“Mechanical allodynia, the pain caused by innocuous tactile stimuli, is a hallmark symptom of neuropathic pain that is often resistant to currently available treatments.
Cannabinoids are widely used for pain management; however, their therapeutic mechanisms for neuropathic mechanical allodynia remain unclear.
Using transgenic rats that enable to optogenetically stimulate touch-sensing Aβ fibers in the skin, we found that the intrathecal administration of the synthetic cannabinoid, WIN 55,212-2, alleviated the Aβ fiber-derived neuropathic allodynia. Furthermore, we injected adeno-associated virus vectors incorporating the rat cannabinoid receptor 1 (CB1 receptor) (encoded by Cnr1) promoter and tdTomato or short hairpin RNA targeting the CB1 receptor into the spinal dorsal horn (SDH) and demonstrated that the conditional knockdown of CB1 receptors in Cnr1+ SDH neurons attenuates the anti-allodynic effects of intrathecally administered WIN 55,212-2. Electrophysiological analysis revealed that Cnr1+ SDH neurons received excitatory synaptic inputs from the primary afferent Aβ fibers.
Collectively, our results suggest that the CB1 receptors in Cnr1+ SDH neurons are molecular and cellular targets of intrathecal WIN 55,212-2 to alleviate neuropathic allodynia.”
“WIN 55,212-2 is a chemical described as an aminoalkylindole derivative, which produces effects similar to those of cannabinoids such as tetrahydrocannabinol (THC) “
“Many medical conditions are accompanied by severe pain. Acute pain refers to the experience of pain that lasts for only a few hours, whereas chronic pain is the ongoing emergence of pain signals over an extended period.
Since ancient times, cannabis has been utilized for medical purposes.
This article demonstrates the medicinal importance of cannabinoids through their analgesic and anti-inflammatory activities. Additionally, the mechanisms of cannabinoid-induced analgesia have been interpreted via preclinical investigations in animals. Cannabinoid extracts were formulated into gel and cream at concentrations of 2.5% and 5%.
The cannabis cream showed the highest analgesic activity at 5% compared to methyl salicylate as a control. Moreover, cannabis gel produced a comparable anti-inflammatory effect at 5% against the standard diclofenac sodium.
Molecular docking studies of all cannabinoids were performed to understand their modes of interaction and binding affinities with the cyclooxygenase II receptor. Additionally, molecular dynamics simulation studies were conducted for for both the ligand-free and cannabidiol-bound cyclooxygenase II to validate the in vivo and molecular docking results. During simulations, the stability of the protein was analyzed using root-mean-square deviation and root-mean-square fluctuation. The study of trajectories of the ligand-free and ligand-bound proteins was assessed using radius of gyration and solvent accessible surface area. Molecular mechanics/generalized Born surface area was used to evaluate the free energies of ligand binding. Dynamic cross-correlation matrix, principal component analysis and free energy landscape characterized the conformational changes and relative energies of them, which shows the existence of two metastable conformations in cyclooxygenase II, one of which is possibly the native state with catalytic activity.
In conclusion, the data from this study support the use of medicinal cannabis in the management of pain. To mitigate the suffering of patients experiencing extreme pain, the rational use of cannabis-based drugs merits significant consideration.”
“Background: Our objective was to provide an overview of the currently available scientific and clinical data supporting the use of Cannabis and Cannabis-derived products for the treatment of chronic pain disorders. We also provide information for researchers, clinicians, and patients to be better informed and understand the approach behind the recommendation of Cannabis as a potential adjuvant in the treatment/control of chronic pain. Cannabis and its bioactive compounds have sparked interest in the field of pain treatment in spite of its controversial history and status as a controlled substance in many countries. With the increase in chronic pain, physicians and patients have started to look at alternative ways to treat pain aside from traditional treatments. One alternative is the use of cannabis to reduce/treat chronic pain disorders based on anecdotal accounts and the function of its phytocannabinoids. The two main cannabinoids in cannabis, tetrahydrocannabinol (THC) and cannabidiol, act on CB1 and CB2 receptors (in addition to several additional receptors). It is through these pleiotropic receptor interactions that these compounds elicit their biological function including the reduction of chronic pain. In this narrative review, we included the most recent evidence supporting the use of cannabis in the treatment of chronic pain disorders including chronic neuropathic pain, cancer-induced neuropathic pain, chronic musculoskeletal pain, and chronic headaches and migraines.
