Effect of kava extract on vagal cardiac control in generalized anxiety disorder: preliminary findings

Health policy versus kava (Piper methysticum): Anxiolytic efficacy may be instrumental in restoring the reputation of a major South Pacific crop

ETHNOPHARMACOLOGICAL RELEVANCE

Kava (Piper methysticum G. Forst. f.) is by far the most important plant used in the islands of Melanesia, Polynesia and Micronesia for its relaxing effects. Kava drinking is a pillar of South Pacific societies and is also the foundation of their economies. Preparations of kava extract as herbal medicinal drugs were banned in Germany in 2002 and again in 2019, with dramatic consequences for the South Pacific economies. In 2002, the major regulatory argument for the ban of kava was safety issues. In 2019, the assessment report of the European Medicines Agency's Herbal Medicinal Product Committee (HMPC) justified a negative benefit-to-risk ratio by a supposed lack of efficacy of ethanolic extracts for an indication of which kava extract preparations never had an approval. In this HMPC report the efficacy in the approved indications 'nervous anxiety, tension and restlessness' was attributed to the extract branded as 'WS 1490', which was assumed to have been prepared with acetone as an extraction solvent. In addition to this change of indication and the attribution of efficacy to acetone kava extract alone, the German health authorities and the HMPC still refuse to discuss quality issues as a likely factor impacting drug safety. The first case reports of liver toxicity were observed with an acetone extract in a timely relationship with the introduction of 'two-day kava' instead of 'noble kava' as used in ethanolic kava extracts.

AIM OF THE STUDY

The correlation between clinical benefits and the type of extract preparation was examined.

METHODS

In order to identify the types of kava material and extracts used in clinical trials, the respective publications were compared with regulatory databases and protocols of a German regulatory advisory board.

RESULTS AND CONCLUSIONS

The comparison reveals inconsistencies in the regulatory decisions. In all studies with WS 1490, the evidence points to the use of an ethanolic extract. The efficacy of kava extract for the approved indication was clearly demonstrated. The HMPC report and the recent renewed German regulatory ban of kava therefore require major revision, which should include the impact of the use of "two-day kava" on drug safety. Such a revision could contribute to restoring the reputation of "noble kava" on the international markets.

Piper Species: A Comprehensive Review on Their Phytochemistry, Biological Activities and Applications

Piper species are aromatic plants used as spices in the kitchen, but their secondary metabolites have also shown biological effects on human health. These plants are rich in essential oils, which can be found in their fruits, seeds, leaves, branches, roots and stems. Some Piper species have simple chemical profiles, while others, such as Piper nigrum, Piper betle, and Piper auritum, contain very diverse suites of secondary metabolites. In traditional medicine, Piper species have been used worldwide to treat several diseases such as urological problems, skin, liver and stomach ailments, for wound healing, and as antipyretic and anti-inflammatory agents. In addition, Piper species could be used as natural antioxidants and antimicrobial agents in food preservation. The phytochemicals and essential oils of Piper species have shown strong antioxidant activity, in comparison with synthetic antioxidants, and demonstrated antibacterial and antifungal activities against human pathogens. Moreover, Piper species possess therapeutic and preventive potential against several chronic disorders. Among the functional properties of Piper plants/extracts/active components the antiproliferative, anti-inflammatory, and neuropharmacological activities of the extracts and extract-derived bioactive constituents are thought to be key effects for the protection against chronic conditions, based on preclinical in vitro and in vivo studies, besides clinical studies. Habitats and cultivation of Piper species are also covered in this review. In this current work, available literature of chemical constituents of the essential oils Piper plants, their use in traditional medicine, their applications as a food preservative, their antiparasitic activities and other important biological activities are reviewed.

Kava for Generalized Anxiety Disorder: A Review of Current Evidence

BACKGROUND

Generalized anxiety disorder (GAD) is a chronic and debilitating condition characterized by persistent and overpowering anxiety. Treatment of GAD with antidepressants and benzodiazepines is only moderately effective and not free from side effects. Kava (Piper methysticum) has been explored as a potential phytotherapeutic option for GAD.

OBJECTIVES

To perform a systematic review and meta-analysis of the available evidence on Kava as a treatment for GAD.

METHODS

Systematic search of English-language publications from major databases for clinical trials reporting the effects of Kava for the treatment of GAD.

RESULTS

Twelve articles were included in this review. Evidence supporting Kava as an effective treatment for GAD was found in two placebo-controlled trials and a reference-controlled trial. One negative trial demonstrated that Kava was not more effective than placebo. Meta-analyses of the results of three placebo-controlled trials (n = 130) favored Kava for GAD treatment with effect sizes between 0.59 and 0.99 (standard mean difference) without reaching statistical significance. Kava is an appealing treatment option to GAD patients who are more attune to natural remedies or lifestyle approaches to reduce stress. Positive patient experiences and improvement of vagal cardiac control due to Kava treatment were also reported in the literature. Kava is safe and well tolerated for short-term (4-8 weeks) therapeutic use at a dosage of 120-280 mg per day of Kavalactones, regardless of dosage schedule.

