Cannabis in Pain Treatment: Clinical & Research Considerations.

“Cannabinoids show promise as therapeutic agents, particularly as analgesics, but their development and clinical use has been complicated by recognition of their botanical source, cannabis, as a substance of misuse. While research into endogenous cannabinoid systems and potential cannabinoid pharmaceuticals is slowly increasing, there has been intense societal interest in making herbal (plant) cannabis available for medicinal use; 23 U.S. States and all Canadian provinces currently permit use in some clinical contexts. Whether or not individual professionals support the clinical use of herbal cannabis, all clinicians will encounter patients who elect to use it and therefore need to be prepared to advise them on cannabis-related clinical issues despite limited evidence to guide care. Expanded research on cannabis is needed both to better determine the individual and public health effects of increasing use of herbal cannabis and to advance understanding of the pharmaceutical potential of cannabinoids as medications. This paper reviews clinical, research and policy issues related to herbal cannabis in order to support clinicians in thoughtfully advising and caring for patients who use cannabis and it examines obstacles and opportunities to expand research on the health effects of herbal cannabis and cannabinoids.

PERSPECTIVE:

Herbal cannabis is increasingly available for clinical use in the U.S despite continuing controversies over its efficacy and safety. This paper explores important considerations in the use of plant Cannabis to better prepare clinicians to care for patients who use it and to identify needed directions for research.”

http://www.ncbi.nlm.nih.gov/pubmed/26961090

PnPP-19, a spider toxin analogue, induces peripheral antinociception through opioid and cannabinoid receptors and inhibition of Neutral endopeptidase.

“The synthetic peptide PnPP-19 has been studied as a new drug candidate to treat erectile dysfunction. However, PnTx2-6, the spider toxin from which the peptide was designed, induces hyperalgesia. Therefore, we intended to investigate the role of PnPP-19 in the nociceptive pathway.

Antinociception induced by PnPP-19 might involve the inhibition of NEP and activation of CB1 , μ- and δ-opioid receptors. Our data provide a comprehension of the antinociceptive effect induced by PnPP-19 and it should be useful as a new antinociceptive drug candidate.”

http://www.ncbi.nlm.nih.gov/pubmed/26947933

Combined treatment with morphine and Δ9-tetrahydrocannibinol (THC) in rhesus monkeys: antinociceptive tolerance and withdrawal.

“Opioid receptor agonists are effective for treating pain; however, tolerance and dependence can develop with repeated treatment. Combining opioids with cannabinoids can enhance their analgesic potency…

These results demonstrate that antinociceptive tolerance is greater during treatment with the mixture, and although treatment conditions were sufficient for dependence to development on morphine, withdrawal was not markedly altered by concurrent treatment with THC.

Thus, THC can enhance some (antinociception, tolerance) but not all (dependence) effects of morphine.”

http://www.ncbi.nlm.nih.gov/pubmed/26937020

Nabilone for the Management of Pain.

“Nabilone, a synthetic cannabinoid, is approved in many countries including, but not limited to, Canada, the United States, Mexico, and the United Kingdom for the treatment of severe nausea and vomiting associated with chemotherapy. Clinical evidence is emerging for its use in managing pain conditions with different etiologies. We review the efficacy and safety of nabilone for various types of pain as well as its abuse potential, precautions and contraindications, and drug interactions; summarize pertinent clinical practice guidelines; and provide recommendations for dosing, monitoring, and patient education.

Nabilone was most commonly used as adjunctive therapy and led to small but significant reductions in pain. The most common adverse drug reactions included euphoria, drowsiness, and dizziness. Nabilone was rarely associated with severe adverse drug reactions requiring drug discontinuation, and the likelihood of abuse was thought to be low. Although the optimal role of nabilone in the management of pain is yet to be determined, certain clinical practice guidelines consider nabilone as a third-line agent.”

http://www.ncbi.nlm.nih.gov/pubmed/26923810

The Effect of Medicinal Cannabis on Pain and Quality of Life Outcomes in Chronic Pain: A Prospective Open-label Study.

“The objective of this prospective, open-label study was to determine the long-term effect of medicinal cannabis treatment on pain and functional outcomes in subjects with treatment-resistant chronic pain.

The treatment of chronic pain with medicinal cannabis in this open-label, prospective cohort resulted in improved pain and functional outcomes, and significant reduction in opioid use.

The results suggest long-term benefit of cannabis treatment in this group of patients…”

http://www.ncbi.nlm.nih.gov/pubmed/26889611

http://www.thctotalhealthcare.com/category/pain-2/

Development and Pharmacological Characterization of Selective Blockers of 2-Arachidonoyl Glycerol Degradation with Efficacy in Rodent Models of Multiple Sclerosis and Pain.

“We report the discovery of compound 4a, a potent β-lactam-based monoacylglycerol lipase (MGL) inhibitor characterized by an irreversible and stereoselective mechanism of action, high membrane permeability, high brain penetration evaluated using a human in vitro blood brain barrier model, high selectivity in binding and affinity-based proteomic profiling assays, and low in vitro toxicity.

