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Echinacea (E. angustifolia DC, E. pallida, E. purpurea)

Natural Standard® Patient Monograph, Copyright © 2007 (www.naturalstandard.com). All Rights Reserved. Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Background

Echinacea (E. angustifolia DC, E. pallida, E. purpurea)

Echinacea species are perennials which belong to the Aster family and which originate in eastern North America. Traditionally used for a range of infections and malignancies, the roots and herb (above ground parts) of echinacea species have attracted recent scientific interest due to purported "immune stimulant" properties. Oral preparations are popular in Europe and the United States for prevention and treatment of upper respiratory tract infections (URI), and Echinacea purpurea herb is believed to be the most potent echinacea species for this indication. In the U.S., sales of echinacea are believed to represent approximately 10% of the dietary supplement market.

For URI treatment, numerous human trials have found echinacea to reduce duration and severity, particularly when initiated at the earliest onset of symptoms. However, the majority of trials, largely conducted in Europe, have been small or of weak design. Negative results exist of a U.S. trial in adults, which used a whole-plant echinacea preparation containing both E. purpurea and E. angustifolia . Another clinical trial reported in July 2005 did not demonstrate any clinical benefit either. However, a 2006 meta-analysis investigating the efficacy of echinacea found that the likelihood of experiencing a clinical cold was 55% higher with placebo than with Echinacea (based on three trials). The sum of the current is conflicting and further well-designed studies are needed before a definitive conclusion can be drawn. Lack of benefit in children ages 2-11 has also been reported.

For URI prevention (prophylaxis), daily echinacea has not been shown effective in human trials.

Preliminary studies of echinacea taken by mouth for genital herpes and radiation-associated toxicity remain inconclusive. Topical E. purpurea juice has been suggested for skin and oral wound healing, and oral/injectable echinacea for vaginal Candida albicans infections, but evidence is lacking in these areas.

The German Commission E discourages use of echinacea in patients with autoimmune diseases, but this warning is based on theoretical considerations rather than human data.

Synonyms

American coneflower, black Sampson, black Susan, cock-up-hat, combflower, Echinacin®, Echinaforce®, Echinaguard®, hedgehog, igelkopf, Indian head, Kansas snake root, kegelblume, narrow-leaved purple coneflower, purple coneflower, red sunflower, rudbeckia, scurvy root, snakeroot, solhat, sun hat.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidenceGrade*
Cancer
There is no clear human evidence of the effects of echinacea on any type of cancer.
C
Immune system stimulation
Echinacea has been studied alone and in combination preparations for immune system stimulation (including in patients receiving cancer chemotherapy). It remains unclear if there are clinically significant benefits. Additional studies are needed in this area before conclusions can be drawn regarding safety or effectiveness.
C
Low white blood cell counts after X-ray treatment
Studies have reported mixed results, and it is not clear whether echinacea has benefits for this use.
C
Prevention of upper respiratory tract infections (adults and children)
Preliminary studies suggest that echinacea is not helpful for preventing the common cold in adults. A recent meta-analysis suggested that standardized extracts of echinacea were effective in the prevention of symptoms of the common cold after clinical inoculation, compared with placebo. In children, a combination of echinacea, propolis, and vitamin C has been reported to reduce the number and duration of cold episodes. However, prevention research overall has not been well designed, and additional trials are needed before a clear conclusion can be drawn.
C
Treatment of upper respiratory tract infections (adults)
Although multiple low quality studies have previously suggested that taking echinacea by mouth by adults when cold symptoms begin may reduce the length and severity of symptoms, a clinical trial reported in July 2005 did not demonstrate any clinical benefit. Recent meta-analyses are conflicting; one suggested that standardized extracts of echinacea were effective in the prevention of symptoms of the common cold after clinical inoculation, compared with placebo, whereas the other reported no such benefit. Further research is needed.
C
Genital herpes
Initial human studies suggest that echinacea is not helpful in the treatment of genital herpes.
D
Treatment of upper respiratory tract infections (children)
Initial research suggests that echinacea may not be helpful in children for alleviation of cold symptoms, possibly because parents are not able to recognize the onset of common cold symptoms soon enough to begin treatment, or because the dose of echinacea for use in children is not clear. There are fundamental differences in causes of upper respiratory tract infection symptoms in children versus adults (bacterial versus viral causes; different viruses; different sites of infection; etc). Until additional research is available, echinacea cannot be considered effective in children for this use. Furthermore, development of rash has been associated with echinacea use, and therefore the risks may outweigh the potential benefits in this population.
D

