Drug interactions and creatinine levels are associated with QTc prolongation in intensive care units: a prospective, observational study.

Abstract

Background Prolongation of the QTc interval may lead to life threatening arrhythmias. QTc prolongation is common in intensive care unit (ICU) patients. The objectives of this study were to identify the role of drug-drug interactions (DDIs) and other predictors (age, sex, cardiovascular diseases, and electrolyte abnormalities) in life threatening QTc prolongation in patients admitted to medical (M), surgical (S) and emergency (E) ICUs. Methods This prospective, observational study included patients above the age of 18 years who were admitted to SICU, EICU, and MICU at a tertiary respiratory referral center. Electrocardiogram (ECG) monitoring was performed during the first 5 days of ICU admission. Risk factors and DDIs which were anticipated to be associated with the prolongation of the QTc interval were assessed for all patients. Results Two hundred patients were included in the study. QTc prolongation occurred in 10.7% of patients and the majority of patients presenting with QTc prolongation had creatinine levels above 1.3 mg/dL during their 5 days of ICU admission. Incidence of pharmacodynamic (PD) DDIs was significantly higher in patients with QTc prolongation vs. other patients. Creatinine levels above 1.3 mg/dL and PD DDIs were associated with QTc prolongation during 5 days of ICU admission. Conclusions High serum creatinine and PD DDIs can increase the risk of QTc prolongation in patients admitted to the ICU. QTc interval measurements should be performed prior to initiation or after starting any drug that is associated with QT prolongation, specifically in patients with the known risk factors.