CHICAGO -- If a medicine is made from herbs, it must be safe. After all, herbs are "natural." That's a common misperception. Far from being harmless, many herbs can cause significant drug-drug interactions with Western medicines as well as herb-drug interactions that interfere with monitoring the individual's blood chemistry.

Since herbal medicines are readily available in the US--not only in health food stores, but also in drug stores and even grocery stores--without prescriptions, most Americans assume they are harmless. Consequently, they use herbs to self-treat a variety of conditions, and to boost their body's overall functioning. But this use of herbal medicine -- which dates back almost one thousand years before the birth of Christ -- can cause serious interactions with new-generation pharmaceuticals, in addition to skewing the results of sophisticated laboratory tests. When the two worlds collide, what, if any, effect does a mixture of herbal and western medicines have on an individual? Or on the accuracy of their blood tests?

Amitava Dasgupta, Ph.D., DABCC, Professor of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, will answer this and other questions during his presentation, "Herbal Medicines: Toxicity, Drug Interactions and Interference with Therapeutic Drug Monitoring," at the 53rd annual meeting of the American Association for Clinical Chemistry (AACC), being held July 30-August 2, 2001 in Chicago.

Background
The use of herbal medicines goes as far back as 2800 BC:

-- Since 2800 BC, the Chinese have used ginkgo biloba, prepared from the ginkgo tree, and its fruits and seeds in order to sharpen mental focus.

-- For thousands of years, ginseng (which means "essence of man") has been used by the Chinese as an emergency medicine to rescue dying patients.

-- Native Americans used saw palmetto, a dwarf palm tree that grows in the Southern part of the US, for treating genitourinary condition.

-- Native Americans also used echinacea, a member of the daisy flower family, as a blood purifier

-- St. John's wort, or "herbal prozac," the most commercially sold preparation in the US, is an extract of a shrub with bright yellow flowers that bloom from June to September. The flowers are believed to be most abundant and brightest around June 24, the day traditionally believed to be the birthday of John the Baptist; hence, the name by which the product is best known.

Regulatory Issues Governing Herbal Medicines
The U.S. Food and Drug Administration (FDA) mandates that only medicines have to be proven safe before release to market. Unfortunately, herbal products do not fall under the category of drug and as long as they are not marketed for prevention of a disease, no FDA approval is required. Herbal products are classified as a "Dietary Supplement" and are marketed pursuant to the Dietary Supplement Health and Education act of 1994.

Herbal products are regulated differently in other countries. In the United Kingdom, any product not granted a license as a medical product by the Medicines Control Agency is treated as a food and can not carry any health claim or medical advice on the label. Similarly, herbal products are sold as dietary supplement in the Netherlands. In Germany, herbal monographs called the German Commission E monographs are prepared by an interdisciplinary committee using historic information, chemical, pharmacological, clinical and toxicological studies, case reports, epidemiological data and unpublished manufacturer's data. If an herb has an approved monograph, it can be marketed.

Consumer Beware
Individuals who are interested in taking herbal preparations should consult their physician to make sure that the herb they are considering is not potentially toxic or will not cause an adverse reaction, either on its own or in combination with other pharmaceutical medications. Among the herbs that can be toxic are:

Herb - Intended use - Toxicity

Borage A source of essential fatty acids, is used for rheumatoid arthritis, hypertension Hepatotoxicity; Hepatocarcinogenics

Calamus Psychoactive, not promoted in the US Carcinogenics

Comfrey Repairing bone and muscle; prevention of kidney stone Hepatotoxicity

Chan Su Heart tonic Cardiovascular toxicity

Chaparral General cleansing tonic; blood thinner; arthritis remedy; weight loss product Hepatotoxicity; Nephrotoxicity; Carcinogenics

Ephedra Herbal weight loss Cardiovascular toxicity

Licorice Treatment of peptic ulcer Sodium and water retention, hypertension, heart failure

Herbs can not only be harmful on their own, but can also interfere with the actions of pharmaceutical medications. Among these potentially dangerous interactions are:

Herbal Product - Drug - Monitoring Comments

Chan Su Digoxin Has active components like bufalin that cross-react with Digoxin assay

Danshen Digoxin May interfere with FPIA assay for Digoxin.

Kyushin Digoxin May interfere with Digoxin assay

Siberian Ginseng Digoxin (monitoring for congestive heart failure) Can create falsely elevated Digoxin concentration. Components of Siberian ginseng may cross-react with antibodies used in Digoxin assay (for congestive heart failure)

Uzara root (diuretic) Digoxin Has an additive effect with Digoxin. It also interferes with the Digoxin assay.


Not All Herbs Are Dangerous: Chinese Herbs Show Promise for Those With HIV

Since 1987, National Cancer Institute has worked with the Chinese Academy of Sciences to study Chinese medicinal herbs with anti-HIV activity. Over 1000 Chinese traditional medicines were screened using different extraction forms. Of this number, more than 140 herbs showed HIV- inhibition activity. Among them, more than 20 herbs showed significant anti-HIV activity. Baicalin, which was isolated from scutellaria bacicalensis georgi inhibited HIV reverse transcriptase; baicalin and baicalein are active components of Chinese traditional medicine. Researchers have performed molecular modeling using these compounds and discovered additional potential for inhibiting HIV-reverse transcriptase with these ancient herbs.

INTENDED USE OF COMMON HERBAL MEDICINES BY NAME:

Herbal Medicine - Intended Use

Cat's Claw Immunostimulatn with anti-viral activity. Also used by patients with HIV/AIDS for prevention of cold, influenza

Don quai Alleviating problems associated with menstruation and menopause

Echinacea Immune stimulant used to increase resistance to cold, influenza and other infections

Feverfew Relief from migraine headaches and arthritis

Garlic To lower cholesterol and blood pressure, and prevent heart attack and stroke

Ginger Prevention of motion sickness, morning sickness and nausea

Ginkgo Biloba To sharpen mental focus on otherwise health adults and sometimes used in people with dementia. Leads to the improvement of blood flow in the brain and peripheral circulation.

Ginseng Invigorating users physically, mentally and sexually and to deal with stress.

Hawthorne Use in heart failure, hypertension and angina pectoris

Kava Relief of anxiety and stress; acts as a sedative

Pokeweed Anti-viral and anti-neoplastic.

St. John's Wort Treatment of mood disorders, particularly depression

Saw Palmetto Benign prostate hypertrophy (BPH)

Serbian Ginseng Invigorating users physically, mentally and sexually and to deal with stress.

Senna Laxative

Valerian Insomnia

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Founded in 1948, the American Association for Clinical Chemistry (AACC) is the world's most prestigious professional association for clinical laboratorians, clinical and molecular pathologists, and others in related fields. Clinical laboratorians are specialists trained in all areas of human laboratory testing, including infectious and genetic diseases, DNA and the presence of tumor markers. The primary professional commitment of clinical laboratorians is the effective understanding and use of laboratory tests in order to detect, monitor and treat human diseases.

---American Association for Clinical Chemistry

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