Echinacea

Note: This review is focused only on aspects of echinacea that may be of greatest interest to individuals with cancer. Please seek additional information sources for a more comprehensive review of echinacea as it relates to other health conditions and diseases.

Overview & Background

Echinacea is one of the most commonly used herbs in the United States today. People take echinacea for a variety of reasons. Some popular reasons for using echinacea include:

• Treatment and prevention of the common cold and other respiratory infections
• Treatment of urinary tract infections, vaginal yeast infections, genital herpes, streptococcus (strep throat), sinus infections, and other bacterial, viral, and fungal infections
• To support the immune system and improve or enhance immune function in people with cancer, chronic fatigue syndrome, and HIV/AIDS
• To treat skin infections through topical application (applied to the surface of the body, such as on the skin)

There are many other proposed uses for echinacea, but these are some of the more common reasons for which people use this herb.

Effectiveness

The Common Cold and Respiratory Tract Infections

Echinacea has been studied most extensively for treating and preventing the common cold and related respiratory tract infections. Research on this topic is mixed. Some studies suggest that echinacea may help reduce the likelihood of getting a cold and may reduce the symptoms and duration of colds in people who have them. However, other, well-designed research studies show no benefit at all from using echinacea for preventing or treating colds.

There are a number of reasons for why the research is unclear and conflicting in this area.

• There are several different species of echinacea plant and it is possible that they are not all equivalent for treating infections.
• The dosages and active ingredients in over-the-counter echinacea products are not standardized. It is difficult to know if different research studies are using equivalent products.
• Different parts of the echinacea plant may contain different active components. Herbal products that are formulated with the root may be different from products made up of the stem, the leaves, or the flower.
• The time of year and location from which echinacea is harvested may affect the active ingredients in the plant.

For all of these reasons, we cannot know with certainty whether echinacea actually is beneficial for preventing or treating the common cold. However, one of the most recent, large studies of echinacea and the common cold does provide support that this herb may reduce the number and duration of colds when used short term.

Other Uses 

The use of echinacea to treat other types of infections and to support or improve immune function in people with cancer, chronic fatigue syndrome and other serious conditions is not well-studied. There are no well-controlled trials to support the use of echinacea in these situations and no evidence of benefit. This does not mean that it is proven that echinacea will not be helpful in these circumstances. However, we simply do not have enough information to know whether echinacea will provide benefit in these cases.

Contraindications & Cautions for Echinacea

Echinacea is considered safe for general, short-term use of up to 12 weeks. Using echinacea for longer than 12 weeks at a time is not recommended, because some research suggests that long term use of more than 12 weeks duration may suppress or decrease immune function.

• Allergic reactions to echinacea are rare, but they can happen. People who have allergies to ragweed, daisies, marigolds, and related plants may be more likely to have an allergic reaction to echinacea and should avoid this herb or use with caution.
• Echinacea should not be used by anyone with hematologic (blood and lymph) cancers, including all types of leukemia, lymphoma, and myeloma, without first talking to your health care team. Some research suggests that echinacea may stimulate the growth of certain types of hematologic cancer cells.
• Echinacea should be discontinued for at least one week prior to surgery and for one week after surgery to avoid negative medication interactions.

Another concern with echinacea is the possibility that it may interact negatively with some medications. This includes medications that are used to treat cancer. Echinacea may interact negatively with any of the following cancer treatment-related medications: 

• Taxanes (Taxotere® and Taxol®)
• Cyclophosphamide (Cytoxan®)
• Irinotecan (Camptosar®) or Topotecan (Hycamptin®)
• Vinca Alkaloids (Vinblastine [Velban®], Vincristine [Oncovin®], Vindesine [Eldisine®], and Vinorelbine[Navelbine®])
• EGFR-TK (Epidermal Growth Factor Receptor Tyrosine Kinase) Inhibitors (gefitinib [IRESSA®])
• Any Immunosuppressant Medication including cyclosporine (Sandimmune®, Neoral®, Gengraf®), azathioprine (Azasan®, Imuran®), daclizumab (Zenapax®), mycophenolate (CellCept®), tacrolimus (Prograf®), basiliximab (Simulect®), sirolimus (Rapamune®), muromonab-CD3 (OKT3®, Orthoclone®), and prednisone (Prednisone Intensol®, Sterapred®, Sterapred DS®, Deltasone®, Orasone®)
• Warfarin (Coumadin®)
• Odansetron (Zofran®)

Some of these potential interactions are theoretical, which means they may occur, but are not proven to occur. For this reason, be sure to discuss your individual situation with your health care team before you use echinacea during cancer treatment. Echinacea may be safe for some individuals with cancer, but only you and your doctor, working together, can decide if echinacea is safe for you.

One additional concern with echinacea is the quality of the product. Independent researchers have confirmed that some echinacea products do not contain the ingredients as claimed on the product label. As well, some echinacea products have been found to be contaminated with lead and other heavy metals. For more information on how to chose a good quality dietary supplement, please see the American Cancer Society's information Dietary Supplements: How To Know What Is Safe.

Disclaimer

This list of contraindications is not guaranteed to be complete and is based upon currently available evidence, which is subject to change as new research emerges. There are many other medications that may interact negatively with echinacea. This list addresses medications commonly used to treat individuals with cancer and does not address all possible medication interactions. Always discuss your use of dietary supplements with your doctor. Be sure to let your doctor know about any dietary supplements or other over-the-counter medications that you currently use or plan to use during your cancer care.

References

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2. Basch E, Ulbricht C, Basch S, Dalton S, Ernst E, Foppa I, Szapary P, Tiffany N, Orlando CW, Vora M. An evidence-based systemic review Echinacea E. angustifolia DC, E. pallida, E. purpurea by the Natural Standard Research Collaboration. J Herb Pharmacother. 2005;5:57-88.
3. Consumer Lab.com. Product Review: Echinacea. Available at: http://www.consumerlab.com/. Accessed February 28, 2008.
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6. Natural Medicines Comprehensive Database. Echinacea Full Monograph. Available at: http://www.naturaldatabase.com. Accessed February 28, 2008.
7. Shah SA, Sander S, White CM, Rinaldi M, Coleman CI. Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis. Lancet Infect Dis. 2007;7:473-80.
8. Spelman K, Burns J, Nichols D, Winters N, Ottersberg S, Tenborg M. Modulation of cytokine expression by traditional medicines: a review of herbal immunomodulators. Altern Med Rev. 2006;11:128-50.
9. Zhai Z, Liu Y, Wu L, Senchina DS, Wurtele ES, Murphy PA, Kohut ML, Cunnick JE. Enhancement of innate and adaptive immune functions by multiple Echinacea species. J Med Food. 2007;10:423-34.
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Publish Date: February 2008