Category Archives: Pain

Cannabis for medical use versus opioids for chronic non-cancer pain: a systematic review and network meta-analysis of randomised clinical trials

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“Objective: The objective of this study is to evaluate the comparative benefits and harms of opioids and cannabis for medical use for chronic non-cancer pain.

Design: Systematic review and network meta-analysis.

Data sources: EMBASE, MEDLINE, CINAHL, AMED, PsycINFO, PubMed, Web of Science, Cannabis-Med, Epistemonikos and the Cochrane Library (CENTRAL) from inception to March 2021.

Study selection: Randomised trials comparing any type of cannabis for medical use or opioids, against each other or placebo, with patient follow-up ≥4 weeks.

Data extraction and synthesis: Paired reviewers independently extracted data. We used Bayesian random-effects network meta-analyses to summarise the evidence and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach to evaluate the certainty of evidence and communicate our findings.

Results: Ninety trials involving 22 028 patients were eligible for review, among which the length of follow-up ranged from 28 to 180 days. Moderate certainty evidence showed that opioids provide small improvements in pain, physical functioning and sleep quality versus placebo; low to moderate certainty evidence supported similar effects for cannabis versus placebo. Neither was more effective than placebo for role, social or emotional functioning (all high to moderate certainty evidence). Moderate certainty evidence showed there is probably little to no difference between cannabis for medical use and opioids for physical functioning (weighted mean difference (WMD) 0.47 on the 100-point 36-item Short Form Survey physical component summary score, 95% credible interval (CrI) -1.97 to 2.99), and cannabis resulted in fewer discontinuations due to adverse events versus opioids (OR 0.55, 95% CrI 0.36 to 0.83). Low certainty evidence suggested little to no difference between cannabis and opioids for pain relief (WMD 0.23 cm on a 10 cm Visual Analogue Scale (VAS), 95% CrI -0.06 to 0.53) or sleep quality (WMD 0.49 mm on a 100 mm VAS, 95% CrI -4.72 to 5.59).

Conclusions: Cannabis for medical use may be similarly effective and result in fewer discontinuations than opioids for chronic non-cancer pain.”

https://pubmed.ncbi.nlm.nih.gov/38171632/

Cannabidiol and Tetrahydrocannabinol Antinociceptive Activity is Mediated by Distinct Receptors in Caenorhabditis elegans

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“Cannabis has gained popularity in recent years as a substitute treatment for pain following the risks of typical treatments uncovered by the opioid crisis. The active ingredients frequently associated with pain-relieving effects are the phytocannabinoids Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), but their effectiveness and mechanisms of action are still under research. In this study, we used Caenorhabditis elegans, an ideal model organism for the study of nociception that expresses mammal ortholog cannabinoid (NPR-19 and NPR-32) and vanilloid (OSM-9 and OCR-2) receptors. Here, we evaluated the antinociceptive activity of THC and CBD, identifying receptor targets and several metabolic pathways activated following exposure to these molecules. The thermal avoidance index was used to phenotype each tested C. elegans experimental group. The data revealed for the first time that THC and CBD decreases the nocifensive response of C. elegans to noxious heat (32-35 °C). The effect was reversed 6 h post- CBD exposure but not for THC. Further investigations using specific mutants revealed CBD and THC are targeting different systems, namely the vanilloid and cannabinoid systems, respectively. Proteomic analysis revealed differences following Reactome pathways and gene ontology biological process database enrichment analyses between CBD or THC-treated nematodes and provided insights into potential targets for future drug development.”

https://pubmed.ncbi.nlm.nih.gov/38141130/

https://link.springer.com/article/10.1007/s11064-023-04069-6

The Basic Science of Cannabinoids

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“The cannabis plant has been used for centuries to manage the symptoms of various ailments including pain.

Hundreds of chemical compounds have been identified and isolated from the plant and elicit a variety of physiological responses by binding to specific receptors and interacting with numerous other proteins.

