[Kava-induced acute icteric hepatitis]

Recreational Drugs and the Risk of Hepatocellular Carcinoma

Recreational or aesthetic drug use is a distinctive behavior of humans, principally attested in the last century. It is known that recreational and illegal drugs are major contributors to the universal morbidity rate worldwide. Many of these substances have a well-established hepatotoxic potential, causing acute or chronic liver injury, liver fibrosis and cirrhosis, but their implications for hepatocellular carcinoma or other varieties of liver tumors are little known. In this article, we perform an extensive literature review, aiming to provide updated information about recreational drug use and the risk of developing liver tumors. Khat use and pyrrolizidine alkaloid consumption (present in some natural plants) have been linked to liver cirrhosis. Kava intake is associated with different liver tumors in animal models but not in humans. Cannabis' potential to accelerate liver fibrosis in chronic hepatitis is controversial according to the existing data. Cigarette smoking is an important contributor to hepatocellular carcinoma, and anabolic androgen steroids are well-defined causes of a variety of liver cancers and other hepatic tumors. Long-term follow-up studies of subjects who have developed injuries in association with the use of recreational drugs are warranted so as to better define the risk of developing hepatocellular carcinoma in association with these substances and, thus, to implement health care policies to combat this preventable cause of cancer.

Liver toxicity related to herbs and dietary supplements: Online table of case reports. Part 2 of 5 series

BACKGROUND

No online current list of potentially life-threatening, hepatotoxic herbs and dietary supplements based on PubMed case reports exists in a summarized tabular form.

METHODS

Documented case reports of herbs or dietary supplements (DS; includes herbs) appearing to contribute to liver injury were used to create an online "DS Toxic Table" of potentially hepatotoxic herbs and dietary supplements (PubMed, 1966 to June, 2016, and cross-referencing). The spectrum of DS induced liver injuries (DSILI) included elevated liver enzymes, hepatitis, steatosis, cholestasis, hepatic necrosis, hepatic fibrosis, hepatic cirrhosis, veno-occlusive disease, acute liver failure requiring a liver transplant, and death.

RESULTS

Over the past 50 years, approximately 21 herbs (minus germander and usnic acid that are no longer sold) and 12 dietary supplements (minus the nine no longer sold and vitamin A & niacin due to excess intake) posed a possible risk for liver injures in certain individuals. The herbs with the most number of reported publications (but not cases studies) in descending order, were germander, black cohosh, kava extract, and green tea extract.

CONCLUSION

These online DS Toxic Tables will contribute to continued Phase IV post marketing surveillance to detect possible liver toxicity cases and serve to forewarn consumers, clinicians, and corporations.

Herbal Hepatotoxicity: Clinical Characteristics and Listing Compilation

Herb induced liver injury (HILI) and drug induced liver injury (DILI) share the common characteristic of chemical compounds as their causative agents, which were either produced by the plant or synthetic processes. Both, natural and synthetic chemicals are foreign products to the body and need metabolic degradation to be eliminated. During this process, hepatotoxic metabolites may be generated causing liver injury in susceptible patients. There is uncertainty, whether risk factors such as high lipophilicity or high daily and cumulative doses play a pathogenetic role for HILI, as these are under discussion for DILI. It is also often unclear, whether a HILI case has an idiosyncratic or an intrinsic background. Treatment with herbs of Western medicine or traditional Chinese medicine (TCM) rarely causes elevated liver tests (LT). However, HILI can develop to acute liver failure requiring liver transplantation in single cases. HILI is a diagnosis of exclusion, because clinical features of HILI are not specific as they are also found in many other liver diseases unrelated to herbal use. In strikingly increased liver tests signifying severe liver injury, herbal use has to be stopped. To establish HILI as the cause of liver damage, RUCAM (Roussel Uclaf Causality Assessment Method) is a useful tool. Diagnostic problems may emerge when alternative causes were not carefully excluded and the correct therapy is withheld. Future strategies should focus on RUCAM based causality assessment in suspected HILI cases and more regulatory efforts to provide all herbal medicines and herbal dietary supplements used as medicine with strict regulatory surveillance, considering them as herbal drugs and ascertaining an appropriate risk benefit balance.

