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.


Ros Davidson
April 29, 1997 11:00PM (UTC)

an eight-member 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.

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In the interim, the Arizona legislature has passed a bill setting aside the voter-passed initiative until the Food and Drug Administration gives marijuana the go-ahead for medical use. Last week, federal law-enforcement 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?

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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?

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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.

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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?

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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.

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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?

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There are fewer therapies for appetite loss that goes with AIDS or cancer. There are some therapies for spasticity associated, say, with MS or spinal-cord injury, but they are not as effective as, say, anti-nausea or anti-pain 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?

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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.

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Ros Davidson

Ros Davidson is a frequent contributor to Salon.

MORE FROM Ros Davidson

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