Effect of Enzyte on QT and QTc Intervals | Cardiology | JAMA Internal Medicine | JAMA Network
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Research Letter
August 9/23, 2010

Effect of Enzyte on QT and QTc Intervals

Author Affiliations

Author Affiliations: Chicago College of Osteopathic Medicine, Chicago College of Pharmacy Midwestern University, Downers Grove, Illinois (Drs Phillips, Sullivan, Snyder, and Allegretti); and Marcella Niehoff School of Nursing and Stritch School of Medicine, Loyola University Chicago (Dr McBride).

Arch Intern Med. 2010;170(15):1402-1404. doi:10.1001/archinternmed.2010.254

Dietary supplements represent a distinct class of biologically active compounds which, unlike prescription and over-the-counter products, have been available to the public without regulatory oversight for nearly 15 years and are responsible for more than 13 000 adverse events annually.1,2 Like many dietary supplements, Enzyte (Vianda, Cincinnati, Ohio)—a dietary supplement marketed for “male enhancement,” a euphemism for erectile dysfunction—is a multicomponent preparation marketed to consumers without stringent regulatory oversight or premarketing evaluation of pharmacokinetics, pharmacodynamic, or drug interaction studies, including thorough QT and corrected QT (QTc) studies to assess proarrhythmic risk. Considering this information, we conducted a randomized, double-blind, double-dummy, placebo-controlled, dose-ranging, crossover study of the effects of Enzyte on the electrocardiographic (ECG) parameters including the QTc interval.