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An NIH Conference on Dietary Supplements, Coagulation,
and Antithrombotic Therapies
Executive Summary

Conference Home

Executive Summary







Continuing Education


On January 13th and 14th, 2005, the National Institutes of Health (NIH) held a conference on dietary supplements, coagulation, and antithrombotic therapies in Masur Auditorium, NIH in Bethesda, Maryland. The broad interest in this subject was reflected by the number of co-sponsors and the scope of their collective missions: the National Heart, Lung, and Blood Institute (NHLBI), the Office of Dietary Supplements (ODS), the NIH Clinical Center (CC), the National Center for Complementary and Alternative Medicine (NCCAM), the National Institute for Neurological Disorders and Stroke (NINDS), the Office of Rare Diseases (ORD), and the Foundation for the National Institutes of Health (FNIH).

Approximately 4 billion people around the world use some form of dietary supplement to enhance their nutritional intake and/or treat disease in conjunction with medical therapies, such as antithrombotic agents, without their healthcare providers’ knowledge. Greater acceptance and informed management of these complicating factors, better knowledge about the likelihood for dietary supplement-drug interactions, and better methods for obtaining and disseminating this information could only lead to improved patient safety and management.

The goal of the two-day meeting was to gain greater understanding of the complex issues of dietary-supplement use by patients undergoing antithrombotic therapies. To achieve this, the organizers brought scientific and medical expertise together with interested parties from academia, industry, patient-advocacy groups, and government regulatory agencies.

The conference organizers and attendees took a critical scientific look at how dietary supplements affect the human body's normal clotting response and the antithrombotic therapies (anticoagulant and antiplatelet agents) commonly used to treat and prevent thrombosis. Additional objectives included the development of strategies to raise awareness among patients and practitioners about the use of dietary supplements, to formulate a framework for future clinical guidelines on dietary-supplement use in patients on antithrombotic therapies, and to integrate new knowledge into various media outlets, including internet resources and web-based home-monitoring systems for antithrombotic therapies. The conference addressed existing gaps in the current knowledge about dietary supplements, their use, and their potential interactions with prescription drugs, as well as the need to formulate a forward-looking research agenda to address such gaps.

The meeting comprised seven sessions, which encompassed: 1) dietary supplements known to affect hemostasis and thrombosis; 2) what those effects on hemostasis are; 3) clinical data on dietary supplements affecting hemostasis and antithrombotic therapies; 4) new tools and methodologies for research and clinical practice in this area; 5) opinions and research priorities from a panel of experts; 6) public-health concerns from academia, industry, and regulatory bodies; and 7) dialogue with patient-care organizations.

The conference revealed six areas for action to develop an improved understanding of how dietary supplements may be used safely and effectively in conjunction with antithrombotic therapies.

  1. An Inventory of Dietary Supplements for Distribution to Emergency Rooms and Poison-Control Centers
    Currently, there is no comprehensive listing of manufacturers, product names, and product ingredients for the 30,000-plus dietary supplements on the market. Such a database would address a major public health need and would greatly assist the poison-control centers and emergency rooms, which respond to most of the cases of dietary supplement–drug interactions. The conference organizers and participants felt that this action should be a high priority to help manage interactions and risk in acute, emergency cases. Such information would also be useful for future compiling and analyzing case reports covering supplement interactions with antithrombotic drugs.

  2. A Research Agenda Aimed at Short- and Long-Term Patient Care and Safety
    The conference organizers and participants recognized the need for real-world data on dietary-supplement use and interactions with anticoagulant and antiplatelet therapies in special populations, such as the elderly, women (especially during pregnancy and lactation), minorities, patients with comorbid conditions (hepatic or renal impairment), and children. It was recommended that cases from poison centers and emergency rooms throughout the country should be entered in a national registry, and that research utilizing case-control studies in anticoagulation clinics, as well as outcome studies on those patients taking and those patients not taking concomitant herbal medicines or ingredients, should be conducted. These types of data would substantially raise the level of public health awareness and enhance patient care and safety in the United States. Potential sources of funding were discussed.

  3. Improved Case Reporting and History Taking on Patients with Likely Drug–Dietary Supplement Interactions
    Improvements in case reporting on patients with likely drug-dietary supplement interactions should ultimately result in improved background data for research in and monitoring of interactions between dietary supplements and antithrombotic therapies. This recommendation also includes the development of an accessible, internet repository for researchers and healthcare providers who need to report incidents and refer to relevant case reports. For this purpose, a properly implemented Web site, hosted either by the Food and Drug Administration (FDA) or the NIH, as well as simplified case reporting form and process, could be utilized. The web-based reporting system would be designed to prompt reporters to enter all pertinent information, and would filter or prioritize the case reports based on the amount of relevant information provided. Expert systems could also be used to assess data trends which demand immediate attention. The Web site would also give users a printout or an electronic version of the report (for publishing purposes) and, perhaps most importantly, it would automatically upload the report to the FDA or NIH database. These actions should allow more timely, accurate, and scientifically based conclusions to be drawn about interactions between dietary supplements and prescribed therapies.

  4. Improved Communication
    Understanding which dietary supplements are being used by patients and their effects has lagged because inadequate information has flowed to researchers and healthcare providers. Efforts need to be made to improve the way medical professionals and the healthcare community collect information on supplement use. The conference organizers recommend the involvement of NIH in these efforts. Organizers hope to begin this process with new educational programs at some of the larger society meetings, such as those for the American Society of Hematology (ASH) and the American Heart Association (AHA). The organizers will also seek to collaborate with the American College of Chest Physicians (ACCP) in rewriting the next version of its consensus guidelines for antithrombotic therapy to include a section on the use of dietary supplements. With regard to public outreach, the National Consumers League, which was represented at the conference, is seen as an excellent potential collaborator and as an excellent source of consumer information. Lastly, the NIH Web sites should consider having an area dedicated to dietary supplements, their use, and interactions with antiplatelet and anticoagulant therapies.

  5. Regulatory Improvements: Incident Reporting, Quality Data Collection, and Warning Labels
    Increased information on product names, better data on the contents of dietary supplements, and a change in the warning labels indicating known and potential interactions are needed. In light of the difficulty in changing the labeling on dietary supplements, the conference organizers recommend that the FDA consider requiring better labeling on prescription drugs with respect to potential interactions with dietary supplements. For example, current warnings on important drugs, such as warfarin, are inadequate, and more detailed warnings on prescription-drug labels would be a first step at better informing the public of known and uncertain hazards. Labeling changes would be based on what is already known and updated as more scientific data accumulates.

  6. Wider Collaboration and Information Sharing
    Progress can be achieved by formalizing input from and collaborating with experts who exist nationally, in Europe, and elsewhere —an activity the conference organizers recommend strongly as follow-up to these sessions. Moreover, educational seminars at scientific and medical conferences, such as those held by ASH and AHA, are recommended as annual training opportunities for fellows, physicians, and other healthcare providers. The organizers hope that the sponsors of this conference would also become involved in such efforts.
NHLBI - National Heart, Lung, and Blood Institute

ODS - Office of Dietary Supplements

CC - NIH Clinical Center

NCCAM - National Center for Complementary and Alternative Medicine

NINDS - National Institute of Neurological Disorders and Stroke

ORD - Office of Rare Diseases

Foundation for the National Institutes of Health

National Institutes of Health Department of Health and Human Services FirstGov, Your First Click to the US Government