Clinical risk management of herb-drug interactions

BABINE: An original and user-friendly scale for the simple and quick management of herb-drug interactions in clinical practice

BACKGROUND

While more and more people tend to use herbal products thinking they are safer than conventional western medicine, the reality is other. If natural products are bio-active and possess potential therapeutic activities, then the benefit/risk balance should be considered like any other health product. Some herbs are known to have the potential to interact with patient's treatment and to cause adverse drug reactions. While these are scarce, they are potentially harmful, and can lead to major sequels and even death in some cases. Despite these known facts, little guidelines about how to evaluate the risk of interaction and to handle them exist in literature. Notably, few scales allowing to assess the risk of a specific combination of herbs and drugs exist.

METHOD

We propose a new scoring method BABINE (Boosting Analysis of Bibliography for herb- drug INteraction Evaluation) and discuss a scale to evaluate this risk based on iterative rounds of experts' discussion.

RESULTS

After 6 rounds of case reports/clinical studies evaluation, we analyzed and synthesized criteria identified as important by the experts and developed a corresponding evaluation scale.

CONCLUSION

Even if our scale greatly simplifies pharmacological events, we believe it provides a robust and transparent way to rapidly assess the risk of adverse event.

Herb-antitumour drug interaction risks: retrospective integrative oncology study

OBJECTIVES

The use of herbal medicine is widespread among oncology patients, with potentially negative interactions with anticancer drugs. This study identified herbal products being used among a cohort of oncology patients, assessing the risk for an herb-drug interaction.

METHODS

Herbal medicine use was examined among 42 oncology patients, identifying potential herb-drug interactions using four online sites. The risk for an interaction was scored using the Working Group on Pharmacotherapy and Drug Information of the Royal Dutch Association for the Advancement of Pharmacy (KNMP).

RESULTS

Most patients (62%) reported herbal medicine use, with 70 products identified; 8 herbs and 13 herbal formulas with unidentified components; and 24 anticancer drugs. Herbal medicine use was more prevalent among female patients (p=0.038), with only nine potential herb-drug interactions identified on at least one site. A maximal KNMP Score of 1 (ie, incomplete published case report) was found with only one interaction.

CONCLUSIONS

The risk for interactions between herbal products and anticancer drugs is difficult to predict, with online search engines providing limited and inconsistent information. Clinical implications of herb-antitumor drug interactions need to be better understood, enabling patients and their oncology healthcare providers to make informed decisions regarding their care.

Safety Concerns Related to the Simultaneous Use of Prescription or Over-the-Counter Medications and Herbal Medicinal Products: Survey Results among Latvian Citizens

The use of herbal medicines is increasing worldwide. While the safety profile of many herbal medicines is promising, the data in the literature show important interactions with conventional drugs that can expose individual patients to high risk. The aim of this study was to investigate the experience of the use of herbal medicines and preparations and the risks of interactions between herbal and conventional medicines among Latvian citizens. Data were collected between 2019 and 2021 using a structured questionnaire designed for pharmacy customers in Latvia. Electronic databases such as Drugs.com, Medscape, and European Union herbal monographs were reviewed for the risk of drug interactions and potential side effects when herbal medicines were involved. The survey included 504 respondents. Of all the participants, 77.8% used herbal preparations. Most of the participants interviewed used herbal remedies based on the recommendation of the pharmacist or their own initiative. A total of 38.3% found the use of herbal remedies safe and harmless, while 57.3% of respondents regarded the combination of herbal and regular drugs as unsafe. The identified herbal medicines implicated in the potential risk of serious interactions were grapefruit, St. John's wort, and valerian. As the risks of herb-drug interactions were identified among the respondents, in the future, both pharmacy customers and healthcare specialists should pay more attention to possible herb-drug interactions of over-the-counter and prescription medications.

Expanding potential targets of herbal chemicals by node2vec based on herb-drug interactions

BACKGROUND

The identification of chemical-target interaction is key to pharmaceutical research and development, but the unclear materials basis and complex mechanisms of traditional medicine (TM) make it difficult, especially for low-content chemicals which are hard to test in experiments. In this research, we aim to apply the node2vec algorithm in the context of drug-herb interactions for expanding potential targets and taking advantage of molecular docking and experiments for verification.

METHODS

Regarding the widely reported risks between cardiovascular drugs and herbs, Salvia miltiorrhiza (Danshen, DS) and Ligusticum chuanxiong (Chuanxiong, CX), which are widely used in the treatment of cardiovascular disease (CVD), and approved drugs for CVD form the new dataset as an example. Three data groups DS-drug, CX-drug, and DS-CX-drug were applied to serve as the context of drug-herb interactions for link prediction. Three types of datasets were set under three groups, containing information from chemical-target connection (CTC), chemical-chemical connection (CCC) and protein-protein interaction (PPI) in increasing steps. Five algorithms, including node2vec, were applied as comparisons. Molecular docking and pharmacological experiments were used for verification.

RESULTS

Node2vec represented the best performance with average AUROC and AP values of 0.91 on the datasets "CTC, CCC, PPI". Targets of 32 herbal chemicals were identified within 43 predicted edges of herbal chemicals and drug targets. Among them, 11 potential chemical-drug target interactions showed better binding affinity by molecular docking. Further pharmacological experiments indicated caffeic acid increased the thermal stability of the protein GGT1 and ligustilide and low-content chemical neocryptotanshinone induced mRNA change of FGF2 and MTNR1A, respectively.

CONCLUSIONS

The analytical framework and methods established in the study provide an important reference for researchers in discovering herb-drug interactions, alerting clinical risks, and understanding complex mechanisms of TM.

Herb-anticancer drug interactions in real life based on VigiBase, the WHO global database

Cancer patients could combine herbal treatments with their chemotherapy. We consulted VigiBase, a WHO database of individual case safety reports (ICSRs) which archives reports of suspected Adverse Drug Reactions (ADRs) when herbal products are used in conjunction with anti-cancer treatment. We focused on the possible interactions between antineoplastic (L01 ATC class) or hormone antagonists (L02B ATC class) with 10 commonly used herbs (pineapple, green tea, cannabis, black cohosh, turmeric, echinacea, St John’s wort, milk thistle and ginger) to compare ADRs described in ICSRs with the literature. A total of 1057 ICSRs were extracted from the database but only 134 were complete enough (or did not concern too many therapeutic lines) to keep them for analysis. Finally, 51 rationalizable ICSRs could be explained, which led us to propose a pharmacokinetic or pharmacodynamic interaction mechanism. Reports concerned more frequently women and half of the rationalizable ICSRs involved Viscum album and Silybum marianum. 5% of the ADRs described could have been avoided if clinicians had had access to the published information. It is also important to note that in 8% of the cases, the ADRs observed were life threatening. Phytovigilance should thus be considered more by health care professionals to best treat cancer patients and for better integrative care.