In addition, the body makes its own cannabinoid-like compounds that are integrally involved in modulating normal and pathophysiological processes.

As the legal cannabis landscape continues to evolve within the United States and throughout the world, it is important to understand the rich science behind the effects of the plant and the implications for providers and patients.

This narrative review aims to provide an overview of the basic science of the cannabinoids by describing the discovery and function of the endocannabinoid system, pharmacology of cannabinoids, and areas for future research and therapeutic development as they relate to perioperative and chronic pain medicine.”

https://pubmed.ncbi.nlm.nih.gov/38100799/

https://journals.lww.com/anesthesia-analgesia/fulltext/2024/01000/the_basic_science_of_cannabinoids.6.aspx

Phytocannabinoids for the Treatment of Neuropathic Pain: A Scoping Review of Randomised Controlled Trials Published Between 2012 and 2023

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“Purpose of review: Neuropathic pain (NP) remains a challenge to treat, with 50% of patients experiencing limited efficacy from current treatments. Medicinal cannabis, which contains tetrahydrocannabinol (THC), cannabidiol (CBD) and other minor cannabinoids, is garnering attention as an alternative treatment for NP. This paper reviews the clinical evidence for phytocannabinoid treatment of NP.

Recent findings: Seventeen randomised controlled trials (RCT) were identified for inclusion in this review. Of these, ten studies using phytocannabinoid preparations containing THC alone had the most evidence for pain relief. Four studies investigating THC/CBD combinations showed some reductions in pain scores, although not all findings were statistically significant, whereas studies investigating CBD (two studies) or cannabidivarin (one study) showed no analgesic effect over placebo. However, CBD studies were of small sample size when compared to other studies in the review and short duration. Results for treatment of diabetic peripheral neuropathy patients with THC showed better improvements over those for NP induced by chemotherapy and multiple sclerosis, with these trials using vaporised whole plant cannabis. This formulation may have trace amounts of other minor cannabinoids, compared with synthetic cannabinoids such as dronabinol or nabilone that were investigated in other studies. This review provides an overview of RCTs that have investigated phytocannabinoid use for the treatment of NP. There appears to be evidence to necessitate further high quality RCTs into novel formulations of phytocannabinoids for the treatment of NP.”

https://pubmed.ncbi.nlm.nih.gov/38095748/

https://link.springer.com/article/10.1007/s11916-023-01196-1

Medical Cannabis: A Review from the American Society of Pain and Neuroscience

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“Cannabinoids have recently gained a renewed interest due to their potential applicability to various medical conditions, specifically the management of chronic pain conditions.

Unlike many other medications, medical cannabis is not associated with serious adverse events, and no overdose deaths have been reported.

However, both safety and efficacy data for medical cannabis treatment of chronic, nonmalignant pain conditions are lacking. Therefore, representatives from the American Society of Pain and Neuroscience summarize the evidence, according to level and grade, for medical cannabis treatment of several different pain conditions. Treatment of cancer-related pain has prospective evidentiary support for the use of medical cannabis. Although 3 large and well-designed randomized controlled trials investigated cannabis treatment of cancer-related pain, the evidence yielded only a grade D recommendation. Neuropathic pain has been investigated in prospective studies, but a lack of high-quality evidence renders cannabis treatment for this indication a grade C recommendation. Both safety and efficacy data are lacking for use of medical cannabis to treat chronic nonmalignant pain conditions.”

https://pubmed.ncbi.nlm.nih.gov/38094100/

https://www.dovepress.com/medical-cannabis-a-review-from-the-american-society-of-pain-and-neuros-peer-reviewed-fulltext-article-JPR

Relief of nocturnal neuropathic pain with the use of cannabis in a patient with Fabry disease

