Haller Christine A, Jacob Peyton, Benowitz Neal L
Division of Clinical Pharmacology, San Francisco General Hospital, University of California, 94143, USA.
Clin Pharmacol Ther. 2002 Jun;71(6):421-32. doi: 10.1067/mcp.2002.124523.
Serious cardiovascular toxicity has been reported in people taking dietary supplements that contain ma huang (Ephedra) and guarana (caffeine). We assessed the pharmacokinetics and pharmacodynamics of a dietary supplement that contains these herbal stimulants.
Eight healthy adults received a single oral dose of a thermogenic dietary supplement labeled to contain 20 mg ephedrine alkaloids and 200 mg caffeine after an overnight fast. Serial plasma and urine samples were analyzed by use of liquid chromatography-tandem mass spectrometry for ephedrine alkaloid and caffeine concentrations, and heart rate and blood pressure were monitored for 14 hours.
Plasma clearance and elimination half-lives for ephedrine, pseudoephedrine, and caffeine were comparable to published values reported for drug formulations. A prolonged half-life of ephedrine and pseudoephedrine was observed in 1 subject with the highest urine pH. Mean systolic blood pressure increased significantly to a maximum of 14 mm Hg above baseline at 90 minutes after ingestion (P <.001). There was a lag in the mean heart rate response that reached a maximum change of 15 beats/min above baseline at 6 hours after ingestion (P <.001). Diastolic blood pressure changes were insignificant. Two subjects who were taking oral contraceptives had longer caffeine half-lives (15.5 +/- 0.3 hours versus 5.6 +/- 1.7 hours) and lower values for oral clearance (0.34 +/- 0.01 mL/min. kg versus 0.99 +/- 0.41 mL/min. kg) than subjects who were not taking oral contraceptives.
Botanical stimulants have disposition characteristics similar to their pharmaceutical counterparts, and they can produce significant cardiovascular responses after a single dose.
据报道，服用含有麻黄（麻黄属植物）和瓜拉那（咖啡因）的膳食补充剂的人群中出现了严重的心血管毒性。我们评估了一种含有这些草药兴奋剂的膳食补充剂的药代动力学和药效学。
8名健康成年人在禁食过夜后口服单剂量的一种产热膳食补充剂，该补充剂标明含有20毫克麻黄碱生物碱和200毫克咖啡因。采用液相色谱 - 串联质谱法分析系列血浆和尿液样本中的麻黄碱生物碱和咖啡因浓度，并监测心率和血压14小时。
麻黄碱、伪麻黄碱和咖啡因的血浆清除率和消除半衰期与已发表的药物制剂报告值相当。在1名尿液pH值最高的受试者中观察到麻黄碱和伪麻黄碱的半衰期延长。摄入后90分钟时，平均收缩压显著升高，最高比基线升高14毫米汞柱（P <.001）。平均心率反应有延迟，摄入后6小时达到最大变化，比基线高15次/分钟（P <.001）。舒张压变化不显著。与未服用口服避孕药的受试者相比，两名服用口服避孕药的受试者咖啡因半衰期更长（15.5±0.3小时对5.6±1.7小时），口服清除率更低（0.34±0.01毫升/分钟·千克对0.99±0.41毫升/分钟·千克）。
植物兴奋剂的处置特征与其药物对应物相似，单次给药后可产生显著的心血管反应。
