Non-smoker exposure to secondhand cannabis smoke II: Effect of room ventilation on the physiological, subjective, and behavioral/cognitive effects

Identifying standardised neuropsychological test measures sensitive to cannabis consumption: A systematic review

BACKGROUND

While numerous studies have indicated acute neurocognitive changes following the administration of Δ9-tetrahydrocannabinol (THC; the psychoactive component of cannabis), the standardised neuropsychological tests most sensitive to THC are yet to be identified. As such, this systematic review analysed scientific evidence (since 2000) on the effects of THC on standardised neuropsychological test measures.

METHODS

This review was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were eligible for inclusion if they utilised a between or within-subjects design in testing for differences in standardised neuropsychological test performance following the consumption of THC.

RESULTS/DISCUSSION

Sufficient data were identified to examine 8 standardised neuropsychological test measures, with 12 studies being eligible for inclusion in the review. It was identified that Cambridge Neuropsychological Test Automated Battery (CANTAB) subtest Spatial Working Memory, Hopkins Verbal Learning Test, Prose Recall and Rey Auditory Verbal Learning Test were sensitive to cannabis consumption.

LIMITATIONS

However, due to substantial variability observed across studies, the data could not be quantitatively analysed. It was noted that few studies employed standardised neuropsychological measures in assessing the effects of THC.

CONCLUSION

Overall, the findings highlight the need for further research examining the effects of cannabis on standardised and validated measures of neurocognitive function. Such an approach can be considered an important first step towards developing behavioural measures of impairment.

Characteristics of women concordant and discordant for urine drug screens for cannabis exposure and self-reported cannabis use during pregnancy

BACKGROUND

Increasing cannabis use among pregnant people and equivocal evidence linking prenatal cannabis exposure to adverse outcomes in offspring highlights the need to understand its potential impact on pregnancy and child outcomes. Assessing cannabis use during pregnancy remains a major challenge with potential influences of stigma on self-report as well as detection limitations of easily collected biological matrices.

OBJECTIVE

This descriptive study examined the concordance between self-reported (SR) cannabis use and urine drug screen (UDS) detection of cannabis exposure during the first trimester of pregnancy and characterized concordant and discordant groups for sociodemographic factors, modes of use, secondhand exposure to cannabis and tobacco, and alcohol use and cotinine positivity.

STUDY DESIGN

The Cannabis Use During Development and Early Life (CUDDEL) Study is an ongoing longitudinal study that recruits pregnant individuals presenting for obstetric care, who report lifetime cannabis use as well as using (n = 289) or not using cannabis (n = 169) during pregnancy. During the first trimester pregnancy visit, SR of cannabis use and a UDS for cannabis, other illicit drugs and nicotine are acquired from eligible participants, of whom 333 as of 05/01/2023 had both.

RESULTS

Using available CUDDEL Study data on both SR and UDS (n = 333; age 26.6 ± 4.7; 88.6% Black; 45.4% below federal poverty threshold; 56.5% with paid employment; 89% with high school education; 22% first pregnancy; 12.3 ± 3.6 weeks gestation), we classified pregnant individuals with SR and UDS data into 4 groups based on concordance (k = 0.49 [95% C.I. 0.40-0.58]) between SR cannabis use and UDS cannabis detection during the first trimester: 1) SR+/UDS+ (n = 107); 2) SR-/UDS- (n = 142); 3) SR+/UDS- (n = 44); 4) SR-/UDS+ (n = 40). Those who were SR+/UDS- reported less frequent cannabis use and fewer hours under the influence of cannabis during their pregnancy. Those who were SR-/UDS+ were more likely to have joined the study at a lower gestational age with 62.5% reporting cannabis use during their pregnancy prior to being aware that they were pregnant. Of the 40 SR-/UDS+ women, 14 (i.e., 35%) reported past month secondhand exposure, or blunt usage. In the subset of individuals with SR and UDS available at trimester 2 (N = 160) and 3 (N = 140), concordant groups were mostly stable and > 50% of those in the discordant groups became concordant by the second trimester. Classifying individuals as exposed or not exposed who were SR+ and/or UDS+ resulted in minor changes in group status based on self-report at screening.

CONCLUSION

Overall, there was moderate concordance between SR and UDS for cannabis use/exposure during pregnancy. Instances of SR+/UDS- discordancy may partially be attributable to lower levels of use that are not detected on UDS. SR-/UDS+ discordancy may arise from recent use prior to knowledge of pregnancy, extreme secondhand exposure, deception, and challenges with completing questionnaires. Acquiring both self-report and biological detection of cannabis use/exposure allows for the examination of convergent evidence. Classifying those who are SR+ and/or UDS+ as individuals who used cannabis during their first trimester after being aware of their pregnancy resulted in only a minor change in exposure status; thus, relying on self-report screening, at least in this population and within this sociocultural context likely provides an adequate approximation of cannabis use during pregnancy.

The legalization of cannabis may result in increased indoor exposure to Δ9-tetrahydrocannabinol

Cannabis is a genus of plants in the Cannabaceae family that contains tetrahydrocannabinolic acid. When heated or burned, the acid decarboxylates to form tetrahydrocannabinol (THC). Its (-)-trans-Δ9-THC isomer is a psychoactive substance that has been used as a drug for centuries. In most countries, both the private sale of cannabis products and their use for non-medical purposes are still prohibited by law. However, for some time now there has been societal and political pressure to at least partially legalize cannabis products. It can be expected that such a measure will lead to a significant increase in the consumption of cannabis. However, this also increases the possibility of involuntary passive exposure to THC and contamination of the indoor environment. In indoor sciences, THC is still a largely unknown or underrepresented substance. In this perspective paper, THC will therefore first be presented on the basis of its physical properties. Then, the distribution of THC in different indoor compartments and potential routes of passive exposure are discussed. Finally, an assessment of the future importance of THC for indoor use is made. Previous experience has shown that early monitoring is always advantageous so that preventive and protective measures can be taken quickly if necessary.

Impairment of Endothelial Function by Aerosol From Marijuana Leaf Vaporizers

BACKGROUND

Marijuana leaf vaporizers, which heat plant material and sublimate Δ-9-tetrahydrocannabinol without combustion, are popular alternatives to smoking cannabis that are generally perceived to be less harmful. We have shown that smoke from tobacco and marijuana, as well as aerosol from e-cigarettes and heated tobacco products, impair vascular endothelial function in rats measured as arterial flow-mediated dilation (FMD).

METHODS AND RESULTS

We exposed 8 rats per group to aerosol generated by 2 vaporizer systems (Volcano and handheld Yocan) using marijuana with varying Δ-9-tetrahydrocannabinol levels, in a single pulsatile exposure session of 2 s/min over 5 minutes, and measured changes in FMD. To model secondhand exposure, we exposed rats for 1 minute to diluted aerosol approximating release of uninhaled Volcano aerosol into typical residential rooms. Exposure to aerosol from marijuana with and without cannabinoids impaired FMD by ≈50%. FMD was similarly impaired by aerosols from Yocan (237 °C), and from Volcano at both its standard temperature (185 °C) and the minimum sublimation temperature of Δ-9-tetrahydrocannabinol (157 °C), although the low-temperature aerosol condition did not effectively deliver Δ-9-tetrahydrocannabinol to the circulation. Modeled secondhand exposure based on diluted Volcano aerosol also impaired FMD. FMD was not affected in rats exposed to clean air or water vapor passed through the Volcano system.

CONCLUSIONS

Acute direct exposure and modeled secondhand exposure to marijuana leaf vaporizer aerosol, regardless of cannabinoid concentration or aerosol generation temperature, impair endothelial function in rats comparably to marijuana smoke. Our findings indicate that use of leaf vaporizers is unlikely to reduce the vascular risk burden of smoking marijuana.

