Cannabinergic pain medicine: a concise clinical primer and survey of randomized-controlled trial results

The influence of genetics on the endocannabinoid system gene expression and relevance for targeting reproductive conditions

BACKGROUND

Endocannabinoids are small lipid molecules that have critical roles in cellular proliferation and function. They are produced locally with their concentrations controlled via the endocannabinoid system (ECS). The important cellular functions of endocannabinoids have made them and the proteins that modulate their expression targets of potential interest for treatment in many different diseases including gynaecological conditions. There is significant evidence of heredity differences in the response to both exogenous and endogenous cannabinoids that hampers the identification of effective targets. Whether compounds targeting endocannabinoids will be effective therefore may rely on personal differences mediated through genetic architecture. To investigate the source of individual differences, we investigated the effects of genetic variants on the expression of the endocannabinoid system genes at both a systemic and individual tissue level with a particular focus on the female reproductive system and the endometrium.

METHODS

We performed this analysis using publicly available datasets, including the 31,684 participants from the eQTLGen database and 838 donors to the GTEx database which includes 49 different sources of tissue, as well as an in-house database of 206 endometrial samples. Analysis of the eQTLGen data identified 22,020 eQTLs that influenced 43 of the selected 70 ECS genes.

RESULTS

A comparison across 49 different tissues that included at least 70 different individuals in the GTEx dataset identified eQTL for 69 of the 70 different genes, confirming a tissue-specific influence. Comparisons among 11 different physiological system indicated that the female reproductive system was associated with a fewer number of eQTLs. Finally, in the endometrium, we detected Bonferroni significant genetic effects on one individual gene fatty acid binding protein 3 (FABP3), an intracellular transporter that delivers endocannabinoids to the enzyme responsible for its inactivation, with a further 14 independent FDR significant eQTL for 13 ECS genes.

CONCLUSIONS

This is the first study to investigate the effects of genetic variants on the ECS gene transcription and indicates genetic variants have significant influence that are unique to each tissue. Our results highlight the effect of individual variation and the impact endocannabinoid based therapies may have on different tissue and physiological systems.

Prevalence, perceptions, and patterns of cannabis use among cardiac inpatients at a tertiary care hospital: A cross-sectional survey

Background

Cannabis use may adversely affect cardiovascular health. Patterns of use by cardiac patients are unknown. We evaluated the prevalence, perceptions, and patterns of cannabis use among cardiac inpatients.

Methods

A consecutive cross-section of cardiac inpatients, hospitalized between November 2019 and May 2020, were surveyed in-person or via telephone. Descriptive statistics and logistic regression were used to examine the characteristics of cannabis use.

Results

The prevalence of past-12-month cannabis use was 13.8% (95% confidence interval [CI]: 11.8%-16.0%). Characteristics independently associated with cannabis use were as follows: age < 64 years (< 44 years, odds ratio [OR] = 3.96 [95% CI: 1.65-9.53]; age 45-64 years, OR = 2.72 [95% CI: 1.65-4.47]); tobacco use in the previous 6 months (OR = 1.91 [95% CI: 1.18-3.07]); having a cannabis smoker in one's primary social group (OR = 4.17 [95% CI: 2.73-6.38]); and a history of a mental health diagnosis (OR = 1.82 [95% CI: 1.19-2.79]). Among those using cannabis, 70.5% reported smoking or vaping it; 47.2% reported daily use. Most did not know the tetrahydrocannabinol (THC; 71.6%) or cannabidiol (CBD; 83.3%) content of their cannabis, or the dose of cannabis in their edibles (66.7%). As defined by Canada's Lower Risk Cannabis Use Guidelines, 96.7% of cannabis users reported ≥ 1 higher-risk use behaviour (mean = 2.3, standard deviation = 1.2). Over 60% of patients expressed no intention to quit or reduce cannabis use in the next 6 months.

Conclusions

Cannabis use appears prevalent among cardiac patients. Most users demonstrated higher-risk use behaviours and low intentions to quit. Further work is needed to understand the impacts of cannabis use on the cardiovascular system and to develop guidelines and educational tools relating to lower-risk use, for cardiac patients and providers.

The Role of Cannabis, Cannabidiol and Other Cannabinoids in Chronic Pain. The Perspective of Physicians

Currently, there is a renewed interest in treatments with medical cannabis and cannabinoids. Based on an increasing number of publications over the last decades that permitted new insights into mechanisms, efficacy and safety of cannabinoids, the use of cannabinergic medications is authorised in an increasing number of European and non-European countries. The alleviation of chronic, painful conditions is, since thousands of years, one of the primary reasons for the use of cannabis. Depending on the country, a wide range of medicinal cannabis preparations are available:ranging from defined cultivars of medical cannabis, mainly varying in their THC:CBD ratio, that are inhaled or taken as whole plant extracts,to highly purified single cannabinoids, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD),or mixtures of two enriched extracts, standardised to a 1:1 ratio of THC:CBD (nabiximols). Although conflicting opinions continue to exist, the majority of reviews in the past concluded that medical cannabis and cannabinoids play a significant role in the management of pain. Surprisingly, systematic studies to date do not support an "entourage effect" of the other plant constituents of cannabis (mainly terpenoids) in treatment of chronic pain. An emerging cannabinoid is CBD which is the only cannabinergic medication available at present that does not cause the typical "cannabis high"; it is not a "controlled substance". However, despite years of research, there is either no study or no well-conducted, head-to-head, comparison available between different cannabis cultivars, between pure cannabinoids, and between pure cannabinoids and extracts. It remains unanswered which is the optimal treatment approach.

