Cannabis-based medicines for chronic neuropathic pain in adults

Burns and Mental Health: A Matched Cohort Study

OBJECTIVE

To determine the association between burns and hospitalization for mental health disorders up to 3 decades later.

BACKGROUND

Burns are associated with pain, disability, and scarring, but the long-term impact on mental health is unclear.

METHODS

We analyzed a cohort of 23,726 patients with burns aged ≥10 years who were matched to 223,626 controls from Quebec, Canada, between 1989 and 2022. The main exposure was admission for a burn. We followed patients during 3,642,206 person-years of follow-up to identify future hospitalizations for psychiatric disorders, substance use disorders, and suicide attempts. We estimated adjusted hazard ratios (HRs) with 95% CIs for the association between burns and subsequent mental health hospitalization using Cox proportional hazards regression.

RESULTS

Patients with burns had a 1.76 times greater risk of mental health hospitalization over time (95% CI: 1.72-1.81), compared with controls. Associations were present regardless of burn site, but were greatest for burns covering ≥50% of the body (HR: 3.29, 95% CI: 2.61-4.15), third-degree burns (HR: 2.04, 95% CI: 1.94-2.14), and burns requiring skin grafts (HR: 2.00, 95% CI: 1.90-2.10). Compared with controls, patients with burns had more than two times the risk of hospitalization for eating disorders (HR: 3.14, 95% CI: 2.50-3.95), psychoactive substance use disorders (HR: 2.27, 95% CI: 2.17-2.39), and suicide attempts (HR: 2.42, 95% CI: 2.23-2.62). Risks were particularly elevated within 5 years of the burn but persisted throughout follow-up.

CONCLUSIONS

Burns are associated with an increased risk of hospitalization for mental health disorders up to 30 years later.

Mechanistic study of modulating mitochondrial fission and fusion to ameliorate neuropathic pain in mice

The emergence of neuropathic pain is significantly influenced by the impairment of mitochondrial processes. Ensuring the stability of mitochondrial activity requires a delicate equilibrium between the processes of mitochondrial fission and fusion. However, the specific alterations in mitochondrial activity across different models of neuropathic pain and the underlying mechanisms remain largely unclear. We developed a persistent compression injury (CCI) model targeting the sciatic nerve in mice. CCI induced pain like behaviors in mice, which were associated with increased levels of dynamin related protein 1 (Drp1) and decreased expression of the fusion protein OPA1 and an increase in the percentage of DRG nerve cell mitochondria in the fission form, and a decrease in percentage in the fusion form. Ultrastructural analysis showed that mitochondria in CCI mice were smaller in perimeter and area, adopting a more circular shape. Overexpression of OPA1 mediated by AAV attenuated pain hypersensitivity, lowered oxidative stress, and expanded mitochondrial circumference and area. Mdivi-1 treatment reduced pain, whereas blocking fusion with MYLS22 augmented pain and oxidative stress and further led to increased mitochondrial fragmentation. Our results illustrate that Mitochondria in DRG nerve cell are highly sensitive to neuropathic pain. Modulating mitochondrial fission and fusion through targeted gene overexpression and pharmacological inhibitors restores mitochondrial dynamics, reduces oxidative stress, and alleviates neuropathic pain in mice. These findings position mitochondrial dynamics as promising therapeutic targets for pain management.

Patterns, Efficacy, and Cognitive Effects of Medical Cannabis Use in Chronic Musculoskeletal Pain Patients

BACKGROUND

Medical cannabis (MC) is being used with greater frequency in the management of chronic pain. While its efficacy in pain relief is promising, questions about patterns of use and efficacy warrant further investigation. This study aimed to evaluate long-term MC use patterns, perceived efficacy, and its impact on cognition among patients with chronic musculoskeletal noncancer pain.

METHODS

This prospective study included patients who were certified for MC between October 2022 and December 2024. Patients who were certified for MC under Pennsylvania state guidelines for a minimum of one year were tracked, yielding 129 patients for analysis. The patients completed an Inventory of Medical Cannabis Use (IMCU) questionnaire assessing usage patterns, dosage knowledge, efficacy, cognitive effects, and tolerance changes. The responses were collected in a password-protected database.

RESULTS

A total of 77.5% of patients reported using MC daily or near daily. Topical formulations were most frequently used (63.6%). Approximately half of the respondents were uncertain of their exact tetrahydrocannabinol/cannabidiol (THC/CBD) dosage, with a median oral dose of 10 mg recorded among those who provided estimates. High levels of perceived efficacy were reported, with over 93% of respondents agreeing or strongly agreeing that MC improved their primary symptoms. Cognitive and motor effects were minimal for most users, with 72.1% reporting no impact. Furthermore, 79.8% of respondents indicated stable usage patterns over the prior three months, and very few reported a need or external suggestion to reduce MC intake.

CONCLUSIONS

Long-term MC use is a stable and well-tolerated option for managing chronic musculoskeletal pain, with high patient-reported efficacy and minimal cognitive impact. These findings support its role in pain management while highlighting the need for further research on optimal dosing and long-term safety.

Considering Long-Acting Synthetic Cannabidiol for Chronic Pain: A Narrative Review

Chronic pain is prevalent and challenging to treat. Cannabinoids, in particular cannabidiol (CBD), have been evaluated as analgesics without the issues of tolerance or dependence. Side effects tend to be mild and infrequent. These products have multiple routes of administration and composition, and some are available over the counter, allowing pain patients to self-medicate. Most self-medicated CBD are plant-derived extracts administered as either oils, pills, or by inhalation. During the early 1960s, CBD was chemically synthesized for the first time, but it was not yet approved for medical use; synthetic CBD has been and continues to be studied in clinical trials for numerous indications, including chronic pain, neuropathic pain, and pain in cancer. However, studies are often small, populations heterogeneous, and some results are equivocal. Research is lively, with over 60 studies reported on ClinicalTrials.gov. Multimodal CBD therapy may hold promise, particularly in combination with palmitoylethanolamide. Greater patient education and training for physicians and other healthcare providers are needed along with more comprehensive studies. Considering the problem of chronic pain, further intensive study of synthetic CBD for pain control is warranted to meet this unmet clinical need. This is particularly important in the context of long-lasting administration methods that enable easy dosing and support long-term use for patients dealing with persistent and often debilitating symptoms.

Association Between Legal Access to Medical Cannabis and Frequency of Non-Medical Prescription Opioid Use Among U.S. Adults

The impact of state-level medical cannabis laws (MCL) on individual-level opioid outcomes is inconclusive. We analyzed representative samples of U.S. adults ≥21 years reporting past-year non-medical prescription opioid (NMPO) use in the 2004-2014 National Surveys on Drug Use and Health. Multi-level mixed effects models estimated associations of state-level MCL with individual-level NMPO use frequency, categorized as occasional (1-12 days), regular (13-52 days), or frequent (53-365 days). Further analyses stratified by past-year cannabis use and disorder (no use, use only, DSM-IV cannabis use disorder). MCL was associated with increases in occasional use (2.1 percentage points, 95% CI: 0.5, 3.8) alongside reductions in regular (-0.6 percentage points, 95% CI: -1.1, -0.1) and frequent use (-1.5 percentage points, 95% CI: -2.7, -0.4). In stratified analyses, significant changes were observed only for adults with cannabis use disorder, including increases in occasional use (5.6 percentage points, 95% CI: 1.5, 9.6) and decreases in frequent use (-4.9 percentage points, 95% CI: -8.1, -1.8). The association of MCL with lower frequency of NMPO use was driven by individuals with cannabis use disorder, highlighting the importance of identifying tradeoffs of cannabis legalization as an intervention to reduce opioid-related harms.

Pharmacokinetics and Side Effects of Δ9-Tetrahydrocannabinol and Cannabidiol in Patients with Different Stages of CKD

Introduction

Chronic kidney disease (CKD) affects approximately 10% of the global population and is associated with a large symptom burden. Medicinal cannabis is advised against in patients with severe CKD. However, pharmacokinetic and pharmacodynamic knowledge regarding their use in patients with CKD is lacking.

Methods

We aimed to investigate the pharmacokinetics and side effects of a single dose of Sativex, corresponding to 5.4 mg Δ9-tetrahydrocannabinol (THC) and 5 mg cannabidiol (CBD), in patients with CKD stages 4 and 5 compared with healthy volunteers (controls). The study was a nonrandomized and unblinded clinical study.

