A double-blind, randomized, placebo-controlled, parallel-group study of THC/CBD oromucosal spray in combination with the existing treatment regimen, in the relief of central neuropathic pain in patients with multiple sclerosis

UK medical cannabis registry: A clinical outcome analysis of medical cannabis therapy in chronic pain patients with and without co-morbid sleep impairment

INTRODUCTION

Chronic pain (CP) affects 35.0%-51.3% of the UK population, with 67%-88% reporting sleep disturbances. Cannabis-based medicinal products (CBMPs) have shown therapeutic potential in managing CP. Evidence suggests poor sleep worsens pain perception; therefore, this study aimed to assess patient-reported outcome measures (PROMs) following CBMP treatment in CP patients with and without co-morbid sleep impairment.

METHODS

A prospective cohort study of CP patients from the UK Medical Cannabis Registry was conducted. Participants were separated by baseline single-item sleep quality scale (SQS) score into sleep impaired (SQS ≤3) and unimpaired (SQS ≥4) cohorts. The primary outcome assessed changes in PROMs from baseline to 1-, 3-, 6-, and 12-months. Participants completed the following: SQS, General Anxiety Disorder-7, EQ-5D-5L, Brief Pain Inventory (BPI), and Short-Form McGill Pain Questionnaire-2. Significance was defined as p < 0.050.

RESULTS

1139 participants met the inclusion criteria (sleep impaired: n = 517, 45.4%; sleep unimpaired: n = 622, 54.61%). The sleep impaired cohort showed improvements in all PROMs at each follow-up (p < 0.010). The sleep unimpaired cohort showed similar results (p < 0.050), except in SQS and ED-5Q-5L: self-care and anxiety/depression scores (p > 0.050). However, the sleep impaired cohort observed greater improvements in BPI pain severity (p < 0.050) and SQS (p < 0.001) than the sleep unimpaired cohort at all follow-ups. 2817 adverse events were self-reported between both cohorts (p = 0.197).

DISCUSSION

These findings align with literature that shows associated improvements in pain outcomes following CBMP administration. Sleep impaired individuals were more likely to experience greater pain severity improvements. However, this was not confirmed on multivariate logistic regression analysis and instead may be confounded by baseline pain severity.

CONCLUSION

Whilst these results show promise for the effects of CBMPs on CP, they must be examined within the limitations of the study design. These findings provide further evidence to support the design of subsequent randomized controlled trials to verify causality between CBMPs and pain outcomes.

An overview on disease modifying and symptomatic drug treatments for multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is an inflammatory and degenerative autoimmune condition, resulting frequently in a disabling condition. Significant improvements of long-term prognosis have been recently achieved with an early and more aggressive use of disease modifying therapies (DMTs). Addressing the complexity of managing its progressive forms remains a significant challenge.

AREAS COVERED

This review provides an update on DMTs for relapsing-remitting MS (RRMS) and progressive MS and their efficacy, safety, and mechanism of action, emphasizing the critical role of biomarkers in optimizing treatment decisions. Moreover, some key information on drugs used to manage symptoms such as pain, fatigue, spasticity and urinary problems will be provided. The literature search was conducted using PubMed, Embase, and Cochrane Library databases covering the period from January 2000 to January 2024.

EXPERT OPINION

Major advances have been achieved in the treatment of RRMS. Treatment should start immediately as soon as the neurologist is confident with the diagnosis and its choice should be based on the prognostic profile and on the patient's propensity to accept drug-related risks. The therapeutic landscape for progressive MS is quite disappointing and necessitates further innovation. Personalized medicine, leveraging biomarker insights, holds promise for refining treatment efficacy and patient outcomes.

Chemotherapy-Induced Peripheral Neuropathy: A Recent Update on Pathophysiology and Treatment

Chemotherapy-induced peripheral neuropathy (CIPN) is a major long-lasting side effect of some chemotherapy drugs, which threatens cancer survival rate. CIPN mostly affects sensory neurons and occasionally motor neurons, causing numbness, tingling, discomfort, and burning pain in the upper and lower extremities. The pathophysiology of CIPN is not completely understood; however, it is believed that chemotherapies induce peripheral neuropathy via directly damaging mitochondria, impairing the function of ion channels, triggering immunological mechanisms, and disrupting microtubules. The treatment of CIPN is a medical challenge, and there are no approved pharmacological options. Currently, duloxetine and other antidepressants, antioxidant, anti-inflammatory, and ion-channel targeted therapies are commonly used in clinics to relieve the symptoms of CIPN. Several other types of drugs, such as cannabinoids, sigma-1 receptor antagonists, and nicotinamides ribose, are being evaluated in preclinical and clinical studies. This paper summarizes the information related to the physiology of CIPN and medicines that could be used for treating this condition.

Efficacy of cannabinoids compared to the current standard treatments on symptom relief in persons with multiple sclerosis (CANSEP trial): study protocol for a randomized clinical trial

Background

Multiple sclerosis (MS) is an inflammatory and degenerative disease of the central nervous system. More than 90,000 Canadians are affected; a cure is yet to be found. Available treatments to manage the disease course are only partially effective. For many years, persons with MS (PwMS) have used cannabis to relax, to reduce pain and spasticity, or to improve sleep and daily functioning, despite the lack of scientific evidence on the efficacy of specific cannabinoids [i.e., tetrahydrocannabinol (THC) and cannabidiol (CBD)] on these MS symptoms. The purpose of this clinical trial is to assess the effectiveness of different doses of these cannabinoids, alone or combined, on spasticity relief, compared to placebo. Moreover, we aim to determine which treatment is best effective to address other key MS conditions.

Methods

A double-blinded, randomized, factorial, placebo-controlled trial will be performed. We intend to include up to 250 PwMS aged over 21 recruited from the Centre hospitalier de l'Université de Montréal MS Clinic. PwMS will be randomly assigned on a 1:1:1:1 ratio to one of the trial arms: THC alone, CBD alone, THC/CBD combination, or placebo, using stratified blocked randomization, with random blocks within each stratum. The primary outcome is a self-assessment of spasticity using the mean Numeric Rating Scale score over 7 days. The main outcome will be the difference in this score at 4 weeks compared to baseline. Secondary outcomes include assessments of spasticity as measured by a clinician, pain, fatigue, sleep, bowel, bladder, and sexual dysfunction, restless legs syndrome, mental health, quality of life, mobility, cognitive functioning, and adverse events. Treatment responders are eligible for a 12-week extension phase, using the same treatment allocation and assessments.

Discussion

Previous clinical studies examined the efficacy of cannabis-based medicines in PwMS, mostly using products with 1:1 THC/CBD ratio. The major barrier to effectively use cannabis in real-world clinical settings is the lack of evidence on benefits of specific cannabinoids and information on possible related risks. The CANSEP study will contribute to overcome these limitations and identify the risks and benefits of cannabis-based treatments in PwMS.

Clinical trial registration

ClinicalTrials.Gov, NCT05092191.

Cannabidiol and pain

Chronic pain presents significant personal, psychological, and socioeconomic hurdles, impacting over 30% of adults worldwide and substantially contributing to disability. Unfortunately, current pharmacotherapy often proves inadequate, leaving fewer than 70% of patients with relief. This shortfall has sparked a drive to seek alternative treatments offering superior safety and efficacy profiles. Cannabinoid-based pharmaceuticals, notably cannabidiol (CBD), hold promise in pain management, driven by their natural origins, versatility, and reduced risk of addiction. As we navigate the opioid crisis, ongoing research plunges into CBD's therapeutic potential, buoyed by animal studies revealing its pain-relieving prowess through various system tweaks. However, the efficacy of cannabis in chronic pain management remains a contentious and stigmatized issue. The International Association for the Study of Pain (IASP) presently refrains from endorsing cannabinoid use for pain relief. Nevertheless, evidence indicates their potential in alleviating cancer-related, neuropathic, arthritis, and musculoskeletal pain, necessitating further investigation. Crucially, our comprehension of CBD's role in pain management is a journey still unfolding, with animal studies illustrating its analgesic effects through interactions with the endocannabinoid, inflammatory, and nociceptive systems. As the plot thickens, it's clear: the saga of chronic pain and CBD's potential offers a compelling narrative ripe for further exploration and understanding.

Evidence of Cannabidiol Effectiveness Associated or Not with Tetrahydrocannabinol in Topical Administration: A Scope Review

Cannabis sativa is a plant of the Cannabaceae family, whose molecular composition is known for its vast pharmacological properties. Cannabinoids are the molecules responsible for Cannabis sativa potential effects, especially tetrahydrocannabinol and cannabidiol. Scientific development has shown interest in the potential of cannabidiol in various health conditions, as it has demonstrated lower adverse events and great pharmacological potential, especially when administered topically. The present study aims to carry out a scoping review, focusing on the use of cannabidiol, in vivo models, for topical administration. Thus, the methodological approach used by the Joanna Briggs Institute was applied, and the studies were selected based on previously established inclusion criteria. Even though more information regarding the dose to achieve pharmacological potential is still needed, cannabidiol demonstrated potential in treating and preventing different conditions, such as glaucoma, atopic dermatitis, epidermolysis bullosa, and pyoderma gangrenosum.

