Medical Marijuana For Intractable Pain - The Minnesota Update

Minnesota made headlines at least within the state lately by qualifying intractable pain (typically known as chronic noncancer pain) as a condition for Minnesota's Medical Cannabis program.  I find it politically interesting that when you want to take over medical systems of care the strategy is to eliminate the word medical wherever that is possible.  But in this case when there is limited if any medical evidence for a treatment that carries significant risks and the initiative seems like part of a political movement toward the general legalization of marijuana that the word medical is added to seemingly legitimize the entire process.  I don't think that there is anything medical about marijuana or cannabis.  If you want it legalized, make that argument and don't pretend that a compound (or more appropriately compounds)  that has been around for 5,000 years has suddenly become a miracle drug.  

I previously posted about the original statute and will not repeat any of that in this post.  The full details of the intractable pain indication are listed on a separate DHS web site including the definition of intractable pain.  The statutory definition of intractable pain is quite complicated and seems to misunderstand the nature of chronic pain, ignore the addiction cofounder, and address the non-cannabis treatment of chronic pain with Schedule II to V drugs and issue that seems totally unrelated to cannabis use.  To cite a couple of examples:

"§ Subdivision 1.Definition. For purposes of this section, "intractable pain"means a pain state in which the cause of the pain cannot be removed or otherwise treated with the consent of the patient and in which, in the generally accepted course of medical practice, no relief or cure of the cause of the pain is possible, or none has been found after reasonable efforts. Reasonable efforts for relieving or curing the cause of the pain may be determined on the basis of, but are not limited to, the following:

(1) when treating a nonterminally ill patient for intractable pain, evaluation by the attending physician and one or more physicians specializing in pain medicine or the treatment of the area, system, or organ of the body perceived as the source of the pain; or...." 

With chronic noncancer pain is is generally accepted that there is no medical treatment that will eliminate the pain.  There is no medication that will totally alleviate the pain.  That includes high potency opiate medications.  Most of the literature suggests that whether high potency opiates, anticonvulsants, ar antidepressants are used the result is a moderate amount of pain relief at best and additional measures like physical therapy and psychotherapy are needed to produce optimal results.  There is really minimal to no evidence that the addition of cannabis to existing pain medications will add anything.  In this case, the statute also suggests that all of these pain patients will be referred to "one or more physicians specializing in pain medicine" or the part of the body that the pain is associated with.  This statute seems like it could easily set-up a physician or group of physicians who could add cannabis to the medications that they are already prescribing.  In other words the statute is providing a non-medical indication that can be used to alter medical practice on a large scale by the prescription of an addicting drug.  We have seen previous epidemics of use and overprescribing based on similar theories.

Subd 2. from the same statute gets in to existing medical practice for reasons that are not apparent to me.  It includes the following introductory paragraph and goes on to cite the non-applicability of the statute to the issue of treating substance use disorders, use for non-therapeutic purposes, providing a scheduled drug for the purpose of terminating life in a person with intractable pain, and using a non-approved drug.  Based on my experience Schedule II-V drugs are widely used for non-therapeutic purposes if use for any indication outside of analgesia is considered a non-therapeutic purpose.  A few examples include taking extra medication for insomnia, anxiety, depression as well as mixing the medication with alcohol for an added effect.  It seems more than a little naive to me to think that a controlled substance with broad effects on the conscious state that potentially reinforces its own use will be not be used for other purposes.  That includes the use of cannabis and marijuana.        

"§ Subd. 2.Prescription and administration of controlled substances for intractable pain. Notwithstanding any other provision of this chapter, a physician may prescribe or administer a controlled substance in Schedules II to V of section 152.02 to an individual in the course of the physician's treatment of the individual for a diagnosed condition causing intractable pain. No physician shall be subject to disciplinary action by the Board of Medical Practice for appropriately prescribing or administering a controlled substance in Schedules II to V of section 152.02 in the course of treatment of an individual for intractable pain, provided the physician keeps accurate records of the purpose, use, prescription, and disposal of controlled substances, writes accurate prescriptions, and prescribes medications in conformance with chapter 147."

