Chronic pain is a common condition that affects one in five people globally. It can have a significant impact on their quality of life, sleep, mental health, and substance use. Many people with chronic pain use cannabinoid-based medicines (CBMs), which are derived from the cannabis plant, to manage their symptoms. However, there is a lack of clear and consistent information on the benefits, risks, and optimal use of CBMs for chronic pain and co-occurring conditions.
To address this gap, a team of researchers conducted a systematic review of studies that investigated the use of CBMs for chronic pain management. They also developed updated clinical practice guidelines based on the evidence from the review. Their findings were published in the journal Cannabis and Cannabinoid Research in March 2023 (Alan D Bell et al. 2023).
The review included 19 systematic reviews and 51 original research studies published between 2007 and 2018. The studies used different types of CBMs, such as synthetic cannabinoids, cannabis extracts, purified phytocannabinoids, or whole plant cannabis.
The review found that CBMs may provide benefit for chronic pain reduction, especially for neuropathic pain. CBMs may also help with some co-occurring conditions, such as sleep problems, anxiety, appetite suppression, and symptoms of HIV, multiple sclerosis, fibromyalgia, and arthritis.
The review also found that CBMs may cause some adverse events, such as drowsiness, dizziness, nausea, diarrhea, dry mouth, and disturbances in attention. These adverse events were usually mild to moderate in severity and similar across different types of CBMs. However, some CBMs may increase the risk of adverse events more than others. For example, oral synthetic cannabinoids with high THC-to-CBD ratios (>98% THC) and extracted cannabinoids with high THC-to-CBD ratios may have more adverse effects than sublingual spray with comparable THC-to-CBD ratios.
Based on the evidence from the review, the researchers developed clinical practice guidelines to help clinicians make informed decisions about CBMs use for chronic pain and co-occurring conditions. The guidelines include recommendations on patient education, assessment, dosing, titration, administration routes, monitoring, and discontinuation of CBMs. The guidelines also provide values, preferences and practical tips to support clinical application. The strength of the recommendations and the quality of the evidence were rated using the GRADE system. The level of recommendation for CBMs in a particular condition was determined as either strong or weak, taking into account the potential risks and benefits. The research committee included several factors into their considerations, including patient values and preferences, the magnitude of the effect, and their confidence in the available evidence. If the benefits were deemed to outweigh the risks for most individuals, the recommendation was categorized as strong. For all other cases, the recommendation was categorized as weak, indicating that individual clinical circumstances, values, and preferences should be taken into consideration.
The researchers concluded that CBMs may offer benefits in chronic pain management, but they also have potential risks and limitations. They emphasized the need for more high-quality research on the long-term effects and safety of CBMs for chronic pain and co-occurring conditions. The authors also suggested that patients and clinicians should work collaboratively to find the most appropriate and effective CBM for each individual case.
- Strong recommendations using moderate-quality evidence were made for the use of CBMs as monotherapy, replacement, or adjunct treatment for chronic pain, including central and/or peripheral neuropathic pain, to improve pain outcomes.
- Strong recommendations using low-quality evidence were made for the use of CBMs for managing muscular and neuropathic pain, HIV-related symptoms, muscle spasms, sleep disorders, and loss of appetite.
- Weak recommendations using low-quality evidence were made for CBMs for the management of chronic headache and migraine, nausea, and PTSD symptoms.
- Adjunctive CBM use with opioids was strongly recommended for the management of chronic pain in those experiencing unsatisfactory analgesia from opioid treatment using moderate-quality evidence.
- Dosing recommendations are concordant with previous guidelines following the concept of a low starting dose that is slowly titrated up to achieve optimal target symptom improvement with minimal off-target effects, including euphoria. The optimal therapeutic dose is the dose that allows the patient to reach treatment goals, including pain and symptom reduction and improvement in function, with minimal or no side effects. Patients do not need to feel “high” or impaired to have symptom improvement.
These guidelines provide updated practical recommendations for clinicians during a time period when approved conditions for CBMs vary substantially. The recommendations are based on a thorough systematic review with rigorous study selection and methods for data extraction, quality assessment, and data synthesis.
Stefan Broselid, Ph.D.
Editor-In-Chief, Aurea Care Medical Science Journal
Alan D. Bell, Caroline MacCallum, Shari Margolese, Zach Walsh, Patrick Wright, Paul J. Daeninck, Enrico Mandarino, Gary Lacasse, Jagpaul Kaur Deol, Lauren de Freitas, Michelle St. Pierre, Lynne Belle-Isle, Marilou Gagnon, Sian Bevan, Tatiana Sanchez, Stephanie Arlt, Max Monahan-Ellison, James O’Hara, Michael Boivin, Cecilia Costiniuk, External Review Panel, Nancy Chow, Dr. Rob Sealey, and Dr. Lynda Balneaves. Clinical Practice Guidelines for Cannabis and Cannabinoid-Based Medicines in the Management of Chronic Pain and Co-Occurring Conditions. Cannabis and Cannabinoid Research [Internet]. Ahead of print [cited 2023 Mar 31]. Available from: http://doi.org/10.1089/can.2021.0156