Category Archives: Chronic Inflammatory and Neuropathic Pain

Protective role of neuronal and lymphoid cannabinoid CB 2 receptors in neuropathic pain

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 eLife logo“Cannabinoid CB2 receptor (CB2) agonists are potential analgesics void of psychotropic effects.

Peripheral immune cells, neurons and glia express CB2, however the involvement of CB2 from these cells in neuropathic pain remains unresolved. We explored spontaneous neuropathic pain through on-demand self-administration of the selective CB2 agonist JWH133 in wild-type and knockout mice lacking CB2 in neurons, monocytes or constitutively. Operant self-administration reflected drug-taking to alleviate spontaneous pain, nociceptive and affective manifestations. While constitutive deletion of CB2 disrupted JWH133-taking behavior, this behavior was not modified in monocyte-specific CB2 knockouts and was increased in mice defective in neuronal CB2 knockouts suggestive of increased spontaneous pain. Interestingly, CB2-positive lymphocytes infiltrated the injured nerve and possible CB2transfer from immune cells to neurons was found. Lymphocyte CB2depletion also exacerbated JWH133 self-administration and inhibited antinociception.

This work identifies a simultaneous activity of neuronal and lymphoid CB2that protects against spontaneous and evoked neuropathic pain.”

https://pubmed.ncbi.nlm.nih.gov/32687056/

https://elifesciences.org/articles/55582

The pharmacokinetics, efficacy, and safety of a novel selective‐dose cannabis inhaler in patients with chronic pain: A randomized, double‐blinded, placebo‐controlled trial

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European Journal of Pain“Precise cannabis treatment dosing remains a major challenge, leading to physicians’ reluctance to prescribe medical cannabis.

Objective

To test the pharmacokinetics, analgesic effect, cognitive performance and safety effects of an innovative medical device that enables the delivery of inhaled therapeutic doses of Δ9‐Tetrahydrocannabinol (THC) in patients with chronic pain.

Methods

In a randomized, three‐arms, double‐blinded, placebo‐controlled, cross‐over trial, 27 patients received a single inhalation of Δ9‐THC: 0.5mg, 1mg, or a placebo.

Δ9‐THC plasma levels were measured at baseline and up to 150‐min post‐inhalation. Pain intensity and safety parameters were recorded on a 10‐cm visual analogue scale (VAS) at pre‐defined time points. The cognitive performance was evaluated using the selective sub‐tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB).

Results

Following inhalation of 0.5 mg or 1mg, Δ9‐THC plasma C max ± SD were 14.3 ± 7.7 and 33.8 ± 25.7 ng/ml. T max ± SD were 3.7 ± 1.4 and 4.4 ± 2.1 min, and AUC0 → infinity±SD were 300 ± 144 and 769 ± 331 ng*min/ml, respectively. Both doses, but not the placebo, demonstrated a significant reduction in pain intensity compared with baseline and remained stable for 150‐min. The 1‐mg dose showed a significant pain decrease compared to the placebo. Adverse events were mostly mild and resolved spontaneously. There was no evidence of consistent impairments in cognitive performance.

Conclusion

This feasibility trial demonstrated that a metered‐dose cannabis inhaler delivered precise and low THC doses, produced a dose‐dependent and safe analgesic effect in patients with neuropathic pain/ complex‐regional pain syndrome (CRPS). Thus, it enables individualization of medical cannabis regimens that can be evaluated pharmacokinetically and pharmacodynamically by accepted pharmaceutical models.

Significance

Evidence suggests that cannabis‐based medicines are an effective treatment for chronic pain in adults. The pharmacokinetics of THC varies as a function of its route of administration. Pulmonary assimilation of inhaled THC causes rapid onset of analgesia. However, currently used routes of cannabinoids delivery provide unknown doses, making it impossible to implement a pharmaceutical standard treatment plan. A novel selective‐dose cannabis inhaler delivers significantly low and precise doses of THC, thus allowing the administration of inhaled cannabis‐based medicines according to high pharmaceutical standards. These low doses of THC can produce safe and effective analgesia in patients with chronic pain.