An extract of phase II and III trials on recent developments in managing neuropathic pain syndromes: diabetic peripheral neuropathy, trigeminal neuralgia, and postherpetic neuralgia

INTRODUCTION

Neuropathic pain (NP) conditions involve lesions to the somatosensory nervous system leading to chronic and debilitating pain. Many patients suffering from NP utilize pharmacological treatments with various drugs that seek to reduce pathologic neuronal states. However, many of these drugs show poor efficacy as well as cause significant adverse effects. Because of this, there is a major need for the development of safer and more efficacious drugs to treat NP.

AREAS COVERED

In this review, we analyzed current treatments being developed for a variety of NP conditions. Specifically, we sought drugs in phase II/III clinical trials with indications for NP conditions. Various databases were searched including Google Scholar, PubMed, and clinicaltrials.gov.

EXPERT OPINION

All the mentioned targets for treatments of NP seem to be promising alternatives for existing treatments that often possess poor side effect profiles for patients. However, gene therapy potentially offers the unique ability to inject a plasmid containing growth factors leading to nerve growth and repair. Because of this, gene therapy appears to be the most intriguing new treatment for NP.

Effectiveness, Safety and Patients' Satisfaction of Nabiximols (Sativex®) on Multiple Sclerosis Spasticity and Related Symptoms in a Swiss Multicenter Study

Background: Cannabinoid oro-mucosal spray nabiximols is approved for patients with moderate to severe multiple sclerosis spasticity (MSS) resistant to other antispastic medications. Few real-world data are available on the effectiveness, safety and patients' satisfaction in MS patients treated with nabiximols as monotherapy. Methods: To investigate the effectiveness, tolerability and satisfaction of nabiximols in a real-life multicentric Swiss cohort as monotherapy or with stable doses of other antispastic medications, and explore clinical features which may predict treatment response. The following data were collected at treatment start (baseline) and 12 weeks thereafter: Modified Ashworth scale (MAS), scores at numerical rating scales ranging from 0 (absent) to 10 (considerable) for effect on spasticity (sNRS), pain (pNRS), gait (gNRS), urinary symptoms (uNRS), tolerability (tNRS) as assessed by the treating neurologist, and overall treatment satisfaction (TsNRS) and tolerability (tNRS) as assessed by the patient. Results: Ninety-five patients (44 relapsing remitting, 37 secondary progressive and 14 primary progressive MS; median age = 53 (IQR 45-62); female 70%; median EDSS 6 (IQR 4-6), concomitant antispastic treatments in 54% of patients) were included. From baseline to week 12, median MAS score decreased from 3.0 to 2.0 (p < 0.001). Median scores of the each NRS also significantly decreased (p < 0.001 for all comparisons). At week 12, the median TsNRS and tTS scores were 8/10 (IQR: 6-9) and 9/10 (IQR: 7-10), respectively, and 93.7% of patients continued to use nabiximols at the average dose of six sprays/day. No clinical factors, including use of nabiximols as add on vs. monotherapy, were associated with responder status. Conclusions: Our first Swiss, multicentric, observational, real-life study supports and enhances previous finding of nabiximols as monotherapy and as add-on therapy, being an effective, safe and well-tolerated treatment option for resistant MS spasticity and spasticity-related symptoms (pain, bladder dysfunction and gait).

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.

Phytocannabinoids for the Treatment of Neuropathic Pain: A Scoping Review of Randomised Controlled Trials Published Between 2012 and 2023

PURPOSE OF REVIEW

Neuropathic pain (NP) remains a challenge to treat, with 50% of patients experiencing limited efficacy from current treatments. Medicinal cannabis, which contains tetrahydrocannabinol (THC), cannabidiol (CBD) and other minor cannabinoids, is garnering attention as an alternative treatment for NP. This paper reviews the clinical evidence for phytocannabinoid treatment of NP.

RECENT FINDINGS

Seventeen randomised controlled trials (RCT) were identified for inclusion in this review. Of these, ten studies using phytocannabinoid preparations containing THC alone had the most evidence for pain relief. Four studies investigating THC/CBD combinations showed some reductions in pain scores, although not all findings were statistically significant, whereas studies investigating CBD (two studies) or cannabidivarin (one study) showed no analgesic effect over placebo. However, CBD studies were of small sample size when compared to other studies in the review and short duration. Results for treatment of diabetic peripheral neuropathy patients with THC showed better improvements over those for NP induced by chemotherapy and multiple sclerosis, with these trials using vaporised whole plant cannabis. This formulation may have trace amounts of other minor cannabinoids, compared with synthetic cannabinoids such as dronabinol or nabilone that were investigated in other studies. This review provides an overview of RCTs that have investigated phytocannabinoid use for the treatment of NP. There appears to be evidence to necessitate further high quality RCTs into novel formulations of phytocannabinoids for the treatment of NP.

Tetrahydrocannabinol and Cannabidiol for Pain Treatment-An Update on the Evidence

In light of the current International Association for the Study of Pain (IASP) clinical practice guidelines (CPGs) and the European Society for Medical Oncology (ESMO) guidelines, the topic of cannabinoids in relation to pain remains controversial, with insufficient research presently available. Cannabinoids are an attractive pain management option due to their synergistic effects when administered with opioids, thereby also limiting the extent of respiratory depression. On their own, however, cannabinoids have been shown to have the potential to relieve specific subtypes of chronic pain in adults, although controversies remain. Among these subtypes are neuropathic, musculoskeletal, cancer, and geriatric pain. Another interesting feature is their effectiveness in chemotherapy-induced peripheral neuropathy (CIPN). Analgesic benefits are hypothesized to extend to HIV-associated neuropathic pain, as well as to lower back pain in the elderly. The aim of this article is to provide an up-to-date review of the existing preclinical as well as clinical studies, along with relevant systematic reviews addressing the roles of various types of cannabinoids in neuropathic pain settings. The impact of cannabinoids in chronic cancer pain and in non-cancer conditions, such as multiple sclerosis and headaches, are all discussed, as well as novel techniques of administration and relevant mechanisms of action.

Medicinal Plants for the Treatment of Neuropathic Pain: A Review of Randomized Controlled Trials

Neuropathic pain is a disabling condition caused by various diseases and can profoundly impact the quality of life. Unfortunately, current treatments often do not produce complete amelioration and can be associated with potential side effects. Recently, herbal drugs have garnered more attention as an alternative or a complementary treatment. In this article, we summarized the results of randomized clinical trials to evaluate the effects of various phytomedicines on neuropathic pain. In addition, we discussed their main bioactive components and potential mechanisms of action to provide a better view of the application of herbal drugs for treating 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.

Medical Cannabis Increases Appetite but Not Body Weight in Patients with Inflammatory Bowel Diseases

We aimed to elucidate the effect of Medical Cannabis (MC) on appetite and nutritional status among patients with inflammatory bowel disease (IBD). A case series of patients with IBD were initiating treatment with MC for disease-related symptoms, at the IBD clinic of a tertiary referral medical center. Patients' demographics, anthropometrics, medical history and treatment and MC use were systematically recorded. An appetite and food frequency questionnaire (SNAQ and FFQ) were filled before, and at 3 and 6 months of treatment. Patients with IBD initiating MC were enrolled (n = 149, age 39.0 ± 14.1 years, 42.3% female), and 33.6% (n = 50) were treated for improvement of nutritional status. A modest increase in appetite after 3 months was detected among all patients enrolled (Pv = 0.08), but there were no significant differences in energy or macronutrient intake, and in patients' body mass index (BMI). A significant appetite improvement after 3 months was detected among 34.0% (n = 17) of patients, but this was not associated with increased caloric intake or BMI at 3 or 6 months. Among patients without increased appetite after 3 months of MC therapy, BMI decreased at 6 months (24.1 ± 3.7 vs. 23.4 ± 3.6, Pv = 0.010). MC may be a potential strategy to improve appetite among some patients with IBD, but not caloric intake or BMI.

Unlocking the Healing Potential: Cannabinoids in Spine Surgery for Pain Relief and Recovery

» Cannabinoids, such as D9-tetrahydrocannabinol and cannabidiol, interact with endocannabinoid receptors in the central nervous system and immune system, potentially offering pain relief. The entourage effect, resulting from the interaction of multiple cannabis components, may enhance therapeutic impact and efficacy, making them promising candidates for exploring pain relief in spine operations, known to be among the most painful operative procedures.» The use of cannabinoids in pain management requires careful consideration of safety, including their cognitive and psychomotor effects, potential cardiovascular risks, risk of dependence, mental health implications, and drug interactions.» Few studies have analyzed cannabinoid use in relation to spine surgery, with variable results reported, indicating possible effects on reoperation rates, mortality, complications, postoperative opioid use, and length of hospital stay.» Current knowledge gaps exist in the understanding of cannabinoid effects on spine surgery, including the exploration of different administration routes, timing, dosage, and specific outcomes. In addition, mechanistic explanations for the observed results are lacking.» Ethical considerations related to informed consent, medical expertise, societal impact, and legal compliance must also be thoroughly addressed when considering the utilization of cannabinoids in spinal pathologies and back pain treatment.

