Medical Marijuana and Chronic Pain: a Review of Basic Science and Clinical Evidence

Legalization of Smokable Medical Cannabis and Changes in the Dispensed Amount of Δ-9 Tetrahydrocannabinol Per Patient

Introduction: Florida's medical cannabis (marijuana) program is among the largest in the United States. Smokable cannabis forms were not legally available in this program until 2019, and five years after other forms of cannabis were available. This study assessed changes in Δ-9 tetrahydrocannabinol (THC) dispensed per patient following legalization of smokable cannabis in Florida. Materials and Methods: This quasi-experimental study used data from the Florida Department of Health Office of Medical Marijuana Use Reports on THC dispensing from April 6, 2018, through March 13, 2020. Certified medical cannabis user during the study period was included. The exposure was the dispensed amount of THC from legalized smokable forms of medical cannabis (statute identified as SB182), effective as of March 2019. Changes in level and trend of average milligram (mg) of dispensed THC per certified patient with 95% confidence intervals (CIs), before and after SB182, were calculated by fitting a generalized least squares linear model and allowing a 17-week phase-in period. Results: The number of certified patients increased by 24.8% from 197,107 (March 22, 2019) to 246,079 (July 19, 2019) and to 325,868 by March 13, 2020. Assuming that a 20% THC concentration in smokable products, there was a significant level increase in the mean weekly dispensed THC amount per certified patient of 138.45 mg (95% CI: 102.69-174.20), translating to a 42.18% increase (95% CI: 33.14-50.28), from the pre-policy period. We noted a continuous increase of 5.62 mg per certified patient per week (95% CI: 4.35-6.89) throughout the 35 weeks following the policy, when compared with the period before. Assuming 10% THC concentration in smokable products, we observed a significant level increase of 35.10 mg (95% CI: 5.31-64.88), corresponding to an increase of 10.70% (95% CI: 1.70-18.89), and a trend increase of 2.23 mg per certified patient per week (95% CI: 1.18-3.29). Discussion: The expansion of the Florida medical cannabis program to include smokable cannabis forms was associated with a significant increase in the mean amount of weekly dispensed THC per certified patient. Findings suggest that the dispensed amount of THC after legalization of smokable medical cannabis far exceeds the maximum recommended daily dose, based on extrapolation from oral cannabis product dosing recommendations from one expert consensus statement, raising questions about the safety, and need for consumer education.

Effect of organic biostimulants on cannabis productivity and soil microbial activity under outdoor conditions

In 2019 and 2020, we investigated the individual and combined effects of two biofertilizers (manure tea and bioinoculant) and one humic acid (HA) product on cannabis biochemical and physiological parameters and soil CO2 evolution under outdoor conditions. Our hypothesis was that HA would increase the microbial activity in the biofertilizers and synergy of both compounds would promote better plant performance and stimulate soil microbial activity. In 2020, the individual and combined application of biofertilizers and HA increased cannabis height, chlorophyll content, photosynthetic efficiency, aboveground biomass, and bucked biomass by 105, 52, 43, 122, and 117%, respectively. Impacts were greater under suboptimal growing conditions caused by planting delay experienced in 2020. In 2019, planting date occurred in-between the most favorable period and chlorophyll content and photosynthetic efficiency were the only parameters influenced by the application of biostimulants. The discrepancies between the two growing seasons reinforce the evidence of other studies that biostimulants efficacy is maximized under stress conditions. This study could not conclusively confirm that the combined use of biofertilizer + HA is a superior practice since affected plant parameters did not differ from application of the compounds singly. Similarly, only one biofertilizer + HA treatment increased soil microbial activity. More research is needed to define optimum rates and combinations of biofertilizer and stimulants for cannabis.

The Effect of Preoperative Marijuana Use on Surgical Outcomes, Patient-Reported Outcomes, and Opioid Consumption Following Lumbar Fusion

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To (1) investigate the effect of marijuana use on surgical outcomes following lumbar fusion, (2) determine how marijuana use affects patient-reported outcomes measures (PROMs), and (3) determine if marijuana use impacts the quantity of opioids prescribed.

METHODS

Patients > 18 years of age who underwent primary one- or two-level lumbar fusion with preoperative marijuana use at our institution were identified. A 3:1 propensity match incorporating patient demographics and procedure type was conducted to compare preoperative marijuana users to non-marijuana users. Patient demographics, surgical characteristics, surgical outcomes (90-day all-cause and 90-day surgical readmissions, reoperations, and revision surgeries), pre- and postoperative narcotic usage, and PROMs were compared between groups. Multivariate regression models were created to determine the effect of marijuana on surgical reoperations patient-reported outcomes (PROMs) 1-year postoperatively.

RESULTS

Of the 259 included patients, 65 used marijuana preoperatively. Multivariate logistic regression analysis demonstrated that marijuana use (OR = 2.28, P = .041) significantly increased the likelihood of having a spine reoperation. No other surgical outcome was found to be significantly different between groups. Multivariate linear regression analysis showed that marijuana use was not significantly associated with changes in 1-year postoperative PROMs (all, P > .05). The quantity of pre- and postoperative opioids prescriptions was not significantly different between groups (all, P > .05).

CONCLUSIONS

Preoperative marijuana use increased the likelihood of a spine reoperation for any indication following lumbar fusion, but it was not associated with 90-day all cause readmission, surgical readmission, the magnitude of improvement in PROMs, or differences in opioid consumption.

LEVEL OF EVIDENCE

III.

Applications of Cannabinoids in Neuropathic Pain: An Updated Review

Neuropathic pain is experienced due to injury to the nerves, underlying disease conditions or toxicity induced by chemotherapeutics. Multiple factors can contribute to neuropathic pain such as central nervous system (CNS)-related autoimmune and metabolic disorders, nerve injury, multiple sclerosis and diabetes. Hence, development of pharmacological interventions to reduce the drawbacks of existing chemotherapeutics and counter neuropathic pain is an urgent unmet clinical need. Cannabinoid treatment has been reported to be beneficial for several disease conditions including neuropathic pain. Cannabinoids act by inhibiting the release of neurotransmitters from presynaptic nerve endings, modulating the excitation of postsynaptic neurons, activating descending inhibitory pain pathways, reducing neural inflammation and oxidative stress and also correcting autophagy defects. This review provides insights on the various preclinical and clinical therapeutic applications of cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN) in various diseases and the ongoing clinical trials for the treatment of chronic and acute pain with cannabinoids. Pharmacological and genetic experimental strategies have well demonstrated the potential neuroprotective effects of cannabinoids and also elaborated their mechanism of action for the therapy of neuropathic pain.

Medical Cannabis for Chronic Nonmalignant Pain Management

PURPOSE OF REVIEW

Cannabis has been used since ancient times for medical and recreational research. This review article will document the validity of how medical cannabis can be utilized for chronic nonmalignant pain management.

RECENT FINDINGS

Current cannabis research has shown that medical cannabis is indicated for symptom management for many conditions not limited to cancer, chronic pain, headaches, migraines, and psychological disorders (anxiety and post-traumatic stress disorder). Δ9-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are active ingredients in cannabis that modulate a patient's symptoms. These compounds work to decrease nociception and symptom frequency via the endocannabinoid system. Research regarding pain management is limited within the USA as the Drug Enforcement Agency (DEA) classifies it as a schedule one drug. Few studies have found a limited relationship between chronic pain and medical cannabis use. A total of 77 articles were selected after a thorough screening process using PubMed and Google Scholar. This paper demonstrates that medical cannabis use provides adequate pain management. Patients suffering from chronic nonmalignant pain may benefit from medical cannabis due to its convenience and efficacy.

