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Tradition

WARNING: DISCLAIMER: The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Dosing

Adults (18 years and older)

300 milligrams of kava extract daily (standardized WS 1490 preparation) taken by mouth in three divided doses has been found beneficial in human studies for anxiety. Typical doses range from 50 to 280 milligrams of kava lactones daily, as a single bedtime dose or in divided doses, using a lower dose first and increasing slowly if necessary. Doses as high as 800 milligrams daily of kava extract have been taken for short periods, but have not been studied over the long term, and safety is not clear.

Children (younger than 18 years)

There is not enough scientific evidence to recommend the use of kava in children.

Safety

DISCLAIMER: Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

Allergies

Allergic skin rashes have occasionally been reported.

Side Effects and Warnings

Until recently, kava was generally thought to be safe when used in otherwise healthy people not on any other drugs, herbs or supplements, over short periods of time (one to two months) at recommended doses. Side effects may include gastrointestinal (stomach) upset, allergic rash, or mild headache. There have been numerous reports of severe liver problems in people using kava. Multiple cases of liver toxicity, including liver failure, have been reported following use of kava in Europe. The U.S. FDA has issued warnings to consumers and physicians, and has requested that physicians report cases of liver toxicity that may be related to kava use. Although many natural medicine experts still believe that kava is safe at recommended doses, there is not enough scientific information to make a clear conclusion. Therefore, kava should be used only under the supervision of a qualified healthcare professional, should never be used above recommended doses, and should be avoided by people with liver problems or taking drugs that affect the liver.

Other serious side effects have been observed with chronic or heavy use of kava, including skin disorders, blood abnormalities, abnormal muscle movements, apathy, kidney damage, seizures, psychotic syndromes, and increased blood pressure in the lungs (pulmonary hypertension). Blood in the urine has also been reported.

Several cases of abnormal muscle movements have been reported after short-term use of kava (one to four days), including tightening, twisting, or locking of the muscles of the mouth, neck (torticollis) and eyes (oculogyric crisis). Worsening of symptoms of Parkinson's disease, and several cases of abnormal whole body movements (choreoathetosis) following high doses of kava have also been noted. Tremor, poor coordination, headache, drowsiness, and fatigue have uncommonly been reported, particularly with large doses. A case of muscle cell breakdown (rhabdomyolysis) was reported in a 29 year-old man after taking an herbal combination of ginkgo, guarana, and kava.

Sedation (drowsiness) has occasionally been reported with kava use, although there is early evidence from several small human studies that kava may not significantly cause this effect. Because this issue remains unclear, driving and operating heavy machinery is not recommend while taking kava.

Eye disturbances and eye irritation have rarely been associated with chronic or heavy kava use. Rapid heart rate, electrocardiogram (ECG) abnormalities, and shortness of breath have been reported in heavy kava users. Laboratory tests suggest that kava may increase the risk of bleeding through effects on blood platelets.

Kava may cause sedation and affect electroconvulsive therapy (ECT) outcome. It has also been associated with meningismus, urinary retention, skin lesions, mood elevation, enhanced or decreased cognitive performance, anorexia, sleeplessness, palpitations, paresthesia, headache, vomiting, and dangerously high blood pressure.

Pregnancy & Breastfeeding

Use of kava cannot be recommended during pregnancy or breastfeeding. There may be decreases in the muscle strength of the uterus with the use of kava, which may have harmful effects on pregnancy. Chemicals in kava may pass into breast milk with unknown effects, and therefore this herb should be avoided during breastfeeding.