Category Archives: Chronic Inflammatory and Neuropathic Pain

Endocannabinoid system modulation in acute, chronic, and neuropathic pain: reviewing experimental models, clinical evidence, and nanotechnology delivery

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“Chronic pain is highly prevalent and inadequately managed by current therapeutic strategies, which present significant limitations such as the development of tolerance, dependence, and cognitive impairment. Therefore, searching for new pain management strategies is an ultimate goal.

The endocannabinoid system (ECS), is a broad crucial regulatory network in central nervous system’s development and in modulating various physiological and cognitive functions. It comprises endogenous cannabinoids, cannabinoid receptors, and the enzymes governing cannabinoid production and breakdown.

Recently, cannabinoids, particularly medical cannabis, have garnered renewed interest for their possibilities in treating different medical conditions, including chronic pain.

Although the risk of lethal overdose is negligible, the prevalence of non-serious adverse effects is significant and requires careful clinical consideration. Currently, there is a paucity of sufficient efficacy and long-term safety data to fully support the systematic use of medical cannabis for chronic non-malignant pain conditions.

Further research is crucial to unlock the future potential of these approaches and to delineate essential directions for exploring the ECS and its role in pain management. Advances in nanotechnology have enabled novel delivery platforms that address key limitations of cannabinoid-based therapies.

Nanocarriers, including lipid and polymeric nanoparticles, nanoemulsions, and self-emulsifying systems, can improve cannabinoid solubility, stability, bioavailability, and targeted delivery. Through controlled release and site-specific targeting, these systems hold promise for enhancing the analgesic efficacy and safety of cannabinoid therapeutics.”

https://pubmed.ncbi.nlm.nih.gov/42154330

https://link.springer.com/article/10.1007/s11011-026-01862-4

Medical Cannabis as an Opiate Alternative: A Prospective Observational Cohort Study

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“Opioid use for chronic pain has contributed to an epidemic of overdoses and deaths in the United States.

Some clinical studies suggest that medical cannabis may help alleviate pain and improve quality of life. However, cost can be a barrier to patients accessing medical cannabis.

This is the first prospective observational study evaluating medical cannabis as an alternative to opioids in a setting where cost was removed as a major barrier.

Methods: Twenty-nine patients were recruited from a university-based outpatient chronic pain clinic. Each patient underwent monthly pain assessments using the Numeric Pain Rating Scale (NRS). Daily opioid use, measured in morphine milligram equivalents (MMEs), was recorded and monitored over five months. Pain-related quality of life was assessed using the SF-36 Health Survey at baseline, and again at two and five months.

Results: Daily opioid use decreased from baseline to one month (from 46.8 MMEs to 16.2 MMEs, a 65% reduction), and this reduction was maintained through five months. The mean NRS score decreased by two points from baseline to one month (from 7.03 to 5.07; p < 0.0001), and this improvement was sustained at five months. The SF-36 Physical Functioning score increased from 15.3 at baseline to 21.4 at one month and was maintained at five months (p < 0.03 for both comparisons).

Conclusion: These results suggest that medical cannabis may be a useful adjunct therapy for reducing opioid use, relieving chronic pain, and improving health-related quality of life.”

https://pubmed.ncbi.nlm.nih.gov/42153072

“Opioids are associated with serious adverse events, including death, particularly at higher dosages or when used in combination with benzodiazepines.

In contrast, medical cannabis has not been associated with mortality from overdose. When used under appropriate medical supervision, medical cannabis may represent an effective adjunctive strategy for reducing opioid use among patients receiving long-term opioid therapy.

“Although cannabis has historically been characterized as a potential “gateway drug,” it may also serve as a harm-reduction tool for some patients seeking to reduce reliance on higher-risk opioid medications.”

https://www.cureus.com/articles/432327-medical-cannabis-as-an-opiate-alternative-a-prospective-observational-cohort-study#!

Effect of cannabidiol, cannabinol and tetrahydrocannabivarin in managing inflammatory pain

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“Current medications used to treat the inflammatory pain either have limited effectiveness or may be associated with serious side effects. Non-psychoactive phytocannabinoids may have a better safety profile and could be used as an alternative approach to treat this condition.