CONCLUSIONS

Current evidence, although promising, is insufficient to confirm the effect of Kava for GAD treatment beyond placebo. New evidence is expected from a large, multisite ongoing trial.

Dietary and botanical anxiolytics

Drugs used to treat anxiety have many negative side effects including addiction, depression, suicide, seizures, sexual dysfunction, headaches and more. Anxiolytic medications do not restore normal levels of neurotransmitters but instead manipulate the brain chemistry. For example, selective serotonin reuptake inhibitors (SSRIs) prevent the reuptake of serotonin from the synapse allowing serotonin to remain in the area of activity for a longer period of time but does not correct the lack of serotonin production. Benzodiazepines, such as Valium and Xanax^®, stimulate GABA receptors, thus mimicking the calming effects of GABA but again do not fix the lack of GABA production. Often, the brain becomes accustomed to these medications and they often lose their effectiveness, requiring higher doses or different drugs. In contrast to anxiolytic drugs, there are herbs and nutrients which can stimulates neurotransmitter synthesis and more naturally effect and even adjust brain chemistry in the absence of many of the side effects experienced with drugs. Therefore this paper explores several herbal and nutritional approaches to the treatment of anxiety.

Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review

BACKGROUND

Over the past several decades, complementary and alternative medications have increasingly become a part of everyday treatment. With the rising cost of prescription medications and their production of unwanted side effects, patients are exploring herbal and other natural remedies for the management and treatment of psychological conditions. Psychological disorders are one of the most frequent conditions seen by clinicians, and often require a long-term regimen of prescription medications. Approximately 6.8 million Americans suffer from generalized anxiety disorder. Many also suffer from the spectrum of behavioural and physical side effects that often accompany its treatment. It is not surprising that there is universal interest in finding effective natural anxiolytic (anti-anxiety) treatments with a lower risk of adverse effects or withdrawal.

METHODS

An electronic and manual search was performed through MEDLINE/PubMed and EBSCO. Articles were not discriminated by date of publication. Available clinical studies published in English that used human participants and examined the anxiolytic potential of dietary and herbal supplements were included. Data were extracted and compiled into tables that included the study design, sample population, intervention, control, length of treatment, outcomes, direction of evidence, and reported adverse events.

RESULTS

A total of 24 studies that investigated five different CAM monotherapies and eight different combination treatments and involved 2619 participants met the inclusion criteria and were analyzed. There were 21 randomized controlled trials and three open-label, uncontrolled observational studies. Most studies involved patients who had been diagnosed with either an anxiety disorder or depression (n = 1786). However, eight studies used healthy volunteers (n = 877) who had normal levels of anxiety, were undergoing surgery, tested at the upper limit of the normal range of a trait anxiety scale, had adverse premenstrual symptoms or were peri-menopausal, reported anxiety and insomnia, or had one month or more of elevated generalized anxiety. Heterogeneity and the small number of studies for each supplement or combination therapy prevented a formal meta-analysis. Of the randomized controlled trials reviewed, 71% (15 out of 21) showed a positive direction of evidence. Any reported side effects were mild to moderate.

CONCLUSIONS

Based on the available evidence, it appears that nutritional and herbal supplementation is an effective method for treating anxiety and anxiety-related conditions without the risk of serious side effects. There is the possibility that any positive effects seen could be due to a placebo effect, which may have a significant psychological impact on participants with mental disorders. However, based on this systematic review, strong evidence exists for the use of herbal supplements containing extracts of passionflower or kava and combinations of L-lysine and L-arginine as treatments for anxiety symptoms and disorders. Magnesium-containing supplements and other herbal combinations may hold promise, but more research is needed before these products can be recommended to patients. St. John's wort monotherapy has insufficient evidence for use as an effective anxiolytic treatment.

What should medical practitioners know about the role of alternative medicines in cardiovascular disease management?

Alternative medications as a term call up many different meanings, significance, and perceptions to various medical practitioners. Some are good; others are bad. A wide range of alternative medications with relevance or connection to cardiovascular (CV) disease have been considered. While many are worthless, others have definite benefit, and at least one, chelation therapy, is associated with definite harm, significant risk, no benefit, and enrichment of the practitioners who prescribe it. The issues concerning alternative therapies will likely never be studied with randomized clinical trials due to the lack of a profit motive on the part of pharmaceutical companies--only rarely do other institutions, such as the National Institutes of Health, support medicinal studies. Basic knowledge of alternative therapies is essential for the CV specialist and other practicing physicians and other practitioners, since at least a few of their patients will take these medications regardless of medical advice. The result is that a number of these alternative medications will then interact with conventional CV medications, many times unfavorably.