Reactive nitrogen species as therapeutic targets for autophagy/mitophagy modulation to relieve neurodegeneration in multiple sclerosis: Potential application for drug discovery

Multiple sclerosis (MS) is a neuroinflammatory disease with limited therapeutic effects, eventually developing into handicap. Seeking novel therapeutic strategies for MS is timely important. Active autophagy/mitophagy could mediate neurodegeneration, while its roles in MS remain controversial. To elucidate the exact roles of autophagy/mitophagy and reveal its in-depth regulatory mechanisms, we conduct a systematic literature study and analyze the factors that might be responsible for divergent results obtained. The dynamic change levels of autophagy/mitophagy appear to be a determining factor for final neuron fate during MS pathology. Excessive neuronal autophagy/mitophagy contributes to neurodegeneration after disease onset at the active MS phase. Reactive nitrogen species (RNS) serve as key regulators for redox-related modifications and participate in autophagy/mitophagy modulation in MS. Nitric oxide (•NO) and peroxynitrite (ONOO-), two representative RNS, could nitrate or nitrosate Drp1/parkin/PINK1 pathway, activating excessive mitophagy and aggravating neuronal injury. Targeting RNS-mediated excessive autophagy/mitophagy could be a promising strategy for developing novel anti-MS drugs. In this review, we highlight the important roles of RNS-mediated autophagy/mitophagy in neuronal injury and review the potential therapeutic compounds with the bioactivities of inhibiting RNS-mediated autophagy/mitophagy activation and attenuating MS progression. Overall, we conclude that reactive nitrogen species could be promising therapeutic targets to regulate autophagy/mitophagy for multiple sclerosis treatment.

In Vitro and In Vivo Anti-Inflammatory Effects of Cannabidiol Isolated from Novel Hemp (Cannabis sativa L.) Cultivar Pink Pepper

Cannabis sativa L. contains more than 80 cannabinoids, among which cannabidiol (CBD) is the main neuroactive component. We aimed to investigate the anti-inflammatory efficacy of CBD in vitro and in vivo isolated from "Pink pepper", a novel hemp cultivar, by repeating the method of selecting and cultivating individuals with the highest CBD content. We investigated the effects of CBD on inflammatory markers elevated by lipopolysaccharide (LPS) treatment in RAW 264.7 mouse macrophage cells through Western blot and RT-PCR. In addition, we confirmed these effects through the ELISA of inflamed paw tissue of a λ-carrageenan-induced mouse edema model that received an oral administration of CBD. CBD inhibited the LPS-induced phosphorylation of NF-κB and MAPK in RAW 264.7 and exhibited anti-inflammatory effects by participating in these pathways. In our in vivo study, we confirmed that CBD also inhibited the inflammatory mediators of proteins extracted from edematous mouse paw tissue. These results show that CBD isolated from "Pink pepper" exhibits potent anti-inflammatory effects. These anti-inflammatory effects of CBD have pharmacological and physiological significance, highlighting the industrial value of this novel cultivar.

Cannabis-Based Medicine for Neuropathic Pain and Spasticity-A Multicenter, Randomized, Double-Blinded, Placebo-Controlled Trial

Patients with multiple sclerosis (MS) and spinal cord injury (SCI) commonly sustain central neuropathic pain (NP) and spasticity. Despite a lack of consistent evidence, cannabis-based medicine (CBM) has been suggested as a supplement treatment. We aimed to investigate the effect of CBM on NP and spasticity in patients with MS or SCI. We performed a randomized, double-blinded, placebo-controlled trial in Denmark. Patients aged ≥18 years with NP (intensity >3, ≤9 on a numerical rating scale (NRS0-10) and/or spasticity (>3 on NRS0-10) were randomized to treatment consisting of either delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), a combination of THC&CBD in maximum doses of 22.5 mg, 45 mg and 22.5/45 mg per day, respectively, or placebo. A baseline registration was performed before randomization. Treatment duration was six weeks followed by a one-week phaseout. Primary endpoints were the intensity of patient-reported NP and/or spasticity. Between February 2019 and December 2021, 134 patients were randomized (MS n = 119, SCI n = 15), where 32 were assigned to THC, 31 to CBD, 31 to THC&CBD, and 40 to placebo. No significant difference was found for: mean pain intensity (THC 0.42 (-0.54-1.38), CBD 0.45 (-0.47-1.38) and THC&CBD 0.16 (-0.75-1.08)), mean spasticity intensity (THC 0.24 (-0.67-1.45), CBD 0.46 (-0.74-1.65), and THC&CBD 0.10 (-1.18-1.39), secondary outcomes (patient global impression of change and quality of life), or any tertiary outcomes. We aimed to include 448 patients in the trial; however, due to COVID-19 and recruitment challenges, fewer were included. Nevertheless, in this four-arm parallel trial, no effect was found between placebo and active treatment with THC or CBD alone or in combination on NP or spasticity in patients with either MS or SCI. The trial was registered with the EU Clinical Trials Register EudraCT (2018-002315-98).

Cannabis and sleep disorders: not ready for prime time? A qualitative scoping review

STUDY OBJECTIVES

To perform a qualitative scoping literature review for studies involving the effects of cannabis on sleep and sleep disorders.

METHODS

Two electronic databases, MEDLINE and EMBASE, searched for comprehensive published abstracted studies that involved human participants. Inclusion criteria were article of any type, published in English, a target population of cannabis users, and reported data on cannabis effect on sleep and sleep disorders. The Joanna Briggs Institute's (JBI) approach was elected as the methodology framework guidance in the scoping review process.

RESULTS

A total of 40 unique publications were found. The majority (82.5%) were from the Americas with 60% published in the last decade. Of the 40 studies, only 25% were randomized control trials, and the sleep outcome measurements were similar and comparable in only 20%. Cannabis users studied were reported either 73% frequent users or 27% sporadic users. The utilization of cannabis showed improved sleep (21%), worse sleep (48%), mixed results (14%), or no impact at all (17%) in the studies published in the last 5 decades.

CONCLUSIONS

Our findings summarize the lack of robust evidence to support the use of cannabis for sleep disorders. The varied cannabis user-related characteristics may account for the inconsistent results identified. Further studies assessing cannabis and sleep are needed to discern what works in what context, how it works, and for whom.

CITATION

Amaral C, Carvalho C, Scaranelo A, Chapman K, Chatkin J, Ferreira I. Cannabis and sleep disorders: not ready for prime time? A qualitative scoping review. J Clin Sleep Med. 2023;19(5):975-990.

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

BACKGROUND

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

OBJECTIVE

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

EVIDENCE REVIEW

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

FINDINGS

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

CONCLUSIONS

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

PROSPERO REGISTRATION NUMBER

CRD42017074255.

An update on animal models of intervertebral disc degeneration and low back pain: Exploring the potential of artificial intelligence to improve research analysis and development of prospective therapeutics

Animal models have been invaluable in the identification of molecular events occurring in and contributing to intervertebral disc (IVD) degeneration and important therapeutic targets have been identified. Some outstanding animal models (murine, ovine, chondrodystrophoid canine) have been identified with their own strengths and weaknesses. The llama/alpaca, horse and kangaroo have emerged as new large species for IVD studies, and only time will tell if they will surpass the utility of existing models. The complexity of IVD degeneration poses difficulties in the selection of the most appropriate molecular target of many potential candidates, to focus on in the formulation of strategies to effect disc repair and regeneration. It may well be that many therapeutic objectives should be targeted simultaneously to effect a favorable outcome in human IVD degeneration. Use of animal models in isolation will not allow resolution of this complex issue and a paradigm shift and adoption of new methodologies is required to provide the next step forward in the determination of an effective repairative strategy for the IVD. AI has improved the accuracy and assessment of spinal imaging supporting clinical diagnostics and research efforts to better understand IVD degeneration and its treatment. Implementation of AI in the evaluation of histology data has improved the usefulness of a popular murine IVD model and could also be used in an ovine histopathological grading scheme that has been used to quantify degenerative IVD changes and stem cell mediated regeneration. These models are also attractive candidates for the evaluation of novel anti-oxidant compounds that counter inflammatory conditions in degenerate IVDs and promote IVD regeneration. Some of these compounds also have pain-relieving properties. AI has facilitated development of facial recognition pain assessment in animal IVD models offering the possibility of correlating the potential pain alleviating properties of some of these compounds with IVD regeneration.

Intervertebral disc degeneration and how it leads to low back pain

The purpose of this review was to evaluate data generated by animal models of intervertebral disc (IVD) degeneration published in the last decade and show how this has made invaluable contributions to the identification of molecular events occurring in and contributing to pain generation. IVD degeneration and associated spinal pain is a complex multifactorial process, its complexity poses difficulties in the selection of the most appropriate therapeutic target to focus on of many potential candidates in the formulation of strategies to alleviate pain perception and to effect disc repair and regeneration and the prevention of associated neuropathic and nociceptive pain. Nerve ingrowth and increased numbers of nociceptors and mechanoreceptors in the degenerate IVD are mechanically stimulated in the biomechanically incompetent abnormally loaded degenerate IVD leading to increased generation of low back pain. Maintenance of a healthy IVD is, thus, an important preventative measure that warrants further investigation to preclude the generation of low back pain. Recent studies with growth and differentiation factor 6 in IVD puncture and multi-level IVD degeneration models and a rat xenograft radiculopathy pain model have shown it has considerable potential in the prevention of further deterioration in degenerate IVDs, has regenerative properties that promote recovery of normal IVD architectural functional organization and inhibits the generation of inflammatory mediators that lead to disc degeneration and the generation of low back pain. Human clinical trials are warranted and eagerly anticipated with this compound to assess its efficacy in the treatment of IVD degeneration and the prevention of the generation of low back pain.

