Cannabis in Pain Treatment: Clinical and Research Considerations

Is a Low Dosage of Medical Cannabis Effective for Treating Pain Related to Fibromyalgia? A Pilot Study and Systematic Review

Background and Objectives: Fibromyalgia is a multifaceted and frequently misunderstood chronic pain disease marked by widespread musculoskeletal pain and cognitive/somatic dysfunction. This trial aims to contribute to the existing knowledge on treating fibromyalgia (FM) with medical cannabis (Cannabis sativa L.) and explore a safer and more effective cannabis administration method. The goal is to provide evidence-based findings that can guide alternative treatment options for FM patients by assessing a pilot study. Materials and Methods: The trial was performed at the pain therapy unit of the San Carlo Hospital (Potenza, Italy) by administrating to 30 FM patients 100 mg/day of Bedrocan® (Bedrocan International, Veendam, The Netherlands) as a decoction. The Numerical Rating Scale (NRS) and SF-12 short-form health questionnaire were used to evaluate pain intensity and the quality of life at the beginning of the study and the 6th-month follow-up. A systematic review of all clinical studies investigating the use of cannabis to reduce FM was also undertaken to place this study in the context of the existing evidence base. Results: Pain intensity evaluated with the NRS lowered from a median of 8 [95% CI 7.66-8.54] at a baseline to a median of 4 (95% CI 3.28-4.79) after 6 months of follow-up (p-value < 0.001; t-test). Similarly, significant physical and mental state improvement, evaluated with the SF-12 questionnaire, was found in 96.67% and 82.33% of patients, respectively (95% CI 44.11-51.13 for the physical state, and 53.48-58.69 for mental state assessed after the 6th-month follow-up; p-value < 0.001; t-test). The systematic analysis of the literature identified 10 clinical trials concerning the treatment of fibromyalgia with cannabis. Conclusions: Considering results from the present pilot study and systematic review, it is possible to assume that medical cannabis may be considered an alternative therapy for FM patients who do not respond to conventional pharmacological therapy.

Cannabis use by individuals with spinal cord injury in the UK: a call for improved patient education and physician awareness for pain and spasticity management

STUDY DESIGN

Prospective observational qualitative study.

OBJECTIVE

Cannabis is used by patients for the treatment of chronic pain, spasticity, sleep issues or mood disorders such as anxiety and depression. Since 2018, it has been authorised in the United Kingdom for medical use as an unlicensed medicine. This study aims to determine if patients are using cannabis for the management of symptoms related to spinal cord injury, and if so, whether they are using medical or illicit cannabis.

METHODS

Spinal cord injury patients from the Yorkshire Regional Spinal Injuries Centre and SPINE Community in the United Kingdom were surveyed. Participants were sent a 7-point electronic survey. All results were anonymous, and confidentiality was maintained throughout the process.

RESULTS

In total, 223 patients completed the survey. Not all patients answered every question. Of those who responded 65.35% (n = 132) were paraplegic and 34.65% (n = 70) were tetraplegic. Patients were suffering from chronic pain (longer than 3 months), spasticity, loss of/difficulty in sleeping or anxiety/depression. Almost 15% (14.93%, n = 33 out of 221) used cannabis to manage their symptoms, out of those the majority used street cannabis (79.41%, n = 27 out of 34) were using street cannabis.

CONCLUSION

This study demonstrates that there are spinal cord injury patients in the UK using cannabis to treat their symptoms. A majority appear to be using illicit cannabis. Given that cannabis can interact with other medications, and that the quality and content of illicit cannabis can be highly variable and at times dangerous, it is important for physicians to discuss cannabis use with their patients. This can inform prescribing and allow them to educate patients on the dangers of medical cannabis and potential alternatives.

Targeting TRPV4 Channels for Cancer Pain Relief

Despite the unique and complex nature of cancer pain, the activation of different ion channels can be related to the initiation and maintenance of pain. The transient receptor potential vanilloid 4 (TRPV4) is a cation channel broadly expressed in sensory afferent neurons. This channel is activated by multiple stimuli to mediate pain perception associated with inflammatory and neuropathic pain. Here, we focused on summarizing the role of TRPV4 in cancer etiology and cancer-induced pain mechanisms. Many studies revealed that the administration of a TRPV4 antagonist and TRPV4 knockdown diminishes nociception in chemotherapy-induced peripheral neuropathy (CIPN). Although the evidence on TRPV4 channels' involvement in cancer pain is scarce, the expression of these receptors was reportedly enhanced in cancer-induced bone pain (CIBP), perineural, and orofacial cancer models following the inoculation of tumor cells to the bone marrow cavity, sciatic nerve, and tongue, respectively. Effective pain management is a continuous problem for patients diagnosed with cancer, and current guidelines fail to address a mechanism-based treatment. Therefore, examining new molecules with potential antinociceptive properties targeting TRPV4 modulation would be interesting. Identifying such agents could lead to the development of treatment strategies with improved pain-relieving effects and fewer adverse effects than the currently available analgesics.

Marijuana and Cannabidiol Use Prevalence and Symptom Management Among Patients with Cancer

Symptoms such as pain, nausea, and anxiety are common in individuals with cancer. Treatment of these issues is often challenging. Cannabis products may be helpful in reducing the severity of these symptoms. While some studies include data on the prevalence of cannabis use among patients with cancer, detailed data remain limited, and none have reported the prevalence of cannabidiol (CBD) use in this population. Adult patients with cancer attending eight clinics at a large, NCI-designated Comprehensive Cancer Center completed a detailed, cannabis-focused questionnaire between 2021 and 2022. Eligible participants were diagnosed with invasive cancer and treated in the past 12 months. Summary statistics were calculated to describe the sample regarding cannabis use. Approximately 15% (n = 142) of consented patients (n = 934) reported current cannabis use (defined as use within the past 12 months). Among which, 75% reported cannabis use in the past week. Among current cannabis users, 39% (n = 56; 6% overall) used CBD products. Current users reported using cannabis a median of 4.5 (interquartile range: 0.6–7.0) days/week, 2.0 (1.0–3.0) times per use/day, and for 3 years (0.8–30.0). Use patterns varied by route of administration. Patients reported moderate to high relief of symptoms with cannabis use. This study is the most detailed to date in terms of cannabis measurement and provides information about the current state of cannabis use in active cancer. Future studies should include complete assessments of cannabis product use, multiple recruitment sites, and diverse patient populations.

SIGNIFICANCE

Clinicians should be aware that patients are using cannabis products and perceive symptom relief with its use.

Cannabis for the Treatment of Fibromyalgia: A Systematic Review

Fibromyalgia is a common disease syndrome characterized by chronic pain and fatigue in conjunction with cognitive dysfunction such as memory difficulties. Patients currently face a difficult prognosis with limited treatment options and a diminished quality of life. Given its widespread use and potential efficacy in treating other types of pain, cannabis may prove to be an effective treatment for fibromyalgia. This review aims to examine and discuss current clinical evidence regarding the use of cannabis for the treatment of fibromyalgia. An electronic search was conducted on MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus using Medical Subject Heading (MeSH) terms on all literature published up to October 2022. A follow-up manual search included a complete verification of relevant studies. The results of four randomized controlled trials (RCTs) and five observational studies (a total of 564 patients) that investigated the effects of cannabis on fibromyalgia symptoms were included in this review. Of the RCTs, only one demonstrated that cannabinoids did not have a different effect than placebo on pain responses. Overall, this analysis shows low-quality evidence supporting short-term pain reduction in people with fibromyalgia treated with cannabinoid therapeutics. Although current evidence is limited, medical cannabis appears to be a safe alternative for treating fibromyalgia.

