CDC Discussed Medical Marijuana Posted: 01-28-08 11:50am
People have used marijuana as a medical
treatment for thousands of years. Such
uses extend even to modern America.
Marijuana was listed by the U.S.
Pharmacopeia, the organization that sets
quality standards for approved drugs in
the United States, until the 1940s, when
political pressure against marijuana's
recreational use triggered its removal.
Despite the U.S. Supreme Court's ruling
that state laws allowing medicinal use of
marijuana must bow to federal law banning
it, proponents still tout this
controversial plant's ability to treat
pain, nausea and other uncomfortable side
effects of medical treatment as well as
some disease symptoms.
Marijuana 101: The plant and its
components
Marijuana refers to the dried flowers,
leaves, stems and seeds of the Cannabis
sativa plant. These parts contain the
compounds that produce the mind-altering
effect that recreational users seek when
smoking or ingesting the plant %u2014 but
they also provide components with
potential medical benefits.
Marijuana contains at least 60 chemicals
called cannabinoids. Researchers are
evaluating how effective some of these
cannabinoids might be in controlling
symptoms of certain medical conditions.
For example:
* THC. An abbreviation for
delta-9-tetrahydrocannabinol, THC is the
main component responsible for marijuana's
mind-altering effect. It also may help
treat signs and symptoms such as nausea
and vomiting that are associated with a
number of medical conditions.
* Cannabinol and cannabidiol. These
compounds have some of the properties of
THC, but cause less psychoactive effects
%u2014 the high.
* Dronabinol (Marinol). Dronabinol
(dro-NAB-in-ol) is a man-made version of
THC available by prescription. It's used
to prevent nausea and vomiting after
cancer chemotherapy when other medicines
for these side effects don't work, and to
increase appetite in people with AIDS.
How it works
When smoked or ingested, THC and other
cannabinoids in marijuana attach to two
types of receptors on cells in your body
%u2014 like keys in a lock %u2014
affecting the cells, once attached.
CB1 is one such receptor. CB1 receptors
are found mainly in your brain, especially
in areas that control body movement,
memory and vomiting. This helps explain
why marijuana use affects balance and
coordination and impairs short-term memory
and learning, and why it can be useful in
treating nausea, pain and loss of
appetite.
The other type of receptor, CB2, is found
in small numbers elsewhere in your body,
mainly in tissue of the immune system,
such as your spleen and lymph nodes. The
function of these receptors is not well
understood. They may serve as brakes on
immune system function, which may help
explain why marijuana suppresses your
immune system.
After you smoke marijuana, its ingredients
reach their peak levels in your body
within minutes, and effects can last up to
an hour and a half. When eaten %u2014 the
plant is sometimes mixed with food %u2014
the ingredients can take several hours to
reach their peak levels in your body, and
their effects may last for hours.
The prescription drug dronabinol, which is
taken as an oral capsule, takes effect in
about 30 minutes and can continue to
stimulate appetite for more than a day.
Possible medical uses
Scientists studying marijuana's potential
medical uses have found that it may help
treat a variety of conditions.
Nausea
One of THC's medical uses best supported
by research is the treatment of nausea. It
can improve mild to moderate nausea caused
by cancer chemotherapy and help reduce
nausea and weight loss in people with
AIDS.
Younger people may find marijuana more
useful as a treatment for nausea than do
older people %u2014 who may not tolerate
its mind-altering side effects as well.
The prescription form, dronabinol, also
may produce psychological side effects
that make it inappropriate for some older
people. Doctors generally prescribe
several kinds of newer anti-nausea drugs
with fewer side effects before resorting
to dronabinol.
Glaucoma
This disease %u2014 the third-leading
cause of blindness in the United States
%u2014 is marked by increased pressure in
the eyeball, which can lead to vision
loss.
In the early 1970s, scientists discovered
that smoking marijuana reduced pressure in
the eyes. Exactly how the cannabinoids in
marijuana produce this effect isn't known.
Scientists have discovered CB1 receptors
in the eyes, which may provide clues for
future research on how marijuana affects
glaucoma.
Your doctor can prescribe other
medications to treat glaucoma, but these
can lose their effectiveness over time.
Researchers are working to develop
medications containing cannabinoids that
can be put directly on the eyes %u2014 to
avoid the mind-altering side effects and
other health consequences of smoking the
plant.
Pain
People widely used marijuana for pain
relief in the 1800s, and several studies
have found that cannabinoids have
analgesic effects. In fact, THC may work
as well in treating cancer pain as
codeine, a mild pain reliever.
Cannabinoids also appear to enhance the
effects of opiate pain medications to
provide pain relief at lower dosages.
Researchers currently are developing new
medications based on cannabis to treat
pain.
Multiple sclerosis
Research results on the effectiveness of
cannabinoids in the treatment of the
tremors, muscle spasms and pain of
multiple sclerosis (MS) %u2014 a disease
of the nervous system that can cause
muscle pain %u2014 are mixed. A 2003 study
found that cannabinoids significantly
reduced pain in people with multiple
sclerosis.
Some scientists feel that more research
may show cannabinoids useful in treating
MS. Marijuana may protect nerves from the
kind of damage that occurs during the
disease. They also suggest that animal
study results, knowledge of CB1 receptors
in the brain and users' reports of
decreased symptoms after using marijuana
support this possibility.
