Kava

Kava comes from the root of a shrub that grows in the South Pacific. It is ingested as a tea or in capsule form. The active ingredients are thought to be kavalactones.

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People use kava mostly as a sedative, to reduce anxiety, restlessness, or stress, and to aid sleep. Some people use kava for asthma, menopausal symptoms, and urinary tract infections.

Some scientific evidence supports use of kava to reduce anxiety and as a sleep aid.

Some people in both Europe and the United States who have taken kava developed liver toxicity (including liver failure). Thus, the Food and Drug Administration (FDA) has required a warning label on kava products, and safety is under continuing surveillance. Some researchers believe the liver toxicity may be due to inappropriate preparation or poor quality raw material contaminated with mold that contains liver toxins.

When kava is prepared traditionally (as tea) and used in high doses or over long periods of time, a scaly rash (kava dermopathy), vision problems, changes in blood (such as an increased number of red blood cells), and changes in movement disorders (such as worsening of Parkinson disease) may occur.

Kava should be stopped at least 2 weeks before surgery to clear it from the system because kava can cause excessive sedation when anesthetics or other sedatives are given.

Kava may prolong the effect of other sedatives (such as barbiturates or alcohol) and affect driving or other activities requiring alertness. Kava may interfere with the effects of dopamine, a neurotransmitter that is in short supply in Parkinson disease. As a result, it may decrease the benefit of levodopa, a drug used to treat Parkinson disease. Kava may intensify the effect of anesthetics.

Kava use is not recommended. Kava can have serious side effects. There are safer and probably more effective methods, drugs, or alternative treatments for relieving anxiety and promoting sleep. People who take kava should be counseled to discontinue its use 2 weeks before surgery.