Efficacy and safety of isopropanolic black cohosh extract for climacteric symptoms

OBJECTIVE: Several clinical studies suggest that black cobosh may be effective in climacteric complaints. However, evidence of its efficacy based on current quality standards has been limited. METHODS: This randomized, multicenter, double-blind clinical trial compared the efficacy and tolerability of the isopropanolic black cohosh extract in the treatment of climacteric complaints compared with placebo. A total of 304 patients were randon-dy allocated to receive tablets corresponding to 40 mg drug or matching placebo daily for 12 weeks. ne primary efficacy measure was the change from baseline on the Menopause Rating Scale 1; secondary measures included changes in its subscores and safety variables. RESULTS: Patient groups did not differ in baseline characteristics. The isopropanolic black cohosh extract was more effective than placebo (P <.001) depending on time from symptom onset (P =.014) and follicle-stimulating hormone level (P =.011). The effect size was 0.03 to 0.05 Menopause Rating Scale units which is similar to recent hormone replacement therapy study results (0.036 Menopause Rating Scale units) and may therefore be considered clinically relevant. Women in the early climacteric phase benefited more than in the late phase. The hot flush sub-score was the most effective measure of the isopropanolic black cohosh extract's efficacy. There were no relevant group differences in adverse events, laboratory findings, or tolerability. CONCLUSION: This isopropanolic extract of black cohosh root stock is effective in relieving climacteric symptoms, especially in early climacteric women. (Obstet Gynecol 2005;105:1074-83. (c) 2005 by The American College of Obstetricians and Gynecologists).