Herbal hepatotoxicity in traditional and modern medicine: actual key issues and new encouraging steps

Plants are natural producers of chemical substances, providing potential treatment of human ailments since ancient times. Some herbal chemicals in medicinal plants of traditional and modern medicine carry the risk of herb induced liver injury (HILI) with a severe or potentially lethal clinical course, and the requirement of a liver transplant. Discontinuation of herbal use is mandatory in time when HILI is first suspected as diagnosis. Although, herbal hepatotoxicity is of utmost clinical and regulatory importance, lack of a stringent causality assessment remains a major issue for patients with suspected HILI, while this problem is best overcome by the use of the hepatotoxicity specific CIOMS (Council for International Organizations of Medical Sciences) scale and the evaluation of unintentional reexposure test results. Sixty five different commonly used herbs, herbal drugs, and herbal supplements and 111 different herbs or herbal mixtures of the traditional Chinese medicine (TCM) are reported causative for liver disease, with levels of causality proof that appear rarely conclusive. Encouraging steps in the field of herbal hepatotoxicity focus on introducing analytical methods that identify cases of intrinsic hepatotoxicity caused by pyrrolizidine alkaloids, and on omics technologies, including genomics, proteomics, metabolomics, and assessing circulating micro-RNA in the serum of some patients with intrinsic hepatotoxicity. It remains to be established whether these new technologies can identify idiosyncratic HILI cases. To enhance its globalization, herbal medicine should universally be marketed as herbal drugs under strict regulatory surveillance in analogy to regulatory approved chemical drugs, proving a positive risk/benefit profile by enforcing evidence based clinical trials and excellent herbal drug quality.

Characterizing the human equivalent dose of herbal medicines in animal toxicity studies

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicines have been generally believed to be safe. With the increasing use of herbal medicine worldwide, however, the safety of traditional herbal drugs frequently becomes a medical issue.

AIM OF THE STUDY

This study was aimed to characterize the safe dose of herbal medicines through the systematic review for "human equivalent dose (HED)" from animal-based toxicity studies.

METHODS AND MATERIALS

A literature search for animal-based toxicity studies of herbal medicines in eight databases, including PubMed and Embase, was performed without language restriction. From the "no observed adverse effect level (NOAEL)" of each animal study, HED values were then calculated according to the composition (single or multiple herbs) and indication of the medicines.

RESULTS

Among 729 relevant articles identified in the initial screening, 112 (233 studies comprising 105 single-herb and 128 multiple-herb studies) that met our inclusion criteria were finally reviewed. The total average HED value (from mouse, rat, rabbit and dog) was 278.1±358.0 mg/kg, and the values for single- and multiple-herb studies were 322.7±488.4 mg/kg and 241.5±189.2 mg/kg, respectively. When the studies were analyzed according to herbal drug indication, drugs used for revitalization had the highest HED value (433.0±265.2 mg/kg), while those for infectious diseases had the lowest (110.6±118.6 mg/kg).

CONCLUSIONS

Our results provide important information regarding the safe dose of herbal medicines; thus, these data offer researchers and practitioners information critical for drug development or clinical application.

Herbs and liver injury: a clinical perspective

Despite a perception that herbal and dietary supplements are safe, devastating liver injury has been reported to result from their use. The difficulty in characterizing liver injury attributable to herbal and dietary supplements stems from the permissive regulatory environment, the complexity of marketed products, and underreporting by the patients who use them. Despite these limitations, researchers, clinicians, and regulators have increasing awareness of the need for study in this area.

Herbal hepatotoxicity: a tabular compilation of reported cases

BACKGROUND

Herbal hepatotoxicity is a field that has rapidly grown over the last few years along with increased use of herbal products worldwide.

AIMS

To summarize the various facets of this disease, we undertook a literature search for herbs, herbal drugs and herbal supplements with reported cases of herbal hepatotoxicity.

METHODS

A selective literature search was performed to identify published case reports, spontaneous case reports, case series and review articles regarding herbal hepatotoxicity.