Impact of cannabinoids on pregnancy, reproductive health and offspring outcomes

Cannabis is the most commonly used federally illegal drug in the United States and world, especially among people of reproductive age. In addition, the potency of cannabis products has increased significantly in the past decade. This is concerning because the available evidence suggests an adverse effect from cannabis exposure on male and female reproductive health. Exposure to cannabinoids may have differential impacts on female reproductive health across a woman's lifespan, from preconception to pregnancy, throughout lactation, and during menopause. Even more, cannabis use has been associated an adverse effect on fetal outcomes, and longer-term offspring health and developmental trajectories. Despite the prevalence of cannabis use, there is limited available evidence regarding its safety, especially in regard to reproductive health, pregnancy and lactation. The biological effects of cannabis are mediated by the endocannabinoid system and studies have reported the presence of cannabinoid receptors in the male and female reproductive tract, on sperm and the placenta, suggesting the endocannabinoid system plays a role in regulating reproduction. Cannabis use can impact male and female fertility and has been associated with altered reproductive hormones, menstrual cyclicity and semen parameters. Use of cannabis in males has also been associated with erectile dysfunction, abnormal spermatogenesis, and testicular atrophy. In females, cannabis use has been associated with infertility and abnormal embryo implantation and development. The main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), can also cross the placenta and has been detected in breastmilk. Maternal cannabis use during pregnancy and lactation has been associated with adverse effects including small for gestational age infants, preterm birth, fetal neurodevelopmental consequences, and impaired offspring sociobehavioral and cognitive development. The prevalence of cannabis use to alleviate menopausal symptoms has also increased despite the limited information on its benefits and safety. As cannabis use is on the rise, it is critical to understand its impact on reproductive health and offspring developmental outcomes. This is an understudied, but timely subject, with much needed information to guide healthcare providers and those interested in conceiving, or that are pregnant and lactating, as well as those at the end of their reproductive time span.

A Systematic Review on Cannabinoids for Neuropathic Pain Administered by Routes Other than Oral or Inhalation

The use of cannabis and cannabinoid products for the treatment of neuropathic pain is a growing area of research. This type of pain has a high prevalence, limited response to available therapies and high social and economic costs. Systemic cannabinoid-based therapies have shown some unwanted side effects. Alternative routes of administration in the treatment of neuropathic pain may provide better acceptance for the treatment of multiple pathologies associated with neuropathic pain. To examine the efficacy, tolerability, and safety of cannabinoids (individualized formulations, phytocannabinoids, and synthetics) administered by routes other than oral or inhalation compared to placebo and/or conventional medications in the management of neuropathic pain. This systematic review of the literature reveals a lack of clinical research investigating cannabis by routes other than oral and inhalation as a potential treatment for neuropathic pain and highlights the need for further investigation with well-designed clinical trials. There is a significant lack of evidence indicating that cannabinoids administered by routes other than oral or inhaled may be an effective alternative, with better tolerance and safety in the treatment of neuropathic pain. Higher quality, long-term, randomized controlled trials are needed to examine whether cannabinoids administered by routes other than inhalation and oral routes may have a role in the treatment of neuropathic pain.

"The Drug Use Unfortunately isn't all Bad": Chronic Disease Self-Management Complexity and Strategy Among Marginalized People Who Use Drugs

Self-management programs improve health outcomes and self-management is recommended for chronic conditions. Yet chronic disease self-management supports have rarely been applied to people who use drugs (PWUD). Thus, our objective was to explore self-management experiences among marginalized PWUD. We used community-based participatory methods and conducted qualitative interviews. Participants self-identified as having long-term and past year experience using non-prescribed drugs, one other chronic condition, and socioeconomic marginalization. We analyzed the data using reflexive thematic analysis. Although many participants considered drug use a chronic health issue, self-medicating with non-prescribed drugs was also a key self-management strategy to address other health issues. Participants also described numerous other strategies, including cognitive and behavioral tactics. These findings highlight the need for a safe supply of pharmaceutical-grade drugs to support self-management among marginalized PWUD. Self-management supports should also be tailored to address relevant topics (e.g., harm reduction, withdrawal), include creative activities, and not hinder PWUD's agency.

The Lived Experience of Managing HIV and Chronic Pain: Qualitative Interviews with Patients and Healthcare Providers

People living with HIV (PLWH) experience higher rates of comorbid chronic pain conditions compared to the general population. Managing HIV and chronic pain, two stigmatized health conditions, can exacerbate physical and psychological suffering. The current qualitative study was designed to increase our understanding of the experience of living with HIV and chronic pain. Twenty participants were recruited from a hospital-based immunology center to participate in individual in-depth qualitative interviews. The interviews focused on the experience of living with (or managing) chronic pain for PLWH. All interviews were audio recorded, transcribed and double-coded. Several themes emerged from our applied thematic analysis of the transcripts. The primary theme was that pain remained poorly managed among PLWH. Patients engaged in a variety of pain management strategies and described benefits from both traditional pain management interventions (e.g., pharmacology, physical therapy) as well as non-traditional approaches (e.g., medical marijuana, cannabidiol products, and spirituality). Other themes that emerged included barriers related to health insurance and the need to validate the patient pain experience. PLWH and chronic pain described compounding effects of managing two chronic health conditions, including perceived immune system over-activation, heightened awareness of illness, and negative mindset. More research is needed to improve care for those managing these often co-occurring health conditions.

Prevalence and self-reported reasons of cannabis use for medical purposes in USA and Canada

RATIONALE

There has been increasing attention on cannabis use for medical purposes, but there is currently a lack of data on its epidemiology.

OBJECTIVES

To examine the epidemiology of self-reported cannabis use for medical purposes by (1) estimating its prevalence, (2) comparing gender and age differences, and (3) investigating what reasons they were used to manage.

METHODS

Participants included 27,169 respondents (aged 16-65) who completed Wave 1 of The International Cannabis Policy Study (ICPS) conducted across Canada and the USA in 2018 via online surveys. Cannabis policy conditions were "US legal-recreational" (legal for both recreational and medical uses), "US legal-medical only", "US illegal", and "Canada-medical only".

RESULTS

The overall prevalence of self-reported ever cannabis use for medical purposes was 27%, with similar rates by sex and the highest prevalence in young adults. Prevalence was higher in US legal-recreational states (34%) than US illegal states (23%), US legal-medical only states (25%), and Canada (25%). The most common physical health reasons include use to manage pain (53%), sleep (46%), headaches/migraines (35%), appetite (22%), and nausea/vomiting (21%). For mental health reasons, the most common were for anxiety (52%), depression (40%), and PTSD/trauma (17%). There were 11% who reported using cannabis for managing other drug or alcohol use and 4% for psychosis.

CONCLUSIONS

A substantial proportion of the North American population self-reported cannabis use for medical purposes for a variety of medical reasons, including those living in jurisdictions without legal markets. Further research is needed to understand the safety and efficacy of these forms of medical cannabis use.

Efficacy of cannabis-based medications compared to placebo for the treatment of chronic neuropathic pain: a systematic review with meta-analysis

Background

Chronic neuropathic pain (NP) presents therapeutic challenges. Interest in the use of cannabis-based medications has outpaced the knowledge of its efficacy and safety in treating NP. The objective of this review was to evaluate the effectiveness of cannabis-based medications in individuals with chronic NP.

Methods

Randomized placebo-controlled trials using tetrahydrocannabinol (THC), cannabidiol (CBD), cannabidivarin (CBDV), or synthetic cannabinoids for NP treatment were included. The MEDLINE, Cochrane Library, EMBASE, and Web of Science databases were examined. The primary outcome was the NP intensity. The risk of bias analysis was based on the Cochrane handbook.

