A preliminary evaluation of the relationship of cannabinoid blood concentrations with the analgesic response to vaporized cannabis

Biphasic effects of cannabis and cannabinoid therapy on pain severity, anxiety, and sleep disturbance: a scoping review

INTRODUCTION

Cannabinoids are being used by patients to help with chronic pain management and to address the 2 primary chronic pain comorbidities of anxiety and sleep disturbance. It is necessary to understand the biphasic effects of cannabinoids to improve treatment of this symptom triad.

METHODS

A scoping review was conducted to identify whether biphasic effects of cannabinoids on pain severity, anxiolysis, and sleep disturbance have been reported. The search included the Embase, Biosis, and Medline databases of clinical literature published between 1970 and 2021. The inclusion criteria were (1) adults more than 18 years of age, (2) data or discussion of dose effects associated with U-shaped or linear dose responses, and (3) measurements of pain and/or anxiety and/or sleep disturbance. Data were extracted by 2 independent reviewers (with a third reviewer used as a tiebreaker) and subjected to a thematic analysis.

RESULTS

After the database search and study eligibility assessment, 44 publications met the final criteria for review. Eighteen publications that specifically provided information on dose response were included in the final synthesis: 9 related to pain outcomes, 7 measuring anxiety, and 2 reporting sleep effects.

CONCLUSIONS

This scoping review reports on biphasic effects of cannabinoids related to pain, sleep, and anxiety. Dose-response relationships are present, but we found gaps in the current literature with regard to biphasic effects of cannabinoids in humans. There is a lack of prospective research in humans exploring this specific relationship.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Variable Delta-9-Tetrahydrocannabinol Pharmacokinetics and Pharmacodynamics After Cannabis Smoking in Regular Users

BACKGROUND

Despite its federally restricted status, cannabis is widely used medicinally and recreationally. The pharmacokinetics (PK) and central nervous system (CNS) effects of tetrahydrocannabinol (THC), the major psychoactive cannabinoid, are not well understood. The objective of this study was to develop a population PK model of inhaled THC, including sources of variability, and to conduct an exploratory analysis of potential exposure-response relationships.

METHODS

Regular adult cannabis users smoked a single cannabis cigarette containing 5.9% THC (Chemovar A) or 13.4% THC (Chemovar B) ad libitum. THC concentrations in whole blood were measured and used to develop a population PK model to identify potential factors contributing to interindividual variability in THC PK and to describe THC disposition. Relationships between model-predicted exposure and heart rate, change in composite driving score on a driving simulator, and perceived highness were evaluated.

RESULTS

From the 102 participants, a total of 770 blood THC concentrations were obtained. A two-compartment structural model adequately fit the data. Chemovar and baseline THC (THC BL ) were found to be significant covariates for bioavailability, with Chemovar A having better THC absorption. The model predicted that heavy users-those with the highest THC BL -would have significantly higher absorption than those with lighter previous use. There was a statistically significant relationship between exposure and heart rate, and exposure and perceived highness.

CONCLUSIONS

THC PK is highly variable and related to baseline THC concentrations and different chemovars. The developed population PK model showed that heavier users had higher THC bioavailability. To better understand the factors affecting THC PK and dose-response relationships, future studies should incorporate a wide range of doses, multiple routes of administration, and different formulations relevant to typical community use.

Utilization of Physiologically Based Pharmacokinetic Modeling in Pharmacokinetic Study of Natural Medicine: An Overview

Natural medicine has been widely used for clinical treatment and health care in many countries and regions. Additionally, extracting active ingredients from traditional Chinese medicine and other natural plants, defining their chemical structure and pharmacological effects, and screening potential druggable candidates are also uprising directions in new drug research and development. Physiologically based pharmacokinetic (PBPK) modeling is a mathematical modeling technique that simulates the absorption, distribution, metabolism, and elimination of drugs in various tissues and organs in vivo based on physiological and anatomical characteristics and physicochemical properties. PBPK modeling in drug research and development has gradually been recognized by regulatory authorities in recent years, including the U.S. Food and Drug Administration. This review summarizes the general situation and shortcomings of the current research on the pharmacokinetics of natural medicine and introduces the concept and the advantages of the PBPK model in the study of pharmacokinetics of natural medicine. Finally, the pharmacokinetic studies of natural medicine using the PBPK models are summed up, followed by discussions on the applications of PBPK modeling to the enzyme-mediated pharmacokinetic changes, special populations, new drug research and development, and new indication adding for natural medicine. This paper aims to provide a novel strategy for the preclinical research and clinical use of natural medicine.

Online survey of medicinal cannabis users: Qualitative analysis of patient-level data

Aim: To characterize perceived benefits and challenges experienced by medicinal cannabis users.

Methods: An anonymous online survey collected demographics, health information, and open-ended responses from medicinal cannabis users regarding perceptions, motivations, and experience of treatment. Qualitative open-ended responses were thematically analyzed.

