AJM theme issue: Obesity and diabetesClinical research studyHemodynamic effects of ephedra-free weight-loss supplements in humans
Section snippets
Clinical study
This was a randomized, double-blind, 3-arm crossover study involving 10 healthy adults aged 18 to 49 years. All volunteers gave written informed consent before study participation. The Committee on Human Research at the University of California, San Francisco (UCSF) approved the study protocol. Subject eligibility was determined by medical history, physical examination, and screening laboratory tests that included complete blood count, serum chemistry tests, urine toxicology testing for illicit
Results
Five men and five women aged 19 to 42 years (mean 27 years) were enrolled and all subjects completed the study. No adverse events occurred. Subjects ranged in weight from 51.2 to 84.7 kg (mean 70.3 kg). The race/ethnicity of the subjects were white (4), African-American (2), Hispanic (2), and Asian/Pacific Islander (2).
The mean plasma concentrations of synephrine over time after dosing with Xenadrine EFX and Advantra Z are shown in Figure 1, and the pharmacokinetic parameters for synephrine are
Discussion
In this study, we present novel data on the disposition characteristics and effects of synephrine taken orally as C. aurantium. We demonstrate for the first time that some ephedra-free weight-loss dietary supplements raise blood pressure in healthy, normotensive adults. These findings indicate that re-formulated weight loss supplements have similar acute cardiovascular stimulant actions as banned ephedra products and could cause adverse health effects in some individuals.
From the plasma
Acknowledgments
This work was funded by Public Health Service grants K23AT00069-04 (National Center for Complementary and Alternative Medicine), DA12393, and a General Clinical Research Center Award (M01RR00083-41). We are grateful to Minjing Duan for his analytical chemistry work, Gina Lowry and Mary Kay Pederson for subject recruitment and assistance with the clinical study, Faith Allen for oversight of protocol development and data management, Dr. Peter Bacchetti and Dr. Alan Bostrom for statistical
References (20)
- et al.
Adverse cardiovascular events temporally associated with ma huang, an herbal source of ephedrine
Mayo Clin Proc
(2002) - et al.
Exercise-induced syncope associated with QT prolongation and ephedra-free Xenadrine
Mayo Clinic Proc
(2004) - et al.
Effects of Citrus aurantium extract, caffeine, and St. John’s wort on body fat loss, lipid levels, and mood states in overweight healthy adults
Curr Ther Res
(1999) - et al.
Antiobesity and cardiovascular toxic effects of Citrus aurantium extracts in the rata preliminary report
Fitoterapia
(1999) US Food and Drug Administration. Questions and answers about FDA’s actions on dietary supplements containing ephedrine alkaloids
(2004)- et al.
Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance
JAMA
(2003) - et al.
Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids
N Engl J Med
(2000) - et al.
Citrus aurantium, an ingredient of dietary supplements marketed for weight losscurrent status of clinical and basic research
Exp Biol Med
(2004) - et al.
Elusive amines and primary headacheshistorical background and prospectives
Neurol Sci
(2003) - et al.
Activities of octopamine and synephrine stereoisomers on α-adrenoceptors
Br J Pharmacol
(1988)
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Drs. Haller and Benowitz have served as paid expert witnesses in litigation involving manufacturers of dietary supplements.