Herbal medicines in the treatment of psychiatric disorders: a systematic review

This paper reports a critical review of 27 herbal medicines and formulas in treating a broad range of psychiatric disorders (in addition to anxiety and depression), including obsessive-compulsive, seasonal affective, bipolar depressive, psychotic, phobic and somatoform disorders. Ovid Medline, Pubmed and the Cochrane Library were searched for pharmacological and clinical evidence of herbal medicines with psychotropic activity. A forward search of later citations was also conducted. Whilst substantial high-quality evidence exists for the use of kava and St John's wort in the treatment of anxiety and depression respectively, currently there is insufficient robust clinical evidence for the use of many other herbal medicines in psychiatric disorders. Phytotherapies which potentially have significant use in psychiatry, and urgently require more research are Rhodiola rosea (roseroot) and Crocus sativus (saffron) for depression; Passiflora incarnata (passionflower), Scutellaria lateriflora (scullcap) and Zizyphus jujuba (sour date) for anxiety disorders; and Piper methysticum (kava) for phobic, panic and obsessive-compulsive disorders. While depression and anxiety are commonly researched, the efficacy of herbal medicines in other mental disorders requires attention. The review addresses current issues in herbal psychotherapy: herbal safety, future areas of application, the relationship of herbal medicine with pharmaceuticals and the potential prescriptive integration of phytomedicines with synthetic psychotropic medicines. Particular attention is given to clinical and safety issues with St John's wort and kava.

Kava in generalized anxiety disorder: three placebo-controlled trials

In this study, we evaluated the efficacy and safety of kava kava (Piper methysticum) in generalized anxiety disorder. Data were analyzed from three randomized, double-blind, placebo-controlled trials of kava, including one study with an active comparator (venlafaxine), in adult outpatients with DSM-IV generalized anxiety disorder. The pooled sample (n=64) included the following number of participants: kava, n=28; placebo, n=30; and venlafaxine, n=6. Given the comparability of the study designs, the data comparing kava and placebo were then pooled for further efficacy and safety analyses. No significant differences were observed between the treatment groups in any of the trials. In the pooled analyses, no effects were found for kava, while a significant effect in favor of placebo was observed in participants with higher anxiety at baseline. No evidence of hepatotoxicity was found with kava, and all of the treatments were well tolerated. Findings from these three controlled trials do not support the use of kava in DSM-IV generalized anxiety disorder.

Ethnicity and Use of Alternative Products in Psychiatric Patients

The use of herbal and natural products for medical purposes is common in all human civilizations, and use in Western societies has grown considerably in recent years. However, differences in usage patterns between different ethnic groups are yet to be delineated. The current study examined the frequency and type of complementary/alternative medications used by a sample of 453 rural psychiatric outpatients of two different ethnic groups. The products were classified as "natural" (herbal products requiring some preparation before consumption) and "processed" (products in "ready-to-use" form). There were significant ethnic differences in usage patterns of the various preparations: Hispanics, relative to Caucasians, were twice as likely to use natural products, whereas Caucasians were more likely than Hispanics to use processed products. The symptoms addressed were predominantly psychiatric, with natural products, and nonpsychiatric, with processed products. These results may increase awareness among healthcare providers regarding the usage frequency of such complementary/alternative medications products and the different usage patterns across ethnic groups.

Therapeutic potential of kava in the treatment of anxiety disorders

Anxiety disorders are among the most common psychiatric disorders that affect all age groups of the general population. Currently, the preferred treatment is with pharmacological drugs that have antidepressant or anti-anxiety properties. However, these agents have numerous and often serious adverse effects, including sedation, impaired cognition, ataxia, aggression, sexual dysfunction, tolerance and dependence. Withdrawal reactions on termination after long-term administration are also a major limiting factor in the use of these agents. Herbal remedies, including kava (Piper methysticum), have been shown to be effective as alternative treatments, at least in mild to moderate cases of anxiety. Kava is a social and ceremonial herb from the South Pacific. It is available in the west as an over-the-counter preparation. Its biological effects, due to a mixture of compounds called kavalactones, are reported to include sedative, anxiolytic, antistress, analgesic, local anaesthetic, anticonvulsant and neuroprotective properties. The pharmacological properties of kava are postulated to include blockade of voltage-gated sodium ion channels, enhanced ligand binding to gamma-aminobutyric acid (GABA) type A receptors, diminished excitatory neurotransmitter release due to calcium ion channel blockade, reduced neuronal reuptake of noradrenaline (norepinephrine), reversible inhibition of monoamine oxidase B and suppression of the synthesis of the eicosanoid thromboxane A(2), which antagonises GABA(A) receptor function. Clinical studies have shown that kava and kavalactones are effective in the treatment of anxiety at subclinical and clinical levels, anxiety associated with menopause and anxiety due to various medical conditions. Until recently, the adverse effects attributed to kava use were considered mild or negligible, except for the occurrence of a skin lesion. This disorder, called kava dermopathy, occurs only with prolonged use of large amounts of kava and is reversible on reduced intake or cessation. Rare cases of interactions have occurred with pharmaceutical drugs that share one or more mechanisms of action with the kavalactones. In the past few years, about 35 cases of severe liver toxicity associated with kava intake have been reported in Europe and the US. However, a direct causal relationship with kava use has been difficult to establish in the majority of the cases, and there is insufficient evidence to implicate kava as the responsible agent. Nevertheless, until further research clarifies any causality, kava should be used with caution.