Results: Respondents (N = 808) were predominantly White (79%), female (63%), with a mean (SD) age of 38 (20). Two hundred eighty-four (35%) respondents provided data on a dependent family member (e.g., child; 22% of total sample). Most used cannabidiol (CBD)-dominant products (58%), primarily for neurological disorders (38%) or pain (25%). Primary motivations for medicinal cannabis use were based on beliefs that traditional treatments were ineffective and/or had intolerable side effects (51%), positive scientific or media portrayals of the safety/efficacy of cannabis as a therapeutic (29%), or preference for “natural” treatments over pharmaceuticals (21%). A majority of respondents (77%) attributed positive effects to the medicinal use of cannabis/cannabinoids. These included physical symptom improvements such as reduced pain (28%), improved sleep (18%), and seizure reduction (18%), and mental health improvements including reduced anxiety (22%) and improved mood (11%). Additionally, respondents reported reduced use of other medications (e.g., opioids) (12%), and improved quality of life (14%). Problems associated with use were cited by 41% of respondents, and included unwanted side effects (16%), lack of information or medical support (16%), prohibitive costs (12%), and legal concerns (10%).

Conclusion: Most participants reported benefits from cannabis use for a variety of conditions where traditional treatments were ineffective or unacceptable. Concerns regarding cannabis side effects, legality, lack of information, and cost were raised. Data indicate greater research and education on the safety and efficacy of medicinal cannabis/cannabinoid use is warranted.

A scoping review on the effect of cannabis on pain intensity in people with spinal cord injury

CONTEXT

This scoping review examines the current research on the effect of cannabis upon pain intensity in spinal cord injury (SCI) pain. Chronic pain is a significant secondary condition following SCI, and traditional treatments (e.g. opioids, NSAIDs) are often criticized for providing inadequate relief. As a result, there is increasing interest in and use of cannabis and cannabinoid-based medications as an alternative means of pain control.

OBJECTIVE

The purpose of this review was to examine the scientific evidence on the effect of cannabis/cannabinoids upon pain intensity in SCI by mapping the current literature.

METHODS

Two hundred and fifty-two studies were identified by searching electronic databases for articles published through February 2020. In addition, reviewers scanned the reference lists of identified articles and examined clinicaltrials.gov for unpublished data in this area. Title, abstract, and full-text reviews were completed by two independent reviewers. Data extraction was performed by a single reviewer and verified by a second reviewer.

RESULTS

Six articles covering five treatment studies were included. Studies yielded mixed findings likely due to large variability in methodology, including lack of standardized dosing paradigms, modes of use, and duration of trial.

CONCLUSIONS

The current quality and level of evidence is insufficient to draw reliable conclusions of the efficacy of cannabis upon SCI-related pain itensity. We identify specific limitations of past studies and present guidelines for future research.Trial registration: ClinicalTrials.gov identifier: Nct01606202..

The Efficacy of Cannabis in Reducing Back Pain: A Systematic Review

OBJECTIVE

To critically analyze the evidence and efficacy of cannabis to treat surgical and nonsurgical back pain via a Systematic Review.

METHODS

We conducted a systematic review to investigate the efficacy of cannabis to treat non-surgical and surgical back pain. A literature search was performed with MEDLINE and Embase databases. Only RCTs and prospective cohort studies with concurrent control were included in this study. Risk of bias and quality grading was assessed for each included study.

RESULTS

Database searches returned 1738 non-duplicated results. An initial screening excluded 1716 results. Twenty-two full text articles were assessed for eligibility. Four articles ultimately met pre-determined eligibility and were included in the study. Two studies addressed post-SCI pain while other two studies addressed low back pain. No studies specifically examined the use of cannabis for surgical back pain. The type of cannabis varied between study and included THC, dronabinol, and Nabilone. A total of 110 patients were included in the four studies reviewed. In each study, there was a quantifiable advantage of cannabis therapy for alleviating back pain. There were no serious adverse effects reported.

CONCLUSIONS

In all articles, cannabis was shown to be effective to treat back pain with an acceptable side effect profile. However, long-term follow up is lacking. As medicinal cannabis is being used more commonly for analgesic effect and patients are "self-prescribing" cannabis for back pain, additional studies are needed for healthcare providers to confidently recommend cannabis therapy for back pain.

STUDY DESIGN

Systematic review.

Exploring cannabis use and perspectives among psoriatic disease patients

OBJECTIVE

To assess the correlation between cannabis use and psoriatic disease severity, health-related quality of life, pain, psychosocial outcomes, and cytokine levels in psoriasis (PsC) and psoriatic arthritis (PsA) patients.

METHODS

PsC and PsA patients enrolled in the International Psoriasis and Arthritis Research Team (IPART) program were surveyed on cannabis use and were asked to provide a serum and urine sample. Demographic and clinical variables were compared between users and non-users using Student's t-test or Mann-Whitney U test for continuous variables, and chi-square or Fisher's exact test for categorical variables.

RESULTS

Of 151 respondents, 30% reported current cannabis use within the last year. Compared to non-users, cannabis users were younger and had a shorter PsA duration and poorer mental health as measured by the SF-36. Other measures of health-related quality of life and pain were comparable between the groups. Respondents' primary perceived benefits of cannabis use were aid in sleep and arthritis pain relief, but there was no difference in pain between users and non-users. No THC was detected in the urine of non-users while users had a mean level of 19.6 ng/ml. Serum IL-23 levels were statistically significantly higher in non-users than in users.

