Modulating the endocannabinoid pathway as treatment for peripheral neuropathic pain: a selected review of preclinical studies.

“Chemotherapy-induced neuropathic pain is a distressing and commonly occurring side effect of many commonly used chemotherapeutic agents, which in some cases may prevent cancer patients from being able to complete their treatment.

Cannabinoid based therapies have the potential to manage or even prevent pain associated with this syndrome.

Pre-clinical animal studies that investigate the modulation of the endocannabinoid system (endogenous cannabinoid pathway) are being conducted to better understand the mechanisms behind this phenomenon.

Five recent pre-clinical studies identified from Medline published between 2013 and 2016 were selected for review. All studies evaluated the effect of small-molecule agonists or antagonists on components of the endocannabinoid system in rats or mice, using cisplatin or paclitax-el-induced allodynia as a model of chemotherapy-induced neuropathic pain. Activation of the cannabinoid receptor-2 (CB-2) receptor by AM1710 blocked paclitaxel-induced mechanical and cold allodynia in one study.

Four studies investigating the activation of both cannabinoid receptor-1 (CB-1) and CB-2 receptors by dual-agonists (WIN55,21 and CP55,940), or by the introduction of inhibitors of endocannabinoid metabolisers (URB597, URB937, JZL184, and SA-57) showed reduction of chemotherapy-induced al-lodynia. In addition, their results suggest that anti-allodynic effects may also be mediated by additional receptors, including TRPV1 and 5-hydroxytryptamine (5-HT1A).

Pre-clinical studies demon-strate that the activation of endocannabinoid CB-1 or CB-2 receptors produces physiological effects in animal models, namely the reduction of chemotherapy-induced allodynia. These studies also provide in-sight into the biological mechanism behind the therapeutic utility of cannabis compounds in managing chemotherapy-induced neuropathic pain, and provide a basis for the conduct of future clinical studies in patients of this population.”

Associations between medical cannabis and prescription opioid use in chronic pain patients: A preliminary cohort study.

Image result for plos one

“Current levels and dangers of opioid use in the U.S. warrant the investigation of harm-reducing treatment alternatives.

PURPOSE:

A preliminary, historical, cohort study was used to examine the association between enrollment in the New Mexico Medical Cannabis Program (MCP) and opioid prescription use.

RESULTS:

By the end of the 21 month observation period, MCP enrollment was associated with 17.27 higher age- and gender-adjusted odds of ceasing opioid prescriptions (CI 1.89 to 157.36, p = 0.012), 5.12 higher odds of reducing daily prescription opioid dosages (CI 1.56 to 16.88, p = 0.007), and a 47 percentage point reduction in daily opioid dosages relative to a mean change of positive 10.4 percentage points in the comparison group (CI -90.68 to -3.59, p = 0.034). The monthly trend in opioid prescriptions over time was negative among MCP patients (-0.64mg IV morphine, CI -1.10 to -0.18, p = 0.008), but not statistically different from zero in the comparison group (0.18mg IV morphine, CI -0.02 to 0.39, p = 0.081). Survey responses indicated improvements in pain reduction, quality of life, social life, activity levels, and concentration, and few side effects from using cannabis one year after enrollment in the MCP (ps<0.001).

CONCLUSIONS:

The clinically and statistically significant evidence of an association between MCP enrollment and opioid prescription cessation and reductions and improved quality of life warrants further investigations on cannabis as a potential alternative to prescription opioids for treating chronic pain.” https://www.ncbi.nlm.nih.gov/pubmed/29145417

“In summary, if cannabis can serve as an alternative to prescription opioids for at least some patients, legislators and the medical community may want to consider medical cannabis programs as a potential tool for combating the current opioid epidemic.”   http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187795

“Study finds medical cannabis is effective at reducing opioid addiction”  http://news.unm.edu/news/study-finds-medical-cannabis-is-effective-at-reducing-opioid-addiction

Availability and approval of cannabis-based medicines for chronic pain management and palliative/supportive care in Europe: A survey of the status in the chapters of the European Pain Federation.

European Journal of Pain

“There is considerable public and political interest in the use of cannabis products for medical purposes.

METHODS:

The task force of the European Pain Federation (EFIC) conducted a survey with its national chapters representatives on the status of approval of all types of cannabis-based medicines, the covering of costs and the availability of a position paper of a national medical association on the use of medical cannabis for chronic pain and for symptom control in palliative/supportive care.