RESULTS

A total of 185 publications were identified and the results compiled. They show 60 different herbs, herbal drugs and herbal supplements with reported potential hepatotoxicity, additional information including synonyms of individual herbs, botanical names and cross references are provided. If known, details are presented for specific ingredients and chemicals in herbal products, and for references with authors that can be matched to each herbal product and to its effect on the liver. Based on stringent causality assessment methods and/or positive re-exposure tests, causality was highly probable or probable for Ayurvedic herbs, Chaparral, Chinese herbal mixture, Germander, Greater Celandine, green tea, few Herbalife products, Jin Bu Huan, Kava, Ma Huang, Mistletoe, Senna, Syo Saiko To and Venencapsan(®). In many other publications, however, causality was not properly evaluated by a liver-specific and for hepatotoxicity-validated causality assessment method such as the scale of CIOMS (Council for International Organizations of Medical Sciences).

CONCLUSIONS

This compilation presents details of herbal hepatotoxicity, assisting thereby clinical assessment of involved physicians in the future.

Herbal remedies, mood, and cognition

Herbal medicines were the "sole" source of medicine for thousands of years, in every culture since the advent of human civilization. Today, patients are increasing the use of these botanicals for numerous conditions, such as mood and cognition. This article will explore commonly used herbal remedies for mood and cognition functioning. It is imperative that nurses and nurse practitioners obtain expertise with these botanicals with regard to efficacy, adverse effects and contraindications, possible drug interactions, and safety considerations.

Liver toxicity and carcinogenicity in F344/N rats and B6C3F1 mice exposed to Kava Kava

Kava Kava is an herbal supplement used as an alternative to antianxiety drugs. Although some reports suggest an association of Kava Kava with hepatotoxicity , it continues to be used in the United States due to lack of toxicity characterization. In these studies F344/N rats and B6C3F1 mice were administered Kava Kava extract orally by gavage in corn oil for two weeks, thirteen weeks or two years. Results from prechronic studies administered Kava Kava at 0.125 to 2g/kg body weight revealed dose-related increases in liver weights and incidences of hepatocellular hypertrophy. In the chronic studies, there were dose-related increases in the incidences of hepatocellular hypertrophy in rats and mice administered Kava Kava for up to 1g/kg body weight. This was accompanied by significant increases in incidences of centrilobular fatty change. There was no treatment- related increase in carcinogenic activity in the livers of male or female rats in the chronic studies. Male mice showed a significant dose-related increase in the incidence of hepatoblastomas. In female mice, there was a significant increase in the combined incidence of hepatocellular adenoma and carcinoma in the low and mid dose groups but not in the high dose group. These findings were accompanied by several nonneoplastic hepatic lesions.

Kava hepatotoxicity: pathogenetic aspects and prospective considerations

Kava hepatotoxicity is a well-defined herb-induced liver injury, caused by the use of commercial anxyolytic ethanolic and acetonic kava extracts, and of traditional recreational aqueous kava extracts. The aim of this review is to elucidate possible pathogenetic factors for the development of kava-induced liver injury, considering also confounding variables. In patients with liver disease in a causal relation to kava ± comedication, confounding factors include non-adherence to therapy recommendations and comedication consisting of synthetic and herbal drugs and dietary supplements including herbal ones and herbs-kava mixtures. Various possible pathogenetic factors have to be discussed and comprise metabolic interactions with exogenous compounds at the hepatic microsomal cytochrome P450 level; genetic enzyme deficiencies; toxic constituents and metabolites derived from the kava extract including impurities and adulterations; cyclooxygenase inhibition; P-glycoprotein alterations; hepatic glutathione depletion; solvents and solubilizers of the extracts; and kava raw material of poor quality. In particular, inappropriate kava plant parts and unsuitable kava cultivars may have been used sometimes for manufacturing the kava extracts instead of the rhizome of a noble cultivar of the kava plant (Piper methysticum G. Forster). In conclusion, kava hepatotoxicity occurred independently of the extraction medium used for the kava extracts and may primarily be attributed to daily overdose, prolonged treatment and to a few kava extract batches of poor quality; by improving kava quality and adherence to therapy recommendation under avoidance of comedication, liver injury by kava should be a preventable disease, at least to a major extent.

