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The New England Journal of Medicine -- September 17, 1998 --
Vol. 339, No. 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. (1,2) Some have caused serious illness in unsuspecting consumers. (3,4)
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
References
1. Huang WF, Wen KC, Hsiao ML. Adulteration by synthetic
therapeutic substances of traditional Chinese medicines in Taiwan. J
Clin Pharmacol 1997;37:344-50.
2. Espinoza EO, Mann M-J, Bleasdell B. Arsenic and mercury
in traditional Chinese herbal balls. N Engl J Med 1995;333:803-4.
3. Gertner E, Marshall PS, Filandrinos D, Potek AS, Smith
TM. Complications resulting from the use of Chinese herbal medications containing
undeclared prescription drugs. Arthritis
Rheum 1995;38:614-7.
4. Kang-Yum E, Oransky SH. Chinese patent medicine as a
potential source of mercury poisoning. Vet
Hum Toxicol 1992;34:235-8.
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