Clinical Relevance of Drug Interactions with Cannabis: A Systematic Review

Concomitant use of cannabis with other drugs may lead to cannabis–drug interactions, mainly due to the pharmacokinetic mechanism involving the family of CYP450 isoenzymes. This narrative systematic review aimed to systematize the available information regarding clinical relevance of cannabis–drug interactions. We utilized the PubMed/Medline database for this systematic review, using the terms drug interactions and cannabis, between June 2011 and June 2021. Articles with cannabis–drug interactions in humans, in English or Spanish, with full-text access were selected. Two researchers evaluated the article’s inclusion. The level of clinical relevance was determined according to the severity and probability of the interaction. Ninety-five articles were identified and twenty-six were included. Overall, 19 pairs of drug interactions with medicinal or recreational cannabis were identified in humans. According to severity and probability, 1, 2, 12, and 4 pairs of cannabis–drug interactions were classified at levels 1 (very high risk), 2 (high risk), 3 (medium risk), and 5 (without risk), respectively. Cannabis–warfarin was classified at level 1, and cannabis–buprenorphine and tacrolimus at level 2. This review provides evidence for both the low probability of the occurrence of clinically relevant drug interactions and the lack of evidence regarding cannabis–drug interactions.

Emergency Medicine Physicians Would Prefer Using Cannabis Over Opioids for First-Line Treatment of a Medical Condition if Provided With Medical Evidence: A National Survey

Objective: To determine emergency medicine (EM) physicians’ preferences for using medical cannabis versus opioids if medical cannabis was legalized.

Methods: We surveyed US physicians at the largest national EM conference (American College of Emergency Physicians’ Annual Conference) held in San Diego, CA from October 1 to 4, 2018. Of the thousands of conference participants approached, 539 US physicians completed the anonymous written survey, which represented 15.2% of the US physicians attending the conference.

Results: The mean age of the participants was 39.6 ± 10.9 years, men composed 57.5% of the participants, and whites made up 72.8% of the respondents. Participants practicing in medically legal (54.8%) and medically plus adult-use legal cannabis states (23.1%) totaled 77.9%. A majority (70.7%) of the participants believed that cannabis has medical value. EM physicians preferred cannabis over opioids as a first-line treatment addressing a medical condition provided that medical studies found that cannabis was equally effective (p < 0.001, X² = 36.8 [95% CI 2, 415]), and overwhelmingly preferred cannabis over opioids if it were more effective (p < 0.001, X² = 90.8 [95% CI 2, 415]). Physicians appeared to prefer opioids over cannabis if medical studies found that cannabis was less effective though it was not significant (p > 0.05). Subgroup analyses showed that belief in the medical value of cannabis significantly increased the odds ratio of choosing cannabis over opioids if cannabis was equally or more effective than opioids.

Conclusion: Our study shows that EM physicians believe cannabis has medical value and would prefer using cannabis over opioids if provided with equivalent findings. We believe our findings reflect EM physicians’ experience of the opioid epidemic and suggest the need for further study of this potential therapeutic.

A Phase 2 Randomised Clinical Trial Assessing the Tolerability of Two Different Ratios of Medicinal Cannabis in Patients With High Grade Gliomas

Background

Cannabis for cancer is very topical and, given the use of illicit cannabis preparations used in this vulnerable population, research investigating standardised, quality-assured medicinal cannabis is critical to inform clinicians and assist patient safety.

Methods

A randomized trial involving adult patients diagnosed with a high-grade glioma, no history of substance abuse, liver or kidney damage or myocardial infarction were eligible for inclusion in a tolerability study on two different ratios of medicinal cannabis. Baseline screening of brain morphology, blood pathology, functional status, and cognition was conducted. A retrospective control group was used for comparison for secondary outcomes.

Results

Participants (n=88) were on average 53.3 years old. A paired t-test assessed the Functional Assessment of Cancer Therapy for Brain Cancer (FACT-Br) between groups from baseline to week 12 found that the 1:1 ratio favoured both physical (p=0.025) and functional (p=0.014) capacity and improved sleep (p=0.009). Analysis of changes from baseline to week 12 also found 11% of 61 participants had a reduction in disease, 34% were stable, 16% had slight enhancement, and 10% had progressive disease. No serious adverse events occurred. Side effects included dry mouth, tiredness at night, dizziness, drowsiness.

Conclusion

This study demonstrated that a single nightly dose of THC-containing medicinal cannabis was safe, had no serious adverse effects and was well tolerated in patients. Medicinal cannabis significantly improved sleep, functional wellbeing, and quality of life.

Clinical Trial Registration

Australian New Zealand Clinical Trials Registry (ANZCTR) http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373556&isReview=true, identifier ACTRN12617001287325.

Cannabinoid receptor agonists from Conus venoms alleviate pain-related behavior in rats

Cannabinoid (CB) receptor agonists show robust antinociceptive effects in various pain models. However, most of the clinically potent CB1 receptor-active drugs derived from cannabis are considered concerning due to psychotomimetic side effects. Selective CB receptor ligands that do not induce CNS side effects are of clinical interest. The venoms of marine snail Conus are a natural source of various potent analgesic peptides, some of which are already FDA approved. In this study we evaluated the ability of several Conus venom extracts to interact with CB1 receptor. HEK293 cells expressing CB1 receptors were treated with venom extracts and CB1 receptor internalization was analyzed by immunofluorescence. Results showed C. textile (C. Tex) and C. miles (C. Mil) samples as the most potent. These were serially subfractionated by HPLC for subsequent analysis by internalization assays and for analgesic potency evaluated in the formalin test and after peripheral nerve injury. Intrathecal injection of C. Tex and C. Mil subfractions reduced flinching/licking behavior during the second phase of formalin test and attenuated thermal and mechanical allodynia in nerve injury model. Treatment with proteolytic enzymes reduced CB1 internalization of subfractions, indicating the peptidergic nature of CB1 active component. Further HPLC purification revealed two potent antinociceptive subfractions within C. Tex with CB1 and possible CB2 activity, with mild to no side effects in the CB tetrad assessment. CB conopeptides can be isolated from these active Conus venom-derived samples and further developed as novel analgesic agents for the treatment of chronic pain using cell based or gene therapy approaches.

