Interactions between Natural Health Products and Oral Anticoagulants: Spontaneous Reports in the Italian Surveillance System of Natural Health Products

Assessing the knowledge of medical undergraduates on oral anticoagulation therapy

Objective

Oral anticoagulant drugs, such as warfarin, are widely used for preventing and treating vascular and thromboembolic disease in patients with chronic atrial fibrillation, venous thrombosis, and coronary heart disease. As oral anticoagulant therapy has such a narrow therapeutic range, complications in administering these drugs can prove to have a detrimental effect on patients such as life-threatening bleeding might occur. It is therefore necessary to have an adequate knowledge about its actions and its interactions with other dietary factors or any other medication involved. This study was therefore formulated in order to evaluate the knowledge as well as to impart proper awareness to the medical undergraduate students about oral anticoagulation therapy such as to prevent any untoward situation that may arise from the process.

Methods

A cross-sectional descriptive study was used to assess the knowledge on oral anticoagulant therapy among the medical undergraduates of a tertiary care hospital. A pre-validated structured questionnaire consisting of 28 questions was adopted, and a separate questionnaire was used for each student. Timing of answering the questionnaire was set at 30 minutes. Scores were evaluated such as a correct answer was given a score of one and wrong answer awarded as zero. Adequate knowledge sore was set above 70% and inadequate knowledge at less than 40%.

Results

The response rate was found out to be 67.33% with gender distribution observed to be 71% females and 29% males. From the answers evaluated, overall average score of 67.3 ± 15.9 was obtained indicating that most of the respondents have adequate knowledge about the different mechanism, drug-drug interactions, drug-food interactions, and side effects of anticoagulant therapy, and 100% of the students are well aware about the complications and procedures involved to dissipate information about warfarin therapy.

Conclusions

Adequate exposure of students to clinical cases will further help them to focus on the importance of anticoagulation and strengthening their knowledge regarding anticoagulant drug therapy. This will influence the process of physician-patient communication for improving anticoagulation outcome.

Evidence-Based Anti-Diabetic Properties of Plant from the Occitan Valleys of the Piedmont Alps

Data on urban and rural diabetes prevalence ratios show a significantly lower presence of diabetes in rural areas. Several bioactive compounds of plant origin are known to exert anti-diabetic properties. Interestingly, most of them naturally occur in different plants present in mountainous areas and are linked to traditions of herbal use. This review will aim to evaluate the last 10 years of evidence-based data on the potential anti-diabetic properties of 9 plants used in the Piedmont Alps (North-Western Italy) and identified through an ethnobotanical approach, based on the Occitan language minority of the Cuneo province (Sambucus nigra L., Achillea millefolium L., Cornus mas L., Vaccinium myrtillus L., Fragaria vesca L., Rosa canina L., Rubus idaeus L., Rubus fruticosus/ulmifolius L., Urtica dioica L.), where there is a long history of herbal remedies. The mechanism underlying the anti-hyperglycemic effects and the clinical evidence available are discussed. Overall, this review points to the possible use of these plants as preventive or add-on therapy in treating diabetes. However, studies of a single variety grown in the geographical area, with strict standardization and titration of all the active ingredients, are warranted before applying the WHO strategy 2014-2023.

Complementary medicines used in ulcerative colitis and unintended interactions with cytochrome P450-dependent drug-metabolizing enzymes

Ulcerative colitis (UC) is an idiopathic, chronic inflammatory disease with multiple genetic and a variety of environmental risk factors. Although current drugs significantly aid in controlling the disease, many people have led to the application of complementary therapies due to the common belief that they are natural and safe, as well as due to the consideration of the side effect of current drugs. Curcumin, cannabinoids, wheatgrass, Boswellia, wormwood and Aloe vera are among the most commonly used complementary medicines in UC. However, these treatments may have adverse and toxic effects due to unintended interactions with drugs or drug-metabolizing enzymes such as cytochrome P450s; thus, being ignorant of these interactions might cause deleterious effects with severe consequences. In addition, the lack of complete and controlled long-term studies with the use of these complementary medicines regarding drug metabolism pose additional risk and unsafety. Thus, this review aims to give an overview of the potential interactions of drug-metabolizing enzymes with the complementary botanical medicines used in UC, drawing attention to possible adverse effects.

