Category Archives: Chronic Inflammatory and Neuropathic Pain

The Use of Cannabinoids in the Treatment of Peripheral Neuropathy and Neuropathic Pain: A Systematic Review

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“Purpose: Peripheral neuropathies are commonly occurring conditions that are chronic and debilitating for patients. Established nonsurgical treatments have yielded mixed and patient-dependent results. Although cannabinoids have demonstrated efficacy as a treatment for central neuropathic pain, the therapeutic potential of cannabis-based medications for the management of peripheral neuropathic pain caused by nerve injury, trauma, and other noncompressive etiologies has yet to be definitively established. This study aims to determine whether cannabinoids are a potentially effective treatment for pain and symptoms associated with peripheral neuropathy.

Methods: A systematic search was conducted by two independent reviewers across PubMed, Cochrane, Ovid Medline, and CINAHL to identify studies in accordance with the predetermined inclusion/exclusion criteria. Information regarding study design, medication, dosage, effect on neuropathic pain, and other related outcomes was extracted. Meta-analysis of pain scores was performed for seven studies, and descriptive statistics were used to summarize other study findings as appropriate.

Results: Of the 927 studies identified, 14 randomized controlled trials were included. Thirteen of 14 studies (79%) observed a statistically significant decrease in neuropathic pain score following treatment with a cannabinoid. Meta-analysis yielded a mean difference of -0.67 [-0.89, -0.45]) on a 0-10 scale compared with placebo. Improvements in secondary outcomes such as sleep, sensory symptoms, and quality of life were observed.

Conclusions: Our analysis of the literature shows that cannabis-based medicines may be effective in treating the pain and symptoms of peripheral neuropathy. These findings suggest the applicability of cannabis-based medicines for peripheral neuropathy.”

https://pubmed.ncbi.nlm.nih.gov/39570218/

https://www.jhandsurg.org/article/S0363-5023(24)00474-X/abstract

UK medical cannabis registry: A clinical outcome analysis of medical cannabis therapy in chronic pain patients with and without co-morbid sleep impairment

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“Introduction: Chronic pain (CP) affects 35.0%-51.3% of the UK population, with 67%-88% reporting sleep disturbances. Cannabis-based medicinal products (CBMPs) have shown therapeutic potential in managing CP. Evidence suggests poor sleep worsens pain perception; therefore, this study aimed to assess patient-reported outcome measures (PROMs) following CBMP treatment in CP patients with and without co-morbid sleep impairment.

Methods: A prospective cohort study of CP patients from the UK Medical Cannabis Registry was conducted. Participants were separated by baseline single-item sleep quality scale (SQS) score into sleep impaired (SQS ≤3) and unimpaired (SQS ≥4) cohorts. The primary outcome assessed changes in PROMs from baseline to 1-, 3-, 6-, and 12-months. Participants completed the following: SQS, General Anxiety Disorder-7, EQ-5D-5L, Brief Pain Inventory (BPI), and Short-Form McGill Pain Questionnaire-2. Significance was defined as p < 0.050.

Results: 1139 participants met the inclusion criteria (sleep impaired: n = 517, 45.4%; sleep unimpaired: n = 622, 54.61%). The sleep impaired cohort showed improvements in all PROMs at each follow-up (p < 0.010). The sleep unimpaired cohort showed similar results (p < 0.050), except in SQS and ED-5Q-5L: self-care and anxiety/depression scores (p > 0.050). However, the sleep impaired cohort observed greater improvements in BPI pain severity (p < 0.050) and SQS (p < 0.001) than the sleep unimpaired cohort at all follow-ups. 2817 adverse events were self-reported between both cohorts (p = 0.197).

Discussion: These findings align with literature that shows associated improvements in pain outcomes following CBMP administration. Sleep impaired individuals were more likely to experience greater pain severity improvements. However, this was not confirmed on multivariate logistic regression analysis and instead may be confounded by baseline pain severity.