Women are Taking the Hit: Examining the Unique Consequences of Cannabis Use Across the Female Lifespan

Cannabis use has risen dramatically in recent years due to global decriminalization and a resurgence in the interest of potential therapeutic benefits. While emerging research is shaping our understanding of the benefits and harms of cannabis, there remains a paucity of data specifically focused on how cannabis affects the female population. The female experience of cannabis use is unique, both in the societal context and because of the biological ramifications. This is increasingly important given the rise in cannabis potency, as well as the implications this has for the prevalence of Cannabis Use Disorder (CUD). Therefore, this scoping review aims to discuss the prevalence of cannabis use and CUD in women throughout their lifespan and provide a balanced prospective on the positive and negative consequences of cannabis use. In doing so, this review will highlight the necessity for continued research that goes beyond sex differences.

Cannabinoids as a Potential Alternative to Opioids in the Management of Various Pain Subtypes: Benefits, Limitations, and Risks

INTRODUCTION

Pain is a global phenomenon encompassing many subtypes that include neuropathic, musculoskeletal, acute postoperative, cancer, and geriatric pain. Traditionally, opioids have been a mainstay pharmacological agent for managing many types of pain. However, opioids have been a subject of controversy with increased addiction, fatality rates, and cost burden on the US healthcare system. Cannabinoids have emerged as a potentially favorable alternative or adjunctive treatment for various types of acute and chronic pain. This narrative review seeks to describe the efficacy, risks, and benefits of cannabinoids as an adjunct or even potential replacement for opioids in the treatment of various subtypes of pain.

METHODS

In June of 2022, we performed a comprehensive search across multiple databases for English-language studies related to the use of cannabinoids in the treatment of various types pain: neuropathic pain, musculoskeletal pain, acute postoperative pain, cancer pain, and geriatric pain. Data from meta-analyses, systematic reviews, and randomized control trials (RCTs) were prioritized for reporting. We sought to focus our reported analysis on more recent literature as well as include older relevant studies with particularly notable findings.

RESULTS

There is conflicting evidence for the use of cannabinoids in the management of pain. While cannabinoids have shown efficacy in treating specific chronic pain subtypes such as neuropathic pain, fibromyalgia pain, and geriatric pain, they do not show as clear benefit in acute postoperative and the majority of musculoskeletal pain syndromes. Data trends towards cannabinoids having a positive effect in treating cancer pain, but results are not as conclusive. To date, there is a paucity of data comparing cannabinoids directly to opioids for pain relief. Overall, the side effects of cannabinoids appear to be relatively mild. However, there is still potential for addiction, altered brain development, psychiatric comorbidities, and drug-drug interactions.

CONCLUSION

Cannabinoids may be effective in specific subtypes of pain, but current evidence and guidelines do not yet support its use as the first-line treatment for any type of acute or chronic pain. Rather, it may be considered a good adjunct or alternative for patients who have failed more typical or conservative measures. Additional studies are needed with standardized forms of cannabinoids, route of delivery, and dosing for greater-powered analysis. Providers must weigh the individualized patient risks, benefits, and concurrent medication list in order to determine whether cannabinoids are appropriate for a patient's pain treatment plan.

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

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.

Increase in Cannabis Use Among Adults With Rheumatic Diseases: Results From a 2014-2019 United States Observational Study

OBJECTIVE

Despite advances in treatments and outcomes among patients with rheumatic diseases, there is an unmet need in pain management. Cannabis has emerged as a potential opioid-sparing alternative, with arthritic pain as a commonly cited reason for medicinal cannabis use. However, little is known, and we set out to understand patterns of cannabis use in a US-wide rheumatic disease population.

METHODS

The study included participants in FORWARD, The National Databank for Rheumatic Diseases. Participants were asked in 2014 and 2019 about their past and current cannabis use. Demographic characteristics, patient-reported outcomes, medications, comorbidities, and diagnoses were compared between cannabis users and non-users with t-tests, chi-square tests, logistic regression, and geographic assessment.

RESULTS

Among 11,006 respondents, cannabis use increased from 6.3% in 2014 to 18.4% in 2019, with the greatest prevalence of use in states where cannabis use was legalized. Most users (74% and 62% in 2014 and 2019, respectively) reported that cannabis was effective in the relief of arthritis symptoms. Cannabis users were more likely to be taking weak opioids (odds ratio 1.2 [95% confidence interval 1.0, 1.5], P = 0.03), to have a history of smoking tobacco (odds ratio 1.7 [95% confidence interval 1.5, 2.1], P < 0.001), and had worse measures on all assessed patient-reported outcomes.

CONCLUSION

Reported cannabis use in this cohort increased significantly between 2014 and 2019. Characteristics of users suggest that those who try cannabis are feeling worse symptomatically, and their pain management needs may not be adequately addressed by other therapies. The association between cannabis, opioids, and patient-reported outcomes highlight areas for future work.

Practical Considerations for the Use of Cannabis in Cancer Pain Management—What a Medical Oncologist Should Know

Pain is a highly debilitating emotional and sensory experience that significantly affects quality of life (QoL). Numerous chronic conditions, including cancer, are associated with chronic pain. In the setting of malignancy, pain can be a consequence of the tumor itself or of life-saving interventions, including surgery, chemotherapy, and radiotherapy. Despite significant pharmacological advances and awareness campaigns, pain remains undertreated in one-third of patients. To date, opioids have been the mainstay of cancer pain management. The problematic side effects and unsatisfactory pain relief of opioids have revived patients’ and physicians’ interest in finding new solutions, including cannabis and cannabinoids. The medical use of cannabis has been prohibited for decades, and it remains in Schedule 1 of the Misuse of Drugs Regulations. Currently, the legal context for its usage has become more permissive. Various preclinical and observational studies have aimed to prove that cannabinoids could be effective in cancer pain management. However, their clinical utility must be further supported by high-quality clinical trials.

Predictors of Pain Reduction Among Fibromyalgia Patients Using Medical Cannabis: A Long-Term Prospective Cohort Study

OBJECTIVE

Many patients with fibromyalgia (FM) report using cannabis as a strategy to improve pain. Given that pain often co-occurs with symptoms of anxiety and depression (i.e., negative affect) and sleep problems among patients with FM, improvements in these symptoms might indirectly contribute to reductions in pain intensity following cannabis use. The main objective of the study was to examine whether changes in pain intensity following initiation of medical cannabis among patients with FM could be attributed to concurrent changes (i.e., reductions) in negative affect and sleep problems.

METHODS

This was a 12-month prospective cohort study among patients with FM (n = 323) initiating medical cannabis under the care of physicians. Patients were assessed at baseline, and follow-up assessment visits occurred every 3 months after initiation of medical cannabis. Patients' levels of pain intensity, negative affect, and sleep problems were assessed across all visits.

RESULTS

Multilevel mediation analyses indicated that reductions in patients' levels of pain intensity were partly explained by concurrent reductions in sleep problems and negative affect (both P < 0.001). This remained significant even when accounting for patients' baseline characteristics or changes in medical cannabis directives over time (all P > 0.05).

CONCLUSION

Our findings provide preliminary insight into the potential mechanisms of action underlying pain reductions among patients with FM who are using medical cannabis. Given the high attrition rate (i.e., 75%) observed in the present study at 12 months, our findings cannot be generalized to all patients with FM who are using medical cannabis.

Long-term effectiveness and safety of medical cannabis administered through the metered-dose Syqe Inhaler

Supplemental Digital Content is Available in the Text.

Administration of low-dose medical cannabis through the metered-dose Syqe Inhaler demonstrates similar effectiveness on pain reduction and superior safety compared with other higher-dose administration routes.