The aim of this study was to test the potential of three phytocannabinoids, cannabinol (CBN), tetrahydrocannabivarin (THCV) and cannabidiol (CBD), in treating inflammatory pain.

The inflammatory pain was triggered in male rats by a single intra-articular knee injection of the complete Freund’s adjuvant (CFA). One week later, rats were given four daily administrations of ibuprofen, CBN, THCV or CBD. Our data demonstrated that CFA injection triggered an inflammatory response expressed as damage of the synovial tissue, reduced locomotor activity, increased mechanical and, to a lesser extent, thermal pain sensitivity, and loss of body weight.

All phytocannabinoids reduced mechanical hyperalgesia and had no or a minor effect on locomotor activity.

Treatment with CBN also lowered thermal hypersensitivity. Treatment with CBN and THCV recovered the body weight of CFA-injected rats. However, administration of CBD reduced body weight and elevated blood monocyte and granulocyte levels above those of the CFA-injected control animal group.

We conclude that CBN and THCV may have potential in managing inflammatory pain.”

https://pubmed.ncbi.nlm.nih.gov/42151379

https://www.nature.com/articles/s41598-026-51275-7

Assessing the Efficacy of Cannabinoid Compositions for Treating 3 Classes of Chronic Pain: A Real-World Evidence Study

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“Purpose: Cannabis has been determined to be effective at treating chronic pain, although research on the effects of specific cannabinoids, especially for different mechanisms of chronic pain, is limited. This study examined therapeutic efficacy for combinations of intoxicating and nonintoxicating cannabinoids for symptoms of 3 different types of chronic pain conditions.

Methods: We recruited adult California residents diagnosed with fibromyalgia (n = 64), rheumatoid arthritis (n = 25), and osteoarthritis of the knee and/or hip (n = 75). Participants in each group were randomly assigned to receive a 12-week supply of oral capsules with 3 different cannabinoid compositions: product 1-12.5 mg cannabidiol (CBD) and 12.5 mg tetrahydrocannabinol (n = 45); product 2-10 mg tetrahydrocannabinolic acid, 10 mg cannabidiolic acid (CBDa), 5 mg cannabigerol, and 3 mg cannabichromene (n = 57); and product 3-10 mg CBD and 10 mg CBDa (n = 62). Participants completed validated self-report questionnaires assessing pain characteristics, mental health and cognitive functioning, and physical functioning at baseline and 12-week timepoints.

Findings: Of 276 individuals recruited, 168 (60.9%) completed all survey questionnaires. Four individuals who completed the questionnaires but discontinued study product use were removed from the dataset. Per-protocol analyses identified significant improvements across all symptoms except cognitive function abilities. Effects ranged from small to large; most did not differ in magnitude across product or type of chronic pain. Products differed in effectiveness for sleep disturbance, and participants taking product 2 reported reductions in neuropathic pain intensity.

Implications: These findings suggest that various cannabinoid combinations may have beneficial effects across 3 different types of chronic pain. Nonintoxicating cannabinoids such as CBD and CBDa may provide relief from pain and related symptoms and may be utilized when cannabis intoxication is undesirable or problematic.”

https://pubmed.ncbi.nlm.nih.gov/42140793

“Various cannabinoid combinations may have therapeutic benefits across 3 different types of chronic pain.”

https://www.clinicaltherapeutics.com/article/S0149-2918(26)00136-0/abstract

Cannabinoid receptors orchestrate distinct anti-tumour pathways in gastric cancer via and beyond specialized pro-resolving mediators

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“Endocannabinoids (ECS) and specialized pro-resolving mediators (SPMs) are both lipid-based compounds, but differ significantly in origin, mechanisms, and functions. Their mechanistic interaction in cancer remains undefined, particularly in gastric cancer (GC). Several interconnections have been described between these two “bioactive lipids” involved in inflammation resolution, homeostatic and anti-tumour functions.

