Kava drinking in traditional settings: Towards understanding effects on cognitive function

BACKGROUND

Kava drinking is a tradition among Pacific Island people, although growing in popularity with other ethnicities. However, drinking substantial quantities of kava has raised concerns regarding physical manifestations of slow response and lack of precision in bodily control. These impairments can have significant consequences when after consuming large volumes of kava an individual makes a choice to drive.

AIMS

The objective of this study was to measure selected cognitive functions following high traditionally consumed kava volumes (greater than 2,000 mg of kavalactones) aimed at identifying potential risks for kava drink-drivers.

METHODS

The reaction and divided attention of 20 control participants was assessed against 20 active kava-drinking participants during and following a 6-hr kava session in a "naturalised" setting. Assessment measures were drawn from Vienna Test System-Traffic's test battery.

RESULTS/OUTCOMES

Results showed no statistical significant difference between control and active participants at any measurement point over a 6-hr testing period regardless that the movements and speech of the active participants were observed to slow as the test session and kava consumption progressed.

CONCLUSION

Inconsistencies between test results and observations during testing and by road policing officers demonstrate an urgent need for more research in this field.

Does kava cause hallucinations in Aboriginal populations in eastern Arnhem Land (Australia)?

Background: Isolated reports exist in the literature of hallucinations occurring as harmful outcomes of kava use. Kava's well-known mood-altering qualities contrast sharply with reports of such serious unwanted side effects. Arnhem Land Aboriginal people have used kava since 1982. Is there any evidence that kava use is associated with these kinds of effects in this population?

Objectives: This paper describes the context and circumstances for 18 individuals who were reported to have experienced hallucinations in a sample of the Miwatj population in eastern Arnhem Land (Northern Territory. NT) (see Clough. Cairney. Maruff, Burns & Currie. 2001). The role of kava use in these occurrences is discussed. Alcohol, tobacco, cannabis use and petrol sniffing as well as psycho-social factors were also noted in community health clinic files and health worker reports.

Results and conclusions: There was no evidence that hallucinations recorded in individuals were related to kava use. Instead, social and personal stress, pre-existing psychiatric conditions and excessive use of alcohol were more prominent. To describe the kinds of perceptual shifts experienced by kava users as hallucinations would seem imprudent without consideration of other environmental factors.

The health and social effects of drinking water-based infusions of kava: a review of the evidence

ISSUES

To review the evidence on the health and social effects of drinking kava; a water-based infusion of the roots of the kava plant.

APPROACH

Included all empirical studies of the effects of kava published 1987-2008 reporting health and social outcomes. Evidence appraised on study design (level of evidence) and standard epidemiological criteria for causality.

KEY FINDINGS

Causality indicated: scaly skin rash, weight loss, raised Gamma Glutamyl Transpeptidase liver enzyme levels, nausea, loss of appetite or indigestion; Association indicated but causality unclear: red sore eyes, impotence or loss of sexual drive, self-reported poor health, raised cholesterol, and loss of time and money, low motivation and 'slow/lazy' days following use, reduced alcohol consumption and related violence; Association hypothesised: fits or seizures, Melioidosis, Ischaemic Heart Disease, protective effects for cancer; No association indicated: cognitive performance; No association suggested: cognitive impairment, liver toxicity or permanent liver damage, other pneumonia; No association hypothesised: hallucinations.

IMPLICATIONS

The health and social implications of chronic kava drinking can be significant for individuals and communities, although most effects of even heavy consumption appear to be reversible when consumption is stopped.

CONCLUSION

An Australia-wide ban on commercial importation of kava has been in place since mid-2007, but there is no published literature to date on the impact of the ban.

Safety of ethanolic kava extract: Results of a study of chronic toxicity in rats

BACKGROUND

Recently, potential liver toxicity was discussed with the intake of kava extract preparations (Piper methysticum) as anxiolytic drugs. The aim of this study was to test chronic toxicity in rats by oral application of an ethanolic kava full extract.

METHODS

Wistar rats of both sexes were fed 7.3 or 73 mg/kg body weight of ethanolic kava extract for 3 and 6 months. The animals were examined for changes in body weight, hematological and liver parameters, and macroscopical and microscopical histological changes in the major organs.

RESULTS

No signs of toxicity could be found.

CONCLUSIONS

The results are in accordance with the medical experience regarding the use of kava preparations and the long tradition of kava drinking in the South Pacific island states. Specifically, the results do not back the suspicion of potential liver toxicity.

Labor analgesia for the parturient with herbal medicines use: what does an obstetrician need to know?

