The Potential for Pharmacokinetic Interactions Between Cannabis Products and Conventional Medications

Tetrahydrocannabinol and Its Major Metabolites Are Not (or Are Poor) Substrates or Inhibitors of Human P-Glycoprotein [ATP-Binding Cassette (ABC) B1] and Breast Cancer Resistance Protein (ABCG2)

(-)-Δ9-Tetrahydrocannabinol (THC) is the primary psychoactive constituent of cannabis. In humans, 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THC-COOH) are psychoactive and nonpsychoactive circulating metabolites of THC, respectively. Whether these cannabinoids are substrates or inhibitors of human P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP) is unknown. Previous animal studies suggest that THC and its metabolites could be substrates of these transporters. Therefore, we performed Transwell, cellular accumulation, and vesicular transport assays, at pharmacologically relevant concentrations of these cannabinoids, using Madin-Darby canine kidney (MDCK) II cells or plasma membrane vesicles overexpressing human P-gp or BCRP. Neither THC nor 11-OH-THC was found to be a substrate or inhibitor of P-gp or BCRP. The efflux ratio of THC-COOH in MDCKII-BCRP cells was 1.6, which was significantly decreased to 1.0 by the BCRP inhibitor Ko143. Likewise, cellular accumulation of THC-COOH was significantly increased 1.6-fold in the presence versus absence of Ko143. THC-COOH also significantly inhibited BCRP-mediated transport of Lucifer yellow, a BCRP substrate; however, THC-COOH was neither a substrate nor an inhibitor of P-gp. Collectively, these results indicate that THC and 11-OH-THC are not substrates or inhibitors (at pharmacologically relevant concentrations) of either P-gp or BCRP. THC-COOH is a weak substrate and inhibitor of BCRP, but not of P-gp. Accordingly, we predict that P-gp/BCRP will not modulate the disposition of these cannabinoids in humans. In addition, use of these cannabinoids will not result in P-gp- or BCRP-based drug interactions. SIGNIFICANCE STATEMENT: This study systematically investigated whether Δ9-tetrahydrocannabinol (THC) and its major metabolites, 11-hydroxy-THC and 11-nor-9-carboxy-THC, are substrates and/or inhibitors of human P-gp and BCRP at pharmacologically relevant concentrations. The results obtained are highly valuable for mechanistic understanding and prediction of the roles of P-gp and BCRP in determining the human pharmacokinetics, tissue distribution, and drug interactions of cannabinoids.

Interaction of Energy Drinks with Prescription Medication and Drugs of Abuse

In recent years, the consumption of energy drinks (EDs) has become increasingly popular, especially among adolescents. Caffeine, a psychostimulant, is the main compound of EDs which also contain other substances with pharmacological effects. This review aims to compile current evidence concerning the potential interactions between EDs, medicines, and drugs of abuse as they are frequently consumed in combination. The substances involved are mainly substrates, inductors or inhibitors of CYP1A2, psychostimulants, alcohol and other depressant drugs. Furthermore, intoxications reported with EDs and other substances have also been screened to describe acute toxicity. The results of our review show that the consumption of both EDs alone and in combination is not as safe as previously thought. Health professionals and consumers need to be aware of the potential interactions of these drinks as well as the absence of long-term safety data.

A Case Series of Etizolam in Opioid-Related Deaths

Etizolam is a novel psychoactive substance and novel benzodiazepine of the thienotriazolodiazepine class, which has recently seen an increasing trend in use worldwide. We report a case series of 10 decedents with etizolam and opioids in their systems. Death investigation, expanded toxicology and medical investigation information were included for contextualization of etizolam in death. Etizolam was detected and confirmed within peripheral and cardiac blood, urine, vitreous humor and, in one case, gastric fluid, by liquid chromatography-tandem mass spectrometry and liquid chromatography-quadrupole time of flight mass spectrometry methodologies. Death investigation indicated nonmedical use of most drugs. Medical investigation commonly noted pulmonary edema, cardiomegaly and cerebral swelling. The majority of the decedents appeared to be unaware of the presence of etizolam and succumbed to the mixed drug toxicity of their routine depressant and narcotic analgesic drug of abuse in combination with etizolam. Etizolam use continues to be observed and poses as a potentially lethal contribution to multiple drug toxicity, especially in the age of the opioid crisis. Assessment of analytes like etizolam requires up-to-date methodologies and vigilance in testing to better characterize the toxicology and interpret the contribution to death.

