Category Archives: Chronic Inflammatory and Neuropathic Pain

The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

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ijms-logo“The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems.

In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development.

The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development.

The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases.

This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as “C. sativa L.” or “medical cannabis”), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.”

https://pubmed.ncbi.nlm.nih.gov/34502379/

https://www.mdpi.com/1422-0067/22/17/9472

“Cannabis sativa L. as a Natural Drug Meeting the Criteria of a Multitarget Approach to Treatment”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830475/

Risk and benefit of cannabis prescription for chronic non-cancer pain

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Taylor and Francis Online“Objectives: We investigated whether cannabis usage was associated with reduced opioid usage, and the rates of opioid and cannabis use disorders among chronic pain patients who had been prescribed medical cannabis.

Results: Of the 100 participants aged 18-70 years (compliance 67% (aged >40) and 33% (aged ≤ 40y)), 76 ever used opioids. Of them, 93% decreased or stopped opioids following cannabis initiation. Ten patients (10%), 17.4% of the ≤40 y age group, met the criteria for cannabis use disorder. Compared to those who did not meet the criteria, their lifetime depression was higher (80% vs. 43.2%, respectively, P=.042), and they were less educated (12.2 ± 0.6y vs. 13.5 ± 2.1y, p = 0.05).

Conclusions: Cannabis usage was associated with reduced opioid usage. The prevalence of cannabis use disorder was high among the younger participants who also had a lower study compliance rate, suggesting the higher actual prevalence of cannabis use disorder. While medical cannabis may help reduce opioid use in chronic non-cancer pain patients, younger age, depression, and other risk factors should be carefully evaluated before cannabis is prescribed.”

https://pubmed.ncbi.nlm.nih.gov/34338621/

“Cannabis usage was associated with reduced opioid usage.”

https://www.tandfonline.com/doi/abs/10.1080/10550887.2021.1956673?journalCode=wjad20

Prolonged Medical Cannabis Treatment is Associated With Quality of Life Improvement and Reduction of Analgesic Medication Consumption in Chronic Pain Patients

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Frontiers in Pharmacology (@FrontPharmacol) | Twitter“Introduction: Chronic non-cancer pain (CNCP) is one of the most prevalent indications for medical cannabis (MC) treatment globally. In this study, we investigated CNCP parameters in patients during prolonged MC treatment, and assessed the interrelation between CNCP parameters and the chemical composition of MC chemovar used. 

Methods: A cross-sectional questionnaire-based study was performed in one-month intervals for the duration of six months. Subjects were adult patients licensed for MC treatment who also reported a diagnosis of CNCP by a physician. Data included self-reported questionnaires. MC treatment features included administration route, cultivator, cultivar name and monthly dose. Comparison statistics were used to evaluate differences between the abovementioned parameters and the monthly MC chemovar doses at each time point. 

Results: 429, 150, 98, 71, 77 and 82 patients reported fully on their MC treatment regimens at six one-month intervals, respectively. Although pain intensities did not change during the study period, analgesic medication consumption rates decreased from 46 to 28% (p < 0.005) and good Quality of Life (QoL) rates increased from 49 to 62% (p < 0.05). These changes overlapped with increase in rates of (-)-Δ9–trans-tetrahydrocannabinol (THC) and α-pinene high dose consumption. 

Conclusion: Even though we observed that pain intensities did not improve during the study, QoL did improve and the rate of analgesic medication consumption decreased alongside with increasing rates of high dose THC and α-pinene consumption. Understanding MC treatment composition may shed light on its long-term effects.”

https://pubmed.ncbi.nlm.nih.gov/34093173/

“In this study, although pain intensities did not change under long-term MC treatment, analgesic medication consumption rates decreased and ‘better’ QoL rates increased. These changes coincided with the increased rates of patients’ consumption of high dose THC and α pinene. These results may shed light on the long-term beneficial effects of MC on CNCP.”

https://www.frontiersin.org/articles/10.3389/fphar.2021.613805/full

Cannabis Significantly Reduces the Use of Prescription Opioids and Improves Quality of Life in Authorized Patients: Results of a Large Prospective Study

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Pain Medicine“Objectives: This article presents findings from a large prospective examination of Canadian medical cannabis patients, with a focus on the impacts of cannabis on prescription opioid use and quality of life over a 6-month period.

Results: Participants were 57.6% female, with a median age of 52 years. Baseline opioid use was reported by 28% of participants, dropping to 11% at 6 months. Daily opioid use went from 152 mg morphine milligram equivalent (MME) at baseline to 32.2 mg MME at 6 months, a 78% reduction in mean opioid dosage. Similar reductions were also seen in the other four primary prescription drug classes identified by participants, and statistically significant improvements were reported in all four domains of the WHOQOL-BREF.