Cannabinoids in the Management of Acute Pain: A Systematic Review and Meta-analysis

Objective: To synthesize the best evidence surrounding the efficacy of cannabinoids for acute pain in the clinical setting based on subjective pain scores and observed adverse effects. Design: Systematic review with meta-analysis. Data Sources: PubMed, Embase, Cochrane Databases, and Google Scholar. Eligibility Criteria: English-language randomized-controlled clinical trials comparing cannabinoids with placebo in patients with acute pain. Data Extraction and Synthesis: Study quality was assessed using the Cochrane risk of bias tool. All stages were conducted independently by a team of three reviewers. Data were pooled through meta-analysis and stratified by route of administration. Primary Outcomes and Measures: Patient-reported pain and adverse events (AEs). Results: Six trials (678 participants) were included examining oral (5 trials) and intramuscular (1 trial) cannabinoids. Overall, there was a small but statistically significant treatment effect favoring the use of cannabinoids over placebo (-0.90, 95% confidence interval [CI] -1.69 to -0.1, i 2=65%, p=0.03). When stratified by route of administration, intramuscular cannabinoids were found to have a significant reduction in pain relative to placebo (-2.98, 95% CI -4.09 to -1.87, i 2=0%, p<0.0001). No difference in effect was observed between oral cannabinoids and placebo (-0.21, 95% CI -0.64 to 0.22, i 2=3%, p=0.34). Serious AEs were rare, and similar across the cannabinoid (14/374, 3.7%) and placebo groups (8/304, 2.6%). Conclusions: There is low-quality evidence indicating that cannabinoids may be a safe alternative for a small but significant reduction in subjective pain score when treating acute pain, with intramuscular administration resulting in a greater reduction relative to oral. Higher quality, long-term randomized-controlled trials examining whether there may be a role for cannabinoids in treating acute pain are required.

Illicit Cannabis Usage as a Management Strategy in New Zealand Women with Endometriosis: An Online Survey

Background: Endometriosis affects around 10% of women worldwide. Many women with endometriosis struggle with finding adequate pain management, and data from other countries suggest that women use cannabis, either legal or illicit, to help manage their endometriosis symptoms. The aim of this study was to determine use of cannabis where endometriosis was self-identified as a condition that was being treated with cannabis, as well as the impact of cannabis use on the usage on other pharmaceuticals. Materials and Methods: A cross-sectional online survey of those using cannabis for health-related conditions run between May and July 2019. This article reports on the subset of this larger data set for those reporting they had a diagnosis of endometriosis and/or polycystic ovary syndrome. Data were collected on demographics, modes of cannabis administration, symptoms treated, changes in pharmaceutical usage, and adverse events. Results: Two hundred thirteen valid responses were analyzed. Mean age of respondents was 32 years and 79.8% were current cannabis users. The most common outcomes that cannabis was used for were to improve pain relief (95.5%) and to improve sleep (95.5%). Respondents reported that their symptom was "much better" for pain (81%), sleep (79%), and nausea or vomiting (61%). Over three-quarters (81.4%) indicated cannabis had reduced their normal medication usage. Over half (59%) were able to completely stop a medication, most commonly (66%) analgesics. Opioids (40%) were the most common class of analgesic stopped. Conclusions: Cannabis is reported as an effective intervention for pain and other endometriosis symptoms with potential substitution effects on opioid usage.

Chronological Review and Rational and Future Prospects of Cannabis-Based Drug Development

Despite the surge in cannabis chemistry research and its biological and medical activity, only a few cannabis-based pharmaceutical-grade drugs have been developed and marketed to date. Not many of these drugs are Food and Drug Administration (FDA)-approved, and some are still going through regulation processes. Active compounds including cannabinergic compounds (i.e., molecules targeted to modulate the endocannabinoid system) or phytocannabinoid analogues (cannabinoids produced by the plant) may be developed into single-molecule drugs. However, since in many cases treatment with whole-plant extract (whether as a solvent extraction, galenic preparation, or crude oil) is preferred over treatment with a single purified molecule, some more recently developed cannabis-derived drugs contain several molecules. Different combinations of active plant ingredients (API) from cannabis with proven synergies may be identified and developed as drugs to treat different medical conditions. However, possible negative effects between cannabis compounds should also be considered, as well as the effect of the cannabis treatment on the endocannabinoid system. FDA registration of single, few, or multiple molecules as drugs is a challenging process, and certain considerations that should be reviewed in this process, including issues of drug–drug interactions, are also discussed here.

The Impact of Medical Cannabis on Intermittent and Chronic Opioid Users with Back Pain: How Cannabis Diminished Prescription Opioid Usage

Objective: To determine if cannabis may be used as an alternative or adjunct treatment for intermittent and chronic prescription opioid users. Design: Retrospective cohort study. Setting: A single-center cannabis medical practice site in California. Patients: A total of 180 patients who had a chief complaint of low back pain were identified (International Classification of Diseases, 10th Revision, code M54.5). Sixty-one patients who used prescription opioids were analyzed. Interventions: Cannabis recommendations were provided to patients as a way to mitigate their low back pain. Outcome Measures: Number of patients who stopped opioids and change in morphine equivalents. Results: There were no between-group differences based on demographic, experiential, or attitudinal variables. We found that 50.8% were able to stop all opioid usage, which took a median of 6.4 years (IQR=1.75-11 years) after excluding two patients who transitioned off opioids by utilizing opioid agonists. For those 29 patients (47.5%) who did not stop opioids, 9 (31%) were able to reduce opioid use, 3 (10%) held the same baseline, and 17 (59%) increased their usage. Forty-eight percent of patients subjectively felt like cannabis helped them mitigate their opioid intake but this sentiment did not predict who actually stopped opioid usage. There were no variables that predicted who stopped opioids, except that those who used higher doses of cannabis were more likely to stop, which suggests that some patients might be able to stop opioids by using cannabis, particularly those who are dosed at higher levels. Conclusions: In this long-term observational study, cannabis use worked as an alternative to prescription opioids in just over half of patients with low back pain and as an adjunct to diminish use in some chronic opioid users.

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.

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.