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Molecular Alterations of the Endocannabinoid System in Psychiatric Disorders

The therapeutic benefits of the current medications for patients with psychiatric disorders contrast with a great variety of adverse effects. The endocannabinoid system (ECS) components have gained high interest as potential new targets for treating psychiatry diseases because of their neuromodulator role, which is essential to understanding the regulation of many brain functions. This article reviewed the molecular alterations in ECS occurring in different psychiatric conditions. The methods used to identify alterations in the ECS were also described. We used a translational approach. The animal models reproducing some behavioral and/or neurochemical aspects of psychiatric disorders and the molecular alterations in clinical studies in post-mortem brain tissue or peripheral tissues were analyzed. This article reviewed the most relevant ECS changes in prevalent psychiatric diseases such as mood disorders, schizophrenia, autism, attentional deficit, eating disorders (ED), and addiction. The review concludes that clinical research studies are urgently needed for two different purposes: (1) To identify alterations of the ECS components potentially useful as new biomarkers relating to a specific disease or condition, and (2) to design new therapeutic targets based on the specific alterations found to improve the pharmacological treatment in psychiatry.

Cannabis use, pain interference, and prescription opioid receipt among persons with HIV: a target trial emulation study

Concomitant with expanded legalization, cannabis is increasingly used to treat chronic pain among persons with HIV (PWH), despite equivocal benefit in research limited by small sample sizes and short duration of follow-up. To address these limitations, among a sample of PWH with pain interference enrolled in the Veterans Aging Cohort Study, we performed a target trial emulation study to compare the impact of four cannabis use strategies on pain interference. Among those receiving long-term opioid therapy (LTOT), we also explored impact of these strategies on ≥ 25% LTOT dose reduction. Among the analytic sample (N = 1284), the majority were men with a mean age of 50. Approximately 31% used cannabis and 12% received LTOT at baseline. Adjusting for demographic and clinical factors, cannabis use in any of 4 longitudinal patterns was not associated with resolved pain interference over 12- to 24-month follow-up. Among 153 participants receiving LTOT at baseline, cannabis use at both baseline and follow-up was negatively associated with LTOT dose reduction compared to no use at both baseline and follow-up. These findings support other observational studies finding no association between cannabis use and improved chronic pain or LTOT reduction among PWH.

Pain, cannabis use, and physical and mental health indicators among veterans and nonveterans: results from the National Epidemiologic Survey on Alcohol and Related Conditions-III

ABSTRACT

Chronic pain is associated with mental and physical health difficulties and is prevalent among veterans. Cannabis has been put forth as a treatment for chronic pain, and changes in laws, attitudes, and use patterns have occurred over the past 2 decades. Differences in prevalence of nonmedical cannabis use and cannabis use disorder (CUD) were examined across 2 groups: veterans or nonveterans and those reporting or not reporting recent pain. Data from the National Epidemiologic Survey on Alcohol and Related Conditions-III (2012-2013; n = 36,309) were analyzed using logistic regression. Prevalence differences (PDs) for 3 cannabis outcomes (1) past-year nonmedical cannabis use, (2) frequent (≥3 times a week) nonmedical use, and (3) DSM-5 CUD were estimated for those reporting recent moderate to severe pain (veterans or nonveterans) and veterans reporting or not reporting recent pain. Difference in differences was calculated to investigate PDs on outcomes associated with residence in a state with medical cannabis laws (MCLs). Associations between physical and mental health and cannabis variables were tested. The results indicated that the prevalence of recent pain was greater among veterans (PD = 7.25%, 95% confidence interval (CI) [4.90-9.60]). Among veterans, the prevalence of frequent cannabis use was greater among those with pain (PD = 1.92%, 98% CI [0.21-3.63]), and among veterans residing in a state with MCLs, the prevalence of CUD was greater among those reporting recent pain (PD = 3.88%, 98% CI [0.36-7.39]). Findings failed to support the hypothesis that cannabis use improves mental or physical health for veterans with pain. Providers treating veterans with pain in MCL states should monitor such patients closely for CUD.

Medical Cannabis and Utilization of Nonhospice Palliative Care Services: Complements and Alternatives at End of Life

Background and Objectives

There is a need to know more about cannabis use among terminally diagnosed older adults, specifically whether it operates as a complement or alternative to palliative care. The objective is to explore differences among the terminal illness population within the Illinois Medical Cannabis Program (IMCP) by their use of palliative care.

Research Design and Methods

The study uses primary, cross-sectional survey data from 708 terminally diagnosed patients, residing in Illinois, and enrolled in the IMCP. We compared the sample on palliative care utilization through logistic regression models, examined associations between palliative care and self-reported outcome improvements using ordinary least squares regressions, and explored differences in average pain levels using independent t-tests.

Results

115 of 708 terminally diagnosed IMCP participants were receiving palliative care. We find increased odds of palliative care utilization for cancer (odds ratio [OR] [SE] = 2.15 [0.53], p < .01), low psychological well-being (OR [SE] = 1.97 [0.58], p < .05), medical complexity (OR [SE] = 2.05 [0.70], p < .05), and prior military service (OR [SE] = 2.01 [0.68], p < .05). Palliative care utilization is positively associated with improvement ratings for pain (7.52 [3.41], p < .05) and ability to manage health outcomes (8.29 [3.61], p < .01). Concurrent use of cannabis and opioids is associated with higher pain levels at initiation of cannabis dosing (p < .05).

Discussion and Implications

Our results suggest that cannabis is largely an alternative to palliative care for terminal patients. For those in palliative care, it is a therapeutic complement used at higher levels of pain.

Cannabis use among cancer survivors in the United States: Analysis of a nationally representative sample

BACKGROUND

Research on cannabis use among those with a history of cancer is limited.

METHODS

Prevalence of past-year cannabis use among individuals with and without a cancer history and predictors of use within these 2 groups were determined using data from the Population Assessment of Tobacco and Health study, a nationally representative, longitudinal survey conducted in the United States (waves 1-4; 2013-2018). Discrete time survival analyses were used to estimate baseline (wave 1) predictors (physical health status, mental health status, pain, and demographic variables) on past-year engagement with cannabis within individuals who reported a cancer diagnosis at wave 1 (n = 1022) and individuals who reported never having cancer at any wave (n = 19,702).

RESULTS

At the most recent survey, 8% of cancer survivors reported past-year cannabis use, compared with 15% of those without a cancer history. Across 4 time points, an estimated 3.8% of cancer survivors engaged with cannabis, as compared to 6.5% of those without a cancer history. Across both groups, older age and having health insurance were associated with lower likelihood of engaging in cannabis use, whereas greater levels of pain were associated with higher likelihood of engaging in cannabis use. Among those without a cancer history, being female, White, and having better mental health status were associated with lower likelihood of engaging in cannabis use.

CONCLUSIONS

Although cannabis use prevalence is lower among cancer survivors, the reasons for use are not markedly different from those without a cancer history. Continued monitoring of use, reasons for use, and harms or benefits is warranted.

LAY SUMMARY

Results from this study, which uses data from the Population Assessment of Tobacco and Health Study, indicate that cannabis use is generally increasing across cancer survivors and those without a history of cancer. Cancer survivors are using cannabis at slightly lower rates than those without a history of cancer. Factors related to pain seem to be more prevalent in cancer populations relative to the general population, and could be contributing to cannabis use within cancer survivor populations.

Physicians' experiences, attitudes, and beliefs towards medical cannabis: a systematic literature review

Background

An increasing number of countries legalise the use of medical cannabis or allow it for a narrow range of medical conditions. Physicians, and often the patients’ general practitioner, play a major role in implementing this policy. Many of them, however, perceive a lack of evidence-based knowledge and are not confident with providing patients with medical cannabis. The objectives of this review are to synthesise findings about hospital physicians’ and GPs’ experiences, attitudes, and beliefs towards the use of medical cannabis with the purpose of identifying barriers and facilitators towards providing it to their patients.

Methods

Peer-reviewed articles addressing hospital physicians’ and GPs’ experiences, attitudes, and beliefs towards the use of medical cannabis were searched systematically in PubMed, Scopus, EMBASE, and the Cochrane Library.

