Dr. Weil's Rx: Honor Complexity
Pubdate: Wed, 19 May 2004
Source: Anderson Valley Advertiser (CA)
Copyright: 2004 Anderson Valley Advertiser
Author: Fred Gardner
Dr. Weil's Rx:
Andrew T. Weil, MD, gave a talk -"grand rounds"- at UCLA's Neuropsychiatric
Institute May 11 on the topic of medical marijuana. Weil is a best-selling
author and director of the Program in Integrative Medicine at the College
of Medicine, University of Arizona. He sees patients at a clinic in Tucson.
In the early 1960s Weil and I worked together on the Harvard Crimson. I
remember him orchestrating some audacious, well-planned practical jokes,
and taking a principled stand against a faculty member named Richard Alpert
(now Baba Ram Dass), whose employment the university was terminating.
Weil's UCLA talk drew a crowd of about 200, including medical students and
physicians who were getting Continuing Medical Education credit. The
following excerpt seems particularly apt, given the neo-prohibitionist
party line -repeated ad nauseum at the recent Souder subcommittee hearings-
about marijuana containing one or more beneficial molecules that the
pharmaceutical industry will, in due course, identify and produce for us in
a form that is "pure."
Weil said, "One of the most dramatic advantages of learning to use plants
in medicine is their relative lack of toxicity compared to isolated
derivatives of plants. This should be obvious. If you find something in
nature that has a biological effect, that affects animals, and you attempt
to concentrate that therapeutic power, you inevitably concentrate toxicity
because they're one and the same thing.
"One of the basic principles of pharmacology -and by the way, that word
comes from Greek roots meaning 'the study of poisons'- is that there is no
difference between a drug and a poison except dose. Any drug given in a
high enough dose will cause toxicity. Some poisons in low-enough dose
become useful therapeutic agents. The great advantage of plant drugs is
that they're dilute. They're diluted by inactive materials. The typical
concentration of drugs in a natural pharmaceutical is on the order of
one-half to one percent by dry weight of the plant. That's an enormous
difference from a chemical compound that's 100 percent pure
"Moreover, when you ingest a plant, generally you put it into your body in
ways that cause slow absorption into the bloodstream. In general the
pharmacological power and toxicity of drugs is more correlated with the
rate of increase in concentration than with the absolute dose. A large
dose of a drug given by a route that causes slow absorption actually
produces a more muted effect than a small dose of the drug put into the
body very directly.
"Another difference between plant drugs and isolated chemicals -and this is
not something that is talked about in medical offices-is a qualitative
difference in composition. Nature does not give us drugs as pure, single
molecules. Nature produces constellations of related molecules in plants.
There may be one compound that's present in the largest amount, and if
isolated, reproduces most of the plant's drug effects. We have gotten into
the habit of calling that dominant compound the 'active principle' of the
plant. We have been taught in medicine and in pharmacology for generations
now that it's more scientific and more useful medically to isolate that
compound and purify it and, if possible, tinker with the molecule in the
laboratory to make the effects even more powerful.
"We pay a very high price in medicine for our reliance on those purified
compounds that have very dramatic effects. That price is a completely
unacceptable level of toxicity... At the moment, deaths caused by
pharmaceutical medications ranks between the sixth and fourth leading cause
of death in US hospitals. An article in JAMA a couple of years ago
estimated that we're now seeing a hundred thousand deaths a year in US
hospitals -deaths directly caused by pharmaceutical drugs. These deaths
were not 'mistakes' -not [attributable to] the wrong drug given to the
wrong patient. This was the right drug at the right dose to the right
patient from the right physician -and 100,000 people die a year! I think
that is completely unacceptable. And it would not happen if we were using
more plant drugs in medical practice.
"There's a qualitiative difference that's very difficult to talk about in
scientific audiences but I see change beginning to come. One of the
characteristics of these compounds that occur in arrays in nature is that
they often include both agonists and antagonists so you've got a kind of
built-in ambivalence, a paradoxical effect. [An agonist is a molecule that
activates a receptor; an antagonist blocks the receptor, or otherwise
cancels the agonist's effect.]
"There are herbs in Chinese medicine that raise low blood pressure and
lower high blood pressure. That makes no sense to Western pharmacology. We
think of drugs as having unidirectional action; so how can a drug possibly
do both things?