Results

Twenty controls and 29 patients with CKD completed the study. The area under the curve (AUC) for THC (median [interquartile range]) was 2.76 (1.77-3.48), 4.16 (3.35-5.28), and 4.31 (3.16-5.42) h × ng/ml for controls, and for patients with CKD stages 4 and 5, respectively, with significant differences between patients with CKD and controls. AUC for CBD and metabolites, and other pharmacokinetic parameters, such as maximum concentration (C max) and excretion of metabolites in urine were also significantly different between patients with CKD and controls. After 1.5 hours, numeric rating scale (NRS) scores for dizziness were significantly higher for each CKD group compared with controls (mean NRSscores: 0.7 and 1.5 vs. 0.1).

Conclusion

Total exposure to THC, CBD, and metabolites was higher in patients with CKD stages 4 and 5 compared with controls, and side effects may be more pronounced; however, the intersubject variability was high. If cannabis products are administered to patients with severe CKD, caution is needed.

Cannabis use and illicit opioid cessation among people who use drugs living with chronic pain

INTRODUCTION

Amidst the opioid overdose crisis, there is interest in cannabis use for pain management and harm reduction. We investigated the relationship between cannabis use and cessation of unregulated opioid use among people who use drugs (PWUD) living with chronic pain.

METHOD

Data for analyses were collected from three prospective cohort studies in Vancouver, Canada. All cohort participants who completed at least two study visits and reported both pain and unregulated opioid use in the past 6 months were included in the present study. We analysed the association between cannabis use frequency and opioid cessation rates using extended Cox regression models with time-updated covariates.

RESULTS

Between June 2014 and May 2022, 2340 PWUD were initially recruited and of those 1242 PWUD reported chronic pain, use of unregulated opioids and completed at least two follow-up visits. Of these 1242 participants, 764 experienced a cessation event over 1038.2 person-years resulting in a cessation rate of 28.5 per 100 person-years (95% confidence interval [CI] 25.4-31.9). Daily cannabis use was positively associated with opioid cessation (adjusted hazard ratio 1.40, 95% CI 1.08-1.81; p = 0.011). In the sex-stratified sub-analyses, daily cannabis use was significantly associated with increased rates of opioid cessation among males (adjusted hazard ratio 1.50, 95% CI 1.09-2.08; p = 0.014).

DISCUSSION AND CONCLUSIONS

Participants reporting daily cannabis use exhibited higher rates of cessation compared to less frequent users or non-users. Observed sex-specific differences in cannabis use and opioid cessation suggest potential differences in cannabis use behaviours and effects. Our findings add to the growing evidence supporting the potential benefits of cannabis use among PWUD, underlining the need for further research.

Pain Predicts Cannabis Initiation Among Emerging Adults: Results from the Population Assessment of Tobacco and Health (PATH) Study

Pain is highly prevalent among emerging adults (18-25 years old), and rates of cannabis use are increasing among this population. Research indicates pain is a unique risk factor and motivator for substance use. However, evidence for pain-cannabis use relations among emerging adults is largely cross-sectional, and the only prospective evidence focuses on the frequency, quantity, and consequences of cannabis use, not initiation. Accordingly, this is the first study to examine pain as a prospective predictor of cannabis initiation among emerging adults. Data were drawn from five annual waves of the Population Assessment of Tobacco and Health Study. Emerging adults who denied cannabis use at baseline (n = 4,185) were included in the analysis. At baseline, a tenth of emerging adults reported moderate/severe pain (≥4/10). Adjusted Cox regression analysis revealed that emerging adults with moderate/severe baseline pain were more likely to initiate cannabis use, and did so earlier over the subsequent 4 years, than those with no/low baseline pain. These findings provide initial evidence for pain as a risk factor for cannabis initiation during emerging adulthood. Future research is needed to identify mechanisms by which pain motivates cannabis initiation and to examine the utility of pain-targeted content in cannabis use prevention and intervention efforts among emerging adults.

Cannabis Dependence Among Georgian Small-Scale Cannabis Growers: Results of a Cross-Sectional Online Survey

The study aims to assess cannabis dependency among individuals who cultivate cannabis for medical and/or recreational purposes. Participants included growers who cultivated cannabis for personal use, social supply, caregiving activities, or illegal sales. Between December 2020 and August 2021, we conducted an online cross-sectional survey among Georgian cannabis growers. We used the International Cannabis Cultivation Questionnaire to measure the purpose of growing cannabis and the Severity of Dependence Scale (SDS). Logistic regression analysis was used to assess factors associated with cannabis dependency. Out of 218 cannabis growers, 193 (88.5%) grew cannabis for their personal use. Among participants, 132 (68%) used cannabis for recreational and 61 (32%) used it for medical purposes. The overall prevalence of cannabis use dependency was 37.7%. In multiple logistic regression analysis, medical users (AOR 0.39, P-value < .05) had lower odds of developing dependency compared to recreational users. Growers who used cannabis for medical purposes were more likely to consume it on a daily or almost daily basis. The majority of Georgian (illegal) cannabis growers use their products for their personal consumption, mostly for recreational purposes. This group had a higher odd of developing cannabis dependency compared to those growers who use cannabis for the medical purposes.

ART26.12, a novel fatty acid-binding protein 5 inhibitor, shows efficacy in multiple preclinical neuropathy models

BACKGROUND

Painful neuropathy is a pathological condition caused by numerous factors including diabetes, chemotherapy or cancer. ART26.12 is a novel fatty acid-binding protein 5 inhibitor, which our group showed could prevent and treat persistent pain in a preclinical model of oxaliplatin-induced peripheral neuropathy.

METHODS

In the current study, the efficacy of orally dosed ART26.12 was tested in multiple neuropathy models of different aetiology. Paw withdrawal threshold to von Frey monofilaments and latency to escape a cold plate were used as measurements of mechanical and cold sensitivity.

RESULTS

ART26.12 (25 and 50 mg/kg BID), dosed prior to the induction of paclitaxel-induced peripheral neuropathy (PIPN), reversed mechanical allodynia induced by paclitaxel in both male and female rats, and ART26.12 (50 mg/kg BID) prevented the induction of PIPN in female rats. ART26.12 (50 mg/kg BID) also had a protective effect on body weight in the PIPN model. ART26.12 (25 and 100 mg/kg BID) reversed mechanical allodynia when treating established streptozotocin-induced diabetic neuropathy in male rats. In a model of breast cancer-induced bone pain in female rats, ART26.12 (100 mg/kg BID) reversed mechanical allodynia within 1 h of dosing. In the same model, ART26.12 (25 mg/kg BID) reversed mechanical allodynia from day 4 of treatment.

CONCLUSION

Overall, these preclinical data suggest that ART26.12 is a safe and efficacious therapeutic drug for continued development towards the prevention and treatment of peripheral neuropathy.

SIGNIFICANCE STATEMENT

This work now shows that ART26.12, a novel and selective inhibitor of FABP5, can prevent and treat multiple preclinical models of peripheral neuropathy. Given its excellent safety profile, further work is warranted to develop ART26.12 as a potential therapeutic tool for pain management.

Prevalence of cannabidiol use and correlates in U.S. adults

Background

Cannabidiol (CBD) use has been increasing for its putative therapeutic potential for various health conditions. Research using a nationally representative sample is needed to examine characteristics of CBD users.

Methods

Data came from the adult sample (N=47,100) of the 2022 U.S. National Survey on Drug Use and Health. We fitted generalized linear models to examine the sociodemographic, health, other substance use, and cannabis risk perception as correlates of CBD-only use and CBD-cannabis co-use, compared to cannabis-only use.

Results

In 2022, 20.6 % and 23.0 % of U.S. adults reported using CBD and cannabis, respectively, in the preceding 12 months, and 63 % of CBD users also used cannabis. CBD use was significantly higher among women (CBD-only vs. cannabis-only use: IRR=1.43, 95 % CI=1.31-1.57), but significantly lower among Black and Hispanic individuals compared to non-Hispanic White individuals (CBD-only vs. cannabis-only use: IRR=0.71, 95 % CI=0.60-0.85 for Black individuals; IRR=0.79, 95 % CI=0.65-0.96 for Hispanic individuals). Older ages, higher SES, chronic medical conditions, mental illness, and high cannabis risk perception were also associated with higher likelihood of CBD-only use versus cannabis-only use. CBD-cannabis co-users were at most risk in terms of chronic illness, mental illness, cannabis use disorder, and other substance use problems.

Conclusions

The high prevalence of self-reported CBD use among those with physical and mental health problems warrants public health warnings about potential side effects and drug interactions. The high CBD-cannabis co-use rate also calls for more research on potential benefits and negative effects of the co-use.

