Category Archives: Neuropathic Pain

Applications of Cannabinoids in Neuropathic Pain: An Updated Review

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“Neuropathic pain is experienced due to injury to the nerves, underlying disease conditions or toxicity induced by chemotherapeutics. Multiple factors can contribute to neuropathic pain such as central nervous system (CNS)-related autoimmune and metabolic disorders, nerve injury, multiple sclerosis and diabetes. Hence, development of pharmacological interventions to reduce the drawbacks of existing chemotherapeutics and counter neuropathic pain is an urgent unmet clinical need.

Cannabinoid treatment has been reported to be beneficial for several disease conditions including neuropathic pain.

Cannabinoids act by inhibiting the release of neurotransmitters from presynaptic nerve endings, modulating the excitation of postsynaptic neurons, activating descending inhibitory pain pathways, reducing neural inflammation and oxidative stress and also correcting autophagy defects. This review provides insights on the various preclinical and clinical therapeutic applications of cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN) in various diseases and the ongoing clinical trials for the treatment of chronic and acute pain with cannabinoids.

Pharmacological and genetic experimental strategies have well demonstrated the potential neuroprotective effects of cannabinoids and also elaborated their mechanism of action for the therapy of neuropathic pain.”

https://pubmed.ncbi.nlm.nih.gov/37824417/

https://www.dl.begellhouse.com/journals/3667c4ae6e8fd136,7ec6441519bff684,786cb61f3f1ec955.html

Cannabis Versus Opioids for Pain

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“In the human body, pain is an inherent alarm system that activates when there is actual or potential damage, directing an individual’s attention toward the issue. Pain is a frequently cited reason for seeking healthcare or medical assistance. Pain encompasses various elements, including nociception, the perception of pain, suffering, and pain behaviors. Although pain is a fundamental mechanism, it can become burdensome when it persists for an extended period, leading to suffering and pain-related behaviors. Chronic and unrelenting pain can cause psychological, physical, and emotional distress, adding further strain to individuals.

The search for an ideal pain relief medication has been an ongoing endeavor since ancient times, as certain types of pain still lack definitive treatment options. Several strategies have been developed to address intractable pain that does not respond to nonsteroidal anti-inflammatory drugs (NSAIDs), with opioids being the mainstay in many pain management protocols. In recent years, there has been growing and promising evidence suggesting the potential effectiveness of cannabinoids in the management of chronic pain.”

https://pubmed.ncbi.nlm.nih.gov/34424653/

Cannabis use to manage opioid cravings among people who use unregulated opioids during a drug toxicity crisis

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“Background: Accumulating evidence has indicated that cannabis substitution is often used as a harm reduction strategy among people who use unregulated opioids (PWUO) and people living with chronic pain. We sought to investigate the association between cannabis use to manage opioid cravings and self-reported changes in opioid use among structurally marginalized PWUO.

Methods: The data were collected from a cross-sectional questionnaire administered to PWUO in Vancouver, Canada. Binary logistic regression was used to analyze the association between cannabis use to manage opioid cravings and self-reported changes in unregulated opioid use.

Results: A total of 205 people who use cannabis and opioids were enrolled in the present study from December 2019 to November 2021. Cannabis use to manage opioid cravings was reported by 118 (57.6%) participants. In the multivariable analysis, cannabis use to manage opioid cravings (adjusted Odds Ratio [aOR] = 2.13, 95% confidence interval [CI]: 1.07, 4.27) was significantly associated with self-reported reductions in opioid use. In the sub-analyses of pain, cannabis use to manage opioid cravings was only associated with self-assessed reductions in opioid use among people living with moderate to severe pain (aOR = 4.44, 95% CI: 1.52, 12.97). In the sub-analyses of males and females, cannabis use to manage opioid cravings was only associated with self-assessed reductions in opioid use among females (aOR = 8.19, 95% CI: 1.20, 55.81).

Conclusions: These findings indicate that cannabis use to manage opioid cravings is a prevalent motivation for cannabis use among PWUO and is associated with self-assessed reductions in opioid use during periods of cannabis use. Increasing the accessibility of cannabis products for therapeutic use may be a useful supplementary strategy to mitigate exposure to unregulated opioids and associated harm during the ongoing drug toxicity crisis.”

https://pubmed.ncbi.nlm.nih.gov/37481875/

https://www.sciencedirect.com/science/article/abs/pii/S0955395923001603?via%3Dihub

Offering an Alternative to Persons with Chronic Pain: How Access to Cannabis May Provide an Off-Ramp from Undesired Prescription Opioid Use

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“Background: Chronic pain (CP) is experienced by as many as 50 million Americans and can negatively impact physical and mental health. Prescribing opioids is the most common approach to address moderate to severe CP though these potent analgesics are associated with a significant number of side effects. One alternative some Americans are turning to for CP management is cannabis. In addition to serving as an alternative, many individuals with CP use cannabis in addition to using prescription opioids. This study examined individuals with CP who enrolled in the state of Illinois’ opioid diversion program, the Opioid Alternative Pilot Program (OAPP), which offers individuals aged 21 and older a separate pathway to access medical cannabis if they have or could receive a prescription for opioids as certified by a licensed physician.