An Overview of the Evidence and Mechanism of Drug-Herb Interactions Between Propolis and Pharmaceutical Drugs

With the growing interest in the medicinal use of propolis, numerous studies have reported significant interactions between propolis extract and pharmaceutical drugs which may result in great clinical benefits or risks. The present study aims to review the drug-herb interactions of the full-spectrum propolis extract and main pharmaceutical drugs from the pharmacodynamic and pharmacokinetic aspects and elucidate the underlying pharmacological mechanisms. A literature search was conducted between June 2021 and February 2022 in Google Scholar, PubMed, MEDLINE, and EMBASE databases to include English studies from years 2000 to 2022 that evaluated the interaction of full-spectrum propolis extract and standard pharmaceutical drugs/cytochromes P450s. Studies that looked into geopropolis, propolis fractions, and isolated compounds, or interaction of propolis with foods, bioactive molecules, or receptors other than standard pharmaceutical drugs were excluded. From a pharmacodynamic perspective, propolis extract exhibited positive or synergistic interaction with several chemotherapeutic drugs by enhancing antitumor activity, sensitizing the chemoresistance cell lines, and attenuating multi-organ toxicity. The molecular mechanisms were associated with upregulating the apoptotic signal and immunomodulatory activity and attenuating oxidative damage. Propolis extract also enhanced the anti-bacterial and antifungal activities of many antimicrobial drugs against sensitive and resistant organisms, with an effect against the gram-positive bacteria stronger than that of the gram-negative bacteria. The synergistic action was related to strengthened action on interfering cell wall integrity and protein synthesis. The strong antioxidant activity of propolis also strengthened the therapeutic effect of metformin in attenuating hyperglycemia and pancreatic damage, as well as mitigating oxidative stress in the liver, kidney, and testis. In addition, propolis showed a potential capacity to enhance short-term and long-term memory function together with donepezil and improve motor function with levodopa and parasite killing activity with praziquantel. Pharmacokinetic studies showed inhibitory activities of propolis extracts on several CYP450 enzymes in vitro and in vivo. However, the effects on those CYP450 were deemed insignificant in humans, which may be attributed to the low bioavailability of the contributing bioactive compounds when administered in the body. The enhanced bioactivities of propolis and main pharmaceutical drugs support using propolis in integrative medicine in anti-cancer, anti-microbial, antidiabetic, and neurological disorders, with a low risk of altered pharmacokinetic activities.

Negligible Effect of Quercetin in the Pharmacokinetics of Sulfasalazine in Rats and Beagles: Metabolic Inactivation of the Interaction Potential of Quercetin with BCRP

Breast cancer resistance protein (BCRP) mediates pharmacokinetic drug interactions. This study evaluated the potential of quercetin to inhibit and induce BCRP in vitro and in vivo. The inhibition of BCRP was investigated for quercetin and its metabolites using BCRP/mBcrp1-overexpressing MDCKII cells by flow cytometry. The induction of BCRP was investigated in LS174T cells using quantitative PCR. The expression of rat BCRP in rat small intestine, liver, and kidney was also measured after multiple administrations of quercetin in rats (50, 100, and 250 mg/kg, seven days). The in vivo pharmacokinetic changes of sulfasalazine following single or multiple administration of quercetin in rats and beagles were investigated. Although the induction effect of quercetin on BCRP was observed in vitro, the in vivo expression of rat BCRP was not changed by multiple quercetin administrations. Oral administration of quercetin did not affect the plasma concentration or pharmacokinetic parameters of sulfasalazine, regardless of dose and dosing period in either rats or beagles. In addition, the inhibitory effect of quercetin metabolites on BCRP/mBcrp1 was not observed. These results suggest that the in vivo drug interaction caused by quercetin via BCRP was negligible, and it may be related to the metabolic inactivation of quercetin for the inhibition of BCRP.

Potential propensity of traditional herbal materials ingested by collegiate athletes in South China for their consuming health care

In south China, traditional herbal medicines have been widely used as functional foods or dietary supplements for daily health care. Many plant-derived chemical substances with biological activity are inadvertently ingested by collegiate athletes daily through canton-style herbal tea or herbal slow-cooked soup. In the view of the complexity of herbal ingredients, it is still no full survey reported for the sports risk of plant-derived sports doping. This research is firstly a descriptive statistical analysis. Collegiate athletes with different socio-economic characteristics from medical colleges in 3 different regions in China participated in the questionnaire survey. Three survey forms, including the oral interview, email inquiry, handing out and recovering the questionnaires in live, were developed and performed by researchers. It was first found that collegiate athletes resorted to some traditional herbal materials to protect their health care that there were regional differences (P < .01). Collegiate athletes with Health Fitness and Traditional Wushu as their sports expertise showed a higher frequency of recognition or ingestion in the use of traditional herbal materials (P < .01), while their different living types and cuisine preferences did not seem to be associated with the ingestion frequency of traditional herbal materials. In addition, in the view of the significant differences in the use of herbal preparations to relieve sports stress among young athletes in different regions (P < .01), the findings strongly suggested that athletes should strictly control their use of various herbal preparations during sports training and competition, including herbal wines, herbal oils, topical plasters, analgesic tablets.

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.

Herb-drug interactions: a novel algorithm-assisted information system for pharmacokinetic drug interactions with herbal supplements in cancer treatment

PURPOSE

To develop a system to estimate the risk of herb-drug interactions that includes the available evidence from clinical and laboratory studies, transparently delineates the algorithm for the risk estimation, could be used in practice settings and allows for adaptation and update.