Conclusion: Whilst these results show promise for the effects of CBMPs on CP, they must be examined within the limitations of the study design. These findings provide further evidence to support the design of subsequent randomized controlled trials to verify causality between CBMPs and pain outcomes.”

https://pubmed.ncbi.nlm.nih.gov/39545361/

“The results of this observational cohort study suggest an association between CBMP treatment and improvement in pain-specific and HRQoL PROMs in CP patients with and without co-morbid sleep impairment. Notably, those with co-morbid sleep impairment were associated with greater improvements in BPI pain severity, SQS, and PGIC than those without. However, this finding was not confirmed on multivariate analysis. Reported sleep quality did improve across the cohort from baseline, and when present was also associated with improvements in pain severity, suggesting that the effects of CBMPs on sleep may provide additional benefits for individuals with chronic pain beyond affecting the transmission of nociceptive signals. At the onset of treatment, however, other variables may be better prognostic markers for response to CBMP treatment, such as severe pain or anxiety at baseline. With respect to clinical significance, 44.10% report an improvement in the sleep impaired cohort at 1-months, declining to 24.56% at 12-months. Despite being limited by its observational design, the present study can be used to inform future RCTs, in addition to current clinical practice.”

https://onlinelibrary.wiley.com/doi/10.1111/papr.13438

Changes in Pain and Mental Health Symptoms Associated with Prescribed Medicinal Cannabis Use: A One-Year Longitudinal Study

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“Chronic pain and mental health issues like depression and anxiety significantly contribute to disease burden in Western countries.

While cannabinoids are suggested to have analgesic, anxiolytic and antidepressant properties, evidence, especially for long-term use, is inconclusive. This 12-month observational study evaluated the effects of prescribed medicinal cannabis for 96 patients suffering from pain, as well as sleep disturbances, depression and anxiety. Treatment outcomes for pain, depression, anxiety and sleep problems were assessed at 3, 6, and 12 months using validated instruments.

Significant reductions were observed in pain scores and the interference of pain on daily functions, alongside improvements in mental health and sleep. Many patients reported notable improvements in pain severity and reduced use of pain medications in the first 6 months, with a decline at 12 months. Additionally, sustained improvements in depression, anxiety, stress and sleep were observed, with about half reporting substantial improvement. Adverse effects were common but mostly mild or moderate, most commonly dry mouth and sleepiness.

These results show that prescribed medicinal cannabis treatment is associated with improvements in chronic pain and mental health symptoms, such as depression, anxiety and stress. However, findings also suggest reduced effectiveness with longer-term use, emphasizing the need for additional research.”

https://pubmed.ncbi.nlm.nih.gov/39432717/

“Cannabis is a plant that has been used for thousands of years as a traditional medicine to treat various medical ailments, including pain.

Overall, we found that the use of medicinal cannabis was associated with reduced pain during the first 6 months and improved mental well-being over 12 months. Patients reported not only less pain but also experienced reduced interference from pain in their daily functions. Furthermore, they reported decreased use of pain medications and a large proportion felt that their pain symptoms had significantly improved, as reflected in their reported changes in the severity of pain.”

https://www.tandfonline.com/doi/full/10.1080/15360288.2024.2414898

An early economic analysis of medical cannabis for the treatment of chronic pain

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“Background: Cannabis-based medicinal products (CBMPs) are increasingly demonstrating effectiveness in treating a wide range of conditions, with a relatively high safety profile in clinical usage compared to other prescription pain medications and few contraindications. Consultation and other prescription-related costs are, at present, higher for CBMPs than for some other treatment options, leading to some concern around wider prescribing.

Research design and methods: An early cost-effectiveness model was developed to estimate the impact of prescribing CBMPs alone and/or in addition to analgesics, physiotherapy, and cognitive behavioral therapy for chronic pain in the UK for 1 year.

Results: Due to their comparative effectiveness, CBMPs were found to be cost saving. Various scenarios were model tested; in all scenarios where CBMPs decrease pain-level states, less resource use is required. Increased efficacy of 5% was conservatively assumed based on current Real-World Evidence. In this scenario, CBMPs were significantly more cost-effective, and as costs relating to the prescribing of these continue to fall, relative savings are predicted to increase.

Conclusion: These findings highlight the substantial cost saving that CBMPs may represent for the treatment of chronic pain patients, and the benefits for healthcare providers as a treatment for this often hard-to-treat population.”

https://pubmed.ncbi.nlm.nih.gov/39415537/

https://www.tandfonline.com/doi/full/10.1080/14737167.2024.2412248

Cannabinoids shift the basal ganglia miRNA m6A methylation profile towards an anti-inflammatory phenotype in SIV-infected Rhesus macaques

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“Epitranscriptomic modifications modulate diverse biological processes, such as regulation of gene expression, abundance, location and function. In particular, N6-methyladenosine (m6A) methylation has been shown to regulate various disease processes, including cancer and inflammation. While there is evidence that m6A modification is functionally relevant in neural development and differentiation, the role of m6A modification in HIV neuropathogenesis is unknown.