Mode-of-action studies demonstrate that 4a, by blocking MGL, increases 2-arachidonoylglycerol, and behaves as cannabinoid (CB1/CB2) receptor indirect agonist.

Administration of 4a in mice suffering from experimental autoimmune encephalitis ameliorates the severity of the clinical symptoms in a CB1/CB2-dependent manner. Moreover, 4a produced analgesic effects in a rodent model of acute inflammatory pain, which was antagonized by CB1 and CB2 receptor antagonists/inverse agonists. 4a also relieves the neuropathic hypersensitivity induced by oxaliplatin.

Given these evidences, 4a, as MGL selective inhibitor, could represent a valuable lead for the future development of therapeutic options for multiple sclerosis and chronic pain.”

http://www.ncbi.nlm.nih.gov/pubmed/26888301

β-caryophyllene, a dietary cannabinoid, complexed with β-cyclodextrin produced anti-hyperalgesic effect involving the inhibition of Fos expression in superficial dorsal horn.

“Evaluate the anti-hyperalgesic effect of the complex containing β-caryophyllene (βCP) and β-cyclodextrin (βCD) in a non-inflammatory chronic muscle pain mice model and investigated its action on superficial dorsal horn of the lumbar spinal cord.

The characterization tests indicated that βCP were efficiently incorporated into βCD. The oral treatment with βCP-βCD, at all doses tested, produced a significant reduction on mechanical hyperalgesia and a significant increase in muscle withdrawal thresholds, without produce any alteration in force. In addition, βCP-βCD was able to significantly decrease Fos expression in the superficial dorsal horn.

SIGNIFICANCE:

Thus, βCP-βCD attenuates the non-inflammatory chronic muscle pain in mice and inhibits the Fos expression in the lumbar spinal cord.”

http://www.ncbi.nlm.nih.gov/pubmed/26883973

“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

“β (beta)-cyclodextrin: 7-membered sugar ring molecule”  https://en.wikipedia.org/wiki/Cyclodextrin

Medical cannabis: considerations for the anesthesiologist and pain physician.

“New regulations are in place at the federal and provincial levels in Canada regarding the way medical cannabis is to be controlled. We present them together with guidance for the safe use of medical cannabis and recent clinical trials on cannabis and pain.

Health Canada has approved a new regulation on medical marijuana/cannabis, the Marihuana for Medical Purposes Regulations: The production of medical cannabis by individuals is illegal. Health Canada, however, has licensed authorized producers across the country, limiting the production to specific licenses of certain cannabis products. There are currently 26 authorized licensed producers from seven Canadian provinces offering more than 200 strains of marijuana.

We provide guidance for the safe use of medical cannabis.

The recent literature indicates that currently available cannabinoids are modestly effective analgesics that provide a safe, reasonable therapeutic option for managing chronic non-cancer-related pain.

The science of medical cannabis and the need for education of healthcare professionals and patients require continued effort. Although cannabinoids work to decrease pain, there is still a need to confirm these beneficial effects clinically and to exploit them with acceptable benefit-to-risk ratios.”

http://www.ncbi.nlm.nih.gov/pubmed/26850063

[Efficacy, tolerability and safety of cannabinoids for chronic neuropathic pain : A systematic review of randomized controlled studies].

“Recently published systematic reviews came to different conclusions with respect to the efficacy, tolerability and safety of cannabinoids for treatment of chronic neuropathic pain.

Cannabinoids were marginally superior to placebo in terms of efficacy and inferior in terms of tolerability.

Cannabinoids and placebo did not differ in terms of safety during the study period.

Short-term and intermediate-term therapy with cannabinoids can be considered in selected patients with chronic neuropathic pain after failure of first-line and second-line therapies.”

http://www.ncbi.nlm.nih.gov/pubmed/26830780

http://www.thctotalhealthcare.com/category/neuropathic-pain/

Up-regulation of immunomodulatory effects of mouse bone-marrow derived mesenchymal stem cells by tetrahydrocannabinol pre-treatment involving cannabinoid receptor CB2.

“Chronic pain is commonly and closely correlated with inflammation.

Both cannabinoid signaling and mesenchymal stem cells (MSCs) have been demonstrated to reduce inflammatory pain.

Although cannabinoid signaling is essential for mesenchymal stem cell survival and differentiation, little is known about its role in modulatory effect of MSCs on inflammation and pain sensitivity. Here we showed that mouse bone-marrow derived MSCs (BM-MSCs) expressed both cannabinoid receptor type 1 and 2 (CB1 and CB2). CB2 expression level in BM-MSCs increased with their maturation.

In addition, we found that tetrahydrocannabinol (THC) activated CB2 receptor and ERK signaling, consequently enhancing the modulation of MSCs on inflammation-associated cytokine release from lipopolysaccharides-stimulated microglia.

Consistent with in vitro data, THC pretreatment enhanced the immunomodulatory effects of BM-MSC on thermal hyperalgesia and mechanical allodynia in chronic constriction injury model, by decreasing the release of pro-inflammation cytokines.

Our study revealed the crucial role of THC in promoting the immunomodulatory effects of MSCs and proposed a new strategy to alleviate pain based on stem cells therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/26824325