CONCLUSION

A third of the patients used cannabis within the past year, and 54.3% of users reported the use of cannabis for arthritis pain relief. However, there was no difference in pain scores. Comprehensive education for providers on the current body of evidence and further studies on cannabis use and outcomes in psoriatic disease are needed. Key Points • A third of patients with psoriatic arthritis have used cannabis in the past year. • Most used it for better sleep and control of pain. • There was no difference in pain scores between users and non-users. • IL-23 levels were significantly higher in non-users.

UK Medical Cannabis registry: an analysis of clinical outcomes of medicinal cannabis therapy for chronic pain conditions

OBJECTIVES

To explore pain-specific, general health-related quality of life (HRQoL), and safety outcomes of chronic pain patients prescribed cannabis-based medicinal products (CBMPs).

METHODS

A case series was performed using patients with chronic pain from the UK Medical Cannabis Registry. Primary outcomes were changes in Brief Pain Inventory short-form (BPI), Short-form McGill Pain Questionnaire-2 (SF-MPQ-2), Visual Analogue Scale-Pain (VAS), General Anxiety Disorder-7 (GAD-7), Sleep Quality Scale (SQS), and EQ-5D-5L, at 1, 3, and 6 months from baseline. Statistical significance was defined at p-value<0.050.

RESULTS

190 patients were included. Median initial Δ⁹-tetrahydrocannabinol and cannabidiol daily doses were 2.0mg (range:0.0-442.0mg) and 20.0mg (range:0.0-188.0mg) respectively. Significant improvements were observed within BPI, SF-MPQ-2, GAD-7, SQS, EQ-5D-5 L index, and VAS measures at all timepoints (p<0.050). Seventy-five adverse events (39.47%) were reported, of which 37 (19.47%) were rated as mild, 23 (12.11%) as moderate, and 14 (7.37%) as severe. Nausea (n=11; 5.8%) was the most frequent adverse event.

CONCLUSION

An association was identified between patients with chronic pain prescribed CBMPs and improvements in pain-specific and general HRQoL outcomes. Most adverse events were mild to moderate in severity, indicating CBMPs were well tolerated. Inherent limitations of study design limit its overall applicability.

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.

Medicinal Applications of Cannabinoids Extracted from Cannabis sativa (L.): A New Route in the Fight Against COVID-19?

Cannabis sativa is a well-known plant that has been recognized for its benefits since ancient times by several medicinal systems, including those of China, India, Greece, and Egypt. Although C. sativa is one of the most investigated medicinal plants in the world, it faces some of the greatest controversies surrounding its legalization and use as a medication. C. sativa contains several hundred phytoconstituents, including the infamous "cannabinoids". It is necessary to properly understand the medicinal importance of these phytochemicals and spread awareness among the countries where cannabis is still facing legal obstacles. The current review focuses on the most recent literature pertaining to various applications of cannabinoids, with a special focus on the medicinal aspect of these phytochemicals. Peer-reviewed articles focusing on the importance of cannabis and cannabinoids are the target of this review. Articles were selected based on the relevance to the general scope of the work, i.e., application of cannabinoids. Cannabinoids can truly be regarded as wonder drugs, considering their immense diversity of usage. Unfortunately, however, many of the mares have never been researched biologically or pharmacologically due to their low yield in the plant. However, the approval of some cannabinoids by the FDA (along with other recognized national medical health systems) has opened the horizon for the use of these natural drugs in medicines such as Epidiolex® (cannabidiol, used for the treatment of severe forms of epilepsy) and Sativex®(Δ⁹-tetrahydrocannabinol and cannabidiol, used for the treatment of spasticity caused by multiple sclerosis). Many pharmacological properties of C. sativa are attributed to cannabidiol (CBD), a non-psychoactive component, along with Δ9-tetrahydrocannabinol (Δ⁹-THC), a psychoactive component. This review addresses the most important applications or current utilization of cannabinoids in a variety of treatments such as chronic pain, cancer, emesis, anorexia, irritable bowel syndrome, communicable diseases, glaucoma, and central nervous system disorders. The biosynthetic pathway of cannabinoids is also discussed. In short, cannabis has a myriad of bioactive compounds that have the potential to increase the list of approved cannabinoids suitable for therapy.

Using Therapeutic Drug Monitoring and Pharmacovigilance to Overcome Some of the Challenges of Developing Medicinal Cannabis from Botanical Origins

PURPOSE

Plants belonging to the genus Cannabis have been domesticated and used by humans for millennia. Thought to have originated from central Asia, cannabis has been harnessed for its nutritional, therapeutic, and psychoactive properties, and as a source of fiber (Office of Medicinal Cannabis. Analytical Monograph Cannabis Flos. Den Haag, The Netherlands: Office of Medicinal Cannabis; 2014). Human use of cannabis is not novel; however, its medicalization offers a new pharmacotherapeutic frontier.

