Possible influences of ginseng on the pharmacokinetics and pharmacodynamics of warfarin in rats

The influence of Javanese turmeric (Curcuma xanthorrhiza) on the pharmacokinetics of warfarin in rats with single and multiple-dose studies

CONTEXT

Co-administration between warfarin (WF) and Curcuma xanthorrhiza Roxb. (Zingiberaceae) (CX) is found in Indonesian patients and need to be evaluated.

OBJECTIVE

This study assesses the effect of concomitant administration of CX extract on the pharmacokinetics of WF in rats.

MATERIALS AND METHODS

Wistar rats were divided into 4 groups (n = 6) and administered with 2% Pulvis Gummi Arabicum (PGA, control), fluconazole (FZ, 6 mg/kg), CX-1 (6 mg/kg) or CX-2 (18 mg/kg BW) for 7 days. For the single-dose study, at the 8th day, WF (1 mg/kg) was administered to all groups and blood samples were taken from 0.25 to 72 h. For the multiple-dose study, daily dose of WF was administered to all groups of rats and at the 7th to 9th day, the rats were treated with PGA, CX-1, CX-2 and FZ. Blood samples were withdrawn daily at 4 h after administration of WF from the 1st to 11th day.

RESULTS

The area under the curve (AUC) of R- and S-WF in the CX-2 group was a significantly higher value compared to the control (77.54 vs. 35.27 mg.h/L for R-WF and 316.26 vs. 40.16 mg.h/L for S-WF; p < 0.05; Kruskal-Wallis method). The CX-2 administration also caused the increasing in the concentration level of R-WF (16%) and S-WF (27%) from the 7th to 9th day of administration.

DISCUSSION AND CONCLUSIONS

The CX administration in a higher dose caused alteration on WF pharmacokinetics suggesting the need for clinical evaluation of the interaction between CX and WF.

Sensitivity of turtles to anticoagulant rodenticides: Risk assessment for green sea turtles (Chelonia mydas) in the Ogasawara Islands and comparison of warfarin sensitivity among turtle species

Although anticoagulant rodenticides (ARs) are effectively used for the control of invasive rodents, nontarget species are also frequently exposed to ARs and secondary poisonings occur widely. However, little data is available on the effects of ARs, especially on marine organisms. To evaluate the effects of ARs on marine wildlife, we chose green sea turtles (Chelonia mydas), which are one of the most common marine organisms around the Ogasawara islands, as our primary study species. The sensitivity of these turtles to ARs was assessed using both in vivo and in vitro approaches. We administered 4 mg/kg of warfarin sodium either orally or intravenously to juvenile green sea turtles. The turtles exhibited slow pharmacokinetics, and prolongation of prothrombin time (PT) was observed only with intravenous warfarin administration. We also conducted an in vitro investigation using liver microsomes from green sea turtles, and two other turtle species (softshell turtle and red-eared slider) and rats. The cytochrome P450 metabolic activity in the liver of green sea turtles was lower than in rats. Additionally, vitamin K epoxide reductase (VKOR), which is the target enzyme of ARs, was inhibited by warfarin in the turtles at lower concentration levels than in rats. These data indicate that turtles may be more sensitive to ARs than rats. We expect that these findings will be helpful for sea turtle conservation following accidental AR-broadcast incidents.

Ginsenosides for cardiovascular diseases; update on pre-clinical and clinical evidence, pharmacological effects and the mechanisms of action

Cardiovascular disease (CVD) remains the major cause of death worldwide, accounting for almost 31% of the global mortality annually. Several preclinical studies have indicated that ginseng and the major bioactive ingredient (ginsenosides) can modulate several CVDs through diverse mechanisms. However, there is paucity in the translation of such experiments into clinical arena for cardiovascular ailments due to lack of conclusive specific pathways through which these activities are initiated and lack of larger, long-term well-structured clinical trials. Therefore, this review elaborates on current pharmacological effects of ginseng and ginsenosides in the cardiovascular system and provides some insights into the safety, toxicity, and synergistic effects in human trials. The review concludes that before ginseng, ginsenosides and their preparations could be utilized in the clinical treatment of CVDs, there should be more preclinical studies in larger animals (like the guinea pig, rabbit, dog, and monkey) to find the specific dosages, address the toxicity, safety and synergistic effects with other conventional drugs. This could lead to the initiation of large-scale, long-term well-structured randomized, and placebo-controlled clinical trials to test whether treatment is effective for a longer period and test the efficacy against other conventional therapies.

Physiologically Based Pharmacokinetic Models Predicting Renal and Hepatic Concentrations of Industrial Chemicals after Virtual Oral Doses in Rats

Recently developed high-throughput in vitro assays in combination with computational models could provide alternatives to animal testing. The purpose of the present study was to model the plasma, hepatic, and renal pharmacokinetics of approximately 150 structurally varied types of drugs, food components, and industrial chemicals after virtual external oral dosing in rats and to determine the relationship between the simulated internal concentrations in tissue/plasma and their lowest-observed-effect levels. The model parameters were based on rat plasma data from the literature and empirically determined pharmacokinetics measured after oral administrations to rats carried out to evaluate hepatotoxic or nephrotic potentials. To ensure that the analyzed substances exhibited a broad diversity of chemical structures, their structure-based location in the chemical space underwent projection onto a two-dimensional plane, as reported previously, using generative topographic mapping. A high-throughput in silico one-compartment model and a physiologically based pharmacokinetic (PBPK) model consisting of chemical receptor (gut), metabolizing (liver), central (main), and excreting (kidney) compartments were developed in parallel. For 159 disparate chemicals, the maximum plasma concentrations and the areas under the concentration-time curves obtained by one-compartment models and modified simple PBPK models were closely correlated. However, there were differences between the PBPK modeled and empirically obtained hepatic/renal concentrations and plasma maximal concentrations/areas under the concentration-time curves of the 159 chemicals. For a few compounds, the lowest-observed-effect levels were available for hepatotoxicity and nephrotoxicity in the Hazard Evaluation Support System Integrated Platform in Japan. The areas under the renal or hepatic concentration-time curves estimated using PBPK modeling were inversely associated with these lowest-observed-effect levels. Using PBPK forward dosimetry could provide the plasma/tissue concentrations of drugs and chemicals after oral dosing, thereby facilitating estimates of nephrotoxic or hepatotoxic potential as a part of the risk assessment.

