Electrocardiographic and hemodynamic effects of a multicomponent dietary supplement containing ephedra and caffeine: a randomized controlled trial.

Context: Metabolife 356, a multicomponent dietary supplement containing ephedra and caffeine (DSEC) in addition to several other components, is the top-selling dietary weight loss supplement. Given its common use, anecdotal reports of cardiovascular and cerebrovascular adverse events, and paucity of safety data, further research with this DSEC was warranted.

Objective: To determine the impact of the DSEC on corrected QT (QTc) interval duration and systolic blood pressure (SBP).