Cannabinoids to Improve Health-Related Quality of Life in Patients with Neurological or Oncological Disease: A Meta-Analysis

Background: Cannabinoids have been suggested to alleviate frequently experienced symptoms of reduced mental well-being such as anxiety and depression. Mental well-being is an important subdomain of health-related quality of life (HRQoL). Reducing symptoms and maintaining HRQoL are particularly important in malignant primary brain tumor patients, as treatment options are often noncurative and prognosis remains poor. These patients frequently report unprescribed cannabinoid use, presumably for symptom relieve. As studies on brain tumor patients specifically are lacking, we performed a meta-analysis of the current evidence on cannabinoid efficacy on HRQoL and mental well-being in oncological and neurological patients. Methods: We performed a systematic PubMed, PsychINFO, Embase, and Web of Science search according to PRISMA guidelines on August 2 and 3, 2021. We included randomized controlled trials (RCTs) that assessed the effects of tetrahydrocannabinol (THC) or cannabidiol (CBD) on general HRQoL and mental well-being. Pooled effect sizes were calculated using Hedges g. Risk of bias of included studies was assessed using Cochrane's Risk of Bias tool. Results: We included 17 studies: 4 in oncology and 13 in central nervous system (CNS) disease. Meta-analysis showed no effect of cannabinoids on general HRQoL (g=-0.02 confidence interval [95% CI -0.11 to 0.06]; p=0.57) or mental well-being (g=-0.02 [95% CI -0.16 to 0.13]; p=0.81). Conclusions: RCTs in patients with cancer or CNS disease showed no effect of cannabinoids on HRQoL or mental well-being. However, studies were clinically heterogeneous and since many glioma patients currently frequently use cannabinoids, future studies are necessary to evaluate its value in this specific population.

Cannabinoids versus placebo for pain: A systematic review with meta-analysis and Trial Sequential Analysis

OBJECTIVES

To assess the benefits and harms of cannabinoids in participants with pain.

DESIGN

Systematic review of randomised clinical trials with meta-analysis, Trial Sequential Analysis, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

DATA SOURCES

The Cochrane Library, MEDLINE, Embase, Science Citation Index, and BIOSIS.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Published and unpublished randomised clinical trials comparing cannabinoids versus placebo in participants with any type of pain.

MAIN OUTCOME MEASURES

All-cause mortality, pain, adverse events, quality of life, cannabinoid dependence, psychosis, and quality of sleep.

RESULTS

We included 65 randomised placebo-controlled clinical trials enrolling 7017 participants. Fifty-nine of the trials and all outcome results were at high risk of bias. Meta-analysis and Trial Sequential Analysis showed no evidence of a difference between cannabinoids versus placebo on all-cause mortality (RR 1.20; 98% CI 0.85 to 1.67; P = 0.22). Meta-analyses and Trial Sequential Analysis showed that cannabinoids neither reduced acute pain (mean difference numerical rating scale (NRS) 0.52; 98% CI -0.40 to 1.43; P = 0.19) or cancer pain (mean difference NRS -0.13; 98% CI -0.33 to 0.06; P = 0.1) nor improved quality of life (mean difference -1.38; 98% CI -11.81 to 9.04; P = 0.33). Meta-analyses and Trial Sequential Analysis showed that cannabinoids reduced chronic pain (mean difference NRS -0.43; 98% CI -0.72 to -0.15; P = 0.0004) and improved quality of sleep (mean difference -0.42; 95% CI -0.65 to -0.20; P = 0.0003). However, both effect sizes were below our predefined minimal important differences. Meta-analysis and Trial Sequential Analysis indicated that cannabinoids increased the risk of non-serious adverse events (RR 1.20; 95% CI 1.15 to 1.25; P < 0.001) but not serious adverse events (RR 1.18; 98% CI 0.95 to 1.45; P = 0.07). None of the included trials reported on cannabinoid dependence or psychosis.

CONCLUSIONS

Cannabinoids reduced chronic pain and improved quality of sleep, but the effect sizes are of questionable importance. Cannabinoids had no effects on acute pain or cancer pain and increased the risks of non-serious adverse events. The harmful effects of cannabinoids for pain seem to outweigh the potential benefits.

Cannabinoids in neuroinflammatory disorders: Focusing on multiple sclerosis, Parkinsons, and Alzheimers diseases

The medicinal properties of cannabis and cannabinoid-derivative are entirely investigated and known. In addition, the identification of psychotropic plant cannabinoids has led to more studies regarding the cannabinoid system and its therapeutic features in the treatment and management of clinical symptoms of neuroinflammatory disorders, such as multiple sclerosis (MS), Parkinsons disease (PD), and Alzheimers disease (AD). In fact, cannabinoid agonists are able to control and regulate inflammatory responses. In contrast to the cannabinoid receptor type 1 (CB1) and its unwanted adverse effects, the cannabinoid receptor type 2 (CB2) and its ligands hold promise for new and effective therapeutic approaches. So far, some successes have been achieved in this field. This review will discuss an outline of the endocannabinoid system's involvement in neuroinflammatory disorders. Moreover, the pharmacological efficacy of different natural and synthetic preparations of phytocannabinoids acting on cannabinoid receptors, particularly in MS, PD, and AD, will be updated. Also, the reasons for targeting CB2 for neurodegeneration will be explained.

Nabiximols is Efficient as Add-On Treatment for Patients with Multiple Sclerosis Spasticity Refractory to Standard Treatment: A Systematic Review and Meta-Analysis of Randomised Clinical Trials

BACKGROUND

Spasticity affects 54% of multiple sclerosis (MS) patients at disease onset, but this rate gradually increases with disease progression. Spasticity does not fully respond to standard treatment in one-third of the patients.

OBJECTIVE

Our systematic review and meta-analysis assessed whether add-on nabiximols, can improve MS-associated refractory spasticity.

METHODS

The systematic literature search was performed in Web of Science, MEDLINE, Scopus, CENTRAL, and Embase, on 15/10/2021, without restrictions. We included in the review blinded, randomized, placebo-controlled trials evaluating the efficacy of nabiximols in adult MS patients with refractory spasticity, by comparison with placebo. The primary outcome was responder rate by spasticity numerical rating scale (NRS). Secondary outcomes were spasticity-related parameters. We used random effect models to calculate odds ratios (OR) or mean differences and the corresponding 95% CI. Bias-factors were assessed with Cochrane risk of bias tool (RoB2). (PROSPERO ID: CRD42021282177).

RESULTS

We identified 9 eligible articles, of which 7 (1128 patients) were included in the meta-analysis. The spasticity numerical rating scale (NRS) was significantly higher in the nabiximols group than in the placebo group (OR 2.41 (95% CI 1.39; 4.18)). Secondary outcomes were in accordance with our primary results. At least some concerns were detected in the risk of bias analysis.

CONCLUSION

Our results indicate that nabiximols is efficient in MS associated spasticity, refractory to standard treatment and it may be considered as add-on symptomatic therapy. Nevertheless, further studies are needed to establish the optimal treatment protocol - dose, duration, moment of initiation, disease type.

Dysmenorrhoea: Can Medicinal Cannabis Bring New Hope for a Collective Group of Women Suffering in Pain, Globally?

Dysmenorrhoea effects up to 90% of women of reproductive age, with medical management options including over-the-counter analgesia or hormonal contraception. There has been a recent surge in medicinal cannabis research and its analgesic properties. This paper aims to critically investigate the current research of medicinal cannabis for pain relief and to discuss its potential application to treat dysmenorrhoea. Relevant keywords, including medicinal cannabis, pain, cannabinoids, tetrahydrocannabinol, dysmenorrhoea, and clinical trial, have been searched in the PubMed, EMBASE, MEDLINE, Google Scholar, Cochrane Library (Wiley) databases and a clinical trial website (clinicaltrials.gov). To identify the relevant studies for this paper, 84 papers were reviewed and 20 were discarded as irrelevant. This review critically evaluated cannabis-based medicines and their mechanism and properties in relation to pain relief. It also tabulated all clinical trials carried out investigating medicinal cannabis for pain relief and highlighted the side effects. In addition, the safety and toxicology of medicinal cannabis and barriers to use are highlighted. Two-thirds of the clinical trials summarised confirmed positive analgesic outcomes, with major side effects reported as nausea, drowsiness, and dry mouth. In conclusion, medicinal cannabis has promising applications in the management of dysmenorrhoea. The global medical cannabis market size was valued at USD 11.0 billion in 2021 and is expected to expand at a compound annual growth rate (CAGR) of 21.06% from 2022 to 2030. This will encourage academic as well as the pharmaceutical and medical device industries to study the application of medical cannabis in unmet clinical disorders.

Safety and Tolerability of Oral Cannabinoids in People Living with HIV on Long-Term ART: A Randomized, Open-Label, Interventional Pilot Clinical Trial (CTNPT 028)

BACKGROUND

With anti-inflammatory properties, cannabinoids may be a potential strategy to reduce immune activation in people living with HIV (PLWH) but more information on their safety and tolerability is needed.

