Echinacea clinical evaluations

From the clinical evaluations reported to date, no clear recommendation can be drawn with regard to the effectiveness of Echinacea in clinical environments. However, the use of Echinacea as a treatment for colds or symptoms of colds are more strongly supported by clinical studies than using Echinacea as a prophylactic. The use of standardized extracts and dosages may be a better approach for evaluating Echinacea in clinical studies. 

In view of the multiplicity of CYPs and the many possible botanical-drug interactions, highly efficient clinical study designs using CYP probe cocktails have been explored. Following successful application to St. John s wort, other botanicals that have been evaluated in this fashion include echinacea (42), saw palmetto (43), garlic (39), peppermint oil, and ascorbyl palmitate (44). The results are summarized in Table 1. Curbicin, a botanical... 

There are several botanicals that have purported immunostimulating effects. These include Panax ginseng and Echinacea purpurea (74), which have both been used as an immune stimulant. Any potential adverse effect on the pharmacological activity of immunosuppressants has not been reported in patients or evaluated in clinical studies. Given the lack of data, it would be prudent to advise against concurrent intake of these botanicals, and closely monitor changes in efficacy in patients who self-administer these botanicals. 

Turner et al. (2005) evaluated the efficacy of Echinacea angustifolia in experimental rhinovirus infections. The results of this study indicate that extracts of E. angustifolia root, either alone or in combination, did not have clinically significant effects on the infection or on the clinical illness that results from it. Be that as it may, many believe in echinacea and used it routinely to avert the common cold. 

The National Institutes of Health conducted a double-blind, 3-year study in patients with major depression of moderate severity using St. John s wort and sertraline. This study did not support the use of St. John s wort in the treatment of major depression, but a possible role for St. John s wort in the treatment of miider forms of depression was suggested. Health care providers should alert their patients about potential drug interactions with St. John s Wort. Some other frequently used herbal supplements that have not been evaluated in large-scale clinical trials are ephedra, gingko biloba, echinacea, and ginseng. Any herbal supplement should be taken only after consultation with the physician or other health care provider. 

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