Herb-Drug Interaction in Inflammatory Diseases: Review of Phytomedicine and Herbal Supplements

Many people worldwide use plant preparations for medicinal purposes. Even in industrialized regions, such as Europe, where conventional therapies are accessible for the majority of patients, there is a growing interest in and usage of phytomedicine. Plant preparations are not only used as alternative treatment, but also combined with conventional drugs. These combinations deserve careful contemplation, as the complex mixtures of bioactive substances in plants show a potential for interactions. Induction of CYP enzymes and pGP by St John's wort may be the most famous example, but there is much more to consider. In this review, we shed light on what is known about the interactions between botanicals and drugs, in order to make practitioners aware of potential drug-related problems. The main focus of the article is the treatment of inflammatory diseases, accompanied by plant preparations used in Europe. Several of the drugs we discuss here, as basal medication in chronic inflammatory diseases (e.g., methotrexate, janus kinase inhibitors), are also used as oral tumor therapeutics.

The need for European harmonization of Nutrivigilance in a public health perspective: a comprehensive review

According to the European Union regulation, some countries have established a pre-market notification system for food supplements while others have not. As this regulation is unfulfilled, a notified and marketed food supplement ingredient in one country may be forbidden in another. Even though food supplements shall not be placed on the market if unsafe, some products may still expose the consumers to risks. The risk is increased by easier access due to worldwide dissemination fostered by the internet and free movement of goods in the European Union. The Rapid Alert System for Food and Feed and the Emerging Risks Exchange Network are described. To date, the European Union legislation does not include a provision to establish a dedicated vigilance system for food supplements (Nutrivigilance). Six European Union countries have nevertheless set up national systems, which are presented. The present lack of European Union data collection harmonization, does not allow easy cooperation between countries. This article advocates for creating a coordinated European Nutrivigilance System to detect and scrutinize adverse effects of food supplements. This, to help in directing science-based risk assessments and reinforce the science-based decision of policy makers to improve public health safety.

Medicinal plants with antithrombotic property in Persian medicine: a mechanistic review

Thrombosis is one of the major causes of morbidity and mortality in a wide range of vessels diseases. Due to the high prevalence of thromboembolic disorders investigations are being carried out on new antithrombotic agents with limited adverse side effects in which herbal medicines are considered as alternative remedies. Persian medicine (PM) as a traditional medicine has a good potential for pharmacotherapy based on its own principles and development of drugs via investigating PM literature. In PM manuscripts there are some concepts that express the management of blood clots and antithrombotic properties. This study reviewed the pharmacological effects of medicinal plants mentioned in PM literature for blood clot management in light of current knowledge. Plants mentioned in PM for management of blood clot belong to 12 families in which Apiaceae, Lamiaceae and Compositae were the most repeated ones. Among the proposed plants Allium sativum, Rosmarinus officinalis, Boswellia serrata, Sesamum indicum, Matricaria chamomilla and Carthamus tinctorius have been the most researched plants in modern antithrombotic studies while for some plants such as Helichrysum stoechas, Dracocephalum kotschi, Carum carvi, Bunium persicum and Lagoecia cuminoides no evidence could be found. One of the interesting notes in clot management in PM texts was introducing the target organ for some of the recommended herbs like Carum carvi and Bunium persicum for dissolving blood clot in stomach and Commiphora mukul for thrombosed hemorrhoid. It seems review of PM recommendations can help to design future researches for antithrombotic drugs discovering with more effectiveness and safety.

Old and new oral anticoagulants: Food, herbal medicines and drug interactions

The most commonly prescribed oral anticoagulants worldwide are the vitamin K antagonists (VKAs) such as warfarin. Factors affecting the pharmacokinetics of VKAs are important because deviations from their narrow therapeutic window can result in bleedings due to over-anticoagulation or thrombosis because of under-anticoagulation. In addition to pharmacodynamic interactions (e.g., augmented bleeding risk for concomitant use of NSAIDs), interactions with drugs, foods, herbs, and over-the-counter medications may affect the risk/benefit ratio of VKAs. Direct oral anticoagulants (DOACs) including Factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and thrombin inhibitor (dabigatran) are poised to replace warfarin. Phase-3 studies and real-world evaluations have established that the safety profile of DOACs is superior to those of VKAs. However, some pharmacokinetic and pharmacodynamic interactions are expected. Herein we present a critical review of VKAs and DOACs with focus on their potential for interactions with drugs, foods, herbs and over-the-counter medications.