METHODS

We conducted an open-label interventional pilot study at the McGill University Health Centre in Montreal, Canada. PLWH were randomized to oral Δ9-tetrahydrocannabinol (THC): cannabidiol (CBD) combination (THC 2.5 mg/CBD 2.5 mg) or CBD-only capsules (CBD 200 mg). Individuals titrated doses as tolerated to a maximum daily dose THC 15 mg/CBD 15 mg or 800 mg CBD, respectively, for 12 weeks. The primary outcome was the percentage of participants without any significant toxicity based on the WHO toxicity scale (Grades 0-2 scores).

RESULTS

Out of ten individuals, eight completed the study. Two from the CBD-only arm were withdrawn for safety concerns: phlebotomy aggravating pre-existing anemia and severe hepatitis on 800 mg CBD with newly discovered pancreatic adenocarcinoma, respectively. Seven did not have any significant toxicity. Cannabinoids did not alter hematology/biochemistry profiles. CD4 count, CD4/CD8 ratio, and HIV suppression remained stable. Most adverse effects were mild-moderate.

CONCLUSIONS

In PLWH, cannabinoids seem generally safe and well-tolerated, though larger studies are needed. Screening for occult liver pathology should be performed and hepatic enzymes monitored, especially with high CBD doses.

Effects of SativexⓇ on cognitive function in patients with multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

Cognitive impairment is a common manifestation of multiple sclerosis (MS).

OBJECTIVE

To assess by systematic review and meta-analysis available evidence regarding the impact of nabiximols oromucosal spray on cognition in patients with MS.

METHODS

A systematic literature search of clinical studies (all types, any comparator) that measured cognitive function in patients with MS spasticity treated with nabiximols. Meta-analysis for cognitive endpoints was not possible due to heterogenous measurement instruments and outcomes. Meta-analysis was performed for adverse events (AEs) of special interest (cognition disorders) reported in randomized controlled trials (RCTs) of nabiximols versus placebo in patients with MS (with or without spasticity). Certainty of evidence and risk of bias were assessed.

RESULTS

Seven clinical studies (three RCTs) directly assessing cognitive function were included in the qualitative analysis. There was no consistent evidence to suggest that nabiximols causes cognitive impairment as assessed by a range of specific psychometric instruments across cognitive domains. Thirteen double-blind, placebo-controlled RCTs (nabiximols, n = 964; placebo, n = 904) were included in the meta-analysis of cognitive AEs. Most cognitive AEs (30 of 32 events, 93.8%) reported with nabiximols in MS patients occurred with not in-label use, i.e., dosage >12 sprays per day and/or not administered primarily for treatment of spasticity.

CONCLUSIONS

Within the limitations of the review, we can conclude that no detrimental effects of nabiximols on cognitive function were observed in patients with MS spasticity during up to 12 months follow-up and that cognitive AEs were rare and occurred only when nabiximols was not used according to its approved label.

Cannabis dosing and administration for sleep: a systematic review

STUDY OBJECTIVES

As cannabis is increasingly used to treat sleep disorders, we performed a systematic review to examine the effects of cannabis on sleep and to guide cannabis prescribers in their recommendations to patients, specifically focusing on dosing.

METHODS

We searched EMBASE, Medline, and Web of Science and identified 4550 studies for screening. Five hundred sixty-eight studies were selected for full-text review and 31 were included for analysis. Study results were considered positive based on improvements in sleep architecture or subjective sleep quality. Bias in randomized controlled trials was assessed using Cochrane Risk of Bias tool 2.0.

RESULTS

Sleep improvements were seen in 7 out of 19 randomized studies and in 7 out of 12 uncontrolled trials. There were no significant differences between the effects of tetrahydrocannabinol and cannabidiol. Cannabis showed most promise at improving sleep in patients with pain-related disorders, as compared to those with neurologic, psychiatric, or sleep disorders, and showed no significant effects on healthy participants' sleep. While subjective improvements in sleep quality were often observed, diagnostic testing showed no improvements in sleep architecture. Adverse events included headaches, sedation, and dizziness, and occurred more frequently at higher doses, though no serious adverse events were observed.

CONCLUSION

High-quality evidence to support cannabis use for sleep remains limited. Heterogeneity in cannabis types, doses, timing of administration, and sleep outcome measures limit the ability to make specific dosing recommendations.

CDC Clinical Practice Guideline for Prescribing Opioids for Pain - United States, 2022

This guideline provides recommendations for clinicians providing pain care, including those prescribing opioids, for outpatients aged ≥18 years. It updates the CDC Guideline for Prescribing Opioids for Chronic Pain - United States, 2016 (MMWR Recomm Rep 2016;65[No. RR-1]:1-49) and includes recommendations for managing acute (duration of <1 month), subacute (duration of 1-3 months), and chronic (duration of >3 months) pain. The recommendations do not apply to pain related to sickle cell disease or cancer or to patients receiving palliative or end-of-life care. The guideline addresses the following four areas: 1) determining whether or not to initiate opioids for pain, 2) selecting opioids and determining opioid dosages, 3) deciding duration of initial opioid prescription and conducting follow-up, and 4) assessing risk and addressing potential harms of opioid use. CDC developed the guideline using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Recommendations are based on systematic reviews of the scientific evidence and reflect considerations of benefits and harms, patient and clinician values and preferences, and resource allocation. CDC obtained input from the Board of Scientific Counselors of the National Center for Injury Prevention and Control (a federally chartered advisory committee), the public, and peer reviewers. CDC recommends that persons with pain receive appropriate pain treatment, with careful consideration of the benefits and risks of all treatment options in the context of the patient's circumstances. Recommendations should not be applied as inflexible standards of care across patient populations. This clinical practice guideline is intended to improve communication between clinicians and patients about the benefits and risks of pain treatments, including opioid therapy; improve the effectiveness and safety of pain treatment; mitigate pain; improve function and quality of life for patients with pain; and reduce risks associated with opioid pain therapy, including opioid use disorder, overdose, and death.

Placebo Response and Media Attention in Randomized Clinical Trials Assessing Cannabis-Based Therapies for Pain: A Systematic Review and Meta-analysis

IMPORTANCE

Persistent pain is a common and disabling health problem that is often difficult to treat. There is an increasing interest in medicinal cannabis for treatment of persistent pain; however, the limited superiority of cannabinoids over placebo in clinical trials suggests that positive expectations may contribute to the improvements.

OBJECTIVE

To evaluate the size of placebo responses in randomized clinical trials in which cannabinoids were compared with placebo in the treatment of pain and to correlate these responses to objective estimates of media attention.

DATA SOURCES

A systematic literature search was conducted within the MEDLINE and Embase databases. Studies published until September 2021 were considered.

STUDY SELECTION

Cannabinoid studies with a double-blind, placebo-controlled design with participants 18 years or older with clinical pain of any duration were included. Studies were excluded if they treated individuals with HIV/AIDS or severe skin disorders.

DATA EXTRACTION AND SYNTHESIS

The study followed the Preferred Reporting Items for Systematic Review and Meta-analyses reporting guideline. Data were extracted by independent reviewers. Quality assessment was performed using the Risk of Bias 2 tool. Attention and dissemination metrics for each trial were extracted from Altmetric and Crossref. Data were pooled and analyzed using a random-effects statistical model.

MAIN OUTCOMES AND MEASURES

Change in pain intensity from before to after treatment, measured as bias-corrected standardized mean difference (Hedges g).

RESULTS

Twenty studies, including 1459 individuals (mean [SD] age, 51 [7] years; age range, 33-62 years; 815 female [56%]), were included. Pain intensity was associated with a significant reduction in response to placebo, with a moderate to large effect size (mean [SE] Hedges g, 0.64 [0.13]; P < .001). Trials with low risk of bias had greater placebo responses (q1 = 5.47; I2 = 87.08; P = .02). The amount of media attention and dissemination linked to each trial was proportionally high, with a strong positive bias, but was not associated with the clinical outcomes.

CONCLUSIONS AND RELEVANCE

Placebo contributes significantly to pain reduction seen in cannabinoid clinical trials. The positive media attention and wide dissemination may uphold high expectations and shape placebo responses in future trials, which has the potential to affect the outcome of clinical trials, regulatory decisions, clinical practice, and ultimately patient access to cannabinoids for pain relief.

Use of Cannabidiol in the Management of Insomnia: A Systematic Review

Background: Cannabidiol (CBD), one of the major cannabinoids derived from the cannabis plant, is available over the counter. CBD is often used by patients for the management of insomnia, yet research supporting CBDs effectiveness as a treatment for insomnia is inadequate. Objective: The objective of this review was to critically evaluate the literature regarding the therapeutic benefits of CBD in the management of insomnia. Methods: A comprehensive search of the following databases from inception to December 29, 2021, was conducted: Ovid MEDLINE^® and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus. The search included randomized controlled trials, nonrandomized experimental studies, cross-sectional studies, cohort studies, case series, and case reports. Risk of bias was assessed with the Agency for Healthcare Research and Quality design-specific recommended criteria. Results: Thirty-four studies were eligible for inclusion. All studies reported improvement in the insomnia symptoms of at least a portion of their participants. Of the 34 studies, 19 studies used CBD predominant therapy and 21 studies used nearly equal ratios of CBD to Δ⁹-tetrahydrocannabinol (THC). Of the studies that performed hypothesis testing, 4 of 7 studies with a CBD predominant arm and 12 of 16 studies with a nearly equal ratio of CBD to THC arm reported significant improvement in insomnia outcomes. However, only 2 of the 34 studies focused on patients with insomnia, of which 1 study was a case report. Additionally, several studies used nonvalidated subjective measures, and most studies failed to include objective measures for symptom assessment. Conclusions: The results of our systematic review suggest that CBD alone or with equal quantities of THC may be beneficial in alleviating the symptoms of insomnia. Nevertheless, future research assessing CBDs effectiveness in population of patients specifically with insomnia utilizing validated subjective and objective measures is necessary before definitive inferences can be made.