Here, we identified direct m6A modifications in miRNAs from BG tissues of Rhesus Monkeys (RMs) that were either vehicle-treated uninfected (VEH), SIV-infected combination anti-retroviral therapy (cART) treated (VEH/SIV/cART), or THC:CBD treated VEH/SIV/cART (THC:CBD/SIV/cART) RMs.

We detected m6A modifications across all BG tissues. SIV infection promoted an overall hypomethylated m6A profile. While the overall hypomethylated m6A profile was not significantly impacted by THC:CBD treatment, specific miRNAs, particularly those predicted to target proinflammatory genes showed markedly reduced m6A methylation levels compared to the VEH treated RMs. Additionally, we found that specific BG tissue miRNAs bearing m6A epi-transcriptomic marks were also transferred to BG-derived extracellular vesicles (EVs). Mechanistically, we identified the DRACH motif of the seed region of miR-194-5p to be significantly m6A hypomethylated, which was predicted to directly target STAT1, an important interferon-activated transcription factor known to drive neuroinflammation, in diseases ranging from Alzheimer to Parkinson and Huntington disease.

Notably, THC:CBD treatments significantly reduced m6A methylation of 43 miRNA species directly involved in regulating CNS network genes, thus providing a possible mechanist explanation on the beneficial effects of THC:CBD treatments noted in several disease involving neuroinflammation.

Our findings also underscore the need for investigating the qualitative, posttranscriptional modification changes in the RNA profiles along with the more traditional, qualitative alterations in pathological conditions or after various treatment regimens.”

https://pubmed.ncbi.nlm.nih.gov/39416016/

https://www.biorxiv.org/content/10.1101/2024.10.11.614514v1

Edible cannabis for chronic low back pain: associations with pain, mood, and intoxication

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“Introduction: Cannabis, commonly known for both therapeutic and intoxicating effects, is gaining accessibility on legal markets and traction as a potential alternative therapy for pain mediation, particularly in those suffering from chronic low back pain. However, the effectiveness in this population of legal market forms of cannabis, particularly commonly used edibles, is unknown.

Methods: Therefore, this study utilized a naturalistic prospective design where participants with chronic low back pain with intentions to initiate cannabis use for treatment were recruited and self-selected edible cannabis products containing varying amounts of delta- 9 tetrahydrocannabinol (THC) and cannabidiol (CBD). Products were categorized as CBD-dominant, THC-dominant, or combined THC and CBD (THC + CBD).

Results: 249 participants [140 female (56.62%), mean (SD) age of 46.30 (16.02), 90% White] were tracked over 2 weeks of ad libitum use and assessed during a naturalistic acute cannabis administration session on changes in pain, mood, and subjective drug effects. During acute administration, a significant correlation between THC dose and short-term pain relief was found, suggesting that higher THC doses were associated with greater pain reduction (p < .05). In addition, THC was associated with higher levels of subjective cannabis drug effects (p < .001), regardless of whether CBD was also in the edible product. Acute CBD dose was primarily associated with short-term tension relief (p < .05); however, there were no associations between CBD dose and acute pain. Over the 2-week ad libitum administration period results suggested pain reductions across participants using all forms of cannabis. However, trends suggested that more frequent use of CBD-dominant edible cannabis may be associated with greater reductions in perceived pain over the 2-week observation period (p = .07).

Discussion: These findings support the short-term analgesic effects of THC and anxiolytic effects of CBD and further suggest that orally-administered THC and CBD should continue to be evaluated for the potential to provide both acute and extended relief from chronic low back pain.”

https://pubmed.ncbi.nlm.nih.gov/39380911/

“In this naturalistic observational study, it was found that the use of edible cannabinoid products significantly reduced chronic pain in extended and acute use models. More specifically, THC dose was associated with the greatest decrease in pain during the acute use session. Further, there was signal that more frequent use of a CBD-dominant product may provide stronger relief over a 2-week ad libitum use period.

These results indicate that edible cannabis may be a safe and suitable alternative pain therapy for those looking to substitute more traditional pain medications.”

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1464005/full

Identification of the TRPA1 Cannabinoid-Binding Site

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“Chronic pain accounts for nearly two-thirds of conditions eligible for medical cannabis licenses, yet the mechanisms underlying cannabis-induced analgesia remain poorly understood.