METHODS

We systematically searched Drugbank, Transformer, Drug Information Handbook, European and German Pharmacopoeia and MEDLINE for studies on herb-drug interactions of five common medicinal plants (coneflower, ginseng, milk thistle, mistletoe and St. John's wort). A diverse set of data were independently extracted by two researchers and subsequently analysed by a newly developed algorithm. Results are displayed in the form of interaction risk categories. The development of the algorithm was guided by an expert panel consensus process.

RESULTS

From 882 publications retrieved by the search, 154 studies were eligible and provided 529 data sets on herbal interactions. The developed algorithm prioritises results from clinical trials over case reports over in vitro investigations and considers type of study, consistency of study results and study outcome for clinical trials as well as identification, permeability, bioavailability, and interaction potency of an identified herbal perpetrator for in vitro investigations. Risk categories were assigned to and dynamically visualised in a colour-coded matrix format.

CONCLUSIONS

The novel algorithm allows to transparently generate and dynamically display herb-drug interaction risks based on the available evidence from clinical and laboratory pharmacologic studies. It provides health professionals with readily available and easy updatable information about the risk of pharmacokinetic interactions between herbs and oncologic drugs.

Evaluation of the impact of 16-dehydropregnenolone on the activity and expression of rat hepatic cytochrome P450 enzymes

16-dehydropregnenolone (DHP) is a promising novel antihyperlipidemic agent developed and patented by Central Drug Research Institute (CDRI), India. The purpose of the present study was to investigate whether DHP influences the activities and mRNA expression of hepatic drug-metabolizing cytochrome P450 (CYP) enzymes (CYP1A2, CYP2C11, CYP2D2, CYP2E1 and CYP3A1) in Sprague-Dawley (SD) rats. A cocktail suspension of CYP probe substrates which contained caffeine (CYP1A2), tolbutamide (CYP2C11), dextromethorphan (CYP2D2), chlorzoxazone (CYP2E1) and dapsone (CYP3A1) was administered orally on eighth- or fifteenth-day to rats pre-treated with DHP intragastrically at a dose of 36 and 72mg/kg for one week and two weeks. The concentrations of probe drugs in plasma were estimated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Alongside, the effect of DHP on CYPs activity and mRNA expression levels were assayed in isolated rat liver microsomes and by real-time reverse transcription-polymerase chain reaction (RT-PCR), respectively. DHP had significant inducing effects on CYP1A2, 2C11, 2D2 and 2E1 with no effect on CYP3A1 in dose- and time-dependent manner, as revealed from the pharmacokinetic profiles of the probe drugs in rats. In-vitro microsomal activities and mRNA expression results were in good agreement with the in-vivo pharmacokinetic results. Collectively, the results unveiled that DHP is an inducer of rat hepatic CYP enzymes. Hence, intense attention should be paid when DHP is co-administered with drugs metabolized by CYP1A2, 2C11, 2D2 and 2E1, which might result in drug-drug interactions and therapeutic failure.

Pretreatment of Shaoyao Gancao Decoction () alters pharmacokinetics of intravenous paclitaxel in rats

OBJECTIVE

To investigate the effect of Shaoyao Gancao Decoction (, SGD) on the pharmacokinetics of intravenously administered paclitaxel in rats.

METHODS

Paclitaxel was intravenously administered to rats (3 mg/kg) with or without the concomitant administration of SGD (752 mg/kg, a single day or 14 consecutive days pretreatment). The paclitaxel in the serum was quantified using a simple and rapid ultra performance liquid chromatography (UPLC) method for the pharmacokinetic study. The pharmacokinetic parameters were calculated via a non-compartment model using the computer program DAS 2.0.

RESULTS

The pharmacokinetic parameters of paclitaxel were significantly altered in response to 14 consecutive days of pretreatment with SGD. The area under the curve (AUC_0-t, from 4 820±197 to 4 205±186 ng·mL^-1·^-1) and AUC_0-∞ (from 5 237±280 to 4 514±210 ng·mL^-1·^-1) significantly decreased in response to the 14-day pretreatment with SGD. The values of V_dss (L/kg) were 10.74±1.08 and 9.35±0.49, those of CL (L/kg) were 0.67±0.03 and 0.57±0.03 and the t_1/2 (h) values were 11.17±0.84 and 11.32±0.93, respectively, for the 14-day SGD pretreatment and intravenous paclitaxel alone. The AUC_0-t and AUC_0-∞ values decreased by 13% and 14% (P<0.01), respectively. The area under the curve decreased signifificantly (P<0.01), and the total clearance increased by 1.2-fold (P<0.01), after 14 consecutive days of pretreatment with SGD. A single-day pretreatment with SGD did not signifificantly affect the pharmacokinetic parameters of paclitaxel.

CONCLUSIONS

SGD administration for 14 consecutive days increased the metabolism of paclitaxel, while a 1-day pretreatment had little effect. The results would contribute important information to the study on interaction between Chinese medicines and chemotherapy and also help to utilize SGD better in the adjunctive therapy of cancer patients.

In vitro Effects of Four Native Brazilian Medicinal Plants in CYP3A4 mRNA Gene Expression, Glutathione Levels, and P-Glycoprotein Activity

Erythrina mulungu Benth. (Fabaceae), Cordia verbenacea A. DC. (Boraginaceae), Solanum paniculatum L. (Solanaceae) and Lippia sidoides Cham. (Verbenaceae) are medicinal plant species native to Brazil shortlisted by the Brazilian National Health System for future clinical use. However, nothing is known about their effects in metabolic and transporter proteins, which could potentially lead to herb-drug interactions (HDI). In this work, we assess non-toxic concentrations (100 μg/mL) of the plant infusions for their in vitro ability to modulate CYP3A4 mRNA gene expression and intracellular glutathione levels in HepG2 cells, as well as P-glycoprotein (P-gp) activity in vincristine-resistant Caco-2 cells (Caco-2 VCR). Their mechanisms of action were further studied by measuring the activation of human pregnane X receptor (hPXR) in transiently co-transfected HeLa cells and the inhibition of γ-glutamyl transferase (GGT) in HepG2 cells. Our results show that P-gp activity was not affected in any case and that only Solanum paniculatum was able to significantly change CYP3A4 mRNA gene expression (twofold decrease, p < 0.05), this being correlated with an antagonist effect upon hPXR (EC50 = 0.38 mg/mL). Total intracellular glutathione levels were significantly depleted by exposure to Solanum paniculatum (-44%, p < 0.001), Lippia sidoides (-12%, p < 0.05) and Cordia verbenacea (-47%, p < 0.001). The latter plant extract was able to decrease GGT activity (-48%, p < 0.01). In conclusion, this preclinical study shows that the administration of some of these herbal medicines may be able to cause disturbances to metabolic mechanisms in vitro. Although Erythrina mulungu appears safe in our tests, active pharmacovigilance is recommended for the other three species, especially in the case of Solanum paniculatum.

