Updated: Feb 28, 2021
DUNCAN VAN NEST, BS
ASIF ILYAS, MD, MBA, FACS
ARI GREIS, DO
Medical Cannabis has been growing in utilization across the United States, with the majority of states now allowing its use for medical diagnoses.
The legalization and use of Medical Cannabis has been correlated with decreased opioid use.
The most common use for Medical Cannabis is chronic pain conditions.
Despite growing literature indicating efficacy, Medical Cannabis continues to be listed as a Schedule I drug, therefore limiting prospective, randomized, and controlled clinical research.
Opioid medications are widely used in medicine for the treatment of acute pain, such as in the immediate period following a surgical procedure. However, the treatment of chronic pain is a more complicated issue as long-term use of opioids can lead to tolerance, dependence, addiction, and decreased efficacy. Cannabis and cannabis derivatives have emerged as possible alternatives for the treatment of chronic pain. While many patients find benefit from cannabis use for a variety of medical conditions, clear indications for use, specific mechanism of action, as well as risk profiles are not fully understood as medical research has lagged behind its implementation. If its efficacy can be demonstrated and appropriate indications established for its use, medical cannabis maybe able to reduce the utilization of opioid medications for chronic pain.
Cannabis has been a schedule I drug in the United States since 1961. This means that in the eyes of the federal government, cannabis is a drug of abuse and serves no medical purpose. Despite this drug scheduling from the federal government, various states have loosened restrictions on cannabis over the past two decades as recognition of its role in treating pain and other health conditions has become more widespread. The first state to approve medical cannabis was California in 1996, allowing its select use in treating pain and nausea primarily in AIDS patients. Since then, 33 other states have approved comprehensive, publicly available medical cannabis programs (figure 1).1 Chronic pain is the most common use of medical cannabis. A survey identifying nearly 1000 medical cannabis users from dispensaries in New England indicated that 64% of users at these dispensaries had been diagnosed by a medical professional with a chronic pain condition.2 Other uses for medical marijuana include glaucoma, nausea, anxiety, and seizures, among others.
Figure 1: Map demonstrating the legal status of medical cannabis as of August 1, 2019. Reprinted from National Conference of State Legislatures. State Medical Marijuana Laws. Published March 10, 2020. https://www.ncsl.org/research/health/state-medical-marijuana-laws.aspx
Medical research on cannabis is limited as the schedule I designation has largely prevented high quality, prospective studies from being performed for many years. Thus, the early evidence for and against medical cannabis for treating chronic pain has come largely from retrospective studies and patient surveys with self-reported outcomes. Recent studies that have sparked particular interest in the field of chronic pain and opioid abuse have demonstrated that states with medical cannabis laws have seen reductions in opioid prescriptions filled as well as reductions in opioid-related deaths compared to states without medical cannabis laws (Figure 2).3,4 A subsequent review on this topic has demonstrated a similar effect of reducing opioid prescriptions, however the reduction in mortality benefit was less clear.5 While there are many other regulatory and socioeconomic factors that could be contributing to the results from these observational studies, they may indicate that certain patients have found that substituting medical cannabis for opioids to be an effective alternative for treating chronic pain. In another recent national survey, researchers found that a significant proportion of respondents reduced opioid consumption in favor of cannabis for better pain control, reduction of unwanted opioid side effects and withdrawal symptoms.6
Figure 2: Changes associated in number of Medicaid prescriptions for conditions that may be treated with cannabis with a state’s having legalized medical cannabis. States with legal medical cannabis saw a significant reduction in prescriptions filled for pain-related conditions compared to states without legal medical cannabis by approximately 10%. Reprinted from Bradford AC, Bradford WD. Medical Marijuana Laws May Be Associated With A Decline In The Number Of Prescriptions For Medicaid Enrollees. Health Aff (Millwood). 2017;36(5):945-951
Critics of the medical cannabis movement cite the lack of consensus within the medical community about efficacy, the negative health consequences of smoke inhalation, and the psychoactive properties of cannabis as reasons that use for chronic pain in its current state is inappropriate.7 To mitigate some of these negative side effects of smoked cannabis, increased utilization of cannabidiol (CBD) has been seen in recent years. CBD is an active cannabinoid that is naturally found in cannabis. This particular molecule, in contrast to tetrahydrocannabinol (THC), has minimal psychoactive effect and can be administered via oral ingestion or as a topical formulation. However, since CBD for pain is only available as a supplement and not approved pharmaceuticals, these products are largely unregulated and therefore difficult to assess safety and efficacy. Nonetheless, there is sufficient evidence from patient reports, as well as preliminary data from within the scientific community to support the continued investigation of medical cannabis and cannabis derivatives for the treatment of chronic pain. If these preliminary reports are further supported by high quality, scientific studies, medical cannabis for chronic pain could help decrease the utilization of prescription opioids.
1. National Conference of State Legislatures. State Medical Marijuana Laws. Published March 10, 2020. https://www.ncsl.org/research/health/state-medical-marijuana-laws.aspx
2. Piper BJ, Beals ML, Abess AT, et al. Chronic Pain Patients’ Perspectives of Medical Cannabis. Pain. 2017;158(7):1373-1379. doi:10.1097/j.pain.0000000000000899
3. Bradford AC, Bradford WD. Medical Marijuana Laws May Be Associated With A Decline In The Number Of Prescriptions For Medicaid Enrollees. Health Aff (Millwood). 2017;36(5):945-951. doi:10.1377/hlthaff.2016.1135
4. Powell D, Pacula RL, Jacobson M. Do medical marijuana laws reduce addictions and deaths related to pain killers? J Health Econ. 2018;58:29-42. doi:10.1016/j.jhealeco.2017.12.007
5. Chihuri S, Li G. State marijuana laws and opioid overdose mortality. Inj Epidemiol. 2019;6. doi:10.1186/s40621-019-0213-z
6. Ishida JH, Wong PO, Cohen BE, Vali M, Steigerwald S, Keyhani S. Substitution of marijuana for opioids in a national survey of US adults. PLoS One. 2019;14(10). doi:10.1371/journal.pone.0222577
7. Carr D, Schatman M. Cannabis for Chronic Pain: Not Ready for Prime Time. Am J Public Health. 2019;109(1):50-51. doi:10.2105/AJPH.2018.304593