Results

The search of databases up to 2/1/2021 yielded 379 records with 17 RCTs included (861 patients with NP). Meta-analysis showed that there was a significant reduction in pain intensity for THC/CBD by -6.624 units (P < .001), THC by -8.681 units (P < .001), and dronabinol by -6.0 units (P = .008) compared to placebo on a 0-100 scale. CBD, CBDV, and CT-3 showed no significant differences. Patients taking THC/CBD were 1.756 times more likely to achieve a 30% reduction in pain (P = .008) and 1.422 times more likely to achieve a 50% reduction (P = .37) than placebo. Patients receiving THC had a 21% higher improvement in pain intensity (P = .005) and were 1.855 times more likely to achieve a 30% reduction in pain than placebo (P < .001).

Conclusion

Although THC and THC/CBD interventions provided a significant improvement in pain intensity and were more likely to provide a 30% reduction in pain, the evidence was of moderate-to-low quality. Further research is needed for CBD, dronabinol, CT-3, and CBDV.

Effects of marijuana on reproductive health: preconception and gestational effects

PURPOSE OF REVIEW

Recent widespread legalization changes have promoted the availability of marijuana and its increased potency and perceived safety. The limited evidence on reproductive and perinatal outcomes from marijuana exposure is enough to warrant concern and action. The objective of this review is to provide a current and relevant summary of the recent literature surrounding this topic.

RECENT FINDINGS

The available published studies on the effect of marijuana exposure on reproductive health and pregnancy outcomes are conflicting. Human studies are often observational or retrospective and confounded by self-report and polysubstance use. However, the current, limited evidence suggests that marijuana use adversely affects male and female reproductive health. Additionally, prenatal marijuana exposure has been reported to be associated with an increased risk of preterm birth and small for gestational age infants.

SUMMARY

With the increasing prevalence of marijuana use, there is an urgent need for evidence-driven recommendations and guidelines for couples interested in conception, affected by infertility or who are expecting. At this time, no amount of marijuana use during conception or pregnancy is known to be well tolerated and the limited available evidence suggests that the safest choice is to abstain.

Toxicological aspects of cannabinoid, pesticide and metal levels detected in light Cannabis inflorescences grown in Italy

Recently, the cultivation of light Cannabis, with a total THC content less than 0.6%, has been encouraged due to its industrial and therapeutic potential. This has increased the consumption of hemp for both smoking purposes and food preparation. Even so, Cannabis inflorescences are not subject to EU regulations and standards provided for food and tobacco products. A study was carried out on thirty-one inflorescences samples, collected in different Italian regions, in order to determine cannabinoids, pesticides and metals and to evaluate the exposure of consumers to contaminants and ensure a safe consumption. Contents of THC were always below 0.5%, while CBD ranged between 0.3 and 8.64%. The determination of 154 pesticides showed that 87% of the samples contained fungicides and insecticides in the range 0.01-185 μg/g. The most found are spinosad and cyprodinil. The concentration of metals ranged from 1 to more than 100 μg/g and As, Cd, Co, Cr, Hg, Cu, Mo, Ni and V exceeded the regulatory US limits for inhaled Cannabis products, while Pb exceeded them for both oral and inhaled products. These contaminants are intrinsically toxic and may affect public health. Actions are needed to establish regulatory measures and reduce the adverse effects caused by contaminants in Cannabis.

Cannabis and pain: a scoping review

For centuries, cannabis has been used with many different purposes, including medicinal use, usually bypassing any formal approval process. However, during the last decade, interest in cannabis in medicine has been increasing, and several countries, including the United States and Canada, have produced their own legislation about marihuana and cannabis-based medicines. Because of this, interest in research has been increasing and evidence about its medical effects is becoming necessary. We conducted a review examining the evidence of cannabis in pain. Cannabis had been shown to be useful in acute and chronic pain, however recently, these results have been controverted. Within the different types of chronic pain, it has a weak evidence for neuropathic, rheumatic pain, and headache, modest evidence for multiple sclerosis related pain, and as adjuvant therapy in cancer pain. There is no strong evidence to recommend cannabis in order to decrease opioids in patients with chronic use. Even though cannabis-based medications appear to be mostly safe, mild adverse effects are common; somnolence, sedation, amnesia, euphoric mood, hyperhidrosis, paranoia, and confusion may limit the use of cannabis in clinical practice. Risks have not been systematically analyzed. Special concern arises on how adverse effect might affect vulnerable population such as elderly patients. More research is needed in order to evaluate benefits and risks, as well as the ideal administration route and dosages. As cannabis use increases in several countries, answers to these questions might be coming soon.

Marie B, Milavetz G, Herr K. Cannabidiol (CBD) Use by Older Adults for Acute and Chronic Pain

Legalization of cannabidiol (CBD) products has ignited interest in clinical practice and research. One desired indication includes possible pain-relieving effects of CBD. The purposes of the current article are to (1) clarify terminology relevant to cannabinoids; (2) explain and understand the pharmacotherapeutics of CBD; (3) examine research of the current use of CBD by older adults for treating pain; (4) discuss safety considerations with using CBD products; and (5) provide best practice recommendations for clinicians as they advise their older adult patients. A review of the literature demonstrated mixed results on the efficacy of CBD in relieving pain in older adults. There is inconsistency in the labeling of over-the-counter CBD products that can result in safety issues and will require more federal quality control. Likewise, gaps in knowledge regarding safety and efficacy of CBD use in older adults are vast and require further research. [Journal of Gerontological Nursing, 47(7), 6-15.].

Fast liquid chromatography-tandem mass spectrometry method for the simultaneous determination of phytocannabinoids in oily based preparations

The reported method aims to be a powerful aid for the simultaneous determination of tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), and tetrahydrocannabivarin (THCV) in oily based preparations. The chromatographic separation was carried out using an Hypersil Gold PFP (50 × 2.1 mm, 1.9 μm) column, using H2O + 2 mM ammonium formate + 0.2 % formic acid (M1) and Methanol + 2 mM ammonium formate + 0.2 % formic acid (M2) as mobile phases. The flow rate was set 0.4 mL/min. Specifically, this method was validated in terms of linearity, limit of detections and quantifications (LODs and LOQs), accuracy (precision and trueness, both intra and interday), selectivity, and matrix effects. This procedure allowed quantifying seven phytocannabinoids in less than 10 min. The validated method shows a good linearity within the range 0.25-1000 ng/mL, while precision and trueness (intra- and inter-day) were below <13.25 % and 7.59 %, respectively. Regarding the matrix effect, the method satisfies all the requirements, except for the THC and THCV, where it reaches about 120 %. This element does not affect the method performances as it has been observed that this value is constant and reproducible and therefore does not involve errors in the quantitative analysis. The method was tested and applied on more 70 different oily based preparations. Furthermore, starting from four different cannabis cultivar (FM2, Bedrolite, Bedrocan, and Bediol), it allowed to evaluate the reproducibility of the magistrali preparations. The real samples, in fact, derive from different local pharmacies, and were analyzed by the accredited UNI CEI EN ISO/IEC 17025:2018, Pharmatoxicology Laboratory (ACCREDIA, lab n. 2274 ASLPE, accreditation number 1822 L), accordingly to the current regulations.