Phytomedicines in the Treatment of Migraine

Migraine is a disabling neurovascular disorder with few targeted, tolerable and effective treatments. Phytomedicines, or plant-based medicinal formulations, hold great promise in the identification of novel therapeutic targets in migraine. Many patients also turn toward herbal and plant-based therapies for the treatment of their migraines as clinical and preclinical evidence of efficacy increases. Patients seek effective and tolerable treatments instead of or in addition to current conventional pharmacologic therapies. We review some phytomedicines potentially useful for migraine treatment-feverfew (Tanacetum parthenium), butterbur (Petasites hybridus), marijuana (Cannabis spp.), Saint John's Wort (Hypericum perforatum) and the Damask rose (Rosa × damascena)-with respect to their mechanisms of action and evidence for treatment of migraine. The evidence for feverfew is mixed; butterbur is effective with potential risks of hepatotoxicity related to preparation; marijuana has not been shown to be effective in migraine treatment, and data are scant; Saint John's Wort shows relevant physiological activity but is a hepatic enzyme inducer and lacks clinical studies for this purpose; the Damask rose when used in topical preparations did not show efficacy in one clinical trial. Other plant preparations have been considered for migraine treatment but most without blinded randomized, placebo-controlled trial evidence.

Self-management strategies amongst Australian women with endometriosis: a national online survey

Background

Endometriosis has a significant negative impact on the lives of women, and current medical treatments often do not give sufficient pain relief or have intolerable side effects for many women. The majority of women with primary dysmenorrhea use self-management strategies (including self-care techniques or lifestyle choices) to help manage period related symptoms, but little is known about self-management in women with endometriosis. The aim of this survey was to determine the prevalence of use, safety, and self-rated effectiveness of common forms of self-management.

Methods

A cross-sectional online survey was distributed via social media using endometriosis support and advocacy groups in Australia between October and December 2017. Women were eligible to answer the survey if they were 18–45, lived in Australia, and had a confirmed diagnosis of endometriosis. Survey questions covered the types of self-management used, improvements in symptoms or reduction in medication, and safety.

Results

Four hundred and eighty-four valid responses were received. Self-management strategies, consisting of self-care or lifestyle choices, were very common (76%) amongst women with endometriosis. The most common forms used were heat (70%), rest (68%), and meditation or breathing exercises (47%). Cannabis, heat, hemp/CBD oil, and dietary changes were the most highly rated in terms of self-reported effectiveness in pain reduction (with mean effectiveness of 7.6, 6.52, 6.33, and 6.39, respectively, on a 10-point scale). Physical interventions such as yoga/Pilates, stretching, and exercise were rated as being less effective. Adverse events were common, especially with using alcohol (53.8%) and exercise (34.2%).

Conclusions

Self-management was very commonly used by women with endometriosis and form an important part of self-management. Women using cannabis reported the highest self-rated effectiveness. Women with endometriosis have unique needs compared to women with primary dysmenorrhea, and therefore any self-management strategies, especially those that are physical in nature, need to be considered in light of the potential for ‘flare ups’.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2431-x) contains supplementary material, which is available to authorized users.

Patterns of medicinal cannabis use, strain analysis, and substitution effect among patients with migraine, headache, arthritis, and chronic pain in a medicinal cannabis cohort

BACKGROUND

Medicinal cannabis registries typically report pain as the most common reason for use. It would be clinically useful to identify patterns of cannabis treatment in migraine and headache, as compared to arthritis and chronic pain, and to analyze preferred cannabis strains, biochemical profiles, and prescription medication substitutions with cannabis.

METHODS

Via electronic survey in medicinal cannabis patients with headache, arthritis, and chronic pain, demographics and patterns of cannabis use including methods, frequency, quantity, preferred strains, cannabinoid and terpene profiles, and prescription substitutions were recorded. Cannabis use for migraine among headache patients was assessed via the ID Migraine™ questionnaire, a validated screen used to predict the probability of migraine.

RESULTS

Of 2032 patients, 21 illnesses were treated with cannabis. Pain syndromes accounted for 42.4% (n = 861) overall; chronic pain 29.4% (n = 598;), arthritis 9.3% (n = 188), and headache 3.7% (n = 75;). Across all 21 illnesses, headache was a symptom treated with cannabis in 24.9% (n = 505). These patients were given the ID Migraine™ questionnaire, with 68% (n = 343) giving 3 "Yes" responses, 20% (n = 102) giving 2 "Yes" responses (97% and 93% probability of migraine, respectively). Therefore, 88% (n = 445) of headache patients were treating probable migraine with cannabis. Hybrid strains were most preferred across all pain subtypes, with "OG Shark" the most preferred strain in the ID Migraine™ and headache groups. Many pain patients substituted prescription medications with cannabis (41.2-59.5%), most commonly opiates/opioids (40.5-72.8%). Prescription substitution in headache patients included opiates/opioids (43.4%), anti-depressant/anti-anxiety (39%), NSAIDs (21%), triptans (8.1%), anti-convulsants (7.7%), muscle relaxers (7%), ergots (0.4%).

CONCLUSIONS

Chronic pain was the most common reason for cannabis use, consistent with most registries. The majority of headache patients treating with cannabis were positive for migraine. Hybrid strains were preferred in ID Migraine™, headache, and most pain groups, with "OG Shark", a high THC (Δ9-tetrahydrocannabinol)/THCA (tetrahydrocannabinolic acid), low CBD (cannabidiol)/CBDA (cannabidiolic acid), strain with predominant terpenes β-caryophyllene and β-myrcene, most preferred in the headache and ID Migraine™ groups. This could reflect the potent analgesic, anti-inflammatory, and anti-emetic properties of THC, with anti-inflammatory and analgesic properties of β-caryophyllene and β-myrcene. Opiates/opioids were most commonly substituted with cannabis. Prospective studies are needed, but results may provide early insight into optimizing crossbred cannabis strains, synergistic biochemical profiles, dosing, and patterns of use in the treatment of headache, migraine, and chronic pain syndromes.

A prospective observational study of problematic oral cannabinoid use

BACKGROUND

Despite evidence supporting the benefits of cannabinoids for symptom control across a wide range of medical conditions, concerns have been raised regarding the potential misuse and/or problematic use of cannabinoids (CBs).