Summary: Evidence suggests that cannabis and cannabinoids have an analgesic effect that arises from a combination of compounds and various receptor systems. These effects may be maximized with the use of a combination of cannabinoids. At the same time, the combination of cannabinoids helps minimize the undesirable side effects of some cannabinoids such as the psychoactivity of THC. With these findings, further research is necessary to assess the analgesic properties of other cannabinoids like cannabichromene and cannabigerol and their contributions to the reduction of pain.”
“Cannabis sativa L. has been used as a medicinal remedy for thousands of years. It has gone through multiple periods of acceptance, dismissal/rejection, reacceptance, illegality and, most recently, rediscovery of its potential to address chronic medical conditions. In the last few decades, its recreational use has received growing acceptance, while its medical use has been encouraged in multiple jurisdictions. Most modern research has focused on the phytocannabinoids produced by the plant which have been found to help minimize chronic neuropathic pain and mitigate other disorders including seizure conditions (e.g., Lennox-Gastaut and Dravet syndromes) and spasticity in MS. This review has provided scientific evidence supporting the use of cannabis as an adjuvant in the treatment of chronic pain which could also lead pain reduction to the point of minimizing other pharmacological treatments.”
“Ethnopharmacological relevance: Cannabis sativa has been widely used in traditional medicine for its therapeutic properties. However, in Morocco, the ethnobotanical applications of Cannabis sativa, especially its essential oils, are underexplored. This study investigates, for the first time, the effects of Moroccan Cannabis sativa essential oil on peripheral neuropathic pain.
Materials and methods: Peripheral neuropathic pain was induced in mice through sciatic nerve injury. The mice were treated daily with cannabis essential oil for 21 days. Behavioral tests were conducted on days 1, 7, 14, and 21 to evaluate thermal, mechanical, and cold sensitivity. The essential oil’s chemical composition was analyzed using gas chromatography-mass spectrometry (GC/MS).
Results: The main constituents of the essential oil were (E)-caryophyllene (41.59%) and α-humulene (14%). Daily treatment with the essential oil significantly reduced pain sensitivity and improved functional and histological recovery over time. These effects are linked to the activity of the dominant terpenoids in the oil.
Conclusion: Moroccan Cannabis sativa essential oil shows significant therapeutic potential for managing peripheral neuropathic pain. By enhancing recovery and alleviating pain symptoms, it offers a promising alternative for treating chronic pain caused by nerve injuries.”
“A multitude of recent studies have explored the broad biological properties of cannabis. Extracts from Cannabis sativa have demonstrated antimicrobial, anti-inflammatory, antinociceptive, and potent antioxidant activities.”
“This study examined the analgesic effects of terpenes found in Cannabis sativa essential oil on neuropathy. The results showed that chronic administration of these bioactive terpenes, specifically β-caryophyllene, α-humulene, and caryophyllene oxide, significantly increased pain sensitivity and response time in mice with neuropathy. Although morphine and THC-based treatments are commonly used to relieve neuropathic pain, these terpenes may offer a promising alternative with limited side effects. Clinical research has demonstrated the efficacy of cannabis-based treatments, leading several pain societies to recommend them for neuropathy management. “
“Neuropathic pain (NP) is a complex and debilitating condition that is often refractory to currently available analgesic medications.
Cannabis sativa extract (CSE) has been reported to exhibit analgesic properties across various pain models; however, the underlying mechanisms of action are not fully understood.
