Medical marijuana: The next step

A panel of experts is about to recommend to the National Institutes of
Health that smoking pot should be taken seriously as a possible way to
treat sick people.

BY ROS DAVIDSON

an eightmember panel of experts, convened by the National Institutes of
Health, is about to send an unprecedented report to NIH Director Dr. Harold
E. Varmus suggesting that the medical use of marijuana shows enough promise
to warrant more scientific study. The NIH effectively controls marijuana
research because one of its branches, the National Institute of Drug Abuse,
is the only legal source of the drug for medical experiments.

The panel was convened after voters in California and Arizona passed
initiatives in November allowing people to smoke pot legally on their
doctor's recommendation. The experts listened to scientific and personal
testimony for two days in February, and have been writing and rewriting
their formal report ever since.

In the interim, the Arizona legislature has passed a bill setting aside the
voterpassed initiative until the Food and Drug Administration gives
marijuana the goahead for medical use. Last week, federal lawenforcement
officials raided a cannabis buyers club in San Francisco. Despite convening
the panel, the Clinton administration is constantly reminding doctors that
marijuana remains illegal under federal law and they risk their licenses
and time in jail if they prescribe marijuana.

Salon talked with the chairman of the panel, Dr. William T. Beaver,
professor of pharmacology and anesthesia at Georgetown University School of
Medicine in Washington, D.C., about the panel's recommendations.

There have been some studies of the medical use of marijuana in its
synthetic form THC (tetrahyrdocannabinol). Your panel is going to
recommend further study of the benefits of smoking marijuana. In what areas
does the panel think smoking marijuana could help?

The same things for which THC has already been shown to work: nausea
associated with cancer chemotherapy, loss of appetite and wasting in AIDS
patients and other patients with wasting diseases, advanced cancer, that
kind of thing.

What's the difference between THC and smoked marijuana?

THC presumably is the major active constituent of the smoked form. But they
are different in many ways. The rate of absorption into the blood, and the
duration or presence in the blood, is different than when you take (THC)
orally. When you take it orally, only 5 or 10 percent of the dose actually
winds up in your bloodstream. When you smoke it, a higher fraction gets
into the bloodstream and gets in much quicker. It goes right into the blood
directly from the lungs, in much the same way as, say, crack cocaine.
That's why the effect comes on much more rapidly.

But aren't there dozens or hundreds of compounds in smoked marijuana?
Doesn't that complicate the whole question of scientific testing?

Exactly. There are a couple of hundred that are formed when it's smoked.
The heating and the burning generates new chemicals. You get carbon
monoxide in the smoke, although there was no carbon monoxide in the
marijuana. And, as I said, it's possible to get a more intense and higher
dose quicker by smoking. On the other hand there's a tremendous variability
in how efficient people are at extracting the drug from the smoke. If you
don't inhale you get very little.

What, like Clinton?

Yes, that thought occurred to me. If somebody's an experienced smoker they
take a very long, deep breath and they hold the smoke in their lungs for an
extended period so more of the drug has a chance to get into the
bloodstream before they exhale it. Whereas an inexperienced person may just
sort of puff away at it and it's gone. So the delivered dose of the drug to
the bloodstream can vary tremendously.

So when it comes to testing the usefulness of smoking marijuana, you're
going to have to carefully monitor how people puff it.

Yes, this is potentially one of the things that might make smoked marijuana
useful: that the person can take the drug quickly and what we call titrate
it. That means taking a certain number of puffs, then they see how they
feel; then take another few, and work their way to a point where they're
getting a medically desirable effect. Theoretically this should be
possible, but the studies would have to determine that for sure.

What about side effects?