METHODS

The authors recently reported a systematic review of the contaminants of cannabis (National Academies of Sciences Engineering, and Medicine. The health effects of cannabis and cannabinoids: the current state of evidence and recommendations for research. Washington, DC; 2017). This article draws on the research limitations identified by that review and examines a collection of the relevant literature to provide an appreciation of the current evidence base.

RESULTS

The review explores the current status of cannabis in medical use, the drug development aspects that apply when taking a plant through to pill development, and the roles that therapeutic drug monitoring and pharmacovigilance have to guide practice until the drug development information on medicinal cannabis preparations is complete.

CONCLUSIONS

A surge of public and clinical interest in the possible therapeutic applications of constituent cannabinoids has potentiated global legislative and policy reform. However, our understanding of its properties, optimized use, and harmful effects remains incomplete (Therapeutic Goods Administration. Guidance for the use of medicinal cannabis in Australia In: Department of Health Department, editor. Woden ACT Australian Government 2017; Dryburgh LM, Bolan NS, Grof CP, Galettis P, Schneider J, Lucas CJ, et al. Cannabis contaminants: sources, distribution, human toxicity and pharmacologic effects. Brit J Clin Pharm. 2018;84(11):2468-2476). In particular, a comprehensive appreciation of its toxicity profile is lacking.

Disposition of Phytocannabinoids, Their Acidic Precursors and Their Metabolites in Biological Matrices of Healthy Individuals Treated with Vaporized Medical Cannabis

Inhalation by vaporization is a useful application mode for medical cannabis. In this study, we present the disposition of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), their acidic precursors, and their metabolites in serum, oral fluid, and urine together with the acute pharmacological effects in 14 healthy individuals treated with vaporized medical cannabis. THC and CBD peaked firstly in serum and then in oral fluid, with higher concentrations in the first biological matrices and consequent higher area under the curve AUCs. Acidic precursors Δ-9-tetrahydrocannabinolic acid A (THCA) and cannabidiolic acid (CBDA) showed a similar time course profile but lower concentrations due to the fact that vaporization partly decarboxylated these compounds. All THC and CBD metabolites showed a later onset with respect to the parent compounds in the absorption phase and a slower decrease to baseline. In agreement with serum kinetics, THC-COOH-GLUC and 7-COOH-CBD were the significantly most excreted THC and CBD metabolites. The administration of vaporized medical cannabis induced prototypical effects associated with the administration of cannabis or THC in humans, with a kinetic trend overlapping that of parent compounds and metabolites in serum. The pharmacokinetics of cannabinoids, their precursors, and their metabolites in biological fluids of individuals treated with vaporized medical cannabis preparations showed a high interindividual variability as in the case of oral medical cannabis decoction and oil. Inhaled medical cannabis was absorbed into the organism earlier than decoction and oil. Cannabinoids reached higher systemic concentrations, also due to the fact that the acid precursors decarboxylated to parent cannabinoids at high temperatures, and consequently, the physiological and subjective effects occurred earlier and resulted with higher intensity. No serious adverse effects were observed.

CBD and THC: Do They Complement Each Other Like Yin and Yang?

Increased public access to cannabis calls for a deeper understanding of cannabis's constituents and how they interact to induce clinical effects. Whereas trans-Δ⁹ -tetrahydrocannabinol (THC) is considered the main psychoactive component in cannabis, producing the associated "high" or "euphoria," various findings demonstrate medical potential for cannabidiol (CBD), from anxiolytic to antiepileptic implications. This has translated into a public optimism and given way to the popular opinion that CBD can provide countless other therapeutic benefits, including the potential to mitigate some of the adverse side effects of THC, such as intoxication, psychomotor impairment, anxiety, and psychotic symptoms. This is particularly relevant for patients seeking to garner therapeutic benefits from cannabis without experiencing the burden of a significant subjective high. Thus, this article analyzes the scientific evidence available to support or disprove the idea that presence of CBD is beneficial and can exude a protective effect against THC. A thorough review of relevant literature, a basis from which to interpret such evidence through a critical mechanistic discussion, and the implications for patients are presented in this article.

Minimal Physiologically Based Pharmacokinetic Model of Intravenously and Orally Administered Delta-9-Tetrahydrocannabinol in Healthy Volunteers

BACKGROUND AND OBJECTIVES

Lack of information on the pharmacokinetics of the active moiety of Cannabis or the metabolites of delta-9-tetrahydrocannabinol (THC) does not seem to be discouraging medical or recreational use. Cytochrome P450 (CYP) 2C9, the primary enzyme responsible for THC metabolism, has two single nucleotide polymorphisms-Arg144Cys (*2) and Ile359Leu (*3). In the Caucasian population, allelic frequency is between 0.08 and 0.14 for CYP2C9*2 and between 0.04 and 0.16 for CYP2C9*3. In vitro data suggest that metabolic capacity for the variants CYP2C9*2 and CYP2C9*3 is about one-third compared to wild-type CYP2C9. Previous work has suggested exposure to the terminal metabolite is genetically determined. We therefore sought to characterize the pharmacokinetics of THC and its major metabolites 11-hydroxy-delta-9-tetrahydrocannabinol (THC-OH) and 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH) in healthy volunteers with known CYP2C9 status by non-compartmental analysis (NCA), compartmental modeling (CM) and minimal physiologically based pharmacokinetic (mPBPK) modeling.

