Effects of cannabinoid administration for pain: A meta-analysis and meta-regression.

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“Chronic pain states have resulted in an overreliance on opioid pain relievers, which can carry significant risks when used long term. As such, alternative pain treatments are increasingly desired.

Although emerging research suggests that cannabinoids have therapeutic potential regarding pain, results from studies across pain populations have been inconsistent. To provide meta-analytic clarification regarding cannabis’s impact on subjective pain, we identified studies that assessed drug-induced pain modulations under cannabinoid and corresponding placebo conditions.

Results revealed that cannabinoid administration produced a medium-to-large effect across included studies, Cohen’s d = -0.58, 95% confidence interval (CI) [-0.74, -0.43], while placebo administration produced a small-to-medium effect, Cohen’s d = -0.39, 95% CI [-0.52, -0.26]. Meta-regression revealed that cannabinoids, β = -0.43, 95% CI [-0.62, -0.24], p < .05, synthetic cannabinoids, β = -0.39, 95% CI [-0.65, -0.14], p < .05, and sample size, β = 0.01, 95% CI [0.00, 0.01], p < .05, were associated with marked pain reduction.

These outcomes suggest that cannabinoid-based pharmacotherapies may serve as effective replacement/adjunctive options regarding pain, however, additional research is warranted.”

https://www.ncbi.nlm.nih.gov/pubmed/31120281

https://psycnet.apa.org/doiLanding?doi=10.1037%2Fpha0000281

CB2 receptor deletion on myeloid cells enhanced mechanical allodynia in a mouse model of neuropathic pain.

 Scientific Reports“Neuropathic pain can develop after nerve injury, leading to a chronic condition with spontaneous pain and hyperalgesia.

Pain is typically restricted to the side of the injured nerve, but may occasionally spread to the contralateral side, a condition that is often referred to as mirror-image pain.

Mechanisms leading to mirror-image pain are not completely understood, but cannabinoid CB2 receptors have been implicated.

In this study, we use genetic mouse models to address the question if CB2 receptors on neurons or on microglia/macrophages are involved.

We conclude that CB2 receptors on microglia and macrophages, but not on neurons, modulate neuropathic pain responses.”

https://www.ncbi.nlm.nih.gov/pubmed/31097758

https://www.nature.com/articles/s41598-019-43858-4

Cannabinoid-induced relief of hypermotility in a rat model of the irritable bowel syndrome.

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“Cannabinoid-2 receptor agonists may be useful in treating intestinal motility disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/31094052

https://onlinelibrary.wiley.com/doi/abs/10.1111/nmo.13613

Diverse TRPV1 responses to cannabinoids.

 Publication Cover“Cannabinoid compounds are potential analgesics. Users of medicinal Cannabis report efficacy for pain control, clinical studies show that cannabis can be effective and opioid sparing in chronic pain, and some constituent cannabinoids have been shown to target nociceptive ion channels. Here, we explore and compare a suite of cannabinoids for their impact upon the physiology of TRPV1. The cannabinoids tested evoke differential responses in terms of kinetics of activation and inactivation. Cannabinoid activation of TRPV1 displays significant dependence on internal and external calcium levels. Cannabinoid activation of TRPV1 does not appear to induce the highly permeant, pore-dilated channel state seen with Capsaicin, even at high current amplitudes. Finally, we analyzed cannabinoid responses at nocioceptive channels other than TRPV1 (TRPV2, TRPM8 and TRPA1), and report that cannabinoids differentially activate these channels. On the basis of response activation and kinetics, state-selectivity and receptor selectivity, it may be possible to rationally design approaches to pain using single or multiple cannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/31096838

https://www.tandfonline.com/doi/full/10.1080/19336950.2019.1619436

Tetrahydrocannabinol Reduces Hapten-Driven Mast Cell Accumulation and Persistent Tactile Sensitivity in Mouse Model of Allergen-Provoked Localized Vulvodynia.

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“Vulvodynia is a remarkably prevalent chronic pain condition of unknown etiology.

Therapeutic intra-vaginal administration of Δ9-tetrahydrocannabinol (THC) reduced mast cell accumulation and tactile sensitivity.

Mast cell-targeted therapeutic strategies may therefore provide new ways to manage and treat vulvar pain potentially instigated by repeated allergenic exposures.”

https://www.ncbi.nlm.nih.gov/pubmed/31052404

https://www.mdpi.com/1422-0067/20/9/2163

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

Tetrahydrocannabinol – friend or foe? – Debate.

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“Medical THC is beneficial for various conditions (especially pain relief).”

https://www.ncbi.nlm.nih.gov/pubmed/31062643

https://www.tandfonline.com/doi/abs/10.1080/15563650.2019.1610567?journalCode=ictx20

Using Cannabis to Treat Cancer-Related Pain.