There are a lot of undesirable features of burning marijuana. It creates
contaminants, some of which are carcinogenic. Some of them alter the
ability of the lungs to fight infection. If you're an AIDS patient, the
last thing you need is something that's going to make you even more
susceptible to getting pneumonia. A marijuana cigarette probably delivers
four times as much tar, particulate matter and garbage into the lungs as a
regular cigarette. So if you figure that somebody has to smoke several of
these daily, that's equivalent to a lot of cigarettes full of undesirable
materials.

Given these undesirable features, how will you justify recommending further
study of smoking marijuana?

There was some talk among the experts about developing a dosage form in
which the pure THC would be evaporated and volatalized without actually
burning the leaves. This would give you a much purer form of the drug
without the undesirable contaminants.

What about just eating it then? The Cannabis Cultivators Club in San
Francisco, at one point at least, used to offer to sell its patients "pot
brownies."

You'd get the same situation which you have with the THC capsules, which
are currently available in dosage form.

One argument against legalizing the smoking of marijuana is that THC can be
equally effective in certain situations.

Most of what we know about the medical benefits of marijuana is based on
THC, because that's the material that was actually used in the scientific
studies back in the 1970s and 1980s. These did show that the oral form of
the drug had some efficacy against nausea and vomiting caused by
chemotherapy, and it also had some efficacy in restoring appetite and to
some degree improving weight in AIDS patients.

So, you don't need to smoke marijuana to get relief from chemotherapy
treatment?

As far as cancer chemotherapy goes, we now have a lot more effective drugs
than we had 20 years ago, when marijuana was first being experimented with.
The issue here is, if you've got drugs that are already pretty good, is
marijuana a useful "add on"? To be eligible for approval, a drug doesn't
have to be better than the existing therapy, it just has to be effective.

Of the conditions for which marijuana might be useful, which ones have the
fewest effective drugs already available?

There are fewer therapies for appetite loss that goes with AIDS or cancer.
There are some therapies for spasticity associated, say, with MS or
spinalcord injury, but they are not as effective as, say, antinausea or
antipain drugs are. The panel heard one fellow with MS who said he would
get these painful spasms at night that would wake him up and keep him from
sleeping. Before he went to bed he would smoke a marijuana cigarette, and
he would smoke another one in the middle of the night if the spasm came back.

So it's for pain that smoking marijuana might be most useful?

That's what the panel talked about. For example, there's a kind of pain
that's very hard to treat, neuropathic pain, in which people get an injury
to the actual nervous system. It's very hard to treat with conventional
analgesics. On the other hand, there are very effective treatments for
other kinds of pain, like dysmenorrhea (menstrual cramps). The idea of
someone saying, "I want to take marijuana for dysmenorrhea," makes very
little sense. We've got good drugs for that and we've got a lot of them. On
the other hand, for neuropathic pain we don't have anything that works that
well.

If you get to the testing stage and scientific trials, which require
placebos as controls, won't it be hard to come up with a convincing placebo
marijuana cigarette?

You can get marijuana with a high THC content and with a low THC content.
The material with the low content would be essentially a placebo. The
problem is how many people will be fooled by it. People who are doing the
studies are going to have to test out different methods so it isn't obvious
to the patients what they're getting, and at what time.

Are there unrealistic expectations being expressed by marijuana supporters?

Oh yes. You have to realize that most of the drugs that we actually test on
human beings do not pan out. It's sort of like hunting for gold. Most of
the time you don't find it. But supporters would say, "Well, hey, people
are seriously ill and dying, and if it makes them feel better, why make a
big federal case out of it? Under controlled circumstances, how much harm
can it do?" And it may occasionally do some good. So if you were to study
marijuana in a number of different situations and have just one of them
come through, then you could say the whole thing was probably worth it.

On the other hand, they're going to have to factor in some of the
downsides, particularly immunological phenomena. You don't want someone
with AIDS smoking marijuana to feel a little better while decreasing their
life span because they're more likely to get a pulmonary infection. The
benefit can't just be subjective it has to outweigh the toxicity you
get. April 29, 1997

Ros Davidson is a regular contributor to Salon.