Effectiveness and safety of cannabis-based products for medical use in patients with fibromyalgia syndrome: A systematic review

BACKGROUND

There is a need to explore pharmacological options for syndrome (FMS), such as medical cannabis. The aim of this systematic review was to synthesize and analyze the available information about the effectiveness/efficacy and safety of cannabis-based products for medical use (CBPMs) and cannabis-based medicines (CBMs), in patients with FMS.

METHODS

Interventional or observational studies, systematic reviews and meta-analysis regarding the effectiveness/efficacy and safety of CBPMs and CBMs in patients with FMS were retrieved from the PubMed/Medline database until April 2024. Then, the information was summarized in tables, with the type of CBPM and CBM, the method used in the study and the effective-ness/efficacy and safety outcomes.

RESULTS

19 publications were selected from the search or form the relevant references. Different CBPM and CBM were used across the studies. Also, different instruments for measuring the effectiveness were used. In general, the use of CBPMs and CBM showed an important improvement in pain, quality of life, and sleep habits. There were no serious adverse events.

CONCLUSIONS

The results show that CBMPs and CBMs could be effective and safe in patients with FMS; however, the evidence is limited and there is a need for high-quality clinical studies conducted with improved methodological design.

Cannabis combined with oxycodone for pain relief in fibromyalgia pain: a randomized clinical self-titration trial with focus on adverse events

Objectives

We determined whether adding cannabis to oxycodone for chronic non-cancer pain management could reduce treatment-related adverse effects (AEs) while maintaining effective analgesia.

Methods

In this open-label study, fibromyalgia patients aged ≥18 years were randomized to receive 5 mg oxycodone tablets (max. four times/day), 150 mg of inhaled cannabis containing 6.3% Δ9-tetrahydrocannabinol and 8% cannabidiol (max. times inhalation sessions/day), or a combination of both for 6 weeks. The primary endpoint was treatment-related adverse events, assessed using a 10-point composite adverse event (cAE) score; additionally, we recorded daily reported pain relief and daily tablet and cannabis consumption.

Results

In total, 23 patients were treated with oxycodone, 29 with cannabis, and 29 with the oxycodone/cannabis combination. Three patients from the oxycodone group (13%) and 18 patients from the cannabis groups (31%, 9 in each group) withdrew from the trial within 2-3 weeks because of the severity of AEs. There were no differences in treatment-related cAE scores among the three groups that completed the study (p = 0.70). The analgesic responder rate showed a ≥1- point reduction in pain in 50% and a ≥2-point reduction in 20% of patients, while 50% of patients experienced no treatment benefit. The combination treatment reduced oxycodone tablet consumption by 35% (p = 0.02), but it did not affect the number of cannabis inhalation sessions.

Conclusions

Cannabis combined with oxycodone offered no advantage over either treatment alone, except for a reduction in opioid tablet intake; however, the overall drug load was the highest in the combination group. Moreover, cannabis was poorly tolerated and led to treatment discontinuation in one-third of participants treated with cannabis.

Clinical Trial Registration

The trial was registered at the WHO International Clinical Trials Registry Platform (trialsearch.who.int) on July 26, 2019, identifier NL7902.

Cannabidiol Use Among Older Adults: Associations with Cannabis Use, Physical and Mental Health, and Other Substance Use

OBJECTIVES

To examine older adults' cannabidiol (CBD) use and its associations with cannabis use and physical/mental health and other substance use problems.

METHODS

Using the 2022 National Survey on Drug Use and Health (N = 10,516 respondents age 50+), we fitted generalized linear models (GLM) with Poisson and log link using CBD as the dependent variable in the 50-64 and the 65+ age groups.

RESULTS

In the 50-64 age group, 18.3% and 18.0% reported past-year CBD and cannabis, respectively, use. In the 65+ age group, the percentages were 14.3% and 8.0%. GLM results showed significant positive associations with both medical and non-medical cannabis use in both age groups. CBD use was positively associated with physical/mental health and illicit drug use problems in the 50-64 age group and with disordered psychotherapeutic drug use in the 65+ age group. Minoritized older adults had a lower likelihood of CBD use.

CONCLUSIONS

CBD use is common, more so than cannabis especially in the 65+ age group and positively correlated with both medical and nonmedical cannabis use.

CLINICAL IMPLICATIONS

Research is needed to examine therapeutic benefits and negative effects of CBD use in late life. Public health education is needed for growing numbers of older-adult CBD users.

Characterization of a Fatty Acid Amide Hydrolase (FAAH) in Hirudo Verbana

The endocannabinoid system plays a critical role in modulating both peripheral and central nervous system function. Despite being present throughout the animal kingdom, there has been relatively little investigation of the endocannabinoid system beyond traditional animal models. In this study, we report on the identification and characterization of a putative fatty acid amide hydrolase (FAAH) in the medicinal leech, Hirudo verbana. FAAH is the primary enzyme responsible for metabolizing the endocannabinoid signaling molecule arachidonoyl ethanolamide (anandamide or AEA) and therefore plays a critical role in regulating AEA levels in the nervous system. mRNA encoding Hirudo FAAH (HirFAAH) is expressed in the leech central nervous system (CNS) and sequence analysis suggests that this is an orthologue of FAAH-2 observed in vertebrates. Functionally, HirFAAH has serine hydrolase activity based on activity-based protein profiling (ABPP) studies using the fluorophosphonate probe TAMRA-FP. HirFAAH also hydrolyzes arachidonyl 7-amino, 4-methyl coumarin amide (AAMCA), a substrate specific to FAAH. Hydrolase activity during both the ABPP and AAMCA assays was eliminated by a mutation at a conserved catalytic serine. Activity was also blocked by the known FAAH inhibitor, URB597. Treatment of Hirudo ganglia with URB597 potentiated synapses made by the pressure-sensitive mechanosensory neuron (P cell), mimicking the effects of exogenously applied AEA. The Hirudo CNS has been a useful system in which to study properties of endocannabinoid modulation of nociception relevant to vertebrates. Therefore, this characterization of HirFAAH is an important contribution to comparative studies of the endocannabinoid system.

Opioids and Cannabinoids in Neurology Practice

OBJECTIVE

Opioid and cannabinoid therapies for chronic pain conditions including neuropathic pain are controversial. Understanding patient and prescribing factors contributing to risks and implementing risk mitigation strategies optimizes outcomes.

LATEST DEVELOPMENTS

The ongoing transformation from a biomedical model of pain care toward a biopsychosocial model has been accompanied by a shift away from opioid therapy for pain, in particular for chronic pain. Opioid overdose deaths and opioid use disorder have greatly increased in the last several decades, initially because of increases in opioid prescribing and more recently associated with illicit drug use, in particular fentanyl derivatives. Opioid risk mitigation strategies may reduce risks related to opioid prescribing and tapering or discontinuation. Opioid therapy guidelines from the Centers for Disease Control and Prevention have become the consensus best practice for opioid therapy. Regulatory agencies and licensing medical boards have implemented restrictions and other mandates regarding opioid therapy. Meanwhile, interest in and use of cannabinoids for chronic pain has grown in the United States.

ESSENTIAL POINTS

Opioid therapy is generally not recommended for the chronic treatment of neuropathic pain conditions. Opioids may be considered for temporary use in patients with severe pain related to selected neuropathic pain conditions (such as postherpetic neuralgia), and only as part of a multimodal treatment regimen. Opioid risk mitigation strategies include careful patient selection and evaluation, patient education and informed consent, querying the state prescription drug monitoring programs, urine drug testing, and issuance of naloxone as potential rescue medication. Close follow-up when initiating or adjusting opioid therapy and frequent reevaluation during long-term opioid therapy is required. There is evidence for the efficacy of cannabinoids for neuropathic pain, with meaningful response rates in select patient populations.

Using Medical Cannabis for Chronic Pain: A Social-Ecological Framework

Early studies suggest medical cannabis (MC) has the potential to benefit people who suffer from chronic pain by offering a less addictive alternative to opioids; however, most investigators agree more research is indicated. Today, in 2023, cannabis remains a Schedule I drug and is an illegal substance in the United States under the Controlled Substances Act of 1970. Despite this designation, as of February 2022, 37 states, three territories, and the District of Columbia allowed using cannabis products to treat certain painful medical conditions. The contradictory status of federal and state legislation regarding cannabis use has resulted in delays and restrictions on relevant research. As a result, an inadequate foundation of knowledge exists needed to inform policy, program, and practice decisions concerning MC to treat pain. Implementing and controlling access to MC is influenced by overlapping individual, interpersonal, community, and organizational influences that all fall under the umbrella of federal and state policies. Increasingly, the legalization and expanded access to MC necessitates the integration of evidence, policy, and social-ecological reality. To adequately delineate these complex factors to anticipate and plan future interventions at multiple levels, we propose a social-ecological framework (SEF) for using MC to treat pain. This SEF assumes the transactional relationship between the individual and the environment and that no single factor can predict behavior or health outcomes. Our framework illustrates five dynamic levels of analysis that interact between dimensions. Key elements and intersections are discussed at the intrapersonal, interpersonal, institutional, community, and policy levels.

