The Use of Black Cohosh to Treat Menopausal Symptoms
The Use of Black Cohosh to Treat Menopausal Symptoms
Approximately 42 million American women are menopausal, and many of those women seekherbal alternatives to hormone replacement therapy (HRT) as safe and effective therapies forsymptoms of menopause. Black cohosh (Actaea racemosa syn. Cimicifuga racemosa) is awell-studied herbal alternative to HRT. The author examines the research on black cohosh, andthe concerns relating to its use and its safety.
Numerous studies since the 1980s and through 2005, including several randomized controlledtrials testing a standardized extract of black cohosh, have reported encouraging but mixed results.
The author reports on four studies conducted in 2006. Three were trials using a standardizedextract of black cohosh versus placebo or treatment given to other groups, and one was a studyusing a combination of black cohosh and St. John's wort (Hypericum perforatum). In the firststudy, black cohosh seemed to produce beneficial effects on bone metabolism by stimulatingbone-building cells, but it had a weak effect on maturation of vaginal cells. In the second study,black cohosh had no effect on menopausal symptoms: it reduced hot flash scores by only 20% inweek 4 of the study compared with 27% in the placebo group, and the frequency of hot flasheswas also affected more in the placebo group than in the treatment group. In the HerbalAlternatives for Menopause (HALT) study, which studied five protocols, hot flash frequency andintensity did not differ between those receiving the herbal intervention and those given placebosat 3, 6, or 12 months with the following exception: at 12 months, symptom intensity wassignificantly worse in the group that received the multibotanical formula plus dietary soy versusthe placebo group. The black cohosh extract, in a higher dose than is generally used in clinicalpractice, did not relieve hot flashes.
In the fourth study, a double-blinded randomized placebo-controlled study using a combinationof black cohosh and St. John's wort, the treatment group reported significantly higher scores onthe Menopause Rating Scale and the Hamilton Depression Rating Scale than did the placebogroup.
According to the author, researchers face several obstacles, e.g., therapeutic dose. The averagerecommended dose of the standardized extract is 40-80 mg per day. The dosage used in mostclinical trials to date is 20-40 mg twice daily. "Rather than randomly picking a dose to study,dose-response studies are needed to see escalating doses and their effects all in the same study,"writes the author.
Other obstacles include the large number of products available and the recommendation by theGerman Commission E that black cohosh should be taken for only 6 months.
Much has been written about the safety of black cohosh, especially in patients with breast cancerand its adverse effects on liver function. The author cites two papers, including a review of theliterature, that "offer much reassurance" with compelling safety data regarding the use of the herband breast cancer.
The World Health Organization (WHO) Collaborating Center for International Drug Monitoringhas a database for all reported adverse reactions to pharmaceutical products and herbal products,including adverse effects from black cohosh, and this database does not show any adversereactions related to liver problems.1 The 35 adverse reactions listed as of July 2000 wereprimarily general and temporary symptoms and were not concentrated in a particular organsystem.
The author cites four case reports in Australia of hepatotoxity attributed to the herb and thenpresents an analysis of the reports by Kerry Bone, B.Sc.(Hons), Dip.Phyto., the head of researchand development at MediHerb, Palmyra, Wisconsin, and a practicing herbalist and researchchemist. Among some of the flaws of the reports are the fact that the presence of black cohosh inthe products consumed was not definitely established, the names and dosages of the productswere not specified, and no information was given about the participants' past or present medicalhistories, concurrent use of medical or recreational drugs, lifestyles, dietary intakes, and otherfactors affecting their health. The cases of noninfectious hepatitis seen in these reports couldpossibly have been idiopathic hepatitis, consistent with the demographics of idiopathic hepatitis:females aged 40-50 years. Despite this highly arguable cause and effect, Australia became thefirst country to require a warning on labels of black cohosh: "Black cohosh may harm the liver insome individuals. Use under the supervision of a healthcare professional."2
Additionally, the European Medicines Agency issued a press release in July 2006 urging patientsto stop taking black cohosh if they develop signs suggestive of liver injury.3 The HerbalMedicinal Products Committee proposed a warning on labels used in European countries statingthat black cohosh may cause liver problems, and Health Canada issued an advisory on thepossible link between the herb and liver damage.
The author reports that the U.S. National Institutes of Health in November 2004 concluded thatthere was no competent evidence to support concerns about safety with respect to the use ofblack cohosh in patients with breast cancer, that there is inadequate evidence that the herbalpreparations are causally associated with hepatotoxicity, and that there is no published scientificevidence supporting the suggestion that black cohosh may have an adverse effect on liverfunction. However, it did say that liver-enzyme levels will be monitored in all women currentlyenrolled in NIH-funded trials on black cohosh, as a precautionary measure.
The author notes that the only true contraindication is for patients with cancer who take cisplatin.An in vitro study indicated that black cohosh mildly protected mouse mammary-tumor cells fromcisplatin.
In conclusion, the author points out that standardized extracts of black cohosh continue to be oneof the most reliable herbal approaches to treating a wide array of perimenopausal andmenopausal symptoms, and it can also be used safely and effectively with hormone therapy.
"Treating menopausal women is rewarding, and black cohosh is our most well-researched andimportant botanical therapy to date," she says.
Hudson T. Women's health update: Black cohosh-concerns and controversies. AlternComplement Ther. April 2007:102-106.
1World Health Organization Collaborating Center. Adverse Reactions to Drugs: Cimicifugaracemosa, Cimicifuga racemosa Root, Cimicifuga racemosa Extract. Welwyn Garden City, UK:ECRI (formerly Emergency Care Research Institute), 2000.
2Therapeutic Goods Administration (Australia). New Labelling and Consumer Information forMedicines Containing Black Cohosh (Cimifuga racemosa). February 9, 2006. Online documentat: www.tga.gov.au/cm/blkcohosh.htm. Accessed February 13, 2007.
3European Medicines Agency (EMEA) Public Statement on Herbal Medicinal ProductsContaining Cimicifugae racemosae rhizome (Black Cohosh, Root): Serious Hepatic Reactions.Online document at: http://www.emea.eu.int/htms/human/hmpc/hmpcguide.htm (Click onEMEA/269259/06 for PDF document). Accessed February 13, 2007.
As reported in the HerbClip service, from the American Botanical Council, 6200 Manor Rd,Austin, TX 78723
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