OBJECTIVE

The first objective of this study was to examine the incidence of problematic prescription cannabinoid use (PPCBU) over a 12-month period among patients initiating cannabinoid therapy. The second objective was to examine the factors associated with PPCBU. A total of 265 patients who were prescribed oral cannabinoid therapy as part of usual medical practice were enrolled into this prospective observational study. Patients first completed a series of baseline questionnaires assessing demographic, clinical, and substance use variables. Three measures designed to assess PPCBU were then administered at 3, 6, and 12 months after initiation of cannabinoid therapy.

RESULTS

At each of the follow-up assessment time points, a significantly greater number of patients scored below (vs above) cutoff scores on the three main PPCBU outcomes (all p's < .001). At any follow-up time point, a maximum of roughly 25% of patients demonstrated PPCBU. Heightened odds of PPCBU were observed among patients with a history of psychiatric problems, tobacco smokers, and recreational cannabis users (all p's < .05). Results indicated that past-year substance abuse, assessed using the DAST-20, was the strongest predictor of PPCBU (p < .005).

CONCLUSION

Findings from the present study could have implications for clinicians considering the use of cannabinoids for the management of patients with medical conditions. Although results indicated that the majority of patients included in this study did not reach cutoff scores on the three main PPCBU outcomes, our findings suggest that PPCBU should be routinely assessed and monitored over the course of cannabinoid therapy, particularly among patients with a history of psychiatric or substance use problems.

The Times They Are A-Changin': Knowledge and Perceptions Regarding Medical Cannabis in an Academic Family Medicine Department

Background and Objectives

The United States has seen an evolving perspective on the medical use of cannabis in recent years. Although a majority of states have enacted medical cannabis programs, physicians practicing in these states report a lack of knowledge, lingering concerns, and a need for more training regarding medical cannabis. This study provides a current snapshot of medical cannabis education in an academic family medicine department in a state with a medical cannabis program.

Methods

An electronic survey was sent to all 134 faculty physicians and residents within a family medicine department to assess current knowledge and attitudes regarding medical cannabis. Study authors performed descriptive statistical analysis of the survey data.

Results

Of the 61 individuals to complete the survey, 34 were residents and 27 were faculty. Overall, respondents displayed poor understanding of the state's medical cannabis program as well as cannabis regulations. A majority of both faculty and residents reported low self-rated competency levels for medical cannabis efficacy, adverse effects, and safety using Likert scales (1 to 5; 1=low competency, 5=high competency). A majority of faculty (56%) expressed that they did not intend to certify patients for medical cannabis compared to only 33% of residents. Residents were statistically more likely to think of a patient who might benefit from medical cannabis compared to faculty (39% vs 11%, P=.004, chi-square).

Conclusions

Increasingly, family physicians will be called on to provide informed patient counseling regarding medical cannabis. These results highlight a knowledge gap for family medicine learners in a changing practice landscape.

Cannabis and intractable chronic pain: an explorative retrospective analysis of Italian cohort of 614 patients

Background

Despite growing interest in the therapeutic use of cannabis to manage chronic pain, only limited data that address these issues are available. In recent years, a number of nations have introduced specific laws to allow patients to use cannabis preparations to treat a variety of medical conditions. In 2015, the Italian government authorized the use of cannabis to treat several diseases, including chronic pain generally, spasticity in multiple sclerosis, cachexia and anorexia among AIDS and cancer patients, glaucoma, Tourette syndrome, and certain types of epilepsy. We present the first snapshot of the Italian experience with cannabis use for chronic pain over the initial year of its use.

Methods

This is a retrospective case series analysis of all chronic pain patients treated with oral or vaporized cannabis in six hubs during the initial year following the approval of the new Italian law (December 2015 to November 2016). We evaluated routes of administration, types of cannabis products utilized, dosing, and effectiveness and safety of the treatment.

Results

As only one of the six centers has extensively used cannabinoids for intractable chronic pain (614 patients of 659), only the population from Azienda Ospedaliero Universitaria Pisana (Pisa) was considered. Cannabis tea was the primary mode of delivery, and in almost all cases, it was used in association with all the other pain treatments. Initial and follow-up cannabinoid concentrations were found to vary considerably. At initial follow-up, 76.2% of patients continued the treatment, and <15% stopped the treatment due to side effects (none of which were severe).

Conclusion

We present the first analysis of Italian clinical practice of the use of cannabinoids for a large variety of chronic pain syndromes. From this initial snapshot, we determined that the treatment seems to be effective and safe, although more data and subsequent trials are needed to better investigate its ideal clinical indication.

Substitution of medical cannabis for pharmaceutical agents for pain, anxiety, and sleep

A prior epidemiological study identified a reduction in opioid overdose deaths in US states that legalized medical cannabis (MC). One theory to explain this phenomenon is a potential substitution effect of MC for opioids. This study evaluated whether this substitution effect of MC for opioids also applies to other psychoactive medications. New England dispensary members ( n = 1,513) completed an online survey about their medical history and MC experiences. Among respondents that regularly used opioids, over three-quarters (76.7%) indicated that they reduced their use since they started MC. This was significantly ( p < 0.0001) greater than the patients that reduced their use of antidepressants (37.6%) or alcohol (42.0%). Approximately two-thirds of patients decreased their use of anti-anxiety (71.8%), migraine (66.7%), and sleep (65.2%) medications following MC which significantly ( p < 0.0001) exceeded the reduction in antidepressants or alcohol use. The patient's spouse, family, and other friends were more likely to know about their MC use than was their primary care provider. In conclusion, a majority of patients reported using less opioids as well as fewer medications to treat anxiety, migraines, and sleep after initiating MC. A smaller portion used less antidepressants or alcohol. Additional research is needed to corroborate these self-reported, retrospective, cross-sectional findings using other data sources.