Conclusions: This study provides an individual-level perspective of cannabis substitution for opioids and other prescription drugs, as well as associated improvement in quality of life over 6 months. The high rate of cannabis use for chronic pain and the subsequent reductions in opioid use suggest that cannabis may play a harm reduction role in the opioid overdose crisis, potentially improving the quality of life of patients and overall public health.”

https://pubmed.ncbi.nlm.nih.gov/33367882/

https://academic.oup.com/painmedicine/advance-article-abstract/doi/10.1093/pm/pnaa396/6053211?redirectedFrom=fulltext

Antinociception mechanisms of action of cannabinoid-based medicine: an overview for anesthesiologists and pain physicians

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 Pain Rounds“Cannabinoid-based medications possess unique multimodal analgesic mechanisms of action, modulating diverse pain targets.

Cannabinoids are classified based on their origin into three categories: endocannabinoids (present endogenously in human tissues), phytocannabinoids (plant derived) and synthetic cannabinoids (pharmaceutical). Cannabinoids exert an analgesic effect, peculiarly in hyperalgesia, neuropathic pain and inflammatory states.

Endocannabinoids are released on demand from postsynaptic terminals and travels retrograde to stimulate cannabinoids receptors on presynaptic terminals, inhibiting the release of excitatory neurotransmitters. Cannabinoids (endogenous and phytocannabinoids) produce analgesia by interacting with cannabinoids receptors type 1 and 2 (CB1 and CB2), as well as putative non-CB1/CB2 receptors; G protein-coupled receptor 55, and transient receptor potential vanilloid type-1. Moreover, they modulate multiple peripheral, spinal and supraspinal nociception pathways.

Cannabinoids-opioids cross-modulation and synergy contribute significantly to tolerance and antinociceptive effects of cannabinoids. This narrative review evaluates cannabinoids’ diverse mechanisms of action as it pertains to nociception modulation relevant to the practice of anesthesiologists and pain medicine physicians.”

https://pubmed.ncbi.nlm.nih.gov/33239391/

https://rapm.bmj.com/content/early/2020/11/24/rapm-2020-102114

Medical Cannabis Treatment for Chronic Pain: Outcomes and Prediction of Response

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“Although studied in a few randomized controlled trials (RCTs), the efficacy of medical cannabis (MC) for chronic pain remains controversial. Using an alternative approach, this multicenter, questionnaire-based prospective cohort was aimed to assess the long-term effects of MC on chronic pain of various etiologies and to identify predictors for MC treatment success.

Results: 1045 patients completed the baseline questionnaires and initiated MC treatment, and 551 completed the 12 month follow-up. At one year, average pain intensity declined from baseline by 20% [-1.97 points (95%CI= -2.13 to -1.81; p<0.001)]. All other parameters improved by 10-30% (p<0.001). A significant decrease of 42% [reduction of 27mg; (95%CI= -34.89 to -18.56, p<0.001)] from baseline in morphine equivalent daily dosage of opioids was also observed. Reported adverse effects were common but mostly non-serious. Presence of normal to long sleep duration, lower body mass index (BMI) and lower depression score predicted relatively higher treatment success, whereas presence of neuropathic pain predicted the opposite.

Conclusions: This prospective study provides further evidence for the effects of MC on chronic pain and related symptoms, demonstrating an overall mild to modest long-term improvement of the tested measures and identifying possible predictors for treatment success.

Significance: This “real world” paper shows that MC mildly to modestly attenuates chronic pain and related symptoms. MC treatment can also cause frequent, but mostly non-serious adverse effects, although central nervous system (CNS)-related AEs that can impair the ability to drive vehicles are not uncommon. This study is novel in identifying possible predictors for treatment success, including normal to long sleep duration, lower BMI and lower depression scores. In contrast to current beliefs the diagnosis of neuropathic pain predicts a less favorable outcome. These findings provide physicians with new data to support decision making on recommendations for MC treatment.”

https://pubmed.ncbi.nlm.nih.gov/33065768/

https://onlinelibrary.wiley.com/doi/10.1002/ejp.1675

Cannabinoid Receptors and Their Relationship With Chronic Pain: A Narrative Review

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CB1-versus-CB2-receptors “The burden of chronic pain has affected many individuals leading to distress and discomfort, alongside numerous side effects with conventional therapeutic approaches.

Cannabinoid receptors are naturally found in the human body and have long been an interest in antinociception. These include CB1 and CB2 receptors, which are promising candidates for the treatment of chronic inflammatory pain.

The mechanism of action of the receptors and how they approach pain control in inflammatory conditions show that it can be an adjunctive approach towards controlling these symptoms. Numerous studies have shown how the targeted approach towards these receptors has activated them promoting a release in cytokines, all leading to anti-inflammatory effects and immune system regulation.