To the best of our knowledge, it is the first time that the delivery of selective, significantly low, and precise therapeutic single doses of inhaled THC demonstrates an analgesic effect. It allows patients to reach the optimum balance between symptom relief and controlled side effects, enabling patients to regain their quality of life. In addition, this metered‐dose cannabis inhaler enables the individualization of medical cannabis regimens that can be evaluated pharmacokinetically and pharmacodynamically using accepted pharmaceutical models.”

https://onlinelibrary.wiley.com/doi/10.1002/ejp.1605

“Study Finds Microdosing THC Reduces Pain Levels”  https://www.painnewsnetwork.org/stories/2020/7/1/study-finds-microdosing-thc-reduces-pain-levels

Medical Cannabis for the Management of Pain and Quality of Life in Chronic Pain Patients: A Prospective Observational Study

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Pain Medicine (Journal) by Oxford University Press

“Objective: To evaluate the short-term and long-term effects of plant-based medical cannabis in a chronic pain population over the course of one year.

Results: Medical cannabis treatment was associated with improvements in pain severity and interference (P < 0.001) observed at one month and maintained over the 12-month observation period. Significant improvements were also observed in the SF-12 physical and mental health domains (P < 0.002) starting at three months. Significant decreases in headaches, fatigue, anxiety, and nausea were observed after initiation of treatment (P ≤ 0.002). In patients who reported opioid medication use at baseline, there were significant reductions in oral morphine equivalent doses (P < 0.0001), while correlates of pain were significantly improved by the end of the study observation period.

Conclusions: Taken together, the findings of this study add to the cumulative evidence in support of plant-based medical cannabis as a safe and effective treatment option and potential opioid medication substitute or augmentation therapy for the management of symptoms and quality of life in chronic pain patients.”

https://pubmed.ncbi.nlm.nih.gov/32556203/

https://academic.oup.com/painmedicine/article-abstract/doi/10.1093/pm/pnaa163/5859722?redirectedFrom=fulltext

A Balanced Approach for Cannabidiol Use in Chronic Pain

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Frontiers in Pharmacology (@FrontPharmacol) | Twitter “Cannabidiol (CBD), the major non-psychoactive constituent of Cannabis sativa L., has gained traction as a potential treatment for intractable chronic pain in many conditions. Clinical evidence suggests that CBD provides therapeutic benefit in certain forms of epilepsy and imparts analgesia in certain conditions, and improves quality of life.

CBD continues to be Schedule I or V on the list of controlled substances of the Drug Enforcement Agency of the United States. However, preparations labeled CBD are available publicly in stores and on the streets. However, use of CBD does not always resolve pain. CBD purchased freely entails the risk of adulteration by potentially hazardous chemicals. As well, CBD use by pregnant women is rising and poses a major health-hazard for future generations.

In this mini-review, we present balanced and unbiased pre-clinical and clinical findings for the beneficial effects of CBD treatment on chronic pain and its deleterious effects on prenatal development.”

https://pubmed.ncbi.nlm.nih.gov/32425793/

https://www.frontiersin.org/articles/10.3389/fphar.2020.00561/full

www.frontiersin.org

The Therapeutic Effectiveness of Full Spectrum Hemp Oil Using a Chronic Neuropathic Pain Model

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life-logo“Few models exist that can control for placebo and expectancy effects commonly observed in clinical trials measuring ‘Cannabis’ pharmacodynamics. We used the Foramen Rotundum Inflammatory Constriction Trigeminal Infraorbital Nerve injury (FRICT-ION) model to measure the effect of “full-spectrum” whole plant extracted hemp oil on chronic neuropathic pain sensitivity in mice.

Results: Mechanical allodynia was alleviated within 1 h (d = 2.50, p < 0.001) with a peak reversal effect at 4 h (d = 7.21, p < 0.001) and remained significant throughout the 6 h observation window. There was no threshold change on contralateral whisker pad after hemp oil administration, demonstrating the localization of anesthetic response to affected areas.

Conclusion: Future research should focus on how whole plant extracted hemp oil affects multi-sensory and cognitive-attentional systems that process pain.