A systematic review of the analgesic efficacy of cannabinoid medications in the management of acute pain

BACKGROUND

Cannabinergic medications have been postulated to demonstrate efficacy in the management of pain. The aim of this systematic review was to assess the analgesic efficacy and adverse effects of cannabinoids when used for the management of acute pain.

METHODS

A systematic review was performed by searching the MEDLINE, EMBASE and CENTRAL databases, and the World Health Organization International Clinical Trials Registry Platform for human randomized controlled trials that assessed the analgesic efficacy of cannabinoids compared to placebo or active comparators. The reported outcomes for analgesic efficacy and adverse effects in included studies were qualitatively analysed.

RESULTS

Seven studies, including 611 patients were included in the systematic review. In five studies, cannabinoids were found to provide equivalent analgesia to placebo, in one study the analgesia provided by cannabinoids was superior to placebo, and in one study cannabinoids provided analgesia that was inferior to that provided by placebo. No synergistic or additive analgesic effect was observed when cannabinoids were used in combination with opioids. In five of the seven studies, certain adverse effects were more frequent with cannabinoid treatment than with placebo or active comparator.

CONCLUSION

On the basis of the available randomized controlled trial evidence, cannabinoids have no role in the management of acute pain.

Targeting the Endocannabinoid System in Psychiatric Illness

Prevalence of psychiatric disorders continues to rise globally, yet remission rates and patient outcome remain less than ideal. As a result, novel treatment approaches for these disorders are necessary to decrease societal economic burden, as well as increase individual functioning. The recent discovery of the endocannabinoid system has provided an outlet for further research into its role in psychiatric disorders, because efficacy of targeted treatments have been demonstrated in medical illnesses, including cancers, neuropathic pain, and multiple sclerosis. The present review will investigate the role of the endocannabinoid system in psychiatric disorders, specifically schizophrenia, depressive, anxiety, and posttraumatic stress disorders, as well as attention-deficit hyperactivity disorder. Controversy remains in prescribing medicinal cannabinoid treatments due to the fear of adverse effects. However, one must consider all potential limitations when determining the safety and tolerability of cannabinoid products, specifically cannabinoid content (ie, Δ-tetrahydrocannabinol vs cannabidiol) as well as study design. The potential efficacy of cannabinoid treatments in the psychiatric population is an emerging topic of interest that provides potential value going forward in medicine.

Prevalence and correlates of "Vaping" as a route of cannabis administration in medical cannabis patients

PURPOSE

To examine the prevalence and correlates of vaporization (i.e., "vaping") as a route of cannabis administration in a sample of medical cannabis patients.

PROCEDURES

Adults ages 21 and older (N=1485M age=45.1) who were seeking medical cannabis certification (either for the first time or as a renewal) at medical cannabis clinics in southern Michigan completed a screening assessment. Participants completed measures of route of cannabis administration, cannabis use, alcohol and other substance use.

FINDINGS

An estimated 39% (n=511) of the sample reported past-month cannabis vaping, but vaping as the sole route of cannabis administration was rare. Specifically, only 30 participants (2.3% of the full sample and 5.9% of those who reported any vaping) indicated vaping as the sole route of cannabis administration. The majority (87.3%) of those who reported vaping also reported smoking (combustion) as a route of cannabis administration. Being younger than age 44, having more than a high school education, engaging in nonmedical stimulant use, being a returning medical cannabis patient, and greater frequency of cannabis use were associated with higher odds of vaping at the bivariate level and with all variables considered simultaneously.

CONCLUSIONS

Vaping appears to be relatively common among medical cannabis patients, but is seldom used as the sole route of cannabis administration.

RESULTS

highlight the importance of monitoring trends in vaping and other substance use behaviors in this population and underscore the need for longitudinal research into the motives, correlates, and consequences of cannabis vaping in medical cannabis patients.

Medicinal Cannabis: A Survey Among Health Care Providers in Washington State

INTRODUCTION

Washington State allows marijuana use for medical (since 1998) and recreational (since 2012) purposes. The benefits of medicinal cannabis (MC) can be maximized if clinicians educate patients about dosing, routes of administration, side effects, and plant composition. However, little is known about clinicians' knowledge and practices in Washington State.

METHODS

An anonymous online survey assessed providers' MC knowledge, beliefs, clinical practices, and training needs. The survey was disseminated through health care providers' professional organizations in Washington State. Descriptive analysis compared providers who had and had not authorized MC for patients. Survey results informed the approach and content of an online training on best clinical practices of MC.

RESULTS

Four hundred ninety-four health care providers responded to the survey. Approximately two-third were women, aged 30 to 60 years, and working in family or internal medicine. More than half of the respondents were legally allowed to write MC authorizations per Washington State law, and 27% of those had issued written MC authorizations. Overall, respondents reported low knowledge and comfort level related to recommending MC. Respondents rated MC knowledge as important and supported inclusion of MC training in medical/health provider curriculum. Most Washington State providers have not received education on scientific basis of MC or training on best clinical practices of MC. Clinicians who had issued MC authorizations were more likely to have received MC training than those who had not issued MC authorization.

DISCUSSION

The potential of MCs to benefit some patients is hindered by the lack of comfort of clinicians to recommend it. Training opportunities are badly needed to address these issues.

A Cross-Sectional Survey of Medical Cannabis Users: Patterns of Use and Perceived Efficacy

Background: The political climate around Cannabis as a medicine is rapidly changing. Legislators are adopting policies regarding appropriate medical applications, while the paucity of research may make policy decisions around conditions for which Cannabis is an effective medicine difficult. Methods: An anonymous online survey was developed to query medical Cannabis users about the conditions they use Cannabis to treat, their use patterns, perception of efficacy, and physical and mental health. Participants were recruited through social media and Cannabis dispensaries in Washington State. Results: A total of 1429 participants identified as medical Cannabis users. The most frequently reported conditions for which they used Cannabis were pain (61.2%), anxiety (58.1%), depression (50.3%), headache/migraine (35.5%), nausea (27.4%), and muscle spasticity (18.4%). On average, participants reported an 86% reduction in symptoms as a result of Cannabis use; 59.8% of medical users reported using Cannabis as an alternative to pharmaceutical prescriptions. Global health scores were on par with the general population for mental health and physical health. Conclusions: While patient-reported outcomes favor strong efficacy for a broad range of symptoms, many medical users are using Cannabis without physician supervision and for conditions for which there is no formal research to support the use of Cannabis (e.g., depression and anxiety). Future research and public policy should attempt to reduce the incongruence between approved and actual use.