Natural and Synthetic Cannabinoids: Pharmacology, Uses, Adverse Drug Events, and Drug Interactions

The purpose of this narrative review is to describe the current use environment of both natural and synthetic cannabinoids while providing context for cannabinoid chemistry and pharmacology. In addition to a long history of recreational and nonmedical use, natural cannabinoids are increasingly used as prescription products, through medical cannabis programs, and as consumer health products. Despite anecdotal safety evidence, cannabis and cannabinoids are pharmacologically complex and pose risks for adverse drug events and drug-drug interactions. Synthetic cannabinoids, particularly agonists of cannabinoid receptors, are more potent than natural cannabinoids and can lead to more severe reactions and medical emergencies. This review provides a summary of approved uses and an overview of mechanisms of action for adverse drug events with natural and synthetic cannabinoids. Clinical considerations for special populations that may be at heightened risk for drug-drug interactions and adverse drug events while using natural or synthetic cannabinoids are examined, and recommendations are provided.

Chlorpyrifos and Δ9 Tetrahydrocannabinol exposure and effects on parameters associated with the endocannabinoid system and risk factors for obesity

Marilyn Silva. Retired from a career in toxicology and risk assessment. Increased childhood and adult obesity are associated with chlorpyrifos (CPF), an organophosphate pesticide. Cannabis (Δ9Tetrahydrocannabinol: Δ9THC) use has increased globally with legalization. CPF applications on cannabis crops lacks federally regulated tolerances and may pose health risks through exposure during development and in adulthood. Both CPF and Δ9THC affect the endocannabinoid system (eCBS), a regulator of appetite, energy balance, and gut microbiota, which, if disrupted, increases risk for obesity and related diseases. CPF inhibits eCB metabolism and Δ9THC is a partial agonist/antagonist at the cannabinoid receptor (CB1R). Effects of each on obesogenic parameters were examined via literature search. Male rodents with CPF exposure showed increased body weights, dysbiosis, inflammation and oxidative stress, potentially associated with increased eCBs acting through the gut-microbiota-adipose-brain regulatory loop. Δ9THC generally decreased body weights via partial agonism at the CB1R, lowering levels of eCBs. Dysbiosis and/or oxidative stress associated inflammation occurred with CPF, but these parameters were not tested with Δ9THC. Database deficiencies included limited endpoints to compare between chemicals/age-groups, inter-study variables (dose ranges, dosing vehicle, rodent strain, treatment duration, etc.). CPF and Δ9THC were not tested together, but human co-chemical effects would depend on exposure ratio, subject age, exposure duration, and health status, among others. An overriding concern is that both chemicals are well-documented developmental neurotoxins in addition to their low dose effects on energy balance. A co-exposure risk assessment is warranted with increased use and lack of federal CPF regulation on cannabis.

Practical considerations for testing the effects of cannabidiol on human anxiety

Empirical evidence continues to accumulate suggesting cannabidiol (CBD) may have potential as an anxiolytic. Yet, research in the area is insufficient to support strong inferences. Accordingly, there is a need for additional empirical investigation. Research on the effects of CBD and anxiety requires a working knowledge of both. Understanding of contemporary CBD and anxiety research methods is critical to safely and convincingly test predictions regarding potential anxiolytic effects of CBD. The current paper outlines major design, methods, and safety considerations pertinent both to CBD administration and measuring effects on anxiety outcomes in order to facilitate needed research in this domain.

Exploring the use of cannabis as a substitute for prescription drugs in a convenience sample

BACKGROUND

The use of cannabis as medicine (CaM) both prescribed and non-prescribed has increased markedly in the last decade, mirrored in a global shift in cannabis policy towards a more permissive stance. There is some evidence that cannabis functions as a substitute for prescription drugs, particularly opioids; however, more knowledge is needed on the motives of substitution users, their patterns of use, and perceived effects of substitution use.

AIMS

To explore who substitutes prescription drugs with cannabis, the type of prescription drugs substituted and the type of cannabis used, and the impact that substitution with cannabis has on prescription drug use as well as the motives for substitution in terms of experienced effects and side effects.

METHODS

A self-selected convenience sample was recruited through social media, public media, and patient organizations to take part in an anonymous online survey. Inclusion criteria were 18 years or older and use of cannabis (prescribed or non-prescribed) with a medical purpose.