METHODS

Blood samples drawn for THC, THC-OH and THC-COOH after a single intravenous (IV) bolus of 0.1 mg/kg (0.32 μM/kg) THC were analyzed using a validated LC-MS/MS method. NCA generated initial estimates and CM and the mPBPK model were then fit to plasma concentration data using non-linear mixed-effects modeling. Blood samples from orally dosed (10, 25 and 50 mg) THC brownies were added to validate the model.

RESULTS

THC can be described as a high hepatic extraction ratio drug with blood flow-dependent metabolism not restricted by protein binding. THC hepatic clearance is dependent on the CYP2C9 genetic variant in the population. High extraction drugs display route-dependent metabolism. When administered via the IV or inhalation routes, induction or inhibition of CYP2C9 should be non-contributory as the elimination of THC is dependent only on liver blood flow. THC-OH is also a high extraction ratio drug, but its hepatic clearance is significantly impacted by the hepatic diffusional barrier that impedes its access to hepatic CYP2C9. THC-COOH is glucuronidated and renally cleared; subjects homozygous for CYP2C9*3 have reduced exposure to this metabolite as a result of the polymorphism reducing THC production, the hepatic diffusional barrier impeding egress from the hepatocyte, and increased renal clearance.

CONCLUSION

It has recently been reported that the terminal metabolite THC-COOH is active, implying the exposure difference in individuals homozygous for CYP2C9*3 may become therapeutically relevant. Defining the metabolism of THC in humans is important, as it is increasingly being used as a drug to treat various diseases and its recreational use is also rising. We have used NCA, CM, and mPBPK modeling of THC and its metabolites to partially disentangle the complexity of cannabis disposition in humans.

A phase 1, randomized, pharmacokinetic trial of the effect of different meal compositions, whole milk, and alcohol on cannabidiol exposure and safety in healthy subjects

OBJECTIVE

The pharmacokinetics (PK) and safety of single oral 750-mg doses of a plant-derived pharmaceutical formulation of highly purified cannabidiol (CBD; Epidiolex in the USA and Epidyolex in Europe; 100-mg/mL oral solution) were assessed in healthy adults following a high-fat/calorie meal (n = 15), a low-fat/calorie meal (n = 14), whole milk (n = 15), or alcohol (n = 14), relative to the fasted state (n = 29).

METHODS

Blood samples were collected until 96 hours postdose in each period and evaluated by liquid chromatography and tandem mass spectrometry. PK parameters (maximum observed plasma concentration [C_max ], area under the plasma concentration-time curve from time zero to the last observed quantifiable concentration, area under the concentration-time curve from time zero to infinity [AUC_0-∞ ], and time to maximum plasma concentration [t_max ]) of CBD and its major metabolites were derived using noncompartmental analysis.

RESULTS

CBD exposure increased by 3.8-fold for AUC_0-∞ and 5.2-fold for C_max when CBD was administered with a high-fat/calorie meal versus fasted. To a lesser extent, a low-fat/calorie meal enhanced CBD exposure versus fasted with a 2.7-fold increase in AUC_0-∞ and a 3.8-fold increase in C_max . Similarly, when dosed with whole milk, CBD exposure increased versus fasted by 2.4-fold for AUC_0-∞ and 3.1-fold for C_max . Modest elevations in CBD exposure occurred when it was dosed with alcohol: 1.6-fold for AUC_0-∞ and 1.9-fold for C_max . No clinically relevant effect of any test condition on CBD t_max or t_½ versus the fasted state was apparent. The same trend was seen for the CBD metabolites, except that 7-carboxy-cannabidiol t_max was considerably longer when CBD was administered with alcohol (14 vs 4 hours fasted). Inter- and intrasubject variability in PK parameters was moderate to high during the trial.

SIGNIFICANCE

CBD and metabolite exposures were most affected by a high-fat/calorie meal. CBD exposures also increased with a low-fat/calorie meal, whole milk, or alcohol, but to a lesser extent. CBD was tolerated, and there were no severe or serious adverse events during the trial.

A Preliminary Study of Associations between Discomfort Intolerance, Pain Severity/Interference, and Frequency of Cannabis Use among Individuals with Chronic Pain

Cannabis use is more common among individuals with chronic pain, and is often used to relieve physical discomfort. However, little is known about factors that are associated with cannabis use among individuals with chronic pain, and there is reason to suspect that perceptions of discomfort intolerance (DI) play an important role in pain-cannabis relations. The goal of this study was to conduct an initial examination of perceived DI, pain severity, and pain-related interference in relation to frequency of cannabis use among individuals with chronic pain. Specifically, we hypothesized that pain severity/interference and factors of DI (avoidance and intolerance), would each be positively associated with cannabis use frequency. Participants (N = 109; 44% male; M _age = 27) endorsed chronic pain and at least one instance of lifetime cannabis use. Most participants characterized their chronic pain as high intensity and low disability, and the two most commonly reported frequencies of cannabis use were "less than monthly" (n = 38), and "daily/almost daily" (n = 32). Results indicated that discomfort avoidance (but not discomfort intolerance), pain severity, and pain-related interference were each independently and positively associated with frequency of cannabis use. These preliminary findings suggest that continued examination of perceived discomfort avoidance in relation to co-occurring pain and cannabis use is warranted. Future research should replicate these results among treatment-seeking pain patients who are prescribed medical cannabis.

