Medical Marijuana Should Never Be Smoked; the medical profession should work to keep smoking marijuana illegal.

Arizona physicians, health care providers & concerned citizens: Please contact Arizona Department of Health Services (DHS) by January 7, 2011 to give feedback on the proposed regulations for medical marijuana.  Once there, click on the Electronic Comment Form. This post is my description of one of the most important regulations that DHS can impose to make this a real medical marijuana law and not just a backdoor route to legalization.

Arizona’s “medical marijuana” law passed in November 2010 by just over 4000 votes, 0.2% of all votes cast. I opposed it because it’s not really about medical marijuana, it’s designed so almost all the marijuana goes to recreational users. Had it been an honest medical marijuana law that gave most of the marijuana to genuinely ill people who would be helped by it, I never would have opposed it. There are real instances in which cannabinoids can provide relief of symptoms. Now that it has passed, we should make sure the law provides medical marijuana, not recreational marijuana.

First of all, marijuana for medical use should never be dispensed in a form that can be smoked. Marijuana can be made into capsules or suppositories or cooked into food, but marijuana smoke contains dozens of carcinogens. Preliminary research shows that smoking marijuana can increase the risk for respiratory problems and several types of cancer–lung, head and neck, testicular and bladder. This post reviews much of the research. The medical profession and others in public health have made a huge effort for several decades to eliminate the smoking of tobacco because it’s such a serious health hazard, and doctors should not recommend any substance to be smoked.

Following the adage, “First, do no harm,” doctors should always prescribe medications by the least harmful route of administration. And, in fact, we always try to give medications orally. For people whose illness makes it hard to take a pill or to keep one down, we have skin patches and suppositories. The last resort is injecting medicine. But there is no precedent for a medication that is smoked. To my knowledge, there is no medicine prescribed today that is smoked,  and for good reason. Smoking causes cancer and lung damage. And there is no need for a medication that is smoked; there is nothing that smoking accomplishes from a medical point of view that can’t be accomplished by safer routes of administration.  Arizona, and other states with medical marijuana laws, should forbid the dispensing of medical marijuana in any form that can be easily smoked.

Here’s some of the research on problems caused by smoking:

Research has shown that marijuana smokers have several respiratory tract changes, including lesions that are considered pre-cancerous. So far there is no evidence of emphysema, but smoking marijuana does cause problems with airflow obstruction.

There are a small number of studies of cancer in marijuana smokers, some positive, some negative.   Negative studies are quite common in research, and all they mean is this particular study did not find this particular result. Negative studies are not proof unless it happens repeatedly and there are no positive studies. However, many pro-marijuana websites and media outlets have taken a single negative study and claimed marijuana does not cause cancer. There are also articles designed to look scientific that make this claim.  This is an incorrect reading of the research.

Two studies did show no increase in cancer in marijuana users, but both studies have been criticized for bias. One large study (Tashkin 2006) of 1200 people with head, neck and lung cancer showed no increase in cancer in marijuana smokers. Tashkin was the same researcher who had previously found that marijuana caused pre-cancerous changes in the respiratory tract, so he was surprised to find no increased cancer risk.  That large study has been criticized for selection bias—marijuana users in the control group were more likely to also smoke cigarette than the marijuana users in the group with cancer. The authors admitted selection bias possibly explained their negative findings.

One other study published in the American Journal of Public Health in 1997 (Sidney et al) that found marijuana smokers had no increase in cancer has been criticized for using subjects who were too young, so cancers would not have had time to develop.

There are several research studies showing increased cancer rates in marijuana smokers.

A New Zealand study published in the European Respiratory Journal in 2008 looked at 79 patients with lung cancer and found the risk of lung cancer increased by 8 percent for every joint-year (averaging one joint daily for one year) and 7 percent for every pack-year (averaging one pack of cigarettes daily for one year), leading them to conclude that smoking marijuana posed the same lung cancer risk as smoking cigarettes.

Three North African case studies showed a very strong link between marijuana smoking and lung cancer, but none of these studies controlled for tobacco use, so these results are questionable.

A 2009 study done at the Fred Hutchinson Cancer Research Center in Seattle and published in the journal Cancer found that men who smoked marijuana once a week had twice the risk of testicular cancer when compared to men who never used marijuana, and marijuana was most strongly linked to nonseminoma, the most aggressive form of testicular cancer.

Research published in the journal Urology in 2006 showed increased rates of bladder cancer in marijuana smokers. They also found that marijuana-smoking patients were younger at the time of diagnosis than most patients with bladder cancer. Cigarette smoking is a major risk factor for bladder cancer, but the researchers concluded that smoking marijuana may be as bad or worse than cigarette smoking as
a risk factor for bladder cancer.

In 1999, a study published in the journal Cancer Epidemiology found that squamous cell carcinoma of the head and neck increased with marijuana use and there was a strong dose-response curve, the heavier marijuana users had higher rates of cancer. However, in 2004, a study published in Cancer Research found no association between marijuana user and squamous cell carcinoma.

This is not a complete list of studies, and there aren’t many. So it is not enough to draw definitive conclusions on marijuana and cancer. However, the evidence that marijuana smoking is linked to cancer is far more substantial than the research supporting marijuana as treatment for many of the disorders listed in Arizona’s new medical marijuana law.  Also, remember, it took decades of heavy tobacco use by large swaths of the population before we had a definitive link between tobacco smoking and cancer. Meanwhile, cigarette smoking killed Franklin Roosevelt, Humphrey Bogart, Edward R. Murrow, and tens of thousands more. The rule in the field of medicine is when in doubt, err on the side of caution. Caution says if preliminary evidence shows that marijuana smoking probably causes cancer, treat it as if it definitely does.

