Chronic pain affects millions of Americans and ranges in its origin and severity. Alternative medicine as a means for pain management has become increasingly popular in the Western world. One source of which is the Cannabis plant, which has been cultivated and used for medicinal purposes since ancient times (Shannon, Lewis, Lee, & Hughes, 2019). While the Cannabis plant contains more than 80 different chemicals, known as cannabinoids, the two most abundant are tetrahydrocannabinol (THC) and cannabidiol (CBD). The former of which is known for its psychoactive properties, whereas the latter is known for its non-psychoactive properties (Shannon et al., 2019).
As for the mechanism of action, cannabinoids are thought to inhibit the release of neurotransmitters and neuropeptides, activate descending inhibitory pain pathways, and reduce neural inflammation (Vuckovic, Srebro, Vujovic, Vucetic, & Prostran, 2018). Research conducted in rat models revealed significant reduction in joint swelling related to arthritis when applied topically (Hammell et al., 2016). Various CBD formulations have been tested in pre-clinical studies to have diverse medicinal properties, including anti-nausea, anti-inflammatory, and anti-anxiolytic (Pauli, Conroy, Vanden Heuvel, & Park, 2020). A 2020 paper presented data from 16 completed clinical trials involving CBD-based drugs, primarily Epidiolex (a 100 mg/mL tincture with less than 0.3% THC) and similar formulations (Pauli et al., 2020). Although the findings from these studies were mixed, there was clear symptom reduction for many participants, with suggestions for future research to determine how best to minimize adverse effects and optimize CBD-based formulations (Pauli et al., 2020).
A few other papers have explored the effects of CBD on anxiety, sleep, and neuropathic pain. The main findings from a 2019 study found decreased anxiety scores within the first month in 79.2% of patients, which remained throughout the duration of the study. Sleep scores also improved within the first month in 66.7% of patients, but fluctuated over time (Shannon et al., 2019). Furthermore, several studies have supported the idea that CBD induces an analgesic effect to suppress inflammation and reduce chronic pain (Russo, 2008; Vuckovic et al., 2018; Xiong et al., 2012). Regarding the safety and side effects of cannabinoids, the current literature suggests it has a favorable safety profile. While the majority of human studies performed have been for the treatment of epilepsy and psychotic disorders, the most commonly reported adverse effects include tiredness, diarrhea, and changes in appetite/weight (Iffland & Grotenhermen, 2017). Additionally, in comparison with other drugs, CBD has an overall better side effect profile, which could prove beneficial to those on several medications to treat chronic conditions (Iffland & Grotenhermen, 2017). With that being said, it is imperative more research is needed to determine an optimal dosage and formulation that yields therapeutic results with limited adverse effects.
References
Hammell, D. C., Zhang, L. P., Ma, F., Abshire, S. M., McIlwrath, S. L., Stinchcomb, A. L., & Westlund, K. N. (2016). Transdermal cannabidiol reduces inflammation and pain-related behaviours in a rat model of arthritis. Eur J Pain, 20(6), 936-948. doi:10.1002/ejp.818
Iffland, K., & Grotenhermen, F. (2017). An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies. Cannabis Cannabinoid Res, 2(1), 139-154. doi:10.1089/can.2016.0034
Pauli, C. S., Conroy, M., Vanden Heuvel, B. D., & Park, S. H. (2020). Cannabidiol Drugs Clinical Trial Outcomes and Adverse Effects. Front Pharmacol, 11, 63. doi:10.3389/fphar.2020.00063
Russo, E. B. (2008). Cannabinoids in the management of difficult to treat pain. Ther Clinical Risk Management. doi:10.2147/tcrm.s1928
Shannon, S., Lewis, N., Lee, H., & Hughes, S. (2019). Cannabidiol in Anxiety and Sleep: A Large Case Series. Perm J, 23, 18-041. doi:10.7812/TPP/18-041
Vuckovic, S., Srebro, D., Vujovic, K. S., Vucetic, C., & Prostran, M. (2018). Cannabinoids and Pain: New Insights From Old Molecules. Front Pharmacol, 9, 1259. doi:10.3389/fphar.2018.01259
Xiong, W., Cui, T., Cheng, K., Yang, F., Chen, S. R., Willenbring, D., . . . Zhang, L. (2012). Cannabinoids suppress inflammatory and neuropathic pain by targeting alpha3 glycine receptors. J Exp Med, 209(6), 1121-1134. doi:10.1084/jem.20120242
