Résumé :
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[BDSP. Notice produite par INIST-CNRS RUop9R0x. Diffusion soumise à autorisation]. 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). Design : Randomized, double-blind, placebo-controlled, crossover study conducted from January to May 2003. Setting and Participants : Fifteen healthy volunteers (mean [SD] age, 26.7 [2.52] years ; weight, 72.7 [14.93] kg), 6 (40%) of whom were women, recruited from the University of Connecticut, Storrs campus. Intervention A single dose of the DSEC (containing 19 ingredients including ephedra [12 mg] and caffeine [40 mg]) or matching placebo were administered in a crossover fashion with a 7-day washout period between treatments. Main Outcome Measures : Maximal QTc interval and SBP assessed at 1,3, and 5 hours after dosing for the DSEC relative to placebo. Results : Individuals receiving the DSEC had a longer maximal QTc interval (mean [SD], 419.4 [11.8] vs 396.1 [15.7] milliseconds ; P<. and higher sbp vs mm hg p="009)" compared with placebo. participants who received the dsec were more likely to experience a qtc interval increase of at least milliseconds placebo individuals individual relative risk confidence there no significant sex-related differences. conclusions : ephedra-and caffeine-containing dietary supplement metabolife increased mean maximal sbp. since actual ingredient or ingredients in responsible for these findings are not known patients should be instructed avoid this similar supplements until information is about their safety.>
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