Cannabinoid signalling can modulate SPM biosynthesis in immune cells, thus we investigated whether this crosstalk operates in GC cells, and whether SPMs mediate part of the anti-tumour activity of cannabinoid receptors.

Using synthetic and selective agonists for the cannabinoid G-protein-coupled receptors CB1 and CB2 (ACEA and JWH133, respectively), we found that receptor activation in GC cells (AGS and MKN45) sustains the synthesis of two SPMs, Resolvin D1 and Lipoxin B4, which in turn suppresses the angiogenic potential of GC cells. These CB1/CB2-driven activities required a SRC/MAPK signalling. At physiological concentrations, these SPMs further enhanced the binding affinity of ACEA and JWH133 for CB1 and CB2, indicating a functional crosstalk between the two systems.

Beyond angiogenesis, CB1/2 stimulation reduced cell proliferation and viability, induced apoptosis, impaired the migration and the epithelial-to-mesenchymal program in GC cells. Only CB2 activation reduced the stemness properties of GC cells. Interestingly, while the anti-angiogenic properties of CB1 and CB2 required SPM production, their other anti-tumour actions were independent of the pro-resolving pathway.

Our results extend the current knowledge of the endocannabinoid system by defining a new dual mechanism, SPM-dependent and SPM-independent, that restrains GC progression and identify the ECS-SPM axis as a potential target for therapeutic intervention.”

https://pubmed.ncbi.nlm.nih.gov/41775095

“CB1 and CB2 activation sustain potent anti-tumour effects in gastric cancer (GC).”

“In conclusion, this work demonstrates that cannabinoid receptor activation restrains gastric cancer cell proliferation, migration, stemness, and angiogenesis through both SPM-dependent and SPM-independent mechanisms. By linking ECS activation to pro-resolving lipid metabolism via SRC-ERK signalling, our data position CB1 and CB2 as regulators of tumour control rather than progression. These findings open the way for preclinical in vivo studies aimed at exploiting cannabinoid-SPM crosstalk as a novel therapeutic axis in gastric cancer.”

https://www.sciencedirect.com/science/article/pii/S0753332226002192?via%3Dihub

The greater the pleiotropic effects, the greater the benefits – cannabis as a “biopsychosocial” drug: a mixed-methods study on chronic non-cancer pain

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“Background: Against the background of widely inconsistent data from randomized controlled trials (RCT), the use of cannabis-based medicines (CBM) from the perspective of patients with chronic non-cancer pain (CNCP) was described.

Methods: Based on a purposive/convenient sampling, patients were recruited from the Pain Clinic of Hannover Medical School who had been using CBM prescribed by a doctor for at least 6 months. The patients discussed their experiences with CBM in semi-structured individual interviews. The interview transcripts were coded and analyzed using a modified grounded theory approach with the help of MAXQDA®. In addition, the Treatment Satisfaction Questionnaire with Medication (TSQM) was used.

Results: Theoretical saturation was reached after 32 interviews. Open and selective coding revealed the overarching phenomenon of “subjective pain experience under CBM therapy”, with one of the main themes being the “effect of CBM”. This revealed the categories “effect on pain” and “psychological” and “somatic effect”. The most important concepts were “pain intensity”, “pain management”, “stress management”, “musculoskeletal system”, and “sleep quality.” Constructing a theoretical framework 4 groups of responses to CBM treatment were identified. The focus is either on (I) pain reduction, (II) pain coping, (III) reduced stress or (IV) multidimensional aspects. When this classification was applied to topic of quality of life (QOL), the greatest effectiveness and highest overall satisfaction were found in group (IV). Mixed methods showed a continuous increase in the perceived effectiveness of CBM on pain-centered complaints from group (I) to (IV).