There is some science added to the Intractable Pain page in the form of a review entitled: Medical Cannabis For Non-Cancer Pain-A Systematic Review.  It was prepared in the standard manner of most current literature reviews critiquing the quality of the studies and looking at what the evidence shows.  Most people who are uninterested in the details of these reviews could benefit from reading the executive summary.  Like most of these systematic reviews the authors conclude that the overall evidence is sketchy, that a few studies established a response better than placebo, that the clinical trials are of short duration and patient selection is not likely to reflect who might use the drug in Minnesota, and that most of the trials looked at adjunctive treatment of cannabis and limited forms rather than cannabis monotherapy.  They also conclude that cannabinoids were associated greater risk of any adverse events, serious adverse events, and events associated with withdrawal from the study than placebo.  The authors were aware of a recent review in JAMA provided an interesting analysis of that data in the context of their review on pages 22 and 23.  The authors point out that their review (unlike the JAMA review) did not use data from unpublished studies in the meta-analysis of treatment effects.  Their re-analysis of the JAMA review data generally shows either evidence that does not show superiority over placebo or in the case where it does - the evidence is of low or insufficient strength.

I am not going to include an exhaustive review of the toxicity of cannabis or the developmental concerns of cannabis exposure in utero or in the developing adolescent brain.  I am considering a separate post on that topic.  For the purposes of an intractable pain post,  I will add a couple points about politics and regulation.  The first point is that chronic pain is a complex disorder.  It resembles what is commonly conceptualized as a psychiatric disorder much closer than what is considered a standard medical or surgical disorder.  Chronic pain is multidimensional and is frequently associated with depression, anxiety, and insomnia.  Pain ratings on any given day can reflect the state of those other conditions.  Cannabis can affect all of those other conditions in unpredictable ways.  The best example I can think of is the chronic marijuana smoker who starts in order to treat anxiety and stops years later because the anxiety is worse and he is now experiencing panic attacks or paranoia.  Anything that complicates the other dimensions of chronic pain will not be an acceptable overall treatment.  The second point is that some chronic pain patients end up taking a drug in an addictive manner independent of pain relief.  That is true for marijuana, opioids, and benzodiazepines.  Many patients will openly admit that they are using the drug because they like the effects, but it is not doing a thing for their pain.  The final point is that some people do not discriminate between numbness and analgesia.  The drug they take for pain has to induce a numb state - one where they generally have a difficult time functioning.  I include these points about chronic pain trials because these additional phenomena are usually not examined in the clinical trials.  The trial occurs as if every subject can rate their pain like they can take a blood pressure reading and that loses a lot of important information in the process.  The studies in the reviews listed here for cannabis in non-cancer pain can show weak positive effects and those kinds of studies will eventually be approved by the FDA as evidenced by some FDA actions where the regulatory considerations trump the scientific ones.  With marijuana being described as a fast growing $3 billion dollar a year business with a projected maximum market of $36.8 billion annually, you can bet there will be a large commercial lobby pushing for approval of whatever products they want to bring to market.  

I don't plan on getting too riled up about the Minnesota experiment and the political indications for "medical" marijuana.  It is clearly a response to the current cultural swing to view cannabis as a benign product and use the medical avenue to get total legalization.  When marijuana use gets as widespread as alcohol use, the population toxicity will be more evident.  In the meantime, I hope physicians don't get pulled into the politics - especially psychiatrists.

I don't plan on registering on the Medical Cannabis Registry and certifying patients for the political indications for its use.  I consider that to be a foolish endeavor.  It would be much easier to take physicians out of the loop instead of having them pretend to select patients for a drug with no medical indications.  If anything, the widespread use of marijuana or cannabis for whatever the reason will complicate psychiatric practice and increase the costs of treatment that is already rationed by healthcare businesses and the government.  


George Dawson, MD, DFAPA

Refs:

1:  Butler M, Krebs E, Sunderlin B, Kane RL.  Medical Cannabis for Non-Cancer Pain: A Systematic Review.  Prepared for: Office of Medical Cannabis Minnesota Department of Health, October 2015.

2:  Whiting PF, Wolff RF, Deshpande S, et al. Cannabinoids for Medical Use: A Systematic Review and Meta-analysis. JAMA.2015;313(24):2456-2473. doi:10.1001/jama.2015.6358.


Attribution:

Jennifer Martin (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons at: https://commons.wikimedia.org/wiki/File%3AMarijuana_Plant_01.JPG