Herbal products containing aristolochic acids have been linked to reports of kidney failure and will be the subject of an import alert in the near future, FDA says in a May 16 letter to industry.

The agency notified six trade associations representing dietary supplement companies that products containing aristolochic acids have caused "several life-threatening adverse incidents," most frequently in the form of "severe nephropathy," a kidney disorder.

Attached to the letter is a list of approximately 50 plants containing aristolochic acids of which supplement firms should be wary. However, FDA notes the list is not comprehensive, as the Aristolochia family contains "about 600 species."

The agency action follows public warnings issued by Health Canada and the Medicine Controls Agency of the U.K. The MCA has issued a ban on the import and sale of Aristolochia through June 30, 2001. Last summer, two British women ages 49 and 57 were prescribed kidney transplants after ingesting the substance; the incident was reported in the Lancet. Roughly eight years ago, over 100 Belgian residents suffered severe kidney problems after taking a Chinese herbal remedy containing aristolochic acids.

The ingredient most likely is mistaken for a similar plant in the Stephania family often found in traditional Chinese preparations used as antirheumatics and diuretics. Typically, between 6 g and 12 g of the herb is boiled in water and then drank.

Although no adverse events have been reported in the U.S., FDA says in a May 24 "Dear Colleagues" letter that since "there is evidence that aristolochic acid-containing products are in international commerce," the agency will issue an import alert providing for "the automatic detention of dietary supplements or other products containing certain botanicals that may be adulterated with aristolochic acid."

The American Herbal Products Association and the Council for Responsible Nutrition notified member companies of FDA's actions in a joint memo May 25. AHPA commended the agency's response and noted in August 1999 it had asked its members to take measures to distinguish plants in the Aristolochia family from similar species. The association, along with CRN, is developing tests to differentiate the botanicals.

Aristolochic Acids Kidney AEs Subject Of Pending FDA Import Alert

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