Results

Twenty-one articles were included from five different countries in which the medical cannabis laws varied. The studied physicians experienced frequent inquiries about medical cannabis from their patients (49–95%), and between 10 and 95% of the physicians were willing to prescribe and/or provide it to the patients, depending on setting, specialty and experience among the physicians. This review found that physicians experienced in prescribing medical cannabis were more convinced of its benefits and less worried about adverse effects than non-experienced physicians. However, physicians specialized in addiction treatment and certain relevant indication areas seemed more sceptical compared to physicians in general. Nevertheless, physicians generally experienced a lack of knowledge of clinical effects including both beneficial and adverse effects.

Conclusion

This review indicates that GPs and hospital physicians from various specialties frequently experience patient demands for medical cannabis and to some degree show openness to using it, although there was a wide gap between studies in terms of willingness to provide. Hospital physicians and GPs’ experienced in prescribing are more convinced of effects and less worried of adverse effects. However, most physicians experience a lack of knowledge of beneficial effects, adverse effects and of how to advise patients, which may comprise barriers towards prescribing. More research, including larger studies with cohort designs and qualitative studies, is needed to further examine facilitators and barriers to physicians’ prescribing practices.

A qualitative study of VHA clinicians' knowledge and perspectives on cannabis for medical purposes

BACKGROUND

The legalization of cannabis is expanding across the USA, and its use has increased significantly, including among Veterans. Although the Veterans Health Administration (VHA) abides by the classification of cannabis as a Schedule I substance, it recently recommended that clinicians discuss cannabis with their patients. Little is known about VHA clinicians' perspectives on and knowledge of cannabis.

OBJECTIVE

We sought to better understand clinicians' attitudes, beliefs, knowledge and communication with patients regarding cannabis.

METHODS

We conducted semi-structured phone interviews with 14 VHA clinicians. Interviews were audio-recorded, transcribed verbatim and analysed using qualitative thematic analysis.

RESULTS

VA clinicians described ambivalence towards cannabis for therapeutic purposes and identified several factors that inhibit conversations about cannabis use with their patients including discomfort with the lack of product standardization; lack of research examining the effectiveness and risks of cannabis use; unfamiliarity with pharmacology, formulations, and dosing of cannabis; and uncertainty regarding VHA policy. Clinicians had differing views on cannabis in the context of the opioid crisis.

CONCLUSIONS

VA clinicians face challenges in navigating the topic of medical cannabis. Educational materials about cannabis products, dose and harms would be helpful to clinicians.

Cannabis and End-of-Life Care: A Snapshot of Hospice Planning and Experiences Among Illinois Medical Cannabis Patients With A Terminal Diagnosis

INTRODUCTION

Between 2013 and 2019, Illinois limited cannabis access to certified patients enrolled in the Illinois Medical Cannabis Program (IMCP). In 2016, the state instituted a fast-track pathway for terminal patients. The benefits of medicinal cannabis (MC) have clear implications for patients near end-of-life (EOL). However, little is known about how terminal patients engage medical cannabis relative to supportive care.

METHODS

Anonymous cross-sectional survey data were collected from 342 terminal patients who were already enrolled in (n = 19) or planning to enroll (n = 323) in hospice for EOL care. Logistic regression models compare patients in the sample on hospice planning vs. hospice enrollment, use of palliative care vs. hospice care, and use standard care vs non-hospice palliative care.

RESULTS

In our sample, cancer patients (OR = 0.21 (0.11), p < .01), and those who used the fast-track application into the IMCP (OR = 0.11 (0.06), p < .001) were less likely to be enrolled in hospice. Compared to patients in palliative care, hospice patients were less likely to report cancer as their qualifying condition (OR = 0.16 (0.11), p < .01), or entered the IMCP via the fast-track (OR = 0.23 (0.15), p < .05).

DISCUSSION

Given low hospice enrollment in a fairly large EOL sample, cannabis use may operate as an alternative to supportive forms of care like hospice and palliation. Clinicians should initiate conversations about cannabis use with their patients while also engaging EOL Care planning discussions as an essential part of the general care plan.

Specific phytocannabinoid compositions are associated with analgesic response and adverse effects in chronic pain patients treated with medical cannabis

Medical cannabis (MC) treatment for chronic pain is increasing, but evidence regarding short- and long-term efficacy and associated adverse effects (AEs) of the different cannabis plant components is limited. Most reports focus on two phytocannabinoids, (-)-Δ⁹-trans-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD). This study, aimed to identify patterns of phytocannabinoid compositions associated with MC treatment response and with related AEs. Participants in this multicenter prospective cohort were patients with chronic non-cancer pain that were prescribed MC by physicians. Data was collected before MC treatment, at one month (short-term) and at 12 months (long-term). Simultaneously, liquid chromatography mass spectrometry identification and quantification of phytocannabinoids from the cultivars were performed. The monthly dose of each phytocannabinoid for each patient was z-scaled and clustered into ten groups to assess the difference in analgesic treatment response (≥30%/50% pain intensity reduction) and AEs rates. We identified ten clusters that had similar analgesic treatment response rates. However, there were significant differences in AEs rates both at short- and long-term. We identified specific phytocannabinoid compositions that were associated with overall AEs rates (5% compared to 53% at short-term and 44% at long-term) and with specific AEs rates such as MC related central nervous system, gastrointestinal and psychological AEs. To conclude, Evaluating only Δ9-THC or CBD is insufficient to find associations with MC related AEs. Therefore, comprehensive profiling of phytocannabinoids is needed to discover associations to related AEs and help physicians prescribe safer cannabis with less AEs while still relieving pain.

Can Medical Cannabis Therapies be Cost-Effective in the Non-Surgical Management of Chronic Knee Pain?

Introduction:

Chronic knee pain is a common musculoskeletal condition, which usually leads to decreased quality of life and a substantial financial burden. Various non-surgical treatments have been developed to relieve pain, restore function and delay surgical intervention. Research on the benefits of medical cannabis (MC) is emerging supporting its use for chronic pain conditions. The purpose of this study was to evaluate the cost-effectiveness of MC compared to current non-surgical therapies for chronic knee pain conditions.

Methods:

We conducted a cost-utility analysis from a Canadian, single payer perspective and compared various MC therapies (oils, soft gels and dried flowers at different daily doses) to bracing, glucosamine, pharmaceutical-grade chondroitin oral non-steroidal anti-inflammatory drugs (NSAIDs), and opioids. We estimated the quality-adjusted life years (QALYs) gained with each treatment over 1 year and calculated incremental cost-utility ratios (ICURs) using both the mean and median estimates for costs and utilities gained across the range of reported values. The final ICURs were compared to willingness-to-pay (WTP) thresholds of $66 714, $133 428 and $200 141 Canadian dollars (CAD) per QALY gained.

Results:

Regardless of the estimates used (mean or median), both MC oils and soft gels at both the minimal and maximal recommended daily doses were cost-effective compared to all current knee pain therapies at the lowest WTP threshold. Dried flowers were only cost-effective up to a certain dosage (0.75 and 1 g/day based on mean and median estimates, respectively), but all dosages were cost-effective when the WTP was increased to $133 428/QALY gained.

Conclusion:

Our study showed that MC may be a cost-effective strategy in the management of chronic knee pain; however, the evidence on the medical use of cannabis is limited and predominantly low-quality. Additional trials on MC are definitely needed, specifically in patients with chronic knee pain.

Review of the Current State of Urine Drug Testing in Chronic Pain: Still Effective as a Clinical Tool and Curbing Abuse, or an Arcane Test?

PURPOSE OF REVIEW

Therapeutic use, misuse, abuse, and diversion of controlled substances in managing chronic non-cancer pain remain a major concern for physicians, the government, payers, and patients. The challenge remains finding effective diagnostic tools that can be clinically validated to eliminate or substantially reduce the abuse of controlled prescription drugs, while still assuring the proper treatment of those patients in pain. Urine drug testing still remains an important means of adherence monitoring, but questions arise as to its relevance and effectiveness. This review examines the role of UDT, determines its utility in current clinical practice, and investigates its relevance in current chronic pain management.