Within-subject, double-blind, randomized, placebo-controlled evaluation of combining the cannabinoid dronabinol and the opioid hydromorphone in adults with chronic pain

The potential synergistic effects of combining cannabinoids and opioids for analgesia has received considerable attention. No studies to date have evaluated this combination in patients with chronic pain. The present study aimed to evaluate the combined analgesic and drug effects of oral opioid (hydromorphone) and delta-9-tetrahydrocannabinol (dronabinol), as well as their effects on physical and cognitive functioning, and human abuse potential (HAP) outcomes among individuals with knee osteoarthritis (KOA). This was a within-subject, double-blind, randomized, placebo-controlled study. Participants (N = 37; 65% women; mean age = 62) diagnosed with knee osteoarthritis of ≥3/10 average pain intensity were included. Participants received (1) placebo-placebo, (2) hydromorphone (4 mg)-placebo; (3) dronabinol (10 mg)-placebo, and (4) hydromorphone (4 mg)-dronabinol (10 mg). Clinical and experimentally-induced pain, physical and cognitive function, subjective drug effects, HAP, adverse events, and pharmacokinetics were evaluated. No significant analgesic effects were observed for clinical pain severity or physical functioning across all drug conditions. Little enhancement of hydromorphone analgesia by dronabinol was observed on evoked pain indices. While subjective drug effects and some HAP ratings were increased in the combined drug condition, these were not significantly increased over the dronabinol alone condition. No serious adverse events were reported; hydromorphone produced more mild adverse events than placebo, but hydromorphone + dronabinol produced more moderate adverse events than both placebo and hydromorphone alone. Only hydromorphone impaired cognitive performance. Consistent with laboratory studies on healthy adults, the present study shows minimal benefit of combining dronabinol (10 mg) and hydromorphone (4 mg) for analgesia and improving physical functioning in adults with KOA.

Is Cannabis Effective in the Treatment of Chronic Back Pain?

Cannabis is commonly recognized as a recreational substance. It has been explored for its potential therapeutic applications in addressing various conditions, such as depression, anxiety, sleep disorders, neurological disorders, and chronic low back pain, which affect a significant portion of the population. In the United Kingdom, cannabis has been recognized and licensed for medical use since November 2018, with about 12 National Health Service prescriptions in circulation largely due to patient pressure, with support from media campaigns for its use when there was growing evidence of its use in intractable epilepsy. Cannabis is beginning to gain traction as an alternative or even a complementary drug to opiates with some pre-clinical studies showing opiate-sparing effects. Despite references to its therapeutic use, cannabis as a therapeutic drug has been controversial due to the negative perception of its use as a recreational drug. As a result, there have been challenges in changing the perception of healthcare authorities and clinicians on the use of cannabis as a therapeutic tool for pain relief. The stigma associated with cannabis could be responsible for the paucity of randomized controlled trials on the efficacy of medical cannabis, further decreasing the credibility of the few trials conducted.

Cannabis self-administration in the human laboratory: a scoping review of ad libitum studies

Cannabis self-administration studies may be helpful for identifying factors that influence cannabis consumption and subjective response to cannabis. Additionally, these paradigms could be useful for testing novel pharmacotherapies for cannabis use disorder. This scoping review aims to summarize the findings from existing ad libitum cannabis self-administration studies to determine what has been learned from these studies as well as their limitations. We examined studies that specifically examined cannabis smoking, focusing on subjective response and self-administration behavior (e.g., smoking topography). A systematic search was conducted using PubMed and Embase from inception to October 22, 2022. Our search strategy identified 26 studies (total N = 662, 79% male) that met our eligibility criteria. We found that tetrahydrocannabinol (THC) concentration significantly affected subjective response to cannabis in some but not all studies. In general, cannabis self-administration tended to be most intense at the beginning of the laboratory session and decreased in later parts of the session. There was limited data on cannabis self-administration in adults older than 55. Data on external validity and test-retest reliability were also limited. Addressing these limitations in future ad libitum cannabis self-administration studies could lead to more valid and generalizable paradigms, which in turn could be used to improve our understanding of cannabis use patterns and to help guide medication development for cannabis use disorder.

Measuring PM2.5 concentrations from secondhand tobacco vs. marijuana smoke in 9 rooms of a detached 2-story house

The widespread legalization of recreational marijuana raises growing concerns about exposure to secondhand marijuana smoke. An important location for marijuana smoking is the home, but few measurements of air pollutant concentrations in the home are available for a marijuana joint fully smoked in one of its rooms. We used research grade calibrated real-time continuous PM_2.5 air monitors in controlled 5-hour experiments to measure fine particle concentrations in the 9 rooms of a detached, two-story, 4-bedroom home with either a tobacco cigarette or a marijuana joint fully smoked in the home's living room. The master bedroom's door was closed, and the other bedroom doors were open, as was the custom of occupants of this residence. In two experiments with a Marlboro tobacco cigarette smoked by a machine in the living room, the 5-hour mean PM_2.5 concentrations in 9 rooms of the home were 15.2 μg/m³ (SD 5.6 μg/m³) and 15.0 μg/m³ (SD 3.7 μg/m³). In contrast, three experiments with pre-rolled marijuana joints smoked in the same manner in the living room produced 5-hour mean PM_2.5 concentrations of 38.9 μg/m³ (SD 10.6 μg/m³), 79.8 μg/m³ (SD 25.7 μg/m³) and 80.7 μg/m³ (SD 28.8 μg/m³). In summary, the average secondhand PM_2.5 concentrations from smoking a marijuana joint in the home were found to be 4.4 times as great as the secondhand PM_2.5 concentrations from smoking a tobacco cigarette. Opening 3 windows by 12.7 cm reduced the high PM_2.5 concentrations from marijuana smoking by 67 %, but the PM_2.5 levels still exceeded those produced by tobacco smoking with the windows closed.

Prevalence and factors associated with self-reported exposure to secondhand cannabis smoke in the United States and Canada in 2019

Little is known about exposure to secondhand cannabis smoke (SHCS) among residents of detached single-family homes and multiunit housing (MUH). Using data from the 2019 International Cannabis Policy Study, the prevalence of (a) self-reported exposure to SHCS at home (n = 33,024) and (b) self-reported SHCS incursions into MUH (defined as SHCS from another unit/the outdoors, n = 15,634) was estimated in (1) Canada; (2) US states where non-medical cannabis use was legal, and (3) US states where it remained illegal. Factors associated with exposures and incursions were assessed using weighted logistic regression. Overall, 16.9% of residents in Canada, 20.6% in US legal states, and 15.5% in US illegal states reported exposure to SHCS in their homes at least once in the previous month. One quarter (25.7%) of Canadian MUH residents, 26.6% from US legal states, and 20.1% from US illegal states reported at least monthly incursions. Sociodemographic factors associated with incursions suggested MUH residents reporting incursions lived in qualitatively different MUH than those not reporting incursions. Irrespective of the legality of non-medical cannabis use, smoke-free policies in MUH should protect residents from involuntary exposure to all types of secondhand smoke.

Cannabis industry lobbying in the Colorado state legislature in fiscal years 2010-2021

BACKGROUND

The cannabis industry has an interest in creating a regulatory environment which maximizes profits at the cost of public health, similar to the tobacco, alcohol, and food industries. This study sought to describe the cannabis industry's lobbying activities in the Colorado State Legislature over time.

METHODS

This retrospective observational study analyzed publicly available lobbying expenditures data from fiscal years (FY) 2010-2021. Measures included inflation-adjusted monthly lobbying expenditures by funder and lobbyist, origin of funding, and lobbyist descriptions of cannabis industry clients. This dataset was supplemented with business license documentation, legislative histories, and public testimony.

RESULTS

The cannabis industry spent over $7 million (inflation adjusted) from FY 2010-2021 to lobby the Colorado legislature on 367 bills. Over $800,000 (11% of total cannabis spending) was from out-of-state clients. In 48% of lobbyist reports lobbyists did not disclose their funder's cannabis affiliation, and cannabis organizations used strategies that may have obscured the true amount and source of funding. Lobbyists and agencies concurrently represented the alcohol, tobacco, and cannabis industries, possibly facilitating inter-industry alliances when interests align.

CONCLUSION

The cannabis industry dedicated significant resources towards lobbying the Colorado State Legislature on behalf of policies intended to increase cannabis use. Creating transparency about the relationships between the cannabis industry, related industries, and policymakers is essential to ensure appropriate regulation of cannabis products.

Municipal regulation of cannabis and public health in Canada: A comparison of Alberta, Ontario, and Québec

Canada legalized nonmedical cannabis in October 2018, but significant variations in municipal regulations exist. This study explored the variations that exist and pondered their potential public health consequences. A comparative analysis was completed on the regulations and guidelines that addressed retailers' location and public consumption in the municipalities of Alberta, Ontario, and Québec. Municipal regulations that addressed the location of retailers were more numerous and extensive in Alberta and Ontario (in the context of provincial private retail models) than in Québec (government-based model). Municipalities in Alberta added more restrictions to public consumption laws as compared to municipalities in Ontario and in Québec. These additions were made to Alberta's and Ontario's provincial-level smoking and vaping bans which used tobacco-inspired frameworks, and to Québec's ban on smoking and vaping in all public spaces. The comparative analysis showed the importance of considering municipal cannabis regulations when studying the impact of legalization, given the significant variations that exist. Policy makers should be made aware of these variations in the regulation of cannabis in order to limit health harms and further social inequalities.