The principal phytocannabinoids, the psychoactive Δ9-tetrahydrocannabinol (THC) and non-psychoactive cannabidiol (CBD), exhibit comparable efficacy in pain management. Notably, THC functions as an agonist of cannabinoid receptor 1 (CB1), whereas CBD shows minimal activity on CB1 and CB2 receptors.

Elucidating the molecular targets through which phytocannabinoids modulate the pain system is required for advancing our understanding of the pain pathway and optimizing medical cannabis therapies.

Transient receptor potential ankyrin 1 (TRPA1), a pivotal chemosensor in the pain pathway, has been identified as a phytocannabinoid target. Unlike most TRPA1 activators, phytocannabinoid activation is not mediated through the electrophilic binding site, suggesting an alternative mechanism. Here, we identified the human TRPA1 channel cannabinoid-binding site (CBS) and demonstrated that mutations at residue Y840 abolished responses to both THC and CBD at saturating concentrations, indicating a shared primary binding site. Molecular modeling revealed distinct interactions of THC and CBD with the Y840 residue within the CBS. Additionally, CBD binds to the adjacent general anesthetic binding site at oversaturating concentrations.

Our findings define the CBS of TRPA1 as overlapping with and adjacent to binding sites for other allosteric activators, suggesting that TRPA1 possesses a highly adaptable domain for binding non-electrophilic activators. This underscores its unique role as a chemosensor in the pain pathway. Furthermore, our results provide new insights into the molecular mechanisms of cannabinoid-induced analgesia and identify novel targets for pain management therapies.”

https://pubmed.ncbi.nlm.nih.gov/39368566/

https://www.sciencedirect.com/science/article/pii/S104366182400389X?via%3Dihub

Cannabis sativa L. Extract Alleviates Neuropathic Pain and Modulates CB1 and CB2 Receptor Expression in Rat

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“Introduction: Cannabis sativa L. (CSL) extract has pain-relieving potential due to its cannabinoid content, so the effects of two CSL extracts on alleviating neuropathic pain were investigated in vivo. Methods and groups: Male Wistar rats (n = 130) were divided into groups and received vincristine (0.1 mg/kg) and gabapentin (60 mg/kg) to induce and relieve neuropathic pain or CSL extracts (D and B). The mRNA and protein expression of the cannabinoid receptors type 1 and 2 (CB1R, CB2R) were evaluated in the cerebral cortex, hippocampus, and lymphocytes. Behavioural tests (Tail-Flick and von Frey) were performed on all animals.

Results: VK-induced neuropathic pain was accompanied by decreased CB1R protein level and CB2R mRNA expression in the cortex. Gabapentin relieved pain and increased CB1R protein levels in the hippocampus compared to the vincristine group. Hippocampus CB1R protein expression increased with the administration of extract D (10 mg/kg, 40 mg/kg) and extract B (7.5 mg/kg, 10 mg/kg) compared to VK group. In the cerebral cortex CSL decreased CB1R protein expression (10 mg/kg, 20 mg/kg, 40 mg/kg of extract B) and mRNA level (5 mg/kg, 7.5 mg/kg of extract B; 20 mg/kg of extract D) compared to the VK-group.CB2R protein expression increased in the hippocampus after treatment with extract B (7.5 mg/kg) compared to the VK-group. In the cerebral cortex extract B (10 mg/kg, 20 mg/kg) increased CB2R protein expression compared to VK-group.

Conclusion: Alterations in cannabinoid receptor expression do not fully account for the observed behavioural changes in rats. Therefore, additional signalling pathways may contribute to the initiation and transmission of neuropathic pain. The Cannabis extracts tested demonstrated antinociceptive effects comparable to gabapentin, highlighting the antinociceptive properties of Cannabis extracts for human use.”

https://pubmed.ncbi.nlm.nih.gov/39334832/

“Furthermore, both tested Cannabis sativa L. extracts demonstrated antinociceptive effects comparable to gabapentin, highlighting the potential medical value of Cannabis extracts for human use.”

https://www.mdpi.com/2218-273X/14/9/1065

Cannabinoids as a Natural Alternative for the Management of Neuropathic Pain: A Systematic Review of Randomized Placebo-Controlled Trials

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“Dysfunction or damage to the nervous system may develop into and result in a chronic pain condition known as neuropathic pain. Neuropathic pain is defined as the structural and functional alteration of the somatosensory component of the nervous system. The treatment of neuropathic pain is a complex endeavor, which often requires specialist care and intensive drug therapy. Recently, cannabinoids have emerged as an alternative and natural option for the treatment of chronic pain, with tetrahydrocannabinol (THC) and cannabidiol (CBD) being the most extensively studied neuroactive components. The therapeutic potential of cannabis remains largely underexplored, primarily due to its social stigma and the restrictions that are in place on its cultivation. The primary aim of this systematic review was to explore the therapeutic value of cannabinoids in the management of chronic pain and thus achieve an improved quality of life for those patients.