Methods: Cross-sectional survey data were collected from 450 participants. We described participants and compared those who use only cannabis with those who use cannabis and opioids.

Results: While 16% of the respondents were cannabis-only users, 84% of the respondents were co-users of opioids and cannabis. Both groups considered opioid use risky (100% cannabis-only, 89% co-users,). The majority (73%) of respondents sought to completely stop or never start using opioids for CP. Cannabis-only users reported lower levels of pain compared to co-users. Co-users (85%) were more likely to have their routine provider as a cannabis certifying physician than cannabis-only users (69%).

Conclusion: With increasing clinical evidence, legalization and acceptance, researchers should continue to examine how cannabis may be a viable alternative to reduce the risk of prescription opioid side effects, misuse, or dependence. Our findings also inform health care providers and state policymakers who increasingly are being asked to consider how cannabis may reduce the potential for harmful outcomes among persons with CP who use prescription opioids.”

https://pubmed.ncbi.nlm.nih.gov/37484046/

https://publications.sciences.ucf.edu/cannabis/index.php/Cannabis/article/view/125

Perceived Effectiveness of Medical Cannabis Among Adults with Chronic Pain: Findings from Interview Data in a Three-Month Pilot Study

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“Objectives: Patient-reported outcomes are critical to evaluate the effectiveness of medical cannabis as an alternative treatment for chronic pain. This study examined the perceived effectiveness of medical cannabis for chronic pain management among middle-aged and older adults newly initiating medical cannabis.

Methods: Interview data from participants in a three-month pilot study were analyzed to assess the perceived effectiveness of medical cannabis on chronic pain and related outcomes. The interview was conducted after approximately one month of usage and responses were analyzed using the RADaR (Rigorous and Accelerated Data Reduction) technique.

Results: 51 adults initiating medical cannabis for chronic pain were interviewed (24 women, 27 men, mean age 54.4, SD = 12.0), with the majority (n=41) identifying as Non-Hispanic White followed by Non-Hispanic Black (n=7), Multi-racial (2), Hispanic White (1). Most study participants (62.7%) reported MC being overall effective. Common benefits included reduced pain intensity, anxiety, and dependency on pain and psychiatric medications. Improvements in physical functioning, sleep quality, and mood were reported. Common challenges included difficulty finding a suitable product or dose, experiencing side effects such as ‘undesired high’, ‘stomach issues’, and a limited ‘threshold of pain’ treatable by the product.

Discussion: Findings suggest most participants perceived medical cannabis to be overall effective for chronic pain management. Participants reported improved physical and mental functioning and reduced use of pain and psychiatric medications. Future research systematically assessing side effects, dosage and mode of consumption is needed to further evaluate the outcomes among adults initiating medical cannabis.”

https://pubmed.ncbi.nlm.nih.gov/37484052/

https://publications.sciences.ucf.edu/cannabis/index.php/Cannabis/article/view/149

Anti-allodynic and medullary modulatory effects of a single dose of delta-9-tetrahydrocannabinol (THC) in neuropathic rats tolerant to morphine

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“Neuropathic pain (NP) is often treated with opioids, the prolonged use of which causes tolerance to their analgesic effect and can potentially cause death by overdose. The phytocannabinoid delta-9-tetrahydrocannabinol (THC) may be an effective alternative analgesic to treat NP in morphine-tolerant subjects. Male Wistar rats developed NP after spared nerve injury, and were then treated with increasing doses of THC (1, 1.5, 2, 2.5, and 5 mg/kg, intraperitoneally) which reduced mechanical allodynia at the dose of 2.5 and 5 mg/kg. Another group of NP rats were treated with morphine (5 mg/kg, twice daily for 7 days, subcutaneously), until tolerance developed, and on day 8 received a single dose of THC (2.5 mg/kg), which significantly reduced mechanical allodynia. To evaluate the modulation of THC in the descending pain pathway, in vivo electrophysiological recordings of pronociceptive ON cells and antinociceptive OFF cells in the rostroventral medulla (RVM) were recorded after intra-PAG microinjection of THC (10 μg/μl). NP rats with morphine tolerance, compared to the control one, showed a tonic reduction of the spontaneous firing rate of ON cells by 44%, but the THC was able to further decrease it (a hallmark of many analgesic drugs acting at supraspinal level). On the other hand, the firing rate, of the antinociceptive OFF cells was increased after morphine tolerance by 133%, but the THC failed to further activate it. Altogether, these findings indicate that a single dose of THC produces antiallodynic effect in individuals with NP who are tolerant to morphine, acting mostly on the ON cells of the descending pain pathways, but not on OFF cells.”

