Category Archives: Chronic Inflammatory and Neuropathic Pain

The Analgesic Potential of Cannabinoids

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“Cannabinoids are derivatives of Cannabis sativa, the hemp plant, which evolved in the temperate regions of Central Asia. Cannabis was used as a medicine in ancient China (2700 BC) and India (1000 BC). Historically and anecdotally cannabinoids have been used as analgesic agents.

In recent years, there has been an escalating interest in developing cannabis-derived medications to treat severe pain. This review provides an overview of the history of cannabis use in medicine, cannabinoid signaling pathways, and current data from preclinical as well as clinical studies on using cannabinoids as potential analgesic agents. Clinical and experimental studies show that cannabis-derived compounds act as anti-emetic, appetite modulating and analgesic agents.

Since opioids are the only therapy for severe pain, analgesic ability of cannabinoids may provide a much-needed alternative to opioids. Moreover, cannabinoids act synergistically with opioids and act as opioid sparing agents, allowing lower doses and fewer side effects from chronic opioid therapy. Thus, rational use of cannabis based medications deserves serious consideration to alleviate the suffering of patients due to severe pain.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3728280/

[Therapeutic potential of Cannabis sativa].

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SciELO - Scientific Electronic Library Online

“Cannabis sativa (marihuana) is considered an illicit drug due to its psychoactive properties. Recently, the Chilean government opened to the use cannabis in the symptomatic treatment of some patients. The biological effects of cannabis render it useful for the complementary treatment of specific clinical situations such as chronic pain. We retrieved scientific information about the analgesic properties of cannabis, using it as a safe drug. The drug may block or inhibit the transmission of nervous impulses at different levels, an effect associated with pain control. Within this context and using adequate doses, forms and administration pathways, it can be used for chronic pain management, considering its effectiveness and low cost. It could also be considered as an alternative in patients receiving prolonged analgesic therapies with multiple adverse effects.”

 https://www.ncbi.nlm.nih.gov/pubmed/28548193
http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872017000300010&lng=en&nrm=iso&tlng=en

Single and combined effects of delta9 -tetrahydrocannabinol and cannabidiol in a mouse model of chemotherapy-induced neuropathic pain.

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British Journal of Pharmacology

“It has been suggested that the non-psychoactive phytocannabinoid cannabidiol (CBD) can impact the pharmacological effects of delta-9-tetrahydrocannabinol (THC). We tested the hypothesis that CBD and THC would significantly mitigate mechanical sensitivity in a mouse model of paclitaxel-induced neuropathic pain, and that CBD+THC combinations would produce synergistic effects. We also tested the hypothesis that CBD would attenuate oxaliplatin- and vincristine- induced mechanical sensitivity.

KEY RESULTS:

Both CBD and THC alone attenuated mechanical allodynia in mice treated with paclitaxel. Very low ineffective doses of CBD and THC were synergistic when given in combination. CBD also attenuated oxaliplatin- but not vincristine-induced mechanical sensitivity, while THC significantly attenuated vincristine- but not oxaliplatin-induced mechanical sensitivity. The low dose combination significantly attenuated oxaliplatin- but not vincristine-induced mechanical sensitivity.

CONCLUSIONS AND IMPLICATIONS:

CBD may be potent and effective at preventing the development of CIPN, and its clinical utility may be enhanced by co-administration of low doses of THC. These treatment strategies would increase the therapeutic window of Cannabis-based pharmacotherapies.”

https://www.ncbi.nlm.nih.gov/pubmed/28548225

http://onlinelibrary.wiley.com/doi/10.1111/bph.13887/abstract

Selective Cannabinoids for Chronic Neuropathic Pain: A Systematic Review and Meta-analysis.

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“There is a lack of consensus on the role of selective cannabinoids for the treatment of neuropathic pain (NP). Guidelines from national and international pain societies have provided contradictory recommendations. The primary objective of this systematic review and meta-analysis (SR-MA) was to determine the analgesic efficacy and safety of selective cannabinoids compared to conventional management or placebo for chronic NP.

METHODS:

We reviewed randomized controlled trials that compared selective cannabinoids (dronabinol, nabilone, nabiximols) with conventional treatments (eg, pharmacotherapy, physical therapy, or a combination of these) or placebo in patients with chronic NP because patients with NP may be on any of these therapies or none if all standard treatments have failed to provide analgesia and or if these treatments have been associated with adverse effects. MEDLINE, EMBASE, and other major databases up to March 11, 2016, were searched. Data on scores of numerical rating scale for NP and its subtypes, central and peripheral, were meta-analyzed. The certainty of evidence was classified using the Grade of Recommendations Assessment, Development, and Evaluation approach.

