Prediction of herb-drug metabolic interactions: a simulation study

Modeling Pharmacokinetic Natural Product-Drug Interactions for Decision-Making: A NaPDI Center Recommended Approach

The popularity of botanical and other purported medicinal natural products (NPs) continues to grow, especially among patients with chronic illnesses and patients managed on complex prescription drug regimens. With few exceptions, the risk of a given NP to precipitate a clinically significant pharmacokinetic NP-drug interaction (NPDI) remains understudied or unknown. Application of static or dynamic mathematical models to predict and/or simulate NPDIs can provide critical information about the potential clinical significance of these complex interactions. However, methods used to conduct such predictions or simulations are highly variable. Additionally, published reports using mathematical models to interrogate NPDIs are not always sufficiently detailed to ensure reproducibility. Consequently, guidelines are needed to inform the conduct and reporting of these modeling efforts. This recommended approach from the Center of Excellence for Natural Product Drug Interaction Research describes a systematic method for using mathematical models to interpret the interaction risk of NPs as precipitants of potential clinically significant pharmacokinetic NPDIs. A framework for developing and applying pharmacokinetic NPDI models is presented with the aim of promoting accuracy, reproducibility, and generalizability in the literature. SIGNIFICANCE STATEMENT: Many natural products (NPs) contain phytoconstituents that can increase or decrease systemic or tissue exposure to, and potentially the efficacy of, a pharmaceutical drug; however, no regulatory agency guidelines exist to assist in predicting the risk of these complex interactions. This recommended approach from a multi-institutional consortium designated by National Institutes of Health as the Center of Excellence for Natural Product Drug Interaction Research provides a framework for modeling pharmacokinetic NP-drug interactions.

Multifaceted Factors Causing Conflicting Outcomes in Herb-Drug Interactions

Metabolic enzyme and/or transporter-mediated pharmacokinetic (PK) changes in a drug caused by concomitant herbal products have been a primary issue of herb and drug interactions (HDIs), because PK changes of a drug may result in the alternation of efficacy and toxicity. Studies on HDIs have been carried out by predictive in vitro and in vivo preclinical studies, and clinical trials. Nevertheless, the discrepancies between predictive data and the clinical significance on HDIs still exist, and different reports of HDIs add to rather than clarify the confusion regarding the use of herbal products and drug combinations. Here, we briefly review the underlying mechanisms causing PK-based HDIs, and more importantly summarize challenging issues, such as dose and treatment period effects, to be considered in study designs and interpretations of HDI evaluations.

Understanding the relevance of herb-drug interaction studies with special focus on interplays: a prerequisite for integrative medicine

Integrative medicine refers to the blending of conventional and evidence-based complementary medicines and therapies with the aim of using the most appropriate of either or both modalities for ultimate patient benefits. One of the major hurdles for the same is the chances of potential herb–drug interactions (HDIs). These HDIs could be beneficial or harmful, or even fatal; therefore, a thorough understanding of the eventualities of HDIs is essential so that a successful integration of the modern and complementary alternative systems of medicine could be achieved. Here, we summarize all the important points related to HDIs, including types, tools/methods for study, and prediction of the HDIs, along with a special focus on interplays between drug metabolizing enzymes and transporters. In addition, this article covers future perspective, with a focus on background endogenous players of interplays and approaches to predict the drug–disease–herb interactions so as to fetch the desired effects of these interactions.

