54 DEVELOPMENT OF RECOMMENDATIONS BASED ON MECHANISMS AND EVIDENCE OF INTERACTION BETWEEN HERBAL SUPPLEMENTS AND CARDIOVASCULAR DRUGS

There are 23 million people in the United States diagnosed with heart disease and the majority of these patients rely on prescription medication as part of their treatment regimen. With the high rates of herbal supplement use, there are certain to be drug interactions that occur without physician awareness. Therefore, physicians need to be aware of potential drug interactions that may result from their concomitant use with prescription medications. By understanding and appreciating important mechanisms, physicians can better screen for and avoid adverse events. This report offers the results of a systematic review of the literature regarding interactions between cardiovascular (CV) drugs and top-selling herbal supplements: echinacea, garlic, ginkgo biloba, ginseng, kava, saw palmetto, St. John9s wort, and valerian root. The PubMed literature search included CV drug herbal interactions, CV drug metabolizing pathways, and incidences of adverse events that were attributed to drug-herbal interactions. All primary literature was cross-referenced with the Herbal PDR and the Comprehensive Medicines Natural Database. The strength of evidence for each herbal interaction was rated with commonly used scales based on study design, validity, population size, and bias. This three point scale was weighted against the severity of potential interactions for the herbal and CV drugs. The severity of the interaction was scored based on the consequence or outcome: 1-documented hospitalization, emergency care or intervention required due to interactions; 2-proposed serious potential for interaction involving hospitalization, emergency care or intervention; and 3-non-emergent intervention required to treat or reduce effects of interaction. Based on this procedure, recommendations were color coded. Red indicates a strong potential for interaction with dangerous consequences that should be avoided. Orange indicates a strong potential for interaction with dangerous consequences that should be avoided, which is based on theoretical evidence only. Yellow indicates less potential for interaction with a lesser degree of consequence should interactions occur. Physicians should note caution regarding these interactions. For the supplements studied, 1 scored red (kava), 3 scored orange (echinacea, ginkgo biloba, and St. John9s wort), 3 scored yellow (garlic, ginseng, and saw palmetto), and valerian root had no known CV drug interactions. These scores along with known interactions serve as a tool to guide physicians when screening for interactions between herbal supplements and CV medications.