RESULTS:

Thirty-one out of 37 contacted councillors responded. Plant-derived tetrahydrocannabinol/cannabidiol (THC/CBD) oromucosal spray is approved for spasticity in multiple sclerosis refractory to conventional treatment in 21 EFIC chapters. Plant-derived THC (dronabinol) is approved for some palliative care conditions in four EFIC chapters. Synthetic THC analogue (nabilone) is approved for chemotherapy-associated nausea and vomiting refractory to conventional treatment in four EFIC chapters’. Eight EFIC chapters’ countries have an exceptional and six chapters an expanded access programme for medical cannabis. German and Israeli pain societies recommend the use of cannabis-based medicines as third-line drug therapies for chronic pain within a multicomponent approach. Conversely, the German medical association and a team of finish experts and officials do not recommend the prescription of medical cannabis due to the lack of high-quality evidence of efficacy and the potential harms.

CONCLUSIONS:

There are marked differences between the countries represented in EFIC in the approval and availability of cannabis-based products for medical use. EFIC countries are encouraged to collaborate with the European Medicines Agency to publish a common document on cannabis-based medicines.

SIGNIFICANCE:

There are striking differences between European countries in the availability of plant-derived and synthetic cannabinoids and of medical cannabis for pain management and for symptom control in palliative care and in the covering of costs by health insurance companies or state social security systems.”

https://www.ncbi.nlm.nih.gov/pubmed/29134767

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1147/abstract

Cannabinoids offer alternatives to opioids for pain relief, experts say.

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“Alternatives to opioids can be used alone or in combination with opioids for pain relief, to help prevent medical exposure to narcotics being an entry point to misuse, said experts at a medical education forum in Washington, DC on 3 November.

Endocannabinoid compounds found in marijuana can greatly enhance the potency of opioids in relieving pain.

The synergy from using these drugs together can result in more effective pain relief from lower doses of opioids,”

https://www.ncbi.nlm.nih.gov/pubmed/29113969

http://www.bmj.com/content/359/bmj.j5140.full

Medical cannabis for the treatment of chronic pain and other disorders: misconceptions and facts.

Home

“Recently, many countries have enacted new cannabis policies, including decriminalization of cannabis possession, medical cannabis legalization, and legalization of recreational cannabis.  In this context, patients and their physicians have had an increasing number of conversations about the risks and benefits of cannabis.  While cannabis and cannabinoids continue to be evaluated as pharmacotherapy for medical conditions, currently, the best evidence exists for the following medical conditions: chronic pain, neuropathic pain, and spasticity resulting from multiple sclerosis.  We also reviewed the current state of evidence for cannabis and cannabinoids for a number of other medical conditions while addressing the potential acute and chronic effects of cannabis use, which are issues that physicians must consider before making an official recommendation on the use of medical cannabis to a patient.  As patient requests for medical cannabis increase, physicians must become knowledgeable on the science of medical cannabis and open to a discussion about why the patient feels that medical cannabis may be helpful to them.”

https://www.ncbi.nlm.nih.gov/pubmed/29067992

http://pamw.pl/en/issue/article/29067992

Efficacy, tolerability and safety of cannabis-based medicines for chronic pain management – An overview of systematic reviews.

European Journal of Pain

“Medicinal cannabis has already entered mainstream medicine in some countries.

Cannabis-based medicines undoubtedly enrich the possibilities of drug treatment of chronic pain conditions.

It remains the responsibility of the health care community to continue to pursue rigorous study of cannabis-based medicines to provide evidence that meets the standard of 21st century clinical care.”

https://www.ncbi.nlm.nih.gov/pubmed/29034533

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1118/abstract

Cannabis for the Treatment of Chronic Pain in the Era of an Opioid Epidemic: A Symposium-Based Review of Sociomedical Science.

Pain Medicine

“This manuscript reviews medical literature published pertaining to the management of chronic pain with medical marijuana therapy (MMJ), with an emphasis on the social, medical, and legal aspects of therapy.

CONCLUSIONS:

Increasing interest in MMJ for chronic pain underscores a need for primary care and pain physicians to better understand the indications and evidence for its use free from cultural bias. Given a lack of full conclusive clinical utility, continued research is needed to better understand how to best utilize MMJ therapy for the treatment of chronic pain.”

https://www.ncbi.nlm.nih.gov/pubmed/29016917

https://academic.oup.com/painmedicine/article-abstract/doi/10.1093/pm/pnx143/3964518/Cannabis-for-the-Treatment-of-Chronic-Pain-in-the?redirectedFrom=fulltext

Cannabis and Cannabinoids for Chronic Pain.

