When people have chronic pain they often experience other problems such as anxiety, avoidance behaviors, depression and difficulty with falling or staying asleep. Cannabis-based products have the potential to manage several of these conditions, however many healthcare providers are unfamiliar with their appropriate use and risk. Indeed, many rehabilitation professionals regularly encounter patients who ask questions about over-the-counter medications and supplements to help manage pain and other conditions and now, with adult use cannabis legal in over 20 states, patients are asking about cannabis. Knowing how to respond can be quite challenging.
Coming to the rescue are two papers written by experts in the field of cannabis and cannabinoid research. The first, published in 2021, provides recommendations for the administration and dosing of cannabis in the treatment of chronic pain. Using a modified Delphi process, which is often used when there are important questions to be answered, but randomized clinical trials (RCTs) are limited or lacking, a global task force of twenty medical experts reached a consensus in how to best administer cannabis and monitor people with chronic pain based on the best available scientific evidence and their clinical experiences.
Here is a figure from Bhaskar et al (2021) that describes a conservative protocol for medical cannabis dosing and administration.
To see descriptions of routine and rapid protocols, information about follow-up and monitoring, and recommendations for those who should avoid cannabis go to Bhaskar et al (2021).
The second paper, based on the best available scientific literature is a clinical practice guideline (CPG). It provides information about the efficacy of cannabis for managing chronic pain and other associated conditions such as sleep problems and anxiety. The CPG also addresses cannabis use in some chronic conditions such as fibromyalgia and arthritis which are typically associated with pain. As with most CPGs, the authors provide a range of recommendations (weak, moderate, strong) and inform the reader about the quality of the evidence (very low, low, moderate, high). The authors of this CPG also provide a “values and preferences statement and “practical tips” when indicated, which can be helpful when cannabis-based products are either available or not available based on state jurisdictional laws.
Below is an example of a recommendation, values and preferences and practical tips for using cannabis-based medicine (CBM) with people who have chronic pain and experience anxiety.
Recommendation: We recommend the use of CBM as adjunct therapy to improve symptoms of anxiety in people living with chronic pain not responsive to, or intolerant of non-pharmacologic treatment.
Strong Recommendation, Moderate-Quality Evidence
Values and preferences: The recommendations place high value on the benefit of CBM for anxiety symptoms over the risks of adverse events of a mainly non-serious nature such as dry mouth, disturbance in attention and memory, as well as the potential for acute transient increases in anxiety and panic.
Practical tip: The only RCT to compare doses of herbal cannabis suggested that chemovars (strains) with 9% THC—which would be generally considered a moderate to low strength herbal cannabis—are more effective than herbal cannabis with low to very low levels of THC, regardless of CBD content. To limit exposure to adverse events, individuals should follow a structured initiation and titration plan. (See Bhaskar et al 2021)
Practical tip: Other modes of administration might also be advantageous; specifically, orally ingested CBMs provide the greatest consistency for dosage and titration, are not associated with potential adverse events associated with inhalation of CBM, and may also offer advantages in the context of sleep disturbance that may be prominent among some individuals with problematic anxiety.
Practical tip: It is well recognized that THC has the potential to trigger acute transient increases in anxiety and panic. Individuals should be warned of this adverse effect and closely followed for it.
Not all conditions included in the CPG rendered a strong recommendation for CBM and there are many conditions for which the quality of the evidence is low. To fully appreciate the current state of the CBM scientific literature, its adverse effects and additional safety concerns, please read Bell at al 2023, available through PubMed.
As always, it's important to consider the tenants of evidence-based practice when any intervention is being considers: 1) the best available scientific evidence, 2) patient values and preference, and 3) the clinician's expertise. We hope these resources prove to be valuable in being able to partner with and educate people with chronic pain and other related conditions.
References
Bell, A. D., MacCallum, C., et al. (2023). Clinical Practice Guidelines for Cannabis and Cannabinoid-Based Medicines in the Management of Chronic Pain and Co-Occurring Conditions. Cannabis and Cannabinoid Research, 10.1089/can.2021.0156. Advance online publication. https://doi.org/10.1089/can.2021.0156
Bhaskar, A., Bell, A., et al. (2021). Consensus recommendations on dosing and administration of medical cannabis to treat chronic pain: results of a modified Delphi process. Journal of Cannabis Research, 3(1), 22. https://doi.org/10.1186/s42238-021-00073-1