The use of herbal medicines in the developed world is widespread, and increasing. Herbal medicines, which include a wide spectrum of substances ranging from home-made teas to the national regulatory bodies-approved medicinal substances, are defined as plant-derived products that are used for medicinal and/or nutritional purposes. The use of herbal self-therapy is common in pregnancy, with many parturients consuming more than one agent at a time. Despite widespread use there has been surprisingly little research into the outcomes or the potential risks of using herbal therapies during pregnancy. As epidural analgesia is the most popular form of pain relief in labor, the potential for herbal remedies-related alterations in maternal hemodynamics (e.g., hypertension, tachycardia), and increased bleeding tendencies (e.g., spinal-epidural hematoma) remain a significant concern. Obstetricians and obstetric anesthesiologists must be familiar with the effects of herbal medicines and should specifically inquire about the use of herbal medicines during prenatal/preanesthetic assessment. This review article attempts to summarize current data on special considerations for labor analgesia in parturients with herbal medicines use.

Acute liver failure with renal impairment related to the abuse of senna anthraquinone glycosides

OBJECTIVE

To report a case of chronic ingestion of very large amounts of senna fruits as an herbal tea, possibly leading to severe hepatotoxicity.

CASE SUMMARY

A 52-year-old woman who had ingested, for >3 years, one liter of an herbal tea each day made from a bag containing 70 g of dry senna fruits, developed acute hepatic failure and renal impairment requiring intensive care therapy. The severity of the hepatic failure was reflected by the increase in prothrombin time (international normalized ratio >7) and the development of encephalopathy. Liver transplantation was discussed, but the patient ultimately recovered with supportive therapy. Renal impairment was consistent with proximal tubular acidosis, also with marked polyuria refractory to vasopressin administration. Suprisingly, large amounts of cadmium were transiently recovered in the urine.

DISCUSSION

Cassia acutifolia and angustifolia plants are widely used as laxatives. Their chronic abuse may be associated with serious manifestations, including fluid and electrolyte loss, with chronic diarrhea. Severe hepatotoxicity is unusual, but could be explained by the exposure of the liver to unusual amounts of toxic metabolites of anthraquinone glycosides (sennosides). An objective causality assessment suggests that hepatotoxicity was possibly related to senna laxative abuse. Regarding nephrotoxicity, there are no available human data on sennosides, while experimental models suggest that anthraquinone derivatives may also accumulate in the kidneys. The finding of high urinary concentrations of cadmium would suggest contamination of the herbal tea by metals, but this hypothesis could not be verified.

CONCLUSIONS

Ingestion of large doses of senna laxatives may expose people to the risk of hepatotoxicity.

Implications of herbal alternative medicine for electroconvulsive therapy

OBJECTIVES

To clarify the implications of herbal alternative medicine use during electroconvulsive therapy (ECT).

BACKGROUND

A substantial proportion of patients with mental disorders report frequent use of herbal alternative medicines. Our current understanding of the biology of such remedies suggests that they may have implications for ECT practice.

METHODS

We conducted electronic literature searches using Medline (via PubMed), Cochrane Database of Systematic Reviews, ACP Journal Club, PsychINFO, Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials from their inception to April 2003. The search items were five selected herbal alternative medicines (Ginkgo biloba, ginseng, St. John's wort, valerian, kava-kava) in combination with the terms "drug interaction," "adverse effects," "side effects," "adverse drug reactions," "safety," and "toxicity." All data were included regardless of whether they were case reports, case series, clinical trials, or reviews.

RESULTS

Our literature review revealed several potential effects of herbal alternative medicines upon ECT outcome.

CONCLUSIONS

The growing use of herbal alternative medicine by patients with psychiatric illness may have implications for ECT practice. Our current knowledge is sparse and incomplete, however, indicating the need for more research.

Kava kava: examining new reports of toxicity

Before 1998, extracts of kava kava, Piper methysticum, were considered to be very safe alternatives to anxiolytic drugs and to possibly exert a wide range of other benefits. Major reviews published through the end of 2002 continued to confirm kava's safety and efficacy. Nevertheless, by January 2003 kava extracts had been banned in the entire European Union and Canada, and were subject to cautions and advisories by the US FDA as a result of 11 cases of hepatic failure leading to liver transplants, including four deaths. A total of 78 cases of hepatotoxicity reputedly linked to kava ingestion are available for review from various databases. Of these adverse events, four probably are linked to kavalactones taken alone and another 23 are potentially linked to kava intake, but also involve the concomitant ingestion of other compounds with potential hepatotoxicity. Three possible mechanisms for kavalactone hepatotoxicity are known: inhibition of cytochrome P450, reduction in liver glutathione content and, more remotely, inhibition of cyclooxygenase enzyme activity. The direct toxicity of kava extracts is quite small under any analysis, yet the potential for drug interactions and/or the potentiation of the toxicity of other compounds is large. Presently, kava toxicity appears to be "idiosyncratic." The risk-to-benefit ratio of kava extracts, nevertheless, remains good in comparison with that of other drugs used to treat anxiety.