A Phase 1, Open-Label, Parallel-Group, Single-Dose Trial of the Pharmacokinetics and Safety of Cannabidiol (CBD) in Subjects With Mild to Severe Hepatic Impairment

The pharmacokinetics and safety of a single oral dose of 200-mg plant-derived pharmaceutical formulation of highly purified cannabidiol (CBD) in oral solution (Epidiolex in the United States; 100 mg/mL) were assessed in subjects with mild to severe hepatic impairment (n =  8 each for mild and moderate, n = 6 for severe) relative to matched subjects with normal hepatic function (n = 8). Blood samples were collected until 48 hours after dosing and evaluated by liquid chromatography and tandem mass spectrometry. Pharmacokinetic parameters (primarily maximum measured plasma concentration, area under the plasma concentration-time curve from time zero to time t, area under the concentration-time curve from time zero to infinity, time to maximum plasma concentration, and terminal half-life) of CBD and its major metabolites were derived using non-compartmental analysis. CBD was rapidly absorbed in all groups independent of hepatic function (median time to maximum plasma concentration, 2-2.8 hours). Exposure (area under the concentration-time curve from time zero to infinity) to total CBD slightly increased in subjects with mild hepatic impairment (geometric mean ratio [GMR], 1.48; 90% confidence interval [CI], 0.90-2.41). However, there were clinically relevant increases in subjects with moderate (GMR, 2.45; 90%CI, 1.50-4.01) and severe (GMR, 5.15; 90%CI, 2.94-9.00) hepatic impairment, relative to subjects with normal hepatic function. Exposure to the CBD metabolites (6-hydroxy-CBD and 7-hydroxy-CBD) also increased in subjects with moderate and severe hepatic impairment, but to a lesser extent than the parent drug. The 7-carboxy-CBD metabolite exposure was lower in subjects with severe hepatic impairment when compared with subjects with normal liver function. These findings indicate that dose modification is necessary in patients with moderate and severe hepatic impairment, and a lower starting dose and slower titration are necessary based on benefit-risk. CBD was well tolerated, and there were no serious adverse events reported during the trial.

Utilization of medicinal cannabis for pain by individuals with spinal cord injury

Study design

A cross-sectional multi-center study using an on-line survey addressing utilization, knowledge, and perceptions of medicinal cannabis (MC) by people with spinal cord injury (SCI).

Objective

To characterize differences between current (CU), past (PU), and never users (NU) of MC with SCI; to determine why people with SCI use MC; to examine reports of MCs' efficacy and tolerability by individuals with SCI.

Setting

Three academic medical centers in the United States.

Methods

Comparison of demographic and attitudinal differences between CU, PU, and NU and differences in the groups' reports of pain, health, and quality of life (QOL). Evaluation of utilization patterns and perceived efficacy of MC among CU and PU and reports of side effects of MC versus prescription medications. Data were analyzed using either Chi Square, distribution-free exact statistics, or t-tests for continuous data.

Results

Among a nationwide sample (n = 353) of individuals with SCI, NU were less likely than CU and PU to believe that cannabis ought to be legalized and more likely to endorse risks of use. Current users and PU reported greater pain interference in daily life than did NU, but there were no between group differences in QOL or physical or emotional health. Current users and PU took MC to address pain (65.30%), spasms (63.30%), sleeplessness (32.70%), and anxiety (24.00%), and 63.30% reported it offered "great relief" from symptoms. Participants reported that MC is more effective and carries fewer side effects than prescription medications.

Conclusions

Medicinal cannabis is an effective and well-tolerated treatment for a number of SCI-related symptoms.

Crossing the Line: Care of a Pediatric Patient with Intractable Seizures and Severe Neuropathic Pain in Absence of Access to Medical Marijuana

Background: A reality of the current political and legal environment is that while marijuana and cannabis-based products remain not approved for human consumption at the federal level in the United States, several states have authorized use for constituents. While state lines represent meaningful cultural and geographical identity markers, the reality is that patients and families readily cross state lines to access medical interventions and care. Methods: We present the case of a six-year-old child with intractable seizures and severe neuropathic pain managed on medical marijuana (MM) in her home state of Colorado; where medicinal use of marijuana is authorized at the state level; traveling across state lines to access surgical care in Nebraska where MM is prohibited. Conclusion: The case report shares the communication and creativity invested in adequate symptom management for this child weaned off of MM perioperatively. The case recognizes the unique complexities of shared symptom management goals within state-specific care models.