Conclusions: In line with the biopsychosocial understanding of chronic pain, it appears that those CNCP patients who benefit most from CBM are those who show the most far-reaching effects on both a physical and psychological level. The pleiotropic effects of CBM may be responsible for this. Based on these results, interdisciplinary prospective research appears sensible and necessary to further and systematically investigate this clinically relevant topic.”

https://pubmed.ncbi.nlm.nih.gov/42015327

https://link.springer.com/article/10.1186/s42238-026-00440-w

Electrophysiological modulation of pain‑related sodium channels by cannabinoids: a systematic review

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“Voltage-gated sodium channels regulate dorsal root ganglion excitability and are critical for nociceptive transmission. Cannabidiol (CBD) and related phytocannabinoids have been proposed to modulate these channels, offering potential non-opioid analgesic strategies. This systematic review evaluated their in vitro effects on pain-related sodium channels, focusing on electrophysiological and biophysical mechanisms.

Following PRISMA guidelines, Embase®, LILACS®, PubMed®/MEDLINE®, and Scopus® were searched using the SPIDER strategy. Eligible studies evaluated CBD or its derivatives on voltage-gated sodium channels Nav1.3, Nav1.6, Nav1.7, Nav1.8, and Nav1.9 through electrophysiological assays. Data extraction and analysis were conducted independently by two reviewers, with inter-rater agreement assessed by Cohen’s kappa. Seven studies met the inclusion criteria.

CBD consistently inhibited sodium currents with IC₅₀ values in the low micromolar range (2–3.3 µM), reduced action potential firing, induced hyperpolarizing shifts in steady-state inactivation, and delayed recovery from inactivation. Other phytocannabinoids, such as cannabigerol, cannabinol, cannabigerolic acid, and cannabidivarinic acid, also inhibited sodium channels, though with variable potency and distinct effects on channel gating.

Cannabinoids, particularly CBD, act as non-selective inhibitors of voltage-gated sodium channels implicated in pain signaling. Their ability to stabilize inactivated channel states and reduce neuronal excitability supports their therapeutic potential in neuropathic pain. These findings highlight the relevance of phytocannabinoids as promising candidates for the development of non-opioid analgesics.”

https://pubmed.ncbi.nlm.nih.gov/41987259

https://link.springer.com/article/10.1186/s42238-026-00436-6





Therapeutic relevance of an EU-GMP certified Cannabis sativa L. strain in a dual in vivo model of cognitive impairment and chronic neuropathic pain

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“Background: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and frequently co-occurs with chronic pain. Worldwide, over 55 million people are affected by AD, with nearly half experiencing persistent pain. Chronic pain has been linked to accelerated memory deterioration and an increased risk of dementia, but the interplay between these conditions remains poorly understood. Existing therapies for AD and chronic pain are limited in efficacy, highlighting the need for interventions targeting multiple pathological pathways. The endocannabinoid system, which is altered in both AD and chronic pain, represents a potential therapeutic target, though its role in AD patients with comorbid pain remains unexplored.

Methods: The study evaluated the effects of an EU-GMP certified Cannabis sativa L. strain (5 mg/kg, Cannabixir® Medium Flos) on neurobiological alterations in a rat model designed to explore mechanistic interactions between scopolamine-induced transient cognitive impairment and chronic neuropathic pain induced by unilateral sciatic nerve ligation. Treatment outcomes were assessed through nociceptive tests, clinical monitoring and tissue analyses to examine cognitive and pain-related effects.

Results: Cannabixir® Medium Flos induced robust, time-dependent analgesia in thermal nociceptive tests, with the combination of the Cannabis sativa L. strain, donepezil and tramadol producing significantly longer response latencies than tramadol alone. Mechanical sensitivity was minimally affected across treatments. Immunohistochemical analyses revealed that Cannabixir® Medium Flos, either alone or in combination with donepezil or tramadol, produced the most pronounced neuroprotective effects, reducing astrocytic (GFAP) and microglial (Iba1) activation, lowering Caspase-3 and IL-6 expression, and preserving both hippocampal neuronal integrity as well as peripheral nerve structure.