A study to evaluate herb-drug interaction underlying mechanisms: An investigation of ginsenosides attenuating the effect of warfarin on cardiovascular diseases

Warfarin and ginseng have been widely used in the treatment of cardiovascular diseases. However, the clinical safety and effectiveness of herb-drug combination treatment are still controversial. Therefore, it is very essential to probe the interaction between warfarin and ginseng. In this study, in vitro and in vivo study was carried out to demonstrate that whether there is an interaction between warfarin and ginsenosides (GS), which is the main component of ginseng. In vitro study showed that the adhesion ability between endothelial cells and matrigel/platelets was enhanced due to the up-regulating expression of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) proteins by treatment of warfarin+GS combination compared to warfarin/GS treatment alone. Moreover, GS could weaken the anticoagulation effect of warfarin in hyperlipemia rats owning to the increased expression levels of coagulation factors and hepatic cytochrome P450 enzymes in plasma after long-term co-administration of warfarin with GS. The results of both in vitro and in vivo study demonstrated that there is a serious interaction between warfarin and ginseng, which may deteriorate atherosclerosis and thrombosis after combined use of warfarin and GS.

Plasma and Hepatic Concentrations of Chemicals after Virtual Oral Administrations Extrapolated Using Rat Plasma Data and Simple Physiologically Based Pharmacokinetic Models

Only a small fraction of chemicals possesses adequate in vivo toxicokinetic data for assessing potential hazards. The aim of the present study was to model the plasma and hepatic pharmacokinetics of more than 50 disparate types of chemicals and drugs after virtual oral administrations in rats. The models were based on reported pharmacokinetics determined after oral administration to rats. An inverse relationship was observed between no-observed-effect levels after oral administration and chemical absorbance rates evaluated for cell permeability ( r = -0.98, p < 0.001, n = 17). For a varied selection of more than 30 chemicals, the plasma concentration curves and the maximum concentrations obtained using a simple one-compartment model (recently recommended as a high-throughput toxicokinetic model) and a simple physiologically based pharmacokinetic (PBPK) model (consisting of chemical receptor, metabolizing, and central compartments) were highly consistent. The hepatic and plasma concentrations and the hepatic and plasma areas under the concentration-time curves of more than 50 chemicals were roughly correlated; however, differences were evident between the PBPK-modeled values in livers and empirically obtained values in plasma. Of the compounds selected for analysis, only seven had the lowest observed effect level (LOEL) values for hepatoxicity listed in the Hazard Evaluation Support System Integrated Platform in Japan. For these seven compounds, the LOEL values and the areas under the hepatic concentration-time curves estimated using PBPK modeling were inversely correlated ( r = -0.78, p < 0.05, n = 7). This study provides important information to help simulate the high hepatic levels of potent hepatotoxic compounds. Using suitable PBPK parameters, the present models could estimate the plasma/hepatic concentrations of chemicals and drugs after oral doses using both PBPK forward and reverse dosimetry, thereby indicating the potential value of this modeling approach in predicting hepatic toxicity as a part of risk assessments of chemicals absorbed in the human body.

LC-MS based metabolic and metabonomic studies of Panax ginseng

INTRODUCTION

Panax ginseng has received much attention as a valuable health supplement with medicinal potential. Its chemical diversity and multiple pharmacological properties call for comprehensive methods to better understand the effects of ginseng and ginsenosides. Liquid chromatography-mass spectrometry (LC-MS) based metabonomic approaches just fit the purpose.

OBJECTIVE

Aims to give a review of recent progress on LC-MS based pharmacokinetic, metabolic, and phytochemical metabolomic studies of ginseng, and metabonomic studies of ginseng intervention effects.

METHODS

The review has four sections: the first section discusses metabolic studies of ginsenosides based on LC-MS, the second focuses on ginsenoside-drug interactions and pharmacokinetic interaction between herb compounds based on LC-MS, the third is phytochemical metabolomic studies of ginseng based on LC-MS, and the fourth deals with metabonomic studies of ginseng intervention effects based on LC-MS.

RESULTS

LC-MS based metabonomic research on ginseng include analysis of single ginsenoside and total ginsenosides. The theory of multi-components and multi-targeted mechanisms helps to explain ginseng effects.

CONCLUSION

LC-MS based metabonomics is a promising way to comprehensively assess ginseng. It is valuable for quality control and mechanism studies of ginseng.

Perioperative Herbal Supplement Use in Cancer Patients: Potential Implications and Recommendations for Presurgical Screening

BACKGROUND

Products made from botanicals that are used to maintain or improve health are known as herbal supplements, botanicals, or phytomedicines. Many herbs have a long history of use and claimed health benefits. However, many herbal supplements and botanicals have potent pharmacologic activity that can contribute to adverse effects and drug interactions. The use of herbal supplements by cancer patients in the perioperative period is common and consistent with the substantial increase in the use of alternative medical therapies.

METHODS

We reviewed the literature to examine the constituents, safety, pharmacokinetics, and pharmacodynamics of those herbal supplements that are predominantly used by cancer patients.

RESULTS

Different supplements possess antiplatelet activity, adversely interact with corticosteroids and central nervous system depressant drugs, have gastrointestinal manifestations, produce hepatotoxicity and nephrotoxicity, and produce additive effects when used with opioid analgesics.

CONCLUSIONS

With the increasing use of herbal supplements by cancer patients, surgical staff need to screen patients pre-surgically for use of these supplements. Clinical practice guidelines are needed for screening and prevention of herbal supplement usage to prevent potential adverse events that may arise from herbal medications taken alone or combined with conventional therapies during the perioperative period.

Global deregulation of ginseng products may be a safety hazard to warfarin takers: solid evidence of ginseng-warfarin interaction

Recent global deregulation of ginseng as the table food raises our concern about the possible ginseng-warfarin interaction that could be life-threatening to patients who take warfarin for preventing fatal strokes and thromboembolism while using ginseng products for bioenergy recovery. Here we show that quality-control ginsenosides, extracted from ginseng and containing its major active ingredients, produce dose- and time-dependent antagonism in rats against warfarin's anti-coagulation assessed by INR and rat thrombosis model. The interactions between ginsenosides and warfarin on thrombosis, pharmacokinetics, activities of coagulation factors and liver cytochrome P450 isomers are determined by using thrombosis analyzer, UPLC/MS/MS, ELISA and real-time PCR, respectively. The antagonism correlates well with the related pharmacokinetic interaction showing that the blood plateaus of warfarin reached by one-week warfarin administration are significantly reduced after three-week co-administration of warfarin with ginsenosides while 7-hydroxywarfarin is increased. The one-week warfarin and three-week warfarin-ginsenosides regimen result in restoring the suppressed levels by warfarin of the coagulating factors II, VII and protein Z, and significantly enhance activities of P450 3A4 and 2C9 that metabolize warfarin. The present study, for the first time, provides the solid evidence to demonstrate the warfarin-ginsenoside interaction, and warns the warfarin users and regulation authorities of the dangerous interaction.