Clinical Benefits and Safety of Medical Cannabis Products: A Narrative Review on Natural Extracts

Interest in medical cannabis and cannabis-based medicinal products (CBMPs) has increased greatly in recent years. Two cannabinoids are of principal importance; delta-9-tetrahydrocannabinol (∆9-THC), the primary psychoactive component, and also cannabidiol (CBD), considered non-intoxicating. Each has distinct mechanisms of action and different therapeutic potentials. CBMPs differ in their ∆9-THC and CBD components; predominantly ∆9-THC, balanced formulations with equivalent ∆9-THC and CBD elements, and CBD-predominant products. In this narrative review, we evaluate the published evidence for the clinical benefits of CBMPs and overall benefits in well-being. We also review the overall safety profile and discuss the potential for dependence with CBMPs. Evidence can be drawn from a wide range of randomized and other controlled studies and from observational real-world studies. Most data from observational registry studies are supportive of ∆9-THC-based products (∆9-THC-predominant or balanced CBMPs) in the management of chronic neuropathic pain. Balanced products are also effective in reducing spasticity in multiple sclerosis. Most CBMPs show benefit in providing symptomatic benefits in reducing anxiety, nausea, and in improving sleep, but the place of specific products is more subtle, and choice guided by specific circumstances. Symptomatic improvements are accompanied by improved quality of life and well-being. Safety data indicate that CBMPs are generally well tolerated in most patients without specific contraindications. The majority of adverse effects are non-serious, and transient; most are principally associated with ∆9-THC and are dose-dependent. In contrast to recreational cannabis use, there is little evidence from clinical studies that CBMPs have any potential for dependence.

The use of naltrexone in the treatment of chronic pain: a systematic review

This study aims to assess the efficacy of low-dose naltrexone (LDN) in treating chronic pain. We conducted a systematic review using the PICO strategy: (P) Patients with chronic pain, (I) Use of oral naltrexone, (C) Placebo or active drug and (O) Pain relief and quality of life. We included articles from PubMed, Scopus, Cochrane CENTRAL and EMBASE databases. Seven randomized clinical trials involving 406 patients were analyzed. The doses ranging from 2 to 4.5 mg once daily across all studies. Various chronic pain conditions were evaluated. The results suggest that low-dose naltrexone is not effective in managing chronic pain and improving the quality of life in patients with diverse chronic pain conditions. However, further research with larger sample sizes and standardized methodologies is necessary.

Association of cannabis use with patient-reported pain measures among adults with chronic pain in US states with medical cannabis programs

INTRODUCTION

Most Americans live in a state that has legalized cannabis as a medical treatment for pain, but it is unclear how chronic pain intensity relates to cannabis use. Our objective was to examine the association between patient-reported pain measures and cannabis among adults with chronic pain.

METHODS

This cross-sectional study of a representative sample of adults reporting chronic non-cancer pain in 36 states and DC with active medical cannabis programs from March to April 2022 assessed cannabis use for chronic pain, categorized as active (within 30 days), past (>31 days), or never use (referent). Measures were pain intensity (primary) and interference, Widespread Pain Index, and number of chronic pain diagnoses.

RESULTS

Among 1628 participants (57% female, 69% white), 352 (22%) actively used cannabis to treat chronic pain, 137 (8%) reported past cannabis use, and 1139 (70%) never used cannabis. In adjusted models, active cannabis use was associated with higher scores for pain intensity (score difference 1.03, 95% CI 0.05 to 2.02) and pain interference (score difference 1.82, 95% CI 0.99 to 2.65) compared with never use. Persons who actively used cannabis had higher Widespread Pain Index scores (score difference 0.56, 95% CI 0.26 to 0.86) and more chronic pain diagnoses (difference 0.45, 95% CI 0.06 to 0.83).

CONCLUSION

People with chronic non-cancer pain who used cannabis for pain reported non-clinically meaningful worse pain measures and greater burden of chronic pain conditions than their counterparts who never used cannabis. Alternatively, those with worse pain and greater burden of pain appear more likely to use cannabis.

Assessing suicide risk in chronic pain management: a narrative review across drug classes

INTRODUCTION

Chronic pain presents a multifaceted challenge in clinical practice, necessitating a nuanced understanding of pharmacological interventions to optimize treatment outcomes. This review provides an outline of various pharmacological agents commonly used in chronic pain management and highlights their safety considerations, particularly regarding suicide risk.

AREAS COVERED

This review discusses the role of antidepressants, anticonvulsants, GABA receptor agonists, NMDA receptor antagonists, corticosteroids, cannabis and cannabinoids, bisphosphonates, calcitonin, and alpha-2 adrenergic receptor agonists in chronic pain management. It assesses their therapeutic benefits, potential for misuse, and psychiatric adverse effects, including the risk of suicide. Each pharmacological class is evaluated in terms of its efficacy, safety profile, and considerations for clinical practice. We searched peer-reviewed English literature on the topic using the MEDLINE database without time restrictions.

EXPERT OPINION

While pharmacological interventions offer promise in alleviating chronic pain, healthcare providers must carefully weigh their benefits against potential risks, including the risk of exacerbating psychiatric symptoms and increasing suicide risk. Individualized treatment approaches, close monitoring, and multidisciplinary collaboration are essential for optimizing pain management strategies while mitigating adverse effects. Ongoing research efforts are crucial for advancing our understanding of these pharmacological interventions and refining pain management practices.

Pharmacological Treatments for Methamphetamine Use Disorder: Current Status and Future Targets

The illicit use of the psychostimulant methamphetamine (METH) is a major concern, with overdose deaths increasing substantially since the mid-2010s. One challenge to treating METH use disorder (MUD), as with other psychostimulant use disorders, is that there are no available pharmacotherapies that can reduce cravings and help individuals achieve abstinence. The purpose of the current review is to discuss the molecular targets that have been tested in assays measuring the physiological, the cognitive, and the reinforcing effects of METH in both animals and humans. Several drugs show promise as potential pharmacotherapies for MUD when tested in animals, but fail to produce long-term changes in METH use in dependent individuals (eg, modafinil, antipsychotic medications, baclofen). However, these drugs, plus medications like atomoxetine and varenicline, may be better served as treatments to ameliorate the psychotomimetic effects of METH or to reverse METH-induced cognitive deficits. Preclinical studies show that vesicular monoamine transporter 2 inhibitors, metabotropic glutamate receptor ligands, and trace amine-associated receptor agonists are efficacious in attenuating the reinforcing effects of METH; however, clinical studies are needed to determine if these drugs effectively treat MUD. In addition to screening these compounds in individuals with MUD, potential future directions include increased emphasis on sex differences in preclinical studies and utilization of pharmacogenetic approaches to determine if genetic variances are predictive of treatment outcomes. These future directions can help lead to better interventions for treating MUD.

The State of Synthetic Cannabinoid Medications for the Treatment of Pain

Synthetic cannabinoids are compounds made in the laboratory to structurally and functionally mimic phytocannabinoids from the Cannabis sativa L. plant, including delta-9-tetrahydrocannabinol (THC). Synthetic cannabinoids (SCs) can signal via the classical endogenous cannabinoid system (ECS) and the greater endocannabidiome network, highlighting their signalling complexity and far-reaching effects. Dronabinol and nabilone, which mimic THC signalling, have been approved by the Food and Drug Administration (FDA) for treating nausea associated with cancer chemotherapy and/or acquired immunodeficiency syndrome (AIDS). However, there is ongoing interest in these two drugs as potential analgesics for a variety of other clinical conditions, including neuropathic pain, spasticity-related pain, and nociplastic pain syndromes including fibromyalgia, osteoarthritis, and postoperative pain, among others. In this review, we highlight the signalling mechanisms of FDA-approved synthetic cannabinoids, discuss key clinical trials that investigate their analgesic potential, and illustrate challenges faced when bringing synthetic cannabinoids to the clinic.

