[Efficacy and safety of Black cohosh (Actaea/Cimicifuga racemosa) in the treatment of vasomotor symptoms--review of clinical trials]

Abstract

The occurrence of vasomotor symptoms in women is directly related to deficiency of estrogen, which occurs as a result of natural or surgical menopause. Hot flushes may also be a major problem for patients with a history of breast cancer, as they may result directly from cancer treatment (oophorectomy, chemotherapy-induced ovarian failure or adjuvant tamoxifen citrate therapy). Despite the lack of reliable data regarding their efficacy and safety, in recent years the usage of herbs among menopausal women has increased dynamically all over the world. The following paper reviews professional literature about Black Cohosh (Actaea/Cimicifuga racemosa), either used alone or in combination with other medicinal herbs administered in management of vasomotor symptoms. Extracts of the rootstock of Black cohosh contain such potentially biologically active constituents as triterpene glycosides (actein, cimicifugoside, deoxyacetein), isoferulic acid and alkaloids (n-methylcytisine). The mechanism of its action remains unclear. Some authors suggest that Black Cohosh contains substances with selective estrogen receptor modulator (SERM) activity. Recent data has demonstrated that Black Cohosh may have an effect on dopaminergic and serotoninergic systems. Thirty-two papers formed the basis for this review. Open-label, noncomparative studies, as well as treatment-controlled, randomized, open trials, have proven that Black Cohosh significantly reduced frequency or severity of hot flashes. The results of randomized, placebo-controlled, double-blind clinical trials were contradictory. Adverse symptoms have been rare (5,4%), mild and reversible. Most of them included gastrointestinal upsets, rashes, headaches, dizziness and mastalgia. Nevertheless, single cases of serious adverse events, including acute hepatocellular damage, have been reported, but without a clear causality relationship.