Marijuana for Arthritis and Pain: Is There a Role?

Bret S. Stetka, MD


June 25, 2014

In This Article

So Does Cannabis Belong in the Clinic?

The overarching theme of much of Fitzcharles' talk was that the majority of the medical community seems reticent to fully embrace medical marijuana, on the basis of the current body of knowledge. Despite the availability of purified THC formulations, most marijuana used for medical purposes is smoked -- not a practice encouraged by most physicians, because it could come with inhaling numerous potentially toxic substances. In addition, the wildly different THC concentrations -- ranging from 1% to 30% -- in today's marijuana strains and varied bioavailability make it incredibly tough to dose with any accuracy.

Fitzcharles feels that beyond limited efficacy data and nonstandardized formulations, the use of cannabis in rheumatic and other conditions is further hindered by potential acute risks.

Short-term use alters sensory perception, temporarily impairs memory, and induces thought fragmentation. Psychomotor effects are common, as are mood alterations and even -- perhaps paradoxically given marijuana's relaxed reputation -- anxiety. However, Fitzcharles continued, "Pain relief...that's good. That's what we're looking for." Then, speaking about the potential benefits of medical marijuana, she continued, "and increased appetite might be good for wasting diseases."

Another ding for medical cannabis are potential cardiovascular risks including tachycardia and, per a new French study,[12] an increased rate of cardiovascular events. But then again, cannabis has also been shown to decrease blood pressure. In short, the jury is still out.

Fitzcharles then highlighted a Dutch study[13] looking at the cognitive effects of acute marijuana use in young, healthy regular users. Participants smoked marijuana in a monitored research setting, and various mental faculties were assessed. Even in seasoned users, there were marked dose-related reductions in reaction time, selective attention, short-term memory, and motor control. A recent meta-analysis correlated acute cannabis use with twice the risk for injury or death by motor vehicle accident.[14]

Fitzcharles then pointed out that cannabis use also comes with increased risk for psychological disorders, such as psychotic disease, depression, and anxiety, as well as suicide. Also, despite frequent rumors to the contrary, there is a risk for dependence and abuse associated with cannabis use. Psychological dependence appears to be equal to that of alcohol and occurs in at least 8% of users within 1 year of starting marijuana use. Even pharmacologic formulations can be abused, but they're expensive -- and, somewhat ironically, not as easy to come by for many.

"We need to distinguish herbal vs pharmacologic cannabis preparations, and also think about the increased risks that come with use of any kind," said Fitzcharles, nearing the end of her talk, before concluding that the cannabinoid system appears to be quite important in rheumatic disease and that researchers and clinicians should push for research to better understand how this system is involved in rheumatologic disease and how cannabinoid therapies could be beneficial. In her opinion, pharmacologic preparations are a more desirable approach, given that smoking herbal cannabis comes with many medical and societal questions. Ideally, a medicinal compound would be more therapeutically targeted and less psychoactive. In addition, she feels strongly that clinicians should discourage their patients from smoking cannabis.

After the talk, California Pacific Medical Center rheumatologist and Session Co-chair Neal Birnbaum, MD, commented that he lives near some of the best marijuana in the United States -- adding, "So I'm told," to audience laughter -- and that many patients walk out with a marijuana and a hydrocodone script. "I'm not sure they realize how serious this is," he commented.


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