Supplements such as St. John’s wort, kava and
ephedra could have dangerous interactions with anesthesia or other medications.
Most Americans don’t tell their doctors what
herbal supplements they are taking. Prior to surgery, such an oversight
could be disastrous.
If you’re undergoing a surgical procedure any time soon, you undoubtedly
have a list of things you have to take care of first. At or near the top
of that list should be one crucial reminder: stop taking herbal supplements
and vitamins at least two to three weeks before the procedure.
More than a third of Americans take some kind of vitamin or herbal supplement–ginkgo
biloba, garlic, ginseng, vitamin E–but 70 percent don’t tell
their doctors. And even though these remedies may be “natural”
and derived from food, many of them can be quite potent or even dangerous,
particularly if misused.
Based on information that many popular supplements can interfere with
anesthesia and with the body’s reaction to surgery, the American
Society of Anesthesiologists issued a recommendation last year that patients
should stop taking all natural remedies at least two weeks before any
surgical procedure so the body will have plenty of time to clear these
substances from the system.
More recently, an article in the Journal of the American Medical Association
[July 11, 2001] outlined a number of potentially dangerous effects that
could occur during surgery as a result of commonly used supplements such
as echinacea, ephedra, garlic, ginkgo, ginseng, kava, St. John’s
wort and valerian. The research team from the University of Chicago also
reported actual instances of life-threatening effects such as bleeding
or changes in blood pressure.
Clotting: Yes or No?
Many individuals take supplements such as vitamin E, ginkgo biloba and
garlic to improve blood flow and prevent the blood clots that are so often
associated with heart attacks.
That can be a good preventive practice, but it’s important to be
aware of the cumulative effects of such substances. If your doctor has
prescribed warfarin or asked you to take aspirin to prevent a heart attack,
you shouldn’t start taking other anticoagulants without letting
her know. Prior to surgery, such information is vital since any clotting
abnormalities can lead to severe complications.
In a case cited by the University of Chicago research team, a patient
who had been taking garlic supplements developed spinal bleeding and required
a second operation to avoid permanent paralysis.
In another study, a 45-year-old woman scheduled for a hysterectomy mentioned
at the last minute that she had been taking ginkgo for several weeks.
After clotting studies were performed, her doctors decided to postpone
the procedure rather than risk bleeding complications.
Other substances that have an effect on clotting include alfalfa, capsicum,
celery, chamomile, Chinese herbs, fenugreek, feverfew, fish oil, ginger,
ginseng, horseradish, kava, licorice, passionflower, red clover and vitamin
Many of these contain coumarins, natural agents that oppose blood clotting
in a manner similar to warfarin (a synthetic coumarin).
BP: Up or Down?
Other supplements can affect blood pressure–either up or down. Black
cohosh celery, fenugreek, garlic, hawthorn and horseradish tend to lower
blood pressure while ephedra, goldenseal and licorice increase it. Ginseng,
ginger and St. John’s wort may produce either an up or down effect.
While the usual goal is to lower blood pressure, either an up or down
effect may be unwanted during a surgical procedure.
Most licorice candy in the United States is flavored with anise oil rather
than licorice. However, pipe and cigar smokers and persons who chew tobacco
may not realize that their tobacco is laced with enough licorice to have
a dramatic effect on blood pressure, blood sugar and fluid retention.
Hawthorn is a herbal supplement some take for its beneficial effects
on the cardiovascular system–dilating blood vessels and lowering
blood pressure. Some doctors may even recommend hawthorn for patients
with mild to moderate heart failure. During surgery, however, there is
a risk that hawthorn could interact negatively with other heart medications–making
their effect either more or less powerful than desired.
Perhaps because of its effect on stress hormones, ginseng, it is claimed,
can calm you down if you’re hyper or give you energy if you’re
sluggish. Yet there are many types of ginseng, and studies have revealed
that an alarming number of products sold as ginseng are not ginseng at
all but contain substances such as phenylbutazone, aminopyrine and mandrake
If you’re going into surgery, make sure you clear your system of
all ginseng products. Risks include hypertension, clotting problems, hypoglycemia
and rapid heart beat.
Unwanted Effects on Anesthesia
More than seven million Americans today take St. John’s wort, usually
to relieve mild depression and anxiety. Believed by some to be the herbal
Prozac, St. John’s wort has quickly become one of the most popular
supplements, but several recent studies have revealed risks associated
with its use–notably involving its effect on other medications.
If you’re taking HIV medications or anti-rejection drugs following
an organ transplant, St. John’s wort can make them significantly
less effective; if you’re taking birth control pills and St. John’s
wort, you could become pregnant. In combination with anesthetics, on the
other hand, St. John’s wort could create either an intensified or
Kava, grown in the South Pacific Islands, is commonly taken to relieve
nervous anxiety and stress. It also has a sedative action and an anesthetic
activity similar to that of cocaine and is longer lasting than benzocaine.
Doctors advise that you stop taking kava at least two weeks before surgery
or dental procedures in order to avoid potentially severe effects including
coma and Parkinsonian symptoms.
Ephedra, also known as ma huang, desert tea, natural ecstasy and natural
“fen-phen,” is one of the most controversial of herbal supplements.
Frequently taken for weight loss, it has been associated with a number
Ephedra creates amphetamine-like symptoms, and side effects include heart
attack, stroke and seizure. Surgical teams must be alert to any changes
in the vital signs of a patient who has consumed ephedra products.
In making its recommendation to clear the system of all herbal supplements
prior to surgery, the American Society of Anesthesiologists did not take
a stand either for or against supplements.
Lacking regulation by the Food and Drug Administration, however, no herbal
remedies can be taken with the assumption of either safety or efficacy.
Some have established a good record; others may be downright dangerous.
Some medical schools today are including components on herbal and natural
remedies in their curricula. But 70 percent of Americans don’t tell
their doctors what herbal supplements and vitamins they are taking. Prior
to surgery, such an oversight could be disastrous.
“Beware Supplements before Surgery,”
Physician Assistant, February, 2001.
Cindy Brumley, “Herbs and the Periooperative Patient,” AORN
Journal, November, 2000.
Paul Cerrato, “Herbs and Surgery Don’t Always Mix,”
Contemporary OB/GYN, August, 2000.
W. Marvin Davis, “Dietary Supplements: Are They Safe and Reliable?”
Drug Topics, April 16, 2001.
Tom Hollon, “NIH R.Ph.s Warn Consumers about Safety of Herbals,”
Drug Topics, November 20, 2000.
Denise M. Jones and Philip S. Weintraub, “Anesthesiologists Warn:
If You’re Taking Herbal Products, Tell Your Doctor before Surgery,”
ASA Public Education, 1999.
Michael K. Ang-Lee, M.D., Jonathan Moss, M.D. Ph.D., Chun-Su Yan, M.D.,
Ph.D., “Herbal Medicines and Perioperative Care: Review,”
JAMA, July 11, 2001.
Dorothy L. Pennachio, “Drug-Herb Interactions: How Vigilant Should
You Be?” Patient Care, October 15, 2000.