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The Honolulu Advertiser
Posted on: Sunday, October 7, 2001

Beware of herbal medicine side effects

By Amy Tousman

As herbal supplements become more popular, several adverse side effects have been reported in users who also take other medications or those users undergoing anesthesia. Dietitian Jerald Foote warned in the Journal of the American Dietetic Association, "We need to view herbal supplements as drugs. Legally, they are dietary supplements, but they are drugs as far as their action in the body." Just as you would do before taking prescription drugs, it is important to learn about potential drug reactions before taking herbal medications.

Herbs are medicines derived from plants. Sometimes, even if you take an herb for one certain reason, there can be other unintended reactions. Herbs have chemical properties just as manufactured drugs do. In fact, some prescription medications, such as the heart medication Digoxin, come from plants just as herbal medications do.

Several herbal remedies can produce potentially dangerous interactions with the commonly prescribed anticlotting medication Coumadin, also known as Warfarin. These drugs are used as blood thinners in heart patients. Products that have been documented to decrease Coumadin's effects are ginseng, St. John's wort, the coenzyme Q10 and excessive amounts of green tea. Those that increase the blood thinning effect of Coumadin are vitamin E, garlic, ginger, ginkgo biloba, papain, dong quai, devil's claw, feverfew and danshen. These products may increase bleeding in patients taking Coumadin by slowing the blood's ability to clot. Since aspirin and fish oil are also a blood thinners, they can add to these effects, especially if taken with other supplements listed above.

Some herbs interfere with the way drugs are absorbed or metabolized. Ginseng may induce resistance to diuretic drugs (which increase urination and decrease swelling). Kava, used for anxiety, may increase the action of certain antiseizure medications. St. John's wort, a popular treatment for mild to moderate depression, may interact with some antidepressant medications, chemotherapy, or HIV drugs. This herb can reduce blood levels of the HIV drug, Indinivir by more than half. As a result, the body may clear the drug before it has time to work fully; low blood levels of Indinivir can lead to drug-resistant virus. St John's wort may also affect other HIV drugs that are similarly metabolized by the body.

St. John's wort reduces the effect of the heart drug digoxin and of cyclosporin, which helps prevent organ rejection in people given transplants. It may interact with some oral contraceptives, causing bleeding between periods, and may reduce the effectiveness of oral contraceptives in preventing pregnancy.

Echinacea, used to fight colds and flu may cause inflammation of the liver if used with anabolic steroids or Methotrexate. It may antagonize immunosuppressive drugs such as those used to treat lupus and may decrease the action of corticosteroids such as Prednisone.

This is not to suggest you shouldn't use these herbs. It does suggest that it is imperative that you inform your health care providers that you are taking them and learn what you can about their interactions with medications.

Some herbal products can pose a serious health risk if taken before surgery. People often believe that a product that is "natural" is safe. This is a dangerous assumption that can put surgical patients at risk.

A report issued by the Tang Center for Herbal Medicine and Research and the Pritzker School of Medicine, both in Chicago, listed herbal supplements that are most likely to lead to complications during or after surgery. Garlic, gingko, and ginger may trigger post-operative bleeding and lead to a bleeding stroke. Ginseng may cause bleeding and low blood sugar. Ephedra can lead to heart arrythmias (irregular heartbeats). Kava and valerian can cause increased sedation from anesthesia. St. John's wort can intensify or prolong the effect of some anesthetic agents. Adverse reactions can also occur with echinacea.

If you are going to have surgery, it is important to let your doctor and the anesthesiologist know ahead of time what herbs you may be taking. The American Society of Anesthesiologists warns consumers not to take herbal preparations for two weeks prior to receiving anesthesia because of possible cardiovascular instability, prolonged anesthesia, and excessive bleeding.

When used wisely, herbal medications can add to our choices in treating certain conditions.

Amy Tousman is a registered dietitian at Straub Clinic & Hospital Inc. and a member of the Hawai'i Dietetic Association.

Hawai'i experts in traditional medicine, naturopathic medicine, diet and exercise take turns writing the Prescriptions column. Send your questions to: Prescriptions, 'Ohana Section, The Honolulu Advertiser, P.O. Box 3110, Honolulu, HI 96802; e-mail ohana@honoluluadvertiser.com; fax 535-8170. This column is not intended to provide medical advice; you should consult your doctor.