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Herbal Medicine                                            
REF:  http://www.intelihealth.com/IH/ihtIH/WSIHW000/8513/31402.html    

Be aware that the U.S. Food and Drug Administration does not strictly regulate herbs and dietary supplements. There is no guarantee of strength, purity or safety of products containing or claiming to contain kava. Decisions to use herbs or supplements should be carefully considered. Individuals using prescription drugs should discuss taking herbs or supplements with a pharmacist or health care professional before starting.

• Unproven Uses
• Potential Dangers
• Interactions
• Dosing
• Summary
• Resources
  

Evidence    

Scientists have studied kava for the following health problem:

Anxiety

Multiple studies suggest that kava lessens anxiety. However, there are numerous reports of serious side effects or death following the use of kava, and the herb has been banned in many countries and removed from stores. It is not clear if these side effects occur only with high doses, with long-term use or in people with pre-existing liver damage. Until better safety information is available, kava cannot be recommended unless it is used under the strict supervision of a qualified health care professional. Natural Standard has collaborated with the World Health Organization (WHO) to prepare a detailed report of kava and associated adverse effects.

Stress

Early study results suggest that kava and valerian may be beneficial to health by reducing physiological reactivity during stressful situations and stress-induced insomnia. Further research is needed to confirm these results.

Parkinson's disease

Kava has been shown to increases "off" periods in Parkinson patients taking levodopa and can cause a semicomatose state when given with alprazolam. Therefore, it is not recommended.

Unproven Uses    

Kava has been suggested for many other uses, based on tradition or on scientific theories. However, these uses have not been thoroughly studied in humans, and there is limited scientific evidence about safety or effectiveness. Some of these suggested uses are for conditions that are potentially very serious and even life-threatening. You should consult with a health care professional before taking kava for any unproven use.

Anorexia Anticraving agent (addiction) Antifungal Antipsychotic Antispasmodic Aphrodisiac Arthritis Asthma Birth control Bust enhancement Cancer Colds Depression Diuretic Dizziness Gonorrhea Hemorrhoids Incontinence Indigestion Inflammation of the ear Inflammation of the uterus Jet lag

Kidney stones Leprosy Menopause Menstrual problems Migraine headache Muscle relaxant Neuroprotective Pain Parasite infections Premenstrual syndrome Premenstrual dysphoric disorder Protection of brain tissue against ischemic damage Respiratory tract infections Seizures Stroke Syphilis Toothache Urinary tract problems Vaginal prolapse Vaginitis Weight loss Wound healing

Potential Dangers    

Side Effects

• Until recently, kava was thought to be safe when used at recommended doses for up to two months. However, there are now numerous reports of severe liver problems or death in people using kava. It is not clear if these reactions have occurred at recommended doses; the U.S. Food and Drug Administration has issued warnings about 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 decision. Therefore, kava should be used only under the supervision of a qualified health care professional, and it should never be used above recommended doses.
• Other side effects may include upset stomach, allergic rash, psychotic syndromes, severe involuntary muscle movements (choreoathetosis), seizures, headache and drowsiness. In addition to liver problems, high doses of kava may cause skin changes, nervous system damage and lung damage. People with liver disease, Parkinson's disease, lung disease, depression or bipolar disease should avoid kava. Because kava may cause drowsiness, people using kava should not drive or operate heavy equipment. Kava has been reported to lower the amount of white blood cells (lymphocytes) in the body. Therefore, people using kava may be more prone to infections. An association between pneumonia and kava has been reported.
• Kava may cause sedation and affect electroconvulsive therapy outcome. Meningismus, acute urinary retention, skin lesions, mood elevation, enhanced or decreased cognitive performance, anorexia, sleeplessness, palpitations, paresthesia, headache, vomiting, and dangerously high blood pressure have been associated with kava use.

Pregnancy And Breast-Feeding

• Kava should be avoided during pregnancy because it may affect muscles in the uterus. Chemicals in kava may pass into breast milk with unknown effects, and therefore kava should be avoided during breast-feeding.

Interactions    

Interactions with drugs, supplements and other herbs have not been thoroughly studied. The interactions listed below have been reported in scientific publications. If you are taking prescription drugs, speak with a health care professional or pharmacist before using herbs or dietary supplements.

Interactions With Drugs

• Because of reports of liver damage, kava should be avoided in people taking other drugs that can damage the liver. Kava may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines, such as lorazepam (Ativan); barbiturates, such as phenobarbital; narcotics, such as codeine; and alcohol. Kava may increase the side effects of drugs that affect the chemical dopamine, such as haloperidol (Haldol), risperdone (Risperdal) and metoclopramide (Reglan). It may also add to the effects of monoamine oxidase inhibitors, including phenelzine (Nardil) and tranylcypromine (Parnate). Kava may lengthen the effects of anesthesia and should be stopped two to three weeks before some surgeries. Caution should be used when kava is taken with acetaminophen (Tylenol), because liver and kidney damage may occur. Because kava has diuretic properties, it should not be taken with diuretic drugs such as acetazolamide, amiloride, or furosemide or with angiotensin-converting enzyme (ACE) inhibitors such as benazepril, captopril, lisinopril, quinapril, or ramipril. Avoid in Parkinson’s disease or in patients with a history of medication-induced extrapyramidal effects, because kava may cause additive effects.
• Kava may cause excessive drowsiness when taken with selective serotonin reuptake inhibitors such as fluoxetine, fluvoxamine, paroxetine, or sertraline. Buspirone and opipramol may have additive effects when taken with kava.

Interactions With Herbs And Dietary Supplements

Kava may increase the amount of drowsiness caused by some herbs or supplements, such as valerian. Caution is advised while driving or operating machinery. In theory, kava may add to the effects of herbs and supplements that act like monoamine oxidase inhibitor drugs, such as evening primrose oil.

Dosing    

Adults (Aged 18 Or Older)

• Kava extract: A dose of 50 to 100 milligrams taken by mouth has been used for up to two months. Please read the above safety information.

Children (Younger Than 18):  Kava should not be given to children because safety and effectiveness are not known.

Summary    

Multiple studies suggest that kava lessens anxiety. Scientific evidence does not support the use of kava for any other conditions. There have been recent reports of serious liver damage or death in people using kava. It is not clear if these problems occurred at high doses or after long-term use. Therefore, kava should be used only under the supervision of a qualified health care professional. Kava should never be taken at doses higher than recommended or for longer than two months. Kava should be avoided in people with liver disease, Parkinson's disease or lung disease; in pregnant or breast-feeding women; and in children. It should not be used in people taking monoamine oxidase inhibitors or drugs that may damage the liver or cause drowsiness. Consult a health care professioal immediately if you have side effects.

The information in this monograph was prepared by the professional staff at Natural Standard, based on thorough systematic review of scientific evidence. The material was reviewed by the Faculty of the Harvard Medical School with final editing approved by Natural Standard.

Resources   

Selected Scientific Studies: Kava
Natural Standard reviewed more than 425 articles to prepare the professional monograph from which this version was created.

Some of the more recent studies are listed below:

Last updated July 13, 2005