The New England Journal of Medicine -- September 17, 1998 -- Volume 339, Number 12
To the Editor:
Asian patent medicines are one component of what are called traditional Chinese medicines. Asian patent medicines comprise multiple products, including herbs, plants, animal parts, and minerals, which are formulated into tablets, pills, or liquids for ease of use. They are widely available in herbal stores and have gained acceptance by the American public as a form of alternative medicine. However, many patent medicines manufactured in Asian countries contain toxic ingredients, such as heavy metals, as well as prescription drugs or unapproved ingredients that may or may not be identified on the label. Some have caused serious illness in unsuspecting consumers.
The California Department of Health Services, Food and Drug Branch, initiated a study to screen imported Asian patent medicines for undeclared pharmaceuticals and heavy-metal contamination, using gas chromatography-mass spectrometry and atomic-absorption methods. Our objectives were to establish a computer data base for these products; educate the public, the herbal industry, and the medical community about the potential danger of Asian patent medicines; and provide objective information about toxicity.
Of 260 Asian patent medicines that have been collected from California retail herbal stores, 14 had labels that declared pharmaceutical ingredients, and 3 had insufficient sample amounts. Of the remaining 243 products, 17 (7 percent) contained undeclared pharmaceuticals. The most common undeclared ingredients were ephedrine, chlorpheniramine, methyltestosterone, and phenacetin. A total of 251 products were analyzed for lead, arsenic, and mercury; 9 other samples, including the 3 noted above, were insufficient for this analysis. Twenty-four products contained lead in a quantity of at least 10 parts per million (ppm) (range, 10 to 319; median, 29.8; mean, 54.9). Thirty-six products contained arsenic (range, 20.4 to 114,000 ppm; median, 180.5; mean, 14,553). Thirty-five products contained mercury (range, 22.4 to 5070 ppm; median, 329; mean, 1046); 2 of the 35 had labels that identified only pharmaceutical ingredients. The United States Pharmacopoeia limits heavy metals in most oral pharmaceuticals to 30 ppm, with lower limits for lead, arsenic, and mercury.
Of the 260 products we investigated, at least 83 (32 percent) contained undeclared pharmaceuticals or heavy metals, and 23 had more than one adulterant. The remaining products, which contained no detectable adulterants, cannot be assumed to be safe and free of toxic ingredients, in view of their batch-to-batch inconsistency, as well as limitations in our detection methods.
Richard J. Ko, Pharm.D., Ph.D.
California Department of Health Services
Sacramento, CA 94234-7320