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February 2000
Volume 64 |
Number 2
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| Herbal Medicines:
What Do We Need to Know? |
Jessie A. Leak, M.D.
Committee on Communications
| 2000 BC Here, eat this root. |
| 1000 AD That root is heathen.
Here, say this prayer. |
| 1850 AD That prayer is superstition.
Here, drink this potion. |
| 1940 AD That potion is snake
oil. Here, swallow this pill. |
| 1985 AD That pill is ineffective.
Here, take this antibiotic. |
|
2000 AD That antibiotic doesn't work
anymore. Here, eat this root.
|
|
-- Author Unknown --
We truly have come full circle. Humans began using plants and
plant parts for medicinal purposes over 60,000 years ago, and
our fascination with all things "natural" continues to intensify.
Perhaps it is multifactorial: disillusionment with established
medical practice and/or managed care, loss of the traditional
doctor-patient relationship, inconsistent access to medical care
or possibly the rising costs of medical care. We certainly cannot
discount the impact of slick marketing initiatives by "natural
product" companies that clearly have a captive audience.
The American public has repeatedly bought into the adage, "if
it is natural, it must be safe." Webster's dictionary defines
"natural" as "having or constituting a classification based on
features existing in nature ... the external world in its entirety."
It is a dangerous and inaccurate assumption to believe that herbal
products are necessarily safe, even if one looks only as far as
this definition. Most of us certainly would not chew on dried
or fresh foxglove leaves (digitalis purpurea) for lower abdominal
ulcers or to enhance wound healing, as the lore of folk medicine
would teach us. The cardiac glycosides (analogues of which are
still in use today) were originally isolated from this botanical.
Digoxin, however, went through the Food and Drug Administration's
(FDA) approval process, which requires randomized, double-blind,
placebo-controlled studies.
Eisenberg et. al.1 estimate that one in five U.S.
adults taking prescription medications are also using herbal medications,
megavitamins or both. These investigators found that, in 1997,
consumers spent over $10 billion out-of-pocket on these products.
Data extrapolation allowed the investigators to calculate that
approximately 15 million people in the United States who use herbal
medicinals or megavitamins in combination with prescription medications
may be at risk for adverse interactions.
These sobering data force us to raise our level of awareness
concerning possible interactions and potential effects that these
products may have on the patient (whether using prescription medications
or not) who is preparing to undergo surgery.
Overview and Historical Perspective
The oldest "prescriptions" in recorded history seem to be contained
in Babylonian clay tablets and ancient Egyptian papyrus. These
prescriptions utilized hundreds of different botanicals and foods.
From the earliest recorded times, then, plants and herbals have
been an important part of traditional healing practices. Many
cultures have a long history of herbal medicine use: the Chinese;
Ayurveda, a holistic system that originated in the Vedic civilization
of India; Curanderismo, a Mexican-American healing tradition;
and western herbalism. Many botanical compounds were the basis
of medical pharmacotherapeutics in the United States as recently
as the 1930s. The World Health Organization estimates that up
to 80 percent of the world's population still depend on herbal
medicines.
Because of the tremendous variations in culture, botanical nomenclature,
species and locale, it becomes an arduous burden at best to understand
the complexity of possible drug interactions that we might need
to be aware of in the provision of safe perioperative care. At
the very least, we should be aware of possible effects of the
most commonly sold herbs in the United States.
As of 1999, herbal medicinals still do not go through the costly
(>$230 million) FDA approval process. Plants and parts of plants
are not patent-eligible. As such, they are not defined as "drugs"
but rather as dietary supplements that undergo scrutiny similar
to commercially available foods. Therefore, the FDA can only "suggest"
but not require manufacturers of herbal products to provide reproducible,
evidence-based scientific data to the consumer. The FDA has no
control over the herbal industry in terms of safety guidelines
regulating consistency and purity of compounds, labeling accuracy,
manufacturing or the promotion of health claims for each product.
Brief Review of Side Effects
Perhaps the most devastating side effects and interactions that
anesthesiologists need to be aware of are cardiovascular instability,
prolongation of anesthesia and bleeding - particularly in conjunction
with other anticoagulants such as warfarin. Ephedra sinica (ma-huang),
an ingredient in many over-the-counter diet aids, may cause deadly
sympathomimetic effects, particularly in conjunction with heart
glycosides, guanethedine or other prescription medications. Multiple
deaths, primarily as a result of strokes and myocardial infarctions,
have been attributed to these products.