Cannabinoids: Current and Future Options to Treat Chronic and Chemotherapy-Induced Neuropathic Pain

Increases in cancer diagnosis have tremendous negative impacts on patients and their families, and major societal and economic costs. The beneficial effect of chemotherapeutic agents on tumor suppression comes with major unwanted side effects such as weight and hair loss, nausea and vomiting, and neuropathic pain. Chemotherapy-induced peripheral neuropathy (CIPN), which can include both painful and non-painful symptoms, can persist 6 months or longer after the patient's last chemotherapeutic treatment. These peripheral sensory and motor deficits are poorly treated by our current analgesics with limited effectiveness. Therefore, the development of novel treatment strategies is an important preclinical research focus and an urgent need for patients. Approaches to prevent CIPN have yielded disappointing results since these compounds may interfere with the anti-tumor properties of chemotherapeutic agents. Nevertheless, the first (serotonin noradrenaline reuptake inhibitors [SNRIs], anticonvulsants, tricyclic antidepressants) and second (5% lidocaine patches, 8% capsaicin patches and weak opioids such as tramadol) lines of treatment for CIPN have shown some efficacy. The clinical challenge of CIPN management in cancer patients and the need to target novel therapies with long-term efficacy in alleviating CIPN are an ongoing focus of research. The endogenous cannabinoid system has shown great promise and efficacy in alleviating CIPN in preclinical and clinical studies. In this review, we will discuss the mechanisms through which the platinum, taxane, and vinca alkaloid classes of chemotherapeutics may produce CIPN and the potential therapeutic effect of drugs targeting the endocannabinoid system in preclinical and clinical studies, in addition to cannabinoid compounds diffuse mechanisms of action in alleviation of CIPN.

The level of evidence of medical marijuana use for treating disabilities: a scoping review

Purpose: Twenty-nine states have bypassed federal regulations by legalizing marijuana (MJ) either medicinally, recreationally or both. The FDA states that there is no empirical evidence that MJ is effective to treat these disorders. With over a billion individuals living with a disability across the globe, it is crucial to fully research the efficaciousness and safety of medical MJ to treat this population. The purpose to present the results of a scoping review of studies focused on the levels of evidence currently available on medical MJ's efficacy in treatment across a large range of disabilities.Methods: Databases were searched for research articles on the current level of evidence to support medical MJ use among people with disabilities.Results: Forty-one peer reviewed articles met the inclusion criteria. Articles focused on attention deficit hyperactivity disorder, post-traumatic stress disorder, depression, schizophrenia, spinal cord injury, multiple sclerosis/movement disorders, fibromyalgia, epilepsy, with some that focused on multiple disabilities.Conclusions: The level of evidence for the use of medical MJ among people with disabilities varies greatly, and has a clear lack of methodologically sound studies. Overall, medical MJ does not improve the level of functioning, but it may improve the overall quality of life for people with disabilities.Implications for RehabilitationEpilepsy can be a disabling chronic disorder which not only impacts physically but can restricts quality of life.Quality of life is diminished even more with treatment resistant epilepsy.Chronic pain is the leading cause of disability and is the most common cause of long-term disability.There is sufficient evidence that medical marijuana is effective in treating epileptic seizures and chronic pain.Medical marijuana may improve the level of functioning and quality of life for individuals with certain disabilities.

Cannabinoids and Pain: New Insights From Old Molecules

Cannabis has been used for medicinal purposes for thousands of years. The prohibition of cannabis in the middle of the 20th century has arrested cannabis research. In recent years there is a growing debate about the use of cannabis for medical purposes. The term ‘medical cannabis’ refers to physician-recommended use of the cannabis plant and its components, called cannabinoids, to treat disease or improve symptoms. Chronic pain is the most commonly cited reason for using medical cannabis. Cannabinoids act via cannabinoid receptors, but they also affect the activities of many other receptors, ion channels and enzymes. Preclinical studies in animals using both pharmacological and genetic approaches have increased our understanding of the mechanisms of cannabinoid-induced analgesia and provided therapeutical strategies for treating pain in humans. The mechanisms of the analgesic effect of cannabinoids include inhibition of the release of neurotransmitters and neuropeptides from presynaptic nerve endings, modulation of postsynaptic neuron excitability, activation of descending inhibitory pain pathways, and reduction of neural inflammation. Recent meta-analyses of clinical trials that have examined the use of medical cannabis in chronic pain present a moderate amount of evidence that cannabis/cannabinoids exhibit analgesic activity, especially in neuropathic pain. The main limitations of these studies are short treatment duration, small numbers of patients, heterogeneous patient populations, examination of different cannabinoids, different doses, the use of different efficacy endpoints, as well as modest observable effects. Adverse effects in the short-term medical use of cannabis are generally mild to moderate, well tolerated and transient. However, there are scant data regarding the long-term safety of medical cannabis use. Larger well-designed studies of longer duration are mandatory to determine the long-term efficacy and long-term safety of cannabis/cannabinoids and to provide definitive answers to physicians and patients regarding the risk and benefits of its use in the treatment of pain. In conclusion, the evidence from current research supports the use of medical cannabis in the treatment of chronic pain in adults. Careful follow-up and monitoring of patients using cannabis/cannabinoids are mandatory.