Concurrent Use of Conventional Drugs with Chinese Herbal Products in Taiwan: A Population-based Study

The increased use of Chinese herbal products (CHPs) worldwide has raised the concern of herb-drug interactions. The aim of this study was to determine the prevalence and utilization patterns of concurrent use of conventional drugs and CHPs in Taiwan. The usage and frequency of services in the co-prescription of a CHP and a conventional drug were evaluated. Subjects were recruited from a simple random sample of 1,000,000 subjects from over 22 million beneficiaries of the National Health Insurance in 2007. The logistic regression method was employed to estimate the odds ratios (ORs) for the co-prescription of a CHP and a conventional drug (CH + D) and a conventional drug alone (D-alone). The prevalence of the CH + D was 14.1%. Females, regular salary earners, and elderly (65 years and above) were more likely to consume a CHP and a conventional drug concurrently. Painkillers, especially acetaminophen, and anti-cough medicines were the top two conventional drugs that were most frequently co-prescribed with a CHP. Anti-cough medication is the most common conventional drug co-prescribed with CHP, after painkillers. We recommend that safety issues be investigated in future research and integrating both healthcare technologies may be beneficial for the overall health and quality of life of patients.

Established HPLC fraction analysis to predict furanocoumarin-based herb-drug metabolic interactions

An attempt was made in this study to predict the potential for metabolic interactions of herbal extracts of drugs from their chromatographic profiles in reverse-phase high-performance liquid chromatography (RP-HPLC). Twenty-nine structurally related furanocoumarin compounds with known inhibitory interactions with cytochrome P450 3A (CYP3A), which is important for phase-I drug metabolism, were selected as a model system. A sigmoidal relationship was established between the CYP3A inhibitory potency (y) and the RP-HPLC total peak response unit (R(u), x) as y = 85.36 x (14.86 + x)⁻¹ with a correlation coefficient of 0.63. The sigmoidal curve could be divided into three ranges designated low, medium and high risk that were used to indicate the relative inhibitory potency of the metabolic interactions of herbs or traditional Chinese herb medicines with CYP3A. These predictive classifications provide information or might be useful for 'risk category' decisions concerning herb-drug interactions.

Concurrent use of corticosteroids with licorice-containing TCM preparations in Taiwan: a National Health Insurance Database study

OBJECTIVES

This study used a nationwide population-based dataset from the 1997-2003 National Health Insurance claims to explore the prevalence, frequency, and relative risk of concurrent use of systemic corticosteroids with licorice-containing Traditional Chinese Medicine (TCM) preparations that might possibly result in drug-herb interactions.

DESIGN

This study was based on the complete datasets of Western medicine and TCM outpatient reimbursement claims from 1997 to 2003 contained in the National Health Insurance Research Database of Taiwan. According to the date and duration of prescriptions, the patients who concurrently used systemic corticosteroids with licorice-containing TCM preparations were derived for statistical analysis.

SETTING

This study was set in Taiwan.

OUTCOME MEASURES

Descriptive statistics were used to analyze the demographics of patients who used corticosteroids with licorice-containing TCM preparations concurrently, including age, gender, and the frequency and percentage of major diseases in International Classification of Diseases, 9th version, Clinical Modification (ICD-9-CM) categories. The relative risk of potential corticosteroid-herb interaction was also analyzed with respect to different characteristics of the patients (age, sexuality etc.).

RESULTS

The prevalence of concurrent use of systemic corticosteroids with licorice-containing TCM preparations through prescriptions from different Chinese medicine and Western medicine physicians was 1.495%. Among the major disease categories, ICD-9-CM codes 280-289 had the highest prevalence rate of 3.803%.

CONCLUSIONS

Potential risk of corticosteroid-licorice interactions may happen, even through formal medical services. In the future, such educational propagations should be reinforced. Furthermore, an alert device that includes well-recognized drug-herb interactions should be built into every hospital's computer system to remind physicians to be cautious on drug safety.

Clinical risk management of herb-drug interactions

The concomitant use of conventional and herbal medicines can lead to clinically relevant herb-drug interactions. Clinical risk management offers a systematic approach to minimize the untoward consequences of these interactions by paying attention to: (i) risk identification and assessment; (ii) development and execution of risk reduction strategies; and (iii) evaluation of risk reduction strategies. This paper reviews which steps should be explored or taken in these domains to improve the clinical risk management of adverse herb-drug interactions.