Negligible Pharmacokinetic Interaction of Red Ginseng and Losartan, an Antihypertensive Agent, in Sprague-Dawley Rats

Red ginseng (RG) is one of the top selling herbal medicines in Korea, but is not recommended in hypertensive patients. In this study, the pharmacokinetic (PK) interaction between RG and losartan, an antihypertensive drug, was examined. RG was orally administered for 2 wk to male Sprague-Dawley (S-D) rats at either control (0), 0.5, 1, or 2 g/kg/d for 2 wk. After the last administration of RG and 30 min later, all animals were treated with 10 mg/kg losartan by oral route. In addition, some S-D rats were administered RG orally for 21 d at 2 g/kg followed by losartan intravenously (iv) at 10 mg/kg/d. Post losartan administration, plasma samples were collected at 5, 15, and 30 min and 1, 1.5, 2, 3, 6, 12, and 24 h. Plasma concentrations of losartan and E-3174, the active metabolite of losartan, were analyzed by a high-pressure liquid chromatography-tandem mass spectrometer system (LC-MS/MS). Oral losartan administration showed dose-dependent pharmacokinetics (PK) increase with time to maximum plasma, but this was not significant between different groups. There was no significant change in tmax with E-3174 PK. With iv losartan, pharmacokinetics showed elevation of area under the plasma concentration-time curve from time zero extrapolated to infinitity. There was not a significant change in AUCinf with E-3174 PK. Therefore, RG appeared to interfere with biotransformation of losartan, as RG exerted no marked effect on E-3174 PK in S-D rats. Data demonstrated that oral or iv treatment with losartan in rats pretreated with RG for 2 wk showed that losartan PK was affected but E-3174 PK remained unchanged among different dose groups. These results suggested that RG induces negligible influence on losartan and E-3174 PK in rats.

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.

Negligible pharmacokinetic interaction of red ginseng and antihypertensive agent amlodipine in Sprague-Dawley rats

Red ginseng (RG) is the top-selling functional food in Korea, but is not recommended for use in hypertensive patients. This study was performed to determine the pharmacokinetic (PK) interaction between RG and amlodipine, an antihypertensive drug. RG (0, 0.5, 1, or 2 g/kg/d) was administered orally for 2 wk, and then amlodipine (10 mg/kg) was given orally, to Sprague-Dawley (SD) rats. Blood was collected at 0.08, 0.25, 1, 1.5, 2, 3, 6, 12, and 24 h after amlodipine administration. In intravenous (iv) study, RG (0, 1, or 2 g/kg/d) was administered orally to SD rats for 2 wk, followed by amlodipine (2 mg/kg) intravenously (iv). Plasma concentrations of amlodipine were analyzed using a high-pressure liquid chromatography-tandem mass system (LC-MS/MS). Oral administration of amlodipine produced an increase of time to maximum plasma concentration (tmax: 2.6, 4.1, 8.3, and 8.9 h at 0, 0.5, 1, and 2 g/kg/d, respectively), and a decrease of maximum plasma concentration (Cmax: 278.5, 212.4, 232.1, and 238.7 ng/ml at 0, 0.5, 1, and 2 g/kg/d, respectively.). However, the area under the concentration-time curve from time 0 to 24 h measurable concentration (AUC0-24 h was 3487.4, 2895.4, 3158.2, and 3495 ng/h/ml at 0, 0.5, 1, and 2 g/kg/d respectively) was not significantly changed among the different dose groups. Administration of amlodipine iv produced no significant changes in the apparent terminal half-life, volume of distribution, and AUC0-24 hr among the different dose groups. These results suggest that RG induced negligible influence on amlodipine pharmacokinetically in rats.

Role of high mobility group box 1 in inflammatory disease: focus on sepsis

High mobility group box 1 (HMGB1) is a highly conserved, ubiquitous protein present in the nuclei and cytoplasm of nearly all cell types. In response to infection or injury, HMGB1 is actively secreted by innate immune cells and/or released passively by injured or damaged cells. Thus, serum and tissue levels of HMGB1 are elevated during infection, and especially during sepsis. Sepsis is a systemic inflammatory response to disease and the most severe complication of infections, and HMGB1 acts as a potent proinflammatory cytokine and is involved in delayed endotoxin lethality and sepsis. Furthermore, the targeting of HMGB1 with antibodies or specific antagonists has been found to have protective effects in established preclinical inflammatory disease models, including models of lethal endotoxemia and sepsis. In the present study, emerging evidence supporting the notion that extracellular HMGB1 acts as a proinflammatory danger signal is reviewed, and the potential therapeutic effects of a wide array of HMGB1 inhibitors agents in sepsis and ischemic injury are discussed.

Safety and tolerability of Panax ginseng root extract: a randomized, placebo-controlled, clinical trial in healthy Korean volunteers

OBJECTIVES

Panax ginseng has been extensively used as an adaptogen and is among the top 10 selling herbal supplements in the United States over the past decade. However, there have been few reports about the toxicity of P. ginseng in human studies. Given the lack of toxicological studies in human, this study investigated whether P. ginseng administration causes any noticeable toxic effects in healthy volunteers.

METHODS

This study was designed as a randomized, double-blind, placebo-controlled, and parallel group trial in healthy volunteers. The subjects were required to be healthy, free from any significant disease, as assessed at screening by physical examination, medical history, and laboratory (hematological and biochemical) tests. Eligible subjects received P. ginseng extract (1 g/day or 2 g/day) or placebo over a 4-week period.

RESULTS

Although mild adverse events, such as dyspepsia, hot flash, insomnia, and constipation, were reported in both P. ginseng and placebo group, no serious untoward reactions were reported following P. ginseng administration. Nonsignificant changes were observed in hematological and biochemical tests.

CONCLUSIONS

P. ginseng administration for 4 weeks was shown to be safe, tolerable, and free of any untoward toxic effect in healthy male and female volunteers. Future results from ongoing multicenter collaborative efforts to evaluate short- and long-term effects of P. ginseng may contribute to our current understanding of safety and tolerability of this herbal product.

