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Kava kava

Also listed as: Awa; Ava; Piper methysticum Yagona

• Overview
• Plant Description
• Medicinal Uses and Indications
• What's It Made Of?
• Available Forms
• How to Take It
• Precautions
• Possible Interactions
• Supporting Research

Overview

Kava kava ( Piper methysticum ) has been used as a ceremonial beverage in the Pacific Islands for thousands of years. It is believed to have originated in Melanesia, and been drunk for hundreds of years by native islanders.

The roots are chewed or ground into a pulp and added to cold water. The resulting thick brew, which has been compared to the social equivalent of wine in France, is typically offered to guests and dignitaries visiting the Pacific Islands.

In addition to its ceremonial purposes, kava is perhaps best known for its relaxing qualities. Kava is said to elevate mood, well-being, and contentment, and produce a feeling of relaxation. Several studies have found that kava may be useful in the treatment of anxiety, insomnia, and related nervous disorders.

Reports linking kava with liver damage has prompted regulatory agencies in Europe and Canada to warn consumers of the potential risks associated with this herb, and even to remove kava-containing products from the market. Based on these and other reports in the United States, the Food and Drug Administration (FDA) issued a consumer advisory in March of 2002 regarding the "rare" but potential risk of liver failure associated with kava-containing products. (See "Precautions" section.)

Plant Description

Kava root (which is used in medicinal preparations) comes from a tall shrub that grows in the islands of the Pacific Ocean. This shrub produces large, green, heart-shaped leaves that grow thickly on the branches. Long, slender flowers grow where the branches meet the stems. The roots look like bundles of woody, hairy branches.

Medicinal Uses and Indications

Due to the potential for liver injury, kava should be used only under the guidance of a qualified health care provider. It should not be taken for recreation use. Kava has been extensively studied, however, and evidence suggests that (under proper supervision and in proper dosages) it may be helpful for the following health problems:

Anxiety

Many clinical studies have found kava kava to be effective in treating symptoms associated with anxiety. In a review of seven scientific studies, researchers concluded that a standardized kava extract was significantly more effective than placebo in treating anxiety. Another study found that kava substantially improved symptoms after only 1 week of treatment. Results of clinical studies and the experiences of people using kava suggest that this herb may be as effective as certain anti-depressants and anti-anxiety medications. In fact, according to one recent study, kava and diazepam (a medication frequently used for anxiety) cause matching changes in brain wave activity, suggesting that they may work very similarly to calm the mind.

A review of 3 clinical studies for anxiety disorders, however, found no improvement when using kava supplements. No liver toxic effects were seen in the patients. Research on the use of kava for anxiety has decreased around the world due to the reports of liver toxicity.

A study in 2004 found that kava may improve mood and cognitive performance. A double-blind randomized placebo-controlled trial involving healthy individuals found that kava at a standardized dose of 300 mg seemed to improve tests related to cognitive performance and cheerfulness. Pharmaceutical drugs used in anxiety, such as benzodiazepines (including diazepam and alprazolam) tend to decrease cognitive function and impair the individual to a certain extent.

Some experts suggest that kava be considered for use when anxiety or stress accompany certain medical illnesses. For example, such feelings are not uncommon when being treated for cancer. In one survey, as many as 25% of prostate cancer patients felt depressed or anxious. The authors of this particular survey suggested that kava be considered to help relieve the feelings of such men with prostate cancer. Also, kava supplementation was reported to significantly reduce symptoms of generalized anxiety commonly in menopausal women or women experiencing PMS.

Insomnia

Short-term studies suggest that kava is effective for insomnia, particularly in improving sleep quality and decreasing the amount of time needed to fall asleep.

Other conditions

In addition to its anxiety-reducing (anxiolytic) and sedative properties, active compounds in kava are reputed to help prevent seizures and relieve muscle spasms. One study found that a standardized preparation of kava my help decrease side effects (called extrapyramidal) commonly seen when taking certain antipsychotic medications.

What's It Made Of?

The main active ingredients in kava root are called kavalactones (kavapyrones). The primary kavalactones (including kawain, dihydrokawain, and methysticum) have been extensively studied in laboratory and animal studies. These substances have been found to reduce convulsions, promote sleep, and relax muscles in animals. They also have pain-relieving properties. This may explain why chewing kava root tends to cause a temporary numbness and tingling sensation on the tongue.