Studies of involvement of G-protein coupled receptor-3 in cannabidiol effects on inflammatory responses of mouse primary astrocytes and microglia

Cannabidiol (CBD) exhibits anti-inflammatory and neuroprotective properties and is suggested to be effective in the pre-clinical and clinical treatment of illnesses of the central nervous system (CNS). Two major types of CNS glial cells, astrocytes and microglia, play critical roles in the development and pathogenesis of CNS diseases. However, the mechanisms by which CBD plays an anti-inflammatory and neuroprotective role for these glial cells have not been fully elucidated. In this study, we examined the effects of CBD on the inflammatory response of mouse primary astrocytes and microglia. We also investigated whether the effect of CBD on cytokine release is mediated by the G protein coupled receptor 3 (GPR3), which was recently identified as a novel receptor for CBD. Our results showed that CBD inhibited inflammatory responses of astrocytes and microglia stimulated with lipopolysaccharide (LPS), a Toll-like receptor 4 (TLR4) ligand in vitro and in vivo. In addition, CBD reduced the phosphorylation of STAT3 and NF-κB signaling pathways in LPS-stimulated astrocytes. However, the inhibitory effect of CBD on pro-inflammatory cytokine production was independent of GPR3 expression in both types of glial cells. Thus, although CBD is effective in ameliorating the activation of astrocytes and microglia, its mechanism of action still requires further study. Our data support the concept that CBD may have therapeutic potential for neurological disorders that involve neuroinflammation.

Opioid use in medical cannabis authorization adult patients from 2013 to 2018: Alberta, Canada

BACKGROUND

The opioid overdose epidemic in Canada and the United States has become a public health crisis - with exponential increases in opioid-related morbidity and mortality. Recently, there has been an increasing body of evidence focusing on the opioid-sparing effects of medical cannabis use (reduction of opioid use and reliance), and medical cannabis as a potential alternative treatment for chronic pain. The objective of this study is to assess the effect of medical cannabis authorization on opioid use (oral morphine equivalent; OME) between 2013 and 2018 in Alberta, Canada.

METHODS

All adult patients defined as chronic opioid users who were authorized medical cannabis by their health care provider in Alberta, Canada from 2013 to 2018 were propensity score matched to non-authorized chronic opioid using controls. A total of 5373 medical cannabis patients were matched to controls, who were all chronic opioid users. The change in the weekly average OME of opioid drugs for medical cannabis patients relative to controls was measured. Interrupted time series (ITS) analyses was used to assess the trend change in OME during the 26 weeks (6 months) before and 52 weeks (1 year) after the authorization of medical cannabis among adult chronic opioid users.

RESULTS

Average age was 52 years and 54% were female. Patients on low dose opioids (< 50 OME) had an increase in their weekly OME per week (absolute increase of 112.1 OME, 95% CI: 104.1 to 120.3); whereas higher dose users (OME > 100), showed a significant decrease over 6 months (- 435.5, 95% CI: - 596.8 to - 274.2) compared to controls.

CONCLUSIONS

This short-term study found that medical cannabis authorization showed intermediate effects on opioid use, which was dependent on initial opioid use. Greater observations of changes in OME appear to be in those patients who were on a high dosage of opioids (OME > 100); however, continued surveillance of patients utilizing both opioids and medical cannabis is warranted by clinicians to understand the long-term potential benefits and any harms of ongoing use.

Sleep deficits and cannabis use behaviors: an analysis of shared genetics using linkage disequilibrium score regression and polygenic risk prediction

STUDY OBJECTIVES

Estimate the genetic relationship of cannabis use with sleep deficits and an eveningness chronotype.

METHODS

We used linkage disequilibrium score regression (LDSC) to analyze genetic correlations between sleep deficits and cannabis use behaviors. Secondly, we generated sleep deficit polygenic risk score (PRS) and estimated their ability to predict cannabis use behaviors using linear and logistic regression. Summary statistics came from existing genome-wide association studies of European ancestry that were focused on sleep duration, insomnia, chronotype, lifetime cannabis use, and cannabis use disorder (CUD). A target sample for PRS prediction consisted of high-risk participants and participants from twin/family community-based studies (European ancestry; n = 760, male = 64%; mean age = 26.78 years). Target data consisted of self-reported sleep (sleep duration, feeling tired, and taking naps) and cannabis use behaviors (lifetime ever use, number of lifetime uses, past 180-day use, age of first use, and lifetime CUD symptoms).

RESULTS

Significant genetic correlation between lifetime cannabis use and an eveningness chronotype (rG = 0.24, p < 0.001), as well as between CUD and both short sleep duration (<7 h; rG = 0.23, p = 0.017) and insomnia (rG = 0.20, p = 0.020). Insomnia PRS predicted earlier age of first cannabis use (OR = 0.92, p = 0.036) and increased lifetime CUD symptom count (OR = 1.09, p = 0.012).

CONCLUSION

Cannabis use is genetically associated with both sleep deficits and an eveningness chronotype, suggesting that there are genes that predispose individuals to both cannabis use and sleep deficits.

Cannabis for Chronic Pain: A Rapid Systematic Review of Randomized Control Trials

BACKGROUND

The high prevalence of inadequately managed chronic pain indicates the need for alternative and multimodal treatment options. Use of cannabinoids in medicine is becoming a growing area of interest, specifically in the context of chronic pain. The efficacy of cannabinoids for the treatment of chronic pain is not well established.

AIMS

The objectives of this rapid systematic literature review are to summarize the efficacy and secondary effects of cannabinoids for chronic pain management.

DESIGN

Rapid systematic review of randomized control trials.

PARTICIPANTS

Individuals with chronic pain (n = 1352).

METHODS

Embase, Cochrane, PubMed, and CINAHL databases were searched. Inclusion criteria included cannabis of any formulation used to treat chronic pain of any origin.

RESULTS

Thirteen randomized controlled trials met the inclusion criteria. Five demonstrated moderate analgesic effects of cannabis for chronic pain, and eight concluded there were no significant impacts on pain in the cannabis-treated group versus the control group.

CONCLUSIONS

Evidence on the efficacy of cannabinoids for chronic pain shows patient-perceived benefit but inconsistent other treatment effects. These findings indicate cannabinoids may have a modest analgesic effect for chronic neuropathic pain conditions, and that the use of cannabinoids is relatively safe, with few severe adverse events. This review concludes that cannabinoids may have a potential role in chronic pain management. Inconsistent evidence on the efficacy of cannabis to treat chronic pain indicates the need for more studies on a larger scale. Clinicians should draw on available evidence and consider cannabinoids as a potential approach to chronic pain management.

Medical Cannabis in Oncology: a Valuable Unappreciated Remedy or an Undesirable Risk?

OPINION STATEMENT

The use of the cannabis plant by cancer patients has been rising significantly in the past few years worldwide, primarily driven by public demand. There is an obvious need for more reliable scientific data, pharmacology information, a better understanding of its mode of action, and available clinical evidence supporting its robust use. Physicians must complete a thorough medical assessment, screening for potential drugs, or treatment contraindications before allowing its consumption. In light of the growing popularity of cannabis usage, it is highly essential that, in the near future, the medical community will be able to provide practical recommendations and explicit guidelines, including doses, and that cannabinoid concentrations in the used products are defined regarding its prescription before any medical procedure involving its usage is authorized. Here, we review and describe the favorable outcomes demonstrating the benefits of cannabis as an adjunctive treatment to conventional medicines for chemotherapy-induced nausea, vomiting, and cancer-related pain (primarily refractory chronic or neuropathic pain). Although not yet substantial enough, the treatment of anorexia, insomnia, depression, and anxiety is also seemingly favorable. To date, reports regarding its anti-neoplastic effects or its potent immunosuppressive properties influencing response to immunotherapy are still very conflicting and controversial. Thus, with the current state of evidence, cannabis use is not advisable as initial treatment, as an adjunct or an advanced line of care. In the coming years, we expect that preclinical data and animal models will shift to the clinical arena, and more patients will be recruited for clinical trials, and their reports will advance the field. Thus, physicians should prescribe cannabis only if careful clarification and consideration is provided together with a follow-up response evaluation.