https://pubmed.ncbi.nlm.nih.gov/37257771/

https://www.sciencedirect.com/science/article/abs/pii/S027858462300091X?via%3Dihub

Cannabidiol alleviates neuroinflammation and attenuates neuropathic pain via targeting FKBP5

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Brain, Behavior, and Immunity

“Microglia is a heterogeneous population that mediates neuroinflammation in the central nervous system (CNS) and plays a crucial role in developing neuropathic pain. FKBP5 facilitates the assembly of the IκB kinase (IKK) complex for the activation of NF-κB, which arises as a novel target for treating neuropathic pain. In this study, cannabidiol (CBD), a main active component of Cannabis, was identified as an antagonist of FKBP5. In vitro protein intrinsic fluorescence titration showed that CBD directly bound to FKBP5. Cellular thermal shift assay (CETSA) indicated that CBD binding increased the FKBP5 stability, which implies that FKBP5 is the endogenous target of CBD. CBD was found to inhibit the assembly of the IKK complex and the activation of NF-κB, therefore blocking LPS-induced NF-κB downstream pro-inflammatory factors NO, IL-1β, IL-6 and TNF-α. Stern-Volmer analysis and protein thermal shift assay revealed that tyrosine 113 (Y113) of FKBP5 was critical for FKBP5 interacting with CBD, which is consistent with in silico molecular docking simulation. FKBP5 Y113 mutation (Y113A) alleviated the effect of CBD inhibiting LPS-induced pro-inflammatory factors overproduction. Furthermore, systemic administration of CBD inhibited chronic constriction injury (CCI)-induced microglia activation and FKBP5 overexpression in lumbar spinal cord dorsal horn. These data imply that FKBP5 is an endogenous target of CBD.”

https://pubmed.ncbi.nlm.nih.gov/37196785/

“Cannabidiol (CBD) is the main active component of cannabis with good BBB permeability (Calapai et al., 2020) and has been gaining great attention for its safety, non-psychoactive effect and several beneficial pharmacological activities (Devinsky et al., 2016, Lucas et al., 2018, Pisanti et al., 2017). CBD has a good anti-neuroinflammatory effect (Atalay et al., 2019) and is used to treat neurological diseases caused by neuroinflammation, such as major depression (Florensa-Zanuy et al., 2021) and Parkinson’s disease (Giuliano et al., 2021) in animal models as well as autism spectrum disorder (Carbone et al., 2021) and multiple sclerosis (Nielsen et al., 2018) in clinical trials. As CBD has a low affinity for cannabinoid receptors (Rosenthaler et al., 2014), it would be worthy to explore the molecular target, which mediates the anti-inflammatory activity of CBD. Herein, FKBP5 was found as an endogenous target of CBD. CBD inhibited the assembly of the IKK complex and the activation of NF-κB, therefore suppressing LPS-induced pro-inflammatory factors. The FKBP5 tyrosine 113 (Y113) mutation abolished FKBP5 interacting with CBD, therefore ameliorating the effect of CBD inhibiting LPS-induced pro-inflammatory factors. Moreover, oral CBD attenuated peripheral nerve injury-induced overexpression of FKBP5 in activated microglia of lumbar spinal cord dorsal horn in vivo. These data implicate that FKBP5 is a direct binding target of CBD.”

https://www.sciencedirect.com/science/article/abs/pii/S0889159123001265?via%3Dihub

Cannabidiol prevents chemotherapy-induced neuropathic pain by modulating spinal TLR4 via endocannabinoid system activation

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Journal of Pharmacy and Pharmacology

“Objectives: This study aimed to investigate the effect of cannabidiol (CBD) on type 4 Toll-like receptors (TLR4), glial cells and pro-inflammatory cytokines during the neuropathic pain induced by the chemotherapy agent paclitaxel (PTX), as well as the involvement of the endocannabinoid system in this process.

Methods: Male C57BL6 mice were subjected to PTX-induced neuropathic pain. To evaluate the involvement of the TLR4, glial cells and cannabinoid CB2 receptor, specific inhibitors or antagonists were intrathecally administered. The western blotting and immunofluorescence assay was performed to evaluate the spinal expression of TLR4, microglia, astrocytes and cannabinoid CB2 receptor. The levels of spinal pro-inflammatory cytokines and endocannabinoids were determined by enzyme-linked immunosorbent assay and liquid chromatography-mass spectrometry analysis, respectively.

Key findings: CBD prevented PTX-induced neuropathic pain, and the cannabinoid CB2 receptor antagonist AM630 reversed this effect. In addition, CBD treatment inhibited the spinal expression of TLR4 and Iba1 in mice with neuropathic pain. CBD also increased spinal levels of endocannabinoids anandamide and 2-arachidonoylglycerol, and reduced levels of cytokines in mice with neuropathic pain.

