Bonn, Germany—Kava kava (Piper methysticum) has come under scrutiny by the German government after the health department publicised studies on the herb's potentially hazardous effects to the liver.
In a letter to the industry, Germany's Federal Institute for Drugs and Medical Development (BfArM) has asked holders of kava drug registrations to respond to the studies' 30 possible kava-related cases of liver damage in recent years, including one death.
Pharmaceutical giant Merck KGaA responded by ordering its subsidiaries, Merck dura GmbH and Merck Selbstmedikation, to pull two kava-based products—Kytta-Kava and Kavadura 120mg—from German pharmacy shelves, despite other manufacturers' trust in the pepper plant's safety.
A Merck spokesperson says, "A possible correlation between kava and the reported adverse reactions is being scientifically investigated and cannot be excluded." Merck did, however, assert that no adverse effects have been associated with its products.
Although the German authority will not decide the herb's status until early 2002, the industry alert has already resulted in a temporary quarantine in the UK. The Netherlands is considering similar action.
"As a precautionary measure, we have asked all retailers and manufacturers to withdraw kava from sale," says Maurice Hanssen, Director of the UK-based Council for Responsible Nutrition.
Despite the withdrawal, Hanssen is optimistic the product will soon be back on the shelves, noting, "The German dosage seems incredibly high compared to other parts of the world." He says the situation is a result of unsubstantiated or inappropriate scientific evidence presented to authorities.
Although some people have tried to implicate the acetone-based extraction process used in Germany to increase kava yields, the data suggest otherwise. According to Michael McGuffin, president of the American Herbal Products Association, of the 30 cases reported to the German authorities, 10 used a kava product with an acetone extraction method, compared to 16 using an ethanol extract—the variety sold in the US.
Notably, one of the cases was an 81-year-old woman with a history of alcoholism who also had been taking kava for the last nine months of her life. A biopsy found cirrhotic scars that started years before. "We don't have conclusive cases that meaningfully show a causative effect," says McGuffin.
The US Food and Drug Administration has asked healthcare professionals to review and report cases of liver toxicity to determine if any may be kava-related.
McGuffin says the FDA request will probably generate "hundreds of responses, a huge list of anecdotes, and a lot of it will be bad. I mean bad in both ways: Some will improperly implicate kava, and all of it will generate bad publicity." He says AHPA supports stronger labeling, but not removing products from the market—unless reports come back that conclusively show kava is harmful to consumers.
Coincidentally, in December researchers at Duke University in North Carolina published a study showing that 'kava is generally well tolerated, with very few side effects at recommended doses.'