Cannabinoids in the Treatment of Back Pain

Marijuana is increasingly utilized for the treatment of multiple medical problems, including back pain, in the United States. Although there is strong preclinical evidence supporting the promise of cannabinoids in the treatment of back pain, there is a paucity of clinical data supporting their use in clinical practice. Opioids are an important medication for the treatment of acute and chronic back pain, but utilization of opioid-based regimens have likely contributed to the growing opioid epidemic. The significant risk of morbidity, mortality, and dependence secondary to opioid medications have increased the interest in nonopioid medications, including cannabinoid-based pain regimens, in treating back pain. This review will provide an overview on the pharmacology, drug delivery methods, clinical evidence, and safety considerations critical to understanding the potential role of cannabinoids in the treatment of back pain.

Pharmacist Views Regarding the Prescription Opioid Epidemic

Community pharmacists have significant opportunity to contribute to prevention and treatment of opioid use disorders, but barriers to implementation still exist. Understanding their viewpoints is critical to designing future interventions. To qualitatively explore experiences and beliefs of community pharmacists regarding the misuse of prescription opioids in the United States. The study was part of a larger project that utilized a survey questionnaire to evaluate the relationships between knowledge, attitudes, and practices of community pharmacists in substance use disorders. The survey included an open-ended item on pharmacist views regarding the prescription opioid epidemic. The responses were used for inductive content analysis. Axial coding of themes was conducted to analyze underlying relationships: associations, consequences, intervening relationships, and action strategies regarding a central phenomenon. A model describing pharmacist experiences in the opioid epidemic was conceptualized. The open-ended question resulted in 50 (37.3%) usable responses. Final abstraction resulted in six themes including (1) overprescribing opioids: inappropriate prescribing as a contributor to the epidemic, (2) policy and practice recommendations: potential action strategies against the epidemic, (3) poor prescriber-pharmacist relationship: barrier to addressing the epidemic, (4) negative attitudes: intervening condition affecting roles of the pharmacist, (5) personal experience: facilitator to improve pharmacist roles and (6) decreased access to opioids: consequence of strict prescribing laws. The study identified themes that described pharmacist views, attitudes, barriers, and experiences related to their perceived role in prevention and treatment of opioid use disorders. Future research should consider the implications of the barriers and facilitators identified.

Cannabis use and sleep: Expectations, outcomes, and the role of age

STUDY OBJECTIVES

Determine relationship between cannabis use with 1) expectations of cannabis being a sleep aid, 2) subjective sleep outcomes, and 3) the influence of age on these relationships.

METHODS

In 152 moderate cannabis users with a wide age range (67% female, mean age = 31.45, SD = 12.96, age range = 21-70; mean days of cannabis use in prior two weeks = 5.54, SD = 5.25) we examined the influence of cannabis use history and behaviors on expectations of cannabis being a sleep aid and sleep outcomes via the Pittsburgh Sleep Quality Index (PSQI). Moderation analysis examined the role of age in the relationship between cannabis use and sleep outcomes.

RESULTS

Endorsing current cannabis use and more days of cannabis use were associated with increased expectations that cannabis use improves sleep (all β > 0.03, p < 0.04). Frequency of recent use and reported average THC or CBD concentration were largely not associated with sleep outcomes. However, endorsing current cannabis use was associated with worse subjective sleep quality (β = 1.34, p = 0.02) and increased frequency of consuming edibles was associated with worse subjective sleep efficiency (β = 0.03, p = 0.04), lower sleep duration (β = 0.03, p = 0.01), and higher global PSQI scores (worse overall sleep) (β = 0.10, p = 0.01). Additionally, age had a moderating influence on the relationship between increased self-reported concentration of CBD and both better sleep duration and sleep quality (both p < 0.03). While the main effects of cannabis use on sleep outcomes did not survive multiple comparisons correction test (all p adj > 0.34), the adjusted p values for the main effects of cannabis behaviors/history on expectations of cannabis as a sleep aid (p adj = 0.07-0.09) and the main effects of CBD concentration on sleep duration (p adj = 0.08), as well as the interaction terms of CBD and age for that model (p adj = 0.07), were trending.

CONCLUSION

Cannabis users have increased expectations of cannabis being a sleep aid, but few associations existed between cannabis use and sleep outcomes. The two exceptions were endorsing any cannabis use and frequency of edible use. Additionally, age may be an important moderator of the potential positive influence CBD concentration can have on sleep.

Cannabinoid Receptors and Their Relationship With Chronic Pain: A Narrative Review

The burden of chronic pain has affected many individuals leading to distress and discomfort, alongside numerous side effects with conventional therapeutic approaches. Cannabinoid receptors are naturally found in the human body and have long been an interest in antinociception. These include CB1 and CB2 receptors, which are promising candidates for the treatment of chronic inflammatory pain. The mechanism of action of the receptors and how they approach pain control in inflammatory conditions show that it can be an adjunctive approach towards controlling these symptoms. Numerous studies have shown how the targeted approach towards these receptors has activated them promoting a release in cytokines, all leading to anti-inflammatory effects and immune system regulation. Cannabinoid activation of glycine and gamma-aminobutyric acid (GABA) models also showed efficacy in pain management. Chronic conditions such as osteoarthritis were shown to also benefit from this considerable treatment. However, it is unclear how the cannabinoid system works in relation with the pain pathway. Therefore, in this review we aim to analyse the role of the cannabinoid system in chronic inflammatory pain.

Cannabis and cannabidiol (CBD) for the treatment of fibromyalgia

Fibromyalgia is a complex disease process that is as prevalent as it is poorly understood. Research into the pathophysiology is ongoing, and findings will likely assist in identifying new therapeutic options to augment those in existence today that are still insufficient for the care of a large population of patients. Recent evidence describes the use of cannabinoids in the treatment of fibromyalgia. This study provides a systematic, thorough review of the evidence alongside a review of the seminal data regarding the pathophysiology, diagnosis, and current treatment options. Fibromyalgia is characterized by widespread chronic pain, fatigue, and depressive episodes without an organic diagnosis, which may be prevalent in up to 10% of the population and carries a significant cost in healthcare utilization, morbidity, a reduced quality of life, and productivity. It is frequently associated with psychiatric comorbidities. The diagnosis is clinical and usually prolonged, and diagnostic criteria continue to evolve. Some therapies have been previously described, including neuropathic medications, milnacipran, and antidepressants. Despite some level of efficacy, only physical exercise has strong evidence to support it. Cannabis has been used historically to treat different pain conditions since ancient times. Recent advances allowed for the isolation of the active substances in cannabis and the production of cannabinoid products that are nearly devoid of psychoactive influence and provide pain relief and alleviation of other symptoms. Many of these, as well as cannabis itself, are approved for use in chronic pain conditions. Evidence supporting cannabis in chronic pain conditions is plentiful; however, in fibromyalgia, they are mostly limited. Only a handful of randomized trials exists, and their objectivity has been questioned. However, many retrospective trials and patient surveys suggest the significant alleviation of pain, improvement in sleep, and abatement of associated symptoms. Evidence supporting the use of cannabis in chronic pain and specifically in fibromyalgia is being gathered as the use of cannabis increases with current global trends. While the current evidence is still limited, emerging data do suggest a positive effect of cannabis in fibromyalgia. Cannabis use is not without risks, including psychiatric, cognitive, and developmental as well as the risks of addiction. As such, clinical judgment is warranted to weigh these risks and prescribe to patients who are more likely to benefit from this treatment. Further research is required to define appropriate patient selection and treatment regimens.