[Patient-reported outcomes in chronic diseases under treatment with cannabis medicines : Analysis of the results of the Copeia survey]

BACKGROUND

The survey of Copeia captured early 2022 patient-reported outcomes (PRO) in Germany under cannabis medicinal product (CAM) therapy, with particular attention to symptoms, symptom changes, indications, side effects, dosages, and cost bearers.

GOAL

This study investigated the question of whether associations emerge from the results that could play a role in the indication and treatment monitoring of CAM in chronically ill patients.

MATERIALS AND METHODS

A standardized questionnaire was administered online nationwide in dialogue form over a 15-week period to collect itemized symptoms and PRO. Recruitment was supported by pharmacies, prescribing physicians, and patient associations. Inclusion criteria included physician-prescribed CAM therapy.

RESULTS AND DISCUSSION

Of 1582 participants, 1030 data sets (65%) could be completely analyzed. There was a heterogeneous patient population, whose common feature was disease chronicity. The frequency distribution of symptoms showed a homogeneous pattern for the respective indications, in which the most frequent six (pain 71%, sleep disturbance 64%, stress/tension 52%, inner restlessness 52%, depressive mood 44% and muscle tension 43%) seem to have a special significance. According to subjective assessment, quality of life improved significantly in 84% of all participating patients.

CONCLUSION

A symptom matrix (SMX) composed of different symptoms seems to play a special role in CAM therapy to improve the quality of life of chronically ill patients, regardless of the underlying disease. The SMX could contribute to the identification of an indication and to targeted treatment monitoring.

Understanding the epidemiology and perceived efficacy of cannabis use in patients with chronic musculoskeletal pain

BACKGROUND

The belief that cannabis has analgesic and anti-inflammatory properties continues to attract patients with chronic musculoskeletal (MSK) pain towards its use. However, the role that cannabis will play in the management of chronic MSK pain remains to be determined. This study examined 1) the rate, patterns of use, and self-reported efficacy of cannabis use among patients with chronic MSK pain and 2) the interest and potential barriers to cannabis use among patients with chronic MSK pain not currently using cannabis.

METHODS

Self-reported cannabis use and perceived efficacy were prospectively collected from chronic MSK pain patients presenting to the Orthopaedic Clinic at the University Health Network, Toronto, Canada. The primary dependent variable was current or past use of cannabis to manage chronic MSK pain; bivariate and multivariable logistic regression were used to identify patient characteristics independently associated with this outcome. Secondary outcomes were summarized descriptively, including self-perceived efficacy among cannabis users, and interest as well as barriers to cannabis use among cannabis non-users.

RESULTS

The sample included 629 patients presenting with chronic MSK pain (mean age: 56±15.7 years; 56% female). Overall, 144 (23%) reported past or present cannabis use to manage their MSK pain, with 63.7% perceiving cannabis as very or somewhat effective and 26.6% considering it as slightly effective. The strongest predictor of cannabis use in this study population was a history of recreational cannabis use (OR 12.7, p<0.001). Among cannabis non-users (N=489), 65% expressed interest in using cannabis to manage their chronic MSK pain, but common barriers to use included lack of knowledge regarding access, use and evidence, and stigma.

CONCLUSIONS

One in five patients presenting to an orthopaedic surgeon with chronic MSK pain are using or have used cannabis with the specific intent to manage their pain, and most report it to be effective. Among non-users, two-thirds reported an interest in using cannabis to manage their MSK pain, but common barriers to use existed. Future double-blind placebo-controlled trials are required to understand if this reported efficacy is accurate, and what role, if any, cannabis may play in the management of chronic MSK pain.

Pathology of pain and its implications for therapeutic interventions

Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.

Chronic pain, a narrative review for the internist in 2024

Chronic pain is a complex and pervasive condition that profoundly affects individuals physically, emotionally, and socially. This narrative review aims to provide internists and healthcare professionals with a comprehensive overview of chronic pain, its various types, pathophysiology, epidemiology, clinical presentation, evaluation tools, and the burden it imposes on patients. We discuss the importance of recognizing chronic pain as a legitimate condition and the need for a compassionate, individualized approach to management. The review highlights the role of both pharmacological and non-pharmacological interventions in treating chronic pain, emphasizing the value of reducing pain, improving function, enhancing quality of life, and minimizing medication dependence. Additionally, we touch upon the promising future of pain treatment, including advancements in technology and personalized medicine. While not a comprehensive systematic review, this article serves as a valuable resource for healthcare providers seeking to understand, manage, and treat chronic pain effectively in their daily practice.

How Biodegradable Polymers Can be Effective Drug Delivery Systems for Cannabinoids? Prospectives and Challenges

Cannabinoids are compounds found in and derived from the Cannabis plants that have become increasingly recognised as significant modulating factors of physiological mechanisms and inflammatory reactions of the organism, thus inevitably affecting maintenance of homeostasis. Medical Cannabis popularity has surged since its legal regulation growing around the world. Numerous promising discoveries bring more data on cannabinoids' pharmacological characteristics and therapeutic applications. Given the current surge in interest in the medical use of cannabinoids, there is an urgent need for an effective method of their administration. Surpassing low bioavailability, low water solubility, and instability became an important milestone in the advancement of cannabinoids in pharmaceutical applications. The numerous uses of cannabinoids in clinical practice remain restricted by limited administration alternatives, but there is hope when biodegradable polymers are taken into account. The primary objective of this review is to highlight the wide range of indications for which cannabinoids may be used, as well as the polymeric carriers that enhance their effectiveness. The current review described a wide range of therapeutic applications of cannabinoids, including pain management, neurological and sleep disorders, anxiety, and cancer treatment. The use of these compounds was further examined in the area of dermatology and cosmetology. Finally, with the use of biodegradable polymer-based drug delivery systems (DDSs), it was demonstrated that cannabinoids can be delivered specifically to the intended site while also improving the drug's physicochemical properties, emphasizing their utility. Nevertheless, additional clinical trials on novel cannabinoids' formulations are required, as their full spectrum therapeutical potential is yet to be unravelled.

Pierre M, Belle-Isle L, Gagnon M, Bevan S, Sanchez T, Arlt S, Monahan-Ellison M, O'Hara J, Boivin M, Costiniuk C. Clinical Practice Guidelines for Cannabis and Cannabinoid-Based Medicines in the Management of Chronic Pain and Co-Occurring Conditions

Background: One in five individuals live with chronic pain globally, which often co-occurs with sleep problems, anxiety, depression, and substance use disorders. Although these conditions are commonly managed with cannabinoid-based medicines (CBM), health care providers report lack of information on the risks, benefits, and appropriate use of CBM for therapeutic purposes. Aims: We present these clinical practice guidelines to help clinicians and patients navigate appropriate CBM use in the management of chronic pain and co-occurring conditions. Materials and Methods: We conducted a systematic review of studies investigating the use of CBM for the treatment of chronic pain. Articles were dually reviewed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Clinical recommendations were developed based on available evidence from the review. Values and preferences and practical tips have also been provided to support clinical application. The GRADE system was used to rate the strength of recommendations and quality of evidence. Results: From our literature search, 70 articles met inclusion criteria and were utilized in guideline development, including 19 systematic reviews and 51 original research studies. Research typically demonstrates moderate benefit of CBM in chronic pain management. There is also evidence for efficacy of CBM in the management of comorbidities, including sleep problems, anxiety, appetite suppression, and for managing symptoms in some chronic conditions associated with pain including HIV, multiple sclerosis, fibromyalgia, and arthritis. Conclusions: All patients considering CBM should be educated on risks and adverse events. Patients and clinicians should work collaboratively to identify appropriate dosing, titration, and administration routes for each individual. Systematic Review Registration: PROSPERO no. 135886.

Effects of Medical Cannabis Certification on Hospital Use by Individuals with Sickle Cell Disease

Context: Retrospective study of 36 individuals with sickle cell disease (SCD) certified for medical cannabis. Objective: We sought to examine whether medical cannabis certification was associated with a change in utilization of acute care medical services for patients with SCD. Methods: We identified patients with SCD certified for medical cannabis use between July 2014 and December 2021 using the New York State Prescription Monitoring Program (NYS PMP) and cross-matching to our electronic medical record. We estimated the mean incidences of Emergency Department (ED) visits, hospital admissions, inpatient days, and total acute encounters for SCD-related pain per month pre- and post-medical cannabis certification and used paired t-tests to assess the statistical significance of changes in hospital use. We stratified incidence based on whether patients had received a bone marrow transplant (BMT) at any point before or during the research period, since BMT is potentially an important covariate. Recertification rates and patients' reasons for choosing to recertify were qualitatively investigated through retrospective chart review. Results: The incidence of ED visits, hospital admissions, and total acute encounters per month for SCD-related pain decreased pre- to post-certification (p=0.02; p=0.02; p=0.01). These decreases lost statistical significance after stratifying patients based on BMT history. There was no statistically significant change in the number of days per month patients spent hospitalized in either the primary analysis or after stratification by BMT status. Forty-four percent of patients chose to be recertified. Thirty-six percent of patients cited concerns regarding the cost of medical cannabis. Conclusion: Our study did not show a statistically significant relationship between certification for medical cannabis and hospital use after addressing BMT history as a potentially important covariate. However, we were likely underpowered to detect any existing difference after patient data were stratified due to our small sample size. Regardless, 44% of patients chose to be recertified, indicating a perceived benefit and utility in further investigation of medical cannabis for this population with a larger analytic sample. Patient-reported benefits were improvement of pain and other symptoms, decreased opiate requirements, and decreased side effects compared to opiates.

