Medically reviewed: June 7, 2018
Medically reviewed on June 7, 2018
What is Kava?
The dried rhizome and roots of P. methysticum, a large shrub widely cultivated on many Pacific islands, including Hawaii, Tahiti, and New Guinea, are consumed in various forms as kava. The plant can grow as tall as 3 m, has large, heart-shaped leaves, and is propagated only by root cuttings. Many cultivars of kava are recognized, and the rootstock color ranges from white to dark yellow, depending on the amount of kavalactones present.
Piper methysticum Forst.f.
Kava, kawa, kava-kava, awa, yangona, kawain, kavain, ava, kava pepper, intoxicating pepper, kava root, kew, sakau, tonga, wurzelstock, rauschpfeffer.
What is it used for?
The kava beverage is prepared from the plant's roots, which are chewed or pulverized and then steeped in water or coconut milk. The cloudy mixture is filtered and served at room temperature. Kava has been an important part of Pacific island ceremonial cultures for many centuries, with elaborate rituals related to its consumption. Its main use has been to induce a relaxed state in ceremony participants by initially causing a numbing and astringent effect in the mouth, followed by sedating and muscle relaxant effects. Eventually, a state of sleep is induced and no hangover effects are experienced. The kava beverage has been used to symbolize respect and hospitality for visiting dignitaries, with traces of kava extract identified on archaeological artifacts from the Fiji islands.
Research into the use of kava has been conducted since the late 19th century. In the early 1900s, kava was used as a diuretic and for gonorrhea and nervous disorders. It has been one of the top botanical sellers in the United States and Europe for anxiety and sleep disorders. However, many countries have regulated its sale because of reports of liver toxicity. In 2002, the US Food and Drug Administration issued a consumer advisory warning of the potential for liver injury.
A number of meta-analyses and systematic reviews of kava use in anxiety have found in favor of kava over placebo, but results are not consistent. Kava has also been studied for effects on mental function and for potential cancer applications. However, concerns over liver toxicity have limited clinical studies.
What is the recommended dosage?
A maximum daily dose of kavalactones 250 mg is suggested to avoid potential liver toxicity. Studies in children are lacking, and use is not recommended.
Kava and kava-containing products are not recommended for use in children or in patients with liver disease. Kava should also be used cautiously in patients with kidney disease, blood disorders, Parkinson disease, or depression.
Documented adverse effects. Avoid use.
Kava extracts have been shown to interfere with some enzymes; however, specific reports on the metabolism of drugs are sparse. Case reports exist on interactions with alprazolam, alcohol, barbiturates, and levodopa. Coadministration of kava with haloperidol, risperidone, and metoclopramide, among other drugs, may be associated with adverse reactions.
Heavy kava use may cause a scaly skin rash. A variety of adverse reactions, including visual disturbances, urinary retention, GI discomfort, worsening of Parkinson disease, neurological effects, and muscle disorders, have been reported.
Rare cases of severe liver toxicity have been reported.