Category Archives: Neuropathic Pain

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

Cannabidiol-rich non-psychotropic Cannabis sativa L. oils attenuate peripheral neuropathy symptoms by regulation of CB2-mediated microglial neuroinflammation

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“Neuropathic pain (NP) is a chronic disease that affects the normal quality of life of patients. To date, the therapies available are only symptomatic and they are unable to reduce the progression of the disease. Many studies reported the efficacy of Cannabis sativa L. (C. sativa) on NP, but no Δ9 -tetrahydrocannabinol (Δ9 -THC)-free extracts have been investigated in detail for this activity so far. The principal aim of this work is to investigate the potential pain-relieving effect of innovative cannabidiol-rich non-psychotropic C. sativa oils, with a high content of terpenes (K2), compared to the same extract devoid of terpenes (K1). Oral administration of K2 (25 mg kg-1 ) induced a rapid and long-lasting relief of pain hypersensitivity in a mice model of peripheral neuropathy. In spinal cord samples, K2 reduced mitogen-activated protein kinase (MAPKs) levels and neuroinflammatory factors. These effects were reverted by the administration of a CB2 antagonist (AM630), but not by a CB1 antagonist (AM251). Conversely, K1 showed a lower efficacy in the absence of CB1/CB2-mediated mechanisms. In LPS-stimulated murine microglial cells (BV2), K2 reduced microglia pro-inflammatory phenotype through the downregulation of histone deacetylase 1 (HDAC-1) and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (IKBα) and increased interleukin-10 (IL-10) expression, an important antiinflammatory cytokine. In conclusion, these results suggested that K2 oral administration attenuated NP symptoms by reducing spinal neuroinflammation and underline the important role of the synergism between cannabinoids and terpenes.”

https://pubmed.ncbi.nlm.nih.gov/36583304/

https://onlinelibrary.wiley.com/doi/10.1002/ptr.7710

Combinations of Cannabidiol and Δ9-Tetrahydrocannabinol in Reducing Chemotherapeutic Induced Neuropathic Pain

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“Neuropathic pain is a condition that impacts a substantial portion of the population and is expected to affect a larger percentage in the future. This type of pain is poorly managed by current therapies, including opioids and NSAIDS, and novel approaches are needed. We used a cisplatin-induced model of neuropathic pain in mice to assess the effects of the cannabinoids THC and CBD alone or in varying ratios as anti-nociceptive agents. In addition to testing pure compounds, we also tested extracts containing high THC or CBD at the same ratios.

We found that pure CBD had little impact on mechanical hypersensitivity, whereas THC reduced mechanical hypersensitivity in both male and female mice (as has been reported in the literature). Interestingly, we found that high CBD cannabis extract, at the same CBD dose as pure CBD, was able to reduce mechanical hypersensitivity, although not to the same level as high THC extract. These data suggest that, at least for CBD-dominant cannabis extracts, there is an increase in the anti-nociceptive activity that may be attributed to other constitutes of the plant.

We also found that high THC extract or pure THC is the most efficacious treatment for reducing neuropathic pain in this model.”

https://pubmed.ncbi.nlm.nih.gov/36289810/

https://www.mdpi.com/2227-9059/10/10/2548/htm

Changes in the expression of endocannabinoid system components in an experimental model of chemotherapy-induced peripheral neuropathic pain: Evaluation of sex-related differences

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Experimental Neurology

“Chemotherapy-induced neuropathic pain is a serious clinical problem and one of the major side effects in cancer treatment. The endocannabinoid system (ECS) plays a crucial role in regulating pain neurotransmission, and changes in the expression of different components of the ECS have been reported in experimental models of persistent pain. In addition, sex differences have been observed in ECS regulation and function. The aim of our study was to evaluate whether administration of oxaliplatin, a neurotoxic antineoplastic agent, induced changes in the expression of ECS components in peripheral and central stations of the pain pathway, and if those changes exhibited sexual dimorphism. Adult male and female rats were injected with oxaliplatin or saline, and mechanical and cold hypersensitivity and allodynia were evaluated using Von Frey and Choi Tests. The mRNA levels corresponding to cannabinoid receptors (CB1, CB2), cannabinoid-related receptors (GPR55, 5HT1A, TRPV1) and to the main enzymes involved in the synthesis (DAGL, DAGL, NAPE-PLD) and degradation (MGL, FAAH) of endocannabinoids were assessed in lumbar dorsal root ganglia (DRGs) and spinal cord by using real time RT-PCR. In addition, the levels of the main endocannabinoids, 2-arachidonoylglycerol (2-AG) and anandamide (AEA), were evaluated using commercial ELISA kits. Oxaliplatin administration induced the development of mechanical and cold hypersensitivity and allodynia in male and female animals. Oxaliplatin also induced early and robust changes in the expression of several components of the ECS in DRGs. A marked upregulation of CB1, CB2, 5HT1A and TRPV1 was detected in both sexes. Interestingly, while DAGL mRNA levels remained unchanged, DAGL was downregulated in male and upregulated in female rats. Finally, MGL and NAPE-PLD showed increased levels only in male animals, while FAAH resulted upregulated in both sexes. In parallel, reduced 2-AG and AEA levels were detected in DRGs from male or female rats, respectively. In the lumbar spinal cord, only TRPV1 mRNA levels were found to be upregulated in both sexes. Our results reveal previously unreported changes in the expression of cannabinoid receptors, ligands and enzymes occurring mainly in the peripheral nervous system and displaying certain sexual dimorphism. These changes may contribute to the physiopathology of oxaliplatin-induced neuropathic pain in male and female rats. A better understanding of these dynamic changes will facilitate the development of mechanism- and sex-specific approaches to optimize the use of cannabinoid-based medicines for the treatment of chemotherapy-induced pain.”

https://pubmed.ncbi.nlm.nih.gov/36179876/

https://www.sciencedirect.com/science/article/abs/pii/S0014488622002576?via%3Dihub