Nerolidol: A Sesquiterpene Alcohol with Multi-Faceted Pharmacological and Biological Activities

Nerolidol (3,7,11-trimethyl-1,6,10-dodecatrien-3-ol) is a naturally occurring sesquiterpene alcohol that is present in various plants with a floral odor. It is synthesized as an intermediate in the production of (3E)-4,8-dimethy-1,3,7-nonatriene (DMNT), a herbivore-induced volatile that protects plants from herbivore damage. Chemically, nerolidol exists in two geometric isomers, a trans and a cis form. The usage of nerolidol is widespread across different industries. It has been widely used in cosmetics (e.g., shampoos and perfumes) and in non-cosmetic products (e.g., detergents and cleansers). In fact, U.S. Food and Drug Administration (FDA) has also permitted the use of nerolidol as a food flavoring agent. The fact that nerolidol is a common ingredient in many products has attracted researchers to explore more medicinal properties of nerolidol that may exert beneficial effect on human health. Therefore, the aim of this review is to compile and consolidate the data on the various pharmacological and biological activities displayed by nerolidol. Furthermore, this review also includes pharmacokinetic and toxicological studies of nerolidol. In summary, the various pharmacological and biological activities demonstrated in this review highlight the prospects of nerolidol as a promising chemical or drug candidate in the field of agriculture and medicine.

Quality and safety of herbal medical products: regulation and the need for quality assurance along the value chains

Herbal medicines and products derived from them are a diverse group of products for which different (and often limited) levels of evidence are available. As importantly, such products generally vary in their composition and are at the end of an often poorly understood value chain, which often links producers in biodiversity rich countries with the large markets in the North. This paper discusses the current regulatory framework of such herbal medical products (with a focus on the UK) and using examples from our own metabolomic research on Curcumal longa L. (turmeric, Zingiberaceae) how value chains impact on the composition and quality (and thus the safety) of such products. Overall, our recent research demonstrates the need for studying the links between producers and consumers of commodities produced in provider countries and that plant metabolomics offer a novel way of assessing the chemical variability along a value chain.

Effects of notoginsenoside R1 on CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2 activities in rats by cocktail probe drugs

CONTEXT

Notoginsenoside R1 (NGR1) is the main component with cardiovascular activity in Panax notoginseng (Burk.) F. H. Chen, an herbal medicine that is widely used to enhance blood circulation and dissipate blood stasis.

OBJECTIVE

The objective of this study is to investigate NGR1's effects on CYP1A2, CYP2C11, CYP2D1, and CYP3A1/2 activities in rats in vivo through the use of the Cytochrome P450 (CYP450) probe drugs.

MATERIALS AND METHODS

After pretreatment with NGR1 or physiological saline, the rats were administered intraperitoneally with a mixture solution of cocktail probe drugs containing caffeine (10 mg/kg), tolbutamide (15 mg/kg), metoprolol (20 mg/kg), and dapsone (10 mg/kg). The bloods were then collected at a set of time-points for the ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analysis.

RESULTS

NGR1 was shown to exhibit an inhibitory effect on CYP1A2 by increased caffeine Cmax (43.13%, p < 0.01) and AUC0 - ∞ (40.57%, p < 0.01), and decreased CL/F (62.16%, p < 0.01) in the NGR1-treated group compared with those of the control group, but no significant changes in pharmacokinetic parameters of tolbutamide, metoprolol, and dapsone were observed between the two groups, indicating that NGR1 had no effects on rat CYP2C11, CYP2D1, and CYP3A1/2.

DISCUSSION AND CONCLUSION

When NGR1 is co-administered with drugs that are metabolized by CYP1A2, the pertinent potential herb-drug interactions should be monitored.

Estimation of the binding modes with important human cytochrome P450 enzymes, drug interaction potential, pharmacokinetics, and hepatotoxicity of ginger components using molecular docking, computational, and pharmacokinetic modeling studies

Ginger is one of the most commonly used herbal medicines for the treatment of numerous ailments and improvement of body functions. It may be used in combination with prescribed drugs. The coadministration of ginger with therapeutic drugs raises a concern of potential deleterious drug interactions via the modulation of the expression and/or activity of drug-metabolizing enzymes and drug transporters, resulting in unfavorable therapeutic outcomes. This study aimed to determine the molecular interactions between 12 main active ginger components (6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, 10-shogaol, ar-curcumene, β-bisabolene, β-sesquiphelandrene, 6-gingerdione, (-)-zingiberene, and methyl-6-isogingerol) and human cytochrome P450 (CYP) 1A2, 2C9, 2C19, 2D6, and 3A4 and to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the 12 ginger components using computational approaches and comprehensive literature search. Docking studies showed that ginger components interacted with a panel of amino acids in the active sites of CYP1A2, 2C9, 2C19, 2D6, and 3A4 mainly through hydrogen bond formation, to a lesser extent, via π-π stacking. The pharmacokinetic simulation studies showed that the [I]/[Ki ] value for CYP2C9, 2C19, and 3A4 ranged from 0.0002 to 19.6 and the R value ranged from 1.0002 to 20.6 and that ginger might exhibit a high risk of drug interaction via inhibition of the activity of human CYP2C9 and CYP3A4, but a low risk of drug interaction toward CYP2C19-mediated drug metabolism. Furthermore, it has been evaluated that the 12 ginger components possessed a favorable ADMET profiles with regard to the solubility, absorption, permeability across the blood-brain barrier, interactions with CYP2D6, hepatotoxicity, and plasma protein binding. The validation results showed that there was no remarkable effect of ginger on the metabolism of warfarin in humans, whereas concurrent use of ginger and nifedipine exhibited a synergistic effect on platelet aggregation in humans. Moreover, ginger components showed a rapid half-life and no to low toxicity in humans. Taken together, this study shows that ginger components may regulate the activity and expression of various human CYPs, probably resulting in alterations in drug clearance and response. More studies are warranted to identify and confirm potential ginger-drug interactions and explore possible interactions of ginger with human CYPs and other functionally important proteins, to reduce and avoid side effects induced by unfavorable ginger-drug interactions.

