Black cohosh (Cimicifuga racemosa), a perennial plant that is native to North America, is generally used to assist in the relief of the symptoms of menopause and is available as herbal health supplements. Based on the experience reported from overseas, it has become more widely used as women seek an alternative to hormone replacement therapy. However, the efficacy and long term safety of black cohosh is not clear.1
Liver toxicities reported overseas
The Australia Therapeutics Goods Administration (TGA) recently reviewed the safety of black cohosh following reports of liver toxicities suspected to be associated with its use. As of Apr 2006, the TGA is aware of 49 cases of hepatotoxicity with black c o h o s h worldwide, including 11 Australian reports. These include cases of autoimmune hepatitis, massive and sub-massive necrosis. Serious cases have been reported to occur with use of less than a month.2 In Australia, four patients were hospitalised, including two patients who required liver transplantation.3
According to TGA's assessment, many of the reports were confounded by the use of other medications and the range of ingredients in the herbal formulation being used. However, the lack of other identifiable causal substance and exclusion of viral infection in the serious cases suggest a causal association between black cohosh and serious hepatitis.2 TGA also observed that the incidence of liver reaction is very low considering the widespread use of black cohosh. Following the safety review, the TGA has strengthened the labelling of products containing black cohosh to state that black cohosh may harm the liver in some individuals and that it should be used under the supervision of a healthcare professional.
As of 31 Mar 2005, the UK Medicines and Health Regulatory Agency (MHRA) had received 20 reports of liver reactions suspected to be associated with black cohosh. The cases ranged in severity from abnormal liver function to various forms of hepatitis. The patients generally recovered or were reported to be recovering after stopping black cohosh.4 The mechanism for hepatotoxicity with black cohosh is not known. However, an immunological response has been suggested.1,5 Due to the limited information available about the formulation and usage of black cohosh in the UK as the majority of products on the market appeared to be unlicensed herbal remedies, the agency is currently keeping the safety of black cohosh under review.
 |
Local experience
HSA has not received any local reports of hepatotoxicity associated with black cohosh. Healthcare professionals are encouraged to obtain a thorough medication history from patients presenting with hepatic dysfunction including their use of alternative medicines, including herbal and other complementary medicines, as well as alcohol and conventional medicines. Healthcare professionals are also encouraged to report suspected adverse reaction to complementary medicines to the Pharmacovigilance Unit of the HSA.
References