RECENT FINDINGS

A review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Literature was searched from year 2000 to present examining the relevance and role of UDT in monitoring chronic opioid therapy along with reliability and accuracy, appropriate use, overuse, misuse, and abuse. There are only a limited number of reviews and investigations on UDT, despite the fact that clinicians who prescribe controlled medications for chronic states commonly are expected to utilize UDT. Therefore, despite highly prevalent use, there is a limited publication base from which to draw in this present study. Regardless of experience or training background, physicians and healthcare providers can much more adequately assess opioid therapy with the aid of UDT, which often requires confirmatory testing by a laboratory for clinical and therapeutic prescribing decisions. It has become a strongly recommended aspect of pain care with controlled substances locally, regionally, and nationally. Incorporating UDT for all patients in whom chronic opioid therapy is undertaken is consistent with state and national guidelines and best practice strategies. Practice standards vary as to the frequency of UDT locally, regionally, and nationally, however.

State Medical Cannabis Laws Associated With Reduction in Opioid Prescriptions by Orthopaedic Surgeons in Medicare Part D Cohort

INTRODUCTION

Opioid prescriptions and abuse remain a significant national concern. Cannabinoids offer a potentially attractive nonopioid analgesic option for orthopaedic patients, and 32 US states have passed medical cannabis laws (MCLs), legalizing patient access to cannabinoids. We examine the association between implementation of state cannabis laws and prescribing patterns for opioids by orthopaedic surgeons in Medicare Part D patients between 2013 and 2017.

METHODS

Using the Medicare Part D Prescription Drug Event database, we measured annual aggregate daily doses of all opioid medications (excluding buprenorphine) prescribed by orthopaedic surgeons in each US state (and DC), in addition to total daily doses of opioid medications by generic name (hydrocodone, oxycodone, fentanyl, morphine, methadone, and "other opioids"). We used adjusted linear regression models to examine associations between state-specific cannabis regulations (state MCL, MCL type-dispensary or home cultivation, and recreational cannabis legalization) and annual total daily doses of opioid medications (all opioids and opioid types, separately).

RESULTS

State MCLs were associated with a statistically significant reduction in aggregate opioid prescribing of 144,000 daily doses (19.7% reduction) annually (95% confidence interval [CI], -0.535 to -0.024 million; P < 0.01). States with MCLs allowing access to in-state dispensaries had a statistically significant reduction in total opioid prescriptions of 96,000 daily doses (13.1%) annually (95% CI, -0.165 to -0.026 million; P < 0.01). Specifically, MCLs were associated with a statistically significant reduction of 72,000 daily doses of hydrocodone annually (95% CI, -0.164 to -0.019 million; P < 0.01). No significant association between recreational marijuana legalization and opioid prescribing was found.

CONCLUSION

Orthopaedic surgeons are among the highest prescribers of opioids, highlighting the importance of providing nonopioid analgesic alternatives in efforts to reduce opioid use in the patient cohort. This study is the first to examine the association between implementation of state cannabis laws and prescribing patterns for opioids by orthopaedic surgeons in Medicare Part D patients.

LEVEL OF EVIDENCE

Population-based ecological study.

Communication between healthcare providers and medical cannabis patients regarding referral and medication substitution

BACKGROUND

People report using cannabis as a substitute for prescription medications but may be doing so without the knowledge of their primary health care providers (PCPs). This lack of integration creates serious concerns, e.g., using cannabis to treat medical conditions that have established treatment options.

METHODS

We conducted an anonymous, cross-sectional online survey among patrons of a medical cannabis dispensary in Michigan (n = 275) to examine aspects of their relationship with their PCP and their perceptions of PCP knowledge related to cannabis.

RESULTS

Overall, 64% of participants initiated medical cannabis use based on their own experiences vs. 24% citing advice from their PCP. Although 80% reported that their PCP knew they currently used medical cannabis, 41% reported that their PCP had not always known. Only 14% obtained their medical cannabis authorization from their PCP. Only 18% of participants rated their PCP's knowledge about medical cannabis as very good or excellent and only 21% were very or completely confident in their PCP's ability to integrate medical cannabis into their treatment. Although 86% had substituted cannabis for pharmaceutical medications, 69% (n = 134) of those who substituted reported some gap in their PCP's knowledge of their substitution, and 44% (n = 86) reported that their PCP was currently unaware of their substitution.

CONCLUSIONS

Patients frequently substitute cannabis for prescription drugs, often without PCP knowledge. Although most participants disclosed cannabis use to their PCP, their perceptions of PCP knowledge ranged widely and many obtained medical cannabis licensure from an outside physician. Our results highlight the need for standardized physician education around appropriate medical cannabis use.

Short-Term Medical Cannabis Treatment Regimens Produced Beneficial Effects among Palliative Cancer Patients

In the last decade the use of medical cannabis (MC) for palliative cancer treatment has risen. However, the choice between products is arbitrary and most patients are using Tetrahydrocannabinol (THC)-dominant cannabis products. In this study, we aimed to assess the short-term outcomes of MC treatment prescribed by oncologists in relation to the type of cannabis they receive. A comparative analysis was used to assess the differences in treatment effectiveness and safety between THC-dominant (n = 56, 52%), cannabidiol (CBD)-dominant (n = 19, 18%), and mixed (n = 33, 30%) MC treatments. Oncology patients (n = 108) reported on multiple symptoms in baseline questionnaires, initiated MC treatment, and completed a one-month follow-up. Most parameters improved significantly from baseline, including pain intensity, affective and sensory pain, sleep quality and duration, cancer distress, and both physical and psychological symptom burden. There was no significant difference between the three MC treatments in the MC-related safety profile. Generally, there were no differences between the three MC treatments in pain intensity and in most secondary outcomes. Unexpectedly, CBD-dominant oil treatments were similar to THC-dominant treatments in their beneficial effects for most secondary outcomes. THC-dominant treatments showed significant superiority in their beneficial effect only in sleep duration compared to CBD-dominant treatments. This work provides evidence that, though patients usually consume THC-dominant products, caregivers should also consider CBD-dominant products as a useful treatment for cancer-related symptoms.

Motivations and expectations for using cannabis products to treat pain in humans and dogs: a mixed methods study

BACKGROUND

Social media and academic literature suggest that more people are using cannabis to treat their own or their dog's chronic pain. This study identifies the reasons people use cannabis products to treat their own pain or their dog's pain and explores whether these products have fulfilled their expectations.

METHODS

An anonymous, online survey was used to collect quantitative and qualitative self-report data on respondents' perceptions, motivations and expectations about their or their dog's chronic pain and cannabis use. The analyses are based on U.S. adults who reported using cannabis products to treat their own (N = 313) or their dog's (N = 204) chronic pain. Quantitative responses from the two groups were compared using Chi-Square tests and qualitative data were analyzed using a thematic analysis.

RESULTS

Human patients and dog owners reported similar motivations for using cannabis products to treat chronic pain, with the more popular reasons being that cannabis products are natural, are preferred over conventional medication, are believed to be the best treatment or good treatment option for pain. Similar proportions of human patients and dog owners reported that the use of cannabis products fulfilled their expectations (86% vs. 82% respectively, χ2 (1, 200) = .59, p = .32). The qualitative data revealed that their expectations were met by reducing pain, increasing relaxation, and improving sleep, coping, functionality and overall well being. Additionally, the qualitative data suggests that cannabis products offer a return to normalcy and a restored sense of self to human and dog patients.

CONCLUSIONS

The results suggest that people choose cannabis products because they are natural and a possible solution to managing chronic pain when conventional medicines have not been effective. Most people report that their expectations regarding pain management are fulfilled by these products. More accurate assessments are vital, however, for understanding both the objective biomedical and subjective socioemotional benefits of cannabis products for effective pain management for human and dog patients. In addition, objective factual information regarding cannabis products for effective pain management in humans and dogs is needed. It is recommended that both physicians and veterinarians work towards feeling more comfortable proactively broaching the subject of cannabis use with additional training and education.