Clouding up cognition?: Secondhand cannabis and tobacco exposure related to cognitive functioning in youth

Background

Increasing legalization of cannabis, in addition to longstanding rates of tobacco use, raises concerns for possible cognitive decrements from secondhand smoke or environmental exposure, although little research exists. We investigate the relation between cognition and secondhand and environmental cannabis and tobacco exposure in youth.

Methods

The Adolescent Brain Cognitive Development (ABCD) Study year 2 follow-up (N = 5580; 48% female) cognitive performance and secondhand or environmental cannabis or tobacco exposure data were used. Principal components analysis identified a global cognition factor. Linear mixed-effects models assessed global cognition and individual cognitive task performance by cannabis and/or tobacco environmental exposure. Sociodemographics and other potential confounds were examined. p values were adjusted using the false discovery rate method.

Results

Global cognition was not related to any exposure group after testing corrections and considering confounds. Beyond covariates and family- and site-level factors, secondhand tobacco was related to poorer visual memory (p = .02), and environmental tobacco was associated with poorer visuospatial (p = .02) and language (p = .008) skills. Secondhand cannabis was related to cognition, but not after controlling for potential confounders (p > .05). Environmental cannabis was related to better oral reading (p = .01). Including covariates attenuated effect sizes.

Conclusions

Secondhand tobacco exposure was associated with poorer visual memory, while environmental tobacco exposure was related to poorer language and visuospatial skills. Secondhand cannabis was not related to cognition after controlling for sociodemographic factors, but environmental cannabis exposure was related to better reading. Because, to our knowledge, this is the first known study of its kind and thus preliminary, secondhand cannabis should continue to be investigated to confirm results.

Analytical Approaches and Trends in the Determination of Psychoactive Drugs in Air

Understanding of the levels of psychoactive drugs in air is important for assessing both occupational and environmental exposure. Intelligence on the usage and manufacture of illegal drugs can also be gained. Environmental analysis and determination of air quality has recently expanded from its traditional focus to new pollutant categories that include illicit and psychoactive drugs. This is attributed to a greater part on the development of new, advanced techniques, such as liquid chromatography/mass spectrometry (LC/MS), allowing for the trace determination of such compounds down to the parts-per-trillion (ng/L) levels generally reported in air. Studies have also investigated the effects of firsthand and secondhand smoking of drugs, such as cocaine, cannabis and opium. Generally, these have shown secondhand smoke effects to be limited, apart from in the case of opium. Some studies have highlighted ill effects resulting through the exposure of vapors and dusts from the storage of drugs, but this has been shown to result from mould and other fungal contaminates. Investigations into the possible occupational exposures resulting from the use of anesthetic drugs in surgery and accident and emergency have focused on nitrous oxide, sevoflurane, methoxyflurane, isoflurane, propofol and fentanyl. This review focuses on developments and applications for the determination of psychoactive drugs in air.

Emerging Indoor Air Laws for Onsite Cannabis Consumption Businesses in the U.S

INTRODUCTION

Secondhand cannabis smoke, like secondhand tobacco smoke, creates unhealthy indoor air quality. Ventilation and engineering techniques cannot reduce this pollution to healthy levels, and complete smoke-free policies are the only way to provide healthy indoor environments. Even so, multiple state and local governments have begun to allow indoor smoking of cannabis in businesses.

METHODS

A systematic search of Lexis Advance, NewsBank, and government websites for U.S. state and local laws passed between November 6, 2012 and June 10, 2020 that permit and regulate onsite cannabis consumption businesses was conducted in February-July 2020.

RESULTS

In total, 6 of 11 states and the District of Columbia that legalized adult-use cannabis as of June 10, 2020 allowed onsite consumption and ≥56 localities within these 6 states allowed onsite cannabis consumption. Only 9% (5/56) of localities ban indoor smoking in these businesses; 23% (13/56) require indoor smoking to occur in physically isolated rooms. Other common local legal requirements address onsite odor control, ventilation/filtration, and building location.

CONCLUSIONS

The majority of the localities that allow onsite cannabis consumption do not explicitly prohibit smoking or vaping inside. Policymakers should be made aware that ventilation and other engineering interventions cannot fully protect workers and patrons. Health authorities and local leaders should educate policymakers on the science of secondhand smoke remediation and advocate for the same standards for secondhand cannabis smoking and vaping that apply to tobacco, particularly because other modes of cannabis administration do not pollute the air.

A rapid assay provides on-site quantification of tetrahydrocannabinol in oral fluid

Tetrahydrocannabinol (THC), the primary psychoactive ingredient of cannabis, impairs cognitive and motor function in a concentration-dependent fashion. Drug testing is commonly performed for employment and law enforcement purposes; however, available tests produce low-sensitive binary results (lateral flow assays) or have long turnaround (gas chromatography–mass spectrometry). To enable on-site THC quantification in minutes, we developed a rapid assay for oral THC analysis called EPOCH (express probe for on-site cannabis inhalation). EPOCH features distinctive sensor design such as a radial membrane and transmission optics, all contained in a compact cartridge. This integrated approach permitted assay completion within 5 min with a detection limit of 0.17 ng/ml THC, which is below the regulatory guideline (1 ng/ml). As a proof of concept for field testing, we applied EPOCH to assess oral fluid samples from cannabis users (n = 43) and controls (n = 43). EPOCH detected oral THC in all specimens from cannabis smokers (median concentration, 478 ng/ml) and THC-infused food consumers. Longitudinal monitoring showed a fast drop in THC concentrations within the first 6 hours of cannabis smoking (half-life, 1.4 hours).

Evaluation of nano-confined catalytic oxidation air purification technology on eliminating marijuana chemicals and odour

The novel air purification technology, Nano-Confined Catalytic Oxidation (NCCO), has been proven to be effective at eliminating air pollutants. With the increasing legalization and decriminalization of medicinal and recreational cannabis and related products, respectively, in many countries and jurisdictions around the world, concerns have been raised about indoor air quality from smoking cannabis products, such as marijuana, which produce gaseous pollutants and intense odour. In this study, NCCO technology has been evaluated for its effectiveness in reducing key marijuana concentrations in polluted indoor air by direct measurements and odour intensity assessments by human volunteers. For the odour intensity measurements, 20 non-cannabis adults participated in the odour assessment. The results are remarkable and statistically significant. The reduction in Dronabinol, a pharmaceutical form of Tetrahydrocannabinol (THC), Cannabidiol (CBD) and Cannabinol, averages 93.4%, whereas that in airborne marijuana compounds with no air purification only averages 6.2%. The technology also demonstrates statistically significant reductions in PM2.5, PM10 and total volatile organic compounds generated from marijuana smoke. The technology was able to restore high levels of harmful particulate matter to normal baseline levels. Furthermore, the odour assessment conducted by a group of 20 volunteers also confirmed statistically significant reductions in marijuana odour by 55.6% after 50 min of air purification.

Within-subject, double-blinded, randomized, and placebo-controlled evaluation of the combined effects of the cannabinoid dronabinol and the opioid hydromorphone in a human laboratory pain model

This Phase II study evaluated analgesia, abuse liability, and cognitive performance of hydromorphone and oral delta-9-tetrahydrocannabinol (THC; dronabinol) using a within-subject, double-blind, randomized, placebo-controlled, human laboratory trial. Healthy adults (N = 29) with no history of drug use disorder received combinations of placebo, hydromorphone (4 mg; oral), and dronabinol (2.5 mg, 5.0 mg, 10 mg; oral). Primary outcomes were quantitative sensory testing (QST) measures of acute (thermal, pressure pain; thermal, punctate probe temporal summation; cold pressor; conditioned pain modulation) and chronic pain (capsaicin 10% topical cream with thermal rekindling), measures of drug abuse liability, cognitive functioning, and adverse events. Subgroup analyses were conducted within opioid-responders (endorsed >20 on a Drug Effect visual analog scale during the hydromorphone-only condition) and nonresponders. A consistent dose-effect relationship of dronabinol on hydromorphone across all measures was not observed. Analgesia only improved in the hydromorphone + dronabinol 2.5 mg condition. Hydromorphone + dronabinol 2.5 mg showed the lowest and hydromorphone+dronabinol 5 mg showed the highest risk for abuse. Hydromorphone+dronabinol 10 mg produced a high rate of dysphoric effects, and hydromorphone+dronabinol 5 mg and hydromorphone + dronabinol 10 mg produced AEs. Subgroup analyses showed subjective effects and abuse risk was increased among opioid responders and largely absent among nonresponders. Overall, only hydromorphone+dronabinol 2.5 mg modestly enhanced hydromorphone-based analgesia and hydromorphone + dronabinol 5 mg and 10 mg increased risk for abuse and AEs. These data can help inform opioid-sparing efforts in clinical pain populations. Demonstration that potential opioid effects varied as a function of participant opioid sensitivity (e.g., responder status) is a novel finding that warrants additional research.

