First, FDA advises manufacturers to review their current manufacturing practices. Their manufacturing practices should include procedures that ensure comprehensive and rigorous testing of ingredients and finished products to prevent the sale to consumers of products that contain potentially harmful impurities. At a minimum, we believe that it is absolutely necessary that manufacturers who produce products that contain ingredients that may be contaminated with aristolochic acid test their products to confirm the absence of aristolochic acids. Second, FDA believes that manufacturers need to take adequate steps to identify and report adverse events, especially adverse events that may include renal system disorders, associated with any product that contains an ingredient on the enclosed list of ingredients. Regardless of the reason for the presence of aristolochic acid in different products, it is important that products that contain aristolochic acid not be allowed to enter the U.S. marketplace.
Aristolochic acid is a potent carcinogen and nephrotoxin.
While a product that contains a large amount of it may result in the rapid onset of acute toxicity symptoms in a consumer using the product, a product containing a small amount could be used for years with no apparent adverse effects, until serious, irreversible effects, such as renal failure, has occurred. Because many of the products that are, or that contain, plants that contain aristolochic acids or that may be inadvertently contaminated with an Aristolochia spp. are imported into the United States, FDA has issued an import alert that provides for the automatic detention without physical examination of any product containing a plant listed in the enclosure to this letter. Detained product will be released when the responsible party can provide direct analytical evidence that it is free of aristolochic acid. FDA considers any FDA-regulated product containing any aristolochic acid to be unsafe and to be adulterated under the Act. FDA is available and prepared to assist the industry on these matters.