Serious psychiatric and neurological adverse effects of herbal medicines -- a systematic review

OBJECTIVE

Psychiatric and neurological patients frequently try herbal medicines often under the assumption that they are safe. The aim of this systematic review was to provide a summary of recent data on severe psychiatric and neurological adverse effects of herbal remedies.

METHOD

Computerized literature searches were carried out to identify all reports of psychiatric and neurological adverse effects associated with herbal medicines. These data were subsequently extracted, validated and summarized in narrative and tabular form.

RESULTS

Numerous case reports comprise a diverse array of adverse events including cerebral arteritis, cerebral oedema, delirium, coma, confusion, encephalopathy, hallucinations, intracerebral haemorrhage, and other types of cerebrovascular accidents, movement disorders, mood disturbances, muscle weakness, paresthesiae and seizures. Several fatalities are on record. They are caused by improper use, toxicity of herbal ingredients, contamination and adulteration of preparations and herb/drug interactions.

CONCLUSION

Herbal medicines can cause serious psychiatric and neurological adverse effects.

A systematic review of the safety of kava extract in the treatment of anxiety

This paper systematically reviews the clinical evidence relating to the safety of extracts of the herbal anxiolytic kava (Piper methysticum). Literature searches were conducted in four electronic databases and the reference lists of all papers located were checked for further relevant publications. Information was also sought from the spontaneous reporting schemes of the WHO and national drug safety bodies and ten manufacturers of kava preparations were contacted. Data from short-term post-marketing surveillance studies and clinical trials suggest that adverse events are, in general, rare, mild and reversible. However, published case reports indicate that serious adverse events are possible including dermatological reactions, neurological complications and, of greatest concern, liver damage. Spontaneous reporting schemes also suggest that the most common adverse events are mild, but that serious ones occur. Controlled trials suggest that kava extracts do not impair cognitive performance and vigilance or potentiate the effects of central nervous system depressants. However, a possible interaction with benzodiazepines has been reported. It is concluded that when taken as a short-term monotherapy at recommended doses, kava extracts appear to be well tolerated by most users. Serious adverse events have been reported and further research is required to determine the nature and frequency of such events.

The peri-operative implications of herbal medicines

An increasing number of patients are taking herbal medicines such as echinacea, garlic, ginkgo biloba, ginseng, St John's Wort, valerian, ephedra, kava, grapefruit juice and ginger. Although these herbal medications are considered 'natural' products that may have some benefits, adverse effects such as increased bleeding tendencies and drug interactions are associated with their use. Surgeons and anaesthetists may be unaware of their patients' use of these medications because it is common for patients not to disclose their use of this form of medication, and both surgeons and anaesthetists often fail to enquire about their use. Anaesthetists and surgeons must be familiar with the effects of herbal medicines and should specifically enquire about the use of herbal medicines during pre-operative assessment. Currently available data suggest that all herbal medicines should be ceased 2 weeks before surgery.

Kava--the unfolding story: report on a work-in-progress

This paper, originated as a submission (now updated) to the U.K. Medicines Control Agency and Committee of Safety of Medicines (CSM) on January 11, 2002, in response to a report circulated by the German Federal Institute for Drugs and Medical Products (German initials are BfArM), a compilation of which is summarized in Appendix 2. This agency issued notification in late November 2001 of some thirty adverse events associated with the use of concentrated standardized preparations of kava (Piper methysticum, Forst. f.) reported from Germany and Switzerland. An analysis of the summary of the BfArM case reports (see Appendix 2) shows that these contain duplications among the cases cited. The original submission that was sent to the CSM January 2002 has been updated to the version published here. This new version was completed in April 2002. As a result of the alert from BfArM, the evaluation of kava's safety is now occurring on a worldwide basis and, being that this a matter of considerable importance to the public, the health care community, and regulatory authorities as well as to kava farmers throughout Polynesia, it is it important to depict this progress report. As such, this updated report does not provide final answers. The material released by the BfArM is lacking in detail; however, it is hoped that this report will shed light on the kava controversy. It is anticipated that there will be further updates shortly. This report, prepared on behalf of the Traditional Medicines Evaluation Committee, a subcommittee of the European Herbal Practitioners Association, argues that many of the adverse events cited by the BfArM should not be attributed to kava. In addition, the report states that the properties of concentrated standardized kava extracts - as opposed to preparations that closely approximate those created for traditional use - contribute to causing adverse events. This report proposes a number of simple measures that will ensure that safe kava preparations may continue to be available in the United Kingdom.