Prolonged QTc intervals in medicated patients with schizophrenia

Abstract

Psychotropic drugs have been associated with sudden deaths and the lengthening of corrected-QT interval (QTc) on the electrocardiogram which may be a precursor of life-threatening arrhythmias as reported with some of these drugs. The objectives of this study were to measure the frequency of QTc lengthening in patients with schizophrenia receiving psychotropic drugs, and to assess whether QTc lengthening was associated with certain psychotropic drugs and other risk factors. One hundred and sixty three patients with schizophrenia (104 males and 59 females) were included in the study. Clinical and demographic data were collected from the case records. One hundred healthy volunteers were recruited to establish values for upper limits of normal for measurement of QTc interval and dispersion. Eleven (6.7%) of the patients had a prolonged QTc interval. The significant predictors obtained from a logistic regression modelling were chlorpromazine, flupenthixol decanoate and fluphenazine decanoate. Caution should be exercised and monitoring with ECG should be considered in patients prescribed chlorpromazine and depot antipsychotic medications even at recommended doses.

Sex difference in QTc prolongation in chronic institutionalized patients with schizophrenia on long-term treatment with typical and atypical antipsychotics

“…However, some studies reported no sex difference in QTc prolongation (Ozeki et al 2010). Other studies failed to detect female gender as a significant risk factor (Reilly et al 2000;Chong et al 2003;Rettenbacher et al 2005), or even QTc prolongation was found more commonly in male patients than in female patients (Ozeki et al 2010). Female gender is known to be a risk factor for QTc prolongation (Taylor 2003;Vieweg et al 2009).…”

Antipsychotic drugs and QT prolongation

“…On multiple regression analysis, age and dose of the antipsychotic drug were predictors for QT prolongation. A further study in 163 psychiatric inpatients (36% female, age 24-86 years) on antipsychotic drugs, with no indication of how QTc was calculated, found a QTc > 453 ms in 7% (Chong et al, 2003). Significant predictors for QT prolongation in a logistic regression model were the use of chlorpromazine, flupenthixol decanoate and fluphenazine decanoate.…”

“…Flupenthixol, a phenothiazine derivate, was identified as significant predictor for QT prolongation in a study in 163 psychiatric inpatients with no indication of how QTc was calculated (36% female, age 24-86 years) (Chong et al, 2003). No occurrence of TdP has been reported in association with this drug.…”

“…Fluphenazine, a phenothiazine derivate, was identified as significant predictor for QT prolongation in a study in 163 psychiatric inpatients with no indication of how QTc was calculated (36% female, age 24-86 years) (Chong et al, 2003). In 16 chronic schizophrenic patients on fluphenazine decanoate (proportion of females and age not given), ECG abnormalities occurred in 31%, one of them showing a QT prolongation > 400 ms (Turbott et al, 1987).…”

Physical illness and schizophrenia: a review of the literature

“…We included studies on cardiovascular comorbidity, which as a minimum criterion used a control group (9,59,(173)(174)(175)(176)(177)(178)(179)(180)(181)(182)(183)(184)(185)(186)(187)(188)(189)(190). Overall, these studies, some of which were population-based, showed that cardiovascular problems are more frequent among people with schizophrenia than in control populations, although in terms of specific disorders the overall picture was heterogeneous.…”