Clinical Approach to Adverse Events and Interactions Related to Herbal and Dietary Supplements

Evaluation of resources for analyzing drug interactions

OBJECTIVE

The research sought to evaluate seven drug information resources, specifically designed for analyzing drug interactions for scope, completeness, and ease of use, and determine the consistency of content among the seven resources.

METHODS

A cross-sectional study was conducted where 100 drug-drug and drug-dietary supplement interactions were analyzed using 7 drug information resources: Lexicomp Interactions module, Micromedex Drug Interactions, Clinical Pharmacology Drug Interaction Report, Facts & Comparisons eAnswers, Stockley's Drug Interactions (10th edition), Drug Interactions Analysis and Management (2014), and Drug Interaction Facts (2015). The interaction sample was developed based on published resources and peer input. Two independent reviewers gathered data for each interaction from each of the 7 resources using a common form.

RESULTS

Eighty-two drug-drug and 18 drug-dietary supplement interactions were analyzed. Scope scores were higher for Lexicomp Interactions (97.0%), Clinical Pharmacology Drug Interaction Report (97.0%), and Micromedex Drug Interactions (93.0%) compared to all other resources (p<0.05 for each comparison). Overall completeness scores were higher for Micromedex Drug Interactions (median 5, interquartile range [IQR] 4 to 5) compared to all other resources (p<0.01 for each comparison) and were higher for Lexicomp Interactions (median 4, IQR 4 to 5), Facts & Comparisons eAnswers (median 4, IQR 4 to 5), and Drug Interaction Facts (4, IQR 4 to 5) compared to all other resources, except Micromedex (p<0.05 for each comparison). Ease of use, in terms of time to locate information and time to gather information, was similar among resources. Consistency score was higher for Micromedex (69.9%) compared to all other resources (p<0.05 for each comparison).

CONCLUSIONS

Clinical Pharmacology Drug Interaction Report, Lexicomp Interactions, and Micromedex Drug Interactions scored highest in scope. Micromedex Drug Interactions and Lexicomp Interactions scored highest in completeness. Consistency scores were overall low, but Micromedex Drug Interactions was the highest.

Dietary implications for patients receiving long-term oral anticoagulation therapy for treatment and prevention of thromboembolic disease

INTRODUCTION

The effectiveness of oral anticoagulation therapy with warfarin (a vitamin K antagonist) in the treatment of thromboembolic disease, including stroke prophylaxis in patients with atrial fibrillation is well recognised. However, warfarin has a narrow therapeutic window and an unpredictable anticoagulation response, which make it difficult to achieve and maintain optimal anticoagulation. Various dietary factors, including sudden changes in eating patterns, can significantly alter anticoagulation control, thereby potentially exposing patients to the risk of bleeding or thromboembolic complications. Dietary vitamin K intake is a particularly important factor, given the mechanism of action of warfarin. Areas covered: In this article, we cover the sources of vitamin K and their potential effect of dietary vitamin K on anticoagulation response to warfarin. We also discuss the results of studies on the effect of vitamin K supplementation on anticoagulation stability. Expert commentary: A stable dietary vitamin K, promoted by daily oral vitamin K supplementation, can improve anticoagulation stability in patients on warfarin therapy. There is experimental evidence in animals that dietary vitamin K affects anticoagulation response to the direct thrombin inhibitor, ximelagatran. Whether dietary vitamin K affects anticoagulation response to the currently licensed direct oral anticoagulants (DOACs) in man remains to be investigated.

A review of potential harmful interactions between anticoagulant/antiplatelet agents and Chinese herbal medicines

Background

The risks attributed to drug-herb interactions, even when known, are often ignored or underestimated, especially for those involving anti-clotting drugs and Chinese medicines. The aim of this study was to structurally search and evaluate the existing evidence-based data associated with potential drug interactions between anticoagulant/antiplatelet drugs and Chinese herbal medicines (CHMs) and evaluate the documented mechanisms, consequences, and/or severity of interactions.

Methodology and Findings

Information related to anticoagulant/antiplatelet drug-CHM interactions was retrieved from eight interaction-based textbooks, four web resources and available primary biomedical literature. The primary literature searches were conducted in English and/or Chinese from January 2000 through December 2011 using the secondary databases (e.g., PubMed, Airiti Library, China Journal full-text database). The search terms included the corresponding medical subject headings and key words. Herbs or natural products not used as a single entity CHM or in Chinese Medicinal Prescriptions were excluded from further review. The corresponding mechanisms and severity ratings of interactions were retrieved using MicroMedex®, Lexicomp® and Natural Medicines Comprehensive Database®. Finally, we found 90 single entity CHMs contributed to 306 documented drug-CHM interactions. A total of 194 (63.4%) interactions were verified for its evidence describing possible mechanisms and severity. Of them, 155 interactions (79.9%) were attributable to pharmacodynamic interactions, and almost all were rated as moderate to severe interactions. The major consequences of these interactions were increased bleeding risks due to the additive anticoagulant or antiplatelet effects of the CHMs, specifically danshen, dong quai, ginger, ginkgo, licorice, and turmeric.

