Conference to examine effects of dietary supplements in patients taking blood thinning medications

01/10/05

Leading experts will discuss current knowledge, assess need for clinical guidelines

The National Heart, Lung, and Blood Institute will convene a conference this week to evaluate the risks of interactions between dietary supplements and prescription blood-thinning medications which are used by four million Americans to ward off heart attack or stroke. Experts from the National Institutes of Health and the Food and Drug Administration will join academic, patient advocacy and industry representatives to assess current knowledge, identify strategies for clinical guidelines, and determine opportunities for further research.

The NIH Conference on Dietary Supplements, Coagulation, and Antithrombotic Therapies will be held January 13 and 14, 2005, at the Masur Auditorium of the National Institutes of Health (NIH) in Bethesda, Maryland. It is sponsored by the National Heart, Lung, and Blood Institute (NHLBI), in collaboration with the Office of Dietary Supplements (ODS), the National Center for Complementary and Alternative Medicine (NCCAM), the NIH Clinical Center (CC), the National Institute of Neurological Disorders and Stroke (NINDS), the NIH Foundation, and the Office of Rare Diseases (ORD) at NIH.

"With up to 52 percent of the U.S. population reporting dietary supplement use, it is important that we fully understand how these substances can affect widely-used drugs, such as warfarin and aspirin," said NHLBI Acting Director Barbara Alving, M.D.

To date, there have been few systematic examinations of the effects of dietary supplements when taken with prescribed anti-thrombotic (anti-coagulant or anti-platelet) therapies. According to the Natural Medicines Comprehensive Database, approximately 180 dietary supplements have the potential to interact with warfarin, a common blood thinner, and more than 120 may interact with aspirin, and other anti-platelet agents such as clopidogrel, ticlopidine, and dipyridamole. Dietary supplements include herbal remedies, vitamins, minerals, other botanical products, fibers, amino acids, proteins, organ tissues, and metabolites for digestion.

Known interactions with prescribed anti-coagulants and their effects include:

  • Anise and Dong Quai have anti-coagulant effects;
  • Omega 3-fatty acids in fish oil, ajoene in garlic, ginger, Ginkgo, and vitamin E have anti-platelet properties;
  • Fucus and Danshen can have a heparin-like blood thinning effect;
  • St. John's Wort and American Ginseng alter drug metabolism; and
  • Other supplements, such as high dose vitamin E, Alfalfa, and Coenzyme Q10 may affect blood clotting.

"We plan to obtain a variety of perspectives on this issue so that we have a better understanding of managing patients' drug regimens," said Ahmed Hasan, M.D., Ph.D., medical officer with NHLBI's Division of Blood Diseases and Resources. "It is important to increase our knowledge on this issue so that we may better inform and educate our patients," he added.

Selected presentations:

  • New Tools and Methodologies for Research and Clinical Practice
    (Friday, January 14, 8:00 a.m.)
    This session will address methods and best practices for researching and monitoring interactions in patients using dietary supplements.

  • Panel of Experts: Opinions and Research Priorities
    (Friday, January 14, 10:30 a.m.)
    This multi-disciplinary panel will explore known drug and supplement interactions including anecdotal evidence, and develop an inventory of research needs.

  • Public Health Concerns: Facts, Fictions, and Gaps in Knowledge
    (Friday, January 14, 1 p.m.)
    This section will include presentations on the perspectives of academia, the FDA, and the dietary supplement industry to assess the need for clinical guidelines.

  • Dialogue with Patient Care Organizations
    (Friday, January 14, 2:45 p.m.)
    Speakers for this session include representatives from the Platelet Disorder Support Association, the National Consumers League, the American Medical Association, the American Society of Hematology, the American Heart Association, the American Herbal Products Association, the American Society of Clinical Nutrition, the American Dietetic Association, and the American Society of Health System Pharmacists.

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