Identification of Psychoactive Degradants of Cannabidiol in Simulated Gastric and Physiological Fluid

Introduction: In recent research, orally administered cannabidiol (CBD) showed a relatively high incidence of somnolence in a pediatric population. Previous work has suggested that when CBD is exposed to an acidic environment, it degrades to Δ⁹-tetrahydrocannabinol (THC) and other psychoactive cannabinoids. To gain a better understanding of quantitative exposure, we completed an in vitro study by evaluating the formation of psychoactive cannabinoids when CBD is exposed to simulated gastric fluid (SGF).

Methods: Materials included synthetic CBD, Δ⁸-THC, and Δ⁹-THC. Linearity was demonstrated for each component over the concentration range used in this study. CBD was spiked into media containing 1% sodium dodecyl sulfate (SDS). Samples were analyzed using chromatography with UV and mass spectrometry detection. An assessment time of 3 h was chosen as representative of the maximal duration of exposure to gastric fluid.

Results: CBD in SGF with 1% SDS was degraded about 85% after 60 min and more than 98% at 120 min. The degradation followed first-order kinetics at a rate constant of −0.031 min⁻¹ (R²=0.9933). The major products formed were Δ⁹-THC and Δ⁸-THC with less significant levels of other related cannabinoids. CBD in physiological buffer performed as a control did not convert to THC. Confirmation of THC formation was demonstrated by comparison of mass spectral analysis, mass identification, and retention time of Δ⁹-THC and Δ⁸-THC in the SGF samples against authentic reference standards.

Conclusions: SGF converts CBD into the psychoactive components Δ⁹-THC and Δ⁸-THC. The first-order kinetics observed in this study allowed estimated levels to be calculated and indicated that the acidic environment during normal gastrointestinal transit can expose orally CBD-treated patients to levels of THC and other psychoactive cannabinoids that may exceed the threshold for a physiological response. Delivery methods that decrease the potential for formation of psychoactive cannabinoids should be explored.

Medical marijuana for HIV-associated sensory neuropathy: legal and ethical issues

The number of states legalizing medical marijuana is increasing. Medical marijuana is possibly effective therapy for HIV-associated sensory neuropathy. Despite legalization at the state level, however, the current and contradictory federal drug enforcement policy creates the risk that physicians who recommend medical marijuana to their patients will lose their ability to prescribe medications. The federal-state tension has legal and ethical implications for neurologists who receive a request for medical marijuana from their patients since neurologists must strive to both relieve suffering and obey relevant laws. Recommendation of medical marijuana by neurologists to their patients is ethically permissible but is not ethically mandatory.

Comprehensive Review of Medicinal Marijuana, Cannabinoids, and Therapeutic Implications in Medicine and Headache: What a Long Strange Trip It's Been …

BACKGROUND

The use of cannabis, or marijuana, for medicinal purposes is deeply rooted though history, dating back to ancient times. It once held a prominent position in the history of medicine, recommended by many eminent physicians for numerous diseases, particularly headache and migraine. Through the decades, this plant has taken a fascinating journey from a legal and frequently prescribed status to illegal, driven by political and social factors rather than by science. However, with an abundance of growing support for its multitude of medicinal uses, the misguided stigma of cannabis is fading, and there has been a dramatic push for legalizing medicinal cannabis and research. Almost half of the United States has now legalized medicinal cannabis, several states have legalized recreational use, and others have legalized cannabidiol-only use, which is one of many therapeutic cannabinoids extracted from cannabis. Physicians need to be educated on the history, pharmacology, clinical indications, and proper clinical use of cannabis, as patients will inevitably inquire about it for many diseases, including chronic pain and headache disorders for which there is some intriguing supportive evidence.

OBJECTIVE

To review the history of medicinal cannabis use, discuss the pharmacology and physiology of the endocannabinoid system and cannabis-derived cannabinoids, perform a comprehensive literature review of the clinical uses of medicinal cannabis and cannabinoids with a focus on migraine and other headache disorders, and outline general clinical practice guidelines.

CONCLUSION

The literature suggests that the medicinal use of cannabis may have a therapeutic role for a multitude of diseases, particularly chronic pain disorders including headache. Supporting literature suggests a role for medicinal cannabis and cannabinoids in several types of headache disorders including migraine and cluster headache, although it is primarily limited to case based, anecdotal, or laboratory-based scientific research. Cannabis contains an extensive number of pharmacological and biochemical compounds, of which only a minority are understood, so many potential therapeutic uses likely remain undiscovered. Cannabinoids appear to modulate and interact at many pathways inherent to migraine, triptan mechanisms ofaction, and opiate pathways, suggesting potential synergistic or similar benefits. Modulation of the endocannabinoid system through agonism or antagonism of its receptors, targeting its metabolic pathways, or combining cannabinoids with other analgesics for synergistic effects, may provide the foundation for many new classes of medications. Despite the limited evidence and research suggesting a role for cannabis and cannabinoids in some headache disorders, randomized clinical trials are lacking and necessary for confirmation and further evaluation.

A survey of cannabis (marijuana) use and self-reported benefit in men with chronic prostatitis/chronic pelvic pain syndrome

INTRODUCTION

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a chronic pelvic pain condition largely refractory to treatment. Cannabis (marijuana) use has been reported for a wide variety of chronic pain conditions, but no study has examined prevalence of cannabis use, symptom benefit or side effects, or frequency in CP/CPPS.

METHODS

Participants were recruited from an outpatient CP/CPPS urology clinic (n = 98) and online through the Prostatitis Foundation website (n = 244). Participants completed questionnaires (demographics, CP/CPPS, depression, cannabis).