Systematic review of the incidence of herbal drug-induced liver injury in Korea

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal drugs have been generally believed to be safe, based on the natural sources and long clinical experience. With the increasing use of herbal medicine worldwide, the potential toxicity of herbal drugs, especially drug-induced liver injury (DILI), frequently becomes a medical issue. This study was aimed to estimate the incidence of DILI following herbal drug consumption in Korea

METHODS AND MATERIALS

A literature search for herbal DILI in eight databases, including PubMed, Medline, the Cochrane Library, EMBASE, and four Korean electronic databases.

RESULTS

Six studies (three prospective and three retrospective) met the necessary criteria for assessment of the risk of DILI following herbal medicine exposure. The total number of participants in the six studies was 1699 (756 males and 943 females), and the incidence of herbal DILI varied from 0 to 1.92 among them. Total incidence of herbal DILI was 0.71% (12 patients with herbal DILI), and it was significantly higher in male (1.32%) than female (0.21%) respectively (p<0.01). All of the patients that experienced DILI concomitantly ingested herbal medicine and conventional drugs.

CONCLUSIONS

This result showed the comprehensive data indicating the incident risk of hepatotoxicity in patients using herbal drugs in Korea, and presented the possibility of increased risk for the DILI by concurrent administration of herbal and conventional medicines.

Pharmacokinetic interactions of herbs with cytochrome p450 and p-glycoprotein

The concurrent use of drugs and herbal products is becoming increasingly prevalent over the last decade. Several herbal products have been known to modulate cytochrome P450 (CYP) enzymes and P-glycoprotein (P-gp) which are recognized as representative drug metabolizing enzymes and drug transporter, respectively. Thus, a summary of knowledge on the modulation of CYP and P-gp by commonly used herbs can provide robust fundamentals for optimizing CYP and/or P-gp substrate drug-based therapy. Herein, we review ten popular medicinal and/or dietary herbs as perpetrators of CYP- and P-gp-mediated pharmacokinetic herb-drug interactions. The main focus is placed on previous works on the ability of herbal extracts and their phytochemicals to modulate the expression and function of CYP and P-gp in several in vitro and in vivo animal and human systems.

Effects of Guanxinning injection on rat cytochrome P450 isoforms activities in vivo and in vitro

1. We aimed to investigate the regulatory effects of Guanxinning injection (GXNI) on activities of cytochrome P1A2 (CYP1A2), CYP2C11, CYP2D1 and CYP3A1/2 by probe drugs in rats in vivo and in vitro. 2. GXNI-treated and blank control groups were administered GXNI and physiological saline by caudal vein for 14 days consecutively, then they were given the probe drugs of caffeine (10 mg/kg), tolbutamide (10 mg/kg), metoprolol (20 mg/kg) and dapsone (10 mg/kg) by intraperitoneal injection. The blood samples were collected at different times for ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. Changes of the pharmacokinetics parameters between the GXNI-treated and the blank control groups were used to evaluate the effects of GXNI on the four CYP450 isoforms in rats in vivo. After blood collection, the livers of rats were taken and made microsomes for in vitro tests. The relevant metabolites of phenacetin, tolbutamide, dextromethorphan and testosterone were analyzed quantitatively by high-performance liquid chromatography (HPLC) after microsome incubation. The statistical differences between the two groups were observed to detect the effects of GXNI on the four CYP450 isoforms in rats in vitro. 3. The in vivo and in vitro results demonstrated that GXNI could induce CYP1A2 activity in rats, but had no significant effects on CYP2C11, CYP2D1 and CYP3A1/2.

Updates on the clinical evidenced herb-warfarin interactions

Increasing and inadvertent use of herbs makes herb-drug interactions a focus of research. Concomitant use of warfarin, a highly efficacious oral anticoagulant, and herbs causes major safety concerns due to the narrow therapeutic window of warfarin. This paper presents an update overview of clinical findings regarding herb-warfarin interaction, highlighting clinical outcomes, severity of documented interactions, and quality of clinical evidence. Among thirty-eight herbs, Cannabis, Chamomile, Cranberry, Garlic, Ginkgo, Grapefruit, Lycium, Red clover, and St. John's wort were evaluated to have major severity interaction with warfarin. Herbs were also classified on account of the likelihood of their supporting evidences for interaction. Four herbs were considered as highly probable to interact with warfarin (level I), three were estimated as probable (level II), and ten and twenty-one were possible (level III) and doubtful (level IV), respectively. The general mechanism of herb-warfarin interaction almost remains unknown, yet several pharmacokinetic and pharmacodynamic factors were estimated to influence the effectiveness of warfarin. Based on limited literature and information reported, we identified corresponding mechanisms of interactions for a small amount of “interacting herbs.” In summary, herb-warfarin interaction, especially the clinical effects of herbs on warfarin therapy should be further investigated through multicenter studies with larger sample sizes.

Perceptions of benefit of complementary therapy use among people with diabetes and cardiovascular disease

BACKGROUND

Little is known about why and how people with type 2 diabetes and cardiovascular disease (CVD) use CAM, or of the perceived benefits of CAM use. The CAMELOT study explored care-seeking, self-management, costs, barriers and benefits of CAM use among this population. We report here on CAM used for treatment of diabetes and CVD, and non-clinical outcomes of CAM use.

METHODS

Data were collected in 2009-2010 via in-depth interviews (n = 69) and a self-report questionnaire (n = 2,915) among people with diabetes and/or CVD, throughout an Australian state. Analysis included contingency tables, chi-square analysis and thematic coding of interview and long answer survey data.

RESULTS

CAM use was generally part of a multi-component approach to chronic condition management. Choice of CAM practitioners and products varied and included CAM not usually associated with diabetes or CVD treatment, such as massage or manipulative therapies (44%). Most survey respondents perceived that CAM consultations resulted in symptom relief, improved general health and increased knowledge, understanding and confidence in condition management. Few people reported that they experienced any side effects from CAM. Economic barriers were significant in limiting access to CAM.