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“Neuropathic pain is one of the most invalidating symptoms in patients with Fabry disease (FD), affecting their quality of life, it is linked to small fiber neuropathy and it may not respond to available disease specific treatments. We report the case of a 32 years old man with classic FD and severe neuropathic pain who, after the failure of several standard pharmaceutical approaches, was treated with medical cannabis with relief of nocturnal pain and sleep improvement.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10694749/

“In conclusion: although more evidence is needed, this case report suggests that the use of medical cannabis could be considered as a pain treatment option for patient with FD, in particular for nocturnal pain relief, when other pharmacological approaches have failed.”

https://www.sciencedirect.com/science/article/pii/S2214426923000563?via%3Dihub


Antinociceptive action of cannabidiol on thermal sensitivity and post-operative pain in male and female rats

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“This study investigated the antinociceptive potential of cannabidiol (CBD) in male and female Wistar rats. The assessment and analysis included tail withdrawal to thermal stimulation (tail flick test) and mechanical allodynia induced by plantar incision injury (von Frey test). CBD reduced acute thermal sensitivity in uninjured animals and post-operative mechanical allodynia in males and females. In the tail flick test, CBD 30mg/kg i.p. was required to induce antinociception in males. During the proestrus phase, females did not show a statistically significant antinociceptive response to CBD treatment despite a noticeable trend. In contrast, in a separate group of rats tested during the late diestrus phase, antinociception varied with CBD dosage and time. In the post-operative pain model, CBD at 3mg/kg decreased mechanical allodynia in males. Similarly, this dose reduced allodynia in females during proestrus. However, in females during late diestrus, the lower dose of CBD (0.3mg/kg) reduced mechanical allodynia, although the latency to onset of the effect was slower (90minutes). The effectiveness of a 10-fold lower dose of CBD during the late diestrus stage in females suggests that ovarian hormones can influence the action of CBD. While CBD has potential for alleviating pain in humans, personalized dosing regimens may need to be developed to treat pain in women.”

https://pubmed.ncbi.nlm.nih.gov/38048909/

“•CBD produces antinociception in male and female rats.

•CBD was effective against acute thermal and post-operative pain in both sexes.

•Females in late diestrus were sensitive to a 10-fold lower dose of CBD than in proestrus.”

https://www.sciencedirect.com/science/article/pii/S0166432823005119?via%3Dihub


Terpenes in Cannabis sativa Inhibit Capsaicin Responses in Rat DRG Neurons via Na+/K+ ATPase Activation

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“Terpenes in Cannabis sativa exert analgesic effects, but the mechanisms are uncertain. We examined the effects of 10 terpenes on capsaicin responses in an established model of neuronal hypersensitivity. Adult rat DRG neurons cultured with neurotrophic factors NGF and GDNF were loaded with Fura2AM for calcium imaging, and treated with individual terpenes or vehicle for 5 min, followed by 1 µMol capsaicin. In vehicle treated control experiments, capsaicin elicited immediate and sustained calcium influx. Most neurons treated with terpenes responded to capsaicin after 6-8 min. Few neurons showed immediate capsaicin responses that were transient or normal. The delayed responses were found to be due to calcium released from the endoplasmic reticulum, as they were maintained in calcium/magnesium free media, but not after thapsigargin pre-treatment. Terpene inhibition of calcium influx was reversed after washout of medium, in the absence of terpenes, and in the presence of the Na+/K+ ATPase inhibitor ouabain, but not CB1 or CB2 receptor antagonists. Thus, terpenes inhibit capsaicin evoked calcium influx by Na+/K+ ATPase activation. Immunofluorescence showed TRPV1 co-expression with α1β1 Na+/K+ ATPase in most neurons while others were either TRPV1 or α1β1 Na+/K+ ATPase positive.”