"Coca leaf is a big medicinal plant for Andean Indians, like peppermint or
chamomile for Europeans. Its main indication is for gastro-intestinal
disorders. They say it treats both diarrhea and constipation. How can that
be? Cocaine is a stimulant, it increases gut motility, so you could see
how it would help a constipated person move their bowels; but what possibly
could it do for someone with diarrhea except make it worse? Well, if you
look at the array of alkaloids in the coca leaf, they all look similar -14
or 15 variations on a molecular theme, cocaine being the dominant
component. But the cocaine molecule is a strange molecule, closely related
structurally to drugs like scopalamine and atropine that come from jimson
weed and datura. These have the opposite effect on the gut -they paralyze
the gut. Cocaine itself has a built-in paradox. According to the way the
molecule looks, it should be a gut paralytic; in practice, it increases gut
motility and causes diarrhea.
"What happens when cocaine is taken in that whole mix of other, related
molecules that have this combined agonist/antagonist property? Which effect
"Which effect predominates may have a lot to do with which receptors (in
the body) are available for binding. When you present the body with a
complex array, you're giving it choice in how it responds. That's
fundamentally a different kind of pharmaco-therapeutics from giving a
person a purified, isolated molecule that's a shove in one direction.
"I think both those kinds of medicine have their place. But I have to tell
you, as somebody who's practiced botanical medicines for many years,
there's often great value in using these natural mixtures.
"The reason that pharmacologists and most physicians have such trouble with
this concept is that we are strongly under the spell of reductionism.
Reductionism is a useful tool. It makes life simpler. It is very difficult
to study complex substances. How do you study a plant with 50 complex
molecules, all of which might contribute to its activity? It is much
simpler to say that one of these equals the whole, and to isolate that and
study it. But you're missing out on the clinical relevance of the whole
plant, which may be very different from that of the isolated molecule..."
"In other areas of science -outside of medicine-there's a rising interest
in complexity... If you want to describe changes in weather patterns or the
shapes of clouds, you can't use simplistic, classical formulas, you have to
use new mathematical models based in complexity. The rise of complexity
theory and its success in physics, mathematics and other disciplines has
not made the slightest inroad into medicine. Pharmacology is locked into
reductionist ways of thinking, especially when it approaches natural
products. We're dealing with the most complex phenomenon that nature has
produced, the human organism. It seems to me it makes much more sense, if
you're treating a complex thing, to treat it with a complementary complex
"If there is any future of marijuana as a medicine, it lies in its isolated
components, the cannabinoids, and their synthetic derivatives." -U.S.
Institute of Medicine Report, 1999
Speaking of JAMA...
The May 5 Journal of the American Medical Association journal carried an
article entitled "Prevalence of Marijuana Use Disorders in the United
States, 1991-92 and 2201-2002" by an MD named Compton and four PhDs. Their
conclusion: "Despite the stability in the overall prevalence of marijuana
use, more adults in the United States had a marijuana use disorder in
2001-02 than in 1991-92. Increases in the prevalence of marijuana use
disorders were most notable among young black men and women and young
Hispanic men. [What a coincidence -the very groups they love to harass!]
The results of this study underscore the need to develop and implement new
prevention and intervention programs targeted at youth, particularly
Most marijuana-use disorders are characterized as "abuse," which is
supposedly milder than "dependence." Compton et al define marijuana abuse
- -relying, of course, on the Diagnostic and Statistical Manual of Mental
Disorders- as "repeated instances of use under hazardous conditions;
repeated, clinically meaningful impairment in
social/occupational/educational functioning, or legal problems related to
marijuana use." In other words, getting in trouble with the law or with
the authorities at work or school is a mental disorder! This is Science
with a capital S, my fellow Americans. Talk about reductionism out of
control... They think they can reduce the intricate workings of the human
mind to a three-digit number!
A study in the current Lancet also substantiates one of Weil's points. A
team led by Dr. John Macleod of the University of Birmingham examined data
from 48 studies in search of evidence that early cannabis use causes
psychological or social problems later in life. But no such link could be
found! Cannabis-using youth tend to leave school earlier and are more
likely to use other illicit drugs, but, as Macleod observed, "This
association could have several explanations," such as poverty,
dysfunctional family, etc. "We are not saying cannabis is harmless, we are
saying the evidence is inconclusive," MacLeod told Reuters.
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