Conclusion: These findings indicate that Cannabixir® Medium Flos, particularly when combined with donepezil and tramadol, provides superior analgesic and neuroprotective effects compared to tramadol alone. Its multi-target action – alleviating thermal nociception, reducing neuroinflammation, limiting apoptosis and preserving neuronal and peripheral nerve integrity-supports its potential as an adjunct therapy in managing dementia with comorbid chronic neuropathic pain. Future studies should explore the molecular mechanisms underlying these effects and assess long-term safety and efficacy across diverse models of neurodegeneration and chronic pain.”

https://pubmed.ncbi.nlm.nih.gov/41800101

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2026.1761426/full

Potential effects of cannabidiol on formalin-induced inflammatory pain in morphine-dependent rats

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“Chronic morphine exposure leads to tolerance and dependence, complicating pain management and reducing the efficacy of opioid analgesics.

Cannabidiol (CBD), a non-psychoactive constituent of Cannabis sativa, has been recognized for its anti-inflammatory and analgesic potential.

This study examined the effects of CBD on acute and inflammatory phases of formalin-induced nociception in morphine-dependent and non-dependent rats.

Eighty-four male Wistar rats were divided into the control (non-dependent) and dependent groups. Morphine dependence was induced through an oral escalating-dose regimen in drinking water containing 3% sucrose (to mask bitterness) for 14 days, while controls received only sucrose. CBD (25-200μg/5 μL, ICV) was administered prior to the formalin test. Formalin injection produced a clear biphasic nociceptive response (P < 0.001 in both phases), confirming the model’s validity.

Morphine dependence alone did not significantly affect baseline pain responses (P > 0.05). However, CBD produced a significant, dose-dependent reduction in pain behaviors during both the early (0-5 min) and the late (20-50 min) phases (P<0.001 vs. vehicle). The 100 μg/5 μL and 200 μg/5 μL doses showed the most robust and consistent antinociceptive effect.

CBD produced robust antinociceptive effects in both morphine-treated and non-treated rats, with no statistically significant difference between groups. Open-field results indicated no significant differences in locomotor activity, confirming that the observed analgesia was not related to motor impairment.

These findings demonstrate that CBD effectively attenuates both acute and inflammatory pain. Moreover, it maintains its effectiveness in animals treated with morphine. This highlights its potential as a non-opioid supplementary therapy for managing pain in individuals with opioid dependence.”

https://pubmed.ncbi.nlm.nih.gov/41747636

https://www.sciencedirect.com/science/article/abs/pii/S0022395626001263?via%3Dihub

Cannabidiol reduces oxycodone self-administration while preserving its analgesic efficacy in a rat model of neuropathic pain

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“Prescription opioid misuse is a significant public health concern among individuals with chronic pain. Treating severe pain often requires high doses of opioids, increasing the risk of developing an opioid use disorder.

Cannabidiol (CBD) is a non-intoxicating component of cannabis that has shown therapeutic potential without abuse liability.

This study investigated the effects of CBD on oxycodone self-administration and hyperalgesia in an animal model of chronic neuropathic pain.

Adult male rats were trained to self-administer intravenous oxycodone (0.06 mg/kg/infusion). Subsequently, they underwent chronic constriction injury (CCI) of the sciatic nerve or received sham surgery. Paw withdrawal latency was measured using the Hargreaves test as an indicator of thermal pain sensitivity. CBD (0, 1, 3, and 10 mg/kg, IP) was administered before the self-administration sessions, and pain testing was conducted afterward. The rats acquired oxycodone self-administration, as indicated by more active than inactive lever presses. CCI surgery decreased the paw withdrawal latency, confirming the induction of neuropathic pain. CCI alone did not affect oxycodone self-administration, suggesting that neuropathic pain does not substantially influence opioid intake at the dose tested.

Treatment with CBD reduced oxycodone self-administration in both the sham and CCI rats. Oxycodone self-administration in the CCI rats reversed the CCI-induced decrease in paw withdrawal latency. However, CBD did not affect the antinociceptive effect of oxycodone in CCI rats.

Taken together, these findings demonstrate that CBD reduces oxycodone self-administration without affecting the antinociceptive effects of oxycodone in neuropathic pain.

This study supports the potential of CBD to reduce opioid use and misuse, regardless of pain status.”

https://pubmed.ncbi.nlm.nih.gov/41521216

https://www.nature.com/articles/s41598-025-31828-y