Sex differences in the acute effects of oral and vaporized cannabis among healthy adults

Policy changes have increased access to cannabis for individuals with little or no prior exposure. Few studies have examined sex differences in cannabis effects among individuals with sporadic cannabis use or for nonsmoked routes of cannabis administration. Data from four double-blind, placebo-controlled studies were pooled to compare the acute pharmacodynamic effects of vaporized and oral cannabis in male (n = 27) and female (n = 23) participants who used cannabis infrequently (no use ≥30 days prior to randomization). Analyses compared peak change-from-baseline scores between male and female participants for subjective drug effects, cognitive/psychomotor performance, cardiovascular effects, and blood concentrations of Δ9-tetrahydrocannabinol (THC) and its primary metabolites (11-OH-THC, THC-COOH) after exposure to placebo cannabis or cannabis containing low-dose (5 or 10 mg) or high-dose THC (20 or 25 mg). Overall, cannabis elicited dose-orderly increases in subjective effects, impairment of cognitive/psychomotor performance, heart rate, and blood cannabinoid concentrations. Females exhibited greater peak blood 11-OH-THC concentrations and reported greater peak subjective ratings of "drug effect" that remained when controlling for body weight. When controlling for both body weight and peak blood cannabinoid concentrations, ratings of "anxious/nervous," "heart racing," and "restless" were significantly higher for females than males. Although additional research is needed to elucidate sex differences in responses to cannabis at a wider range of THC doses, other routes of administration, and products with diverse chemical composition, the current data indicate that public health messaging and clinical decision making around the use of cannabinoids should recommend lower starting doses for females and warnings about acute anxiogenic reactions.

The effect of cannabidiol on simulated car driving performance: A randomised, double-blind, placebo-controlled, crossover, dose-ranging clinical trial protocol

OBJECTIVE

Interest in the use of cannabidiol (CBD) is increasing worldwide as its therapeutic effects are established and legal restrictions moderated. Unlike Δ9 -tetrahydrocannabinol (Δ9 -THC), CBD does not appear to cause cognitive or psychomotor impairment. However, further assessment of its effects on cognitively demanding day-to-day activities, such as driving, is warranted. Here, we describe a study investigating the effects of CBD on simulated driving and cognitive performance.

METHODS

Thirty healthy individuals will be recruited to participate in this randomised, double-blind, placebo-controlled crossover trial. Participants will complete four research sessions each involving two 30-min simulated driving performance tests completed 45 and 210 min following oral ingestion of placebo or 15, 300, or 1,500 mg CBD. Cognitive function and subjective drug effects will be measured, and blood and oral fluid sampled, at regular intervals. Oral fluid drug testing will be performed using the Securetec DrugWipe® 5S and Dräger DrugTest® 5000 devices to determine whether CBD increases the risk of "false-positive" roadside tests to Δ9 -THC. Noninferiority analyses will test the hypothesis that CBD is no more impairing than placebo.

CONCLUSION

This study will clarify the risks involved in driving following CBD use and assist in ensuring the safe use of CBD by drivers.

Intoxication From Accidental Marijuana Ingestion in Pediatric Patients: What May Lie Ahead

Marijuana is the most commonly used illicit drug. In young children, there are relatively few reports in the literature of acute marijuana intoxication. Here, we describe the case of a previously healthy 2-year-old girl who presented with clinical seizures. A urine toxicology screen showed elevated levels of tetrahydrocannabinol. The source of the drug was not identified. After a short stay in the hospital, the patient fully recovered with only supportive measures. In this report, we also summarize all domestic and international cases of marijuana intoxication in children younger than 6 years, in conjunction with the number of exposures in children of similar age identified by the US National Poison Data System. This report highlights what is becoming a more common problem. As cannabis continues to be decriminalized across the United States with its increasingly diverse modes of delivery, the potential for accidental exposure in infants and young children also rises. Clinicians should now routinely consider marijuana intoxication in children who present with acute neurological abnormalities.

Vaporization of Marijuana Among Recreational Users: A Qualitative Study

OBJECTIVE

Vaporization of marijuana products, or "vaping," has become a prevalent mode of administration and is typically perceived to hold unique benefits compared to combustible administration methods. Such positive beliefs regarding marijuana vaporization may contribute to its abuse liability. This qualitative study examined cognitions pertaining to vaping among recreational marijuana users.

METHOD

Focus groups were conducted with frequent marijuana users (N = 31; five groups; six to seven per group; M = 5.0 days/week marijuana use). Three topic areas were queried during discussions with the goal of revealing factors that may contribute to the abuse liability of vaporization. These comprised differences between smoking and vaporizing marijuana products, perceived advantages of vaporization, and perceived disadvantages of vaporization. Focus groups lasted approximately 60 minutes and followed a semistructured agenda; the sessions were audio recorded and transcribed for an applied thematic analysis. An executive summary of each group was made and key themes pertaining to vaporization were summarized.

RESULTS

Several themes emerged, including differences between smoking and vaporizing marijuana, convenience, discretion, and efficiency of vaping, perceived health benefits, the absence of traditional smoking rituals, and the high cost of vaporization devices.

CONCLUSIONS

Several factors appear to promote marijuana vaporization, including device aspects (e.g., discreet, convenient), the subjective high, economical efficiency, and perceived harm-reducing and health-promoting effects. These qualitative data highlight unique cognitions about marijuana vaping that may substantially increase its abuse liability. Quantitative research is needed to examine the extent to which cognitions about marijuana vaporization contribute to actual use patterns and problematic behaviors.

Occupational Exposure to Secondhand Cannabis Smoke Among Law Enforcement Officers Providing Security at Outdoor Concert Events

Objectives

Numerous states within the USA have legalized cannabis for medical or non-medical (adult/recreational) use. With the increased availability and use of cannabis, occupational and environmental exposures to secondhand cannabis smoke (SHCS) raise concerns over whether non-users may be at risk for a ‘contact high’, impaired neurocognitive function, harm from irritants and carcinogens in smoke, or potentially failing a cannabis screening test. The extent of health effects from potential occupational exposure to SHCS is unknown. This is a study of occupational exposures to SHCS among law enforcement officers (LEOs) providing security at outdoor concerts on a college campus in a state where adult use of cannabis is legal.

Methods

Investigators evaluated a convenience sample of LEOs’ potential exposure to SHCS and symptoms experienced while providing security during two open-air stadium rock-n-roll concerts on consecutive days in July 2018. During each event, full-shift area and LEO personal air samples were collected for Δ9-tetrahydrocannabinol (Δ9-THC), the psychoactive component of cannabis. Urine (pre- and postevent; n = 58) and blood (postevent; n = 29) were also collected and analyzed for Δ9-THC and two of its metabolites [11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and 11-nor-hydroxy-delta-9-tetrahydrocannabinol (OH-THC)]. Urine samples were analyzed using ultrahigh performance liquid chromatography coupled with positive electrospray ionization tandem mass spectrometry and results were compared with the Department of Transportation guidelines for urine screening for cannabis. Blood (postevent) samples were also collected and the plasma fraction was tested for Δ9-THC, THC-COOH, and OH-THC using high-performance liquid chromatography coupled with mass spectrometry. LEOs also completed a medical questionnaire asking about symptoms experienced during the concerts.

Results

Twenty-nine LEOs participated in the evaluation. Measurable amounts of Δ9-THC were found in area (concentrations ranged from non-detectable to 330 ng m−3) and personal air samples (53–480 ng m−3). Small amounts (<1.0 ng ml−1) of a Δ9-THC metabolite (THC-COOH) were found in the postevent urine of 34% of LEOs. Neither Δ9-THC nor its metabolites were detected in any blood sample. LEOs reported experiencing non-specific symptoms during the concerts, such as burning, itchy, or red eyes (31%); dry mouth (21%); headache (21%); and coughing (21%).

