Education Key When Considering Prescribing Medical Marijuana

LAS VEGAS — Clinicians should educate themselves and their patients if they choose to use medical marijuana in their practice, according to Michael E. Schatman, PhD, a clinical psychologist who has spent decades working in multidisciplinary chronic pain management. He presented on this topic during a session this week.

Much has been published on medical marijuana within the past year, but the data on safety are not encouraging and data on clinical efficacy are very limited. Generally, the quality of research from countries like Israel and Brazil has been much better than that from the United States because the laws governing research are different in those countries, Dr. Schatman explained.  However, help may be on the way in the form of the 21st Century Cares Act. The law was recently amended to facilitate medical cannabis research, rescheduling it from a 1 to a 1-R designation, likely “making it easier to do good research,” he said. The act calls for an additional $1.75 billion in National Institutes of Health funds.

Currently, all federally funded medical marijuana research must use low-grade marijuana grown at the University of Mississippi. He said this marijuana comes in 3 different dosage strengths: low at 1.29%  tetrahydrocannabinol (THC), moderate potency at 3.53%, and high potency at 7%.1

These potencies present a challenge, Dr. Schatman said, because  published data from Mehmedic  et al showed that the average THC of government-seized marijuana increased from 3.4% to 8.8%,2 meaning that the cannabis that is being tested for medicinal use is not the same as what many patients may be using recreationally.  Dispensaries carry cannabis strains as high as 33% THC.

There are new clinical efficacy data related to medical marijuana, Dr. Schatman noted, but they are generally data from other countries. He cited one study out of Australia that concluded medical marijuana was associated with a 70% reduction in chronic pain symptoms. However, he cautioned that this study made no mention of the constituents of the marijuana used or the types of pain.3

An American study of medical marijuana for patients with diabetic neuropathic pain concluded that a 7% THC formulation worked better than a 4% or a 1% formulation, but it also resulted in more cognitive impairment.4

Much of the other data published this year regarding marijuana use has surrounded lack of safety, Dr. Schatman explained, but research into cannabidiol is showing some early positive therapeutic effects as well as carrying a strong evidence basis for safety.

Discussing safety of medicinal marijuana use, Dr. Schatman cited data demonstrating that smoking remains the most common route of administration,5 and a recent review showed that pulmonary effects may be worse than previously thought.6 These data are sometimes difficult to interpret, however, Dr. Schatman said, because many people who smoke marijuana also smoke tobacco.

Although research into cannabidiol is “just starting,” Dr. Schatman cited several studies that show its safety has been established when coadministered with fentanyl,7 that it enhances fracture healing,8 and has been associated in animal models with protective effects on lesion-induced intervertebral disc degeneration.9 

Discussing research abroad, Dr. Schatman noted that nabiximols is now approved in 27 countries  but not in the United States. He said clinical efficacy has been established for spasticity associated with multiple sclerosis10 and neuropathic pain.11

“We need to look at isolated constituents–primarily cannabidiol–in order to maximize analgesia and functionality,” Dr. Schatman explained.  He added that based on the currently available data, there is no good way of predicting the impact of medical marijuana on specific patients, explaining that “any pill can do anything to any person at any time.”

Dr. Schatman expressed frustration with what he referred to as “medical marijuana neuromysticism,” whereby zealous proponents of the drug tend to ignore the existing empirical data, seeking to guide practice based upon what they simply want to believe.

Dr. Schatman concluded his presentation by directing clinicians to an article published ahead of print in the Clinical Journal of Pain that outlined a “medicinal cannabis treatment agreement,” calling it “absolutely brilliant.”

Highlights of these agreements are that they can help physicians address inappropriate utilization by the authorized patient and prompt discussion of the risk of marijuana generally and to specific populations.

“We must not lose sight of the data indicating that marijuana is indeed addictive,” he said.

Dr. Schatman noted he is on the speaker's bureau for Mallinckrodt.

References

1. Wilsey B, Marcotte T, Deutsch R, Gouaux B, Sakai S, Donaghe H. Low-dose vaporized cannabis significantly improves neuropathic pain.  J Pain. 2013;14:136-148.

2. Mehmedic Z, Chandra S, Slade D, et al. Potency trends of Δ9-THC and other cannabinoids in confiscated cannabis preparations from 1993 to 2008.  J Forensic Sci. 2010; 55:1209-1217.

3. Degenhardt L, Lintzeris N, Campbell G, et al. Experience of adjunctive cannabis use for chronic non-cancer pain: findings from the Pain and Opioids IN Treatment (POINT) study. Drug Alcohol Depend. 2015;147:144-150.

4. Wallace MS, Marcotte TD, Umlauf A, Gouaux B, Atkinson JH. Efficacy of Inhaled cannabis on painful diabetic neuropathy. J Pain. 2015;16:616-627.

5. Fitzcharles MA, Clauw D, Ste-Marie PA, Shir Y. The dilemma of medical marijuana use by rheumatology patients. Arthritis Care Res. 2014;66:797-801.

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