Amyotrophic Lateral Sclerosis and Pain: A Narrative Review from Pain Assessment to Therapy

Amyotrophic lateral sclerosis (ALS) is the most frequent neurodegenerative disease of the motor system that affects upper and lower motor neurons, leading to progressive muscle weakness, spasticity, atrophy, and respiratory failure, with a life expectancy of 2-5 years after symptom onset. In addition to motor symptoms, patients with ALS have a multitude of nonmotor symptoms; in fact, it is currently considered a multisystem disease. The purpose of our narrative review is to evaluate the different types of pain, the correlation between pain and the disease's stages, the pain assessment tools in ALS patients, and the available therapies focusing above all on the benefits of cannabis use. Pain is an underestimated and undertreated symptom that, in the last few years, has received more attention from research because it has a strong impact on the quality of life of these patients. The prevalence of pain is between 15% and 85% of ALS patients, and the studies on the type and intensity of pain are controversial. The absence of pain assessment tools validated in the ALS population and the dissimilar study designs influence the knowledge of ALS pain and consequently the pharmacological therapy. Several studies suggest that ALS is associated with changes in the endocannabinoid system, and the use of cannabis could slow the disease progression due to its neuroprotective action and act on pain, spasticity, cramps, sialorrhea, and depression. Our research has shown high patients' satisfaction with the use of cannabis for the treatment of spasticity and related pain. However, especially due to the ethical problems and the lack of interest of pharmaceutical companies, further studies are needed to ensure the most appropriate care for ALS patients.

Therapeutic use of medical Cannabis in neurological diseases: a clinical update

The use of medical Cannabis has increased in recent years due to changing legal circumstances in many countries. Approval exists only for a few neurological conditions such as rare forms of epilepsy or spasticity in multiple sclerosis. Beyond that, however, medical Cannabis is used for a wide range of neurological conditions and symptoms. In Germany, in parallel with new legislation that has simplified the prescription of medical Cannabis, an accompanying survey has been implemented for which initial data are now available. In this context, our review provides an overview of the evidence for the therapeutic use of medical Cannabis in neurology, the potential benefits, and side effects.

Comparing Cannabis Use for Pain to Use for Other Reasons in Primary Care Patients

BACKGROUND

Medical cannabis is commonly used for chronic pain, but little is known about differences in characteristics, cannabis use patterns, and perceived helpfulness among primary care patients who use cannabis for pain versus nonpain reasons.

METHODS

Among 1688 patients who completed a 2019 cannabis survey administered in a health system in Washington state, where recreational use is legal, participants who used cannabis for pain (n = 375) were compared with those who used cannabis for other reasons (n = 558) using survey and electronic health record data. We described group differences in participant characteristics, use patterns, and perceptions and applied adjusted multinomial logistic and modified Poisson regression.

RESULTS

Participants who used cannabis for pain were significantly more likely to report using applied (50.7% vs 10.6%) and beverage cannabis products (19.2% vs 11.6%), more frequent use (47.1% vs 33.1% for use ≥2 times per day; 81.6% vs 69.7% for use 4 to 7 days per week), and smoking tobacco cigarettes (19.2% vs 12.2%) than those who used cannabis for other reasons. They were also significantly more likely to perceive cannabis as very/extremely helpful (80.5% vs 72.7%), and significantly less likely to use cannabis for nonmedical reasons (4.8% vs 58.8%) or report cannabis use disorder symptoms (51.7% vs 61.1%).

DISCUSSION

Primary care patients who use cannabis for pain use it more frequently, often in applied and ingested forms, and have more co-use of tobacco, which may differentially impact safety and effectiveness. These findings suggest the need for different approaches to counseling in clinical care.

Applications of Cannabinoids in Neuropathic Pain: An Updated Review

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.

The Therapeutic Potential and Molecular Mechanisms Underlying the Neuroprotective Effects of Sativex® - A Cannabis-derived Spray

Sativex is a cannabis-based medicine that comes in the form of an oromucosal spray. It contains equal amounts of Δ9-tetrahydrocannabinol and cannabidiol, two compounds derived from cannabis plants. Sativex has been shown to have positive effects on symptoms of amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and sleep disorders. It also has analgesic, antiinflammatory, antitumoral, and neuroprotective properties, which make it a potential treatment option for other neurological disorders. The article reviews the results of recent preclinical and clinical studies that support the therapeutic potential of Sativex and the molecular mechanisms behind its neuroprotective benefits in various neurological disorders. The article also discusses the possible advantages and disadvantages of using Sativex as a neurotherapeutic agent, such as its safety, efficacy, availability, and legal status.

Advances in diagnosis and management of distal sensory polyneuropathies

Distal sensory polyneuropathy (DSP) is characterised by length-dependent, sensory-predominant symptoms and signs, including potentially disabling symmetric chronic pain, tingling and poor balance. Some patients also have or develop dysautonomia or motor involvement depending on whether large myelinated or small fibres are predominantly affected. Although highly prevalent, diagnosis and management can be challenging. While classic diabetes and toxic causes are well-recognised, there are increasingly diverse associations, including with dysimmune, rheumatological and neurodegenerative conditions. Approximately half of cases are initially considered idiopathic despite thorough evaluation, but often, the causes emerge later as new symptoms develop or testing advances, for instance with genetic approaches. Improving and standardising DSP metrics, as already accomplished for motor neuropathies, would permit in-clinic longitudinal tracking of natural history and treatment responses. Standardising phenotyping could advance research and facilitate trials of potential therapies, which lag so far. This review updates on recent advances and summarises current evidence for specific treatments.

Medical Cannabis Use and Its Impact on Health Among Older Adults: Recent Research Findings and Future Directions

Purpose of Review

With the rapidly changing landscape of state level legalization of cannabis, older adults have become one of the fastest growing populations seeking medical cannabis (MC). However, research evidence on the risks and benefits of MC use in this population remains limited. This review aims to synthesize recent literature on the impacts of MC use in older adults and identify critical knowledge gaps to be addressed in future research.

Recent Findings

Recent literature showed that older adults often face financial and/or educational barriers and stigma associated with MC access. Emerging data showed that MC may have therapeutic effects on symptoms of conditions such as chronic pain, insomnia, anxiety/depression, dementia, nausea, and vomiting. However, available evidence is inconsistent and tends to rely on self-report and uncontrolled studies. While some adverse events associated with MC use were reported, it is generally well tolerated in older adults. Neurocognitive and psychological consequences and cardiovascular risks have been reported but again only in limited studies with inconsistent findings.

Summary

There is a need for more systematic and rigorous research on MC in older adults to determine its safety and efficacy. Research on dosing procedures and product characteristics, as well as how these may impact health outcomes, is crucial. More consistent evidence is needed to inform policy changes and patient/physician education to minimize potential risks and optimize benefits among older adults seeking MC as an alternative treatment.

Efficacy and safety of TRPV1-related preparations in the treatment of inflammatory arthralgia

BACKGROUND

Currently, medications for the treatment of inflammatory arthralgia are limited. The role and safety of transient receptor potential vanilloid subtype 1 (TRPV1)-related preparations in reducing inflammatory arthralgia have not yet been fully established. Thus, we aimed to review the efficacy and safety of TRPV1-related preparations for the treatment of inflammatory arthralgia.

METHODS

We searched PubMed, Web of Science, Cochrane, and Embase databases for relevant studies, and the primary outcome was pain score (VAS, PI, NRS, and WOMAC).