Youth marijuana use: a review of causes and consequences

The legalization of medical and recreational marijuana has raised concerns about a potential increase in the availability and illegal use of marijuana by adolescent minors. To better understand the etiology, patterns, and consequences of adolescent marijuana use, this article reviews high quality, methodologically rigorous, longitudinal studies that focus on the role of personality factors such as sensation-seeking in the etiology of use, developmental trajectories of use and the effects of chronic use, potential gateway effects of marijuana on other illicit drugs, and its role in the onset of psychiatric disorders in adolescents and young adults. Implications are discussed in terms of mechanisms that account for initial and continued use of marijuana by adolescents, how use is associated with key developmental milestones and adult role socialization, and the potential of marijuana use during adolescence in furthering later drug involvement.

Synthetic bioactive olivetol-related amides: The influence of the phenolic group in cannabinoid receptor activity

Focusing on the importance of the free phenolic hydroxyl moiety, a family of 23 alkylresorcinol-based compounds were developed and evaluated for their cannabinoid receptor binding properties. The non-symmetrical hexylresorcinol derivative 29 turned out to be a CB2-selective competitive antagonist/inverse agonist endowed with good potency. Both the olivetol- and 5-(2-methyloctan-2-yl)resorcinol-based derivatives 23 and 24 exhibited a significant antinociceptive activity. Interestingly, compound 24 proved to be able to activate both cannabinoid and TRPV1 receptors. Even if cannabinoid receptor subtype selectivity remained a goal only partially achieved, results confirm the validity of the alkylresorcinol nucleus as skeleton for the identification of potent cannabinoid receptor modulators.

Cannabinoids in Pain Treatment: An Overview

The current landscape contains conflicting reports regarding the use of medical marijuana, creating fields of misinformation and lack of understanding by health care providers about cannabinoids. In this article we provide a dispassionate look at medical marijuana, while providing a clinical overview focusing on pain management. We examine the mechanisms of the endocannabinoid system, along with the pharmacology of cannabinoids. Current research on the use of marijuana for the treatment of pain is reviewed. Finally, recommendations for pain management nurses on integrating research, clinical practice, and U.S. drug policy are made.

Targeting Peripherally Restricted Cannabinoid Receptor 1, Cannabinoid Receptor 2, and Endocannabinoid-Degrading Enzymes for the Treatment of Neuropathic Pain Including Neuropathic Orofacial Pain

Neuropathic pain conditions including neuropathic orofacial pain (NOP) are difficult to treat. Contemporary therapeutic agents for neuropathic pain are often ineffective in relieving pain and are associated with various adverse effects. Finding new options for treating neuropathic pain is a major priority in pain-related research. Cannabinoid-based therapeutic strategies have emerged as promising new options. Cannabinoids mainly act on cannabinoid 1 (CB1) and 2 (CB2) receptors, and the former is widely distributed in the brain. The therapeutic significance of cannabinoids is masked by their adverse effects including sedation, motor impairment, addiction and cognitive impairment, which are thought to be mediated by CB1 receptors in the brain. Alternative approaches have been developed to overcome this problem by selectively targeting CB2 receptors, peripherally restricted CB1 receptors and endocannabinoids that may be locally synthesized on demand at sites where their actions are pertinent. Many preclinical studies have reported that these strategies are effective for treating neuropathic pain and produce no or minimal side effects. Recently, we observed that inhibition of degradation of a major endocannabinoid, 2-arachydonoylglycerol, can attenuate NOP following trigeminal nerve injury in mice. This review will discuss the above-mentioned alternative approaches that show potential for treating neuropathic pain including NOP.

Effect of cannabis on opioid use in patients with cancer receiving palliative care

OBJECTIVE

Opioids are the primary therapy for cancer-related pain in patients receiving palliative care. More states are legalizing medical cannabis, which may provide a pain management alternative for some of these patients. This study aimed to estimate the effect of cannabis on opioid use in patients with cancer receiving palliative care.

METHODS

This was a retrospective cohort study of patients with cancer at an academic medical center palliative care clinic. The primary outcome was change in morphine equivalent daily dose (MEDD) from baseline to 84-day follow-up in the cannabis plus opioid group compared to that in the opioid-only group.

RESULTS

A total of 83 patients were included: 61 in the opioid monotherapy group and 22 in the cannabis plus opioid group. An increase in MEDD from the baseline to 84 days was seen in both the opioid monotherapy and opioid plus cannabis group (28.8 vs. 10.8); however, the study lacked power to detect a statistical difference.

CONCLUSION

A possibly meaningful difference in MEDD increase was seen when comparing the opioid monotherapy group with the opioid plus cannabis group. However, the study was not powered to test this hypothesis; the findings suggest that further research is warranted to determine the impact of cannabis use on opioid dosing in patients receiving palliative care for cancer.

Cannabidiol increases the nociceptive threshold in a preclinical model of Parkinson's disease

Medications that improve pain threshold can be useful in the pharmacotherapy of Parkinson's disease (PD). Pain is a prevalent PD's non-motor symptom with a higher prevalence of analgesic drugs prescription for patients. However, specific therapy for PD-related pain are not available. Since the endocannabinoid system is expressed extensively in different levels of pain pathway, drugs designed to target this system have promising therapeutic potential in the modulation of pain. Thus, we examined the effects of the 6-hydroxydopamine- induced PD on nociceptive responses of mice and the influence of cannabidiol (CBD) on 6-hydroxydopamine-induced nociception. Further, we investigated the pathway involved in the analgesic effect of the CBD through the co-administration with a fatty acid amide hydrolase (FAAH) inhibitor, increasing the endogenous anandamide levels, and possible targets from anandamide, i.e., the cannabinoid receptors subtype 1 and 2 (CB1 and CB2) and the transient receptor potential vanilloid type 1 (TRPV1). We report that 6-hydroxydopamine- induced parkinsonism decreases the thermal and mechanical nociceptive threshold, whereas CBD (acute and chronic treatment) reduces this hyperalgesia and allodynia evoked by 6-hydroxydopamine. Moreover, ineffective doses of either FAAH inhibitor or TRPV1 receptor antagonist potentialized the CBD-evoked antinociception while an inverse agonist of the CB1 and CB2 receptor prevented the antinociceptive effect of the CBD. Altogether, these results indicate that CBD can be a useful drug to prevent the parkinsonism-induced nociceptive threshold reduction. They also suggest that CB1 and TRPV1 receptors are important for CBD-induced analgesia and that CBD could produce these analgesic effects increasing endogenous anandamide levels.

Combination of cannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), mitigates experimental autoimmune encephalomyelitis (EAE) by altering the gut microbiome

Currently, a combination of marijuana cannabinoids including delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) is used as a drug to treat muscle spasticity in patients with Multiple Sclerosis (MS). Because these cannabinoids can also suppress inflammation, it is unclear whether such patients benefit from suppression of neuroinflammation and if so, what is the mechanism through which cannabinoids act. In the currently study, we used a murine model of MS, experimental autoimmune encephalomyelitis (EAE), to study the role of gut microbiota in the attenuation of clinical signs of paralysis and inflammation caused by cannabinoids. THC + CBD treatment attenuated EAE and caused significant decrease in inflammatory cytokines such as IL-17 and IFN-γ while promoting the induction of anti-inflammatory cytokines such as IL-10 and TGF-β. Use of 16S rRNA sequencing on bacterial DNA extracted from the gut revealed that EAE mice showed high abundance of mucin degrading bacterial species, such as Akkermansia muciniphila (A. muc), which was significantly reduced after THC + CBD treatment. Fecal Material Transfer (FMT) experiments confirmed that THC + CBD-mediated changes in the microbiome play a critical role in attenuating EAE. In silico computational metabolomics revealed that LPS biosynthesis, a key component in gram-negative bacteria such as A. muc, was found to be elevated in EAE mice which was confirmed by demonstrating higher levels of LPS in the brain, while treatment with THC + CBD reversed this trend. EAE mice treated with THC + CBD also had significantly higher levels of short chain fatty acids such as butyric, isovaleric, and valeric acids compared to naïve or disease controls. Collectively, our data suggest that cannabinoids may attenuate EAE and suppress neuroinflammation by preventing microbial dysbiosis seen during EAE and promoting healthy gut microbiota.

