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

Preferences for Medical Marijuana over Prescription Medications Among Persons Living with Chronic Conditions: Alternative, Complementary, and Tapering Uses.

Mary Ann Liebert, Inc. publishers

“Despite expanded legalization and utilization of medical cannabis (MC) internationally, there is a lack of patient-centered data on how MC is used by persons living with chronic conditions in tandem with or instead of prescription medications. This study describes approaches to use of MC vis-à-vis prescription medications in the treatment of selected chronic conditions.

RESULTS:

Participants described a range of approaches to using MC, including (1) as alternatives to using prescription or over-the-counter medications; (2) complementary use with prescription medications; and (3) as a means for tapering off prescription medications. Motives reported for reducing or eliminating prescription medications included concerns regarding toxicity, dependence, and tolerance, and perceptions that MC improves management of certain symptoms and has quicker action and longer lasting effects.

CONCLUSIONS:

MC appears to serve as both a complementary method for symptom management and treatment of medication side-effects associated with certain chronic conditions, and as an alternative method for treatment of pain, seizures, and inflammation in this population. Additional patient-centered research is needed to identify specific dosing patterns of MC products associated with symptom alleviation and produce longitudinal data assessing chronic disease outcomes with MC use.”

Efficacy of Cannabis-Based Medicines for Pain Management: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

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“The management of chronic pain is a complex challenge worldwide. Cannabis-based medicines (CBMs) have proven to be efficient in reducing chronic pain, although the topic remains highly controversial in this field.

OBJECTIVES:

This study’s aim is to conduct a conclusive review and meta-analysis, which incorporates all randomized controlled trials (RCTs) in order to update clinicians’ and researchers’ knowledge regarding the efficacy and adverse events (AEs) of CBMs for chronic and postoperative pain treatment.

CONCLUSIONS:

The current systematic review suggests that CBMs might be effective for chronic pain treatment, based on limited evidence, primarily for neuropathic pain (NP) patients. Additionally, GI AEs occurred more frequently when CBMs were administered via oral/oromucosal routes than by inhalation.”

https://www.ncbi.nlm.nih.gov/pubmed/28934780

Results of a Double-Blind, Randomized, Placebo-Controlled Study of Nabiximols Oromucosal Spray as Adjunctive Therapy in Advanced Cancer Patients With Chronic Uncontrolled Pain.

Journal of Pain and Symptom Management Home

“Prior phase 2/3 studies found that cannabinoids might provide adjunctive analgesia in advanced cancer patients with uncontrolled pain.

To assess adjunctive nabiximols (Sativex®), an extract of Cannabis sativa containing two potentially therapeutic cannabinoids (Δ9-tetrahydrocannabinol and cannabidiol, in advanced cancer patients with chronic pain unalleviated by optimized opioid therapy.

Nabiximols was statistically superior to placebo on two of three quality-of-life instruments at week 3 and on all three at week 5.

The safety profile of nabiximols was consistent with earlier studies.

Although not superior to placebo on the primary efficacy endpoint, nabiximols had benefits on multiple secondary endpoints, particularly in US patients.

Nabiximols might have utility in patients with advanced cancer who receive a lower opioid dose, such as individuals with early intolerance to opioid therapy.”

https://www.ncbi.nlm.nih.gov/pubmed/28923526

http://www.jpsmjournal.com/article/S0885-3924(17)30465-7/fulltext

Activation of dorsal horn cannabinoid CB2 receptor suppresses the expression of P2Y12 and P2Y13 receptors in neuropathic pain rats.

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“More evidence suggests that dorsal spinal cord microglia is an important site contributing to CB2 receptor-mediated analgesia. The upregulation of P2Y12 and P2Y13 purinoceptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not known whether the expression of P2Y12 and P2Y13 receptors at spinal dorsal horn will be influenced after CB2 receptor activation in neuropathic pain rats. Chronic constriction injury (CCI) and intrathecal ADPbetaS injection were performed in rats to induce neuropathic pain.

In CCI- and ADPbetaS-treated rats, AM1241 pretreatment could efficiently activate CB2 receptor, while inhibiting p38MAPK and NF-kappaB activation in the dorsal spinal cord. CB2 receptor stimulation decreased P2Y13 receptor expression via p38MAPK/NF-kappaB signaling. On the other hand, CB2 receptor activation decreased P2Y12 receptor expression via p38MAPK-independent NF-kappaB signaling pathway.”

https://www.ncbi.nlm.nih.gov/pubmed/28899427

Attenuation of early phase inflammation by cannabidiol prevents pain and nerve damage in rat osteoarthritis.

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“Osteoarthritis (OA) is a multifactorial joint disease, which includes joint degeneration, intermittent inflammation, and peripheral neuropathy. Cannabidiol (CBD) is a non-euphoria producing constituent of cannabis that has the potential to relieve pain.

The aim of this study was to determine if CBD is anti-nociceptive in OA, and whether inhibition of inflammation by CBD could prevent the development of OA pain and joint neuropathy.

The therapeutic and prophylactic effects of peripheral CBD (100-300μg) were assessed. In end stage OA, CBD dose-dependently decreased joint afferent firing rate, and increased withdrawal threshold and weight bearing (p<0.0001; n=8). Acute, transient joint inflammation was reduced by local CBD treatment (p<0.0001; n=6). Prophylactic administration of CBD prevented the development of MIA-induced joint pain at later time points (p<0.0001; n=8), and was also found to be neuroprotective (p<0.05; n=6-8).

The data presented here indicate that local administration of CBD blocked OA pain. Prophylactic CBD treatment prevented the later development of pain and nerve damage in these OA joints.

These findings suggest that CBD may be a safe, useful therapeutic for treating OA joint neuropathic pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28885454             https://insights.ovid.com/crossref?an=00006396-900000000-99152

Cannabis constituent synergy in a mouse neuropathic pain model.

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“Cannabis and its psychoactive constituent Δ9-tetrahydrocannabinol (THC) have efficacy against neuropathic pain however, this is hampered by their side-effects. It has been suggested that co-administration with another major constituent cannabidiol (CBD) might enhance the analgesic actions of THC and minimise its deleterious side-effects.

We examined the basis for this phytocannabinoid interaction in a mouse chronic constriction injury (CCI) model of neuropathic pain. Acute systemic administration of THC dose-dependently reduced CCI-induced mechanical and cold allodynia, but also produced motor incoordination, catalepsy and sedation. CBD produced a lesser dose-dependent reduction in allodynia, but did not produce the cannabinoid side-effects. When co-administered in a fixed ratio, THC and CBD produced a biphasic dose-dependent reduction in allodynia. At low doses, the THC:CBD combination displayed a 200-fold increase in anti-allodynic potency, but had lower efficacy compared to that predicted for an additive drug interaction. By contrast, high THC:CBD doses had lower potency, but greater anti-allodynic efficacy compared to that predicted for an additive interaction. Only the high dose THC:CBD anti-allodynia was associated with cannabinoid side-effects and these were similar to those of THC alone. Unlike THC, the low dose THC:CBD anti-allodynia was not cannabinoid receptor mediated.

These findings demonstrate that CBD synergistically enhances the pain relieving actions of THC in an animal neuropathic pain model, but has little impact on the THC-induced side-effects. This suggests that low dose THC:CBD combination treatment has potential in the treatment of neuropathic pain.”