Conclusions

Identification of Δ9-THC in the breathing zone for some LEOs indicates the potential for airborne exposure to the psychoactive component of cannabis. However, the magnitude of these exposures was small compared with those that would result in a dose of Δ9-THC associated with psychotropic effects. Similarly, THC-COOH was found in the postevent urine of some LEOs at concentrations that were orders of magnitude below active use cut-points used during a cannabis screening test (50 ng ml−1). Exposure to SHCS was not high enough to detect concentrations of THC, THC-COOH, to OH-THC in the blood, which could be due to differences between the limits of detection for the tests employed. The ocular and respiratory symptoms reported by LEOs may be related to irritants in SHCS. However, the health effects of SHCS remain unclear, and further research concerning occupational and environmental exposures is warranted.

Pharmacodynamic dose effects of oral cannabis ingestion in healthy adults who infrequently use cannabis

BACKGROUND

Prior controlled cannabis research has mostly focused on smoked cannabis and predominantly included frequent cannabis users. Oral cannabis products ("edibles") make up a large and growing segment of the retail cannabis market. This study sought to characterize the pharmacodynamic effects of oral cannabis among infrequent cannabis users.

METHODS

Seventeen healthy adults who had not used cannabis for at least 60 days completed four experimental sessions in which they consumed a cannabis-infused brownie that contained 0, 10, 25, or 50 mg THC. Subjective effects, vital signs, cognitive/psychomotor performance, and blood THC concentrations were assessed before and for 8 h after dosing.

RESULTS

Relative to placebo, the 10 mg THC dose produced discriminable subjective drug effects and elevated heart rate but did not alter cognitive/psychomotor performance. The 25 and 50 mg THC doses elicited pronounced subjective effects and markedly impaired cognitive and psychomotor functioning compared with placebo. For all active doses, pharmacodynamic effects did not manifest until 30-60 min after ingestion, and peak effects occurred 1.5-3 h post-administration. Blood THC levels were significantly correlated with some pharmacodynamic drug effects, but were substantially lower than what is typically observed after cannabis inhalation.

CONCLUSION

Ingestion of oral cannabis dose-dependently altered subjective drug effects and impaired cognitive performance. Unlike inhaled forms of cannabis for which acute effects occur almost immediately, effects of oral cannabis were considerably delayed. In an era of legalization, education about the time course of drug effects for cannabis edibles is needed to facilitate dose titration and reduce acute overdose incidents.

How does cannabidiol (CBD) influence the acute effects of delta-9-tetrahydrocannabinol (THC) in humans? A systematic review

The recent liberalisation of cannabis regulation has increased public and scientific debate about its potential benefits and risks. A key focus has been the extent to which cannabidiol (CBD) might influence the acute effects of delta-9-tetrahydrocannabinol (THC), but this has never been reviewed systematically. In this systematic review of how CBD influences the acute effects of THC we identified 16 studies involving 466 participants. Ten studies were judged at low risk of bias. The findings were mixed, although CBD was found to reduce the effects of THC in several studies. Some studies found that CBD reduced intense experiences of anxiety or psychosis-like effects of THC and blunted some of the impairments on emotion and reward processing. However, CBD did not consistently influence the effects of THC across all studies and outcomes. There was considerable heterogeneity in dose, route of administration and THC:CBD ratio across studies and no clear dose-response profile emerged. Although findings were mixed, this review suggests that CBD may interact with some acute effects of THC.

Prevalence of Involuntary Environmental Cannabis and Tobacco Smoke Exposure in Multi-Unit Housing

No research has examined the prevalence of involuntary cannabis exposure in the home within the context of multi-unit housing (MUH). The 2017 cycle of the Centre for Addiction and Mental Health Monitor population RDD survey included measures of environmental cannabis smoke (ECS) and environmental tobacco smoke (ETS) for Ontario, Canada. These ECS measures were defined for those who did not live in a detached dwelling self-reporting noticing any tobacco or cannabis smoke enter the home from a neighboring unit or from outside the building at least once in the past 6 months. Overall, 6.6% (95% CI: 4.5-9.5%) and 7.5% (9% CI: 5.4-10.4%) of the population reported being exposed to ETS and ECS in MUH respectively. Individuals exposed to ECS were single, had used cannabis in the past 12 months, and had lower household incomes. The prevalence of involuntary exposure to cannabis smoke is similar to exposure to tobacco smoke. Exposure correlates were primarily associated with characteristics of those who lived in MUH who tend to be members of more vulnerable populations.

Detection of Δ9 THC in oral fluid following vaporized cannabis with varied cannabidiol (CBD) content: An evaluation of two point-of-collection testing devices

Point‐of‐collection testing (POCT) for Δ⁹‐tetrahydrocannabinol (THC) in oral fluid is increasingly used to detect driving under the influence of cannabis (DUIC). However, previous studies have questioned the reliability and accuracy of two commonly used POCT devices, the Securetec DrugWipe^® 5 s (DW5s) and Dräger DrugTest^® 5000 (DT5000). In the current placebo controlled, double‐blind, crossover study we used liquid chromatography‐tandem mass spectrometry (LC–MS/MS) to accurately quantify cannabinoid concentrations in the oral fluid of 14 participants at various timepoints (10, 60, 120, and 180 minutes) following vaporization of 125 mg of THC‐dominant (11% THC; <1% CBD), THC/CBD equivalent (11% THC; 11% CBD) and placebo (<1% THC; <1% CBD) cannabis. At each timepoint, oral fluid was also screened using the DW5s (10 ng/mL THC cut‐off) and DT5000 (10 ng/mL THC cut‐off). LC–MS/MS analysis showed peak oral fluid THC concentrations at the 10 minute timepoint with a rapid decline thereafter. This trajectory did not differ with THC dominant and THC/CBD equivalent cannabis. With a 10 ng/mL confirmatory cut‐off, 5% of DW5s test results were false positives and 16% false negatives. For the DT5000, 10% of test results were false positives and 9% false negatives. Neither the DW5s nor the DT5000 demonstrated the recommended >80% sensitivity, specificity and accuracy. Accuracy was lowest at 60 minutes, when THC concentrations were often close to the screening cut‐off (10 ng/mL). POCT devices can be useful tools in detecting recent cannabis use; however, limitations should be noted, and confirmatory LC–MS/MS quantification of results is strongly advisable.

Driving Under the Influence of Cannabis: A Framework for Future Policy

Marijuana is the most widely consumed illicit substance in the United States, and an increasing number of states have legalized it for both medicinal and recreational purposes. As it becomes more readily available, there will be a concurrent rise in the number of users and, consequently, the number of motor vehicle operators driving under the influence. This article examines the cognitive and psychomotor effects of cannabis, as well as current policy concerning driving under the influence of drugs. The authors performed a MEDLINE search on the epidemiology of cannabis use, its cognitive and psychomotor effects, and policies regarding driving under the influence of drugs. Twenty-eight epidemiological studies, 16 acute cognitive and psychomotor studies, 8 chronic cognitive and psychomotor studies, and pertinent state and federal laws and policies were reviewed. These search results revealed that marijuana use is associated with significant cognitive and psychomotor effects. In addition, the legalization of marijuana varies from state to state, as do the laws pertaining to driving under the influence of drugs. Marijuana is a commonly found illicit substance in motor vehicle operators driving under the influence of drugs. Current evidence shows that blood levels of tetrahydrocannabinol do not correlate well with the level of impairment. In addition, although acute infrequent use of cannabis typically leads to cognitive and psychomotor impairment, this is not consistently the case for chronic heavy use. To establish the framework for driving under the influence of cannabis policy, we must review the current published evidence and examine existing policy at state and federal levels.