Associations of PTSD, chronic pain, and their comorbidity on cannabis use disorder: Results from an American nationally representative study

BACKGROUND

Cannabis can be prescribed for posttraumatic stress disorder (PTSD) and chronic pain, and comorbid cannabis use disorder (CUD) can occur in both conditions. Research demonstrates that PTSD and chronic pain commonly co-occur.

METHODS

Data were acquired from the National Epidemiologic Survey on Alcohol and Related Conditions-III (N = 36,309). Past-year CUD and PTSD were assessed using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-5. Past-year physician-confirmed chronic pain was self-reported and classified as musculoskeletal (e.g., arthritis), digestive (e.g., pancreatitis), and nerve (e.g., reflex sympathetic dystrophy) pain. Weighted cross-tabulations assessed sociodemographic, psychiatric, and chronic pain condition variables among those with PTSD versus no PTSD, among the entire sample and among those with CUD and chronic pain. Multiple logistic regressions examined the relationship between PTSD and chronic pain with CUD. CUD characteristics were also evaluated across PTSD and chronic pain groups.

RESULTS

Rates of CUD were elevated in PTSD (9.4%) compared to those without (2.2%). The odds of CUD were greater for PTSD+digestive pain, PTSD+nerve pain, and PTSD+any chronic pain compared to having neither PTSD nor chronic pain (odds ratio range: 1.88-2.32). PTSD with and without comorbid chronic pain was associated with overall elevated rates of adverse CUD characteristics, including earlier age of onset, greater usage, and greater CUD severity.

CONCLUSIONS

PTSD with and without chronic pain is associated with elevated rates and severity of CUD. These results may have implications for prescribing practices and understanding individuals at risk for developing CUD.

The endocannabinoid system: Novel targets for treating cancer induced bone pain

Treating Cancer-induced bone pain (CIBP) continues to be a major clinical challenge and underlying mechanisms of CIBP remain unclear. Recently, emerging body of evidence suggested the endocannabinoid system (ECS) may play essential roles in CIBP. Here, we summarized the current understanding of the antinociceptive mechanisms of endocannabinoids in CIBP and discussed the beneficial effects of endocannabinoid for CIBP treatment. Targeting non-selective cannabinoid 1 receptors or selective cannabinoid 2 receptors, and modulation of peripheral AEA and 2-AG, as well as the inhibition the function of fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) have produced analgesic effects in animal models of CIBP. Management of ECS therefore appears to be a promising way for the treatment of CIBP in terms of efficacy and safety. Further clinical studies are encouraged to confirm the possible translation to humans of the very promising results already obtained in the preclinical studies.

Cannabis and Male Fertility: A Systematic Review

PURPOSE

With cannabis consumption on the rise and use prominent among males of reproductive age it is essential to understand the potential impact of cannabis on male fertility. We reviewed the literature regarding the effects of cannabis on male fertility.

MATERIALS AND METHODS

We performed a literature search using PubMed®/MEDLINE® to identify relevant studies of the effects of cannabis on male fertility. Relevant studies were identified and reviewed.

RESULTS

The strongest evidence of cannabis induced alterations in male fertility is in the category of semen parameters. Research supports a role for cannabis in reducing sperm count and concentration, inducing abnormalities in sperm morphology, reducing sperm motility and viability, and inhibiting capacitation and fertilizing capacity. Animal models demonstrate a role for cannabis in testicular atrophy, and reduced libido and sexual function but to our knowledge these results have not yet been replicated in human studies. Studies of hormonal changes suggest inconclusive effects on testosterone levels, lowered luteinizing hormone levels and unchanged follicle-stimulating hormone levels.

CONCLUSIONS

Current research suggests that cannabis may negatively impact male fertility. Further studies are needed to validate that robust findings in animal models will carry over into human experience. Clinicians should be aware of these potential effects when prescribing medical marijuana therapies to men of reproductive age, and they should consider the degree of cannabis use as a possible component of a complete male infertility workup.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

Evaluating the efficacy of cannabidiol to manage surgically induced neuropathic pain in a preclinical rat model: Are T cells a sexually dimorphic target?

Background: Considering the poorly understood etiology and complex symptoms of chronic neuropathic pain (NP), the lack of effective treatments, and sex-dependent differences in the neuroimmune system as well as in antinociceptive responses to existing pharmacological agents, the potential to therapeutically target the endocannabinoid system as a means of treating this type of intractable pain is clinically relevant and timely. Chronic NP may involve the utilization of distinct immune cell populations in males and females that differentially affect supraspinal and spinal neuromodulation. It is therefore important to investigate the effects of cannabidiol (CBD) on chronic NP-induced nociceptive responses in both sexes.

Aims: Evaluating whether the expression of markers associated with CD4⁺ T cells are affected by CBD in a sexually dimorphic manner will provide key insights into the contribution of these adaptive immune cells to the onset and progression of NP.

Methods: Future research will be directed toward examining the potential sex-dependent effects of this nonpsychotropic cannabinoid relative to vehicle in a preclinical model of chronic postsurgical NP. Specifically, (1) differences in nociceptive behavior, (2) chronic changes in neural firing patterns, and (3) up- or downregulation of markers associated with CD4⁺ T cells in relevant tissues will be evaluated to better understand CBD-mediated neuroimmune modulatory effects in males and females.

Conclusions: Chronic postsurgical pain is a growing clinical problem. Current treatment strategies rely on opioid-based therapeutics, which affect patient quality of life and are associated with addiction and withdrawal. Treatment of nerve injuries with CBD could provide an effective alternative to manage NP. Understanding its mechanisms of action will provide important insights into the sex-dependent application of this nonpsychoactive cannabinoid, setting the groundwork for large-scale Canadian clinical trials in women and men presenting with chronic pain.

Screening for neuropathic pain in patients with sickle cell disease: is a single assessment scale sufficient?

Background

The objectives of this study were to delineate the clinical-epidemiological profile of patients with neuropathic pain (NP) in the groups of SCD patients, from each of the three questionnaires used DN-4, painDETECT - PDQ, LANSS and to compare these three questionnaires in NP evaluation in SCD carriers. This cross-sectional study evaluated 83 patients with symptomatic SCD, aged 14 years or older. Clinical and laboratory data were extracted from the patients’ charts and from information obtained from the patients during the interview before the application of the questionnaire. The calculations were performed using the statistical software Epi InfoTM 7. Pearson’s correlation coefficient was used to compare the neuropathic pain evaluation scales with the software BioEstat 5.3.

Results

The use of two or more questionnaires may increase the suspicion of NP in patients with SCD and, with a confirmed diagnosis, adequate treatments will benefit patients.

