Black cohosh does not reduce hot flashes in women

May 15 2005

Mayo Clinic researchers, working with North Central Cancer Treatment Group (NCCTG) investigators, will present new study findings about treatments to reduce hot flashes in women. The research will be outlined during the 2005 American Society of Clinical Oncology (ASCO) Annual Meeting, May 13-17 in Orlando, Fla.

Mayo researchers will present new data showing evidence that black cohosh does not reduce hot flashes in women any better than a placebo. Used extensively in Europe for treating hot flashes, black cohosh (Cimicifuga racemosa) is an herbal remedy derived from a plant native to North America and a member of the buttercup family.

The black cohosh study findings should help patients and their physicians look for other methods that can help control the common symptoms in women during menopause.

"The findings demonstrated absolutely no improvement of symptoms when women took black cohosh compared to placebo," says surgeon Barbara Pockaj, M.D., of Mayo Clinic in Scottsdale, Ariz., the lead physician in the study. "This finding is extremely important, because we can now say to our patients that black cohosh does not work and we have to try other methods to control their symptoms."

The double-blind, randomized study involved 132 women divided into two groups. One group took black cohosh pills for one four-week period and then a placebo for one four-week period. The other group took a placebo during the first four weeks, followed by the black cohosh. Participants in the study kept a daily hot flash diary during a baseline week and during the eight-week cross over treatment period. They kept track of the daily number of hot flashes and hot flash scores (measured by assigning points to each hot flash based on severity and then adding the points for a given time period).

Mayo researchers measured patient treatment preferences after completion of both treatment periods by ascertaining which treatment period, if any, the patients preferred: 34 percent of patients preferred the black cohosh treatment, 38 percent preferred placebo and 28 percent did not prefer either treatment.

As many as three out of four women in the United States experience hot flashes during menopause. Hot flashes occur in women with varying frequency and severity, causing frequent sleep interruptions that can affect a woman's mood or overall health. Certain surgical or medical treatments for cancer can cause menopause to begin earlier and more suddenly than it would normally occur; so, many women undergoing treatment for cancer must also cope with hot flashes.

Researchers say that hot flashes appear to be triggered by changes in a woman's brain chemistry that result from decreased estrogen levels as she approaches menopause.

There are other non-estrogenic treatments for hot flashes that researchers have identified that do work. Women and their physicians should talk about what treatment options are available and what might work best with the individual patient, says Dr Pockaj. DISCLOSURE: This trial was sponsored by a grant from the National Cancer Institute and conducted by a network of researchers led by the NCCTG. Drug supply for the study was provided by Hi Health. Based at Mayo Clinic in Rochester, Minn., NCCTG is a national clinical research group sponsored by the National Cancer Institute. NCCTG is a network of more than 400 community-based cancer treatment clinics in the United States, Canada and Mexico that work with Mayo Clinic to conduct clinical studies for advancing cancer treatment.