The present study shows for the first time that common, commercially available, and easily reproducible full-spectrum hemp oil induces significant anti-allodynic effects with a bell-shaped pain sensitivity effect peeking between 2 and 4 h and lasting over 6 h. The study provides evidence that phytochemical extracts of the Cannabis plant, even with relatively low levels of THC, can significantly improve mechanical pressure pain in animals with established chronic neuropathic hypersensitivity.”

https://www.mdpi.com/2075-1729/10/5/69/htm

“Legal Cannabis hemp oil effectively treats chronic neuropathic pain: study”   https://medicalxpress.com/news/2020-05-legal-cannabis-hemp-oil-effectively.html

The molecular mechanisms that underpin the biological benefit of full spectrum cannabis extract in the treatment of neuropathic pain and inflammation.

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Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease“Cannabis has been shown to be beneficial in the treatment of pain and inflammatory diseases.

The biological effect of cannabis is mainly attributed to two major cannabinoids, tetrahydrocannabinol and cannabidiol. In the majority of studies to-date, a purified tetrahydrocannabinol and cannabidiol alone or in combination have been extensively examined in many studies for the treatment of numerous disorders including pain and inflammation. However, few studies have investigated the biological benefits of full-spectrum cannabis plant extract.

Given that cannabis is known to generate a large number of cannabinoids along with numerous other biologically relevant products including terpenes, studies involving purified tetrahydrocannabinol and/or cannabidiol may not precisely consider the potential biological benefits of the full-spectrum cannabis extracts. This may be especially true in the role of cannabis as a treatment of pain and inflammation. Herein, we review the pre-clinical physiological and molecular mechanisms in biological systems that are affected by cannabis.”

https://www.ncbi.nlm.nih.gov/pubmed/32201189

“Full-spectrum cannabis extract demonstrates several convincing beneficial anti-inflammatory and analgesic effects in preclinical studies. Full-spectrum cannabis extract may represent a promising therapeutic agent that seems to benefit a variety of conditions associated with pain and inflammation.”

https://www.sciencedirect.com/science/article/abs/pii/S0925443920301162?via%3Dihub

Analgesic Effects of Cannabinoids for Chronic Non-cancer Pain: a Systematic Review and Meta-Analysis with Meta-Regression.

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SpringerLink “There is growing interest in using cannabinoids for chronic pain.

We performed a systematic review and meta-analysis of randomized controlled trials to evaluate the analgesic efficacy and adverse effects of cannabinoids for chronic non-cancer pain.

PubMed, EMBASE, Web of Science, Cochrane CENTRAL and clinicaltrials.gov were searched up to December 2018. Information on the type, dosage, route of administration, pain conditions, pain scores, and adverse events were extracted for qualitative analysis. Meta-analysis of analgesic efficacy was performed. Meta-regression was performed to compare the analgesic efficacy for different pain conditions (neuropathic versus non-neuropathic pain). Risk of bias was assessed by The Cochrane Risk of Bias tool, and the strength of the evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Forty-three randomized controlled trials were included. Meta-analysis was performed for 33 studies that compared cannabinoids to placebo, and showed a mean pain score (scale 0-10) reduction of -0.70 (p < 0.001, random effect). Meta-regression showed that analgesic efficacy was similar for neuropathic and non-neuropathic pain (Difference = -0.14, p = 0.262).

Inhaled, oral, and oromucosal administration all provided statistically significant, but small reduction in mean pain score (-0.97, -0.85, -0.45, all p < 0.001). Incidence of serious adverse events was rare, and non-serious adverse events were usually mild to moderate. Heterogeneity was moderate.

The GRADE level of evidence was low to moderate. Pain intensity of chronic non-cancer patients was reduced by cannabinoids consumption, but effect sizes were small. Efficacy for neuropathic and non-neuropathic pain was similar.”

https://www.ncbi.nlm.nih.gov/pubmed/32172501

https://link.springer.com/article/10.1007%2Fs11481-020-09905-y

The role of the cannabinoid system in opioid analgesia and tolerance.

