McBride Brian F, Karapanos Angeliki K, Krudysz Agnes, Kluger Jeffrey, Coleman Craig I, White C Michael
University of Connecticut Schools of Pharmacy, Storrs, Conn, USA.
JAMA. 2004 Jan 14;291(2):216-21. doi: 10.1001/jama.291.2.216.
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.
To determine the impact of the DSEC on corrected QT (QTc) interval duration and systolic blood pressure (SBP).
Randomized, double-blind, placebo-controlled, crossover study conducted from January to May 2003.
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.
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.
Maximal QTc interval and SBP assessed at 1, 3, and 5 hours after dosing for the DSEC relative to placebo.
Individuals receiving the DSEC had a longer maximal QTc interval (mean [SD], 419.4 [11.8] vs 396.1 [15.7] milliseconds; P<.001) and higher SBP (mean [SD], 123.5 [10.98] vs 118.93 [9.62] mm Hg; P =.009) compared with placebo. Participants who received the DSEC were more likely to experience a QTc interval increase of at least 30 milliseconds vs placebo (8 individuals [53.3%] vs 1 individual [6.7%]; relative risk, 2.67 [95% confidence interval, 1.40-5.10]). There were no significant sex-related differences.
The ephedra- and caffeine-containing dietary supplement Metabolife 356 increased the mean maximal QTc interval and SBP. Since the actual ingredient or ingredients in Metabolife 356 responsible for these findings are not known, patients should be instructed to avoid this and similar dietary supplements until more information is known about their safety.
Metabolife 356是一种多成分膳食补充剂，除了其他几种成分外，还含有麻黄和咖啡因（含麻黄碱和咖啡因的膳食补充剂），是最畅销的膳食减肥补充剂。鉴于其广泛使用、关于心血管和脑血管不良事件的传闻报告以及安全数据的匮乏，有必要对这种含麻黄碱和咖啡因的膳食补充剂进行进一步研究。
确定含麻黄碱和咖啡因的膳食补充剂对校正QT（QTc）间期时长和收缩压（SBP）的影响。
2003年1月至5月进行的随机、双盲、安慰剂对照、交叉研究。
从康涅狄格大学斯托尔斯校区招募了15名健康志愿者（平均[标准差]年龄，26.7[2.52]岁；体重，72.7[14.93]千克），其中6名（40%）为女性。
以交叉方式给予单剂量的含麻黄碱和咖啡因的膳食补充剂（含19种成分，包括麻黄[12毫克]和咖啡因[40毫克]）或匹配的安慰剂，治疗之间有7天的洗脱期。
相对于安慰剂，在服用含麻黄碱和咖啡因的膳食补充剂后1、3和5小时评估最大QTc间期和SBP。
与安慰剂相比，接受含麻黄碱和咖啡因的膳食补充剂的个体最大QTc间期更长（平均[标准差]，419.4[11.8]对396.1[15.7]毫秒；P<.001），SBP更高（平均[标准差]，123.5[10.98]对118.93[9.62]毫米汞柱；P =.009）。接受含麻黄碱和咖啡因的膳食补充剂的参与者比接受安慰剂的参与者更有可能经历QTc间期至少增加30毫秒（8人[53.3%]对1人[6.7%]；相对风险，2.67[95%置信区间，1.40 - 5.10]）。没有显著的性别差异。
含麻黄和咖啡因的膳食补充剂Metabolife 356增加了平均最大QTc间期和SBP。由于尚不清楚Metabolife 356中导致这些结果的实际成分，在更多关于其安全性的信息知晓之前，应指导患者避免使用这种及类似的膳食补充剂。
