Health Committee on May 1st, 2014

[The Chair, Conservative, Ben Lobb]

I normally instruct members of Parliament to ask directly where they'd like their questions to be answered.

[Wladyslaw Lizon, Conservative, Mississauga East—Cooksville, ON]

Dr. Kahan.

[Dr. Meldon Kahan]

Sure. I can address that.

This is not really true and it's not been validated in studies. The studies that have been done on smoked cannabis were very small, and they compared smoked cannabis to placebo.

In the only trial we could find that compared smoked cannabis to an oral cannabinoid, called dronabinol, the dronabinol was actually superior. It caused longer pain relief than the smoked cannabis. That was the only study that we could find. There are reasons for that. The metabolism of oral cannabinoids make it last longer than smoked cannabis.

In any event, I don't believe this is at all an established fact, that smoked cannabis is more effective than oral cannabis. I think many patients and individuals who smoke cannabis confuse its psychoactive effects—its pleasant psychoactive effects of euphoria and relief of anxiety—with pain relief.

The fact is that if you are prescribing a medication for pain relief, what you absolutely do not want is to make the patient cognitively impaired and experiencing the mood-altering effects of a drug every day, all day, for years on end. Smoked cannabis is so far from any other prescription medication in terms of proof of effectiveness or safety that Health Canada would never even come close to approving it as a medication, if it weren't for this essentially political process of the new medical marijuana regulations.

Furthermore, there is no medication in the world that is delivered by a smoked delivery system, where you actually burn a plant product. That's a very primitive way of delivering a medication. It gives an uncontrolled, very high rise in THC levels and a sharp decline, and it contains numerous harmful products that are carcinogenic and cause heart disease and stroke and other problems.

I know that people say that it's so much better and it contains magic ingredients that haven't yet been identified. I think that there is a strong possibility that patients and other individuals who say that are confusing its psychoactive effects with its actual therapeutic benefit.

[Prof. Harold Kalant]

I would just like to add a very brief comment to what Dr. Kahan has said. The difference between smoking and oral use of cannabis or pure cannabinoids is that when you inhale the cannabis containing the THC it is absorbed into the blood and reaches the brain more rapidly than when it's taken by mouth. So it delivers an effect more rapidly, and if you were using the drug to relieve nausea and vomiting, for example after drug treatment for cancer or for other chronic diseases, the relief may be produced more rapidly. The blood level and the brain levels rise very rapidly when you smoke, but fall very rapidly as the drug is redistributed throughout the body. When it's taken by mouth the absorption is slower but more even and longer sustained and therefore the effect is not as intense but it is longer lasting.

As Dr. Kahan has said, for the relief of pain for example, it is a greater advantage than a sudden rapid onset, whereas for relief of vomiting, something can be said in favour of administering it by the more rapid route, but again its duration is less.

[Wladyslaw Lizon, Conservative, Mississauga East—Cooksville, ON]

The second question I have is about people who use marijuana to treat certain medical conditions. Are other treatments available to treat those conditions or do they have to use marijuana?

[Prof. Harold Kalant]

You raise a very good point. All the current uses that have been tested—not all have been approved—for which some evidence exists of a beneficial effect of cannabis, it is not the most effective, the most potent, or the most reliable drug. However, some patients don't respond even to the best drugs, and for those patients cannabis can be a useful fallback.

A number of studies show if you combine cannabis with the other drugs, the more effective ones, you can get a better effect with less risk of side effects by using a smaller dose of each in combination, than a full dose of either one alone. That has been shown for relief of pain by the administration of an opiate drug together with cannabis in lower doses. It has been shown, in one study at least, with epilepsy where the conventional anti-epileptic drugs were combined with cannabidiol, CBD, to give a better control of the seizures than had been obtained with the conventional drugs alone. The possibility of combined use needs to be further investigated.

[The Chair, Conservative, Ben Lobb]

Okay, your time is up, Mr. Lizon.

Ms. Fry, you're up.

[Hedy Fry, Liberal, Vancouver Centre, BC]

Thank you very much, Mr. Chair.

I want to thank you both for at least giving some of the benefits as well as the risks, which is how I always look at it when you evaluate any kind of drug at all. As you said quite eloquently, Dr. Kalant, obviously nothing that is of benefit is without risk. We all know that if you take enough Aspirins, you're going to bleed to death with a stomach ulcer if you've taken a bottle of them. I think we know that.

I wanted to talk somewhat about a report from the CMAJ that called for the decriminalization of marijuana, because they said—and I'm quoting from them—that they think the problem that people talked about in terms of lung cancer, and I agree.... I think there are large amounts of tar and benzopyrenes in cannabis, but as the medical association and the medical journal said, you don't smoke a pack of marijuana cigarettes a day, as you tend to do with tobacco, so some of that effect in terms of lung cancer may be mitigated because of the small amounts that people may smoke. I wanted to ask you about that.

There's a second thing I wanted to ask you about. Obviously, I think we have known all along that the long-term effects of cognitive problems coming from the smoking of marijuana over long periods amongst young people, under about 40, are high and that we in fact...the incidents of young people, of parents, who are smoking. But I think one needs to counterbalance that with the dangers of alcohol in a pregnant mother, which creates not only physical but severe mental and cognitive problems.

I think while we agree that marijuana has harms—I don't think anyone is suggesting that it doesn't—here's what I think I would like to hear from you. Do you think that if one decriminalizes, as the Canadian Medical Association Journal suggested, what you would do is at least rid us of some of the social and legal harms? It is my understanding that 600,000 Canadians have criminal records for the possession of cannabis, and that leads to some harm. It leads to social and legal harm when you have young people trying to get in the army and some people trying to get into university fined. I know that in the United States it's three strikes and you're out. You can never get into university if you've been caught with cannabis three times.

