Tag Archives: analgesic

Opioid-sparing Effect of Cannabinoids: A Systematic Review and Meta-analysis.

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“Cannabinoids, when co-administered with opioids, may enable reduced opioid doses without loss of analgesic efficacy (ie an opioid-sparing effect). The aim of this study was to conduct a systematic review to determine the opioid-sparing potential of cannabinoids.

Eligible studies included pre-clinical and clinical studies for which the outcome was either analgesia or opioid dose requirements. Clinical studies included controlled studies and case series. We searched Scopus, Cochrane Database of Systematic Reviews, Medline, and Embase. Nineteen pre-clinical and nine clinical studies met the search criteria. Seventeen of the 19 pre-clinical studies provided evidence of synergistic effects from opioid and cannabinoid co-administration. Our meta-analysis of pre-clinical studies indicated that the median effective dose (ED50) of morphine administered in combination with delta-9-tetrahydrocannabinol (delta-9-THC) is 3.6 times lower (95% CI 1.95, 6.76; n=6) than the ED50 of morphine alone. In addition, the ED50 for codeine administered in combination with delta-9-THC was 9.5 times lower (95% CI 1.6, 57.5, n=2) than the ED50 of codeine alone. One case series (n=3) provided very low-quality evidence of a reduction in opioid requirements with cannabinoid co-administration. Larger controlled clinical studies showed some clinical benefits of cannabinoids; however, opioid dose changes were rarely reported and mixed findings were observed for analgesia.

In summary, pre-clinical studies provide robust evidence of the opioid-sparing effect of cannabinoids, while one of the nine clinical studies identified provided very low-quality evidence of such an effect. Prospective high-quality controlled clinical trials are required to determine the opioid-sparing effect of cannabinoids.”

https://www.ncbi.nlm.nih.gov/pubmed/28327548

Fatty-acid-binding protein inhibition produces analgesic effects through peripheral and central mechanisms.

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“Fatty-acid-binding proteins (FABPs) are intracellular carriers for endocannabinoids, N-acylethanolamines, and related lipids. Previous work indicates that systemically administered FABP5 inhibitors produce analgesia in models of inflammatory pain. It is currently not known whether FABP inhibitors exert their effects through peripheral or central mechanisms. Here, we examined FABP5 distribution in dorsal root ganglia and spinal cord and examined the analgesic effects of peripherally and centrally administered FABP5 inhibitors.

Results: Immunofluorescence revealed robust expression of FABP5 in lumbar dorsal root ganglia. FABP5 was distributed in peptidergic calcitonin gene-related peptide-expressing dorsal root ganglia and non-peptidergic isolectin B4-expressing dorsal root ganglia. In addition, the majority of dorsal root ganglia expressing FABP5 also expressed transient receptor potential vanilloid 1 (TRPV1) and peripherin, a marker of nociceptive fibers. Intraplantar administration of FABP5 inhibitors reduced thermal and mechanical hyperalgesia in the complete Freund’s adjuvant model of chronic inflammatory pain. In contrast to its robust expression in dorsal root ganglia, FABP5 was sparsely distributed in the lumbar spinal cord and intrathecal administration of FABP inhibitor did not confer analgesic effects. Administration of FABP inhibitor via the intracerebroventricular (i.c.v.) route reduced thermal hyperalgesia. Antagonists of peroxisome proliferator-activated receptor alpha blocked the analgesic effects of peripherally and i.c.v. administered FABP inhibitor while antagonism of cannabinoid receptor 1 blocked the effects of peripheral FABP inhibition and a TRPV1 antagonist blocked the effects of i.c.v. administered inhibitor. Although FABP5 and TRPV1 were co-expressed in the periaqueductal gray region of the brain, which is known to modulate pain, knockdown of FABP5 in the periaqueductal gray using adeno-associated viruses and pharmacological FABP5 inhibition did not produce analgesic effects.