Indoor cannabis smoke and children's health

Cannabis use is increasing and cannabis is typically consumed by smoking. This study explored how indoor secondhand cannabis smoke (SCS) was associated with child health. As part of a larger trial, air particle monitors were placed in 298 homes of families with at least one cigarette smoker and one child under 14 years old in San Diego County, California. Assessment included past 7-day indoor cigarette and cannabis use, the youngest child's exposure to cigarette smoke, and 5 smoke-related past-year child health outcomes: emergency department use for coughing/difficulty breathing; physician diagnosis of ear infection, bronchitis/bronchiolitis, asthma, or eczema/atopic dermatitis. An ordinal measure of adverse health outcomes (0, 1, or ≥2) was regressed on reported indoor cannabis smoking—the main measure of exposure (yes/no). Of 221 parents/guardians asked about cannabis use, 192 (86.9%) provided all required data, and 29 (15.1%) reported indoor cannabis smoking; reports were supported by air particle data. Homes without indoor smoking had lower average 7-day particle concentrations (1968 particles/0.01ft³) than homes with cannabis smoking only (3131 particles/0.01ft³), cigarette smoking only (3095 particles/0.01ft³), or both cigarette and cannabis smoking (6006 particles/0.01ft³). Odds of reporting a greater number of adverse health outcomes were 1.83 (95% CI = 0.89–3.80, p = 0.10) times higher for children of families with indoor cannabis smoking vs families without cannabis smoking, after controlling for exposure to cigarette smoke and other covariates. Our results do not indicate a statistically significant association. However, the magnitude of the (non-significant) association between indoor cannabis smoking and adverse health outcomes warrants more studies.

•

Indoor cannabis smoking raises particle levels and risk of child particle exposure.

•

Smoking cannabis in-home may adversely impact child health.

•

This adverse impact may occur in homes with or without indoor cigarette smoking.

•

Health effects of secondhand cannabis smoke exposure need to be further explored.

Parental Cannabis Use Is Associated with Cannabis Initiation and Use in Offspring

OBJECTIVES

To assess, before legalization in Canada, whether parental cannabis use is associated with initiation of use in adolescent offspring or with use in young-adult offspring.

STUDY DESIGN

Data were available in 2 longitudinal studies in Montréal, Canada. In AdoQuest, 1048 parents with children in grade 6 reported past-year cannabis use. Cannabis initiation among offspring was measured in grade 7, 9, and/or 11. In the Nicotine Dependence in Teens study, cannabis use data were available for 584 participants (mean age 24 years) and their parents (ie, 542 offspring-mother pairs, 438 offspring-father pairs). The association between parental and offspring cannabis use was estimated using multivariable logistic regression in both studies.

RESULTS

In AdoQuest, grade 6 never-users were 1.8 times more likely to initiate cannabis during high school if their parents reported past-year use. In the Nicotine Dependence in Teens study, the aORs (95% CI) for past-year cannabis use among adult offspring were not different for "mother uses cannabis" (2.8 [1.4-5.8]) or "father uses cannabis" (2.1 [1.2-3.8]). Participants with 1 or 2 cannabis-using parents were 1.7 and 7.1 times more likely to use cannabis, respectively, than participants with non-using parents.

CONCLUSIONS

To enable informed decision-making about their own cannabis use, parents need to be aware that children of cannabis users are more likely to use cannabis in adolescence and young adulthood.

Detection of cannabinoids in hair after cosmetic application of hemp oil

The detection of cannabis constituents and metabolites in hair is an established procedure to provide evidence of exposure to cannabis. We present the first known evidence to suggest that applying hemp oil to hair, as cosmetic treatment, may result in the incorporation of Δ⁹-tetrahydrocannabinol (THC), cannabinol (CBN), cannabidiol (CBD) and in one instance, the metabolite 11-hydroxy-Δ⁹-tetrahydrocannabinol (THC-OH). 10 volunteers treated their head hair daily with commercially available hemp oil for a period of 6 weeks. Head hair samples were collected before and after the application period. Hair samples were washed with methanol and subjected to clean up via liquid/liquid and solid phase extraction procedures, and then GC-MS/MS for the analysis of THC, CBN, CBD, THC-OH and THC-COOH. Application of hemp oil to hair resulted in the incorporation of one or more cannabis constituents in 89% of volunteers, and 33% of the group tested positive for the three major constituents, THC, CBN and CBD. One volunteer showed low levels of the metabolite THC-OH. We suggest that cosmetic use of hemp oil should be recorded when sampling head hair for analysis, and that the interpretative value of cannabinoid hair measurements from people reporting application of hemp oil is treated with caution in both criminology and public health.

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition

BACKGROUND

The main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), can impair driving performance. Cannabidiol (CBD), a non-intoxicating cannabis component, is thought to mitigate certain adverse effects of THC. It is possible then that cannabis containing equivalent CBD and THC will differentially affect driving and cognition relative to THC-dominant cannabis.

AIMS

The present study investigated and compared the effects of THC-dominant and THC/CBD equivalent cannabis on simulated driving and cognitive performance.

METHODS

In a randomized, double-blind, within-subjects crossover design, healthy volunteers (n = 14) with a history of light cannabis use attended three outpatient experimental test sessions in which simulated driving and cognitive performance were assessed at two timepoints (20-60 min and 200-240 min) following vaporization of 125 mg THC-dominant (11% THC; < 1% CBD), THC/CBD equivalent (11% THC, 11% CBD), or placebo (< 1% THC/CBD) cannabis.

RESULTS/OUTCOMES

Both active cannabis types increased lane weaving during a car-following task but had little effect on other driving performance measures. Active cannabis types impaired performance on the Digit Symbol Substitution Task (DSST), Divided Attention Task (DAT) and Paced Auditory Serial Addition Task (PASAT) with impairment on the latter two tasks worse with THC/CBD equivalent cannabis. Subjective drug effects (e.g., "stoned") and confidence in driving ability did not vary with CBD content. Peak plasma THC concentrations were higher following THC/CBD equivalent cannabis relative to THC-dominant cannabis, suggesting a possible pharmacokinetic interaction.

CONCLUSIONS/INTERPRETATION

Cannabis containing equivalent concentrations of CBD and THC appears no less impairing than THC-dominant cannabis, and in some circumstances, CBD may actually exacerbate THC-induced impairment.

Acute Effects of Smoked and Vaporized Cannabis in Healthy Adults Who Infrequently Use Cannabis: A Crossover Trial

IMPORTANCE

Vaporization is an increasingly popular method for cannabis administration, and policy changes have increased adult access to cannabis drastically. Controlled examinations of cannabis vaporization among adults with infrequent current cannabis use patterns (>30 days since last use) are needed.

OBJECTIVE

To evaluate the acute dose effects of smoked and vaporized cannabis using controlled administration methods.

DESIGN, SETTING, AND PARTICIPANTS

This within-participant, double-blind, crossover study was conducted from June 2016 to January 2017 at the Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, and included 17 healthy adults. Six smoked and vaporized outpatient experimental sessions (1-week washout between sessions) were completed in clusters (order counterbalanced across participants); dose order was randomized within each cluster.

INTERVENTIONS

Cannabis containing Δ9-tetrahydrocannabinol (THC) doses of 0 mg, 10 mg, and 25 mg was vaporized and smoked by each participant.

MAIN OUTCOMES AND MEASURES

Change from baseline scores for subjective drug effects, cognitive and psychomotor performance, vital signs, and blood THC concentration.

RESULTS

The sample included 17 healthy adults (mean [SD] age, 27.3 [5.7] years; 9 men and 8 women) with no cannabis use in the prior month (mean [SD] days since last cannabis use, 398 [437] days). Inhalation of cannabis containing 10 mg of THC produced discriminative drug effects (mean [SD] ratings on a 100-point visual analog scale, smoked: 46 [26]; vaporized: 69 [26]) and modest impairment of cognitive functioning. The 25-mg dose produced significant drug effects (mean [SD] ratings, smoked: 66 [29]; vaporized: 78 [24]), increased incidence of adverse effects, and pronounced impairment of cognitive and psychomotor ability (eg, significant decreased task performance compared with placebo in vaporized conditions). Vaporized cannabis resulted in qualitatively stronger drug effects for most pharmacodynamic outcomes and higher peak concentrations of THC in blood, compared with equal doses of smoked cannabis (25-mg dose: smoked, 10.2 ng/mL; vaporized, 14.4 ng/mL). Blood THC concentrations and heart rate peaked within 30 minutes after cannabis administration and returned to baseline within 3 to 4 hours. Several subjective drug effects and observed cognitive and psychomotor impairments persisted for up to 6 hours on average.

CONCLUSIONS AND RELEVANCE

Vaporized and smoked cannabis produced dose-orderly drug effects, which were stronger when vaporized. These data can inform regulatory and clinical decisions surrounding the use of cannabis among adults with little or no prior cannabis exposure.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03676166.