Medical cannabinoids: a pharmacology-based systematic review and meta-analysis for all relevant medical indications

BACKGROUND

Medical cannabinoids differ in their pharmacology and may have different treatment effects. We aimed to conduct a pharmacology-based systematic review (SR) and meta-analyses of medical cannabinoids for efficacy, retention and adverse events.

METHODS

We systematically reviewed (registered at PROSPERO: CRD42021229932) eight databases for randomized controlled trials (RCTs) of dronabinol, nabilone, cannabidiol and nabiximols for chronic pain, spasticity, nausea /vomiting, appetite, ALS, irritable bowel syndrome, MS, Chorea Huntington, epilepsy, dystonia, Parkinsonism, glaucoma, ADHD, anorexia nervosa, anxiety, dementia, depression, schizophrenia, PTSD, sleeping disorders, SUD and Tourette. Main outcomes and measures included patient-relevant/disease-specific outcomes, retention and adverse events. Data were calculated as standardized mean difference (SMD) and ORs with confidence intervals (CI) via random effects. Evidence quality was assessed by the Cochrane Risk of Bias and GRADE tools.

RESULTS

In total, 152 RCTs (12,123 participants) were analysed according to the type of the cannabinoid, outcome and comparator used, resulting in 84 comparisons. Significant therapeutic effects of medical cannabinoids show a large variability in the grade of evidence that depends on the type of cannabinoid. CBD has a significant therapeutic effect for epilepsy (SMD - 0.5[CI - 0.62, - 0.38] high grade) and Parkinsonism (- 0.41[CI - 0.75, - 0.08] moderate grade). There is moderate evidence for dronabinol for chronic pain (- 0.31[CI - 0.46, - 0.15]), appetite (- 0.51[CI - 0.87, - 0.15]) and Tourette (- 1.01[CI - 1.58, - 0.44]) and moderate evidence for nabiximols on chronic pain (- 0.25[- 0.37, - 0.14]), spasticity (- 0.36[CI - 0.54, - 0.19]), sleep (- 0.24[CI - 0.35, - 0.14]) and SUDs (- 0.48[CI - 0.92, - 0.04]). All other significant therapeutic effects have either low, very low, or even no grade of evidence. Cannabinoids produce different adverse events, and there is low to moderate grade of evidence for this conclusion depending on the type of cannabinoid.

CONCLUSIONS

Cannabinoids are effective therapeutics for several medical indications if their specific pharmacological properties are considered. We suggest that future systematic studies in the cannabinoid field should be based upon their specific pharmacology.

Cannabis-Based Products for Chronic Pain : A Systematic Review

BACKGROUND

Contemporary data are needed about the utility of cannabinoids in chronic pain.

PURPOSE

To evaluate the benefits and harms of cannabinoids for chronic pain.

DATA SOURCES

Ovid MEDLINE, PsycINFO, EMBASE, the Cochrane Library, and Scopus to January 2022.

STUDY SELECTION

English-language, randomized, placebo-controlled trials and cohort studies (≥1 month duration) of cannabinoids for chronic pain.

DATA EXTRACTION

Data abstraction, risk of bias, and strength of evidence assessments were dually reviewed. Cannabinoids were categorized by THC-to-CBD ratio (high, comparable, or low) and source (synthetic, extract or purified, or whole plant).

DATA SYNTHESIS

Eighteen randomized, placebo-controlled trials (n = 1740) and 7 cohort studies (n = 13 095) assessed cannabinoids. Studies were primarily short term (1 to 6 months); 56% enrolled patients with neuropathic pain, with 3% to 89% female patients. Synthetic products with high THC-to-CBD ratios (>98% THC) may be associated with moderate improvement in pain severity and response (≥30% improvement) and an increased risk for sedation and are probably associated with a large increased risk for dizziness. Extracted products with high THC-to-CBD ratios (range, 3:1 to 47:1) may be associated with large increased risk for study withdrawal due to adverse events and dizziness. Sublingual spray with comparable THC-to-CBD ratio (1.1:1) probably is associated with small improvement in pain severity and overall function and may be associated with large increased risk for dizziness and sedation and moderate increased risk for nausea. Evidence for other products and outcomes, including longer-term harms, were not reported or were insufficient.

LIMITATION

Variation in interventions; lack of study details, including unclear availability in the United States; and inadequate evidence for some products.

CONCLUSION

Oral, synthetic cannabis products with high THC-to-CBD ratios and sublingual, extracted cannabis products with comparable THC-to-CBD ratios may be associated with short-term improvements in chronic pain and increased risk for dizziness and sedation. Studies are needed on long-term outcomes and further evaluation of product formulation effects.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services. (PROSPERO: CRD42021229579).

Cannabis and cannabinoids for symptomatic treatment for people with multiple sclerosis

BACKGROUND

Spasticity and chronic neuropathic pain are common and serious symptoms in people with multiple sclerosis (MS). These symptoms increase with disease progression and lead to worsening disability, impaired activities of daily living and quality of life. Anti-spasticity medications and analgesics are of limited benefit or poorly tolerated. Cannabinoids may reduce spasticity and pain in people with MS. Demand for symptomatic treatment with cannabinoids is high. A thorough understanding of the current body of evidence regarding benefits and harms of these drugs is required.

OBJECTIVES

To assess benefit and harms of cannabinoids, including synthetic, or herbal and plant-derived cannabinoids, for reducing symptoms for adults with MS.

SEARCH METHODS

We searched the following databases from inception to December 2021: MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library), CINAHL (EBSCO host), LILACS, the Physiotherapy Evidence Database (PEDro), the World Health Organisation International Clinical Trials Registry Platform, the US National Institutes of Health clinical trial register, the European Union Clinical Trials Register, the International Association for Cannabinoid Medicines databank. We hand searched citation lists of included studies and relevant reviews.

SELECTION CRITERIA

We included randomised parallel or cross-over trials (RCTs) evaluating any cannabinoid (including herbal Cannabis, Cannabis flowers, plant-based cannabinoids, or synthetic cannabinoids) irrespective of dose, route, frequency, or duration of use for adults with MS.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. To assess bias in included studies, we used the Cochrane Risk of bias 2 tool for parallel RCTs and crossover trials. We rated the certainty of evidence using the GRADE approach for the following outcomes: reduction of 30% in the spasticity Numeric Rating Scale, pain relief of 50% or greater in the Numeric Rating Scale-Pain Intensity, much or very much improvement in the Patient Global Impression of Change (PGIC), Health-Related Quality of Life (HRQoL), withdrawals due to adverse events (AEs) (tolerability), serious adverse events (SAEs), nervous system disorders, psychiatric disorders, physical dependence.

MAIN RESULTS

We included 25 RCTs with 3763 participants of whom 2290 received cannabinoids. Age ranged from 18 to 60 years, and between 50% and 88% participants across the studies were female.  The included studies were 3 to 48 weeks long and compared nabiximols, an oromucosal spray with a plant derived equal (1:1) combination of tetrahydrocannabinol (THC) and cannabidiol (CBD) (13 studies), synthetic cannabinoids mimicking THC (7 studies), an oral THC extract of Cannabis sativa (2 studies), inhaled herbal Cannabis (1 study) against placebo. One study compared dronabinol, THC extract of Cannabis sativa and placebo, one compared inhaled herbal Cannabis, dronabinol and placebo. We identified eight ongoing studies. Critical outcomes • Spasticity: nabiximols probably increases the number of people who report an important reduction of perceived severity of spasticity compared with placebo (odds ratio (OR) 2.51, 95% confidence interval (CI) 1.56 to 4.04; 5 RCTs, 1143 participants; I2 = 67%; moderate-certainty evidence). The absolute effect was 216 more people (95% CI 99 more to 332 more) per 1000 reporting benefit with cannabinoids than with placebo. • Chronic neuropathic pain: we found only one small trial that measured the number of participants reporting substantial pain relief with a synthetic cannabinoid compared with placebo (OR 4.23, 95% CI 1.11 to 16.17; 1 study, 48 participants; very low-certainty evidence). We are uncertain whether cannabinoids reduce chronic neuropathic pain intensity. • Treatment discontinuation due to AEs: cannabinoids may increase slightly the number of participants who discontinue treatment compared with placebo (OR 2.41, 95% CI 1.51 to 3.84; 21 studies, 3110 participants; I² = 17%; low-certainty evidence); the absolute effect is 39 more people (95% CI 15 more to 76 more) per 1000 people. Important outcomes • PGIC: cannabinoids probably increase the number of people who report 'very much' or 'much' improvement in health status compared with placebo (OR 1.80, 95% CI 1.37 to 2.36; 8 studies, 1215 participants; I² = 0%; moderate-certainty evidence). The absolute effect is 113 more people (95% CI 57 more to 175 more) per 1000 people reporting improvement. • HRQoL: cannabinoids may have little to no effect on HRQoL (SMD -0.08, 95% CI -0.17 to 0.02; 8 studies, 1942 participants; I2 = 0%; low-certainty evidence); • SAEs: cannabinoids may result in little to no difference in the number of participants who have SAEs compared with placebo (OR 1.38, 95% CI 0.96 to 1.99; 20 studies, 3124 participants; I² = 0%; low-certainty evidence); • AEs of the nervous system: cannabinoids may increase nervous system disorders compared with placebo (OR 2.61, 95% CI 1.53 to 4.44; 7 studies, 1154 participants; I² = 63%; low-certainty evidence); • Psychiatric disorders: cannabinoids may increase psychiatric disorders compared with placebo (OR 1.94, 95% CI 1.31 to 2.88; 6 studies, 1122 participants; I² = 0%; low-certainty evidence); • Drug tolerance: the evidence is very uncertain about the effect of cannabinoids on drug tolerance (OR 3.07, 95% CI 0.12 to 75.95; 2 studies, 458 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Compared with placebo, nabiximols probably reduces the severity of spasticity in the short-term in people with MS. We are uncertain about the effect on chronic neurological pain and health-related quality of life. Cannabinoids may increase slightly treatment discontinuation due to AEs, nervous system and psychiatric disorders compared with placebo. We are uncertain about the effect on drug tolerance. The overall certainty of evidence is limited by short-term duration of the included studies.