Conclusions: CBD was efficient in preventing PTX-induced neuropathic pain, and this effect may involve inhibition of the TLR4 on microglia spinal with activation of the endocannabinoid system.”

https://pubmed.ncbi.nlm.nih.gov/36946366/

https://academic.oup.com/jpp/advance-article-abstract/doi/10.1093/jpp/rgad023/7083482?redirectedFrom=fulltext&login=false

A Retrospective Medical Record Review of Adults with Non-Cancer Diagnoses Prescribed Medicinal Cannabis

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“Research describing patients using medicinal cannabis and its effectiveness is lacking. We aimed to describe adults with non-cancer diagnoses who are prescribed medicinal cannabis via a retrospective medical record review and assess its effectiveness and safety. From 157 Australian records, most were female (63.7%; mean age 63.0 years). Most patients had neurological (58.0%) or musculoskeletal (24.8%) conditions. Medicinal cannabis was perceived beneficial by 53.5% of patients.

Mixed-effects modelling and post hoc multiple comparisons analysis showed significant changes overtime for pain, bowel problems, fatigue, difficulty sleeping, mood, quality of life (all p < 0.0001), breathing problems (p = 0.0035), and appetite (p = 0.0465) Symptom Assessment Scale scores. For the conditions, neuropathic pain/peripheral neuropathy had the highest rate of perceived benefit (66.6%), followed by Parkinson’s disease (60.9%), multiple sclerosis (60.0%), migraine (43.8%), chronic pain syndrome (42.1%), and spondylosis (40.0%). For the indications, medicinal cannabis had the greatest perceived effect on sleep (80.0%), followed by pain (51.5%), and muscle spasm (50%). Oral oil preparations of balanced delta-9-tetrahydrocannabinol/cannabidiol (average post-titration dose of 16.9 mg and 34.8 mg per day, respectively) were mainly prescribed. Somnolence was the most frequently reported side effect (21%).

This study supports medicinal cannabis’ potential to safely treat non-cancer chronic conditions and indications.”

“Cannabis (Cannabaceae) has been used medicinally since 400 AD for its analgesic, appetite enhancement, and myorelaxant properties. Emerging evidence suggests that people with chronic conditions may benefit from using medicinal cannabis for treating chronic pain, multiple sclerosis-related spasticity, epilepsy, Parkinson’s disease, insomnia, and anxiety.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9965412/

Evaluating the impact of cannabinoids on sleep health and pain in patients with chronic neuropathic pain: a systematic review and meta-analysis of randomized controlled trials

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“Background: Chronic neuropathic pain is often debilitating and can have a significant impact on sleep health and quality of life. There is limited information on the impact of cannabinoids on sleep health when treating neuropathic pain.

Objective: The objectives of this systematic review and meta-analysis were to determine the effect of cannabinoids on sleep quality, pain intensity, and patient impression of treatment efficacy in patients with neuropathic pain.

Evidence review: Nine available medical literature databases were searched for randomized controlled trials comparing synthetic and natural cannabinoids to placebo in patients with neuropathic pain syndromes. Data on validated tools for sleep quality, pain intensity, patients’ global impression of change (PGIC), and incidence of adverse effects of cannabinoids were extracted and synthesized.

Findings: Of the 3491 studies screened, eight randomized controlled trials satisfied the inclusion criteria for this review. Analyses were performed using R -4.1.2. using the metafor package and are interpreted using alpha=0.05 as the threshold for statistical significance. Validated measures for sleep health were not used in most studies. Meta-analysis of data from six studies showed that cannabinoids were associated with a significant improvement in sleep quality (standardized mean difference (SMD): 0.40; 95% CI: 0.19 to -0.61, 95% prediction interval (PI): -0.12 to 0.88, p-value=0.002, I2=55.26, τ2=0.05, Q-statistic=16.72, GRADE: moderate certainty). Meta-analysis of data from eight studies showed a significant reduction in daily pain scores in the cannabinoid (CB) group (SMD: -0.55, 95% CI:-0.69 to -0.19, 95% PI: -1.51 to 0.39, p=0.003, I2=82.49, τ2=0.20, Q-statistic=47.69, GRADE: moderate certainty). However, sleep health and analgesic benefits were associated with a higher likelihood of experiencing daytime somnolence, nausea, and dizziness.

Conclusions: Cannabinoids have a role in treating chronic neuropathic pain as evidenced by significant improvements in sleep quality, pain intensity, and PGIC. More research is needed to comprehensively evaluate the impact of cannabinoids on sleep health and analgesic efficacy.”

https://pubmed.ncbi.nlm.nih.gov/36598058/

https://rapm.bmj.com/content/early/2022/12/04/rapm-2021-103431