CANNABIS AND GI DISORDERS
The effectiveness of cannabis for treating symptoms related to gastrointestinal
disorders is widely recognized. Its value as an anti-emetic and
analgesic has been proven in numerous studies and has been acknowledged
by several comprehensive, government-sponsored reviews,
including those conducted by the Institute of Medicine (IOM), the U.K.
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House of Lords Science and Technology Committee, the Australian
National Task Force on Cannabis, and others. The IOM concluded, "For
patients . . . who suffer simultaneously from severe pain, nausea, and
appetite loss, cannabinoid drugs might offer broad-spectrum relief not
found in any other single medication."12
The most common gastrointestinal disorders-Irritable Bowel Syndrome
and Inflammatory Bowel Disease-affect millions of people. The disorders
are different, but each causes a great deal of discomfort and distress
and both can be disabling. Painful cramping, chronic diarrhea or
constipation, nausea, and inflammation of the intestines are all symptoms
of these GI disorders that can be alleviated by cannabis.
Irritable Bowel Syndrome (IBS) is a common disorder of the intestines that
leads to stomach pain, gassiness, bloating, constipation, diarrhea or both.
Chronic, painful abdominal cramping is common. The cause of IBS is not
known, and there is no cure. Researchers have found that the colon muscle
of a person with IBS begins to spasm after only mild stimulation. IBS is
at least partly a disorder affecting colon motility and sensation.
Inflammatory Bowel Disease (IBD) refers to both Ulcerative Colitis and
Crohn's Disease. Ulcerative colitis causes inflammation of the lining of
the large intestine, while Crohn's disease causes inflammation of the
lining and wall of the large and/or small intestine. The causes of IBD are
not known, but there are indications that the disease has a genetic
component. The immune system changes that accompany IBD suggest
that it may be an immune disorder.
The most common symptoms of Crohn's Disease are pain in the
abdomen, diarrhea, and weight loss. There may also be rectal bleeding
and fever. The most common complications of Crohn's Disease are
blockage of the intestine and ulceration that breaks through into surrounding
tissues. Surgery is sometimes required.
The symptoms of Ulcerative Colitis include diarrhea, abdominal cramps,
and rectal bleeding. Some people may be very tired and have weight
loss, loss of appetite, abdominal pain, and loss of body fluids and nutrients.
Joint pain, liver problems, and redness and swelling of the eyes
can also occur. Hospitalization and surgery are sometimes needed.
Research on cannabis and GI disorders
Research suggests that cannabis is effective in treating the symptoms of
these GI disorders in part because it interacts with the endogenous
cannabinoid receptors in the digestive tract, which can result in calming
spasms, assuaging pain, and improving motility. Cannabis has also been
shown to have anti-inflammatory properties13-15 and recent research has
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demonstrated that cannabinoids are immune system modulators, either
enhancing or suppressing immune response.16-17
Cannabis has a long
documented history of
use in treating GI distress,
going back more
than a century in western
medicine, and far
longer in the east.
While clinical studies
on the use of cannabis
for the treatment of
gastrointestinal disorders
have been largely
limited to investigations
on nausea suppression
and appetite stimulation—two conditions for which cannabis
has been consistently shown to be highly effective18-29 —the evidence in
support of cannabis therapy for other gastrointestinal diseases and disorders
is also strong. There is now extensive anecdotal evidence from
patients with IBS, Crohn's disease and other painful GI disorders that
cannabis eases cramping and helps modulate diarrhea, constipation and
acid reflux. Recent laboratory research on the endogenous cannabinoid
system in humans has identified that there are many cannabinoid
receptors located in both the large and small intestines.30-35
Cannabis and new cannabinoid drugs are attractive for GI treatment
because they can address a number of symptoms at once with minimal
side effects. Cannabinoids alter how the gut feels, affect the signals the
brain sends back and forth to the gut and modulate the actions of the
GI tract itself.36-38
Beginning in the 1970s, a series of human clinical trials established
cannabis' ability to stimulate food intake and weight gain in healthy
volunteers. In a randomized trial, THC significantly improved appetite
and nausea in comparison with placebo. There were also trends
towards improved mood and weight gain. Unwanted effects were generally
mild or moderate in intensity. Cannabis helps combat the painful
and often debilitating cramping that accompanies many GI disorders
because cannabinoids relax contractions of the smooth muscle of the
intestines. In fact, smooth-muscle relaxant properties of cannabinoids
are so well established that preparations of guinea-pig intestine are
routinely used as an in vitro screening tool to test the potency and
function of synthetic cannabinoids.
Research on a variety of rodents has shown that endogenous cannabi-
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noids play crucial neuromodulatory roles in controlling the operation of
the gastrointestinal system, with synthetic and natural cannabinoids
acting powerfully to control gastrointestinal motility and inflammation.
Cannabinoid receptors comprise G-protein coupled receptors that are
predominantly in enteric and central neurones (CB1R) and immune cells
(CB2R). The digestive tract contains endogenous cannabinoids (anandamide
and 2-arachidonylglycerol) and cannabinoid CB1 receptors can
be found on myenteric and submucosal nerves. Activating cannabinoid
receptors has been demonstrated to inhibit gastrointestinal fluid secretion
and inflammation in animal models.39-50
In the last decade, evidence obtained from the use of selective agonists
and inverse agonists/antagonists indicates that manipulation of CB1R
can have significant results.51 Research has also shown that in the case
of intestinal inflammation, the body will increase the number of
cannabinoid receptors in the area in an attempt to regulate the inflammation
by processing more cannabinoids.52
Cannabinoids have a demonstrated ability to block spinal, peripheral
and gastrointestinal mechanisms that promote pain in IBS and related
disorders.53 Animal research also indicates that cannabinoids work well
in controlling gastroesophageal reflux disease, a condition in which
gastric acids attack the esophagus and for which commonly prescribed
medications, such as atropine, have serious adverse side effects.54-56
From this evidence, many researchers have concluded that pharmacological
modulation of the endogenous cannabinoid system provides
new treatment options for a number of gastrointestinal diseases,
including nausea and vomiting, gastric ulcers, irritable bowel syndrome,
Crohn's disease, secretory diarrhea, paralytic ileus and gastroesophageal
reflux disease.57-60 The experience of patients with these GI disorders
shows that for broad-spectrum relief, cannabis is highly effective and
frequently helps when other treatment options prove ineffective.
How Cannabis Compares to Other Treatments
The medications currently employed to fight chronic GI disorders
include many that produce serious side effects. These side effects frequently
threaten the health of the patient and require other medications
to combat them.