Metabolism of ginseng and its interactions with drugs

Ginseng is an herbal medicine used worldwide. It is reported to have a wide range of pharmacological activities because of a diversified group of steroidal saponins called ginsenosides. Compared to extensive pharmacological studies of ginseng, the pharmacokinetics, especially the metabolism of this herb, has received less attention. In this article we review the known pharmacokinetic data on ginseng. Understanding ginseng's pharmacokinetics may reduce the potential for interactions in patients who use both ginseng and prescription medications. In addition, bioavailability after taking ginseng orally is low, and the metabolites of ginsenosides produced by gut microbiota may be biologically active. One ginseng metabolite, Compound K, and its potential for cancer chemoprevention is also discussed. An active ginseng metabolite may differ in distribution and clearance from its parent compound, and the parent compound and its metabolite may be bioactive by similar or different mechanisms. Thus, further investigation of ginseng metabolites is needed for predicting the therapeutic outcome with ginseng.

Inhibitory effects of kaempferol-3-O-sophoroside on HMGB1-mediated proinflammatory responses

High mobility group box 1 (HMGB1) protein is secreted by activated cells of the innate immune system and/or released by injured tissues and necrotic cells; HMGB1 up-regulates proinflammatory cytokines in several inflammatory diseases. Kaempferol-3-O-sophoroside (KP) was isolated from the leaves of cultivated mountain ginseng. KP has antitumor, antioxidative, antiallergic and antidiabetic activities, but the effects of KP on HMGB1-mediated proinflammatory responses have not been studied. In this study, we monitored the effect of KP on the lipopolysaccharide (LPS)-mediated release of HMGB1 and the HMGB1-mediated modulation of proinflammatory responses in human endothelial cells. We found that KP potently inhibited the release of HMGB1 by LPS and inhibited LPS- or HMGB1-mediated barrier permeability and expression of cell adhesion molecules. Further studies revealed that KP inhibited cell surface receptor of HMGB1, toll-like receptor (TLR) 2/4, but not the receptor for advanced glycation end products (RAGE). Collectively, these results suggest that KP possesses anti-inflammatory responses against HMGB1-mediated proinflammatory responses, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases.

Induction of cytochrome P450 3A by Shexiang Baoxin Pill and its main components

The expression of cytochrome P450 is regulated by both endogenous factors and xenobiotics including chemical drugs and natural medicines. Induction on cytochrome P450 can reduce the therapeutic efficacy from drugs inactivated by this enzyme system, but may increase the efficacy or lead to intoxication for prodrugs. Shexiang Baoxin Pill (SBP) is a traditional Chinese medicine widely used for the treatment of angina pectoris and myocardial infarction in China and other oriental countries. To assess the potential of SBP to alter the activity and expression of cytochrome P450 3A (CYP3A) extensively involved in drug metabolism, we investigated the enzyme-inducing effects of SBP in HepG2 cells and in rats. The results showed that treatment with SBP increased the enzyme activity, mRNA levels and protein expression of CYP3A4 in a concentration-dependent manner in HepG2 cells. Moreover, treatment with SBP enhanced the activities and mRNA expressions of CYP3A1 and CYP3A2 ex vivo in rats. Furthermore, we utilized HepG2 cell line to identify individual components in SBP as potential inducers of CYP3A4. It was found that bufalin, cinobufagin, and resibufogenin were novel CYP3A4 inducers. Among them, bufalin and cinobufagin significantly promoted the CYP3A4 enzyme activity, mRNA and protein levels, with the maximal induction challenging or exceeding that of the induction by rifampicin, indicating that they might play a critical role in CYP3A4 enzyme-inducing effects of SBP. In addition, the metabolic studies with specific inhibitors of CYP isoforms suggested that the three CYP3A4 inducers in SBP are also the substrates for the enzyme. Overall, our results show that SBP contains constituents that can potently induce CYP3A and suggest that this traditional Chinese medicine should be examined clinically for potential drug metabolic interactions.

The effect of Compound Danshen Dripping Pills, a Chinese herb medicine, on the pharmacokinetics and pharmacodynamics of warfarin in rats

AIM OF THE STUDY

Significant pharmacokinetic/pharmacodynamic (PK/PD) interactions between various herbal products and warfarin have recently been reported. The present study was conducted to determine whether Compound Danshen Dripping Pills (CDDP), a Chinese herb medicine used for the treatment of cardiovascular diseases, interacts with warfarin when administered concomitantly.

MATERIALS AND METHODS

Each day for 7 days two groups of rats were treated orally with CDDP (50mg/kg and 250 mg/kg, twice daily), and the control group received similar treatment with appropriate volumes of water only. Sixty minutes after the final daily administration of CDDP or water, an aqueous solution of warfarin (0.2mg/mL) was given to each rat at a dose of 1.0mg/kg, and blood samples were collected at 0, 0.5, 1, 2, 4, 8, 12, 24, 36, and 48 h after warfarin-treatment. The concentration of warfarin in blood plasma was determined by high performance liquid chromatography (HPLC). Prothrombin time (PT) in blood plasma was measured using thromboplastin reagent.

RESULTS

Excellent linearity was found between 0.05 and 10 μg/mL with a lower limit of quantitation (LLOQ) of 0.05 ng/mL (r>0.999); moreover, all the validation data including accuracy and precision (intra- and inter-day), were within the required limits. No significant differences were found in PT(max) and AUC(PT0-∞) between the two CDDP-treated groups and the control. Besides, there was little alteration in any of the pharmacokinetic parameters of warfarin between the two CDDP-treated groups and the control.

CONCLUSION

The concomitant application of CDDP and warfarin did not give rise to significant effect on the pharmacodynamics of warfarin, and practically no effect on its pharmacokinetics. It was speculated that the PK/PD interactions between CDDP and warfarin was likely to be negligible as long as the patients took CDDP at a normal dose.