I want you to talk a little bit.... I know that you talk about the psychoactive effects, etc., and the neurological effects. I wondered if you have anything to comment on in regard to this as we look at it in comparison with tobacco and alcohol.

[Prof. Harold Kalant]

Well, certainly I agree with the view that giving criminal records—especially to young people whose lives are all ahead of them—for possession of small amounts for personal use is not a benefit to society. On the other hand, legalization is not the same thing as decriminalization. Decriminalization means that the use is still disapproved but that the measures applied to prevent excessive use, or to prevent its use at all by particularly vulnerable individuals, are by means other than criminal sanctions and criminal records.

Legalization, on the other hand, means the removal of all restraints and that—

[Hedy Fry, Liberal, Vancouver Centre, BC]

What if you regulate it the way you do alcohol and tobacco?

[Prof. Harold Kalant]

Well, I would use alcohol as an example of how unsatisfactory regulation has been under a legal status. Young people use alcohol much more than one would like to see, yet it is a legal drug. It's simply the case that older people above the legal age for purchasing share it with the younger people. That is even easier to do with cannabis, because it's rather hard to hide a bottle of liquor when you leave the LCBO. It would not be difficult at all to hide a small package of cannabis in your pocket.

The point, therefore, is that the two, both alcohol and cannabis, produce problems. We have used different measures to control them for traditional and historical cultural reasons. The question is, do we wish to repeat the same mistakes with cannabis that we have made with alcohol in not training young people to realize that there are safe limits to what use permits? So far, our record with alcohol does not make us very optimistic about how to achieve that with cannabis.

I think that's why I say it is necessary to be very cautious about changes in policy that may increase the use and make it more difficult still to control, within healthy levels, the extent of use.

[Hedy Fry, Liberal, Vancouver Centre, BC]

Thank you.

Do you have any comments on that, Dr. Kahan?

[Dr. Meldon Kahan]

I would support what Dr. Kalant says. There is evidence from other countries that decriminalization actually does not increase use but actually helps to divert patients who have a problem to addiction treatment. In Portugal, for example, they decriminalized cannabis and it's had very good results.

On the other hand, legalization, as Dr. Kalant says, has been associated with dramatic increases in use and dramatic increases in harm. The two are completely different. I would support, and I think everyone I know would support, the decriminalization of small amounts of cannabis possession, but legalization and making it available in retail stores is a totally different matter.

[Hedy Fry, Liberal, Vancouver Centre, BC]

Thank you, Mr. Chair.

[The Chair, Conservative, Ben Lobb]

All right.

Mr. Wilks, you have seven minutes, sir.

[David Wilks, Conservative, Kootenay—Columbia, BC]

Thank you very much, Mr. Chair.

I'm quite interested in this study, having had a former career as a police officer and three years of drug work. I'm quite intrigued by this.

First, to Dr. Kahan and/or Dr. Kalant, can you tell us what the increase has been since the eighties—I'll arbitrarily use the eighties, but we can go to the seventies, if you so choose—of tetrahydrocannabinol in the patients that you see?

[Dr. Meldon Kahan]

My understanding is that the increase has been quite dramatic since the eighties, not only in the number of people using, especially young people, but also in the potency of the THC, and therefore, the psychiatric and social harms of THC. It may have levelled off in the last few years, I'm not really sure, but it has become very widespread, especially among youth.

[Prof. Harold Kalant]

The cannabis that was available for illicit purchase at the time of the Le Dain commission was in the order of 0.5% to 1% THC. That was the material that was supplied to us from seized material by the RCMP when we began our studies.

The current average for seizure material is between 10% and 15%. There have been isolated cases of concentrations much higher than that. Certainly I would agree that the concentration has increased at least tenfold, possibly twentyfold.

[David Wilks, Conservative, Kootenay—Columbia, BC]

Thank you very much. The best I ever seized was 38%. There is some good stuff out there.

[Voices]

Oh, oh!

[David Wilks, Conservative, Kootenay—Columbia, BC]

The fact of the matter is that because it's unregulated, you do not know what you're getting from time to time.

That would be my next question for both of you gentlemen. With regard to the absorption into tissues of tetrahydrocannabinol, can you tell this committee the absorption rates of THC into the system? How long can it take for that to relieve itself from the body?

[Prof. Harold Kalant]

If you're talking about smoking, the onset of action is almost immediate. The concentration in blood rises rapidly for about the first 10 to 15 minutes. Then it levels off while the concentration in the tissues continues to increase, because the solubility of THC in fatty materials means that it tends to leave the blood and accumulate in the tissues.

Similarly, or rather mirror-image, when it is leaving the body, it leaves the blood fairly rapidly by metabolism and then excretion, but it leaves the tissues slowly. Therefore, it continues to be leached out of the tissues into the blood, carried to the liver where it's metabolized, and then excreted by the kidneys rather slowly over a period of what can be up to three days or more.

[David Wilks, Conservative, Kootenay—Columbia, BC]

Dr. Kahan, have you anything to add?

[Dr. Meldon Kahan]

This is very relevant with respect to recommendations about driving. The current lower-risk cannabis-smoking guidelines that have been put out by Fischer and the Canadian Journal of Public Health suggest that people who use cannabis not drive for at least three to four hours after use. Probably it should be longer than that for oral use—up to six hours—and some have suggested that if the patient experiences euphoria from the cannabis, which suggests a very high drug level, that they not drive for at least eight hours.

[David Wilks, Conservative, Kootenay—Columbia, BC]

I believe it was one of you two gentlemen who commented that no one has overdosed from marijuana, which is true, but no one has overdosed from a cigarette either. No one has ever overdosed from tar and nicotine that I am aware of, not one person. A lot of people have died from it, but never overdosed from it.