Conclusions/Significance

Conventional anticoagulants and antiplatelet drugs were documented to have harmful interactions with some commonly used single entity CHMs. For those patients who are taking conventional anti-clotting medications with CHMs for cardiovascular or cerebrovascular diseases, the potential risks of increased bleeding due to drug-CHM interactions should not be ignored.

Evaluation of documented drug interactions and contraindications associated with herbs and dietary supplements: a systematic literature review

BACKGROUND AND AIMS

The use of herbs and dietary supplements (HDS) alone or concomitantly with medications can potentially increase the risk of adverse events experienced by the patients. This review aims to evaluate the documented HDS-drug interactions and contraindications.

METHODS

A structured literature review was conducted on PubMed, EMBASE, Cochrane Library, tertiary literature and Internet.

RESULTS

While 85 primary literatures, six books and two web sites were reviewed for a total of 1,491 unique pairs of HDS-drug interactions, 213 HDS entities and 509 medications were involved. HDS products containing St. John's Wort, magnesium, calcium, iron, ginkgo had the greatest number of documented interactions with medications. Warfarin, insulin, aspirin, digoxin, and ticlopidine had the greatest number of reported interactions with HDS. Medications affecting the central nervous system or cardiovascular system had more documented interactions with HDS. Of the 882 HDS-drug interactions being described its mechanism and severity, 42.3% were due to altered pharmacokinetics and 240 were described as major interactions. Of the 152 identified HDS contraindications, the most frequent involved gastrointestinal (16.4%), neurological (14.5%), and renal/genitourinary diseases (12.5%). Flaxseed, echinacea, and yohimbe had the largest number of documented contraindications.

CONCLUSIONS

Although HDS-drug interactions and contraindications primarily concerned a relatively small subset of commonly used medications and HDS entities, this review provides the summary to identify patients, HDS products, and medications that are more susceptible to HDS-drug interactions and contraindications. The findings would facilitate the health-care professionals to communicate these documented interactions and contraindications to their patients and/or caregivers thereby preventing serious adverse events and improving desired therapeutic outcomes.

Nutritional supplements in the surgical patient

This article presents an overview of the current knowledge, status, and use of supplements by patients before surgical operations, together with the benefits expected of the supplements by the patients. The indications, potential advantages and disadvantages, and the relationships with various aspects of the preoperative preparation and postoperative management of surgical patients are discussed, with emphasis on the significant percentage of this population that is deficient in fundamental nutrients. Recent revisions and recommendations for some of the macronutrients are presented, together with a summary of federal regulations and an oversight of supplements.

Dietary supplements and herbal medicine toxicities-when to anticipate them and how to manage them

BACKGROUND

Dietary supplements and herbal medicines are gaining popularity in many developed countries.

AIMS

Although most can be used without any problem, serious toxicities do occur.

METHODS

Problems can be anticipated when they are used for non-traditional indications, at excessive dose, for prolonged duration, or by patients who are also on multiple modern pharmaceuticals. Problems should also be anticipated when these products claim to be able to relieve symptoms rapidly or when herbs with pronounced pharmacological effects or toxic components are used.

RESULTS

Resuscitation, symptomatic and supportive care are the most important aspects of management of toxicities from these products.

CONCLUSION

This article reviews when problems with these products can be anticipated and outlines a practical approach to management.

Clinical and analytical toxicology of dietary supplements: a case study and a review of the literature

The use of dietary supplements has grown dramatically in the last decade. A large number of dietary and herbal supplements escape regulatory and quality control; components of these preparations are poisonous and may contain, among other toxins, heavy metals. Uncontrolled use of dietary and herbal supplements by special populations, such as the military, may therefore pose a health risk. Clinical symptoms are not always properly attributed to dietary supplements; patients often do not mention supplement use to their health care provider. Therefore, a health risk estimate is hard to make on either the individual or the population level. The literature on this issue was reviewed and discussed in the light of a representative clinical-chemical case study. This case study was performed on a host of preparations that were used by one single individual in the military. Both essential (chromium, copper, zinc, and iron) and poisonous (arsenic, lead, and nickel) trace elements were determined using inductively coupled plasma combined with optical emission spectrometry (ICP-OES) or with mass spectrometry (ICP-MS). Arsenic and lead were detected at exposure levels associated with health risks. These health risks were detected predominantly in hormone-containing supplements and the herbs and botanicals used for performance enhancement. To the extent that this is a representative sample, there is an underestimation of supplement use and supplement risk in the US military, if not in the general population. Since clinical symptoms may be attributed to other causes and, unless patients are specifically asked, health care providers may not be aware of their patients' use of dietary supplements, a strong support of laboratory diagnostics, such as a toxicological screening of blood or urine, is required. In addition, screening of the preparations themselves may be advised.