Prolonged QTc intervals in medicated patients with schizophrenia

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.