The Efficacy of Cannabis on Multiple Sclerosis-Related Symptoms

Multiple sclerosis (MS) is known as an autoimmune disease that damages the neurons in the central nervous system. MS is characterized by its most common symptoms of spasticity, muscle spasms, neuropathic pain, tremors, bladder dysfunction, dysarthria, and some intellectual problems, including memory disturbances. Several clinical studies have been conducted to investigate the effects of cannabis on the relief of these symptoms in MS patients. The efficacy of Cannabis sativa (C. Sativa) in the management of MS outcomes such as spasticity, pain, tremors, ataxia, bladder functions, sleep, quality of life, and adverse effects were assessed in this review. Most clinical studies showed the positive effects of cannabinoids with their different routes of administration, such as oromucosal spray and oral form, in reducing most MS symptoms. The oromucosal spray Nabiximols demonstrated an improvement in reducing MS spasticity, pain, and quality of life with a tolerated adverse effect. Oral cannabinoids are significantly effective for treating MS pain and spasticity, while the other symptoms indicate slight improvement and the evidence is quite inconsistent. Oromucosal spray and oral cannabis are mainly used for treating patients with MS and have positive effects on treating the most common symptoms of MS, such as pain and spasticity, whereas the other MS symptoms indicated slight improvement, for which further studies are needed.

Central Neuropathic Pain Syndromes: Current and Emerging Pharmacological Strategies

Central neuropathic pain is caused by a disease or lesion of the brain or spinal cord. It is difficult to predict which patients will develop central pain syndromes after a central nervous system injury, but depending on the etiology, lifetime prevalence may be greater than 50%. The resulting pain is often highly distressing and difficult to treat, with no specific treatment guidelines currently available. This narrative review discusses mechanisms contributing to central neuropathic pain, and focuses on pharmacological approaches for managing common central neuropathic pain conditions such as central post-stroke pain, spinal cord injury-related pain, and multiple sclerosis-related neuropathic pain. Tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors, and gabapentinoids have some evidence for efficacy in central neuropathic pain. Medications from other pharmacologic classes may also provide pain relief, but current evidence is limited. Certain non-pharmacologic approaches, neuromodulation in particular, may be helpful in refractory cases. Emerging data suggest that modulating the primary afferent input may open new horizons for the treatment of central neuropathic pain. For most patients, effective treatment will likely require a multimodal therapy approach.

Sex-Dependent Prescription Patterns and Clinical Outcomes Associated With the Use of Two Oral Cannabis Formulations in the Multimodal Management of Chronic Pain Patients in Colombia

To date, the therapeutic use of cannabinoids in chronic pain management remains controversial owing to the limited clinical evidence found in randomized clinical trials (RCTs), the heterogeneous nature of the clinical indication, and the broad range of cannabis-based medicinal products (CBMPs) used in both experimental and observational clinical studies. Here we evaluate patient-reported clinical outcomes (PROMS) in a cohort of adult patients, diagnosed with chronic pain of diverse etiology, who received adjuvant treatment with oral, cannabis-based, magistral formulations between May and September 2021 at the Latin American Institute of Neurology and Nervous System (ILANS-Zerenia) in Bogotá, Colombia. During this period, 2,112 patients completed a PROMS questionnaire aimed at capturing the degree of clinical improvement of their primary symptom and any potential side effects. Most participants were female (76.1%) with an average age of 58.7 years old, and 92.5% (1,955 patients) reported some improvement in their primary symptom (p < 0.001). Two monovarietal, full-spectrum, cannabis formulations containing either cannabidiol (CBD 30 mg/mL; THC <2 mg/mL) or a balanced composition (THC 12 mg/mL; CBD 14 mg/mL) accounted for more than 99% of all prescriptions (59.5 and 39.8%, respectively). The degree of improvement was similar between both formulations, although males reported less effectiveness in the first 4 weeks of treatment. Sex-specific differences were also found in prescription patterns, with male patients increasing the intake of the balanced chemotype overtime. For many patients (71.7%) there were no adverse side effects associated to the treatment and those most reported were mild, such as somnolence (13.0%), dizziness (8.1%) and dry mouth (4.2%), which also appeared to fade over time. Our results constitute the first real-world evidence on the clinical use of medicinal cannabis in Colombia and suggest that cannabis-based oral magistral formulations represent a safe and efficacious adjuvant therapeutic option in the management of chronic pain.

Cannabinoids: Therapeutic Use in Clinical Practice

Medical case reports suggest that cannabinoids extracted from Cannabis sativa have therapeutic effects; however, the therapeutic employment is limited due to the psychotropic effect of its major component, Δ9-tetrahydrocannabinol (THC). The new scientific discoveries related to the endocannabinoid system, including new receptors, ligands, and mediators, allowed the development of new therapeutic targets for the treatment of several pathological disorders minimizing the undesirable psychotropic effects of some constituents of this plant. Today, FDA-approved drugs, such as nabiximols (a mixture of THC and non-psychoactive cannabidiol (CBD)), are employed in alleviating pain and spasticity in multiple sclerosis. Dronabinol and nabilone are used for the treatment of chemotherapy-induced nausea and vomiting in cancer patients. Dronabinol was approved for the treatment of anorexia in patients with AIDS (acquired immune deficiency syndrome). In this review, we highlighted the potential therapeutic efficacy of natural and synthetic cannabinoids and their clinical relevance in cancer, neurodegenerative and dermatological diseases, and viral infections.

Neurological Benefits, Clinical Challenges, and Neuropathologic Promise of Medical Marijuana: A Systematic Review of Cannabinoid Effects in Multiple Sclerosis and Experimental Models of Demyelination

Despite current therapeutic strategies for immunomodulation and relief of symptoms in multiple sclerosis (MS), remyelination falls short due to dynamic neuropathologic deterioration and relapses, leading to accrual of disability and associated patient dissatisfaction. The potential of cannabinoids includes add-on immunosuppressive, analgesic, neuroprotective, and remyelinative effects. This study evaluates the efficacy of medical marijuana in MS and its experimental animal models. A systematic review was conducted by a literature search through PubMed, ProQuest, and EBSCO electronic databases for studies reported since 2007 on the use of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) in MS and in experimental autoimmune encephalomyelitis (EAE), Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), and toxin-induced demyelination models. Study selection and data extraction were performed by 3 reviewers, and 28 studies were selected for inclusion. The certainty of evidence was appraised using the Cochrane GRADE approach. In clinical studies, there was low- and moderate-quality evidence that treatment with ~1:1 CBD/THC mixtures as a nabiximols (Sativex®) oromucosal spray reduced numerical rating scale (NRS) scores for spasticity, pain, and sleep disturbance, diminished bladder overactivity, and decreased proinflammatory cytokine and transcription factor expression levels. Preclinical studies demonstrated decreases in disease severity, hindlimb stiffness, motor function, neuroinflammation, and demyelination. Other experimental systems showed the capacity of cannabinoids to promote remyelination in vitro and by electron microscopy. Modest short-term benefits were realized in MS responders to adjunctive therapy with CBD/THC mixtures. Future studies are recommended to investigate the cellular and molecular mechanisms of cannabinoid effects on MS lesions and to evaluate whether medical marijuana can accelerate remyelination and retard the accrual of disability over the long term.