CONCLUSION

More research is required to understand how the appropriate use and perceived benefits of CAM can be reinforced by stronger interaction or integration with mainstream health service delivery for chronic condition management and illness prevention.

Hypericum perforatum: pharmacokinetic, mechanism of action, tolerability, and clinical drug-drug interactions

Hypericum perforatum (HP) belongs to the Hypericaceae family and is one of the oldest used and most extensively investigated medicinal herbs. The medicinal form comprises the leaves and flowering tops of which the primary ingredients of interest are naphthodianthrones, xanthones, flavonoids, phloroglucinols (e.g. hyperforin), and hypericin. Although several constituents elicit pharmacological effects that are consistent with HP's antidepressant activity, no single mechanism of action underlying these effects has thus far been found. Various clinical trials have shown that HP has a comparable antidepressant efficacy as some currently used antidepressant drugs in the treatment of mild/moderate depression. Interestingly, low-hyperforin-content preparations are effective in the treatment of depression. Moreover, HP is also used to treat certain forms of anxiety. However, HP can induce various cytochrome P450s isozymes and/or P-glycoprotein, of which many drugs are substrates and which are the main origin of HP-drug interactions. Here, we analyse the existing evidence describing the clinical consequence of HP-drug interactions. Although some of the reported interactions are based on findings from in vitro studies, the clinical importance of which remain to be demonstrated, others are based on case reports where causality can, in some cases, be determined to reveal clinically significant interactions that suggest caution, consideration, and disclosure of potential interactions prior to informed use of HP.

Vietnamese traditional medicine from a pharmacist's perspective

Traditional medicine plays an important role in the healthcare system of Vietnam. Vietnamese traditional medicine (VTM) is underpinned by the oriental philosophy and theory of healing. VTM is largely influenced by traditional Chinese medicine, but differs to a certain extent. VTM is largely not evidence-based from a clinical perspective but subclinical research data from the past decades support the traditional use of many herbal VTM drugs. For safe use, knowledge of the occurrence of adverse reactions and herb-drug interactions is necessary. The Vietnamese government supports further development of VTM in a scientific way and integration of VTM with Western medicine. This article first gives an overview of the general aspects of VTM (historical perspective, regulatory aspects, comparison with traditional Chinese medicine, philosophical background, the Vietnamese market situation, quality assurance and formulations), and subsequently focuses on its safe and effective use in Vietnamese clinical pharmacy and medical practice.

A prospective study on the safety of herbal medicines, used alone or with conventional medicines

ETHNOPHARMACOLOGICAL RELEVANCE

Along with increase of herbal medicine use worldwide, the safety of traditional herbal medicines frequently becomes a medical issue.

AIM OF THE STUDY

This study aimed to investigate the incidence of herbal medicine-induced adverse effects on liver functions.

SUBJECTS AND METHODS

A prospective study was performed with 313 inpatients (87 male and 226 female) receiving herbal prescriptions during hospitalization. The patients were classified into two groups based on their treatments: one group received herbal medicines only (57 patients), and another received herbal and conventional medicines concurrently (256 patients). All patients were given liver and renal function tests at the start of hospitalization (baseline) and at approximately 2-week intervals thereafter, until discharge.

RESULTS

Six of the 313 patients showed abnormal liver function without related clinical symptoms (1.9%, 95% CI 0.38-3.41); none of the patients in the herbal group had abnormal result in liver function tests (0% of 57 patients) while all six had received a combination of herbal and conventional medicines (2.3% of 256 patients, 95% CI 0.46-4.14).

CONCLUSION

Our findings indicate that herbal drugs used alone are relatively safe, but the risk for adverse reactions may increase when herbal and conventional drugs are taken concurrently.

Herbal medicine: a survey of use in Nigerian presurgical patients booked for ambulatory anaesthesia

BACKGROUND

Utilization of herbal medicines in the preoperative period by Nigerian patients booked for day case surgery has not been explored.

METHODS

Cross-sectional survey of 60 patients presenting for day-case surgery at a tertiary healthcare institution over a 3-week period in August 2011 was conducted. Using a structured questionnaire, inquiries were made concerning use of herbal medicines in the immediate preoperative period. Socio-demographic characteristics, information on use of concurrent medical prescriptions, types of herbs used, reasons for use, perceived side effects and perceived efficacy were obtained. Data were evaluated using descriptive statistics and Chi-square.

RESULTS

Fifty-two (86.7%) were American Society of Anesthesiologists (ASA) class 1 while 8 (13%) were ASA 2. Most patients (86.7%) had their procedures done under local infiltration with monitored anaesthesia care (MAC), while 5.0% and 8.3% had their procedures done under regional and general anaesthesia, respectively. About 48.3% of respondents were on concurrent medical prescriptions while 51.7% were not. Forty percent (40%) of patients admitted to use of herbal medicine, all by the oral route, in the immediate perioperative period; 87.5% did not inform their doctor of their herbal use. Types of herbs used included 'dogonyaro', 'agbo', 'nchanwu', and Tahitian noni. Treatment of malaria was commonest reason for use in 29.2% of patients, while cough and concurrent surgical condition were reasons given by 12.5% of patients, respectively. Seventy-nine percent (79.2%) of patients considered their herbal medications effective. Perceived side effects of herbal medication (16.6%) included fever, waist pain and intoxication. There were no variations in use between ASA 1 and ASA 2 patients and none between respondents on conventional medication against those that were not. Variables such as age less than 35 years, female gender, being married and being an urban dweller did not show any significant difference in use.

CONCLUSION

This survey revealed many patients were on one or more herbal preparations in the immediate preoperative period. In consideration of possible untoward drug interactions between conventional medication, herbal preparations and anaesthesia, doctors (especially anaesthetists) should routinely assess all patients booked to be anaesthetized, especially those for day case surgery. The authors recommend surveys with larger respondent numbers to determine prevalence of use and possible interactions between indigenous Nigerian herbs and anaesthesia.

