Synonyms/Common Names/Related Substances:

• (+) -dihydrokawain-5-ol, 11-methoxy-5, 5-hydroxydihydrokawain, 6-dihydroyangonin, antares, ava, ava pepper, ava pepper shrub, ava root, awa, bornyl cinnamate, cavain, Fijian kava, flavokavines A and B, gea, gi, grog, intoxicating long pepper, intoxicating pepper, kao, kava kava extract LI 140, kava kava rhizome, kava root, kavain, kavakava, kavalactones, kavapiper, kavapyrones, kavarod, kavasporal forte, kave-kave, kawa, kawa kawa, kawa pepper, Kawa Pfeffer, kew, LI150, long pepper, Macropiper latifolium, malohu, maluk, maori kava, meruk, milik, olanzapine, pepe kava, Piper methysticum, piperis methystici rhizoma, pipermethystine, Rauschpfeffer, rhizoma piperis methystici, Rhizome Di Kava-Kava sakaua, risperidone, sakau, tonga, WS 1490, wurzelstock, yagona, yangona, yaqona, yongona.

Clinical Bottom Line/Effectiveness

Brief Background

• Kava beverages, made from dried roots of the shrub Piper methysticum, have been used ceremonially and socially in the South Pacific for hundreds of years and in Europe since the 1700s. The drink is reported to have pleasant mild psychoactive effects (1), similar to alcoholic beverages. Recreational use of kava has spread over the last 20 years to Aboriginal communities in Australia (2), where it is often consumed in combination with alcohol (3). In Fiji, kava is still used today during welcome ceremonies for local and international political and religious dignitaries. In 2002, local annual sales in Fiji have been reported in the range of $30 million, with exports amounting up to $17 million. Kava generated almost EUR 100 million in 2001 (IKC Report).
• Several well-conducted human trials and meta-analysis (4;​5;​6;​7) have shown that kava can effectively treat anxiety, with effects observed after as few as 1-2 doses, and progressive improvements over 1-4 weeks. Preliminary evidence suggests that kava's effectiveness may be equivalent to benzodiazepines. The pharmaceutical preparations of kava were widely used in Europe and the United States as anxiolytics, but they have since been withdrawn in several European markets and Canada due to safety concerns (8;​9;​10;​11;​12;​13).
• Although kava has been studied as a possible treatment for insomnia, many experts believe that kava is neither sedating nor tolerance-forming in recommended doses. Some trials report occasional mild sedation, although preliminary data from small studies suggest a lack of neurological-psychological impairment. Chronic or heavy use of kava has been associated with cases of neurotoxicity, pulmonary hypertension, and dermatologic changes. However, most human trials have been shorter than two months, with the longest study being six months in duration (14).
• In addition, there is widespread concern regarding the potential hepatotoxicity of kava (15;​16;​17;​18;​19;​20;​21;​22;​23;​24;​25;​26). More than 30 cases of liver damage have been reported in Europe, including hepatitis (27;​28;​29), cirrhosis, fulminant liver failure (30;​31), and reports of death (32;​33), although some authors have challenged these reports and maintained that kava is safe in most individuals at recommended doses (34;​35). It is not clear what dose or duration of use may be correlated with the risk of liver damage. This remains an area of controversy, and it is unclear if the safety profile of kava is comparable to other agents used in the management of anxiety.

Dosing/Toxicology

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Precautions/Contraindications

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Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

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Mechanism of Action

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History

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Evidence Table

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Evidence Discussion

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Products Studied

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Author Information

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References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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