Key to grades
A Strong scientific evidence for this use
B Good scientific evidence for this use
C Unclear scientific evidence for this use
D Fair scientific evidence against this use (it may not work)
F Strong scientific evidence against this use (it likely does not work)
Grading rationale

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Abscesses, acne, attention deficit hyperactivity disorder (ADHD), bacterial infections, bee stings, boils, burn wounds, cold sores, diphtheria, dizziness, eczema, gingivitis, hemorrhoids, HIV/AIDS, malaria, menopause, migraine headache, nasal congestion/runny nose, pain, psoriasis, rheumatism, skin ulcers, snake bites, stomach upset, syphilis, tonsillitis, typhoid, urinary tract infections, whooping cough (pertussis), yeast infections.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Standardization

Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. Some manufacturers standardize echinacea extracts to 4.0 to 5.0% echinacoside, while others standardize to cichoric acid. Because the active ingredient(s) has not been identified, standardization may not predict effectiveness.

Adults (18 years and older)

Capsules (of powdered herb) : For treatment of upper respiratory tract infections, 500 to 1,000 milligrams by mouth three times daily for five to seven days has been used.

Expressed juice : 6 to 9 milliliters by mouth daily, divided into two or three doses, for five to seven days has been used.

Extract : 300 milligrams of E. purpurea extract by mouth three times daily, 300 milligrams of E. angustifolia root extract three times daily, or E. purpurea above-ground plant parts three times daily (176mg EchinaGuard® [Echinacin®] Madaus GmbH) has been found effective in the prevention and/or treatment of colds although more research is needed to confirm these results.

Tincture (1:5) : 0.75 to 1.5 milliliters, gargled then swallowed, two to five times daily for five to seven days has been used (daily dose equivalent to 900 milligrams dried echinacea root). Some herbalists prefer tinctures due to theoretical immune stimulation in the tonsils when tinctures are gargled before swallowing.

Tea : Two teaspoons of coarsely powdered herb (4 grams of echinacea) in one cup of boiling water for 10 minutes, drink daily for five to seven days, is a dose that has been used. There is early evidence that echinacea tea (equivalent of 1.275 milligrams of dried herb and root per tea bag) may reduce the symptoms of upper respiratory tract infection when 5 to 6 cups are taken on the first day and decreased by 1 cup each day for the next five days.

Applied to skin (semisolid preparation) : 15% pressed herb (non-root) juice semisolid preparation has been applied daily for wounds and skin ulcers.

Injected/through the veins : Injected echinacea is not available commercially. Severe reactions to injected echinacea have been reported, and echinacea injections are not recommended.

Children (younger than 18 years)

The dosing and safety of echinacea have not been studied thoroughly in children. Reductions of recommended adult doses by 50-67% have been used in research without significant effects in the treatment of common cold symptoms, and an association with rash development. Parents considering echinacea for their children should discuss this decision with the child's health care provider before starting therapy. Some natural medicine practitioners recommend basing children's doses based on weight. To calculate the child's dose, they take the child's weight in pounds, divide by 150, and then multiply that number by the recommended adult dose.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

People with allergies to plants in the Asteraceae or Compositae family (ragweed, chrysanthemums, marigolds, daisies) are theoretically more likely to have allergic reactions to echinacea. Multiple cases of anaphylactic shock (severe allergic reactions) and allergic rash have been reported with echinacea taken by mouth. Allergic reactions including itching, rash, wheezing, facial swelling, and anaphylaxis may occur more commonly in people with asthma or other allergies. Echinacea injections have caused severe reactions and are not recommended.

Echinacea has been associated with an increased incidence of rash in children, and therefore the risks of use may outweigh potential benefits.

Side Effects and Warnings

Few side effects from echinacea are reported when it is used at the recommended doses. Reported complaints include stomach discomfort, nausea, sore throat, rash (allergic, hives, or painful lumps called "erythema nodosum"), drowsiness, headache, dizziness, and muscle aches. Rare cases of hepatitis (liver inflammation), kidney failure, or irregular heart rate (atrial fibrillation) have been reported in people taking echinacea, although it is not clear that these were due to echinacea itself. Injected echinacea may alter blood sugar levels and cause severe reactions, and should be avoided. Echinacea has been associated with an increased incidence of rash in children, and therefore the risks of use may outweigh potential benefits. Thrombotic thrombocytopenic purpura (TTP) has also been reported.

