Sun, Nov 02, 2003 - Page 2 News List

Doctors warn against common plant extract


Stricter medical safety laws should be established to regulate the use of aristolochic acid, a plant extract commonly used in traditional Chinese medicine, according to doctors concerned about its confirmed carcinogenic effects.

"The World Health Organiza-tion's International Agency for Research on Cancer (IARC) has already identified aristolochic acid as a carcinogenic agent, but in Taiwan we have no laws regulating its use," Deng Jou-fang (鄧昭芳), president of the Taiwan International Medical Alliance, said at the annual Workshop on Herbal Medicine Poisoning yesterday.

Deng said that many nations, including Belgium, France, Britain, Canada, the US, Spain, Australia, Germany, Egypt, Malaysia and the Philippines, have already banned the agent. Singapore prohibits the use of aristolochic acid for more than two weeks, and China has banned Aristolochia manshurien-sis, a popular herb containing aristolochic acid.

"Despite international studies proving that the acid will lead to cancer and kidney failure, Taiwan has thus far only issued an ambiguous warning cautioning the public against the use of aristolochic acid in high dosages and for prolonged periods of time. What's more, the warning only mentions kidney impairment, never informing consumers of the possibility of cancer," Deng said.

Heinz Schmeiser, a doctor at the German Cancer Research Center, agreed with Deng. He said his research indicated that the acid was a potent carcinogen.

"Aristolochic acid will cause the formation of a DNA adduct, a chemical bond between the agent and a person's DNA. Mutations to this adduct will lead to cancer," Schmeiser said.

He referred to an incident in Brussels in which a group of women had mistakenly taken aristolochic acid instead of another drug. According to Schmeiser, follow-up studies indicated that within two to three years, all of the women had been diagnosed with kidney function impairment.

"About half of the women were diagnosed with cancer within five to six years. We've found cancer in animals about 24 hours after exposure," Schmeiser said.

However, traditional Chinese doctors stood up for the benefits of the drug yesterday, saying that many Western drugs were exempt from similar restrictions, despite having clear negative side-effects.

Lin I-hsing (林宜信), chairman of the Department of Health's Committee on Chinese Medicine and Pharmacy, said that the appropriate use of a drug depended on finding a balance between the risks and benefits involved.

"In a crisis situation it might be an option to use the acid for a week, even if it will result in harming one's kidneys. It all depends on evaluating the benefits of the drug in a specific situation," said Hsieh Yen-yau (謝炎堯) of the Koo Foundation Sun Yat-sen Cancer Center.

Hsieh said that aristolochic acid could be easily replaced with safer drugs, eliminating the need for the drug altogether.

Lin explained that the DOH is planning to conduct a comprehensive investigation of policies regulating Chinese medicine next year. He said new policies regulating imported Chinese drugs would be implemented soon. The DOH is working directly with drug safety organizations in other nations on this matter.

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