Kava (Piper methysticum)
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.
Scientists have studied kava for the following health problem:
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.
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.
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.
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.
Anticraving agent (addiction)
Inflammation of the ear
Inflammation of the uterus
Premenstrual dysphoric disorder
Protection of brain tissue against ischemic damage
Respiratory tract infections
Urinary tract problems
People with allergies to kava or kavapyrones should not take kava. Skin rashes
have been reported after taking kava for two to three weeks.
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 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 Parkinsons 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,
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
The doses listed below are based on scientific research, publications
or traditional use. Because most herbs and supplements have not been thoroughly
studied or monitored, safety and effectiveness may not be proven. Brands
may be made differently, with variable ingredients even within the same brand.
Combination products often contain small amounts of each ingredient and may
not be effective. Appropriate dosing should be discussed with a health care
professional before starting therapy; always read the recommendations on
a product's label. The dosing for unproven uses should be approached cautiously,
because scientific information is limited in these areas.
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.
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.
Standard: An organization that produces scientifically based reviews
of complementary and alternative medicine (CAM) topics
for Complementary and Alternative Medicine (NCCAM): A division of the
U.S. Department of Health & Human Services dedicated to research
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:
Almeida JC, Grimsley EW. Coma from the health food store: interaction between
kava and alprazolam. Ann Intern Med 1996;125(11):940-941.
Boerner RJ, Sommer H, Berger W, et al. Kava-kava extract LI 150 is as effective
as opipramol and buspirone in generalised anxiety disorder: an 8-week randomized,
double-blind multi-centre clinical trial in 129 out-patients. Phytomedicine
Brauer RB, Stangl M, Stewart JR, et al. Acute liver failure after administration
of herbal tranquilizer kava-kava (Piper methysticum). J Clin Psychiatry
Cagnacci A, Arangino S, Renzi A, et al. Kava-kava administration reduces
anxiety in perimenopausal women. Maturitas 2003;Feb 25, 44(2):103-109.
Cairney S, Clough AR, Maruff P, et al. Saccade and cognitive function in
chronic kava users. Neuropsychopharmacology 2003;Feb, 28(2):389-396.
Campo JV, McNabb J, Perel JM, et al. Kava-induced fulminant hepatic failure.
J Am Acad Child Adolesc Psychiatry 2002;Jun, 41(6):631-632.
Clough AR, Wang Z, Bailie RS, et al. Case-control study of the association
between kava use and pneumonia in eastern Arnhem and Aboriginal communities
(Northern Territory, Australia). Epidemiol Infect 2003;Aug, 131(1):627-635.
Clough AR, Jacups SP, Wang Z, et al. Health effects of kava use in an eastern
Arnhem Land Aboriginal community. Int Med J 2003;Aug, 33(8):336-340.
Connor KM, Davidson JR. A placebo-controlled study of kava kava in generalized
anxiety disorder. Int Clin Psychopharmacol 2002;Jul, 17(4):185-188.
Cropley M, Cave Z, Ellis J, Middleton RW. Effect of kava and valerian on
human physiological and psychological responses to mental stress assessed
under laboratory conditions. Phytother Res 2002;Feb, 16(1):23-27.
Currie BJ, Clough AR. Kava hepatotoxicity with Western herbal products: does
it occur with traditional kava use? Med J Aust 2003;May 5, 178(9):421-422.
Comment in: Med J Aust 2003;May 5, 178(9):442-423. Med J Aust 2003;May 5,
De Smet PA. Safety concerns about kava not unique. Lancet 2002;Oct 26,
360(9342):1336. Comment in: Lancet 2002;May 25, 359(9320):1865.
Dietlein G, Schroder-Bernhardi D. Doctors' prescription behaviour regarding
dosage recommendations for preparations of kava extracts. Pharmacoepidemiol
Drug Saf 2003;Jul-Aug, 12(5):417-421.
Ernst E. Safety concerns about kava. Lancet 2002;May 25, 359(9320):1865.
Comment in: Lancet 2002;Oct 26, 360(9342):1336.
Escher M, Desmeules J, Giostra E, et al. Hepatitis associated with kava,
a herbal remedy for anxiety. BMJ 2001;322(7279):139.
Estes JD, Stolpman D, Olyaei A, et al. High prevalence of potentially hepatotoxic
herbal supplement use in patients with fulminant hepatic failure. Arch Surg
Gow PJ, Connelly NJ, Hill RL, et al. Fatal fulminant hepatic failure induced
by a natural therapy containing kava. Med J Aust 2003;May 5, 178(9):442-443.
Comment in: Med J Aust 2003;May 5, 178(9):421-422.
Humberston CL, Akhtar J, Krenzelok EP. Acute hepatitis induced by kava kava.
J Toxicol Clin Toxicol 2003;41(2):109-113.
Jappe U, Franke I, Reinhold D, et al. Sebotropic drug reaction resulting
from kava-kava extract therapy: a new entity? J Am Acad Dermatol
Patra KK, Coffey CE. Implications of herbal alternative medicine for
electroconvulsive therapy. J ECT 2004;20(3):186-194.
Pittler MH, Ernst E. Efficacy of kava extract for treating anxiety: systematic
review and meta-analysis. J Clin Psychopharmacol 2000;20(1):84-89.
Russmann S, Lauterburg BH, Helbling A. Kava hepatotoxicity. Ann Intern Med
Scherer J. Kava-kava extract in anxiety disorders: an outpatient observational
study. Adv Ther 1998;15(4):261-269.
Schmidt P, Boehncke WH. Delayed-type hypersensitivity reaction to kava-kava
extract. Contact Dermatitis 2000;42(6):363-364.
Steiner GG. Kava as an anticraving agent: preliminary data. Pac Health Dialog
Stevenson C, Huntley A, Ernst E. A systematic review of the safety of kava
extract in the treatment of anxiety. Drug Saf 2002;25(4):251-261.
Sun J. Morning/evening menopausal formula relieves menopausal symptoms: a
pilot study. J Altern Complement Med 2003;9(3):403-409.
Thompson R, Ruch W, Hasenohrl RU. Enhanced cognitive performance and cheerful
mood by standardized extracts of Piper methysticum (Kava-kava). Hum
Volz HP, Kieser M. Kava-kava extract WS 1490 versus placebo in anxiety disorders:
a randomized placebo-controlled 25-week outpatient trial. Pharmacopsychiatry
Wheatley D. Stress-induced insomnia treated with kava and valerian: singly
and in combination. Hum Psychopharmacol 2001;16(4):353-356.
Last updated July 13, 2005