Evaluation of the Effects of Quetiapine on QTc Prolongation in Critically Ill Patients

Quetiapine, an atypical antipsychotic used in the intensive care unit (ICU) to manage delirium, has a possible adverse effect of corrected QT (QTc) interval prolongation. The objective of this analysis was to describe the impact of quetiapine on QTc interval prolongation in critically ill patients. This was a single-center, prospective cohort analysis of ICU patients who received quetiapine between October 2015 and February 2016. The major end point was the incidence of QTc prolongation greater than 60 milliseconds above baseline during therapy. Minor end points included median change in QTc interval and incidence of Torsades de Pointes (TdP). Univariate and multivariable analyses were performed to determine variables associated with higher risk of QTc prolongation. During the study period, 103 patients were enrolled in the analysis. QTc interval prolongation greater than 60 milliseconds occurred in 14 (13.6%) patients. The median change in QTc interval was 20 milliseconds. There were no cases of TdP. On multivariable analysis, the only variable associated with higher incidence of QTc prolongation was administration of a concomitant medication known to prolong the QTc interval ( P = .046). QTc prolongation was relatively uncommon among critically ill patients utilizing quetiapine. Patients receiving concomitant medications known to prolong the QTc interval may be at an increased risk.