Current Rheumatology Reports

“The purpose of this study was to provide the most up-to-date scientific evidence of the potential analgesic effects, or lack thereof, of the marijuana plant (cannabis) or cannabinoids, and of safety or tolerability of their long-term use.

RECENT FINDINGS:

We found that inhaled (smoked or vaporized) cannabis is consistently effective in reducing chronic non-cancer pain.

Oral cannabinoids seem to improve some aspects of chronic pain (sleep and general quality of life), or cancer chronic pain, but they do not seem effective in acute postoperative pain, abdominal chronic pain, or rheumatoid pain.

The available literature shows that inhaled cannabis seems to be more tolerable and predictable than oral cannabinoids. Cannabis or cannabinoids are not universally effective for pain. Continued research on cannabis constituents and improving bioavailability for oral cannabinoids is needed. Other aspects of pain management in patients using cannabis require further open discussion: concomitant opioid use, medical vs. recreational cannabis, abuse potential, etc.”

Is cannabis an effective treatment for joint pain?

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“Cannabis has been used to treat pain for thousands of years.

However, since the early part of the 20th century, laws restricting cannabis use have limited its evaluation using modern scientific criteria. Over the last decade, the situation has started to change because of the increased availability of cannabis in the United States for either medical or recreational purposes, making it important to provide the public with accurate information as to the effectiveness of the drug for joint pain among other indications.

The major psychotropic component of cannabis is Δ9-tetrahydrocannabinol (THC), one of some 120 naturally occurring phytocannabinoids. Cannabidiol (CBD) is another molecule found in herbal cannabis in large amounts. Although CBD does not produce psychotropic effects, it has been shown to produce a variety of pharmacological effects. Hence, the overall effects of herbal cannabis represent the collective activity of THC, CBD and a number of minor components.

The action of THC is mediated by two major G-protein coupled receptors, cannabinoid receptor type 1 (CB1) and CB2, and recent work has suggested that other targets may also exist. Arachidonic acid derived endocannabinoids are the normal physiological activators of the two cannabinoid receptors.

Natural phytocannabinoids and synthetic derivatives have produced clear activity in a variety of models of joint pain in animals. These effects are the result of both inhibition of pain pathway signalling (mostly CB1) and anti-inflammatory effects (mostly CB2). There are also numerous anecdotal reports of the effectiveness of smoking cannabis for joint pain.

Indeed, it is the largest medical request for the use of the drug. However, these reports generally do not extend to regulated clinical trials for rheumatic diseases. Nevertheless, the preclinical and human data that do exist indicate that the use of cannabis should be taken seriously as a potential treatment of joint pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28967368

Do Medical Marijuana Laws Reduce Addictions and Deaths Related to Pain Killers?

NATIONAL BUREAU OF ECONOMIC RESEARCH

“Many medical marijuana patients report using marijuana to alleviate chronic pain from musculoskeletal problems and other sources. If marijuana is used as a substitute for powerful and addictive pain relievers in medical marijuana states, a potential overlooked positive impact of medical marijuana laws may be a reduction in harms associated with opioid pain relievers, a far more addictive and potentially deadly substance. To assess this issue, we study the impact of medical marijuana laws on problematic opioid use. We use two measures of problematic use: treatment admissions for opioid pain reliever addiction from the Treatment Episode Data Set (TEDS) and state-level opioid overdose deaths in the National Vital Statistics System (NVSS). Using both standard differences-in-differences models as well as synthetic control models, we find that states permitting medical marijuana dispensaries experience a relative decrease in both opioid addictions and opioid overdose deaths compared to states that do not. We find no impact of medical marijuana laws more broadly; the mitigating effect of medical marijuana laws is specific to states that permit dispensaries. We evaluate potential mechanisms. Our findings suggest that providing broader access to medical marijuana may have the potential benefit of reducing abuse of highly addictive painkillers.”

http://www.nber.org/papers/w21345.pdf

“Cannabis use is associated with a substantial reduction in premature deaths in the United States. These data suggest that Cannabis use may decrease premature deaths. Overall, prohibition is estimated to lead to similar numbers of premature deaths as drunk driving, homicide, or fatal opioid overdose. Cannabis use prevents thousands of premature deaths each year, and Cannabis prohibition is revealed as a major cause of premature death in the U.S.” https://scholarworks.iu.edu/dspace/handle/2022/21632