Psychosocial and Clinical Risk Factors Associated with Substance Use in Observational Cohort of Patients with Sickle Cell Disease

BACKGROUND

Patients with sickle cell disease (SCD) experience high rates of chronic pain, and have a high burden of mental health comorbidities shown to negatively influence health. There is limited research on substance use among individuals with SCD. Objective: The aim of this study is to measure the prevalence of substance use in patients with SCD and determine whether psychosocial or clinical risk factors are associated with substance use. Methods: This study was conducted as part of an observational study of patients with SCD at two academic medical centers. We asked participants (ages 15 and older) about the lifetime use of heroin, cocaine, amphetamines, and marijuana/cannabis. We measured stigma, depression, urban life stress, pain catastrophizing, and asked about a brief pain inventory. Results: Of 258 participants, 24.9% (n = 71) reported substance use. Marijuana was the most common substance used (22.5%; n = 65). The mean depressive score met criteria for positive screen amongst individuals who reported a history of substance use (mean 10.7(5.76)). Adjusting for age, sex, yearly family income, and education level, odds of substance use increased with higher levels of internalized stigma (aOR: 1.38; 95% CI: 1.07, 1.77; p = 0.012); higher urban life stress scores (aOR 1.06; 95% CI: 1.01, 1.12; p = 0.017) and higher pain catastrophizing scores (aOR: 1.03; 95% CI: 1.01, 1.06; p = 0.008). Conclusions: Among individuals with SCD who endorse substance use, there was markedly more stress and distress with higher rates of depression and poorer quality of life. Interventions focusing on improving distress tolerance and coping to not only pain, but also social stressors, might reduce substance use.

High Doses of Δ9-Tetrahydrocannabinol Might Impair Irinotecan Chemotherapy: A Review of Potentially Harmful Interactions

This review proposes the hypothesis that the effectiveness of irinotecan chemotherapy might be impaired by high doses of concomitantly administered Δ⁹-tetrahydrocannabinol (THC). The most important features shared by irinotecan and THC, which might represent sources of potentially harmful interactions are: first-pass hepatic metabolism mediated by cytochrome P450 (CYP) enzyme CYP3A4; glucuronidation mediated by uridine diphosphate glycosyltransferase (UGT) enzymes, isoforms 1A1 and 1A9; transport of parent compounds and their metabolites via canalicular ATP-binding cassette (ABC) transporters ABCB1 and ABCG2; enterohepatic recirculation of both parent compounds, which leads to an extended duration of their pharmacological effects; possible competition for binding to albumin; butyrylcholinesterase (BChE) inhibition by THC, which might impair the conversion of parent irinotecan into the SN-38 metabolite; mutual effects on mitochondrial dysfunction and induction of oxidative stress; potentiation of hepatotoxicity; potentiation of genotoxicity and cytogenetic effects leading to genome instability; possible neurotoxicity; and effects on bilirubin. The controversies associated with the use of highly concentrated THC preparations with irinotecan chemotherapy are also discussed. Despite all of the limitations, the body of evidence provided here could be considered relevant for human-risk assessments and calls for concern in cases when irinotecan chemotherapy is accompanied by preparations rich in THC.

Clinical Data for the Use of Cannabis-Based Treatments: A Comprehensive Review of the Literature

Objective:

To compile and synthesize the available literature describing medical cannabis use across various disease states.

Data Sources:

PubMed, EBSCO, and Google Scholar searches were conducted using MeSH and/or keywords.

Study Selection and Data Extraction:

Studies were included if they described the use of cannabis-based products and medications in the treatment of a predefined list of disease states in humans and were published in English. The extraction period had no historical limit and spanned through April 2019.

Data Synthesis:

Evidence was compiled and summarized for the following medical conditions: Alzheimer disease, amyotrophic lateral sclerosis, autism, cancer and cancer-associated adverse effects, seizure disorders, human immunodeficiency virus, inflammatory bowel disease, multiple sclerosis (MS), nausea, pain, posttraumatic stress disorder, and hospice care.

Relevance to Patient Care and Clinical Practice:

Based on identified data, the most robust evidence suggests that medical cannabis may be effective in the treatment of chemotherapy-induced nausea and vomiting, seizure disorders, MS-related spasticity, and pain (excluding diabetic neuropathy). Overall, the evidence is inconsistent and generally limited by poor quality. The large variation in cannabis-based products evaluated in studies limits the ability to make direct comparisons. Regardless of the product, a gradual dose titration was utilized in most studies. Cannabis-based therapies were typically well tolerated, with the most common adverse effects being dizziness, somnolence, dry mouth, nausea, and euphoria.

Conclusions:

As more states authorize medical cannabis use, there is an increasing need for high-quality clinical evidence describing its efficacy and safety. This review is intended to serve as a reference for clinicians, so that the risks and realistic benefits of medical cannabis are better understood.

Cannabinoids in the descending pain modulatory circuit: Role in inflammation

The legalization of cannabis in some states has intensified interest in the potential for cannabis and its constituents to lead to novel therapeutics for pain. Our understanding of the cellular mechanisms underlying cannabinoid actions in the brain have lagged behind opioids; however, the current opioid epidemic has also increased attention on the use of cannabinoids as alternatives to opioids for pain, especially chronic pain that requires long-term use. Endogenous cannabinoids are lipid signaling molecules that have complex roles in modulating neuronal function throughout the brain. In this review, we discuss cannabinoid functions in the descending pain modulatory pathway, a brain circuit that integrates cognitive and emotional processing of pain to modulate incoming sensory inputs. In addition, we highlight areas where further studies are necessary to understand cannabinoid regulation of descending pain modulation.

Clinician Response to Aberrant Urine Drug Test Results of Patients Prescribed Opioid Therapy for Chronic Pain

OBJECTIVE

Urine drug testing (UDT) is recommended for patients who are prescribed opioid medications, but little is known about the various strategies clinicians use to respond to aberrant UDT results. We sought to examine changes in opioid prescribing and implementation of other risk reduction activities following an aberrant UDT.

METHODS

In a national cohort of Veterans Affairs patients with new initiations of opioid therapy through 2013, we identified a random sample of 100 patients who had aberrant positive UDTs (results positive for nonprescribed/illicit substance), 100 who had aberrant negative UDTs (results negative for prescribed opioid), and 100 who had expected UDT results. We examined medical record data for opioid prescribing changes and risk reduction strategies in the 12 months following UDT.

RESULTS

Following an aberrant UDT, 17.5% of clinicians documented planning to discontinue or change the opioid dose and 52.5% initiated another strategy to reduce opioid-related risk. In multivariate analyses, variables associated with a planned change in opioid prescription status were having an aberrant positive UDT (odds ratio [OR], 30.77; 95% confidence interval [CI], 5.92-160.10) and higher prescription opioid dose (OR, 1.01; 95% CI, 1.01-1.02). The only variable associated with implementation of other risk reduction activities was having an aberrant positive UDT (OR, 0.29; 95% CI, 0.16-0.55).

DISCUSSION

The majority of clinicians enacted some type of opioid prescribing or other change to reduce risk following an aberrant UDT, and the action depended on whether the result was an aberrant positive or aberrant negative UDT. Experimental studies are needed to develop and test strategies for managing aberrant UDT results.

