First-generation antipsychotics and QTc: any role for mediating variables?

Objective Corrected QT (QTc) interval prolongation is often associated with use of first‐generation antipsychotics (FGAs). However, other factors require appropriate consideration, including age and gender, the role of other known medications associated with QTc prolongation, and severe comorbid conditions, such as co‐occurring alcohol abuse/dependence. We aimed to study potential mediating roles of different, related, candidate variables on QTc. Methods We capitalized on data from a large (N = 2366), cross‐sectional, national survey, the STAR Network QTc study, using a representative sample of people taking FGAs, and recruited from mental health services across Italy. Results About one‐third of the sample was treated with FGAs, and almost one‐tenth of the subjects took a different, additional, drug known to cause QTc prolongation. Our findings confirmed that there is an impact from FGAs, age, gender, alcohol misuse, and concurrent risky drugs on QTc. However, comorbid alcohol abuse/dependence and concurrent risky drugs did not mediate the effect of FGAs on QTc. Conclusions Our findings showed that FGAs, concurrent risky drugs, and alcohol use disorders prolonged QTc. FGAs had a direct effect on QTc, confirming the need for clinicians to monitor a risk that could lead to sudden unexplained death. Copyright © 2016 John Wiley & Sons, Ltd.