigate the effect of psychotropic drugs and their combinations on theQTc interval as well as the prevalence of long QTc (LQTc) among ambulatory patients withpsychiatric illness in Jordan. Methods: A cross-sectional study that included patients treated in an outpatient psychiat ric clinic was conducted. The QTc duration was calculated using a combined QT correction(Bazett’s formula for heart rate 60-100 and the Framingham formula for extremes of HR). Results: Among 307 patients, about 60% received multiple psychotropic drugs. TheLQTc frequency was 1.2%. QTc interval prolongation was observed in patients receivingselective serotonin reuptake inhibitors (SSRIs) (P = .011), tricyclic antidepressants (TCAs)(P = .033), citalopram (P = .044), or psychotropic polytherapy (P = .005). The additionof SSRIs to second-generation antipsychotics (SGAs) also lengthened the QTc interval(P = .029). There was a correlation between the number of psychotropic medications andthe QTc length (P = .018). All patients with LQTc carried at least one risk factor for it otherthan the use of psychotropic medication(s), 3 of 4 patients had a combination therapy, allpatients were prescribed SSRIs, and 2 of them had comorbid conditions.Conclusion: There is a high prevalence of psychotropic drugs polytherapy, and it is clearlyassociated with LQTc. Citalopram, SSRIs, and TCAs prolong QTc interval. It is recommendedto assess non-pharmacological factors for LQTc and, if necessary, to obtain an electro cardiogram before starting patients on psychotropic drugs known to prolong the QTcinterval.