Panax ginseng (ginseng) may cause tachycardia or hypertension,
particularly in combination with other cardiac stimulant drugs.
In addition, this herbal may also decrease the effectiveness of
warfarin (decreased international normalized ratio). Tanacetum
parthenium (feverfew), commonly used as a migraine prophylactic,
may enhance bleeding by possible inhibition of platelet activity.
Warfarin may also be potentiated by concomitant use of allium
sativum (garlic), ginkgo biloba (ginkgo) or zingiber officinale
(ginger). Valeriana officinalis (valerian), piper methysticum
(kava-kava) and possibly hypericum perforatum (St. John's wort)
may all prolong the sedative effects of anesthesia. Glycyrrhiza
glabra (licorice) or hydrastis canadensis (goldenseal) may cause
or worsen hypertension and/or edema.
Educational Initiatives
ASA is taking a leading role in educating physicians and patients
alike regarding the importance of gaining and maintaining an accurate
and thorough medication history that includes herbal medicines,
megavitamins and other supplements. Unfortunately, very few series
of studies using consistently produced active ingredients are
available to date on any of these products; much of the information
that we have is anecdotal at best.
John B. Neeld, Jr., M.D., ASA Immediate Past President, and
Michael F. Roizen, M.D., Professor and Chair of the Department
of Anesthesiology at the University of Chicago, were featured
in an ASA-produced video news release (VNR), initially released
in March 1999 in conjunction with Doctors Day. That VNR reached
an estimated 38 million viewers. The VNR featured a succinct and
timely message alerting the public to the potential risks of herbal
medicines during surgery, as well as the tremendous importance
of notifying your physician of your herbal use habits.
Two educational brochures were made available by ASA: "What
You Should Know About Your Patients' Use of Herbal Medicines"
and a patient information brochure titled "What You Should Know
About Herbal Use and Anesthesia." Both of these brochures are
available through the Publications Department at the ASA Executive
Office at (847) 825-5586. These are excellent pamphlets for physicians
and health care providers as well as for distribution to patients.
Each piece features brief side effect profiles in table form for
many of the most commonly used products. The communications booth
at the 1999 ASA Annual Meeting in Dallas, Texas, featured this
information in poster form.
Take-Home Messages
When contemplating this extremely complex subject, it is important
to remember the following:
- "Natural" does not necessarily mean safe.
- Ask your patients what they are taking.
- At this time, much of the available information is anecdotal.
More double-blind, placebo-controlled studies are needed. Since
active ingredients are not consistent from study to study, it
is difficult to extrapolate meaningful data from many of them.
- Most herbal medications are not patent-eligible and
are not regulated by the FDA.
- Patients should be encouraged to discontinue these products
two weeks prior to surgery, which is the estimated time for
the compounds to be fully metabolized.
Suggested Reading: Reference:
| 1. |
Eisenberg DM, Davis RB,
Ettner SL, et al. Trends in |
| alternative medicine use in the United
States. JAMA. |
| 1998; 280:1569-1575. |
|
- Blumenthal M, Goldberg A, Gruenwald J, et al. The German Commission
E Monographs: Therapeutic Monographs on Medicinal Plants for
Human Use. Austin, TX: American Botanical Council. 1998.
- Gruenwald J, Brendler T, Jaenicke C, scientific eds. PDR
for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics
Co. 1998.
- Leak JA. Herbal medicine: Is it an alternative or an unknown?
A brief review of popular herbals used by patients in a pain
and symptom management practice setting. Curr Rev Pain.
1999; 3:226-236.
- Miller LG. Herbal medicinals: Selected clinical considerations
focusing on known or potential drug-herb interactions. Arch
Intern Med. 1998; 158(20):2200-2211.
- O'Hara MA, Kiefer D, Farrell K, et al. A review of 12 commonly
used medicinal herbs. Arch Fam Med. 1998; 7:523-536.
Jessie A. Leak, M.D., is Associate Professor,
Department of Anesthesiology and Department of Symptom Control
and Palliative Care, M.D. Anderson Cancer Center, Houston, Texas.
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