This study aimed to investigate the involvement of the cannabinoid CB2 receptor in mediating the analgesic effects of CSE in a rat model of NP, where NP was induced in male Wistar rats through chronic constriction injury (CCI) of the sciatic nerve.
Rats were randomly allocated into four groups: (1) Sham + vehicle, (2) CCI + vehicle, (3) CCI + CSE, and (4) CCI + CSE + AM630 (a CB2 receptor antagonist). CSE was administered intraperitoneally at a dosage of 30mg/kg once daily for 7 days, starting from day 7 to day 13 post-CCI surgery. To assess the involvement of the CB2 receptor, 7µg of AM630 was administered intrathecally to the rats in group 4, 30minutes before the CSE injections. Mechanical allodynia and thermal hyperalgesia were assessed using the von Frey filament and hot plate tests, respectively, at baseline (day 0) and on days 3, 7, 10, and 14 after surgery. Additionally, at the end of the study period (day 14), the expression level of Iba1 and GFAP genes was quantified in the lumbar enlargement tissues using real-time PCR.
The results demonstrated that CCI surgery induced mechanical allodynia and thermal hyperalgesia, along with the upregulation of Iba1 and GFAP genes in the vehicle-treated CCI group. Treatment with CSE significantly mitigated both allodynia and hyperalgesia and downregulated the expression of Iba1 and GFAP genes compared to the CCI + vehicle group. Furthermore, the administration of the CB2 receptor antagonist AM630 not only robustly blocked the antinociceptive effects of CSE but also reversed the significant downregulation of Iba1 and GFAP gene expression in the lumbar enlargement tissues.
These findings highlight the novel role of the CB2 receptor in mediating the analgesic effects of CSE, providing new insights into the potential therapeutic mechanisms of CSE in neuropathic pain management.”
“In summary, this study provides evidence that CSE exerts analgesic and anti-inflammatory effects in NP through CB2 receptor activation. These findings contribute to the growing body of research supporting cannabinoids as potential therapeutic agents for NP management.”
“Reviews of the effectiveness of medicinal cannabis for chronic pain vary in their conclusions. IASP has identified that a key missing evidence in this debate is data from observational cohort studies, analyzed with comparative effectiveness methods.
In a medically supervised context to the use of marijuana for chronic pain, we identified 440 patients certified for medical marijuana by pain specialists in a single healthcare system. They were characterized by a battery of patient-reported outcomes stored electronically in the University of Pittsburgh Patient Outcomes Repository for Treatment (PORT).
At 3 months, 38.6% were responders, based on clinically meaningful improvements in pain, function, or global impression of change, and maintained this response at 6 months. In the 157 patients who were coprescribed opioids, at 6 months there was a mean 39.3% decrease in morphine milligram equivalents (P < 0.05 for the difference vs baseline).
In addition, 8114 patients treated in the same pain clinics with prescription pain medications instead (nonopioid or opioid) during the same timeframe were selected from PORT as a control group for comparison. They had a 34.9% rate of response at 3 months. Using the causal inference method of stratified modeling, logistic regression revealed an odds ratio of 2.6 in favor of medical marijuana vs medication treatment (P < 0.01). Potential harms data were not available in the PORT registry.
Medical marijuana was comparatively more effective than prescription medications for the treatment of chronic pain at 3 months, although the populations compared were slightly different.”
“Cannabis use among women who experience chronic pain is on the rise in the United States. However, little is known about women’s motives and preferences for cannabis administration. The purpose of this study was to characterize cannabis use among women with chronic pain.
This study examined self-reported forms of cannabis administration and preferred source of cannabis, frequency and quantity of use, and self-reported side effects, and type, level, and intensity of chronic pain among adult women in the United States. This study also compared women who use cannabis for chronic pain and those who do not across the level of chronic pain, length of chronic pain, and the number of types of chronic pain experienced.
