Pubdate: March 30, 1999
Source: Washington Post (DC)
Copyright: 1999 The Washington Post Company
Address: 1150 15th Street Northwest, Washington, DC 20071
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Author: Susan Okie

MARIJUANA MAY YIELD MEDICINES, PANEL SAYS

Marijuana is too dangerous to the lungs to make smoking "grass" a safe
long-term treatment for illness--but some of the active ingredients in
the weed could sprout into a whole new family of medicines.

Those are among the conclusions of a landmark report issued this month
by an expert panel on the medical uses of marijuana, a topic that has
pitted patients and pro-legalization activists against the federal
government.

Marijuana's active ingredients belong to a chemical family called the
cannabinoids. In recent years, scientists have found that these
chemicals--as well as receptors on cell surfaces that respond to
them--are found naturally in the brain, where they probably play a
role in memory, control of movement and pain perception.

Scientific knowledge of cannabinoids has exploded, far outstripping
the few well conducted medical studies of marijuana's therapeutic
effects in patients, according to the pair of scientists who headed
the panel. Together, the new laboratory findings and the clinical
results suggest that some cannabinoids could be developed into
promising drugs for pain control, the relief of nausea and vomiting
and stimulation of appetite in people who have lost weight because of
AIDS or other diseases.

Some patients currently smoke or eat marijuana to treat those
problems, a situation that has produced conflict between states that
want to legalize medical use of the drug and the federal government,
which has opposed any legalization.

"There are real clinical opportunities" to develop new drugs from
cannabinoids, said Stanley J. Watson, co-director of the Mental Health
Research Institute at the University of Michigan and co-chairman of
the panel that conducted the review for the Institute of Medicine
(IOM), an independent advisory body.

The IOM report had been eagerly awaited by both sides in the ongoing
debate over whether marijuana should be made legally available for
people with certain intractable symptoms, such as nausea caused by
chemotherapy or wasting associated with AIDS.

To the delight of many activists who have urged legalization of
medical use of the drug, the panel concluded that some of marijuana's
constituents are potentially effective therapies. Nevertheless, the
report strongly opposes the use of smoked marijuana except in
short-term scientific studies lasting less than six months, citing the
dangers posed by tar, carcinogens and other substances present in the
smoke.

"Numerous studies suggest that marijuana smoke is an important risk
factor in the development of respiratory disease" and is associated
with an increased risk of cancer, lung damage and poor pregnancy
outcomes, the report states.

It calls for the rapid development of an inhaler that could deliver
cannabinoids into the lung--from which they are quickly absorbed into
the bloodstream--thus allowing patients to obtain the desired effects
without smoking.

"While we see a future in the development of . . . cannabinoid drugs,
we see little future in smoked marijuana as a medicine," said panel
co-chairman John A. Benson, an emeritus professor of medicine at
Oregon Health Sciences University.

How might cannabinoid drugs be used? "Analgesia [pain relief] may be
the biggest market for commercial exploitation," Benson said.

Animal studies show that cannabinoids can relieve mild to moderate
pain, working about as well as codeine. Because they act upon a
different set of brain receptors than the opiates (such as morphine
and codeine), they are unlikely to have the same side effects and
might be used in combination with opiate drugs. The report calls for
additional human studies in this area, saying the few trials conducted
in humans so far are inconclusive.

For nausea and vomiting caused by chemotherapy, cannabinoids are
mildly effective, but for most patients, neither marijuana or THC (an
active ingredient of marijuana) works as well as other anti-nausea
drugs currently available, the report found. Those drugs are effective
in more than 90 percent of patients, Benson said, while THC is
effective only in about 25 percent. (THC, or dronabinol, sold under
the brand name Marinol, is approved by the Food and Drug
Administration for control of severe nausea in chemotherapy patients
who don't respond to other drugs.)

But cannabinoids might enhance control of nausea when combined with
other drugs, the panel concluded, and delivering cannabinoids by
inhaler might be an effective route for people who are already too
nauseated to swallow. It called for further research on the topic.

Although many patients with AIDS say smoking marijuana has improved
their appetite and has helped them regain weight, the first clinical
trial of marijuana in such patients--conducted by Donald Abrams of the
University of California at San Francisco--has not yet been completed.
Marinol was approved by the FDA for this purpose in 1992, but some
people with AIDS find its psychological effects too intense and say it
takes too long to act, the report said. The panel urged further
research on the use of cannabinoids in AIDS, saying they could be
helpful both as appetite stimulants and to reduce pain, nausea and
anxiety.

The panel also cited an abundance of anecdotal reports that marijuana
and THC can relieve painful muscle spasms in patients with multiple
sclerosis, but said that to date there have been no good animal
studies or well conducted clinical trials.

Marijuana has been advocated to treat a number of other conditions,
but the panel found the evidence for its benefits weak. It was not
impressed with cannabinoids' potential for treating glaucoma,
migraines or movement disorders such as Parkinson's disease or
Huntington's disease.

The report recognizes the dilemma faced by patients who have turned to
marijuana because they cannot get relief from legal medicines, and
said such patients "will find little comfort in a promise of a better
drug 10 years from now."

In some states, people using marijuana to treat diseases such as AIDS
or multiple sclerosis have been arrested. Eight states have laws
permitting doctors to prescribe marijuana, and five more passed
medical marijuana initiatives last fall. Under federal law, however,
marijuana is classified as an illegal drug with no legitimate medical
use; doctors can face prosecution for prescribing it, and patients for
possessing it. Yet, some patients with chronic illnesses insist that
marijuana has made their symptoms bearable and has even prolonged
their lives. In such cases, if there is no alternative treatment, the
panel suggested establishing a system under which marijuana could be
provided on a compassionate basis, as an experimental drug, and
patients' condition would be monitored closely.

Greg Scott, 37, a Florida man with AIDS, said that smoking marijuana
helped him gain weight and thus avoid having to be fed intravenously
through a tube that carried a high risk of infection.

"I am living proof that in some cases, smoking marijuana is a viable
and beneficial alternative," he said.
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