Second-Hand Exposure of Staff Administering Vaporised Cannabinoid Products to Patients in a Hospital Setting

BACKGROUND

In many health settings, administration of medicinal cannabis poses significant implementation barriers including drug storage and safety for administering staff and surrounding patients. Different modes of administration also provide different yet potentially significant issues. One route that has become of clinical interest owing to the rapid onset of action and patient control of the inhaled amount (via breath timing and depth) is that of vaporisation of cannabinoid products. Although requiring a registered therapeutic device for administration, this is a relatively safe method of intrapulmonary administration that may be particularly useful for patients with difficulty swallowing, and for those in whom higher concentrations of cannabinoids are needed quickly. A particular concern expressed to researchers undertaking clinical trials in the hospital is that other patients, nurses, and clinical or research staff may be exposed to second-hand vapours in the course of administering vaporised products to patients.

OBJECTIVE

The objective of this study was to take samples from two research staff involved in administering vaporised Δ⁹-tetrahydrocannabinol to participants in a clinical trial, to examine and quantitate cannabinoid presence.

METHODS

Blood samples from two research staff were taken during the exposure period for three participants (cannabis users) over the course of approximately 2.5 h and analysed using tandem mass spectrometry.

RESULTS

Blood samples taken over a vaporised period revealed exposure below the limit of detection for Δ⁹-tetrahydrocannabinol and two metabolites, using tandem mass spectrometry analytical methods.

CONCLUSIONS

These results are reassuring for hospital and clinical trial practices with staff administering vaporised cannabinoid products, and helpful to ethics committees wishing to quantify risk.

Protecting the public from exposure to secondhand cannabis smoke and vapour following legalization

The adverse effects of direct cannabis use are well described in the literature; however, researchers are now beginning to expose the health consequences of secondhand exposure. Given the commitment by the federal government to legalize cannabis in Canada by summer 2018, public health officials must build on the successes of existing smoke-free programs and work with provinces and municipalities to develop policies that protect the public from secondhand exposure to cannabis smoke and vapour. While harmonization with existing tobacco laws may offer the simplest approach, other alternatives may allow stricter control of public consumption by different levels of government. Further research will be needed to assess the health implications of secondhand cannabis exposure, as well as the population impacts of legalization.

Marijuana Misadventures in Children: Exploration of a Dose-Response Relationship and Summary of Clinical Effects and Outcomes

OBJECTIVES

This study aimed to explore a dose-response relationship of delta-9-tetrahydrocannabinol (THC) in THC-naïve children after unintentional acute exposure and compare clinical outcomes with non-naïve children.

METHODS

A retrospective review was performed on children aged 31 days to 20 years who presented to Children's Hospital Colorado for care related to acute THC toxicity. The children were divided into groups based on exposure: group 1 (THC naïve) and group 2 (THC non-naïve).

RESULTS

A total of 38 children (age, 3.5 [3] years) met inclusion for group 1 and an equal number of children (age, 15.1 [3.9] years) met the criteria for comparison in group 2. Eight naïve patients had documentation of estimated THC dose ingested (mean [SD], 7.13 [5.8] mg/kg; range, 2.9-19.5 mg/kg). A direct relationship between estimated oral THC dose, level of medical intervention required, and hospital disposition was observed. Lethargy/somnolence was more common in the naïve group (84% vs. 26%, P < 0.0001) whereas problems in cognition, perception, and behavior were more common in the non-naïve group (4% vs 11%, P = 0.01). The duration of clinical effect and length of hospital stay were longer in the naïve group (19.3 vs 5.0 hours, P < 0.0001) and (0.73 vs 0.19 days, P < 0.0001) respectively.

CONCLUSIONS

There seems to be a direct relationship between the estimated oral THC dose (mg/kg), hospital disposition, and level of medical intervention required. Symptoms and duration of effects after THC exposure varied based on the route of exposure, age of patient, and history of previous THC experience.

Ethical issues in medical cannabis use

The increasing use of medical cannabis (MC) in the past decade raises several ethical considerations for the clinician. Regulatory issues stem from a gap between MC registration and certification in each country. Professional issues derive from the lack of sufficient knowledge of MC characteristics and the intersection between the physician, the patient and commercial interests. Finally, there are medical and psychological implications which are related to the use of MC regimens. We will discuss these issues in the light of the current era, in which policy has rapidly shifted toward legalization of cannabis, which influences the decisions of both clinicians and patients.

Health effects of exposure to second- and third-hand marijuana smoke: a systematic review

BACKGROUND

Recreational marijuana has been legalized in 11 jurisdictions; Canada will legalize marijuana by July 2018. With this changing landscape, there is a need to understand the public health risks associated with marijuana to support patient-care provider conversations, harm-reduction measures and evidence-informed policy. The objective of this work was to summarize the health effects of exposure to second- and third-hand marijuana smoke.

METHODS

In this systematic review, we searched 6 databases from inception to October 2017. Abstract and full-text review was conducted in duplicate. Studies were included if they were human, in vivo or in vitro studies with more than 1 case reported in English or French, and reported original, quantitative data. Three outcomes were extracted: 1) cannabinoids and cannabinoid metabolites in bodily fluids, 2) self-reported psychoactive effects and 3) eye irritation and discomfort.

RESULTS

Of the 1701 abstracts identified, 60 proceeded to full-text review; the final data set contained 15 articles. All of the included studies were of good to poor quality as assessed with the Downs and Black checklist. There is evidence of a direct relation between the tetrahydrocannabinol content of marijuana and effects on those passively exposed. This relation is mediated by several environmental factors including the amount of smoke, ventilation, air volume, number of marijuana cigarettes lit and number of smokers present. No evidence was identified assessing exposure to third-hand marijuana smoke or the health effects of long-term exposure.

INTERPRETATION

Exposure to second-hand marijuana smoke leads to cannabinoid metabolites in bodily fluids, and people experience psychoactive effects after such exposure. Alignment of tobacco and marijuana smoking bylaws may result in the most effective public policies. More research is required to understand the impact of exposure to third-hand smoke and the health effects of long-term exposure to second-hand smoke.

Pharmacokinetic Profile of Oral Cannabis in Humans: Blood and Oral Fluid Disposition and Relation to Pharmacodynamic Outcomes

Most research on cannabis pharmacokinetics has evaluated inhaled cannabis, but oral ("edible") preparations comprise an increasing segment of the cannabis market. To assess oral cannabis pharmacokinetics and pharmacodynamics, healthy adults (N = 6 per dose) were administered cannabis brownies containing 10, 25 or 50 mg 9-tetrahydrocannabinol (THC). Whole blood and oral fluid specimens were obtained at baseline and then for 9 days post-exposure; 6 days in a residential research setting and 3 days as outpatients. Measures of subjective, cardiovascular and performance effects were obtained at baseline and for 8 h post-ingestion. The mean Cmax for THC in whole blood was 1, 3.5 and 3.3 ng/mL for the 10, 25 and 50 mg THC doses, respectively. The mean maximum concentration (Cmax) and mean time to maximum concentration (Tmax) of 11-OH-THC in whole blood were similar to THC. Cmax blood concentrations of THCCOOH were generally higher than THC and had longer Tmax values. The mean Tmax for THC in oral fluid occurred immediately following oral dose administration, and appear to reflect local topical residue rather than systemic bioavailbility. Mean Cmax oral fluid concentrations of THCCOOH were lower than THC, erratic over time and mean Tmax occurred at longer times than THC. The window of THC detection ranged from 0 to 22 h for whole blood (limit of quantitation (LOQ) = 0.5 ng/mL) and 1.9 to 22 h for oral fluid (LOQ = 1.0 ng/mL). Subjective drug and cognitive performance effects were generally dose dependent, peaked at 1.5-3 h post-administration, and lasted 6-8 h. Whole blood cannabinoid concentrations were significantly correlated with subjective drug effects. Correlations between blood cannabinoids and cognitive performance measures, and between oral fluid and all pharmacodynamic outcomes were either non-significant or not orderly by dose. Quantitative levels of cannabinoids in whole blood and oral fluid were low compared with levels observed following inhalation of cannabis. The route of administration is important for interpretation of cannabinoid toxicology.

Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens

Urine drug testing is frequently used in clinical, employment, educational, and legal settings and misinterpretation of test results can result in significant adverse consequences for the individual who is being tested. Advances in drug testing technology combined with a rise in the number of novel misused substances present challenges to clinicians to appropriately interpret urine drug test results. Authors searched PubMed and Google Scholar to identify published literature written in English between 1946 and 2016, using urine drug test, screen, false-positive, false-negative, abuse, and individual drugs of abuse as key words. Cited references were also used to identify the relevant literature. In this report, we review technical information related to detection methods of urine drug tests that are commonly used and provide an overview of false-positive/false-negative data for commonly misused substances in the following categories: cannabinoids, central nervous system (CNS) depressants, CNS stimulants, hallucinogens, designer drugs, and herbal drugs of abuse. We also present brief discussions of alcohol and tricyclic antidepressants as related to urine drug tests, for completeness. The goal of this review was to provide a useful tool for clinicians when interpreting urine drug test results and making appropriate clinical decisions on the basis of the information presented.

Traversing the triangulum: the intersection of tobacco, legalised marijuana and electronic vaporisers in Denver, Colorado

OBJECTIVE

To explore the intersection of tobacco, legalised marijuana and electronic vaporiser use among young adults in the 'natural laboratory' of Colorado, the first state with legalised retail marijuana.

METHODS

We conducted semistructured interviews with 32 young adults (18-26 years old) in Denver, Colorado, in 2015 to understand the beliefs and practices related to the use of tobacco, marijuana and vaporisers.

RESULTS

We found ambiguity about whether the phrase 'to smoke' refers to the use of tobacco or marijuana products. Smoking marijuana blunts (emptied cigarillo or tobacco wrap filled with marijuana) was common, but few interpreted this as tobacco use. Marijuana vaporisers were used to circumvent public consumption laws (eg, while at work or when driving). Young adults considered secondhand tobacco smoke dangerous, but perceived secondhand marijuana smoke as benign.

DISCUSSION

Using tobacco products as a delivery method for marijuana (eg, blunts) might be increasing and normalising tobacco use among young adults. Surveillance should explicitly ask about use of tobacco products for marijuana. Marijuana vaporisers, often indistinguishable from nicotine vaporisers, may be used to circumvent public consumption laws; communities concerned about use of marijuana in public spaces should include vaporisers (for nicotine or marijuana) in smoke-free regulations. Tobacco, marijuana and electronic vaporisers should be studied together, rather than separately. This approach is essential in informing research and policy as more US states and countries worldwide move to legalise marijuana.

An Exploratory Human Laboratory Experiment Evaluating Vaporized Cannabis in the Treatment of Neuropathic Pain From Spinal Cord Injury and Disease

Using 8-hour human laboratory experiments, we evaluated the analgesic efficacy of vaporized cannabis in patients with neuropathic pain related to injury or disease of the spinal cord, most of whom were experiencing pain despite traditional treatment. After obtaining baseline data, 42 participants underwent a standardized procedure for inhaling 4 puffs of vaporized cannabis containing either placebo, 2.9%, or 6.7% delta 9-THC on 3 separate occasions. A second dosing occurred 3 hours later; participants chose to inhale 4 to 8 puffs. This flexible dosing was used to attempt to reduce the placebo effect. Using an 11-point numerical pain intensity rating scale as the primary outcome, a mixed effects linear regression model showed a significant analgesic response for vaporized cannabis. When subjective and psychoactive side effects (eg, good drug effect, feeling high, etc) were added as covariates to the model, the reduction in pain intensity remained significant above and beyond any effect of these measures (all P < .0004). Psychoactive and subjective effects were dose-dependent. Measurement of neuropsychological performance proved challenging because of various disabilities in the population studied. Because the 2 active doses did not significantly differ from each other in terms of analgesic potency, the lower dose appears to offer the best risk-benefit ratio in patients with neuropathic pain associated with injury or disease of the spinal cord.

PERSPECTIVE

A crossover, randomized, placebo-controlled human laboratory experiment involving administration of vaporized cannabis was performed in patients with neuropathic pain related to spinal cord injury and disease. This study supports consideration of future research that would include longer duration studies over weeks to months to evaluate the efficacy of medicinal cannabis in patients with central neuropathic pain.

One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function

BACKGROUND

Despite public awareness that tobacco secondhand smoke (SHS) is harmful, many people still assume that marijuana SHS is benign. Debates about whether smoke-free laws should include marijuana are becoming increasingly widespread as marijuana is legalized and the cannabis industry grows. Lack of evidence for marijuana SHS causing acute cardiovascular harm is frequently mistaken for evidence that it is harmless, despite chemical and physical similarity between marijuana and tobacco smoke. We investigated whether brief exposure to marijuana SHS causes acute vascular endothelial dysfunction.

METHODS AND RESULTS

We measured endothelial function as femoral artery flow-mediated dilation (FMD) in rats before and after exposure to marijuana SHS at levels similar to real-world tobacco SHS conditions. One minute of exposure to marijuana SHS impaired FMD to a comparable extent as impairment from equal concentrations of tobacco SHS, but recovery was considerably slower for marijuana. Exposure to marijuana SHS directly caused cannabinoid-independent vasodilation that subsided within 25 minutes, whereas FMD remained impaired for at least 90 minutes. Impairment occurred even when marijuana lacked cannabinoids and rolling paper was omitted. Endothelium-independent vasodilation by nitroglycerin administration was not impaired. FMD was not impaired by exposure to chamber air.

CONCLUSIONS

One minute of exposure to marijuana SHS substantially impairs endothelial function in rats for at least 90 minutes, considerably longer than comparable impairment by tobacco SHS. Impairment of FMD does not require cannabinoids, nicotine, or rolling paper smoke. Our findings in rats suggest that SHS can exert similar adverse cardiovascular effects regardless of whether it is from tobacco or marijuana.

Vaping cannabis (marijuana): parallel concerns to e-cigs?

The proliferation of vaporization ('vaping') as a method for administering cannabis raises many of the same public health issues being debated and investigated in relation to e-cigarettes (e-cigs). Good epidemiological data on the prevalence of vaping cannabis are not yet available, but with current trends towards societal approval of medicinal and recreational use of cannabis, the pros and cons of vaping cannabis warrant study. As with e-cigs, vaping cannabis portends putative health benefits by reducing harm from ingesting toxic smoke. Indeed, vaping is perceived and being sold as a safer way to use cannabis, despite the lack of data on the health effects of chronic vaping. Other perceived benefits include better taste, more efficient and intense effects and greater discretion which allows for use in more places. Unfortunately, these aspects of vaping could prompt an increased likelihood of trying cannabis, earlier age of onset, more positive initial experiences, and more frequent use, thereby increasing the probability of problematic use or addiction. Sales and marketing of vaping devices with no regulatory guidelines, especially related to advertising or product development targeting youth, parallels concerns under debate related to e-cigs and youth. Thus, the quandary of whether or not to promote vaping as a safer method of cannabis administration for those wishing to use cannabis, and how to regulate vaping and vaping devices, necessitates substantial investigation and discussion. Addressing these issues in concert with efforts directed towards e-cigs may save time and energy and result in a more comprehensive and effective public health policy on vaping.

Nonsmoker Exposure to Secondhand Cannabis Smoke. III. Oral Fluid and Blood Drug Concentrations and Corresponding Subjective Effects

The increasing use of highly potent strains of cannabis prompted this new evaluation of human toxicology and subjective effects following passive exposure to cannabis smoke. The study was designed to produce extreme cannabis smoke exposure conditions tolerable to drug-free nonsmokers. Six experienced cannabis users smoked cannabis cigarettes [5.3% Δ(9)-tetrahydrocannabinol (THC) in Session 1 and 11.3% THC in Sessions 2 and 3] in a closed chamber. Six nonsmokers were seated alternately with smokers during exposure sessions of 1 h duration. Sessions 1 and 2 were conducted with no ventilation and ventilation was employed in Session 3. Oral fluid, whole blood and subjective effect measures were obtained before and at multiple time points after each session. Oral fluid was analyzed by ELISA (4 ng/mL cutoff concentration) and by LC-MS-MS (limit of quantitation) for THC (1 ng/mL) and total THCCOOH (0.02 ng/mL). Blood was analyzed by LC-MS-MS (0.5 ng/mL) for THC, 11-OH-THC and free THCCOOH. Positive tests for THC in oral fluid and blood were obtained for nonsmokers up to 3 h following exposure. Ratings of subjective effects correlated with the degree of exposure. Subjective effect measures and amounts of THC absorbed by nonsmokers (relative to smokers) indicated that extreme secondhand cannabis smoke exposure mimicked, though to a lesser extent, active cannabis smoking.