Participants showed a significant preference (60%) for using recreational cannabis to treat chronic pain but reported that medical cannabis was more effective. For participants who preferred medical cannabis 24.3% reported daily use, as compared to only 7.8% of recreational cannabis users. Smoking was the most common form of administration (62.1%), followed by edibles (25.3%), vaporizing in any form (7.4%), tinctures and concentrates (3.2%), and topicals (2.1%). Participants reported using 1-6 different forms of cannabis administration. Those who preferred smoking were significantly likely to use all other forms of administration. However, those who preferred alternatives to smoking were significantly likely to use all forms of administration except for smoking. Medical cannabis users preferred to obtain cannabis from a dispensary, while recreational users preferred to obtain cannabis from unlicensed sources.
Additionally, participants who used cannabis for chronic pain reported a 74% reduction in past 30-day opioid use.
Future research is needed to investigate the health effects associated with single and combined forms of cannabis administration for women with chronic pain. Results can inform educational and intervention programs, treatment development, content regulation of products, policy formation, women’s health research, and public health guidelines.”
“Background: Cannabinoids are considered a therapeutic option to patients suffering from treatment refractory chronic pain (TRCP) insufficiently relieved by conventional analgesics or experiencing intolerable adverse events (AEs) from those. This study aimed to explore safety and effectiveness of oral cannabinoids among patients with TRCP.
Methods: A retrospective study was conducted among Danish patients with TRCP being prescribed oral cannabinoids. Data on AEs and changes in pain intensity by numeric rating scale (NRS) before and after initiation of oral cannabinoid therapy were analysed.
Results: Among 826 eligible patients ≥18 years old, 529 (64%) were included for data analysis at first follow-up (F/U1) (median 56 days from baseline) and 214 (26%) for second follow-up (F/U2) (median 126 days from F/U1). Mean age was 60 ± 15.9 years and 70% were females. AEs were in general reported mild to moderate by 42% of patients at F/U1 and 34% at F/U2. AEs were mainly related to gastrointestinal (F/U1: 17% and F/U2: 13%) and nervous system disorders (F/U1: 14% and F/U2: 11%). Reduction in NRS was significantly different at both follow-up consultations compared with baseline (<0.0001). Clinically relevant pain reduction (NRS ≥30%) was reported by 17% at F/U1 and 10% of patients at F/U2 in intention-to-treat analysis whereas the figures were 32% and 45% respectively, in per-protocol analysis.
Conclusion: Oral cannabinoid therapy seems to be safe and mildly effective in patients with TRCP. Randomized controlled trials with focus on comparable pain characteristics in diagnostical homogenous patient subgroups are needed for further improvement of evidence level for relief of chronic pain using oral cannabinoids.
Significance: The findings in this retrospective study conducted in a real-world clinical setting suggest a favourable safety profile of cannabinoids. Moreover, one-sixth (intention-to-treat) and one-third (per-protocol) of patients with chronic pain refractory to conventional analgesics, or experiencing intolerable adverse effects, benefited significantly from therapy with oral cannabinoid regimens. Combination of THC and CBD seems overall more effective than cannabinoid monotherapy. Conduction of randomized controlled trials investigating safety and efficacy of cannabinoid therapy to diagnosis specific patient subgroups with comparable clinical and pathophysiological chronic pain characteristics is warranted, hence contributing further to the process of clinical evidence clarification currently in progress.”
“In conclusion, oral cannabinoid therapy in general appears to be safe and effective for relief of chronic pain in some patients, including a subset of patients with cancer-related pain (9%), not responding adequately to conventional treatment regimens or experiencing intolerable AEs. Moreover, beneficial effects on sleep and QoL were reported by the patients receiving oral cannabinoid therapy, although the assessment was not performed in a validated manner. Hence, our study confirms previously reported findings related to patients with chronic pain receiving oral cannabinoid therapy and in that way the study contributes further to the evidence pyramid at the level of observational studies. “
“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.”
“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.”
“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.”
