Natural Foods Merchandiser

Industry slams herb-drug interaction study

The natural products industry has criticized a new research review published in the Journal of the American College of Cardiology that warned of the dangerous interactions that some herbal supplements can cause in heart disease patients who take prescription drugs. The study was released on Monday.

“The errors and problems in this paper are too numerous to list completely at this time,” said Mark Blumenthal, founder and executive director of the Austin, Texas-based American Botanical Council. “While there are potential and actual interactions that various herbs can have with drugs used by patients with cardiovascular diseases, this paper will do little to improve professional awareness and skill in this area.”

In a press release, the American Botanical Council specified several errors in the published study:

  • Latin names for herbs are missing. For example, the authors don’t clarify the species of ginseng discussed. Many ginseng species “cause varying pharmacological effects,” noted Blumenthal in the release.

  • Some herbs labeled in the study as “commonly used” are not generally available in the U.S. dietary supplement market.

  • Capsicum is listed as being used for shingles, trigeminal, and diabetic neuralgia. But the over-the-counter and prescription drug capsaicin, a compound derived from chili peppers (Capsicum spp.), actually is used for those purposes.

“There are more [flaws],” said Blumenthal, adding that the study "should not have been published in its present form without serious additional edits, revisions and deletions, and the Journal of the American College of Cardiology would be advised to retract it."

The Washington, D.C.-based Natural Products Association also analyzed the research review, which called for drug-like oversight of herbal therapies. The NPA issued the following comment to NFM’s sister website NPIcenter: “The authors fail to understand that the risk needs to be attributed to the riskier product, which all would agree is the pharmaceutical. The risk they speak of, while nice in theory, in reality does not add up,” said Daniel Fabricant, PhD, vice president for scientific and regulatory affairs at the NPA.

The Washington, D.C.-based Council for Responsible Nutrition, a trade association representing dietary supplement manufacturers and ingredient suppliers, also questioned the accuracy of the study, noting in a press release that the "Dietary Supplement and Non-Prescription Drug Consumer Protection Act, passed in 2006, requires dietary supplement manufacturers to report any serious adverse events to the U.S. Food and Drug Administration. This post-market surveillance tool—in addition to the issuance in 2007 of newly updated Good Manufacturing Practices for all dietary supplements—greatly strengthened regulations for this industry.”

According to the CRN, during the first full year that the law requiring manufacturers to report serious adverse events was in effect, the FDA reported receiving 1,080 adverse event reports, only 672 of which were considered serious, for all dietary supplement products. For the same year, the FDA received more than 526,000 adverse event reports related to drugs and biologic products, more than 300,000 of which were considered serious, including close to 50,000 deaths, according to the CRN.

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