The Effect of Medical Cannabis on Pain Level and Quality of Sleep among Rheumatology Clinic Outpatients

Medical cannabis and its efficacy/effectiveness on the management of osteoarthritis pain and function

OBJECTIVE

Despite pharmacological treatments for osteoarthritis (OA), more individuals are choosing medical cannabis for OA symptom management and for mitigating opioid prescriptions for OA. This systematic review examines the global evidence of medical cannabis use on OA pain and function.

METHODS

The search was completed in MEDLINE (PubMed), Embase, and CINAHL within the past 10 years (2012-2022). We limited the search to English language articles. We did not include grey literature or case studies. Participant demographics included all adult individuals with OA who were using medical cannabis for OA. Study quality and risk of bias were evaluated using the Grading of Recommendations, Assessment, Development and Evaluations framework; and the Risk of Bias in Non-randomized Studies of Interventions tool. We used a narrative synthesis approach.

RESULTS

Overall, 7 studies were included: 2 randomized controlled trials (RCT) and 5 observational studies. Only 1 of the 2 RCTs reported improvements in pain for cannabis users. All 5 observational studies reported an improvement in pain levels, reduction of opioid use, and/or improvement in overall OA function. Despite high risk of bias ratings and low study quality, the consensus across studies was that medical cannabis use was effective for a subgroup of individuals suffering from OA pain.

CONCLUSIONS

There is low quality evidence to support medical cannabis use as a substitute for primary pharmacological treatment of OA. However, this does not negate the observations that medical cannabis may provide therapeutic relief for a subset of patients.

SYSTEMATIC REVIEW PROPSERO REGISTRATION

CRD42022354026.

The Underlying Mechanisms of Sleep Deprivation Exacerbating Neuropathic Pain

Pain disrupts sleep, and sleep deprivation or interference can alter pain perception in animals and humans, for example by increasing sensitivity to pain. However, the mechanism by which sleep affects neuropathic pain remains unclear. In this review, we discuss the available evidence from the epidemiologic, clinical, and human, as well as laboratory studies. In previous studies, we have found that sleep deprivation affects various injurious systems, including opioids, dopaminergic, immune, orexins, hypothalamic-pituitary-adrenal axis, and adenosine. At the same time, these systems play a crucial role in neuropathic pain regulation. In the complex interactions between these neurobiological systems, there may be potential regulatory pathways through which sleep deprivation amplifies neuropathic pain. Because of the impact sleep problems and neuropathic pain can have on the patients' quality of life, studying the link between sleep and neuropathic pain is important for neuropathic pain prevention and public health.

Impact of Δ9-Tetrahydrocannabinol on Rheumatoid Arthritis Synovial Fibroblasts Alone and in Co-Culture with Peripheral Blood Mononuclear Cells

δ9-Tetrahydrocannabinol (THC) has demonstrated anti-inflammatory effects in animal models of arthritis, but its mechanism of action and cellular targets are still unclear. The purpose of this study is to elucidate the effects of THC (0.1-25 µM) on synovial fibroblasts from patients with rheumatoid arthritis (RASF) and peripheral blood mononuclear cells (PBMC) from healthy donors in respect to proliferation, calcium mobilization, drug uptake, cytokine and immunoglobulin production. Intracellular calcium and drug uptake were determined by fluorescent dyes Cal-520 and PoPo3, respectively. Cytokine and immunoglobulin production were evaluated by ELISA. Cannabinoid receptors 1 and 2 (CB1 and CB2) were detected by flow cytometry. RASF express CB1 and CB2 and the latter was increased by tumor necrosis factor (TNF). In RASF, THC (≥5 µM) increased intracellular calcium levels/PoPo3 uptake in a TRPA1-dependent manner and reduced interleukin-8 (IL-8) and matrix metalloprotease 3 (MMP-3) production at high concentrations (25 µM). Proliferation was slightly enhanced at intermediate THC concentrations (1-10 µM) but was completely abrogated at 25 µM. In PBMC alone, THC decreased interleukin-10 (IL-10) production and increased immunoglobulin G (IgG). In PBMC/RASF co-culture, THC decreased TNF production when cells were stimulated with interferon-γ (IFN-γ) or CpG. THC provides pro- and anti-inflammatory effects in RASF and PBMC. This is dependent on the activating stimulus and concentration of THC. Therefore, THC might be used to treat inflammation in RA but it might need titrating to determine the effective concentration.