On several pro-marijuana websites I found the claim that there is no direct evidence linking marijuana smoking to lung cancer in humans. That is exactly what the tobacco industry said for decades after the first studies came out linking cigarette smoking with lung cancer. What they said was technically true; until recently we did not know for certain the exact mechanism by which smoking caused cancer. However, the statistical evidence was overwhelming, so the tobacco industry was being completely disingenuous and so are the pro-marijuana groups who say marijuana doesn’t cause cancer. Anyone who claims that marijuana does not cause cancer is ignoring the research.

Also, in November 2010 an article printed in the European Journal of Immunology described a possible mechanism by which smoking marijuana causes cancer and the research supporting this possible mechanism. If further studies support these findings, then we will have direct evidence linking marijuana smoking to cancer in humans.

Anyone who goes on the internet will find the pro-marijuana groups misrepresenting research. What they almost always do is take one study or one bit of information and run with it as if that were the whole story. That’s how Arizona ended up with a law that says marijuana is good for glaucoma even though the Glaucoma Foundation warns patients not to use marijuana because it could make their symptoms worse.

The American Cancer Society points out on its website that it’s hard to study marijuana and cancer because so many marijuana users also smoke cigarettes and because it’s hard to study illegal drugs. British cancer researchers noticed the same problem.

However, one part of the research is very clear. We know for certain that marijuana smoke contains many of the same carcinogens as tobacco smoke, produces more tar than tobacco, and that the way people smoke marijuana (down to the roach, unfiltered, inhaling deeply, holding it in) delivers more tar to the lungs than the way people smoke tobacco.

California’s Office of Environmental Health Hazard Assessment ruled in 2009 that marijuana smoke is carcinogenic. They are not calling the marijuana plant a carcinogen, just the smoke. That seems right; the research shows a link between smoking marijuana and several types of cancer also commonly caused by smoking tobacco. There is no evidence that ingesting marijuana by other methods causes cancer.

Smoking marijuana is also linked to respiratory problems. Research shows that marijuana smokers have decreased respiratory function, increased airflow obstruction, and fewer of the anti-oxidants that protect against cancer and heart disease.

In summary, smoking marijuana has been implicated in several health problems including cancer. Not definitively, but enough evidence to make it likely. So no doctor should be recommending marijuana in a form that can be smoked. And states with medical marijuana laws, including Arizona, should not allow such a potentially dangerous route of administration.

Marijuana can be mixed into food, formed into a suppository, or cooked in vegetable oil or butter and put into a capsule. Dispensaries should only be allowed to dispense marijuana in these forms, and they should not be allowed to sell marijuana in a form that can be smoked.

Marijuana users have responded to the harm of smoking by developing vaporizers so they can continue to inhale cannabinoids without the dangers of smoking.  However, the reason for vaporizing marijuana is still to get a quick high, just like smoking it. It still offers no medical advantage over taking cannabis orally or rectally, and it allows marijuana to be dispensed in the same form that can be smoked, allowing diversion. Besides, the vaporized product has not, to my knowledge, been tested for carcinogens.

So I strongly suggest the following addition to Arizona Department of Health regulation R9-17-311, and I recommend similar laws for every state with a medical marijuana law:

7. Marijuana may not be dispensed in its raw form or in any form that can easily be used by smoking it. Marijuana should only be dispensed in forms that can be taken orally, such as in foods or mixed with oil or butter and made into capsules, or rectally, as in suppositories. The dispensary will keep records listing the form in which the marijuana is dispensed.  Marijuana for medical use cannot be transported in its raw form. It must be turned into a dispensable form within 100 feet of the place where it is grown.

All marijuana dispensaries must post a warning that can be easily seen by anyone purchasing medical marijuana. The warning states: “Marijuana smoke contains known carcinogens and has been determined to be carcinogenic by ADHS.  Medical marijuana can only be dispensed in forms that are taken orally or rectally. Smoking marijuana obtained for medical use is considered illegal diversion and can be prosecuted. Possessing raw marijuana and smoking marijuana are still illegal under Arizona law.”

The rule against transporting marijuana in its raw form will also help law enforcement because, in other states with medical marijuana laws, it is a common practice for drug dealers to get marijuana cards so they can claim the marijuana they are carrying around is for medical use.

The known carcinogen statement is taken from California’s Office of Environmental Health Hazard Assessment.

Arizona physicians, other health care providers and all concerned citizens who agree that smoked marijuana should remain illegal should go to the Department of Health Services website before January 7, 2011 and register their opinion on the Electronic Comment Form. Also, please read the proposed regulations and give feedback on that as well. They will be getting huge numbers of comments from people who want to divert marijuana to recreational use. They need to hear from the rest of us as well.

About Edward Gogek

I've been practicing psychiatry for 25 years, doing general work with adults, children and adolescents. My subspecialties are addiction psychiatry, classical homeopathy and nutritional medicine.
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One Response to Medical Marijuana Should Never Be Smoked; the medical profession should work to keep smoking marijuana illegal.

  1. Pingback: A doctor’s opinion: Medical marijuana should never be smoked | alcohol, tobacco and other drugs

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