Conclusions: This study demonstrates that FABP5 is highly expressed in nociceptive dorsal root ganglia neurons and FABP inhibitors exert peripheral and supraspinal analgesic effects. This indicates that peripherally restricted FABP inhibitors may serve as a new class of analgesic and anti-inflammatory agents.”

https://www.ncbi.nlm.nih.gov/pubmed/28326944

Cannabis Reduces Opioid Dose in the Treatment of Chronic Non-Cancer Pain

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“Cannabinoids block pain responses in virtually every laboratory pain model tested.

In models of acute or physiological pain, cannabinoids are highly effective against thermal, mechanical, and chemical pain, and are comparable to opioids in potency and efficacy.1 In models of chronic pain, cannabinoids exhibit efficacy in the modulation of both inflammatory2 and neuropathic pain.3

Recent reviews describe an endogenous cannabinoid system involved in pain modulation that produces analgesia through the same brainstem circuitry involved in opioid analgesia.1., 4., 5., 6. Although co-administration of Δ-9-tetrahydrocannabinol (THC) with μ opioid agonists can potentiate the antinociceptive effects of each agent, an opioid is not required for cannabinoid analgesia.5., 6. Co-administration of a cannabinoid may lead to a lower opioid requirement. In an N-of-1 trial, oral THC reduced the pain of familial Mediterranean fever such that the use of breakthrough opioid for pain relief decreased significantly.7

Recently, in Canada, the Medical Marijuana Access Program allows patients to apply to Health Canada for access to dried cannabis for medicinal purposes. Although smoked cannabis is not an ideal delivery system, it is efficient and results in plasma concentration curves parallel to those seen after intravenous administration.8 We present three patients who used small doses of smoked marijuana in combination with an opioid.

These cases are consistent with preclinical work demonstrating that cannabinoids exhibit analgesic effects and may potentiate the antinociceptive effects of opioids. These patients were able to decrease the dose of opioid by 60–100% as compared to before the regular use of smoked marijuana. With the introduction of smoked marijuana, each patient reported better pain control.

Unfortunately, the source of smoked marijuana used by patients, and the percentage of THC in it, is unknown. All patients reported previous exposure to cannabis at some time in their lives before the onset of their pain, and the relevance of this experience also is unknown. Standardized measures of pain were not used, and the information presented was based on the patients’ verbal report when they presented for follow-up appointments at the Pain Management Unit. Nonetheless, these cases suggest that further research regarding the role of cannabinoids as analgesics and the combination of cannabinoids with opioids in the control of pain is needed.”

http://www.jpsmjournal.com/article/S0885-3924(03)00142-8/fulltext

Cannabis for Pain and Headaches: Primer.

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“Marijuana has been used both medicinally and recreationally since ancient times and interest in its compounds for pain relief has increased in recent years. The identification of our own intrinsic, endocannabinoid system has laid the foundation for further research.

Synthetic cannabinoids are being developed and synthesized from the marijuana plant such as dronabinol and nabilone. The US Food and Drug Administration approved the use of dronabinol and nabilone for chemotherapy-associated nausea and vomiting and HIV (Human Immunodeficiency Virus) wasting. Nabiximols is a cannabis extract that is approved for the treatment of spasticity and intractable pain in Canada and the UK. Further clinical trials are studying the effect of marijuana extracts for seizure disorders.

Phytocannabinoids have been identified as key compounds involved in analgesia and anti-inflammatory effects.  Other compounds found in cannabis such as flavonoids and terpenes are also being investigated as to their individual or synergistic effects.

This article will review relevant literature regarding medical use of marijuana and cannabinoid pharmaceuticals with an emphasis on pain and headaches.”

https://www.ncbi.nlm.nih.gov/pubmed/28281107

Medical marijuana policies and hospitalizations related to marijuana and opioid pain reliever.