Cannabis shenanigans: advocating for the restoration of an effective treatment of pain following spinal cord injury

Cannabis is an effective treatment for pain following spinal cord injury that should be available to patients and researchers. The major argument against the rescheduling of cannabis is that the published research is not convincing. This argument is disingenuous at best, given that the evidence has been presented and rejected at many points during the political dialog. Moreover, the original decision to criminalize cannabis did not utilize scientific or medical data. There is tension between the needs of a society to protect the vulnerable by restricting the rights of others to live well and with less pain. It is clear that this 70-year war on cannabis has had little effect in controlling the supply of cannabis. Prohibition can never succeed; "it is a tyranny from which every independent mind revolts." People living with chronic pain should not have to risk addiction, social stigma, restrictions on employment and even criminal prosecution in order to deal with their pain. It is time to end the shenanigans and have an open, transparent discussion of the true benefits of this much-beleaguered medicine.

Preferences for Medical Marijuana over Prescription Medications Among Persons Living with Chronic Conditions: Alternative, Complementary, and Tapering Uses

OBJECTIVES

Despite expanded legalization and utilization of medical cannabis (MC) internationally, there is a lack of patient-centered data on how MC is used by persons living with chronic conditions in tandem with or instead of prescription medications. This study describes approaches to use of MC vis-à-vis prescription medications in the treatment of selected chronic conditions.

DESIGN

Participants completed semistructured telephone interviews with open-ended questions. Content analysis of qualitative data identified themes and subthemes relating to patient approaches to using MC products.

PARTICIPANTS

Thirty persons (mean age = 44.6 years) living with a range of chronic conditions (e.g., rheumatoid arthritis, Crohn's disease, spinal cord injury/disease, and cancer) who had qualified for and used MC in Illinois.

RESULTS

Participants described a range of approaches to using MC, including (1) as alternatives to using prescription or over-the-counter medications; (2) complementary use with prescription medications; and (3) as a means for tapering off prescription medications. Motives reported for reducing or eliminating prescription medications included concerns regarding toxicity, dependence, and tolerance, and perceptions that MC improves management of certain symptoms and has quicker action and longer lasting effects.

CONCLUSIONS

MC appears to serve as both a complementary method for symptom management and treatment of medication side-effects associated with certain chronic conditions, and as an alternative method for treatment of pain, seizures, and inflammation in this population. Additional patient-centered research is needed to identify specific dosing patterns of MC products associated with symptom alleviation and produce longitudinal data assessing chronic disease outcomes with MC use.

Determination of Cannabinoid Vapor Pressures to Aid in Vapor Phase Detection of Intoxication

The quest for a reliable means to detect cannabis intoxication with a breathalyzer is ongoing. To design such a device, it is important to understand the fundamental thermodynamics of the compounds of interest. The vapor pressures of two important cannabinoids, cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (Δ⁹-THC), are presented, as well as the predicted normal boiling temperature (NBT) and the predicted critical constants (these predictions are dependent on the vapor pressure data). The critical constants are typically necessary to develop an equation of state (EOS). EOS-based models can provide estimations of thermophysical properties for compounds to aid in designing processes and devices. An ultra-sensitive, quantitative, trace dynamic headspace analysis sampling called porous layered open tubular-cryoadsorption (PLOT-cryo) was used to measure vapor pressures of these compounds. PLOT-cryo affords short experiment durations compared to more traditional techniques for vapor pressure determination (minutes versus days). Additionally, PLOT-cryo has the inherent ability to stabilize labile solutes because collection is done at reduced temperature. The measured vapor pressures are approximately 2 orders of magnitude lower than those measured for n-eicosane, which has a similar molecular mass. Thus, the difference in polarity of these molecules must be impacting the vapor pressure dramatically. The vapor pressure measurements are presented in the form of Clausius-Clapeyron (or van't Hoff) equation plots. The predicted vapor pressures that would be expected at near ambient conditions (25 °C) are also presented.

Cannabis and Pain: A Clinical Review

Introduction: Cannabis has been used for medical purposes across the world for centuries. As states and countries implement medical and recreational cannabis policies, increasing numbers of people are using cannabis pharmacotherapy for pain. There is a theoretical rationale for cannabis' efficacy for pain management, although the subjective pain relief from cannabis may not match objective measurements of analgesia. As more patients turn to cannabis for pain relief, there is a need for additional scientific evidence to evaluate this increase. Materials and Methods: Research for this review was performed in the PubMed/National Library of Medicine database. Discussion: Preclinical studies demonstrate a narrow therapeutic window for cannabis as pharmacotherapy for pain; the body of clinical evidence for this indication is not as extensive. A recent meta-analysis of clinical trials of cannabis and cannabinoids for pain found modest evidence supporting the use of cannabinoid pharmacotherapy for pain. Recent epidemiological studies have provided initial evidence for a possible reduction in opioid pharmacotherapy for pain as a result of increased implementation of medical cannabis regimens. Conclusion: With increased use of medical cannabis as pharmacotherapy for pain comes a need for comprehensive risk-benefit discussions that take into account cannabis' significant possible side effects. As cannabis use increases in the context of medical and recreational cannabis policies, additional research to support or refute the current evidence base is essential to attempt to answer the questions that so many healthcare professionals and patients are asking.