Novel dammarane-type sapogenins from Panax ginseng berry and their biological activities

Three new dammarane-type sapogenins (1, 3, and 5) together with two known ones (2 and 4) were isolated from the total hydrolyzed saponins extracted from Panax ginseng berry. Their structures were elucidated using a combination of 1D and 2D (1)H and (13)C NMR spectra and mass spectroscopy as 20(R)-25-methoxyl-dammarane-3β,12β,20-triol (1), 20(R)-25-methoxyl-dammarane-3β,6α,12β,20-tetrol (2), 20(R)-20-methoxyl-dammarane-3β,12β,25-triol (3), 20(R)-20,25-dimethoxyl-dammarane-3β,12β-diol (4), and (12R,20S,24S)-20,24-; 12,24-diepoxy-dammarane-3β-ol (5). Their antitumor activities were evaluated in six human cancer cell lines. The novel compounds 1 and 3 showed significant cytotoxic activity against the six cell lines. The IC(50) values of 3 against HepG2, Colon205, and HL-60 were the lowest (8.78, 8.64, and 3.98 μM, respectively). Compounds 1 and 20(S)-25-OCH(3)-PPD, which are a pair of configuration isomers, showed a 10- to 100-fold greater growth inhibition than ginsenoside-Rg(3) (an anti-cancer clinical agent in China). The data presented here may be useful for the development of novel anti-cancer agents.

Interaction between warfarin and the herbal product Shengmai-yin: a case report of intracerebral hematoma

A 71-year-old man was stable on warfarin (2.25 mg daily) therapy with an international normalized ratio (INR) of 1.8-2.2 after a heart valve replacement surgery. Recently, he consumed the liquid-like herbal product called shengmai-yin (10 mL daily) against medical advice. Seven days after the daily consumption of shengmai-yin, he was admitted to the intensive care unit because of consciousness disturbance [Glasgow Coma Scale (GCS) score 7] with an INR of 5.08. Head computed topography revealed intracerebral hematoma in the left temporoparietal region. Both warfarin therapy and the herbal product were withdrawn. At the same time, therapy with intravenous vitamin K1 40 mg was started. On the second day of admission, craniectomy was performed to remove the intacerebral hematoma under general anesthesia. He remained confused and restless for 2 days, but then showed progressive recovery in the consciousness level as well as motor and verbal functions. Shengmai-yin contains herbal ingredients that can interact with warfarin. The Drug Interaction Probability Scale (DIPS) indicated that warfarin and shengmai-yin were highly probable causes of intracerebral hematoma. Patients on warfarin therapy should be discouraged from taking herbal medicines, especially preparations that are already known to have antiplatelet and antithrombotic effects.

Study on the pharmacokinetics drug-drug interaction potential of Glycyrrhiza uralensis, a traditional Chinese medicine, with lidocaine in rats

Drug-drug interaction potentials of an herbal medicine named Glycyrrhiza uralensis was investigated in rats via in vitro and in vivo pharmacokinetic studies. P(450) levels and the metabolic rate of lidocaine in the liver microsomes prepared from different treatment groups were measured. In a separate in vivo pharmacokinetic study, the pharmacokinetic parameters of lidocaine in plasma and urine were estimated. P(450) levels in the rats pretreated by Glycyrrhiza uralensis were significant higher than that in the non-treatment control. The increase in P(450) levels was dose-dependent. Glycyrrhiza uralensis (1 and 3 g/kg) increased P(450) levels by 62% and 91%, respectively, compared with the non-treatment control (0.695 nmol/mg protein). The metabolic rate of lidocaine in the liver microsomes was significantly higher in the herb pretreated rats. The pharmacokinetic profile of lidocaine was significantly modified in the rats with the herbal pretreatment. Elimination half-lives were shortened by 39%, and total clearances were increased by 59% with the pretreatment of Glycyrrhiza uralensis. In conclusion, Glycyrrhiza uralensis showed induction effect on P(450) isozymes. Efficacy and safety profiles of a drug may be affected when the herbal products or herbal prescriptions containing the plant medicine were concomitantly used.

Pharmacokinetic and pharmacodynamic study of interaction of Rhodiola rosea SHR-5 extract with warfarin and theophylline in rats

Significant pharmacokinetic/pharmacodynamic interactions between various herbal products and drugs being substrates of cytochrome P450 have recently been reported. The aim of this study was to determine whether Rhodiola rosea SHR-5 extract interacts with warfarin and theophylline when administered concomitantly. Thus, concomitant treatment of rats with theophylline and SHR-5 did not give rise to significant effects on the pharmacokinetics of theophylline. Simultaneous administration of SHR-5 and warfarin did not alter significantly the pharmacokinetics or the anticoagulant activity of warfarin. It is concluded that SHR-5 might be of value in the treatment of patients with mild or moderate depression, and that its interaction with co-administered drugs is likely to be negligible.

Interaction between warfarin and Panax ginseng in ischemic stroke patients

BACKGROUND

Today, the combined use of Oriental herbal medicines and Western biomedical medicines has been a prevalent yet controversial practice. Case reports and healthy volunteer trials have had conflicting results on the effect Panax ginseng has on warfarin's pharmacologic action, some reporting a reductive and others a potentiating influence.

OBJECTIVE

This study investigated the interaction between warfarin and P. ginseng by observing the prothrombin time (PT) and the international normalized ratio (INR) in ischemic stroke patients who did not have a history of taking warfarin.

DESIGN

Randomized, open-label, controlled study.

SUBJECTS

Twenty-five (25) patients newly diagnosed with ischemic stroke by brain computed tomography or magnetic resonance imaging in the Korean Medical Hospital, Kyung Hee University (Seoul, Republic of Korea).

INTERVENTION

Ischemic stroke patients were randomized into 2 groups: the ginseng group (n = 12), given both P. ginseng and warfarin, and the control group (n = 13), given only warfarin, both for 2 weeks. The warfarin dose was restricted to 2 mg in the first week and 5 mg in the second week.

RESULTS

The peak values and the international normalized ratio (INR) and prothrombin time (PT) areas under the curve (AUC) in both groups significantly increased compared to those at baseline. However, there was no statistically significant difference in peak values and INR and PT AUC between groups in both the first and second weeks.

CONCLUSIONS

This study suggests that coadministration of P. ginseng and warfarin in ischemic stroke patients does not influence the pharmacologic action of warfarin.

Herbal remedies for menopausal symptoms: are we cautious enough?

OBJECTIVES

To evaluate adverse effects of herbal remedies consumed by menopausal women for control of the climacteric syndrome.

METHODS

We examined the long term safety and herb-drug interactions of commonly used herbal therapy such as soy, black cohosh, dong quai, ginseng and vitamin E.

RESULTS

Even carefully designed studies on herbal treatments for vasomotor menopausal symptoms never addressed specifically safety issues. Sporadic reports show dangerous adverse effects of these herbal preparations as well as hazardous interactions between botanic compounds and conventional medications.