Cannabinoid activation of glycine and gamma-aminobutyric acid (GABA) models also showed efficacy in pain management. Chronic conditions such as osteoarthritis were shown to also benefit from this considerable treatment. However, it is unclear how the cannabinoid system works in relation with the pain pathway. Therefore, in this review we aim to analyse the role of the cannabinoid system in chronic inflammatory pain.”

https://pubmed.ncbi.nlm.nih.gov/33072446/

https://www.cureus.com/articles/39887-cannabinoid-receptors-and-their-relationship-with-chronic-pain-a-narrative-review

The CB2 Agonist β-Caryophyllene in Male and Female Rats Exposed to a Model of Persistent Inflammatory Pain

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frontiers – Page 2 – Retraction Watch “Cannabinoids help in pain treatment through their action on CB1 and CB2 receptors.

β-caryophyllene (BCP), an ancient remedy to treat pain, is a sesquiterpene found in large amounts in the essential oils of various spice and food plants such as oregano, cinnamon, and black pepper. It binds to the CB2 receptor, acting as a full agonist.

Sex differences in the BCP-induced analgesic effect were studied by exposing male and female rats to a persistent/repeated painful stimulation.

In conclusion, long-term intake of BCP appears to be able to decrease pain behaviors in a model of repeated inflammatory pain in both sexes, but to a greater degree in males.”

https://pubmed.ncbi.nlm.nih.gov/33013287/

https://www.frontiersin.org/articles/10.3389/fnins.2020.00850/full

“β-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis.”   http://www.ncbi.nlm.nih.gov/pubmed/23138934

“Beta-caryophyllene is a dietary cannabinoid.”   https://www.ncbi.nlm.nih.gov/pubmed/18574142

No Evidence of Altered Reactivity to Experimentally Induced Pain Among Regular Cannabis Users

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Clinical Journal of Pain,Philadelphia - Gainbuzz“Recent years have seen an increase in the adoption of cannabinoid medicines, which have demonstrated effectiveness for the treatment of chronic pain.

However, the extent to which frequent cannabis use (CU) influences sensitivity to acute pain has not been systematically examined. Such a determination is clinically relevant in light of hypersensitivity to pain associated with prolonged use of other analgesics such as opioids, and reports of increased pain sensitivity to experimentally induced pain during acute cannabis intoxication.

This study explored differences in measures of pain intensity and tolerance. The authors hypothesized that individuals who report frequent CU would demonstrate greater experimental pain sensitivity.

Results: Frequent CU was not associated with hyperalgesia as cannabis users and nonusers did not exhibit differences on measures of pain tolerance (t (78)=-0.05; P=0.96), sensitivity (t (78)=-0.83; P=0.41), or intensity (t (78)=0.36; P=0.72).

Discussion: Frequent cannabis users did not demonstrate hyperalgesia. This finding should help to inform evaluations of the relative harms and benefits of cannabis analgesic therapies.”

https://pubmed.ncbi.nlm.nih.gov/32433075/

https://journals.lww.com/clinicalpain/Abstract/2020/08000/No_Evidence_of_Altered_Reactivity_to.4.aspx

“Pain tolerance among cannabis users. Unlike opioids, long-term cannabis use does not increase sensitivity to pain. “This study should come as good news to patients who are already using cannabis to treat pain,” says co-author Zach Walsh, who leads the UBC Therapeutic Recreational and Problematic Substance Use Lab which hosted the study. “Increases in pain sensitivity with opioids can really complicate an already tough situation; given increasing uptake of cannabis-based pain medications it’s a relief that we didn’t identify a similar pattern with cannabinoids.”

https://www.sciencedaily.com/releases/2020/09/200910120105.htm

Insights on cannabidiol’s antiallodynic and anxiolytic mechanisms of action in a model of neuropathic pain

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PAIN Impact Factor Increase to 6.029 - IASP“Recent studies have shown that cannabidiol (CBD) could have a great therapeutic potential for treating disorders such as chronic pain and anxiety. In the target article, the authors propose that CBD modulates serotonergic transmission and reverses allodynia and anxiety-like behaviour in a rat model of neuropathic pain. Furthermore, this study shows an antinociceptive effect mediated by TRPV1 and partially by 5-HT1A receptors, as well as an anxiolytic effect mediated by 5-HT1A receptors.”

https://pubmed.ncbi.nlm.nih.gov/32766463/

https://journals.lww.com/painrpts/Fulltext/2019/10000/Insights_on_cannabidiol_s_antiallodynic_and.10.aspx

“Cannabidiol modulates serotonergic transmission and reverses both allodynia and anxiety-like behavior in a model of neuropathic pain”  https://pubmed.ncbi.nlm.nih.gov/30157131/