https://pubmed.ncbi.nlm.nih.gov/38003528/

“The neuromodulatory effects of cannabinoids have been recognized for millenia in traditional medicine, including for pain relief. Following the opioid crisis, attention has been focussed on developing alternatives including cannabinoid-based pain therapies, as chronic pain remains an unmet need. The best known of the phytocannabinoids is Δ9tetrahydrocannabinol (THC), the only known psychoactive component, along with many other cannabinoids with potential therapeutic benefits, such as cannabidiol (CBD), and cannabigerol (CBG) [2]. Amongst the several hundred components in Cannabis sativa are terpenes, which are produced in small and varying amounts in different cultivars of C. sativa, leading to potential variation in their effects [3]. Some of these, including limonene, phytol, borneol, terpineol, and caryophyllene, provide pain relief via calcium channel inhibition [4]. Similarly, antinociceptive and anti-tumour effects of α-phellandrene were reported, although the mechanisms were unknown. Terpenes as a class of compounds are generally described as safe by the FDA, with low toxicity that extends their efficacy to a variety of indications including chronic pain and anxiety.”

https://www.mdpi.com/1422-0067/24/22/16340

Unlocking the Healing Potential: Cannabinoids in Spine Surgery for Pain Relief and Recovery

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“Cannabinoids, such as D9-tetrahydrocannabinol and cannabidiol, interact with endocannabinoid receptors in the central nervous system and immune system, potentially offering pain relief. The entourage effect, resulting from the interaction of multiple cannabis components, may enhance therapeutic impact and efficacy, making them promising candidates for exploring pain relief in spine operations, known to be among the most painful operative procedures.» The use of cannabinoids in pain management requires careful consideration of safety, including their cognitive and psychomotor effects, potential cardiovascular risks, risk of dependence, mental health implications, and drug interactions.» Few studies have analyzed cannabinoid use in relation to spine surgery, with variable results reported, indicating possible effects on reoperation rates, mortality, complications, postoperative opioid use, and length of hospital stay.» Current knowledge gaps exist in the understanding of cannabinoid effects on spine surgery, including the exploration of different administration routes, timing, dosage, and specific outcomes. In addition, mechanistic explanations for the observed results are lacking.» Ethical considerations related to informed consent, medical expertise, societal impact, and legal compliance must also be thoroughly addressed when considering the utilization of cannabinoids in spinal pathologies and back pain treatment.”

https://pubmed.ncbi.nlm.nih.gov/37972215/

https://journals.lww.com/jbjsreviews/abstract/2023/11000/unlocking_the_healing_potential__cannabinoids_in.4.aspx

Medical cannabis for refractory cancer-related pain in a specialised clinical service: a cross-sectional study

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“Background and objectives: Cancer-related pain management in advanced stages presents a significant challenge that often requires a multidisciplinary approach. Although advancements in pharmacological and interventional therapies, a considerable number of patients still suffer from refractory pain, leading to unmet clinical needs. This study shares our experience with medical cannabis (MC) as a potential therapy for this specific population of patients with cancer-related refractory pain.

Methods: In a cross-sectional study, 252 consecutive refractory cancer-related pain patients (mean age=61.71, SD=14.02, 47.6% males) filled out detailed self-report questionnaires. Of these, 126 patients (55%) were treated with MC and 105 patients (45%) were not.

Results: Most patients received pain management from their oncologist, not a pain specialist. MC was mainly started for pain relief, sleep difficulties and anorexia. About 70% of patients reported subjective improvement from MC, with almost 40% reporting a significant improvement in coping with their illness. Side effects were generally mild, with fatigue and dizziness being the most common (21.78% and 23.46%, respectively). No patient required dedicated medical care for side effects. Of non-users, 65% had tried MC before and stopped due to lack of effectiveness or side effects (39.7% and 34.6%, respectively).

Conclusion: Refractory cancer pain necessitates innovative approaches. This registry highlights that MC can effectively improve symptoms in non-responsive patients, with favourable safety profiles for this vulnerable population.”

https://pubmed.ncbi.nlm.nih.gov/37973200/

https://spcare.bmj.com/content/early/2023/11/15/spcare-2023-004421