NATURAL PRODUCTS

Echinacea

Echinacea appears to have immunostimulatory effects.   It is being promoted as a natural alternative to standard drug therapy for colds, flu, bronchitis, cough, sinusitis, and inflammation of the mouth and throat.  In people without any existing contraindications, echinacea may be used and may help with these conditions.  It should not be used for autoimmune diseases, and in fact is contraindicated in such diseases as AIDS, multiple sclerosis, tuberculosis, collagenoses, leukoses, and rheumatoid arthritis.   It also should be avoided in hemophilia and by people taking immunosuppressive drugs.

It should be noted that echinacea cannot prevent the common cold and may have a limited effect on the flu.  The only proven therapy for the flu is prevention, which can be accomplished with the annual administration of the current year’s flu vaccine during the Fall.  People with egg allergies should not have flu vaccine.  There are new prescription drugs, such as Relenza and Tamiflu, which when started within 48 hours of the first flu symptoms, can limit the duration of the flu infection.  Relenza or Tamiflu are viable alternatives to flu vaccine for people allergic to eggs.  However, Tamiflu may make the symptoms, such as nausea and vomiting worse during the symptomatic period.

Echinacea affects arachidonic acid metabolism and in animal studies has inhibited cyclooxygenase, which means it can interfere with prostaglandin synthesis.  Prostaglandins are involved with many actions in the body, but most notably they are cytoprotective and have actions in pain response and uterine contractions, and are partly responsible for the inflammatory response.  Consequently, echinacea has the potential to augment the antiinflammatory action and side effects of nonsteroidal antiinflammatory drugs (NSAIDs) like Motrin, Naprosyn, Advil, and aspirin, which are prostaglandin inhibitors.  Echinacea may not have this effect on the new COX-2 cyclooxygenase inhibitors for arthritis like Vioxx and Celebrex, but it will take clinical studies to know.  Echinacea should also be avoided in pregnancy, because prostaglandins (PGF2) are active components of uterine contraction.

People with kidney disease must exercise caution when taking any NSAID drugs, because blocking prostaglandin production and cyclooxygenase may further worsen kidney function and lead to retention of water, sodium, and potassium.  This is one reason most NSAID drugs are by prescription only and why the manfuacturer's directions and warnings on over-the-counter NSAID drugs should be followed.  Echinacea use may worsen the already compromised kidney function in such patients.  All people with kidney disease should talk with their physician, prior to using echinacea.

The reason echinacea should be avoided in the hemophilias including, hemophilia A, hemophilia B, and Von Willebrand disease is because it interferes with the production of Thromboxane A2, which is partly responsible for platelet aggregation and clotting.   Echinacea use in such people can potentially lead to an uncontrolled bleed that may require an immediate infusion of blood factors to stop.

According to one 1998 study, if echinacea is used longer than eight weeks, it can potentially cause some level of hepatotoxicity (liver toxicity), and the authors recommend that it not be used with the prescription drugs Nizoral, Cordarone, methotrexate, and anabolic steroids, because they can also have adverse effects on liver function.  In the case of Nizoral (ketoconazole), it inhibits cytochrome P450 liver enzymes, which can inhibit the metabolism of some drugs, but it also may cause a rare drug-induced hepatitis that can be fatal.

Echinacea use should be avoided whenever taking any of the above drugs or drugs related to them.  Due to potential safety concerns, you should talk with your pharmacist and/or physician prior to using Echinacea and you should mention all prescription and nonprescription drugs you are taking.

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This page was last updated on 04/29/05.