RESULTS:

Eleven randomized controlled trials including 1219 patients (614 in selective cannabinoid and 605 in comparator groups) were included in this SR-MA. There was variability in the studies in quality of reporting, etiology of NP, type and dose of selective cannabinoids. Patients who received selective cannabinoids reported a significant, but clinically small, reduction in mean numerical rating scale pain scores (0-10 scale) compared with comparator groups (-0.65 points; 95% confidence interval, -1.06 to -0.23 points; P = .002, I = 60%; Grade of Recommendations Assessment, Development, and Evaluation: weak recommendation and moderate-quality evidence). Use of selective cannabinoids was also associated with improvements in quality of life and sleep with no major adverse effects.

CONCLUSIONS:

Selective cannabinoids provide a small analgesic benefit in patients with chronic NP. There was a high degree of heterogeneity among publications included in this SR-MA. Well-designed, large, randomized studies are required to better evaluate specific dosage, duration of intervention, and the effect of this intervention on physical and psychologic function.”

 https://www.ncbi.nlm.nih.gov/pubmed/28537982
http://insights.ovid.com/crossref?an=00000539-900000000-97514

Continuous Intrathecal Infusion of Cannabinoid Receptor Agonists Attenuates Nerve Ligation-Induced Pain in Rats.

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“Cannabinoid receptors (CB1R/CB2R) are known to play important roles in pain transmission.

In this study, we investigated the effects of continuous intrathecal infusion of CB1/2R agonists in the L5/6 spinal nerve ligation pain model.

Continuous intrathecal infusion of CB1/2R agonists elicits antinociception in the pain model.

The mechanisms might involve their actions on neurons and glial cells. CB2R, but not CB1R, seems to play an important role in the regulation of nerve injury-induced neuroinflammation.”

https://www.ncbi.nlm.nih.gov/pubmed/28492437

Combined cannabinoid therapy via an oromucosal spray.

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“Extensive basic science research has identified the potential therapeutic benefits of active compounds extracted from the Cannabis sativa L. plant (the cannabinoids). It is recognized that a significant proportion of patients suffering with the debilitating symptoms of pain and spasticity in multiple sclerosis or other conditions smoke cannabis despite the legal implications and stigma associated with this controlled substance. GW Pharmaceuticals have developed Sativex (GW- 1000-02), a combined cannabinoid medicine that delivers and maintains therapeutic levels of two principal cannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), via an oromucosal pump spray, that aims to minimize psychotropic side effects.”  https://www.ncbi.nlm.nih.gov/pubmed/16969427

“Sativex has proved to be well tolerated and successfully self-administered and self-titrated in both healthy volunteers and patient cohorts. Clinical assessment of this combined cannabinoid medicine has demonstrated efficacy in patients with intractable pain (chronic neuropathic pain, pain due to brachial plexus nerve injury, allodynic peripheral neuropathic pain and advanced cancer pain), rheumatoid arthritis and multiple sclerosis (bladder problems, spasticity and central pain), with no significant intoxication-like symptoms, tolerance or withdrawal syndrome.”  https://journals.prous.com/journals/servlet/xmlxsl/pk_journals.xml_summaryn_pr?p_JournalId=4&p_RefId=1021517

“Sativex(®) (nabiximols, USAN name) oromucosal spray contains the two main active constituents of Cannabis sativa, tetrahydrocannabinol and cannabidiol in a 1:1 molecular ratio, and acts as an endocannabinoid system modulator.”  https://www.ncbi.nlm.nih.gov/pubmed/21449855

“Abuse potential and psychoactive effects of δ-9-tetrahydrocannabinol and cannabidiol oromucosal spray (Sativex), a new cannabinoid medicine. Evidence to date suggests that abuse or dependence on Sativex is likely to occur in only a very small proportion of recipients.” https://www.ncbi.nlm.nih.gov/pubmed/21542664

Cannabinoid CB2 receptor ligand profiling reveals biased signalling and off-target activity