Review of current and "omics" methods for assessing the toxicity (genotoxicity, teratogenicity and nephrotoxicity) of herbal medicines and mushrooms

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing use of traditional herbal medicines around the world requires more scientific evidence for their putative harmlessness. To this end, a plethora of methods exist, more or less satisfying. In this post-genome era, recent reviews are however scarce, not only on the use of new "omics" methods (transcriptomics, proteomics, metabonomics) for genotoxicity, teratogenicity, and nephrotoxicity assessment, but also on conventional ones.

METHODS

The present work aims (i) to review conventional methods used to assess genotoxicity, teratogenicity and nephrotoxicity of medicinal plants and mushrooms; (ii) to report recent progress in the use of "omics" technologies in this field; (iii) to underline advantages and limitations of promising methods; and lastly (iv) to suggest ways whereby the genotoxicity, teratogenicity, and nephrotoxicity assessment of traditional herbal medicines could be more predictive.

RESULTS

Literature and safety reports show that structural alerts, in silico and classical in vitro and in vivo predictive methods are often used. The current trend to develop "omics" technologies to assess genotoxicity, teratogenicity and nephrotoxicity is promising but most often relies on methods that are still not standardized and validated.

CONCLUSION

Hence, it is critical that toxicologists in industry, regulatory agencies and academic institutions develop a consensus, based on rigorous methods, about the reliability and interpretation of endpoints. It will also be important to regulate the integration of conventional methods for toxicity assessments with new "omics" technologies.

Herbal medicines: can we do without pharmacologist?

The increase of herbal medicine use led many scientists to contribute to the research in this field. Also a few pharmacologists, after an initial phase of correct criticisms, today recognize the possibility of investigating the scientific value of medicinal products composed essentially of vegetable extracts. However, it is logical to pose the questions: (i) is there a role for the pharmacologist in herbal medicine (or phytotherapy)? (ii) can we do without pharmacologists’? First, two worlds—drug researchers (pharmacologists) and herbal medicines—yesterday appearing in opposition, are today closer and it is not unusual to read scientific works describing herbal extracts in journals traditionally dedicated to the study of synthetic drugs. Second, clinical application of herbal medicines is evaluable through the methods of modern clinical pharmacology. Efficacy and safety of medicinal plants represent naturally the object of interest for the pharmacologist and it is surely this aspect which gives the most important information on herbal medicine use. Many plants have been studied and results published showing, one time good or another poor, efficacy. Safety aspects of some of the most frequently used plants are now well known. For example, today we learn to use hypericum and we do not give it to patients taking other drugs because the interactions of hypericum with them. Contraindications of other plants, often represented by interactions with drugs, are finally known (Ginkgo biloba and drugs acting on blood coagulation). In conclusion, antagonistic behavior of pharmacologists versus herbal medicines is not useful. On the contrary, modern phytotherapy needs the contribution of researchers usually trained to evaluate efficacy and safety of medicinals.

Effects of Flos carthami on CYP2D6 and on the Pharmacokinetics of Metoprolol in Rats

Flos carthami is a traditional Chinese herbal medicine. Clinically, the Flos carthami Injection has been used concomitantly with other Western drugs and may be used concomitantly with β-blockers, such as metoprolol, to treat cerebrovascular and coronary heart diseases, in China. Metoprolol is a CYP2D6 substrate and is predominantly metabolized by this isozyme. However, we do not know whether there is an effect of Flos carthami on CYP2D6 and the consequences of such an effect. Concern is raised regarding the possible herb-drug interaction. In this report, the effects of Flos carthami on the activity of CYP2D6 in vivo and in vitro and on the pharmacokinetics of metoprolol, in rats, are investigated. To assess the inhibitory potency of Flos carthami, the concentration associated with 50% inhibition (IC₅₀) of dextromethorphan metabolism was determined based on the concentration-inhibition curves. The inhibitory effect of Flos carthami on CYP2D6 was also compared with cimetidine in vitro. Flos carthami could significantly inhibit CYP2D6 in rats both in vitro and in vivo (P < .05) and could slow down the metabolic rate of metoprolol as suggested by prolonged t_1/2 (67.45%), by increased C_max (74.51%) and AUC_0−∞ (76.89%). These results suggest that CYP2D6 is a risk factor when Flos carthami is administered concomitantly with metoprolol or other CYP2D6 substrates.

Adverse reactions to complementary medicines: the Australian pharmacy experience

OBJECTIVES

The primary aim was to determine the prevalence of adverse reactions to over-the-counter complementary medicines and their severity, as described by consumers. Secondary aims were to identify consumers' reporting behaviours and understanding of the AUST L designation on product labels.

METHODS

An anonymous, self-administered survey was completed by randomly selected pharmacy customers at 60 community pharmacy locations between August 2008 and February 2009.

KEY FINDINGS

Of the 1121 survey participants (response rate 62%), 72% had used a complementary medicine product in the previous 12 months, and 7% of this group (n = 55) reported having experienced an adverse reaction at some time. Of these, 71% described the reaction as mild and not requiring treatment, 22% as moderate and/or requiring advice from a healthcare professional and 7% (n = 4) described it as severe and requiring hospitalisation. If they were to report the reaction, it was most commonly to a medical practitioner. Most (88%) of complementary medicine consumers had never noticed the term 'AUST L'.

CONCLUSIONS

Complementary medicines are widely used by pharmacy customers. Adverse reactions to these products are under-reported to healthcare authorities. Most adverse reactions are mild and serious reactions are rare. Customers have little awareness of the designation AUST L.

Use and safety perception of herbal remedies in patients with liver/biliary tract disorders: an Italian study

BACKGROUND

Use of herbal remedies (HR) has increased in the general population, particularly among patients with chronic diseases. Marketing of HR is usually regulated by imperfect standards, and the reporting of HR-related adverse reactions has increased. Studies assessing prevalence of HR use among patients with liver/biliary tract disorders are limited and no data are available in Italy. Aims of this study were to assess the prevalence of HR use, the clinical and demographic variables of HR users, and to evaluate their safety perception about HR.

STUDY

From October 1, 2007 to April 30, 2008, 231 consecutive patients attending the Liver Disease Unit clinic at Sant'Andrea Hospital, II Faculty of Medicine "La Sapienza" Rome, were interviewed using an ad hoc developed questionnaire. The questionnaire addressed the following items: demographic and clinical characteristics, use of conventional therapy, use of HR and safety perception. Data were expressed as mean (+/-SD) or number/total, and evaluated by student t and chi2 tests; univariate analysis and multivariate logistic regression (MLR) were conducted.