A systematic review of the literature published over the last two decades was performed using the following databases: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Turning research into practice (Trip), and Google Scholar. Studies that were completed and published between January 01, 2000 and August 31, 2024, in English language, were extracted and appraised. A combination of keywords and Boolean operators Cannabis OR Chronic Pain OR End of life OR Pain Management AND Drug therapy was employed for data extraction. The Cochrane risk-of-bias tool for randomized trials (RoB 2) was used for risk-of-bias assessment. The initial search resulted in 125282 articles; 86,781 of the articles were identified as duplicates and were removed from the primary analysis, and 38,501 abstracts were thus screened. Abstracts, case studies, reports, editorials, viewpoints, cross-sectional studies, cohort studies, case-control studies, case series, and letters to the editor/correspondence manuscripts (n =38,492) were furthermore excluded. Nine full-text articles were critically assessed and tested against the inclusion and exclusion criteria, and a further four articles were excluded with a total of five placebo-controlled randomized control studies being ultimately included in the final systematic review.

Compared to placebo, cannabinoids provided significant relief from chronic pain (33% vs 15%) as measured by the visual analog scale. The transdermal application of CBD led to a more pronounced reduction in sharp pain, according to the neuropathic pain scale. Minimal to no side effects were recorded, further highlighting the potential benefits of cannabinoids. 

The potential benefit of cannabinoids is that they are naturally derived drugs that have already been shown to have the potential to effectively decrease chronic pain with minimal side effects as compared to the standard drugs being used. The ability of cannabinoids to provide pain relief with minimal side effects and concurrently be a naturally derived product may potentially be a life-changing alternative that the pharmaceutical market is in dire need of.”

https://www.cureus.com/articles/297124-cannabinoids-as-a-natural-alternative-for-the-management-of-neuropathic-pain-a-systematic-review-of-randomized-placebo-controlled-trials#!/

The endocannabinoid system as a therapeutic target in neuropathic pain: a review

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“Introduction: This review highlights the critical role of the endocannabinoid system (ECS) in regulating neuropathic pain and explores the therapeutic potential of cannabinoids. Understanding the mechanisms of the ECS, including its receptors, endogenous ligands, and enzymatic routes, can lead to innovative treatments for chronic pain, offering more effective therapies for neuropathic conditions. This review bridges the gap between preclinical studies and clinical applications by emphasizing ECS modulation for better pain management outcomes.

Areas covered: A review mapped the existing literature on neuropathic pain and the effects of modulating the ECS using natural and synthetic cannabinoids. This analysis examined ECS components and their alterations in neuropathic pain, highlighting the peripheral, spinal, and supraspinal mechanisms. This review aimed to provide a thorough understanding of the therapeutic potential of cannabinoids in the management of neuropathic pain.

Expert opinion: Advances in cannabinoid research have shown significant potential for the management of chronic neuropathic pain. The study emphasizes the need for high-quality clinical trials and collaborative efforts among researchers, clinicians, and regulatory bodies to ensure safe and effective integration of cannabinoids into pain management protocols. Understanding the mechanisms and optimizing cannabinoid formulations and delivery methods are crucial for enhancing therapeutic outcomes.”

https://pubmed.ncbi.nlm.nih.gov/39317147/

“Research on the modulation of the endocannabinoid system in nervous tissue related to neuropathic pain reveals complex mechanisms of pain modulation. Dysregulation of the endocannabinoid system, microglial activation, and interactions between various signaling pathways contribute to the onset and persistence of neuropathic pain. Understanding these molecular and cellular processes is crucial for developing targeted therapies that leverage the endocannabinoid system to alleviate neuropathic pain.”

https://www.tandfonline.com/doi/full/10.1080/14728222.2024.2407824

“Smoked Cannabis Proven Effective In Treating Neuropathic Pain”

https://www.sciencedaily.com/releases/2007/10/071024141745.htm