Category Archives: Pain

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

Effectiveness of Cannabidiol to Manage Chronic Pain: A Systematic Review

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“Objectives: Cannabidiol (CBD), a component in Cannabis, is used to treat seizures, anxiety, and pain. Little is known about how effectively CBD works in managing chronic pain, a condition characterized by discomfort that persists beyond 3-6 months or beyond expected normal healing. Therefore, this systematic review aimed to synthesize evidence on the effectiveness of CBD in chronic pain management.

Design: A systematic review of literature utilizing PRISMA 2020 guidelines.

Data sources: PubMed/MEDLINE, Web of Science, CINAHL, Academic Search Complete, PsycArticles, PsycINFO, SocINDEX, and CENTRAL. The gray literature search was performed through the World Health Organization, the Centers for Disease Control and Prevention, and the European Centre for Disease Prevention and Control.

Review/analysis methods: We searched eight databases and gray literature for relevant studies until August 30, 2022. We gathered original research articles with various study designs published in English that looked at patients who used CBD to manage their chronic pain. Two authors assessed the risk of bias and certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used narrative synthesis to analyze the results.

Results: We included 15 studies among 1,516 identified articles. The majority of the studies indicated pain reduction ranging from 42% – 66% with CBD alone and CBD with Tetrahydrocannabinol. Three studies showed no significant improvement in reducing pain, and one had mixed findings in pain control. The included studies had various methods of measuring pain reduction, mostly through self-reporting and scales such as visual analog scales and verbal numerical scales, among others.

Conclusion: CBD may be useful in treating chronic pain. Findings should be interpreted with caution due to the small number of included studies and heterogeneity brought about by different study designs and outcome measures. More studies with robust study designs are warranted to evaluate CBD’s effectiveness in treating chronic pain.”

https://pubmed.ncbi.nlm.nih.gov/37953193/

https://www.painmanagementnursing.org/article/S1524-9042(23)00193-5/fulltext

The holistic effects of medical cannabis compared to opioids on pain experience in Finnish patients with chronic pain

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“Background: Medical cannabis (MC) is increasingly used for chronic pain, but it is unclear how it aids in pain management. Previous literature suggests that MC could holistically alter the pain experience instead of only targeting pain intensity. However, this hypothesis has not been previously systematically tested.

Method: A retrospective internet survey was used in a sample of Finnish chronic pain patients (40 MC users and 161 opioid users). The patients evaluated statements describing positive and negative phenomenological effects of the medicine. The two groups were propensity score matched to control for possible confounding factors.

Results: Exploratory factor analysis revealed three experience factors: Negative Side Effects, Positive Holistic Effects, and Positive Emotional Effects. The MC group (matched n = 39) received higher scores than the opioid group (matched n = 39) in Positive Emotional Effects with large effect size (Rank-Biserial Correlation RBC = .71, p < .001), and in Holistic Positive Effects with medium effect size (RBC = .47, p < .001), with no difference in Negative Side Effects (p = .13). MC and opioids were perceived as equally efficacious in reducing pain intensity. Ratings of individual statements were exploratively examined in a post hoc analysis.

Conclusion: MC and opioids were perceived to be equally efficacious in reducing pain intensity, but MC additionally positively affected broader pain-related factors such as emotion, functionality, and overall sense of wellbeing. This supports the hypothesis that MC alleviates pain through holistically altering the pain experience.”

https://pubmed.ncbi.nlm.nih.gov/37941019/

“The results of the present study support the hypothesis that the effects of MC on pain experience are more holistic than those of opioids. MC may alleviate pain through affecting a broad range of pain-related experience experiental factors such as relaxation, improved sleep and mood, being able not to react to the pain, as well as a sense of control. These holistic effects of MC could explain the inconsistencies in clinical trials, where focus has mainly been on pain intensity instead of broader pain phenomenology. The results highlight the importance of taking these holistic effects into account in treating patients with MC, considering them as part of the therapeutic process.”

https://jcannabisresearch.biomedcentral.com/articles/10.1186/s42238-023-00207-7

Dysregulation of the endogenous cannabinoid system following opioid exposure

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“Rates of opioid-related deaths and overdoses in the United States are at record-high levels. Thus, novel neurobiological targets for the treatment of OUD are greatly needed. Given the close interaction between the endogenous opioid system and the endocannabinoid system (ECS), targeting the ECS may have therapeutic potential in OUD.

The various components of the ECS, including cannabinoid receptors, their lipid-derived endogenous ligands (endocannabinoids [eCBs]), and the related enzymes, present potential targets for developing new medications in OUD treatment.

The purpose of this paper is to review the clinical and preclinical literature on the dysregulation of the ECS after exposure to opioids. We review the evidence of ECS dysregulation across various study types, exposure protocols, and measurement protocols and summarize the evidence for dysregulation of ECS components at specific brain regions.

Preclinical research has shown that opioids disrupt various ECS components that are region-specific. However, the results in the literature are highly heterogenous and sometimes contradictory, possibly due to variety of different methods used. Further research is needed before a confident conclusion could be made on how exposure to opioids can affect ECS components in various brain regions.”

https://pubmed.ncbi.nlm.nih.gov/37931479/

https://www.sciencedirect.com/science/article/abs/pii/S016517812300536X?via%3Dihub