Should we be warned about black cohosh liver toxicity?
Based on this safety review, the US Pharmacopeia may develop monographs about black cohosh (Actaea racemosa, formerly Cimicifuga racemosa).
First, the details.
- Human and animal reports were reviewed.
- Reports came from the European Medicines Agency, Health Canada, the Australian Therapeutic Goods Administration, and the US Food and Drug Administration.
- Case reports pertaining to liver damage were evaluated according to the Naranjo causality algorithm scale — more about that later.
And, the results.
- 30 reports of liver damage purported to be related to the use of black cohosh products were analyzed.
- All the reports of liver damage were considered to be possibly caused by black cohosh.
- None were rated as probable or of certain causality.
- Animal toxicology information didn’t reveal unfavorable information about black cohosh.
The bottom line?
Based on this safety review, the Dietary Supplement Information Expert Committee of the US Pharmacopoeia determined that black cohosh products should be labeled to include a cautionary statement. And the US Pharmacopeia’s Botanical Expert Committee may develop monographs for black cohosh.
Sounds good, but the results are based on the Naranjo causality algorithm scale, which was designed to evaluate single-drug adverse events. Yet, a study published a month before publication of the US Pharmacopeia’s review concluded “The Naranjo scale lacks validity and reproducibility in the attribution of causality in hepatotoxicity.”
That’s not to infer that the results are wrong, just that the tool used to make the assessment is flawed, in the view of some researchers.
7/28/08 20:38 JR