Kava hepatotoxicity: a European view.

Kava was well tolerated and considered as devoid of major side effects only until 1998 when the first report of assumed kava hepatotoxicity appeared. Causality of hepatotoxicity for kava +/- comedicated drugs was evident after the use of predominantly ethanolic and acetonic kava extracts in Germany (n=7), Switzerland (n=2), United States (n=1), and Australia (n=1) as well as after aqueous extracts in New Caledonia (n=2). Compliance regarding the recommendation for daily kava dose and duration was ascertained in only a few patients, including 2 from Germany and Switzerland. Since 450 millions of daily doses of kava extracts equating to 15 millions of monthly doses were sold in Germany and Switzerland, hepatotoxicity by kava appeared to be rare--similar to other herbal remedies, dietary supplements, and synthetic drugs. Risk factors were found in most patients and include daily kava overdose, prolonged therapy, and comedication with up to 5 other herbal remedies, dietary supplements, and synthetic drugs. Kava hepatotoxicity was not reported until 1998, thus raising the question of inferior quality of the kava raw material at times of the kava boom later on. Insufficiently defined regulatory guidelines to produce kava extracts are of some concern. Open questions refer not only to kava cultivars, but also to analytical methods and definitions of extract media and contents. Future strategies should therefore focus on the solution of a standard methodology of ascertaining quality that can assure a high degree of reliability in conjunction with actions by regulators, physicians, manufacturers, and producers. A medical advisory is also recommended as part of the labelling.