Medical Marijuana Use as An Alternative to Opioid Use for Relief of Chronic Pain

A Michigan Survey Suggests That Medical Marijuana Patients Are Decreasing Opioid Use to Treat Chronic Pain

Two topics that have received a great deal of attention in recent years regarding the medical treatment of chronic pain have been the use and abuse of opioids such as Vicodin and the legalization in many states of medical marijuana. Although one often-used argument for keeping marijuana use illegal has been that the drug might be used as a “gateway” to the use of other drugs, the use of medical marijuana might actually lead to a decrease in the use of addictive opioids as a treatment for chronic pain. In “Medical Cannabis Use Is Associated With Decreased Opiate Medication Use in a Retrospective Cross-Sectional Survey of Patients With Chronic Pain,” published in the June 2016 issue of The Journal of Pain, researchers from the University of Michigan surveyed users of medical marijuana looking for some insight into the relationship between medical marijuana use and alternatives such as opioids for chronic pain management.

Methodology

For this study, the researchers conducted an online survey with 374 participants recruited from November 2013 to February 2015 through a Michigan medical marijuana dispensary, although they extracted most of their data from the 185 survey participants who fully completed the survey. Almost two-thirds of these were men, and all 185 identified chronic pain as a target condition. 39% were between 18 and 35 years of age, 31% between 36 and 55, and 30% between 56 and 75.

In addition to demographic information about the participants, the survey included questions eliciting information about the medical conditions being treated with medical marijuana, the frequency of marijuana use, changes in drug use since marijuana use began, changes in side effects, and quality of life changes. Some of the questions required participants to provide a measure of intensity on a scale of one to ten, with one being the least amount and ten the greatest for that particular question. All participants also completed the Fibromyalgia Survey Criteria, which assigned an FM score from 0 to 31, with the higher score indicating more severe FM pain at the time of the survey. These FM scores were used to group all participants into quartiles for purposes of analysis.

Survey Results

Of the 185 participants with fully completed surveys, 79% of the participants reported daily marijuana use and another 12% reported 4 to 6 uses a week. On days when marijuana was used, 20% reported using it at least 5 times on that day, 42% reported using it 3 to 4 times that day, 25% used it twice that day, and only 12% reported limiting use to only once on usage days.

Among the fully-completed surveys, the mean change in reported opioid use after beginning medical marijuana use was -64%, with 119 participants reporting opioid use before beginning marijuana treatment and only 33 reporting opioid use after initiating marijuana use. However, this decrease in opioid use was not consistent through the 4 FM quartiles, with the lowest FM quartile, i.e., those showing the least amount of FM pain, reporting an opioid usage decrease of 79%, while those in the highest FM quartile reported an opioid use decrease of only 48%. The second and third quartiles showed decreases of 74% and 63%, respectively. This outcome ran counter to what the researchers expected to find, as earlier studies had suggested that persons with higher FM scores, suggesting that the central nervous system was playing a greater role in pain, were less likely to benefit from opioids and more likely to respond better to marijuana for pain relief.

The survey also measured the number of medication classes used before and after marijuana treatment was started, with classes including not just opioids, but also NSAIDs, antidepressants, disease-modifying antirheumatic drugs, serotonin-norepinephrine reuptake inhibitors, selective serotonin reuptake inhibitors, and other. Among all participants, the number of reported medication classes used dropped from a mean of 2.38 before marijuana use to 1.81 after marijuana use began, although that latter number included the marijuana itself, so the mean drop in use of non-cannabis medication classes was actually from 2.38 to .81. For example, in addition to the opioid numbers described above, 115 participants reported using NSAIDs before beginning marijuana treatment, while only 38 reported such use after. Antidepressants usage decreased from 72 participants before marijuana treatment began to only 25 participants after. Participants in the highest FM quartile, who reported the highest number of medication classes used before marijuana use began, 3.3, continued to report a higher number than the other quartiles after marijuana use began, although the number of classes for even that quartile dropped to 2.4.

Participants also self-reported a decrease in medication side effects after beginning medical marijuana treatment, as well as in the degree to which side effects of medication affected daily function, described in the survey as the “ability to do the things you needed to accomplish each day.” On the 1-to-10 scale, where 1 meant there was no effect and 10 meant a significant effect, the mean score describing daily impairment in the period before marijuana use began was 6.51, while the mean score describing the period after marijuana use began was down to 2.79. While this suggests that participants self-reported being able to handle their daily functions better after marijuana use began, there is no way of knowing from this survey the extent to which the effects of marijuana use on participant mood might have influenced the answer to this question.

Limitations

While this research provides at least a starting point for evaluating the use of medical marijuana as a treatment for chronic pain as a potential alternative to opioid usage, the researchers note some drawbacks to their survey data, including the unreliability of recall data generally, the fact that the FM scores were measured only at the time of the survey and not at the earlier time when medical marijuana use began, and the limited pool of participants compiled from one medical marijuana dispensary. They also recognized that the reduction in opioid use they found after medical marijuana use began could have been caused by other factors, given the efforts that have been made to reduce opioid prescriptions generally, although they note that in Michigan the reported number of opioid prescriptions consistently increased from 2007 to 2014. As the researchers note, however, efforts to overcome these limitations suggests a path for further research to take in this area.

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