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“The cannabinoid CB2 receptor (CB2R) represents a promising therapeutic target for various forms of tissue injury and inflammatory diseases. There is a great interest in the development of selective type-2 cannabinoid receptor (CB2R) agonists as potential drug candidates for various pathophysiological conditions, which include chronic and inflammatory pain, pruritus, diabetic neuropathy and nephropathy, liver cirrhosis, and protective effects after ischaemic-reperfusion injury.” https://www.nature.com/articles/ncomms13958

“Pain relief without the high. Researchers at Leiden University led by Mario van der Stelt (Leiden Institute for Chemistry) have set ‘gold standards’ for developing new painkillers based on the medicinal effects of cannabis.”  https://www.sciencedaily.com/releases/2017/01/170104103916.htm

ScienceDaily

Antihyperalgesic Activities of Endocannabinoids in a Mouse Model of Antiretroviral-Induced Neuropathic Pain.

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“Nucleoside reverse transcriptase inhibitors (NRTIs) are the cornerstone of the antiretroviral therapy for human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). However, their use is sometimes limited by the development of a painful sensory neuropathy, which does not respond well to drugs.

Smoked cannabis has been reported in clinical trials to have efficacy in relieving painful HIV-associated sensory neuropathy.

The aim of this study was to evaluate whether the expression of endocannabinoid system molecules is altered during NRTI-induced painful neuropathy, and also whether endocannabinoids can attenuate NRTI-induced painful neuropathy.

Conclusion: These data show that ddC induces thermal hyperalgesia, which is associated with dysregulation of the mRNA expression of some endocannabinoid system molecules. The endocannabinoids AEA and 2-AG have antihyperalgesic activity, which is dependent on cannabinoid receptor and GPR55 activation. Thus, agonists of cannabinoid receptors and GPR55 could be useful therapeutic agents for the management of NRTI-induced painful sensory neuropathy.”

https://www.ncbi.nlm.nih.gov/pubmed/28373843

Effects of JWH015 in cytokine secretion in primary human keratinocytes and fibroblasts and its suitability for topical/transdermal delivery.

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“JWH015 is a cannabinoid (CB) receptor type 2 agonist that produces immunomodulatory effects. Since skin cells play a key role in inflammatory conditions and tissue repair, we investigated the ability of JWH015 to promote an anti-inflammatory and pro-wound healing phenotype in human primary skin cells.

The expression of CB1 and CB2 receptors (mRNA) and the production of pro- and anti-inflammatory factors enhanced in keratinocytes and fibroblasts following lipopolysaccharide stimulation. JWH015 reduced the concentration of major pro-inflammatory factors (IL-6 and MCP-1) and increased the concentration of a major anti-inflammatory factor (TGF-β) in lipopolysaccharide-stimulated cells.

JWH015 induced a faster scratch gap closure. These JWH015’seffects were mainly modulated through both CB1 and CB2 receptors. Topically administered JWH015 was mostly retained in the skin and displayed a sustained and low level of transdermal permeation.

Our findings suggest that targeting keratinocytes and fibroblasts with cannabinoid drugs could represent a therapeutic strategy to resolve peripheral inflammation and promote tissue repair.”

 https://www.ncbi.nlm.nih.gov/pubmed/28326930

Cannabinoids for treating inflammatory bowel diseases: where are we and where do we go?

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“Fifty years after the discovery of Δ9-tetrahydrocannabinol (THC) as the psychoactive component of Cannabis, we are assessing the possibility of translating this herb into clinical treatment of inflammatory bowel diseases (IBDs).

Here, a discussion on the problems associated with a potential treatment is given.

From first surveys and small clinical studies in patients with IBD we have learned that Cannabis is frequently used to alleviate diarrhea, abdominal pain, and loss of appetite.

Single ingredients from Cannabis, such as THC and cannabidiol, commonly described as cannabinoids, are responsible for these effects. Synthetic cannabinoid receptor agonists are also termed cannabinoids, some of which, like dronabinol and nabilone, are already available with a narcotic prescription.

Recent data on the effects of Cannabis/cannabinoids in experimental models of IBD and in clinical trials with IBD patients have been reviewed using a PubMed database search. A short background on the endocannabinoid system is also provided.

Expert commentary: Cannabinoids could be helpful for certain symptoms of IBD, but there is still a lack of clinical studies to prove efficacy, tolerability and safety of cannabinoid-based medication for IBD patients, leaving medical professionals without evidence and guidelines.”

 https://www.ncbi.nlm.nih.gov/pubmed/28276820