Myrcene and terpene regulation of TRPV1

Nociceptive Transient Receptor Potential channels such as TRPV1 are targets for treating pain. Both antagonism and agonism of TRP channels can promote analgesia, through inactivation and chronic desensitization. Since plant-derived mixtures of cannabinoids and the Cannabis component myrcene have been suggested as pain therapeutics, we screened terpenes found in Cannabis for activity at TRPV1. We used inducible expression of TRPV1 to examine TRPV1-dependency of terpene-induced calcium flux responses. Terpenes contribute differentially to calcium fluxes via TRPV1 induced by Cannabis-mimetic cannabinoid/terpenoid mixtures. Myrcene dominates the TRPV1-mediated calcium responses seen with terpenoid mixtures. Myrcene-induced calcium influx is inhibited by the TRPV1 inhibitor capsazepine and Myrcene elicits TRPV1 currents in the whole-cell patch-clamp configuration. TRPV1 currents are highly sensitive to internal calcium. When Myrcene currents are evoked, they are distinct from capsaicin responses on the basis of Imax and their lack of shift to a pore-dilated state. Myrcene pre-application and residency at TRPV1 appears to negatively impact subsequent responses to TRPV1 ligands such as Cannabidiol, indicating allosteric modulation and possible competition by Myrcene. Molecular docking studies suggest a non-covalent interaction site for Myrcene in TRPV1 and identifies key residues that form partially overlapping Myrcene and Cannabidiol binding sites. We identify several non-Cannabis plant-derived sources of Myrcene and other compounds targeting nociceptive TRPs using a data mining approach focused on analgesics suggested by non-Western Traditional Medical Systems. These data establish TRPV1 as a target of Myrcene and suggest the therapeutic potential of analgesic formulations containing Myrcene.

c-Jun N terminal kinase signaling pathways mediate cannabinoid tolerance in an agonist-specific manner

Tolerance to the antinociceptive effects of cannabinoids represents a significant limitation to their clinical use in managing chronic pain. Tolerance likely results from desensitization and down-regulation of the cannabinoid type 1 receptor (CB₁R), with CB₁R desensitization occurring via phosphorylation of CB₁Rs by a G protein-coupled receptor kinase and subsequent association with an arrestin protein. Previous studies have shown that (1) desensitization-resistant S426A/S430A mice exhibit a modest delay in tolerance for Δ⁹-THC and (-)-CP55,940 but a more pronounced disruption in tolerance for WIN 55,212-2 and (2) that c-Jun N-terminal kinase (JNK) signaling may selectively mediate antinociceptive tolerance to morphine compared to other opioid analgesics. In the current study, we found that pretreatment with the JNK inhibitor SP600125 (3 mg/kg) attenuates tolerance to the antinociceptive in the formalin test and to the anti-allodynic effects of Δ⁹-THC (6 mg/kg) in cisplatin-evoked neuropathic pain using wild-type mice. We also find that SP600125 causes an especially robust reduction in tolerance to the antinociceptive effects of Δ⁹-THC (30 mg/kg), but not WIN 55,212-2 (10 mg/kg) in the tail-flick assay using S426A/S430A mice. Interestingly, SP600125 pretreatment accelerated tolerance to the antinociceptive and anti-allodynic effects of (-)-CP55,940 (0.3 mg/kg) in mice with acute and neuropathic pain. These results demonstrate that inhibition of JNK signaling pathways delay tolerance to Δ⁹-THC, but not to CP55,940 or WIN55,212-2, demonstrating that the mechanisms of cannabinoid tolerance are agonist-specific.

High-Frequency Medical Cannabis Use Is Associated With Worse Pain Among Individuals With Chronic Pain

Cannabis is widely used for chronic pain. However, there is some evidence of an inverse dose-response relationship between cannabis effects and pain relief that may negatively affect analgesic outcomes. In this cross-sectional survey, we examined whether daily cannabis use frequency was associated with pain severity and interference, quality of life measures relevant to pain (eg, anxiety and depressive symptoms), and cannabis use preferences (administration routes and cannabinoid ratio). Our analysis included 989 adults who used cannabis every day for chronic pain. Participant use was designated as light, moderate, and heavy (1-2, 3-4, and 5 or more cannabis uses per day, respectively). The sample was also subgrouped by self-reported medical-only use (designated MED, n = 531, 54%) versus medical use concomitant with a past-year history of recreational use (designated MEDREC, n = 458, 46%). In the whole sample, increased frequency of use was significantly associated with worse pain intensity and interference, and worse negative affect, although high-frequency users also reported improved positive affect. Subgroup analyses showed that these effects were driven by MED participants. Heavy MED participant consumption patterns showed greater preference for smoking, vaporizing, and high tetrahydrocannabinol products. In contrast, light MED participants had greater preference for tinctures and high cannabidiol products. Selection bias, our focus on chronic pain, and our cross-sectional design likely limit the generalizability of our results. Our findings suggest that lower daily cannabis use frequency is associated with better clinical profile as well as lower risk cannabis use behaviors among MED participants. Future longitudinal studies are needed to examine how high frequency of cannabis use interacts with potential therapeutic benefits. PERSPECTIVE: Our findings suggest that lower daily cannabis use frequency is associated with better clinical profile as well as safer use behaviors (eg, preference for cannabidiol and noninhalation administration routes). These trends highlight the need for developing cannabis use guidelines for clinicians to better protect patients using cannabis.

State marijuana laws and opioid overdose mortality

BACKGROUND

The opioid epidemic in the United States is a national public health crisis. In recent years, marijuana legalization has been increasingly adopted by state governments as a policy intervention to control the opioid epidemic under the premise that marijuana and opioids are substitutive substances. The purpose of this systematic review is to synthesize the empirical evidence regarding the impact of state marijuana laws on opioid overdose mortality and other opioid-related health outcomes.

METHOD

A comprehensive search of the research literature in 18 bibliographic databases returned 6640 records, with 5601 abstracts reviewed, 29 full text articles screened for eligibility, and 16 eligible studies included in the systematic review. Comprehensive Meta-Analysis software was used to generate summary estimates, forest plots, funnel plots, and heterogeneity statistics.

RESULTS

Of the 16 eligible studies, 4 assessed the association of state marijuana law status with opioid overdose mortality, 7 with prescription opioids dispensed, and the remaining with nonmedical use and opioid-related hospitalizations. Random effects modeling based on pooled data revealed that legalizing marijuana for medical use was associated with a statistically non-significant 8% reduction in opioid overdose mortality (95% confidence interval: - 0.21 to 0.04; p = 0.201) and a 7% reduction in prescription opioids dispensed (95% confidence interval: - 0.13 to - 0.01; p = 0.017). Legalizing marijuana for recreational use was associated with an additional 7% reduction in opioid overdose mortality in Colorado and 6% reduction in opioid prescriptions among fee-for-service Medicaid and managed care enrollees.

CONCLUSIONS

Legalizing marijuana might contribute to a modest reduction in opioid prescriptions. Evidence about the effect of marijuana legalization on opioid overdose mortality is inconsistent and inconclusive. If any, the effectiveness of state marijuana laws in reducing opioid overdose mortality appears to be rather small and limited to states with operational marijuana dispensaries. It remains unclear whether the presumed benefit of legalizing marijuana in reducing opioid-related harms outweighs the policy's externalities, such as its impact on mental health and traffic safety.

Is there a relationship between cannabis use problems, emotion dysregulation, and mental health problems among adults with chronic pain?

Cannabis is often used to manage pain among persons who suffer from chronic pain. Yet, despite much literature suggesting cannabis use problems are associated with mental health problems, little work has examined mechanisms of this relationship among a chronic pain population. Chronic pain is also associated with emotion dysregulation. Individuals with chronic pain who experience cannabis use problems may have less capacity to regulate negative emotions, which could relate to greater anxiety, depression, and suicidal ideation. Thus, the current study explored whether emotion dysregulation explained, in part, the relation between cannabis use problems and anxiety, depression, and suicidal ideation among adults with chronic pain. Participants were 431 opioid-using adults with current moderate to severe chronic pain, 176 were current cannabis users, of which 30.20% reported cannabis use problems. Results indicated a significant indirect relationship between cannabis use problems and anxiety [95% CI (.03, .05)], depression [95% CI (.03, .06)], and suicidal ideation [95% CI (.01, .01)] via emotion dysregulation. Tests of specificity suggested potential for a bi-directional effect for suicidal ideation (p < .001). Initial findings suggest that emotion dysregulation may be an important mechanism in the relationship between cannabis use problems and mental health among adults with chronic pain.