Gene expression profiling as an initial approach for mechanistic studies of toxicity and tumorigenicity of herbal plants and herbal dietary supplements

Dietary supplements are consumed by more than 300 million people worldwide, and herbal dietary supplements represent the most rapidly growing portion of this industry. Even though adverse health effects of many herbal dietary supplements have been reported, safety assurances are not being addressed adequately. Toxicological data on the identification of genotoxic and tumorigenic ingredients in many raw herbs are also lacking. Currently, more than 30 herbal dietary supplements and active ingredients have been selected by the National Toxicology Program (NTP) for toxicity and tumorigenicity studies. Due to the complexity of the chemical components present in plant extracts, there are no established methodologies for determining the mechanisms of toxicity (particularly tumorigenicity) induced by herbs, such as Gingko biloba leaf extract (GBE) and other herbal plant extracts. Consequently, the understanding of toxicity of herbal dietary supplements remains limited. We have proposed that application of DNA microarrays could be a highly practical initial approach for revealing biological pathways and networks associated with toxicity induced by herbal dietary supplements and the generation of hypotheses to address likely mechanisms. The changes in expression of subsets of genes of interest, such as the modulation of drug metabolizing genes, can be analyzed after treatment with an herbal dietary supplement. Although levels of gene expression do not represent fully the levels of protein activities, we propose that subsequent biochemical and genomic experiments based on these initial observations will enable elucidation of the mechanisms leading to toxicity, including tumorigenicity. This review summarizes the current practices of microarray analysis of gene expressions in animals treated with herbal dietary supplements and discusses perspectives for the proposed strategy.

Toxicity of kava kava

Kava is a traditional beverage of various Pacific Basin countries. Kava has been introduced into the mainstream U.S. market principally as an anti-anxiety preparation. The effects of the long-term consumption of kava have not been documented adequately. Preliminary studies suggest possible serious organ system effects. The potential carcinogenicity of kava and its principal constituents are unknown. As such, kava extract was nominated for the chronic tumorigenicity bioassay conducted by the National Toxicology Program (NTP). At present toxicological evaluation of kava extract is being conducted by the NTP. The present review focuses on the recent findings on kava toxicity and the mechanisms by which kava induces hepatotoxicity.

Herbal hepatotoxicity

There is appropriate concern about the potential risk for hepatotoxicity from herbal products because they are unregulated and therefore not standardized with regard to their contents. This is particularly the case for the crude herbals that are commonly formulated as a mixture, so that their ingredients may be ambiguous and even contain harmful contaminants. Presented here is an overview of the more commonly recognized herbal products that have been reported to be associated with liver injury. Although many of them are clearly implicated, there are some, particularly those identified solely through an occasional case report, for which the relationship is uncertain.

Safety review of kava (Piper methysticum) by the Natural Standard Research Collaboration

This systematic review discusses the proposed uses, dosing parameters, adverse effects, toxicology, interactions and mechanism of action of kava. The widespread concern regarding the potential hepatotoxicity of kava is discussed. A recommendation is made to consolidate and analyse available reports and to continue postmarket surveillance in an international repository to prevent duplicates and promote collection of thorough details at the time of each report so that any association with kava is clearly defined.

Hepatic injury due to traditional aqueous extracts of kava root in New Caledonia

Traditional aqueous kava extracts were the most probable cause of hepatitis in two patients presenting with markedly elevated transaminases and hyperbilirubinaemia. A consequent survey of 27 heavy kava drinkers in New Caledonia showed elevated gamma glutamyl transferase in 23/27 and minimally elevated transaminases in 8/27. We conclude that not only commercially available, but also traditionally prepared kava extracts may rarely cause liver injury. The increased activity of gamma glutamyl transferase in heavy kava consumers in the presence of normal or minimally elevated transaminases is probably not a sign of liver injury, but rather reflects an induction of CYP450 enzymes.