Black cohosh adverse effects

A number of non-hormonal therapies have been studied for symptomatic management of vasomotor symptoms, including antidepressants [e.g., selective serotonin reuptake inhibitors (SSRIs) and venlafaxine], herbal products (e.g., soy, black cohosh, and dong quai), and a group of miscellaneous agents (e.g., gabapentin, clonidine, and megestrol). The choice of therapy depends on the patient s concomitant disease states, such as depression and hypertension, and the risk for potential adverse effects. 

Black cohosh has been one of the most studied herbal remedies for vasomotor symptoms, and it has not demonstrated a substantial benefit over placebo. The mechanism of action, safety profile, drug-drug interactions, and adverse effects of black cohosh remain unknown. In non-placebo-controlled trials conducted for 6 months or less, black cohosh demonstrated a small reduction in vasomotor symptoms. It has not been shown to be effective for vasomotor symptoms in women with breast cancer.33 There have been case reports of hepatotoxicity with the use of black cohosh.36 Caution should be exercised when considering the use of this product, especially in patients with liver dysfunction. 

Human clinical trials have indicated a lack of estrogenic effects of black cohosh. In a clinical trial of 400 postmenopausal women, administration of 40 mg of black cohosh extract daily for 1 year did not produce any endometrial hyperplasia or other adverse endometrial outcomes, and no change in endometrial thickness was observed (Raus et al. 2006). Likewise, in a clinical trial of peri- and postmenopausal women, 24 weeks of black cohosh (39 or 127 mg/ day) administration did not produce any changes in vaginal cytology and no systemic estrogenic effects were observed (Liske et al. 2002). 

A critical review on cliiucal studies of black cohosh in the treatment of menopausal symptoms concluded that specific extracts of the rhizome are safe alternatives to estrogen therapy. In trials of black cohosh preparations involving over 2800 patients, the incidence of adverse effects was 5.4% the majority (97%) were minor and none attributed to black cohosh were serious. An isopropanolic extract failed to increase estrogen-dependent mammary tumors in rats and in a rat model... 

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