PRO: MARIJUANA USE FOR CHRONIC PAIN AND NAUSEA

Smoked Marijuana Can Bring Relief to Sufferers of Neuropathic Pain
Comparable to That of Other Painkiller Drugs, Some Studies Show.

Medical marijuana use has a history stretching back thousands of
years. In prebiblical times, the plant was used as medicinal tea in
China, a stress antidote in India and a pain-reliever for earaches,
childbirth and more throughout Asia, the Middle East and Africa.

In recent decades, medical researchers have investigated marijuana's
effects on various kinds of pain -- from damaged nerves in people
with HIV, diabetes and spinal cord injury; from cancer; and from
multiple sclerosis. Marijuana has also been hypothesized to help with
nausea induced by chemotherapy and antiretroviral therapy, and with
severe loss of appetite as seen in people with the AIDS wasting syndrome.

The weed's actions are due to the active ingredients
tetrahydrocannabinol (THC) and some 60 other cannabinoids, which
mimic the action of chemicals -- known as endogenous cannabinoids --
that exist naturally in the brain. Those cannabinoids activate
receptors in our nerves, triggering physiological responses.

A legal prescription form of THC (Marinol) exists, yet researchers
say it's far from a perfect drug. Taken orally, its absorption is
highly variable and unpredictable and often delayed, says Dr. Igor
Grant, a UC San Diego psychiatrist who directs the university's
Center for Medicinal Cannabis Research. "Smoking is a very efficient
way to deliver THC," he says.

As a result of its federally illegal status, medicinal use of
marijuana is restricted to carefully vetted clinical research studies
or to patients in states such as California that have passed laws to
allow for personal medical use. Research on the medicinal use of
marijuana relies on government-issued marijuana cigarettes, which
come in different strengths and are supplied by the National
Institute on Drug Abuse.

The UC Center for Medicinal Cannabis Research in San Diego helps
coordinate clinical studies to investigate the safety and
effectiveness of marijuana. Here's what they've found.

Neuropathic pain

Recent research suggests that marijuana can assuage this chronic-pain
syndrome in which burning sensations occur and simple touch can feel
like hurt. It is unaffected by aspirin-like drugs and fairly
resistant to stronger analgesics such as opiates.

In a 2007 study on neuropathic pain related to HIV infection, 50
patients smoked marijuana cigarettes three times a day or marijuana
cigarettes from which active ingredients had been extracted. Subjects
then rated their pain on a scale ranging from "no pain" to "worst
pain imaginable." The results, published in the journal Neurology,
showed a 34% reduction in ratings of pain in the marijuana group
compared with 17% in the placebo group over five days of treatment.

Another study in 44 patients reported in June in the Journal of Pain
found that marijuana alleviated neuropathic pain arising from a
variety of conditions, including spinal-cord injury and diabetes.
Participants smoked marijuana on a set schedule -- first two puffs,
then three puffs an hour later, then four puffs an hour after that --
from a single cigarette containing either 0%, 3.5%, or 7% THC.
Average pain ratings before smoking were 55 on a 100-point scale and
decreased by 46% in both treatment groups and by 27% in the placebo
group one hour after the last puff.

Analgesic drugs are often tested against experimentally induced pain.
Such studies have been conducted for marijuana too. In one 2007
report in the journal Anesthesiology, 15 healthy volunteers received
skin injections with capsaicin -- the chemical behind that fiery
spice in chile peppers -- and then smoked different-strength
marijuana cigarettes. The medium dose, with a 4% THC concentration,
lessened the burning pain.

These three pain studies all concluded that smoked marijuana can
bring relief to sufferers of neuropathic pain comparable to other
analgesic drugs. It is not a cure, Grant says: "It's like other pain
medicines, you have to keep taking it."

Study subjects did feel high, an effect that varied among
individuals. Marijuana also affected thinking, shown as problems with
tasks of memory and complicated reasoning after the strongest
marijuana cigarettes were used. Potentially problematic, these
effects were tolerated by subjects -- no one opted out of the study
because they couldn't think straight.

Grant says it's important to have a choice of treatments because not
everyone responds to or can tolerate the available drugs.
Antidepressants are used for neuropathic pain but cause dry mouth,
constipation and urinary problems, and must be avoided by people with
conditions such as glaucoma. Others can't take aspirin-like drugs.
"Having an alternative compound is always good," Grant says.

Multiple sclerosis

Patients with multiple sclerosis suffer muscle spasms, pain and
tremor. Anecdotal reports suggest that marijuana may be helpful, but
controlled studies are few. One, presented at an April meeting, had
51 multiple sclerosis patients smoke 0% or 4% THC marijuana
cigarettes daily for three days. Intensity of spasms was reduced by
32% and pain ratings by 50% after smoking marijuana, compared with 2%
and 22% reductions after placebo cigarettes. Five subjects withdrew,
citing side effects: feeling too high, dizzy or fatigued.

Other studies in patients with multiple sclerosis used a cannabis
extract that can be taken orally. In a 2007 European Journal of
Neurology study, nearly half of 184 patients experienced at least 30%
improvement in muscle spasms.

But a 2004 Neurology paper showed no reduction in objective measures
of arm tremor with cannabis extract, although five subjects out of 13
reported feeling improvement. This might have resulted from
mood-altering effects of the drug or from some aspect of tremor not measured.

Nausea

A 2008 review published in the European Journal of Cancer Care
analyzed 30 clinical studies using cannabinoid drugs synthesized in
the lab and concluded that they were better than standard antinausea
drugs in alleviating the nausea and vomiting that accompanies
chemotherapy. One such drug is Marinol, a THC preparation approved by
the Food and Drug Administration for precisely this purpose.

Survey studies suggest that some people with HIV smoke marijuana to
counteract nausea caused by antiretroviral therapy. Researchers at
the UC Center for Medicinal Cannabis Research have tried to study the
effect of smoked marijuana on nausea and vomiting in patients
undergoing chemotherapy but have struggled to enroll enough subjects,
Grant says.

Bruce Mirken, director of communications for the Marijuana Policy
Project -- a group that lobbies for the decriminalization of
marijuana -- says he is all for research on the chemical components
in marijuana with the goal of making more-purified and perhaps
more-targeted drugs that do not deliver a "high," but does not see
"criminalizing use of that plant by people who are ill when you are
making its main psychoactive ingredient legal in the form of a very
expensive pill."

Tom Riley, a spokesman for the White House Office of National Drug
Control Policy, says marijuana advocates are seeking a free pass.
"They want to be exempted from the regular [drug] approval process," he says.