RESULTS

Six randomized controlled trials involving 481 patients were analyzed. Patients with inflammatory arthralgia who received TRPV1-related preparations had lower pain scores after treatment than those who received placebo or nonsteroidal anti-inflammatory agents (standardized mean difference = -0.525; 95% confidence interval [CI], -0.789 to -0.261; P < .001). There was no significant difference in the incidence of total adverse reactions between the TRPV1-related preparations and control groups (relative risk = 1.225; 95% CI, 0.685 to 2.191; P = .494).

CONCLUSION

TRPV1-related preparations are clinically safe and effective in the treatment of inflammatory arthralgia and are superior to placebo or nonsteroidal drugs. This may be the preferred treatment for patients with inflammatory arthralgia.

Effectiveness of alpha-lipoic acid in patients with neuropathic pain associated with type I and type II diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

This systematic review explores the most current evidence regarding the mechanisms of neuropathic pain in patients with different types of diabetes and how this pain affects different functional and structural components of the neuroanatomical pain pathways. The review also seeks to provide guidelines for the best approach and treatment for patients experiencing this type of pain. The objective is to determine the effectiveness of alpha-lipoic acid (ALA) in improving functional and symptomatic outcomes in patients with diabetes mellitus type I and type II.

OBJECTIVE

To determine the effectiveness of alpha-lipoic acid (ALA) in improving functional and symptomatic outcomes in patients with diabetes mellitus type I and type II.

METHODS

We systematically search MEDLINE (via PubMed), EMBASE, SCOPUS, the Cochrane Central Register of Controlled Trials, the Cumulative Index to Nursing and Allied Health Literature, and Web of Science databases.

RESULTS

The findings of this review show that different forms of ALA do not present statistically significant changes for any of the scales included, including total symptom score (standardized mean difference [SMD] = -3.59, confidence interval [CI] = -4.16 to -3.02, and P < .00001), neuropathy impairment score (SMD = -1.42, CI = -3.68 to 0.84, and P = .22), and neuropathy symptom checklist (SMD = -0.09, CI = -0.15 to -0.02, and P = .01).

CONCLUSION

In comparison to the use of a placebo, the findings suggest that ALA does not exhibit significant differences in terms of pain reduction and different functional scales. Moreover, no specific dosages are identified to support the use of ALA for the reduction of neuropathic pain.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

Cannabis for Healing in a Native Community Clinic: Development and Results from an Informatics Research Tool

This paper describes how the Puyallup Tribe created a clinic specializing in cannabis-based treatments and partnered with a university research team to assess the impacts of cannabis on patient outcomes. Clinic leaders and research team co-developed an informatics research tool that included survey questions about patient demographics, cannabis use, and measures of pain, depression, anxiety, other substance use, and trauma. Over the first 2.5 years of operations, 69 patients completed a survey. Participants were an average age of 50 years old (SD = 16.7), female (77.6%) and American Indian/Alaska Native (61.5%) with more than 12 years of education (66.7%). Over 77% of the participants used either cannabidiol-dominant (CBD) alone or both CBD and Tetrahydrocannabinol-dominant (THC) products, nearly 23% used neither CBD nor THC products. Most came to the clinic for a pain relief appointment (70.3%). Compared to the general population, participants experienced more pain-related comorbidities, such as anxiety, fatigue, sleep, and pain, and fewer physical functioning capabilities. Over half reported symptoms consistent with depressive or post-traumatic stress disorder. The informatics research tool was successfully integrated into a unique Tribally owned medical clinic.

Fibromyalgia interventions, obstacles and prospects: narrative review

This review aims to increase awareness and improve understanding, diagnosis, and management of fibromyalgia - a complex, distressing health challenge that significantly impacts people's lives due to its variable nature and lack of clear diagnostic markers. Healthcare professionals must assist those with this condition and improve their general quality of life. Further, they can do a lot to improve the lives of people with Fibromyalgia by resolving diagnostic hurdles, promoting collaboration, supporting patient advocacy, advancing medical technology, and adopting novel approaches.

Therapeutic Approach for Trigeminal Neuralgia: A Systematic Review

This umbrella review aimed to determine the various drugs used to treat trigeminal neuralgia (TN) and to evaluate their efficacies as well as side effects by surveying previously published reviews. An online search was conducted using PubMed, CRD, EBSCO, Web of Science, Scopus, and the Cochrane Library with no limits on publication date or patients' gender, age, and ethnicity. Reviews and meta-analyses of randomized controlled trials pertaining to drug therapy for TN, and other relevant review articles added from their reference lists, were evaluated. Rapid reviews, reviews published in languages other than English, and reviews of laboratory studies, case reports, and series were excluded. A total of 588 articles were initially collected; 127 full-text articles were evaluated after removing the duplicates and screening the titles and abstracts, and 11 articles were finally included in this study. Except for carbamazepine, most of the drugs had been inadequately studied. Carbamazepine and oxcarbazepine continue to be the first choice for medication for classical TN. Lamotrigine and baclofen can be regarded as second-line drugs to treat patients not responding to first-line medication or for patients having intolerable side effects from carbamazepine. Drug combinations using carbamazepine, baclofen, gabapentin, ropivacaine, tizanidine, and pimozide can yield satisfactory results and improve the tolerance to the treatment. Intravenous lidocaine can be used to treat acute exaggerations and botulinum toxin-A can be used in refractory cases. Proparacaine, dextromethorphan, and tocainide were reported to be inappropriate for treating TN. Anticonvulsants are successful in managing trigeminal neuralgia; nevertheless, there have been few studies with high levels of proof, making it challenging to compare or even combine their results in a statistically useful way. New research on other drugs, combination therapies, and newer formulations, such as vixotrigine, is awaited. There is conclusive evidence for the efficacy of pharmacological drugs in the treatment of TN.

Sex differences in acute delta-9-tetrahydrocannabinol (Δ9-THC) response and tolerance as a function of mouse strain

Cannabinoids are increasingly used to alleviate pain; however, tolerance to their antinociceptive effects, including those of delta-9-tetrahydrocannabinol (Δ9-THC), may limit their therapeutic utility. With more women than men using medical cannabis for pain relief, it is crucial to understand how sex influences cannabinoid-mediated antinociception and tolerance. Though studies in rats consistently find females are more sensitive to the acute antinociceptive effects of cannabinoids, our work with mice consistently finds the converse. The present study examined whether our observed sex differences in Δ9-THC-induced antinociception and tolerance are consistent across multiple mouse strains or are strain-dependent. Male and female C57BL/6J (B6), DBA/2, AKR, and CBA/J mice were assessed for differences in acute Δ9-THC-induced antinociception and hypothermia prior to and following seven days of once-daily Δ9-THC administration. Consistent with our previous findings, male B6 mice were more sensitive to the acute antinociceptive effects of Δ9-THC than female littermates, an effect which dissipated with age. B6 males had decreased cannabinoid expression in the PAG compared to females. While DBA and CBA female mice showed increased Δ9-THC-antinociception compared to male littermates at 30 and 10 mg/kg Δ9-THC, respectively, these differences were less pronounced at higher doses, revealing that dose of Δ9-THC may also be important. Overall, CBA mice were more sensitive to Δ9-THC-induced antinociception while AKR mice were less responsive. These studies highlight the therapeutic potential of Δ9-THC in pain management and underscore the importance of considering not only Δ9-THC dose as a function of sex, but potentially genetic differences when evaluating their clinical utility.

Looking Back, Moving Forward in Pain Medicine

Pain is an ancient medical complaint and a clinical riddle that has never been entirely solved. Looking back into history was the springboard to a look into the future of pain medicine. This article was based on a series of presentations given in a recent congress (May 2023) and represents the research, views, and opinions of the authors. Opium has been used for millennia to treat pain, but when it gained broad use in the United States in the 1980s and 1990s, it was so vastly overprescribed and mis-prescribed that it led to a public health crisis. This, in turn, led to the reaction where opioids at times were under-prescribed, leaving out many patients who may have benefited from opioids while leaving many legacy pain patients to manage withdrawal on their own and with few analgesic options. Cannabinoids (CB) were likewise widely used for various conditions, including pain, but were outlawed in the 20th century, only to be brought back as a potential analgesic agent. Interventional pain medicine is a developing discipline and has reinforced the concept of the interdisciplinary pain clinic. It plays an increasingly important part in modern medicine overall, especially with the support of ultrasound, for both diagnosis and therapy. Today, the views about pain have changed. Anyone has accepted that pain is not purely a physical phenomenon but a biopsychosocial phenomenon that occurs within a cultural context. Pain management remains a small but vitally important medical subspecialty that is critical from a functional enablement and population health perspective, which is helping to navigate new therapeutic targets, new drugs and routes of administration, greater understanding of pain psychology, and new technologies. Pain control today means early intervention, functional enablement through pain alleviation, educating patients about pain management, and minimizing the transition from acute to chronic pain.