RESULTS

The clinic sample included Canadian patients and the online sample included primarily American patients. Due to differences, groups were examined separately. Almost 50% of respondents reported using cannabis (clinic n = 49; online n = 89). Of the cannabis users, 36.8% of clinic and 75% of online respondents reported that it improved their symptoms. Most of the respondents (from the clinic and online groups) reported that cannabis improved their mood, pain, muscle spasms, and sleep. However, they did not note any improvements for weakness, fatigue, numbness, ambulation, and urination. Overall, the effectiveness of cannabis for CP/CPPS was "somewhat/very effective" (57% clinic; 63% online). There were no differences between side effects or choice of consumption and most reported using cannabis rarely.

CONCLUSIONS

These are the first estimates in men suffering from CP/CPPS and suggest that while cannabis use is prevalent, its medical use and benefit are unknown. This is an understudied area and the benefit or hazard for cannabis use awaits further study.

NMP-7 inhibits chronic inflammatory and neuropathic pain via block of Cav3.2 T-type calcium channels and activation of CB2 receptors

Background

T-type calcium channels and cannabinoid receptors are known to play important roles in chronic pain, making them attractive therapeutic targets. We recently reported on the design, synthesis and analgesic properties of a novel T-type channel inhibitor (NMP-7), which also shows mixed agonist activity on CB₁ and CB₂ receptors in vitro. Here, we analyzed the analgesic effect of systemically delivered NMP-7 (intraperitoneal (i.p.) or intragstric (i.g.) routes) on mechanical hypersensitivity in inflammatory pain induced by Complete Freund’s Adjuvant (CFA) and neuropathic pain induced by sciatic nerve injury.

Results

NMP-7 delivered by either i.p. or i.g. routes produced dose-dependent inhibition of mechanical hyperalgesia in mouse models of inflammatory and neuropathic pain, without altering spontaneous locomotor activity in the open-field test at the highest active dose. Neither i.p. nor i.g. treatment reduced peripheral inflammation per se, as evaluated by examining paw edema and myeloperoxidase activity. The antinociception produced by NMP-7 in the CFA test was completely abolished in Ca_V3.2-null mice, confirming Ca_V3.2 as a key target. The analgesic action of intraperitoneally delivered NMP-7 was not affected by pretreatment of mice with the CB₁ antagonist AM281, but was significantly attenuated by pretreatment with the CB₂ antagonist AM630, suggesting that CB₂ receptors, but not CB₁ receptors are involved in the action of NMP-7 in vivo.

Conclusions

Overall, our work shows that NMP-7 mediates a significant analgesic effect in a model of persistent inflammatory and chronic neuropathic pain by way of T-type channel modulation and CB₂ receptor activation. Thus, this study provides a novel therapeutic avenue for managing chronic pain conditions via mixed CB ligands/T-type channel blockers.

Analgesic effect of a mixed T-type channel inhibitor/CB2 receptor agonist

BACKGROUND

Cannabinoid receptors and T-type calcium channels are potential targets for treating pain. Here we report on the design, synthesis and analgesic properties of a new mixed cannabinoid/T-type channel ligand, NMP-181.

RESULTS

NMP-181 action on CB1 and CB2 receptors was characterized in radioligand binding and in vitro GTPγ[35S] functional assays, and block of transiently expressed human Cav3.2 T-type channels by NMP-181 was analyzed by patch clamp. The analgesic effects and in vivo mechanism of action of NMP-181 delivered spinally or systemically were analyzed in formalin and CFA mouse models of pain. NMP-181 inhibited peak CaV3.2 currents with IC50 values in the low micromolar range and acted as a CB2 agonist. Inactivated state dependence further augmented the inhibitory action of NMP-181. NMP-181 produced a dose-dependent antinociceptive effect when administered either spinally or systemically in both phases of the formalin test. Both i.t. and i.p. treatment of mice with NMP-181 reversed the mechanical hyperalgesia induced by CFA injection. NMP-181 showed no antinocieptive effect in CaV3.2 null mice. The antinociceptive effect of intrathecally delivered NMP-181 in the formalin test was reversed by i.t. treatment of mice with AM-630 (CB2 antagonist). In contrast, the NMP-181-induced antinociception was not affected by treatment of mice with AM-281 (CB1 antagonist).

CONCLUSIONS

Our work shows that both T-type channels as well as CB2 receptors play a role in the antinociceptive action of NMP-181, and also provides a novel avenue for suppressing chronic pain through novel mixed T-type/cannabinoid receptor ligands.

Nabilone for the treatment of medication overuse headache: results of a preliminary double-blind, active-controlled, randomized trial

Medication overuse headache (MOH) is a severe burden to sufferers and its treatment has few evidence-based indications. The aim of this study is to evaluate efficacy and safety of nabilone in reducing pain and frequency of headache, the number of analgesic intake and in increasing the quality of life on patients with long-standing intractable MOH. Thirty MOH patients were enrolled at the University of Modena’s Interdepartmental Centre for Research on Headache and Drug Abuse (Italy) in a randomized, double-blind, active-controlled, crossover study comparing nabilone 0.5 mg/day and ibuprofen 400 mg. The patients received each treatment orally for 8 weeks (before nabilone and then ibuprofen or vice versa), with 1 week wash-out between them. Randomization and allocation (ratio 1:1) were carried out by an independent pharmacy through a central computer system. Participants, care givers, and those assessing the outcomes were blinded to treatment sequence. Twenty-six subjects completed the study. Improvements from baseline were observed with both treatments. However, nabilone was more effective than ibuprofen in reducing pain intensity and daily analgesic intake (p < 0.05); moreover, nabilone was the only drug able to reduce the level of medication dependence (−41 %, p < 0.01) and to improve the quality of life (p < 0.05). Side effects were uncommon, mild and disappeared when nabilone was discontinued. This is the first randomized controlled trial demonstrating the benefits of nabilone on headache, analgesic consumption and the quality of life in patients with intractable MOH. This drug also appears to be safe and well-tolerated. Larger scale studies are needed to confirm these preliminary findings.