Review on mechanisms and interactions in concomitant use of herbs and warfarin therapy

The effectiveness of warfarin, an oral anticoagulant originally derived from a plant, is strongly affected by patient's characteristics such as the age, presence of comorbidities, and concomitant use of another drug. Warfarin has the potential to interact with many drugs, medicinal plants, and food, which increases the risk of adverse events. A critical analysis of scientific literature was conducted to assess the interferences of medicinal plants with blood haemostasis and then with warfarin anticoagulation. We found 58 different plants that may alter the blood haemostasis and anticoagulation with warfarin. The herbs that showed the greatest potential to interact with warfarin include garlic, ginger, ginkgo, St. John's wort, and ginseng, i.e. plants normally consumed as food and also used for therapeutic purposes. The interactions between drugs and herbs are varied because of the complex chemical matrix of plants. Mainly coumarins, quinones, xanthones, terpenes, lignans, and vitamin K showed significant influence on warfarin treatment. In general, these plants can potentiate the effect of warfarin by stimulating anticoagulation in multiple ways, and the clinical outcome associated with this interaction is the increase of bleeding risk. Moreover, potential interactions between herbal products and drugs are a safety concern, especially for drugs with a narrow therapeutic index or for patients receiving drug treatment for chronic diseases, and both of these apply to warfarin pharmacotherapy. Therefore, this review article summarises the data on the influence of medicinal plants on warfarin treatment and analyses this information in view of the interaction targets. The relevant plants were categorised according to their target, and their effects are discussed in order to organise the isolated information and to highlight the need of further discussion and new studies on the safety of herbal medicines and warfarin.

Investigation of adverse effects of interactions between herbal drugs and natural blood clotting mechanism

Throughout the world, herbal medicines are consumed by most of the patients without considering their adverse effects. Many herbal medicines/plant extracts have been reported to interact with the natural blood clotting system. In continuation to this effort, thirty medicinal plant extracts were allowed to interact with citrated human blood and the clotting time was measured after re-calcification in vitro using Lee and White method. The aq. leaf ext. of Syzygium cumini and Camellia sinensis significantly prolonged the clotting time. In response to the prothrombin time and activated partial thromboplastin time tests, the ext. of C. sinensis showed normal APTT and marginally prolonged the PT to 16.7 s (control-15.2 s) while S. cumini showed normal PT but significantly prolonged the APTT to 66.9 s (control-20.7 s). This suggests that, C. sinensis acts on the extrinsic pathway while S. cumini on the intrinsic pathway. There are some common herbal formulations that are frequently used by the patients which contain above plant materials, like, Syzygium cumin in anti-diabetic formulations, while the ext. of C. sinensis is consumed frequently as beverage in many part of the world. Hence, patients having known bleeding tendency or haemophilia disease should take into account the interaction potential of these plants with the natural blood clotting system while taking herbal formulations containing above plants; specially, the patients suffering from intrinsic pathway factor deficiency should keep a limit on the consumption of S. cumini while extrinsic pathway factor deficiency patients should limit C. sinensis. Also, the medical practitioners should consider the patient's food consumption history before doing any major surgical procedures.

Warfarin Interactions with Medicinal Herbs

Recognition of the adverse effects of medicinal herbs is not routine and the reports on such effects are even less frequent in clinical practice. Potential herb-drug interactions are of a major safety concern, especially for drugs with narrow therapeutic indices like warfarin, which can lead to severe adverse reactions that are sometimes life-threatening. The interactions between warfarin and medicinal herbs described in the literature have been summarized in this paper relying on Medline database (via PubMed) using the key words: warfarin, herbal supplements and interactions. The references on the analyzed literature have been investigated in order to collect the existing data. The case reports with severe adverse effects such as spontaneous postoperative bleeding, formation of hematomas, hematemesis, melena, thrombosis, subarachnoid hemorrhage and/or subdural hematomas after concomitant use of warfarin and the medicinal herbs: Panax ginseng, Hypericum perforatum, Salvia milthiorizza, Gingko biloba, Serenoa repens, Angelica sinensis, Vaccinium species, Allium sativum, Zingiber officinale, Tanacetum parthenium, Lucium barbarum, Matricaria chamomilla, Boswellia serrata and Camellia sinensis have been estimated. Some of the interactions between warfarin and medicinal herbs have been well assessed proving that they are closely-dependent.

The interactions between warfarin and medicinal herbs, not generally reported in previous reviews, are presented in our review. The health professionals who are involved in treating the patients are expected to be fully informed about the interactions between warfarin and medicinal herbs in order to minimize the health risks of the patients.

Valerian: no evidence for clinically relevant interactions

In recent popular publications as well as in widely used information websites directed to cancer patients, valerian is claimed to have a potential of adverse interactions with anticancer drugs. This questions its use as a safe replacement for, for example, benzodiazepines. A review on the interaction potential of preparations from valerian root (Valeriana officinalis L. root) was therefore conducted. A data base search and search in a clinical drug interaction data base were conducted. Thereafter, a systematic assessment of publications was performed. Seven in vitro studies on six CYP 450 isoenzymes, on p-glycoprotein, and on two UGT isoenzymes were identified. However, the methodological assessment of these studies did not support their suitability for the prediction of clinically relevant interactions. In addition, clinical studies on various valerian preparations did not reveal any relevant interaction potential concerning CYP 1A2, 2D6, 2E1, and 3A4. Available animal and human pharmacodynamic studies did not verify any interaction potential. The interaction potential of valerian preparations therefore seems to be low and thereby without clinical relevance. We conclude that there is no specific evidence questioning their safety, also in cancer patients.