Effects of cannabinoid administration for pain: A meta-analysis and meta-regression

Chronic pain states have resulted in an overreliance on opioid pain relievers, which can carry significant risks when used long term. As such, alternative pain treatments are increasingly desired. Although emerging research suggests that cannabinoids have therapeutic potential regarding pain, results from studies across pain populations have been inconsistent. To provide meta-analytic clarification regarding cannabis's impact on subjective pain, we identified studies that assessed drug-induced pain modulations under cannabinoid and corresponding placebo conditions. A literature search yielded 25 peer-reviewed records that underwent data extraction. Baseline and end-point data were used to compute standardized effect size estimates (Cohen's d) across cannabinoid administrations (k = 39) and placebo administrations (k = 26). Standardized effects were inverse-variance weighted and pooled across studies for meta-analytic comparison. Results revealed that cannabinoid administration produced a medium-to-large effect across included studies, Cohen's d = -0.58, 95% confidence interval (CI) [-0.74, -0.43], while placebo administration produced a small-to-medium effect, Cohen's d = -0.39, 95% CI [-0.52, -0.26]. Meta-regression revealed that cannabinoids, β = -0.43, 95% CI [-0.62, -0.24], p < .05, synthetic cannabinoids, β = -0.39, 95% CI [-0.65, -0.14], p < .05, and sample size, β = 0.01, 95% CI [0.00, 0.01], p < .05, were associated with marked pain reduction. These outcomes suggest that cannabinoid-based pharmacotherapies may serve as effective replacement/adjunctive options regarding pain, however, additional research is warranted. Additionally, given demonstrated neurocognitive side effects associated with some constituent cannabinoids (i.e., THC), subsequent work may consider developing novel therapeutic agents that capitalize on cannabis's analgesic properties without producing adverse effects. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Cannabis Use Motivations among Adults Prescribed Opioids for Pain versus Opioid Addiction

BACKGROUND

Cannabis has been linked to reduced opioid use, although reasons for cannabis use among adults prescribed opioids are unclear.

AIMS

The purpose of this study was to determine whether motivations for cannabis use differ between adults prescribed opioids for persistent pain versus those receiving opioids as medication-assisted treatment for opioid use disorder.

DESIGN

A cross-sectional survey design was used.

PARTICIPANTS

Adults prescribed opioids for persistent pain (n = 104) or opioid use disorder (n = 139) were recruited from outpatient settings.

METHODS

Data were collected on surveys asking about cannabis use and compared the two populations. A series of regression models examined population characteristics and cannabis use motivations using validated measures of the Marijuana Motives Measure scale.

RESULTS

More than half the sample (n = 122) reported current, daily cannabis use and 63% reported pain as a motivation for use. Adults with persistent pain were more likely to be older, female, and have higher levels of education (p < .05). Adults with opioid use disorder were more likely to report "enhancement" (p < .01) and relief of drug withdrawal symptoms (p < .001) as motivations for cannabis use. The most common reasons for cannabis use in both populations were social and recreational use and pain relief.

CONCLUSIONS

Both studied populations have unmet health needs motivating them to use cannabis and commonly use cannabis for pain. Persistent pain participants were less likely to use cannabis for euphoric effects or withdrawal purposes. Nurses should assess for cannabis use, provide education on known risks and benefits, and offer options for holistic symptom management.

Evidence for the involvement of opioid and cannabinoid systems in the peripheral antinociception mediated by resveratrol

Despite all the development of modern medicine, around 100 compounds derived from natural products were undergoing clinical trials only at the end of 2013. Among these natural substances in clinical trials, we found the resveratrol (RES), a pharmacological multi-target drug. RES analgesic properties have been demonstrated, although the bases of these mechanisms have not been fully elucidated. The aim of this study was to evaluate the involvement of opioid and cannabinoid systems in RES-induced peripheral antinociception. Paw withdrawal method was used and hyperalgesia was induced by carrageenan (200 μg/paw). All drugs were given by intraplantar injection in male Swiss mice (n = 5). RES (100 μg/paw) administered in the right hind paw induced local antinociception that was antagonized by naloxone, non-selective opioid receptor antagonist, and clocinnamox, μOR selective antagonist. Naltrindole and nor-binaltorfimine, selective antagonists for δOR and kOR, respectively, did not reverse RES-induced peripheral antinociception. CB₁R antagonist AM251, but not CB₂R antagonist AM630, antagonized RES-induced peripheral antinociception. Peripheral antinociception of RES intermediate-dose (50 μg/paw) was increased by: (i) bestatin, inhibitor of endogenous opioid degradation involved-enzymes; (ii) MAFP, inhibitor of anandamide amidase; (iii) JZL184, inhibitor of 2-arachidonoylglycerol degradation involved-enzyme; (iv) VDM11, endocannabinoid reuptake inhibitor. Acute and peripheral administration of RES failed to affect the amount of μOR, CB₁R and CB₂R. Experimental data suggest that RES induces peripheral antinociception through μOR and CB₁R activation by endogenous opioid and endocannabinoid releasing.

The Prevalence of Nonprescription Cannabinoid-Based Medicines in British Children's Hospices: Results of a National Survey

Background: Almost 50,000 children and young people are affected by life-limiting conditions in the United Kingdom, around a third of which use children's hospices. Anecdotal evidence suggests that cannabinoid-based medicines (CBMs), specifically cannabis oil (CO), are being used by families with increasing frequency to manage distressing symptoms. The use of most nonprescription CBMs in the United Kingdom remains illegal. Objective: The objective of the study was to identify the prevalence of CO use by families who use children's hospices in the United Kingdom, and the approaches taken by those services to manage it. Design: An electronic survey was sent to each of the 54 children's hospices in the United Kingdom between May and July 2018, comprising 10 questions. Results: Forty children's hospices from across the four countries of the United Kingdom responded to the survey, representing 74% of British children's hospices. About 87.5% of hospices knew of children who use CO therapeutically. Sixty-nine percent of those hospices have received requests to administer CO during an episode of care. Approaches by organizations around CO management varied across the sectors, including arrangements for storage, administration, and recording of its use. Hospices highlighted how the lack of available guidance made decision making more challenging. Only a third of responding organizations routinely questioned families about the use of cannabis when prescribing medicines. Conclusion: CO is used extensively by children who use children's hospices. Despite recognizing the use of CO, many hospices are unable to support it. There is a need for clear guidelines on how hospices should approach the care needs of children, allowing hospices to meet the needs of children who use CO, and families in a safe, consistent, and relevant way, safeguarding all children, families, and professionals within the organization.

Substance-related disorders: A review of prevalence and correlates among patients with chronic pain

Over the past few decades, research has revealed high rates of substance-related disorders among patients with chronic pain. In addition to their potentially deleterious health consequences, substance-related disorders have consistently been associated with negative pain-related outcomes among patients with chronic pain. The goal of this narrative review was to provide an overview of studies that have examined the prevalence and correlates of substance-related disorders among patients with chronic pain. A particular focus was placed on opioids, sedatives/hypnotics, cannabis, tobacco, and alcohol given that these substances have received the bulk of research attention among patients with pain. Research conducted to date suggests that a host of biological and psychological factors are likely to contribute to the elevated rates of substance-related disorders among patients with chronic pain. In this review, in addition to reviewing the prevalence and correlates of substance-related disorders among patients with pain, we briefly discussed the changes that were recently made from the DSM-4 to the DSM-5 in the diagnostic criteria for substance-related disorders, and the implications of these changes for the assessment of patients with chronic pain. We also provided a brief overview of instruments that can be used for the assessment of these disorders in clinical and research settings.