Kava Kava (Piper methysticum)

Kava Kava: Medical Uses

Kava kava is used to improve mental function and for anxiety disorders, hot flashes, and anxiety and mild depression associated with menopause.

Historical Uses

Kava comes from a Greek word meaning “intoxicating.” The herb has been used in Polynesian countries to make a ceremonial drink.

Growth

This tropical, perennial shrub is a member of the pepper family and is native to Oceania.

Part Used

• Root

Major Chemical Compound

• Kavalactones

Kava Kava: Clinical Uses

Kava kava is used to improve mental function and for nonpsychotic anxiety disorders, hot flashes, and anxiety and mild depression associated with menopause. It is approved by the German Commission E for “anxiety, stress, and restlessness”.

Mechanism of Action

Kava kava has sedative, analgesic, anticonvulsant, and muscle relaxant effects and acts on the limbic system. Its action is different from that of aspirin, morphine, and benzo-diazepines. Little information is currently available on kavalactones.

For anxiety:

Standardized extract: 70 mg kavalactones two to three times daily.

Capsules or tablets: 400 to 500 mg up to six times daily.

Tincture (1:2): 15 to 30 drops up to three times daily. Tincture drops may be added to a small amount of water or juice. Recommended use up to 3 months. Total kavalactones should not exceed 300 mg per day.

Tea: Does not extract important kavalactones.

Side Effects

Side effects are rare. They include liver damage, yellowing of the skin with chronic abuse, and depression of the nervous system.

Contraindications

• Kava kava is contraindicated in patients who have depression of biological origin.

• Do not give kava kava to a patient who will be driving or operating heavy machinery. In one reported case, a man who drank more than 8 cups of kava kava was charged with driving under the influence.

• This herb is contraindicated in children under age 18.

Herb-Drug Interactions

Kava kava may potentiate the effects of alcohol and other central nervous system depressants. Additive effects have been noted with alprazolam. The efficacy of levodopa maybe reduced by kava kava.

Pregnancy and Breast-Feeding

Avoid use in pregnant or breast-feeding women.

Summary of Studies

Vote & Kieser (1997). This double-blind, 25-week trial included 101 men and women who were diagnosed with at least one of five anxiety disorders. Standardized kava kava extract (WS 1490) was compared to placebo. Results: The long-term efficacy of kava kava was superior to that of placebo. Two patients reported stomach upset.

Woelk et al. (1993). This double-blind, 6-week comparative study included 164 patients with nonpsychotic anxiety. They took kava kava extract 210 mg, oxazepam 15 mg, or bromezepam 9 mg. Results: Kava kava did as well in reducing anxiety as the two benzodiazepine-type anx-iolytic drugs.

De Leo et al. (2000). In a randomized controlled trial, 40 menopausal women were given hormone replacement therapy (HRT) and kava kava or HRT and placebo. Significant reductions in anxiety were noted at 3 and 6 months in the HRT and kava kava group.

Pittler and Ernst (2000). In a review of the literature and meta-analysis, studies concluded that kava kava extract was superior to placebo in treating the symptoms of anxiety.

Warnings

• Side effects are rare. They include liver damage, yellowing of the skin with chronic abuse, and depression of the nervous system.

• This herb should not be used by persons with certain types of depression. Discuss this with your health-care practitioner.

• Don’t drive or operate heavy machinery when taking kava kava. In one reported case, a man who drank more than 8 cups of kava kava was charged with driving under the influence.

• Don’t give kava kava to children under age 18.

• Don’t take kava kava with alcohol or other central nervous system depressants, alprazolam, or levodopa (medication for Parkinson’s disease).

• Don’t take kava kava if you are pregnant or breast-feeding.