CONCLUSIONS

The unrestricted sale of plant products constitutes a new situation for physicians with little training in phytotherapy. The qualitative and quantitative diversity of the commercially available preparations, the absence of precise prescribing guidelines, and the risk of self-prescribed medication justify the introduction of 'phyto-vigilance'. Physicians should warn their patients about the lack of evidence regarding safety and possible interactions of herbal remedies with concurrent medications.

Consumption of herbal remedies and dietary supplements amongst patients hospitalized in medical wards

AIMS

Herbal remedies may have adverse effects and potentially serious interactions with some commonly prescribed conventional medications. Little is known about consumption of herbal remedies and dietary supplements by hospitalized patients. The aim was to evaluate the rate of consumption and characterize the patients hospitalized in internal medicine departments who consume herbal remedies and dietary supplements. Also, to assess the medical teams' awareness and assess the percentage of patients with possible drug-herb interactions.

METHODS

Patients hospitalized in the medical wards of two hospitals in Israel were interviewed about their use of herbal remedies or dietary supplements. The medical records were searched for evidence that the medical team had knowledge of the use of herbal remedies or dietary supplements.

RESULTS

Two hundred and ninety-nine hospitalized medical patients were interviewed. Of the participants, 26.8% were herbal or dietary supplement consumers (HC). On multivariate analysis the only variates associated with herbal or dietary supplement consumption were the hospital [odds ratio (OR) 2.97, 95% confidence interval (CI) 1.29, 6.52], income (OR 0.39, 95% CI 0.15, 1.05), smoking habits (OR 0.17, 95% CI 0.05, 0.55) and benign prostatic hypertrophy (OR 4.64, 95% CI 1.3, 16.5). Ninety-four percent of the patients had not been asked specifically of herbal consumption by the medical team. Only 23% of the hospital's medical files of the HC patients had any record of the use of herbal or dietary supplements. Seven possible drug-herbal interactions were encountered (7.1%). The most serious was an interaction between camomile tea and ciclosporin.

CONCLUSIONS

Herbal remedy consumption is common amongst patients hospitalized in internal medicine wards and is often overlooked by the medical team. Patients and doctors should be more aware of the possible adverse effects and of the potential of herb-drug interactions.

Potential drug–herb interaction with antiplatelet/anticoagulant drugs

This is a cross-sectional survey evaluating the use of herbal medicines in medical wards patients that may interfere with the effect of antiplatelet or anticoagulant therapy. Among the 250 patients participated, 42.4% (n=106) were taking herbs with 76 patients (71.7%) using herbs for the past 12 months. Overall, almost 31% (n=23, N=76) of patients were taking one or more of the specified herbal medicines [ginseng (Panax ginseng), garlic (Allium sativum), ginkgo (Gingko biloba) thought to interact with antiplatelet or anticoagulant therapy. The study showed that 21% (n=16, N=76) of patients co-ingested specified herbs with antiplatelet or anticoagulant therapy, of which half of them were at risk of potential drug-herb interactions. A large proportion of respondents involved in potential drug-herb interaction were elderly people (62.5%, n=5). However, more than 90% of herbal users did not disclose the use of herbal medicine to their health professionals. It is thus prudent for all care givers to be aware of the possibility of drug-herb interaction and inquire about herbal use from patients.

Possible drug-metabolism interactions of medicinal herbs with antiretroviral agents

Herbal medicines are widely used by HIV patients. Several herbal medicines have been shown to interact with antiretroviral drugs, which might lead to drug failure. We have aimed to provide an overview of the modulating effects of Western and African herbal medicines on antiretroviral drug-metabolizing and transporting enzymes, focusing on potential herb-antiretroviral drug interactions. Echinacea, garlic, ginkgo, milk thistle, and St. John's wort have the potential to cause significant interactions. In vitro and in vivo animal studies also indicated other herbs with a potential for interactions; however, most evidence is based on in vitro studies. Further pharmacokinetic studies to unveil potential Western and especially African herb-antiretroviral drug interactions are urgently required, and the clinical significance of these interactions should be assessed.

The effect of Kan Jang extract on the pharmacokinetics and pharmacodynamics of warfarin in rats

Significant pharmacokinetic/pharmacodynamic interactions between various herbal products and warfarin have recently been reported. The aim of this study was to determine whether concomitant treatment of rats with Kan Jang (a standardized fixed combination of extracts from Andrographis paniculata and Eleutherococcus senticosus) and warfarin would lead to an alteration in the pharmacological effects of warfarin. Each day for 5 days a group of animals was treated orally with an aqueous solution of Kan Jang at a dose of 17 mg/kg of the active principle andrographolide (a daily dose some 17-fold higher than that recommended for humans): the control group received similar treatment with appropriate volumes of water only. Sixty minutes after the final daily administration of Kan Jang or water, an aqueous solution of warfarin (0.2 mg/ml) was given to each animal at a dose of 2 mg/kg. From each group, 6 animals were sacrificed at 0, 2, 4, 6, 8, 12, 24, 30 and 48 h after warfarin administration and blood samples taken. The concentration of warfarin in blood plasma was measured by capillary electrophoresis using 50 mM borate buffer (pH 9.3) as mobile phase with simultaneous detection of warfarin at 208.1 and 307.5 nm. Prothrombin time in blood plasma was measured using thromboplastin reagent. The concomitant application of Kan Jang and warfarin did not produce significant effects on the pharmacokinetics of warfarin, and practically no effect on its pharmacodynamics.

Dietary supplements: altered coagulation and effects on bruising

BACKGROUND

Patient use of dietary supplements that alter coagulation or have an effect on bruising is becoming increasingly common.

OBJECTIVE

To identify and describe dietary supplements that alter coagulation or are reported to alter bruising during and after surgical procedures.

METHODS

The MEDLINE, Cochrane Collaboration, and International Bibliographic Information on Dietary Supplements databases were searched for articles using the search words "bruising," "bleeding," "coagulation," "hemostasis," "herbal medicine," "alternative medicine," and "dietary supplement." Additional sources were obtained from manual searches of recent journal articles.

RESULTS

In vivo and in vitro evidence supports the notion that many dietary supplements alter coagulation. Limited evidence is available to support anecdotal claims of diminished postoperative bruising after the use of dietary supplements.

CONCLUSION

Surgeons should be aware that many of their patients are taking dietary supplements that may alter coagulation. Because most patients will not readily volunteer this information, specific steps should be taken to obtain it prior to more extensive surgical procedures.

