Natural Products

Kava Kava

Piper methysticum

Efficacy

• Indications with proven efficacy:
  Anxiety, nervousness
• Indications with possible, but poorly documented efficacy - the use of this product cannot be recommended:
  Anxiety related to menopause
  Benzodiazepine withdrawal
  Insomnia
• Also used for these other indications, but with no proof of efficacy:
  Aphrodisiac
  Cancer
  Chronic urinary infections
  Cold
  Headache
  Menstrual problems
  Rheumatism
  Sexually transmitted diseases (STDs)
  Uterine inflammation
  Vaginal prolapse
  Wound healing (topical)

Security

• Risk of Drug Interactions: Moderate
• Adverse Effects: Not Frequent

What is it?

Kava is a shrub, 3 meters or taller, that grows in the Pacific islands of Micronesia, Polynesia, Indonesia and New-Guinea. While it does blossom, it cannot reproduce by itself and needs man's help to propagate. The applicable part of kava is the root, from which kavalactones are extracted. Kavalactones are thought to be responsible for kava's effects. Because the kavalactone content may vary from 3 to 20%, standardized kavalactone preparations are preferred to crude extracts. Polynesians are still using kava for its "magical" properties during ceremonies and celebrations: it apparently calms those who take it and increases their sociability.

Taking 100 to 150 mg of some varieties of kava appears to be enough to induce a deep sleep within 30 minutes. Contrary to alcohol and sedatives, kava appears to be associated with no residual effect the next morning. This makes kava a very popular natural remedy against insomnia and anxiety.

Warning

In 2004, Canada adopted new regulations that control the manufacturing, packaging, labeling and importing of natural health products. The new regulations also include an adverse reaction reporting system. Products that conform to the regulation's criteria are identified with a natural product number (NPN) or homeopathic medicine number (DIN-HM) and can be legally sold in Canada. This number indicates that the product meets specific criteria for safety and purity, not that it is effective for any indication.

Medicinal plants content varies naturally from plant to plant – just as fruits from the same package may vary in taste and texture. There is no standard to measure the active content of each plant. Thus, efficacy of natural products should be expected to vary from brand to brand as well as from bottle to bottle of the same brand.

For more information about the Natural Health Products Regulations, or to check if a product has been assessed, visit the Health Canada website at http://www.hc-sc.gc.ca/dhp-mps/prodnatur/index-eng.php.

Does it work?

There is evidence that kava can effectively treat anxiety, nervousness, and stress. It should not be used for more than three months, since long-term, high-dose use may be associated with poor health.

• Anxiety, nervousness:
  The effective dose of kava ranges from 20 to 70 mg of kavalactones, 3 times a day.
• Insomnia:
  The effective dose to induce sleep appears to range from 180 mg to 210 mg, one hour before bedtime.

There is insufficient reliable information to conclude that kava is effective in any other indication, including topical application.

Is it safe?

• Kava may cause gastrointestinal upset, headache and dizziness. A prolonged use might cause a skin reaction.
• Kava is contraindicated in pregnancy, during breast-feeding, in depressed patients, with Parkinson's disease and liver disease. Kava may affect the ability to drive.
• Concomitant use with hepatotoxic drugs might increase the risk of developing liver damage. Kava is also thought to increase the effect of central nervous system depressant agents and decrease the effect of levodopa used in Parkinson's disease. Before taking kava, check with your pharmacist to make sure that there are no interactions with your regular medication.

Clinical notes

• In light of the new data revealed by Health Canada, the use of KAVA poses an UNACCEPTABLE risk to health.

References

1. Blumethal M et al. The Complete German Commission E monographs, 1998
2. Natural Medicines Comprehensive Database, Therapeutic Research Faculty, 2007
3. Lininger S. et Al. The Natural Pharmacy, Prima Health, 1998
4. Newall C et al. Herbal Medicine, a guide for health-care professionals, 1996
5. Pierce Andrea, Practical Guide to Natural Medicines, 1999
6. Health Canada - Advisory #21 Augustt 2002
7. Passeportsanté.net. Kava. http://www.passeportsante.net
8. Rotblatt M. et Ziment I. Evidence-Based Herbal Medicine, Hanley & Belfus, 2002
9. Herbal Companion to AHFS DI, American Society of Health-System Pharmacists, 2001
10. Taylor J. CE: Phytomedicinals: Uses, precautions, and drug interactions. Drug Topics 2003;1:79