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“Opioid receptor agonist drugs, such as morphine, are very effective for treating chronic and severe pain; but, tolerance can develop with long-term use. Although there is a lot of information about the pathophysiological mechanisms of opioid tolerance, it is still not fully clarified. Suggested mechanisms for opioid tolerance include opioid receptor desensitisation, reduction of sensitivity G-proteins, activation of mitogen-activated protein kinase (MAPK), altered intracellular signaling pathway including nitric oxide, and activation of mammalian target of rapamycin (mTOR).

One way to reduce opioid tolerance and increase the analgesic potential is to use low doses. Combination of cannabinoids with opioids has been shown to manifest reduce the opioid dose. Experimental studies revealed an interaction of the endocannabinoid system and opioid antinociception.

Cannabinoid and opioid receptor systems use common pathways in the formation of analgesic effect and demonstrate their activity via G protein coupled receptors (GPCR). Cannabinoid drugs modulate opioid analgesic activity at a number of distinct levels within the cell, ranging from direct receptor associations, to post-receptor interactions through shared signal transduction pathways.

This review summarizes the data indicating that with combining cannabinoids and opioids drugs may be able to produce long-term analgesic effects, while preventing the opioid analgesic tolerance.”

https://www.ncbi.nlm.nih.gov/pubmed/32167427

http://www.eurekaselect.com/180186/article

Antinociceptive and Immune Effects of Delta-9-tetrahydrocannabinol or Cannabidiol in Male Versus Female Rats with Persistent Inflammatory Pain.

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Journal of Pharmacology and Experimental Therapeutics: 373 (1)

“Chronic pain is the most common reason reported for using medical cannabis.

The goal of this research was to determine if the two primary phytocannabinoids, THC and CBD, are effective treatments for persistent inflammatory pain.

These results suggest that THC may be more beneficial than CBD for reducing inflammatory pain, in that THC maintains its efficacy with short-term treatment in both sexes, and does not induce immune activation.

SIGNIFICANCE STATEMENT: CBDs and THCs pain-relieving effects are examined in male and female rats with persistent inflammatory pain to determine if individual phytocannabinoids could be a viable treatment for men and women with chronic inflammatory pain. Additionally, sex differences in the immune response to an adjuvant and to THC and CBD are characterized to provided preliminary insight into immune-related effects of cannabinoid-based therapy for pain.”

https://www.ncbi.nlm.nih.gov/pubmed/32179573

http://jpet.aspetjournals.org/content/early/2020/03/16/jpet.119.263319

A Review of Scientific Evidence for THC:CBD Oromucosal Spray (Nabiximols) in the Management of Chronic Pain.

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“The 20% prevalence of chronic pain in the general population is a major health concern given the often profound associated impairment of daily activities, employment status, and health-related quality of life in sufferers. Resource utilization associated with chronic pain represents an enormous burden for healthcare systems. Although analgesia based on the World Health Organization’s pain ladder continues to be the mainstay of chronic pain management, aside from chronic cancer pain or end-of-life care, prolonged use of non-steroidal anti-inflammatory drugs or opioids to manage chronic pain is rarely sustainable.

As the endocannabinoid system is known to control pain at peripheral, spinal, and supraspinal levels, interest in medical use of cannabis is growing.

A proprietary blend of cannabis plant extracts containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) as the principal cannabinoids is formulated as an oromucosal spray (USAN name: nabiximols) and standardized to ensure quality, consistency and stability. This review examines evidence for THC:CBD oromucosal spray (nabiximols) in the management of chronic pain conditions.

Cumulative evidence from clinical trials and an exploratory analysis of the German Pain e-Registry suggests that add-on THC:CBD oromucosal spray (nabiximols) may have a role in managing chronic neuropathic pain, although further precise clinical trials are required to draw definitive conclusions.”

https://www.ncbi.nlm.nih.gov/pubmed/32104061

https://www.dovepress.com/a-review-of-scientific-evidence-for-thccbd-oromucosal-spray-nabiximols-peer-reviewed-article-JPR

“Smoked Cannabis Proven Effective In Treating Neuropathic Pain.” https://www.sciencedaily.com/releases/2007/10/071024141745.htm

“Marijuana Relieves Chronic Pain, Research Shows” https://www.webmd.com/pain-management/news/20100830/marijuana-relieves-chronic-pain-research-show#1