Update on the Alleged Liver Toxicity of Kava
by Ed Smith
This article is meant to address the concerns of our readers about recent adverse
event reports (AERs) which imply than kava products may have a toxic effect
on the liver. The following will give some background and an update on this
ongoing issue.
We are still actively working with the Kava Committee of the American Herb
Products Association (AHPA) on determining what more, if anything, needs to
be done to assure the continued safe use of kava products. AHPA has suggested
adding cautionary statements to kava product labels and many companies are
doing so.
Recently AHPA commissioned Dr. Donald Waller, a pharmacologist and toxicologist,
to scientifically review and evaluate all of the kava AERs. Dr. Waller concluded
that there is "no clear evidence that the liver damage reported in the
USA and Europe was caused by the consumption of kava."
The report concludes:
".... kava when taken in appropriate doses for reasonable periods of time has no scientifically established potential for causing liver damage. However, as with any pharmacologically active agent, there is always the possibility of drug interactions, preexisting disease conditions and idiosyncratic or hypersensitivity reactions, which can exacerbate the toxicity of such an agent."AHPA has been meeting and working closely with the FDA on the safety of kava products. The FDA has evaluated the kava AERs but has not declared kava products unsafe nor taken any actions against them. At this point kava products continue to be legally sold in the USA.
It appears that the German Federal Institute for Drugs and Medical Devices (BfArM)) is on the verge of making kava a controlled drug in Germany that will be available only by prescription. However, the Commission E, a special herb expert committee commissioned by BfArM, has issued a statement that is critical of BfArM's conclusions and action. The Commission E recently issued the following statement:
"When one examines the reactions in detail, it appears that the BfArM’s classification of causality linked to kava, is, to a large extent, incomprehensible, and arbitrary. Moreover, in its evaluation of cases, the BfArM had not taken into consideration various existing pieces of information, for example those with regard to other possible causes. One extreme example may be concerning the aforementioned lethal case: in this instance, it was known to the Institute that the cause of liver failure was several years of alcohol abuse, and that kava was not involved in the genesis of the liver symptoms. The autopsy had shown that the cirrhotic process had already started long before the administration of kava began."A review by Schmidt and Narstadt of eight toxicological studies on kava extracts, as well as isolated kavalactones, showed no evidence of hepatotoxic effects.
Careful evaluation of kava AER's show that most were related to the concomitant use of prescription drugs with potential hepatotoxic (liver toxicity) effects, alcoholism, or other situations that raise doubts about the validity of the kava AERs. Also, all of the kava AERs are apparently associated with concentrated extracts of kava (30- 70% kavalactones) rather than with raw kava root, traditional kava beverages, or kava tinctures (AKA, liquid extracts).
Although the reports that associate kava and liver damage have not been substantiated the following information should be considered when taking kava products:
- A qualified healthcare professional should be consulted
before taking kava if you have or have had liver problems, frequently use
alcoholic beverages, or are taking any medication
- Stop use and see a doctor if you develop symptoms that may signal liver problems (e.g., unexplained fatigue, abdominal pain, loss of appetite, fever, vomiting, dark urine, pale stools, yellow eyes or skin).