Some natural medicine experts discourage the use of echinacea by people with conditions affecting the immune system, such as HIV/AIDS, some types of cancer, multiple sclerosis, tuberculosis, and rheumatologic diseases (such as rheumatoid arthritis or lupus). However, there are no specific studies or reports in this area, and the risks of echinacea use with these conditions are not clear. Long-term use of this herb may cause low white blood cell counts (leukopenia).

Pregnancy and Breastfeeding

At this time, echinacea cannot be recommended during pregnancy or breastfeeding. Although early studies show no effect of echinacea on pregnancy, there is not enough research in this area. Pregnant women should avoid tinctures because of the potentially high alcohol content.

Methodology

This patient information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Monograph methodology

Selected references
  1. Barak V, Birkenfeld S, Halperin T, et al. The effect of herbal remedies on the production of human inflammatory and anti-inflammatory cytokines. Isr.Med Assoc.J 2002;4(11 Suppl):919-922.
  2. Cohen HA, Varsano I, Kahan E, et al. Effectiveness of an herbal preparation containing echinacea, propolis, and vitamin C in preventing respiratory tract infections in children: a randomized, double-blind, placebo-controlled, multicenter study. Arch.Pediatr.Adolesc.Med. 2004;158(3):217-221.
  3. Gallo M, Sarkar M, Au W, et al. Pregnancy outcome following gestational exposure to echinacea: a prospective controlled study. Arch.Intern.Med. 11-13-2000;160(20):3141-3143.
  4. Gillespie EL, Coleman CI. The effect of Echinacea on upper respiratory infection symptom severity and quality of life. Conn Med. 2006 Feb;70(2):93-7.
  5. Goel V, Lovlin R, Barton R, et al. Efficacy of a standardized echinacea preparation (Echinilin) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trial. J Clin.Pharm.Ther. 2004;29(1):75-83.
  6. Henneicke-von Zepelin H, Hentschel C, Schnitker J, et al. Efficacy and safety of a fixed combination phytomedicine in the treatment of the common cold (acute viral respiratory tract infection): results of a randomised, double blind, placebo controlled, multicentre study. Curr.Med.Res Opin. 1999;15(3):214-227.
  7. Kemp DE, Franco KN. Possible leukopenia associated with long-term use of echinacea. J Am Board Fam.Pract. 2002;15(5):417-419.
  8. Koenig K, Roehr CC. Does treatment with Echinacea purpurea effectively shorten the course of upper respiratory tract infections in children? Arch Dis Child. 2006 June; 91(6):535-7.
  9. Le Tourneau M. Echinacea fails to show efficacy in treating colds in a pediatric population. Altern.Ther.Health Med. 2004;10(1):16.
  10. Lindenmuth GF, Lindenmuth EB. The efficacy of echinacea compound herbal tea preparation on the severity and duration of upper respiratory and flu symptoms: a randomized, double-blind placebo-controlled study. J Altern.Complement Med. 2000;6(4):327-334.
  11. Schoop R, Klein P, Suter A, et al. Echinacea in the prevention of induced rhinovirus colds: a meta-analysis. Clin Ther. 2006;28(2):174-183.
  12. Taylor JA, Weber W, Standish L, et al. Efficacy and safety of echinacea in treating upper respiratory tract infections in children: a randomized controlled trial. JAMA 12-3-2003;290(21):2824-2830.
  13. Turner RB, Bauer R, Woelkart K, et al. An evaluation of Echinacea angustifolia in experimental rhinovirus infections. N Engl J Med. 2005 Jul 28;353(4):341-8.
  14. Vonau B, Chard S, Mandalia S, et al. Does the extract of the plant Echinacea purpurea influence the clinical course of recurrent genital herpes? Int J STD AIDS 2001;12(3):154-158.
  15. Yale SH, Liu K. Echinacea purpurea therapy for the treatment of the common cold: a randomized, double-blind, placebo-controlled clinical trial. Arch.Intern.Med. 7-14-2004;164(11):1237-1241.

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Nov 15, 2007