Available Forms

In some parts of the world, whole kava roots are chewed for their medicinal value. Kava is also available in liquid form, as tinctures or standardized extracts, and powdered in capsules or tablets.

How to Take It

It is important to note that some people have developed severe liver damage, even liver failure, after ingesting kava. (See Precautions section.) It is recommended that this herb be taken under the supervision of a qualified health care provider. If you have pre-existing liver problems such as cirrhosis or hepatitis, do not take kava supplements.

Pediatric

There are no known scientific reports on the pediatric use of kava. Therefore, it is not currently recommended for children.

Adult

Standardized dosage: 150 - 300 mg, 1 - 3 times daily as needed for anxiety or nervousness, standardized to contain 30 - 70 % kavalactones. Most clinical trials have used the German kava extract WS 1490.

Kava dried root: 2.0 - 4.0 grams as a decoction (a preparation made by boiling down the herb in water), up to 3 times daily.

It may take 4 weeks before you notice improvement. Kava should not be taken for more than 3 months without a 2-week rest period.

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, contain components that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider qualified in the field of botanical medicine. This is particularly true for kava, given its potentially serious side effects as reported in a few individuals.

A few reports in the United States and abroad have linked kava ingestion with severe liver problems. Kava-containing products have been associated with at least 25 reports of liver-related injuries (including hepatitis, cirrhosis, liver failure, and death). In one case report, a 50-year-old man developed hepatitis after taking three to four kava extracts daily for tw2 o months. His condition quickly deteriorated, and he needed a liver transplant.

It must be noted, however, that the individuals experiencing liver damage may already have had liver damage before taking the kava supplements or may have taken kava in large doses and for longer than recommended. Some drank heavily, while others were taking prescription medications that may overworked the liver. It is important not to abuse kava or take it for recreational purposes, especially if you are consuming alcoholic beverages or taking prescription and non-prescription medications.

The FDA cautions individuals with liver disease or liver problems as well as those taking products (prescription and non-prescription medications, herbs, or supplements) that affect the liver, to consult a physician before taking kava-containing products. If you have taken kava and are experiencing symptoms of liver damage [such as yellow skin (jaundice), fatigue, abdominal pain, loss of appetite, nausea, vomiting, and joint pain], seek immediate medical attention.

Other side effects associated with kava appear to be mild and infrequent. Some reported adverse effects include allergic skin reactions (such as contact dermatitis), dizziness, drowsiness, restlessness, stomach upset, and tremors. Long-term use at high doses may cause flaky, dry, and yellowish discoloration of the skin, hair loss (alopecia), partial loss of hearing, and loss of appetite. Like alcohol, kava may also have intoxicating effects and should not be taken before operating a car or other machinery. In addition, when taken together with kava, alcohol increases the risk of impairment from this herb.

Pregnant or breastfeeding women should not take kava. Those undergoing surgery should also not take this herb as it may interfere with drugs used to induce anesthesia and prolong the effect of anesthesia. Kava should be stopped at least 24 hours prior to the scheduled surgery.

Possible Interactions

Do not take kava unless you are under the supervision of a qualified health care provider, especially if you are being treated for any disease. Do not take kava with any prescription and non-prescription medications.

Kava kava may interact with the following:

Anticonvulsants -- Kava may increase the effects of medications used to treat seizures.

Alcohol -- Do not use kava and alcohol together. The risk of impairment and the risk of liver damage are greatly increased.

Anxiety agents -- Kava may increase the effects of CNS depressants such as benzodiazepines, used for sleep disturbances or anxiety (particularly alprazolam), and barbiturates (such as pentobarbital) which are used for sleep disorders and seizures.

Antipsychotic medications -- Kava may increase the risk of side effects associated with phenothiazine medications (often used for the treatment of schizophrenia), including chlorpromazine and promethazine.

Levodopa -- There has been at least one report that kava may reduce the effectiveness of levodopa, a medication used to treat Parkinson's disease. Therefore, you should not take this herb if you are taking any medications containing levodopa or if you have Parkinson's disease.

Supporting Research

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• Review Date: 1/17/2007
• Reviewed By: Ernest B. Hawkins, MS, BSPharm, RPh, Health Education Resources; and Steven D. Ehrlich, N.M.D., private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.

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