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“Twenty-eight states in the U.S have legalized medical marijuana, yet its impacts on severe health consequences such as hospitalizations remain unknown. Meanwhile, the prevalence of opioid pain reliever (OPR) use and outcomes has increased dramatically. Recent studies suggested unintended impacts of legalizing medical marijuana on OPR, but the evidence is still limited. This study examined the associations between state medical marijuana policies and hospitalizations related to marijuana and OPR.

Hospitalizations related to marijuana and OPR increased sharply by 300% on average in all states. Medical marijuana legalization was associated with 23% (p=0.008) and 13% (p=0.025) reductions in hospitalizations related to opioid dependence or abuse and OPR overdose, respectively; lagged effects were observed after policy implementation. The operation of medical marijuana dispensaries had no independent impacts on OPR-related hospitalizations. Medical marijuana polices had no associations with marijuana-related hospitalizations.

Medical marijuana policies were significantly associated with reduced OPR-related hospitalizations but had no associations with marijuana-related hospitalizations. Given the epidemic of problematic use of OPR, future investigation is needed to explore the causal pathways of these findings.”

https://www.ncbi.nlm.nih.gov/pubmed/28259087

Cannabinoid signaling in health and disease.

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“Cannabis sativa has long been used for medicinal purposes.

To improve safety and efficacy, compounds from C. sativa were purified or synthesized and named under an umbrella group as cannabinoids.

Currently, several cannabinoids may be prescribed in Canada for a variety of indications such as nausea and pain.

More recently, an increasing number of reports suggest other salutary effects associated with endogenous cannabinoid signaling including cardioprotection.

The therapeutic potential of cannabinoids is therefore extended; however, evidence is limited and mechanisms remain unclear.

In addition, the use of cannabinoids clinically has been hindered due to pronounced psychoactive side effects.

This review provides an overview on the endocannabinoid system, including known physiological roles, and conditions in which cannabinoid receptor signaling has been implicated.”

 https://www.ncbi.nlm.nih.gov/pubmed/28263083

Cannabinoid receptor 2 agonist attenuates pain related behavior in rats with chronic alcohol/high fat diet induced pancreatitis

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“Chronic Pancreatitis (CP) is a complex and multifactorial syndrome. Many contributing factors result in development of dysfunctional pain in a significant number of patients. Drugs developed to treat a variety of pain states fall short of providing effective analgesia for patients with chronic pancreatitis, often providing minimal to partial pain relief over time with significant side effects.

Recently, availability of selective pharmacological tools has enabled great advances in our knowledge of the role of the cannabinoid receptors in pathophysiology. In particular, cannabinoid receptor 2 (CB2) has emerged as an attractive target for management of chronic pain, as demonstrated in several studies with inflammatory and neuropathic preclinical pain models. In this study, the analgesic efficacy of a novel, highly selective CB2 receptor agonist, LY3038404 HCl, is investigated in a chronic pancreatitis pain model, induced with an alcohol/high fat (AHF) diet.

LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties without effects on higher brain function. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for visceral inflammation and pain management.

The major finding of the present study is that LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties. No effects on higher brain functions were observed including the diminished fear responses induced by the alcohol diet. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for pancreas protection and pain management.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242547/

Cannabinoids Ameliorate Pain and Reduce Disease Pathology in Cerulein-Induced Acute Pancreatitis

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“The endocannabinoid system has been identified as a major regulator of physiological and pathological processes, such as pain, inflammation, cell growth, cell death, and as a regulator of diverse gastrointestinal functions, such as intestinal motility and secretion.

Although cannabinoid-induced analgesia was initially primarily attributed to the activation of cannabinoid receptor 1 (CB1) in the nervous system, later studies demonstrated a contribution of cannabinoid receptor 2 (CB2), localized peripherally on immune cells as well as in the nervous system.

A complex interplay between endogenously released cannabinoids, such as anandamide or 2-arachidonoylglycerol, and their receptors both on inflammatory cells and neurons is involved in modulation of inflammatory pain.