Gender differences in pharmacokinetics of oral warfarin in rats

Gender different pharmacokinetics of warfarin were investigated after oral administration at a dose of 2 mg/kg to male and female rats. The concentrations of warfarin in rat plasma were analysed by the HPLC method. Noncompartmental analysis was used for the calculation of the total area under the plasma concentration-time curve from time zero to time infinity (AUC) and terminal half-life of warfarin. After oral administration of warfarin to female rats, the AUC was significantly greater (345 compared with 180 microg h/ml) than that in male rats.

Cardiovascular pharmacotherapy and herbal medicines: the risk of drug interaction

Use of herbal medicines among patients under cardiovascular pharmacotherapy is widespread. In this paper, we have reviewed the literature to determine the possible interactions between herbal medicines and cardiovascular drugs. The Medline database was searched for clinical articles published between January 1996 and February 2003. Forty-three case reports and eight clinical trials were identified. Warfarin was the most common cardiovascular drug involved. It was found to interact with boldo, curbicin, fenugreek, garlic, danshen, devil's claw, don quai, ginkgo, papaya, lycium, mango, PC-SPES (resulting in over-anticoagulation) and with ginseng, green tea, soy and St. John's wort (causing decreased anticoagulant effect). Gum guar, St. John's wort, Siberian ginseng and wheat bran were found to decrease plasma digoxin concentration; aspirin interactions include spontaneous hyphema when associated with ginkgo and increased bioavailability if combined with tamarind. Decreased plasma concentration of simvastatin or lovastatin was observed after co-administration with St. John's wort and wheat bran, respectively. Other adverse events include hypertension after co-administration of ginkgo and a diuretic thiazide, hypokalemia after liquorice and antihypertensives and anticoagulation after phenprocoumon and St. John's wort. Interaction between herbal medicine and cardiovascular drugs is a potentially important safety issue. Patients taking anticoagulants are at the highest risk.

Effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects

M: The aim of this study was to investigate the effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin.

METHODS

This was an open-label, three-way crossover randomized study in 12 healthy male subjects, who received a single 25-mg dose of warfarin alone or after 14 days' pretreatment with St John's wort, or 7 days' pretreatment with ginseng. Dosing with St John's wort or ginseng was continued for 7 days after administration of the warfarin dose. Platelet aggregation, international normalized ratio (INR) of prothrombin time, warfarin enantiomer protein binding, warfarin enantiomer concentrations in plasma and S-7-hydroxywarfarin concentration in urine were measured. Statistical comparisons were made using anova and 90% confidence intervals are reported.

RESULTS

INR and platelet aggregation were not affected by treatment with St John's wort or ginseng. The apparent clearances of S-warfarin after warfarin alone or with St John's wort or ginseng were, respectively, 198 +/- 38 ml h(-1), 270 +/- 44 ml h(-1) and 220 +/- 29 ml h(-1). The respective apparent clearances of R-warfarin were 110 +/- 25 ml h(-1), 142 +/- 29 ml h(-1) and 119 +/- 20 ml h(-1) [corrected]. The mean ratio and 90% confidence interval (CI) of apparent clearance for S-warfarin was 1.29 (1.16, 1.46) and for R-warfarin it was 1.23 (1.11, 1.37) when St John's wort was coadministered. The mean ratio and 90% CI of AUC(0-168) of INR was 0.79 (0.70, 0.95) when St John's wort was coadministered. St John's wort and ginseng did not affect the apparent volumes of distribution or protein binding of warfarin enantiomers.

CONCLUSIONS

St John's wort significantly induced the apparent clearance of both S-warfarin and R-warfarin, which in turn resulted in a significant reduction in the pharmacological effect of rac-warfarin. Coadministration of warfarin with ginseng did not affect the pharmacokinetics or pharmacodynamics of either S-warfarin or R-warfarin.

Herbal remedies in the United States: potential adverse interactions with anticancer agents

PURPOSE

Interest in the use of herbal products has grown dramatically in the Western world. Recent estimates suggest an overall prevalence for herbal preparation use of 13% to 63% among cancer patients. With the narrow therapeutic range associated with most anticancer drugs, there is an increasing need for understanding possible adverse drug interactions in medical oncology.

METHODS

In this article, a literature overview is provided of known or suspected interactions of the 15 best-selling herbs in the United States with conventional allopathic therapies for cancer.

RESULTS

Herbs with the potential to significantly modulate the activity of drug-metabolizing enzymes (notably cytochrome p450 isozymes) and/or the drug transporter P-glycoprotein include garlic (Allium sativum), ginkgo (Ginkgo biloba), echinacea (Echinacea purpurea), ginseng (Panax ginseng), St John' s wort (Hypericum perforatum), and kava (Piper methysticum). All of these products participate in potential pharmacokinetic interactions with anticancer drugs.

CONCLUSION

It is suggested that health care professionals and consumers should be aware of the potential for adverse interactions with these herbs, question their patients on their use of them, especially among patients whose disease is not responding to treatments as expected, and urge patients to avoid herbs that could confound their cancer care.

Toxicological aspects of Kampo medicines in clinical use

Among 210 medicinal prescriptions used in present-day Japan, the clinical uses and the acute, chronic and mutagenic toxicity study of 16 Kampo (Japanese herbal) medicines are summarized. These Kampo medicines are classified into two categories; eight prescriptions containing Bupleurum root (Bupleurum falcatum L.) such as Sho-saiko-to and Saiko-keishi-to, and eight prescriptions not containing Bupleurum root such as Juzen-taiho-to and Ninjin-yoei-to. Studies of some potential interaction between herbal medicine and western drugs are also described.