“The Two Sides of the Same Coin”—Medical Cannabis, Cannabinoids and Immunity: Pros and Cons Explained

Cannabis, as a natural medicinal remedy, has long been used for palliative treatment to alleviate the side effects caused by diseases. Cannabis-based products isolated from plant extracts exhibit potent immunoregulatory properties, reducing chronic inflammatory processes and providing much needed pain relief. They are a proven effective solution for treatment-based side effects, easing the resulting symptoms of the disease. However, we discuss the fact that cannabis use may promote the progression of a range of malignancies, interfere with anti-cancer immunotherapy, or increase susceptibility to viral infections and transmission. Most cannabis preparations or isolated active components cause an overall potent immunosuppressive impact among users, posing a considerable hazard to patients with suppressed or compromised immune systems. In this review, current knowledge and perceptions of cannabis or cannabinoids and their impact on various immune-system components will be discussed as the “two sides of the same coin” or “double-edged sword”, referring to something that can have both favorable and unfavorable consequences. We propose that much is still unknown about adverse reactions to its use, and its integration with medical treatment should be conducted cautiously with consideration of the individual patient, effector cells, microenvironment, and the immune system.

Dorsal Column Stimulation and Cannabinoids in the Treatment of Chronic Nociceptive and Neuropathic Pain: a Review of the Clinical and Pre-clinical Data

PURPOSE OF REVIEW

The main objective of this review is to appraise the literature on the role of spinal cord stimulation (SCS), cannabinoid therapy, as well as SCS and cannabinoid combination therapy for the management of chronic neuropathic and nociceptive pain. Current research suggests that SCS reduces pain and increases functional status in carefully selected patients with minimal side effects.

RECENT FINDINGS

As cannabinoid-based medications become a topic of increasing interest in pain management, data remains limited regarding the clinical efficacy of cannabinoids for pain relief. Furthermore, from a mechanistic perspective, although various pain treatment modalities utilize overlapping pain-signaling pathways, clarifying whether cannabinoids work synergistically with SCS via shared mechanisms remains to be determined. In considering secondary outcomes, the current literature suggests cannabinoids improve quality of life, specifically sleep quality, and that SCS decreases opioid consumption, increases functional capacity, and decreases long-term healthcare costs. These findings, along with the high safety profiles of SCS and cannabinoids overall, incentivize further exploration of cannabinoids as an adjunctive therapy to SCS in the treatment of neuropathic and nociceptive pain.

Comparison of the Effectiveness and Tolerability of Nabiximols (THC:CBD) Oromucosal Spray versus Oral Dronabinol (THC) as Add-on Treatment for Severe Neuropathic Pain in Real-World Clinical Practice: Retrospective Analysis of the German Pain e-Registry

Purpose

To compare the effectiveness and tolerability of add-on treatment with nabiximols (NBX: delta-9-tetrahydrocannabinol: cannabidiol) oromucosal spray or oral dronabinol (DRO: synthetic tetrahydrocannabinol) in patients with severe neuropathic pain poorly responsive to established treatments.

Methods

An analysis was conducted of anonymized, propensity score-matched real-world data from the German Pain e-Registry, using a sequential non-inferiority superiority approach, for adult outpatients with neuropathic pain who had initiated treatment with NBX or DRO between 10 March 2017 and 31 December 2019. The primary effectiveness variable was percent change from baseline in a 9-factor aggregated symptom relief (ASR-9) score, a composite index of nine distinct pain- and health-related parameters assessed using validated patient-reported instruments. Safety was assessed by the incidence of physician-confirmed treatment-related adverse events (TRAEs), and TRAEs leading to discontinuation.

Results

Propensity score-matched data were analyzed for 337 patients treated with NBX and 337 patients treated with DRO. Mean (standard deviation) THC dose over the 24-week evaluation period was 16.6 (6.5) mg for NBX and 17.2 (7.6) mg for DRO (p<0.001). Median (standard error) improvement relative to baseline in the ASR-9 composite score was 55.4% (0.5) for NBX and 40.5% (0.5) for DRO (least squares mean difference, 14.0 (0.7), 95% confidence interval 12.6–15.4; p<0.001), and incidences of TRAEs (21.1 vs 35%) and TRAE-related discontinuations (5.9 vs 14.8%) were significantly lower with NBX than DRO (p<0.001 for both), collectively indicating pre-specified non-inferiority and superiority of NBX. More NBX- than DRO-treated patients discontinued non-cannabinoid background pain medications and rescue analgesics, especially opioid analgesics (p<0.001 for both).

Conclusion

Add-on treatment with cannabinoids is effective for treatment of severe neuropathic pain with inadequate response to established treatments. In daily practice, NBX had superior effectiveness and tolerability compared to DRO. The results emphasize the importance of combining CBD with THC in this patient population.

Cannabinoid Therapeutics in Chronic Neuropathic Pain: From Animal Research to Human Treatment

Despite the importance of pain as a warning physiological system, chronic neuropathic pain is frequently caused by damage in the nervous system, followed by persistence over a long period, even in the absence of dangerous stimuli or after healing of injuries. Chronic neuropathic pain affects hundreds of millions of adults worldwide, creating a direct impact on quality of life. This pathology has been extensively characterized concerning its cellular and molecular mechanisms, and the endocannabinoid system (eCS) is widely recognized as pivotal in the development of chronic neuropathic pain. Scientific evidence has supported that phyto-, synthetic and endocannabinoids are efficient for pain management, while strong data arise from the therapeutic use of Cannabis-derived products. The use of medicinal Cannabis products is directed toward not only relieving symptoms of chronic pain, but also improving several aspects of patients’ welfare. Here, we review the involvement of eCS, along with other cellular and molecular elements, in chronic neuropathic pain pathology and how this system can be targeted for pain management.

Dose-Related Inhibition of Capsaicin Responses by Cannabinoids CBG, CBD, THC and their Combination in Cultured Sensory Neurons

BACKGROUND

The analgesic effects of Cannabis sativa are mediated by ∆9 tetrahydrocannabinol (THC), but the contributions of other bioactive complex components, including cannabigerol (CBG) and cannabidiol (CBD), are unclear. We describe the individual and combined effects of CBG, CBD and THC, on blocking capsaicin responses in dorsal root ganglion (DRG) neurons, in an in vitro model of nociceptor hypersensitivity.

MATERIALS AND METHODS

Adult rat DRG were dissected and enzyme digested to obtain a neuronal suspension in BSF2 medium containing 2% fetal calf serum, and the neurotrophic factors NGF and GDNF. After 48 h, cultured neurons were loaded with Fura-2 AM, to determine the effects of cannabinoids on capsaicin responses using calcium imaging. In control experiments, neurons were treated with vehicle, followed by 1 µM capsaicin. In cannabinoid treated cultures, CBG, CBD or THC were applied individually, or combined (1:1:1 ratio), followed by 1 µM capsaicin. Data from n = 6 experiments were analysed with Student's t-test and Pearson's correlation coefficient.

RESULTS

CBG, CBD and THC, applied individually, elicited dose-related calcium influx in a subset of DRG neurons, and a corresponding dose-related reduction of subsequent responses to capsaicin. Maximum inhibition of capsaicin responses was observed at 30 µM CBG, 100 µM CBD, and 100 µM THC individually, and with combined CBD+CBG+THC (1:1:1) at 90 µM. THC+CBD+CBG combined in a 1:1:1 proportion has the potential to enhance the potency of these compounds applied individually. There was a high correlation between cannabinoid-mediated calcium influx and reduction of capsaicin responses: CBG = -0.88, THC = -0.97, CBD = -0.99 and combined CBG + THC + CBD = -1.00.

CONCLUSION

CBG, CBD and THC demonstrated potent dose-related inhibition of capsaicin responses in DRG neurons when applied individually in vitro, and enhanced when applied in combination, being most effective at 90 μM. Thus, efficacy and tolerability of THC could be improved in combination with CBG and CBD at optimal concentrations, which deserve further studies in vivo.

Medical Cannabis and Cannabinoids for Impaired Sleep: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

STUDY OBJECTIVES

We conducted a systematic review to explore the effectiveness of medical cannabis for impaired sleep.

METHODS

We searched MEDLINE, EMBASE, CENTRAL and PsychINFO to January 2021 for randomized trials of medical cannabis or cannabinoids for impaired sleep vs. any non-cannabis control. When possible, we pooled effect estimates for all patient-important sleep-related outcomes and used the GRADE approach to appraise the certainty of evidence.

RESULTS

Thirty-nine trials (5,100 patients) were eligible for review, of which 38 evaluated oral cannabinoids and 1 administered inhaled cannabis. The median follow-up was 35 days, and most trials (33 of 39) enrolled patients living with chronic cancer or noncancer chronic pain. Among patients with chronic pain, moderate certainty evidence found that medical cannabis probably results in a small improvement in sleep quality versus placebo (modeled risk difference [RD] for achieving the minimally important difference [MID], 8% [95% CI, 3 to 12]). Moderate to high certainty evidence shows that medical cannabis vs. placebo results in a small improvement in sleep disturbance for chronic non-cancer pain (modeled RD for achieving the MID, 19% [95% CI, 11 to 28]) and a very small improvement in sleep disturbance for chronic cancer pain (WMD of -0.19cm [95%CI, -0.36 to -0.03cm]; interaction p=0.03). Moderate to high certainty evidence shows medical cannabis, versus placebo, results in a substantial increase in the risk of dizziness (RD 29% [95%CI, 16 to 50], for trials with ≥3 months follow-up), and a small increase in the risk of somnolence, dry mouth, fatigue, and nausea (RDs ranged from 6% to 10%).

CONCLUSION

Medical cannabis and cannabinoids may improve impaired sleep among people living with chronic pain, but the magnitude of benefit is likely small.