Seminars in Oncology Nursing

“OBJECTIVE: To describe which cannabinoids and terpenes are effective for treating pain.

CONCLUSION: Cannabis and cannabinoid medicines, as modulators of the endocannabinoid system, offer novel therapeutic options for the treatment of cancer-related pain, not only for patients who do not respond to conventional therapies, but also for patients who prefer to try cannabis as a first treatment option.

IMPLICATIONS FOR NURSING PRACTICE: Understanding the endocannabinoid system, cannabinoids, terpenes, routes of administration, potential drug interactions, clinical implications, and potential side effects ensures nurses can better assist patients who use cannabis for the treatment of cancer pain.”

https://www.ncbi.nlm.nih.gov/pubmed/31053395

https://www.sciencedirect.com/science/article/pii/S0749208119300609?via%3Dihub

Future Aspects for Cannabinoids in Breast Cancer Therapy.

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“Cannabinoids (CBs) from Cannabis sativa provide relief for tumor-associated symptoms (including nausea, anorexia, and neuropathic pain) in the palliative treatment of cancer patients.

Additionally, they may decelerate tumor progression in breast cancer patients.

Indeed, the psychoactive delta-9-tetrahydrocannabinol (THC), non-psychoactive cannabidiol (CBD) and other CBs inhibited disease progression in breast cancer models.

The effects of CBs on signaling pathways in cancer cells are conferred via G-protein coupled CB-receptors (CB-Rs), CB1-R and CB2-R, but also via other receptors, and in a receptor-independent way.

THC is a partial agonist for CB1-R and CB2-R; CBD is an inverse agonist for both.

In breast cancer, CB1-R expression is moderate, but CB2-R expression is high, which is related to tumor aggressiveness. CBs block cell cycle progression and cell growth and induce cancer cell apoptosis by inhibiting constitutive active pro-oncogenic signaling pathways, such as the extracellular-signal-regulated kinase pathway.

They reduce angiogenesis and tumor metastasis in animal breast cancer models. CBs are not only active against estrogen receptor-positive, but also against estrogen-resistant breast cancer cells. In human epidermal growth factor receptor 2-positive and triple-negative breast cancer cells, blocking protein kinase B- and cyclooxygenase-2 signaling via CB2-R prevents tumor progression and metastasis.

Furthermore, selective estrogen receptor modulators (SERMs), including tamoxifen, bind to CB-Rs; this process may contribute to the growth inhibitory effect of SERMs in cancer cells lacking the estrogen receptor.

In summary, CBs are already administered to breast cancer patients at advanced stages of the disease, but they might also be effective at earlier stages to decelerate tumor progression.”

Potential for endocannabinoid system modulation in ocular pain and inflammation: filling the gaps in current pharmacological options

Neuronal Signaling

“Challenges in the management of ocular pain are an underappreciated topic. Currently available therapeutics lack both efficacy and clear guidelines for their use, with many also possessing unacceptable side effects. Promising novel agents would offer analgesic, anti-inflammatory, and possibly neuroprotective actions; have favorable ocular safety profiles; and show potential in managing neuropathic pain.

Growing evidence supports a link between the endocannabinoid system (ECS) and a range of physiological and disease processes, notably those involving inflammation and pain. Both preclinical and clinical data suggest analgesic and anti-inflammatory actions of cannabinoids and ECS-modifying drugs in chronic pain conditions, including those of neuropathic origin.

The ECS is present ubiquitously through the body, including a range of ocular tissues, and represents a promising target in the treatment of several physiological and pathophysiologic processes in the eye including, but not limited to, pain, inflammation, and neuronal damage. ”

http://www.neuronalsignaling.org/content/2/4/NS20170144

Δ9-tetrahydrocannabinol attenuates oxycodone self-administration under extended access conditions.

Neuropharmacology

“Growing nonmedical use of prescription opioids is a global problem, motivating research on ways to reduce use and combat addiction.

Medical cannabis (“medical marijuana”) legalization has been associated epidemiologically with reduced opioid harms and cannabinoids have been shown to modulate effects of opioids in animal models.

This study was conducted to determine if Δ9-tetrahydrocannabinol (THC) enhances the behavioral effects of oxycodone.

Together these data demonstrate additive effects of THC and oxycodone and suggest the potential use of THC to enhance therapeutic efficacy, and to reduce the abuse, of opioids.”

https://www.ncbi.nlm.nih.gov/pubmed/30980837

“Δ9-tetrahydrocannabinol (THC) enhances the antinociceptive effects of oxycodone. Vaporized and injected THC reduces oxycodone self-administration. Cannabinoids may reduce opioid use for analgesia. Cannabinoids may reduce nonmedical opioid use.”  

https://www.sciencedirect.com/science/article/pii/S0028390819301212?via%3Dihub