RESULTS

Prevalence of HR use was 35.5%. HR use was more common among women (P=0.01), and in patients attending sports activity (P=0.03). 72% of patients using HR had never considered potentially harmful HR-side effects or interactions. Sixty-seven percent used HR in addition to conventional therapy.

CONCLUSIONS

More than a third of patients attending Liver/Biliary Disorders Clinic uses HR. Misconceptions about HR safety is common.

Spontaneously reported adverse reactions in association with complementary and alternative medicine substances in Sweden

PURPOSE

Although the safety information is limited, use of complementary and alternative medicine (CAM) products is not without risks. Spontaneous reporting systems may be used in the surveillance of these products. We describe the pattern of spontaneously reported CAM related adverse reactions submitted to the Swedish Medical Products Agency (MPA) and highlight areas of safety concern.

METHODS

All adverse reactions spontaneously reported to MPA between 1987 and 2006, where at least one CAM substance was a suspected agent, were scrutinised. From each report information about the patient, adverse reaction/s, drug treatment/s, dosage, time relationship and outcome was retrieved.

RESULTS

Among a total of 64 493 reports, 778 reports concerned 967 suspected adverse reactions related to 175 different CAM products. The main distribution of suspected adverse reactions was: urticaria (8.3%), exanthema (7.4%) and contact dermatitis (5.7%). The most reported CAM substances were purple coneflower (Echinacea purpurea) (8.1%), purple coneflower + siberian ginseng (Eleutherococcus senticosus) + malabar nut (Adhatoda vasica) (7.3%) and ginkgo leaf (Ginkgo biloba) (6.7%). In 221 reports, at least one reaction was categorised as serious, the most frequent being pulmonary embolism (1.7%), mixed liver reaction (2.8%), and anaphylactic reaction (2.0%). Eleven of the serious adverse reactions had a fatal outcome.

CONCLUSIONS

CAM substances were associated with a variety of adverse reactions. Some of these have previously been unrecognised or poorly documented and suggest further investigations. By stimulating the reporting of adverse reactions of CAM products, the signal detection power of the spontaneous reporting system may increase further.

Effects of Cecropia pachystachya and Larrea divaricata aqueous extracts in mice

Our studies were performed to investigate the effects of the aqueous extracts of Cecropia pachystachya and Larrea divaricata. These plants are used in folkloric medicine in infusion and were administered orally (0.76 g/kg) to male Albino Swiss mice for 16 days, on drink intake, organ weight/body weight (OW/BW × 100) ratio, histology, broqueoalveolar fluid (BALF) and elevated plus-maze (EPM). Feeding as well as body weight were unaffected by the consumption of these extracts. There were no signs of toxicity in BALF, morbidity or mortality during the study. C. pachystachya caused an increase in relative kidney OW/BW (p ≤ .05 vs control). The macroscopic and microscopic morphologic analyses of the organs were not altered by administration of these plants. A non-anxiolytic-like activity of an aqueous extract prepared from the leaves of C. pachystachya and L. divaricata in EPM was observed. We conclude that the crude aqueous extracts of leaves tested on mice orally did not produce signs of toxicity or behavioral changes in routine histological and clinical evaluation. However, knowledge of the biological activity of many herbal medicine used in Latin American is still deficient and more studies will be needed to elucidate the possible toxic effects.

Herb-drug interactions with St John's wort (Hypericum perforatum): an update on clinical observations

St John's wort (SJW) extracts, prepared from the aerial parts of Hypericum perforatum, contain numerous pharmacologically active ingredients, including naphthodianthrones (e.g., hypericin and its derivatives), phloroglucinols derivatives (e.g., hyperforin, which inhibits the reuptake of a number of neurotransmitters, including serotonin), and flavonoids. Such extracts are widely used for the treatment of mild-to-moderate depression. As a monotherapy, SJW has an encouraging safety profile. However, relevant and, in some case, life-threatening interactions have been reported, particularly with drugs which are substrate of cytochrome P450 and/or P-glycoprotein. Well-documented SJW interactions include (1) reduced blood cyclosporin concentration, as suggested by multiple case reports as well as by clinical trials, (2) serotonin syndrome or lethargy when SJW was given with serotonin reuptake inhibitors, (3) unwanted pregnancies in women while using oral contraceptives and SJW, and (4) reduced plasma drug concentration of antiretroviral (e.g., indinavir, nevirapine) and anticancer (i.e., irinotecan, imatinib) drugs. Hyperforin, which is believed to contribute to the antidepressant action of St John's wort, is also strongly suspected to be responsible of most of the described interactions.

Surveillance of suspected adverse reactions to natural health products in Italy

PURPOSE

Natural health products are promoted to the public as equally or more effective and less toxic than conventional drugs. However, some 'natural' medicines, and in particular some herbal medicines, are known to have adverse effects. The Italian Pharmacovigilance System, in charge of the Italian Medicines Agency, collects spontaneous reports only for registered drugs. The awareness of the need of surveillance of the safety of natural health products has stimulated the implementation of a suspected adverse reaction reporting system in Italy. The system has been set up by the Italian National Institute of Health.

METHODS

An ad hoc reporting form can be downloaded from different institutional web sites. Voluntary reports of suspected adverse reactions are sent to the National Institute of Health and are evaluated by a multidisciplinary group of experts.

RESULTS

From April 2002 to March 2007, 233 spontaneous reports of suspected adverse reactions to natural health products were collected. A large proportion of suspected adverse reactions were serious: hospitalization was reported in 35% of forms; 6% reported life threatening clinical events and two fatal events were notified. About 50% of suspected adverse reactions were related to gastrointestinal, skin, psychiatric and nervous system disorders. Mainly herbal products (66%) were involved. Twenty-one cases of hepatitis of various seriousness were reported. Twenty-one reports were associated with 27 homeopathic preparations, mostly preparations containing mixtures of substances. Fourteen reports regarded suspected reactions to products containing propolis.

CONCLUSION

Safety and efficacy of 'natural' medicines have not been thoroughly investigated. It is important to improve communication with the public on safety issues. Encouraging spontaneous reporting can contribute to improve awareness among health personnel and patients about the benefit-harm profile of these remedies.