Kava has been shown in more than a dozen placebo-controlled studies to be effective with good tolerability for treatment of generalized anxiety, with some evidence for stress, depression and insomnia. Kava is generally safe for short-term use but can in rare cases cause catastrophic damage to the liver. Thus, its use is very controversial, and the sources are split four to three on whether it should ever be recommended.
Mental Health Implications
Seven sources confirm the beneficial uses of kava as a mild intoxicant and analgesic, and for treatment of generalized anxiety, depression, stress, tension, agitation, agoraphobia, specific other phobias, generalized anxiety disorder, adjustment disorder, menopausal symptoms and insomnia. But Brown et al. caution that the benefits are "modest," and all sources caution about the danger of liver damage. There is no proof that kava is effective for treatment of severe anxiety. No published studies have yet tested kava's efficacy for panic disorders. Kava has not been found effective for adjunctive use, should not be used with MAOIs, and should only be used with tricyclics or SSRIs after careful coordination with the prescribing physician.
Kava has the potential to interact with several drugs and medications. It is vitally important to discuss kava use with any prescribing physician.
Alcohol, other sedatives, muscle relaxants, dopamine, haloperidol, acetaminophen, and benzodiazepines. Taking kava with alcohol, other sedatives, or muscle relaxants can result in additive effects up to and including coma. Kava may interact with several drugs, including drugs used for Parkinson's disease and benzodiazepines used for anxiety. Alcohol or acetaminophen (Tylenol), which may injure the liver, should never be used with kava. Kava may interfere with the effects of dopamine and drugs that are similar to dopamine and may worsen the neurological side effects of drugs that block dopamine, such as haloperidol (Haldol).
Psychotropics and anesthesia. Kava may have chemical properties similar to monoamine oxidase inhibitors (MAOIs), and may be additive to the effects of MAOI antidepressants, such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate). Thus, kava should never be used with MAOIs. Adjunctive use with other psychotropic drugs, including tricyclic antidepressants and SSRIs, has not been tested, but should not be attempted without careful coordination with the prescribing physician. Kava may cause excessive drowsiness when taken with SSRI antidepressant drugs such as fluoxitine or sertraline. Kava may also cause anesthesia to last longer and use should be carefully coordinated with the prescribing physician or anesthesiologist.
Anti-cancer and birth control drugs. Kava may also interact with anti-cancer and birth control drugs.
Caution: Liver Toxicity: Reports from health authorities in Germany, Switzerland, France, Canada, and the United Kingdom have linked kava use to at least 30 cases of liver toxicity, including hepatitis, cirrhosis, and liver failure. Kava is banned in Germany, Canada and Switzerland. The U.S. FDA issued a consumer advisory in 2002, which is still in effect. The FDA cautions: Persons who have liver disease or liver problems, or persons who are taking drug products that can affect the liver, should consult a physician before using kava-containing supplements.
Of the consulted sources, Consumer Reports is the most directive: Based on the 2002 FDA warning, kava is one of 12 supplements that Consumer Reports advises that you should avoid. Brown et al. also do not recommend kava, and Fugh-Berman no longer recommends it, because of the catastrophic liver damage associated with its use in the cases noted by the FDA. Four sources still recommend careful use of kava. Lake and Spiegel, Mischoulon and Rosenbaum, the Natural Standard, and Weil counsel that kava should be avoided in individuals with a history of liver disease or alcohol use, and in those who are taking concurrent medications with potential liver toxicity. Mischoulon and Rosenbaum conclude: "Kava should be prescribed and used with great caution." Use of kava is not recommended to exceed three months.
More research pinpointing risk factors could modify these recommendations, since liver toxicity appears to be extremely rare, and bad experience with other anxiolytics could prompt a trial of kava if the risk factors appear to be low, with proper medical supervision. Pregnancy, lactation or child use would appear not to impose a separate challenge.
Caution. The risk of liver damage is substantial and may be irreversible, even though it appears to be rare.
For detailed information on Kava and other treatments, download the full review.