CYP2C9, VKORC1, CYP4F2, ABCB1 and F5 variants: influence on quality of long-term anticoagulation

AIMS

The study aims to evaluate the impact of genetic, demographic and clinical data on various measures of outcome of anticoagulation quality in patients.

PATIENTS AND METHODS

The study consisted of 310 patients receiving long-term oral anticoagulation therapy in our hospital. Apart from demographic and clinical variables, 21 SNPs (in 7 genes) were analyzed and compared with the outcomes of anticoagulation therapy. Various outcomes that were measured are; supra therapeutic INRs (INR >3, >6), anticoagulation stabilization, time taken to stabilize and proportion of INRs within (2-3), above (>3) and below (<2) therapeutic range.

RESULTS

Supra therapeutic INRs were influenced by CYP2C9*2, *3, CYP4F2 rs2108622, VKORC1-1639G>A, 1173C>T, rs55894764 along with concomitant drugs, smoking, body weight and height. Persistently fluctuating INRs/absolute instability correlated with VKORC1-1639G>A, gender, height and body mass index. The time taken to stabilize was associated with CYP4F2 rs2108622, CYP2C9*14, smoking, clinical indication and concomitant drugs. The overall distribution of INR was influenced by variants in CYP4F2 rs2108622, CYP2C9*3, rs9332230, VKORC1 1173C>T, -1639G>A, rs55894764, ABCB1 rs2032582, rs1128503, rs1045642 and F5 rs6025, age, smoking and concomitant drugs.

CONCLUSIONS

Knowledge of factors influencing the quality of long term anticoagulation can help clinicians to customize therapy either by dose variation, therapy with alternate choice of drug, concurrent heparin therapy and/or frequent INR monitoring.

Surveillance of suspected adverse reactions to herbal products used as laxatives

AIM

To describe and evaluate spontaneous reports of suspected adverse reactions (ARs) associated with herbal laxatives received by the Italian Medicines Agency and the Italian National Institute of Health between April 2002 and January 2011.

METHODS

Spontaneous reports of suspected ARs were individually analyzed by a multidisciplinary group of experts, and a causality assessment was performed.

RESULTS

Twenty-six reactions were reported during the study period. Of these, eight were associated with herbal medicinal products and 18 were related to herbal food supplements. Almost 80% of the reports on ARs involved women. The ARs, classified by System Organ Class, were associated with gastrointestinal, skin and subcutaneous tissue, and hepatobiliary disorders. Fifty percent of the reactions were serious, with the patients requiring hospitalization; of these, one was life-threatening. Most of the herbal remedies associated with the reported ARs contained liquorice, dandelion, and/or plants containing anthraquinones. Possible causes of the ARs were long-term use, idiosyncratic reactions or hypersensitivity, and interaction with other treatments. All of these factors and the presence of a large number of components in the same product increased the unpredictability of the final effect.

CONCLUSIONS

The total number of 26 ARs recorded in 8 years is limited; however, the an under-reporting effect cannot be excluded. Moreover, taking into account the seriousness of the reported ARs, the low number of reports does not represent a guarantee of safety. To reduce the risk of an adverse outcome, herbal laxatives should be used only over the short term.

Complementary and Alternative Drugs Use among Preoperative Patients: A Cross-Sectional Study in Italy

Complementary and alternative drugs (CADs) are widely used in preoperative patients and may lead to potential interactions and adverse reactions. The aim of our study is to evaluate the prevalence and the predictors of CADs use among preoperative patients using data from an Italian survey. This cross-sectional study, which enrolled 478 patients (response rate: 83.5%), was carried out in three Tuscany hospitals (Italy). The prevalence of CADs use was 49.8%: 233 out of 238 participants used herbal products and/or dietary supplements. Valeriana officinalis was the most reported product (19.4%). According to univariate analysis, users were commonly identified among middle-aged or older patients; unadjusted ORs were 2.1 (95% CI: 1.3–3.3) for patients aged 48–69 years, and 3.0 (95% CI: 1.9–4.7) for those of 70–95 years, when compared with individuals aged 18–47 years. Except for education and gender, adjusted estimates showed consistent results with univariate analyses: direct association was observed with higher education, and—although not significantly—with female gender. The high prevalence of CAD use in preoperative period could be suggestive of a certain risk of adverse effects due to CADs interactions. A careful medical history of CADs consumption should be ascertained before surgery.