Interactions of herbs with cytochrome P450

A resurgence in the use of medical herbs in the Western world, and the co-use of modern and traditional therapies is becoming more common. Thus there is the potential for both pharmacokinetic and pharmacodynamic herb-drug interactions. For example, systems such as the cytochrome P450 (CYP) may be particularly vulnerable to modulation by the multiple active constituents of herbs, as it is well known that the CYPs are subject to induction and inhibition by exposure to a wide variety of xenobiotics. Using in vitro, in silico, and in vivo approaches, many herbs and natural compounds isolated from herbs have been identified as substrates, inhibitors, and/or inducers of various CYP enzymes. For example, St. John's wort is a potent inducer of CYP3A4, which is mediated by activating the orphan pregnane X receptor. It also contains ingredients that inhibit CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Many other common medicinal herbs also exhibited inducing or inhibiting effects on the CYP system, with the latter being competitive, noncompetitive, or mechanism-based. It appears that the regulation of CYPs by herbal products complex, depending on the herb type, their administration dose and route, the target organ and species. Due to the difficulties in identifying the active constituents responsible for the modulation of CYP enzymes, prediction of herb-drug metabolic interactions is difficult. However, herb-CYP interactions may have important clinical and toxicological consequences. For example, induction of CYP3A4 by St. John's wort may partly provide an explanation for the enhanced plasma clearance of a number of drugs, such as cyclosporine and innadivir, which are known substrates of CYP3A4, although other mechanisms including modulation of gastric absorption and drug transporters cannot be ruled out. In contrast, many organosulfur compounds, such as diallyl sulfide from garlic, are potent inhibitors of CYP2E1; this may provide an explanation for garlic's chemoproventive effects, as many mutagens require activation by CYP2E1. Therefore, known or potential herb-CYP interactions exist, and further studies on their clinical and toxicological roles are warranted. Given that increasing numbers of people are exposed to a number of herbal preparations that contain many constituents with potential of CYP modulation, high-throughput screening assays should be developed to explore herb-CYP interactions.

Reversal of P-glycoprotein-mediated multidrug resistance by ginsenoside Rg(3)

Multidrug resistance has been a major problem in cancer chemotherapy. In this study, in vitro and in vivo modulations of MDR by ginsenoside Rg(3), a red ginseng saponin, were investigated. In flow cytometric analysis using rhodamine 123 as an artificial substrate, Rg(3) promoted accumulation of rhodamine 123 in drug-resistant KBV20C cells in a dose-dependent manner, but it had no effect on parental KB cells. Additionally Rg(3) inhibited [3H]vinblastine efflux and reversed MDR to doxorubicin, COL, VCR, and VP-16 in KBV20C cells. Reverse transcriptase-polymerase chain reaction and immuno-blot analysis after exposure of KBV20C cells to Rg(3) showed that inhibition of drug efflux by Rg(3) was due to neither repression of MDR1 gene expression nor Pgp level. Photo-affinity labeling study with [3H]azidopine, however, revealed that Rg(3) competed with [3H]azidopine for binding to the Pgp demonstrating that Rg(3) competed with anticancer drug for binding to Pgp thereby blocking drug efflux. Furthermore, Rg(3) increased life span in mice implanted with DOX-resistant murine leukemia P388 cells in vivo and inhibited body weight increase significantly.

Panax ginseng: a systematic review of adverse effects and drug interactions

Panax ginseng C. A. Meyer is a perennial herb native to Korea and China and has been used as an herbal remedy in eastern Asia for thousands of years. Modern therapeutic claims refer to vitality, immune function, cancer, cardiovascular diseases, improvement of cognitive and physical performance and sexual function. A recent systematic review of randomised controlled trials found that the efficacy of ginseng root extract could not be established beyond doubt for any of these indications. In order to obtain a balanced assessment of the therapeutic value of P. ginseng it is also necessary to consider the safety profile. In view of the extremely widespread use of P. ginseng it seems important to ask whether this herbal medicine involves health risks for the consumer. This review was conducted as a systematic attempt to document and evaluate all the available safety data on P. ginseng root extracts. Systematic searches were performed in five electronic databases and the reference lists of all papers located were checked for further relevant publications. All articles containing original data on adverse events and drug interactions with P. ginseng were included. Information was also requested from 12 manufacturers of ginseng preparations, the spontaneous reporting schemes of the WHO and national drug safety bodies. No language restrictions were imposed. Data from clinical trials suggest that the incidence of adverse events with ginseng monopreparations is similar to that with placebo. The most commonly experienced adverse events are headache, sleep and gastrointestinal disorders. The possibility of more serious adverse events is indicated in isolated case reports and data from spontaneous reporting schemes; however, causality is often difficult to determine from the evidence provided. Combination products containing ginseng as one of several constituents have been associated with serious adverse events and even fatalities. Interpretation of these cases is difficult as ingredients other than P. ginseng may have caused the problems. Possible drug interactions have been reported between P. ginseng and warfarin, phenelzine and alcohol. Collectively, these data suggest that P. ginseng monopreparations are rarely associated with adverse events or drug interactions. The ones that are documented are usually mild and transient. Combined preparations are more often associated with such events but causal attribution is usually not possible.

Herbal interactions with cardiovascular drugs

The prevalence of herb-drug interactions has been exaggerated. Nonetheless, some herbs, including garlic, ginkgo, ginseng, and St John's wort, can have a significant influence on concurrently administered drugs. Herbal medicines may mimic, decrease, or increase the action of prescribed drugs. This can be especially important for drugs with narrow therapeutic windows and in sensitive patient populations such as older adults, the chronically ill, and those with compromised immune systems.

Hematologic complications of alternative remedies

The use of alternative therapies increased dramatically over the last decade with a wide variety of methods and interventions. Dietary supplements are a very common form of alternative therapy used by healthy people as well as patients with serious health problems. The use of these untested, unregulated therapies may carry inherent risks. Hematologic complications are known side effects of these remedies and may present potentially life-threatening events. This manuscript discusses the clinical manifestations and mechanisms of action of these remedies and provides recommendations for patients' evaluation and counseling.

Are emergency department patients at risk for herb-drug interactions?

OBJECTIVES

To determine the prevalence of herbal and/or dietary supplement use and identify patients at risk for herb-drug interactions.

METHODS

A convenience sample of 944 patients were surveyed to determine the prevalence and types of supplements used. Patients with heart disease, diabetes, psychiatric disorders, and/or hypertension were assessed for potential interactions.

RESULTS

One hundred thirty-five (14.3%) patients reported regular use. Of these, 79.3% were taking supplements concurrently with prescription medications, and 80.0% were administered medication(s) in the emergency department. Cardiac: 19.8% (n = 33) reported regular use, with four potential interactions. Hypertension: 20.3% (n = 54) reported regular use, with two potential interactions. Diabetes: 15.9% (n = 20) reported regular use, with no known interactions. Psychiatric: 15.9% (n = 10) reported regular use, with one potential interaction.

CONCLUSIONS

Six patients were identified at risk for seven known herb-drug interactions. The prevalence of undisclosed herbal supplement use and lack of research on these supplements suggest that more patients may be at risk.