Energy Drinks Tied to QTc Prolongation

By Kelly Young

Edited by David G. Fairchild, MD, MPH, and Lorenzo Di Francesco, MD, FACP, FHM

Consuming caffeinated energy drinks is associated with QTc interval prolongation, which is a risk factor for torsades de pointes, according to a small study in the Journal of the American Heart Association.

Thirty-four healthy adults aged 18 to 40 were assigned to consume two different commercially available energy drinks and a placebo drink. Participants drank each 32-oz beverage over 60 minutes on 3 separate days, in randomized order. The energy drinks contained over 300 mg of caffeine, plus taurine, glucuronolactone, vitamins, and proprietary ingredients. Participants were monitored by electrocardiogram over 4 hours.

The maximum placebo-adjusted increase in QTc was 6.1 ms and 7.7 ms for each energy drink. In addition, systolic blood pressure was about 5 mm Hg higher after energy drink versus placebo consumption.

The authors conclude: "Individuals with acquired or congenital long QT syndrome and those with hypertension should be more vigilant and limit their energy drink intake. Based on currently available data, the class of energy drinks, rather than one particular product, warrants use with caution."