In this article, we demonstrate the in vivo significance and therapeutic potential of cannabinoids in inflammation and pain associated with pancreatitis using human specimens and mouse models as test systems.

Our results are more in line with a recent study reporting a protective role for the endogenous cannabinoid system against colonic inflammation in a mouse model of experimental colitis.

Consistent with the above, we now show that acute pancreatitis, a visceral inflammatory disease in humans, is associated with an activation of the endocannabinoid system.

In humans, acute pancreatitis is associated with up-regulation of ligands as well as receptors of the endocannabinoid system in the pancreas. Furthermore, our results suggest a therapeutic potential for cannabinoids in abolishing pain associated with acute pancreatitis and in partially reducing inflammation and disease pathology in the absence of adverse side effects.

Because management of visceral inflammatory diseases should ideally include antinociceptive as well as anti-inflammatory components, our results lay a basis for testing the therapeutic value of cannabinoids as supplements to conventional analgesic therapy.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2268094/

Gut-brain axis: Role of lipids in the regulation of inflammation, pain and CNS diseases.

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“The human gut is a composite anaerobic environment with a large, diverse and dynamic enteric microbiota, represented by more than 100 trillion microorganisms, including at least 1000 distinct species. The discovery that a different microbial composition can influence behavior and cognition, and in turn the nervous system can indirectly influence enteric microbiota composition, has significantly contributed to establish the well-accepted concept of gut-brain axis.

This hypothesis is supported by several evidence showing mutual mechanisms, which involve the vague nerve, the immune system, the hypothalamic-pituitary-adrenal (HPA) axis modulation and the bacteria-derived metabolites. Many studies have focused on delineating a role for this axis in health and disease, ranging from stress-related disorders such as depression, anxiety and irritable bowel syndrome (IBS) to neurodevelopmental disorders, such as autism, and to neurodegenerative diseases, such as Parkinson Disease, Alzheimer Disease etc.

Based on this background, and considering the relevance of alteration of the symbiotic state between host and microbiota, this review focuses on the role and the involvement of bioactive lipids, such as the N-acylethanolamine (NAE) family whose main members are N-arachidonoylethanolamine (AEA), palmitoylethanolamide (PEA) and oleoilethanolamide (OEA), and short chain fatty acids (SCFAs), such as butyrate, belonging to a large group of bioactive lipids able to modulate peripheral and central pathologic processes.

It is well established their effective role in inflammation, acute and chronic pain, obesity and central nervous system diseases. It has been shown a possible correlation between these lipids and gut microbiota through different mechanisms.

Indeed, systemic administration of specific bacteria can reduce abdominal pain through the involvement of cannabinoid receptor 1 in rat; on the other hand, PEA reduces inflammation markers in a murine model of inflammatory bowel disease (IBD), and butyrate, producted by gut microbiota, is effective in reducing inflammation and pain in irritable bowel syndrome and IBD animal models.

In this review, we underline the relationship among inflammation, pain, microbiota and the different lipids, focusing on a possible involvement of NAEs and SCFAs in the gut-brain axis and their role in central nervous system diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/28215162

Cannabis: old medicine with new promise for neurological disorders.

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“Marijuana is a complex substance containing over 60 different forms of cannabinoids, the active ingredients. Cannabinoids are now known to have the capacity for neuromodulation, via direct, receptor-based mechanisms at numerous levels within the nervoussystem. These have therapeutic properties that may be applicable to the treatment of neurological disorders; including anti-oxidative, neuroprotective, analgesic and anti-inflammatory actions; immunomodulation, modulation of glial cells and tumor growth regulation. This article reviews the emerging research on the physiological mechanisms of endogenous and exogenous cannabinoids in the context of neurological disease.” https://www.ncbi.nlm.nih.gov/pubmed/12054093

“Cannabinoids in the Treatment of Neurological Disorders” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4604187/