Cardiovascular Dangers of Ma Huang
May 30, 2002
Cardiovascular Dangers of Ma Huang
Abstract & Commentary
Synopsis: This study concluded that ma huang use was temporally related to stroke, MI, and sudden death.
Source: Samenuk D, et al. Mayo Clin Proc. 2002;77:12-16.
Many forms of alternative medical therapy are currently available but there is little question that the herbal medicines contained in weight loss products are the most commonly purchased nutritional supplements with sales estimated at $3.6 billion in 1997.1 Ma huang is derived from the genus Ephedra and is a popular herb that is used in many nontraditional medications. Because it is a natural source of ephedrine, ma huang is commonly used for appetite suppression and energy enhancement.
Samenuk and associates from the Cardiac Arrhythmia Service of the New England Medical Center in Boston, Mass, evaluated the possible cardiovascular toxic effects associated with the use of dietary supplements containing ma huang. They reviewed the comprehensive Adverse Reactive Monitoring System database of the Food and Drug Administration that included the clinical records and the investigative and autopsy reports of patients who had used ma huang. The main outcome measures evaluated the occurrence of stroke, myocardial infarction (MI), and/or sudden death. They found that ma huang was temporally related to stroke in 16 patients, MI in 10, and sudden death in 11 of the 37 patients in the database. Autopsies performed on 7 of the 11 patients who died suddenly demonstrated a normal heart in 1, coronary atherosclerosis in 3, and cardiomyopathies in 3 other patients. In 36 of the 37 patients, the use of ma huang was reported to be within the manufacturers’ dosing guidelines. Samenuk et al concluded that ma huang use was temporally related to stroke, MI, and sudden death, that underlying cardiovascular disease was not a prerequisite for ma huang-related adverse events, and that the cardiovascular toxic effects associated with ma huang use were not limited to large or massive doses of the herb.
Comment by Harold L. Karpman, MD, FACC, FACP
Although rigorous standards of safety and efficacy of drugs usually have to be met through appropriately designed clinical trials before a drug is made available to the public, herbal remedies and dietary supplements are protected by the "Dietary Supplements Health and Education Act of 1994" and can be withdrawn from the market only if they are proven to be "unsafe," that is, if the marketed dietary supplement has been demonstrated to present a serious or unreasonable risk under the conditions of use recommended on the label or as commonly consumed.2 Because ma huang comes from a natural source of ephedrine, it is commonly found in weight loss and energy enhancement products. The common misconception that the substance has no associated serious medical consequences has contributed to the widespread use of the herb in many weight reduction products despite the fact that the potential cardiovascular toxic effects of ma huang had never previously been systemically evaluated.
Careful analysis of the medical records of 37 patients in the FDA Adverse Reaction Monitoring System database clearly demonstrated that the use of ma huang may be associated with serious cardiovascular and, possibly, other medical complications. It should be noted that a substantial portion of the patients studied were young, had no other risk factors for cardiovascular disease such as diabetes, hypertension, smoking, or family history of premature cardiovascular diseases, and their findings confirmed observations from other reports3-6 that ma huang may precipitate life-threatening events. This report is limited because it is an observational study and as such does not definitively establish the relationship between ma huang use and the risk of the reported adverse cardiovascular events. In addition, even though it provided no insight into the biological mechanisms believed the possible adverse effects of ma huang or the anorectic agents in which it is used, the reported observations should raise important public health issues that warrant further research.
The incidence of complications among the 12 million people in the United States who have consumed products containing ma huang in 1999 appeared to be extremely small, however, it should be recognized that the adverse effects of these drugs are usually under reported and, more important, the agent itself has never proven scientifically to be of benefit in weight reduction regimens. However, at this time, it would seem incumbent on any physician to advise his patients not to ingest herbal remedies or other forms of alternative medications which might contain ma huang and/or more concentrated ephedrine compounds because it has now been clearly suggested that ma huang usage may be associated with a higher incidence of sudden death, MI, and stroke even in the absence of structural heart disease.
Dr. Karpman, Clinical Professor of Medicine, UCLA School of Medicine, is Associate Editor of Internal Medicine Alert.
References
1. Canedy C. Real medicine or medicine show? Growth of herbal remedy sales raises issues about value. New York Times. July 23, 1998:DI.
2. Shifman NR, et al. N Engl J Med. 1998;339:806-811.
3. Haller CA, Benowitz NL. N Engl J Med. 2000;343: 1833-1838.
4. Zahn KA, Li RL, Purssell RA. J Emerg Med. 1999; 17:289-291.
5. Zaacks SM, et al. J Toxicol Clin Toxiol. 1999;37: 485-489.
6. Theoharides TC. J Clin Pyschopharmacol. 1997;17: 437-439.
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