A Brief Review on the Novel Therapies for Painful Diabetic Neuropathy

PURPOSE OF REVIEW

Almost half of people diagnosed with diabetes mellitus will develop painful diabetic neuropathy (PDN), a condition greatly impacting quality of life with complicated pathology. While there are different FDA approved forms of treatment, many of the existing options are difficult to manage with comorbities and are associated with unwanted side effects. Here, we summarize the current and novel treatments for PDN.

RECENT FINDINGS

Current research is exploring alternative pain management treatments from the first line options of pregabalin, gabapentin, duloxetine, and amitriptyline which often have side effects. The use of FDA approved capsaicin and spinal cord stimulators (SCS) has been incredibly beneficial in addressing this. In addition, new treatments looking at different targets, such as NMDA receptor and the endocannabinoid system, show promising results. There are several treatment options that have been shown to be successful in helping treat PDN, but often require adjunct treatment or alterations due to side effects. While there is ample research for standard medications, treatments such as palmitoylethanolamide and endocannabinoid targets have extremely limited clinical trials. We also found that many studies did not evaluate additional variables other than pain relief, such as functional changes nor were there consistent measurement methods. Future research should continue trials comparing treatment efficacies along with more quality of life measures.

Cannabis use among cancer survivors in 22 states: Results from the Behavioral Risk Factor Surveillance System, 2020

BACKGROUND

This study identified factors associated with recent cannabis use and cannabis use for medical purposes among cancer survivors relative to individuals without a history of cancer.

METHODS

Data from the Behavioral Risk Factor Surveillance System were analyzed for the 22 states completing the optional cannabis module in 2020. Weighted multiple logistic regression was performed to explore variables associated with past 30-day cannabis use and cannabis use for medical purposes, stratified by history of cancer. Covariates included state-level cannabis policy, sociodemographic characteristics, health status indicators, and substance use.

RESULTS

Cannabis use was lower among cancer survivors compared to individuals with no history of cancer (7.57% vs. 10.83%). However, a higher proportion of cancer survivors reported use for medical purposes (82.23% vs. 62.58%). After adjusting for state-level policy, biological sex, age, educational attainment, self-reported race/ethnicity, home ownership, mental health status and physical health status, current smoking (odds ratio [OR], 5.14 vs. 3.74) and binge drinking (OR, 2.71 vs. 2.69) were associated with cannabis use in both groups. Characteristics associated with medical cannabis use varied for the two groups; however, daily use (20-30 days; OR, 1.72 vs. 2.43) was associated with cannabis use for medical purposes in both groups after adjusting for other variables in the model.

CONCLUSIONS

A high proportion of individuals report cannabis use for medical purposes with higher rates among cancer survivors. Findings support the urgent need for ongoing cannabis research to better understand and inform its use for medical purposes, as well as the development of high-quality standardized education materials and clinical practice guidelines.

Effects of U.S. State Medical Cannabis Laws on Treatment of Chronic Noncancer Pain

BACKGROUND

State medical cannabis laws may lead patients with chronic noncancer pain to substitute cannabis in place of prescription opioid or clinical guideline-concordant nonopioid prescription pain medications or procedures.

OBJECTIVE

To assess effects of state medical cannabis laws on receipt of prescription opioids, nonopioid prescription pain medications, and procedures for chronic noncancer pain.

DESIGN

Using data from 12 states that implemented medical cannabis laws and 17 comparison states, augmented synthetic control analyses estimated laws' effects on receipt of chronic noncancer pain treatment, relative to predicted treatment receipt in the absence of the law.

SETTING

United States, 2010 to 2022.

PARTICIPANTS

583 820 commercially insured adults with chronic noncancer pain.

MEASUREMENTS

Proportion of patients receiving any opioid prescription, nonopioid prescription pain medication, or procedure for chronic noncancer pain; volume of each treatment type; and mean days' supply and mean morphine milligram equivalents per day of prescribed opioids, per patient in a given month.

RESULTS

In a given month during the first 3 years of law implementation, medical cannabis laws led to an average difference of 0.05 percentage points (95% CI, -0.12 to 0.21 percentage points), 0.05 percentage points (CI, -0.13 to 0.23 percentage points), and -0.17 percentage points (CI, -0.42 to 0.08 percentage points) in the proportion of patients receiving any opioid prescription, any nonopioid prescription pain medication, or any chronic pain procedure, respectively, relative to what we predict would have happened in that month had the law not been implemented.

LIMITATIONS

This study used a strong nonexperimental design but relies on untestable assumptions involving parallel counterfactual trends. Statistical power is limited by the finite number of states. Results may not generalize to noncommercially insured populations.

CONCLUSION

This study did not identify important effects of medical cannabis laws on receipt of opioid or nonopioid pain treatment among patients with chronic noncancer pain.

PRIMARY FUNDING SOURCE

National Institute on Drug Abuse.

Interventions for treating pain and disability in adults with complex regional pain syndrome- an overview of systematic reviews

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic pain condition that usually occurs in a limb following trauma or surgery. It is characterised by persisting pain that is disproportionate in magnitude or duration to the typical course of pain after similar injury. There is currently no consensus regarding the optimal management of CRPS, although a broad range of interventions have been described and are commonly used. This is the first update of the original Cochrane review published in Issue 4, 2013.

OBJECTIVES

To summarise the evidence from Cochrane and non-Cochrane systematic reviews of the efficacy, effectiveness, and safety of any intervention used to reduce pain, disability, or both, in adults with CRPS.

METHODS

We identified Cochrane reviews and non-Cochrane reviews through a systematic search of Ovid MEDLINE, Ovid Embase, Cochrane Database of Systematic Reviews, CINAHL, PEDro, LILACS and Epistemonikos from inception to October 2022, with no language restrictions. We included systematic reviews of randomised controlled trials that included adults (≥18 years) diagnosed with CRPS, using any diagnostic criteria.  Two overview authors independently assessed eligibility, extracted data, and assessed the quality of the reviews and certainty of the evidence using the AMSTAR 2 and GRADE tools respectively. We extracted data for the primary outcomes pain, disability and adverse events, and the secondary outcomes quality of life, emotional well-being, and participants' ratings of satisfaction or improvement with treatment.  MAIN RESULTS: We included six Cochrane and 13 non-Cochrane systematic reviews in the previous version of this overview and five Cochrane and 12 non-Cochrane reviews in the current version. Using the AMSTAR 2 tool, we judged Cochrane reviews to have higher methodological quality than non-Cochrane reviews. The studies in the included reviews were typically small and mostly at high risk of bias or of low methodological quality. We found no high-certainty evidence for any comparison.  There was low-certainty evidence that bisphosphonates may reduce pain intensity post-intervention (standardised mean difference (SMD) -2.6, 95% confidence interval (CI) -1.8 to -3.4, P = 0.001; I2 = 81%; 4 trials, n = 181) and moderate-certainty evidence that they are probably associated with increased adverse events of any nature (risk ratio (RR) 2.10, 95% CI 1.27 to 3.47; number needed to treat for an additional harmful outcome (NNTH) 4.6, 95% CI 2.4 to 168.0; 4 trials, n = 181).  There was moderate-certainty evidence that lidocaine local anaesthetic sympathetic blockade probably does not reduce pain intensity compared with placebo, and low-certainty evidence that it may not reduce pain intensity compared with ultrasound of the stellate ganglion. No effect size was reported for either comparison. There was low-certainty evidence that topical dimethyl sulfoxide may not reduce pain intensity compared with oral N-acetylcysteine, but no effect size was reported. There was low-certainty evidence that continuous bupivacaine brachial plexus block may reduce pain intensity compared with continuous bupivacaine stellate ganglion block, but no effect size was reported. For a wide range of other commonly used interventions, the certainty in the evidence was very low and provides insufficient evidence to either support or refute their use. Comparisons with low- and very low-certainty evidence should be treated with substantial caution. We did not identify any RCT evidence for routinely used pharmacological interventions for CRPS such as tricyclic antidepressants or opioids.

AUTHORS' CONCLUSIONS

Despite a considerable increase in included evidence compared with the previous version of this overview, we identified no high-certainty evidence for the effectiveness of any therapy for CRPS. Until larger, high-quality trials are undertaken, formulating an evidence-based approach to managing CRPS will remain difficult. Current non-Cochrane systematic reviews of interventions for CRPS are of low methodological quality and should not be relied upon to provide an accurate and comprehensive summary of the evidence.