Aging circadian rhythms and cannabinoids

Numerous aspects of mammalian physiology exhibit cyclic daily patterns known as circadian rhythms. However, studies in aged humans and animals indicate that these physiological rhythms are not consistent throughout the life span. The simultaneous development of disrupted circadian rhythms and age-related impairments suggests a shared mechanism, which may be amenable to therapeutic intervention. Recently, the endocannabinoid system has emerged as a complex signaling network, which regulates numerous aspects of circadian physiology relevant to the neurobiology of aging. Agonists of cannabinoid receptor-1 (CB1) have consistently been shown to decrease neuronal activity, core body temperature, locomotion, and cognitive function. Paradoxically, several lines of evidence now suggest that very low doses of cannabinoids are beneficial in advanced age. One potential explanation for this phenomenon is that these drugs exhibit hormesis-a biphasic dose-response wherein low doses produce the opposite effects of higher doses. Therefore, it is important to determine the dose-, age-, and time-dependent effects of these substances on the regulation of circadian rhythms and other processes dysregulated in aging. This review highlights 3 fields-biological aging, circadian rhythms, and endocannabinoid signaling-to critically assess the therapeutic potential of endocannabinoid modulation in aged individuals. If the hormetic properties of exogenous cannabinoids are confirmed, we conclude that precise administration of these compounds may bidirectionally entrain central and peripheral circadian clocks and benefit multiple aspects of aging physiology.

Role of endocannabinoid system in dopamine signalling within the reward circuits affected by chronic pain

The association between chronic pain, depression and anxiety has gained particular attention due to high rates of comorbidity. Recent data demonstrated that the mesolimbic reward circuitry is involved in the pathology of chronic pain. Interestingly, the mesolimbic reward circuit participates both in pain perception and in pain relief. The endocannabinoid system (ECS) has emerged as a highly relevant player involved in both pain perception and reward processing. Targeting ECS could become a novel treatment strategy for chronic pain patients. However, little is known about the underlying mechanisms of action of cannabinoids at the intersection of neurochemical changes in reward circuits and chronic pain. Because understanding the benefits and risks of cannabinoids is paramount, the aim of this review is to evaluate the state-of-art knowledge about the involvement of the ECS in dopamine signalling within the reward circuits affected by chronic pain.

Cannabis Legalization Does Not Influence Patient Compliance with Opioid Therapy

BACKGROUND

Prescription opioid use and opioid related deaths continue to increase nationwide. Several states have adopted legislation allowing for recreational use of cannabis. Little is known about how recreational cannabis laws impact compliance in chronic pain patients who have been prescribed opioid therapy. The goals of this study were to (1) retrospectively assess the effect of cannabis use on compliance with opioid therapy in a high-risk patient population and (2) determine the impact of legalization of recreational cannabis on patients prescribed therapeutic opioids.

METHODS

We conducted a retrospective cohort study on results from a "high-risk" urine drug testing panel. Results from 1 year before and 1 year after initiation of recreational cannabis legislation were analyzed. This testing panel included qualitative assays for cannabinoids and 9 other common drugs of abuse in addition to a quantitative LC-MS/MS assay for 23 different opioids and metabolites. Opioid compliance was assigned by reviewing pathologists' interpretations.

RESULTS

In the pre-legalization period, 1776 panels were performed, and in the post-legalization, 1648 panels were performed. An increase (6%) in the rate of positive cannabinoids screening results was observed after legalization of recreational cannabis; however, the overall compliance rate was consistent.

CONCLUSIONS

The results of this study suggest that legalization of recreational cannabis does not affect compliance rate in patients treated with opioid therapy for chronic pain.

Multidisciplinary Pain Management for Pediatric Patients with Acute and Chronic Pain: A Foundational Treatment Approach When Prescribing Opioids

Opioid therapy is the cornerstone of treatment for acute procedural and postoperative pain and is regularly prescribed for severe and debilitating chronic pain conditions. Although beneficial for many patients, opioid therapy may have side effects, limited efficacy, and potential negative outcomes. Multidisciplinary pain management treatments incorporating pharmacological and integrative non-pharmacological therapies have been shown to be effective in acute and chronic pain management for pediatric populations. A multidisciplinary approach can also benefit psychological functioning and quality of life, and may have the potential to reduce reliance on opioids. The aims of this paper are to: (1) provide a brief overview of a multidisciplinary pain management approach for pediatric patients with acute and chronic pain, (2) highlight the mechanisms of action and evidence base of commonly utilized integrative non-pharmacological therapies in pediatric multidisciplinary pain management, and (3) explore the opioid sparing effects of multidisciplinary treatment for pediatric pain.

Some Prospective Alternatives for Treating Pain: The Endocannabinoid System and Its Putative Receptors GPR18 and GPR55

Background: Marijuana extracts (cannabinoids) have been used for several millennia for pain treatment. Regarding the site of action, cannabinoids are highly promiscuous molecules, but only two cannabinoid receptors (CB₁ and CB₂) have been deeply studied and classified. Thus, therapeutic actions, side effects and pharmacological targets for cannabinoids have been explained based on the pharmacology of cannabinoid CB₁/CB₂ receptors. However, the accumulation of confusing and sometimes contradictory results suggests the existence of other cannabinoid receptors. Different orphan proteins (e.g., GPR18, GPR55, GPR119, etc.) have been proposed as putative cannabinoid receptors. According to their expression, GPR18 and GPR55 could be involved in sensory transmission and pain integration.

Methods: This article reviews select relevant information about the potential role of GPR18 and GPR55 in the pathophysiology of pain.

Results: This work summarized novel data supporting that, besides cannabinoid CB₁ and CB₂ receptors, GPR18 and GPR55 may be useful for pain treatment.

Conclusion: There is evidence to support an antinociceptive role for GPR18 and GPR55.

Pharmacological Strategies for Decreasing Opioid Therapy and Management of Side Effects from Chronic Use

As awareness increases about the side effects of opioids and risks of misuse, opioid use and appropriate weaning of opioid therapies have become topics of significant clinical relevance among pediatric populations. Critically ill hospitalized neonates, children, and adolescents routinely receive opioids for analgesia and sedation as part of their hospitalization, for both acute and chronic illnesses. Opioids are frequently administered to manage pain symptoms, reduce anxiety and agitation, and diminish physiological stress responses. Opioids are also regularly prescribed to youth with chronic pain. These medications may be prescribed during the initial phase of a diagnostic workup, during an emergency room visit; as an inpatient, or on an outpatient basis. Following treatment for underlying pain conditions, it can be challenging to appropriately wean and discontinue opioid therapies. Weaning opioid therapy requires special expertise and care to avoid symptoms of increased pain, withdrawal, and agitation. To address this challenge, there have been enhanced efforts to implement opioid-reduction during pharmacological therapies for pediatric pain management. Effective pain management therapies and their outcomes in pediatrics are outside the scope of this paper. The aims of this paper were to: (1) Review the current practice of opioid-reduction during pharmacological therapies; and (2) highlight concrete opioid weaning strategies and management of opioid withdrawal.

Outcomes, Registries and Medical Marijuana: Towards Establishing Dispensary Monitoring and Reporting Standards

The acceptance by a large number of state governments of medical marijuana dispensaries and the regulatory framework to support their licensing has put to one side the issue of monitoring and reporting outcomes. This is a major oversight. It is an untenable situation given the limited evidence base for the clinical benefits and risks associated with dispensed botanical marijuana. The purpose of this commentary is to propose that, as a condition of licensing, marijuana dispensaries should be required to establish a registry to support ongoing monitoring of patient response associated with botanical cannabis formulations. Patients should be monitored over the course of their treatment to assess, in the case of severe non-cancer pain as an example, pain intensity and functional status by pain location. The dispensary, in meeting required audit standards, should be in a position to report on patient response over baseline to the provider who has recommended botanical cannabis. As well, registries should be in a position to report to state licensing agencies response to therapy by target patient groups. Establishing site-specific registries should go some way to meeting the present evidence deficit for botanical marijuana, reducing barriers to its acceptance by providers, patients and health agencies.