RESUMEN
STUDY OBJECTIVE: To determine the effect of an ephedra-containing thermogenic herbal compound (TrimSpa) on rate-corrected QT (QTc) interval duration and systolic blood pressure. DESIGN: Randomized, double-blind, placebo-controlled, crossover, intent-to-treat study. SETTING: Student laboratory at a college of pharmacy. SUBJECTS: Thirteen healthy volunteers (eight men, five women). INTERVENTION: Participants were given TrimSpa, which contains more than 30 ingredients including ephedra 15 mg and caffeine 60 mg, or matching placebo 3 times/day for 7 days in a crossover fashion with a 7-day washout period between treatments. MEASUREMENTS AND MAIN RESULTS: Each subject's QTc interval and systolic blood pressure were measured on days 1, 4, and 7. These measurements were performed immediately before study drug ingestion (baseline) and 0.5, 1, and 3 hours after ingestion. No differences in these variables were found between the TrimSpa and placebo groups. In one subject taking TrimSpa, the QTc interval increased 96 msec from baseline, more than double the largest increase in the placebo group. CONCLUSION: Standard doses of TrimSpa did not induce changes in subjects' QTc intervals or systolic blood pressures. However, because the QTc interval dramatically changed in one subject taking TrimSpa, a large study is needed to determine if the effect is an artifact or if the subject represents a subset of people for whom the drug may pose a risk.