RESULTS

The final sample included 2.841 respondents of which the majority (91%) used non-prescribed cannabis, and more than half (54.6%) had used CaM with the purpose of replacing a prescribed drug. Compared to non-substitution users, substitution users were more likely to be women and to use CaM in the treatment of chronic pain and other somatic conditions. Pain medication (67.2%), antidepressants (24.5%), and arthritis medication (20.7%) were the most common types of drugs replaced with CaM. Among substitution users, 38.1% reported termination of prescription drug use, and 45.9% a substantial decrease in prescription drug use. The most frequent type of cannabis used as a substitute was CBD-oil (65.2%), followed by 'hash, pot or skunk' (36.6%). More than half (65.8%) found CaM much more effective compared to prescription drugs, and 85.5% that the side effects associated with prescription drug use were much worse compared to use of CaM.

CONCLUSION

CaM is frequently used as a substitute for prescription drugs, particularly opioids. More research is needed on the long-term consequences of use of CaM, including the impact from low and high THC cannabis products on specific somatic and mental health conditions.

The Impact of Marijuana on Antidepressant Treatment in Adolescents: Clinical and Pharmacologic Considerations

The neuropharmacology of marijuana, including its effects on selective serotonin reuptake inhibitor (SSRI)/antidepressant metabolism and the subsequent response and tolerability in youth, has received limited attention. We sought to (1) review clinically relevant pharmacokinetic (PK) and pharmacodynamic (PD) interactions between cannabinoids and selected SSRIs, (2) use PK models to examine the impact of cannabinoids on SSRI exposure (area under curve (AUC)) and maximum concentration (C_MAX) in adolescents, and (3) examine the frequency of adverse events reported when SSRIs and cannabinoids are used concomitantly. Cannabinoid metabolism, interactions with SSRIs, impact on relevant PK/PD pathways and known drug–drug interactions were reviewed. Then, the impact of tetrahydrocannabinol (THC) and cannabidiol (CBD) on exposure (AUC₂₄) and C_MAX for escitalopram and sertraline was modeled using pediatric PK data. Using data from the Food and Drug Administration Adverse Events Reporting System (FAERS), the relationship between CBD and CYP2C19-metabolized SSRIs and side effects was examined. Cannabis and CBD inhibit cytochrome activity, alter serotonergic transmission, and modulate SSRI response. In PK models, CBD and/or THC increases sertraline and es/citalopram concentrations in adolescents, and coadministration of CBD and CYP2C19-metabolized SSRIs increases the risk of cough, diarrhea, dizziness, and fatigue. Given the significant SSRI–cannabinoid interactions, clinicians should discuss THC and CBD use in youth prescribed SSRIs and be aware of the impact of initiating, stopping, or decreasing cannabinoid use as this may significantly affect es/citalopram and sertraline exposure.

"Light cannabis" consumption in a sample of young adults: Preliminary pharmacokinetic data and psychomotor impairment evaluation

INTRODUCTION

In 2019, the Italian Supreme Court established that hemp cannot be commercialized for human use, when the "psychotropic effect" of the product or its "offensiveness" can be demonstrated. The aim of the present study is to assess Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) blood concentrations after smoking cannabis with a low percentage of Δ9-THC, also referred as "light cannabis", and its effects on young adults' vigilance, cognitive and motor skills.

MATERIALS AND METHODS

Eighteen young adults consumed three light cannabis cigarettes containing 400 mg of inflorescences each, with a percentage of 0.41% of Δ9-THC and of 12.41% of CBD. Blood samples were collected before the experiment (t0), after each light cannabis cigarette (t1→t3), 60 (t4) and 120 (t5) minutes after the beginning of the experiment. Five performance tasks and a subjective scale were employed for measuring cognitive and psychomotor performances the day before the experiment (TT0) and after the third cigarette (TT1).

RESULTS

Mean (SD) concentrations (ng/ml) were 1.0 (0.8) in t1, 1.2 (0.9) in t2, 1.0 (0.8) in t3, 0.6 (0.4) in t4 and 0.3 (0.3) in t5 for Δ9-THC; 10.5 (10.3) in t1, 10.3 (13.2) in t2, 15.1 (14.8) in t3, 9.9 (9.2) in t4 and 5.7 (5.7) in t5 for CBD. No significant differences were observed between TT0 and TT1 for all performed psychomotor performance task. None of the subjects declared to feel "high" after the experiment.

DISCUSSION

All study participants reported that a higher number of cigarettes, corresponding in this study to 1200 mg of herbal product, could hardly be consumed by smoking in a recreational setting. Δ9-THC and CBD concentrations showed a high inter-subject variability, and the average concentrations were lower than those previously reported. Toxicological results showed a decrease of Δ9-THC and CBD after the third light cannabis cigarette, and a Δ9-THC /CBD ratio always<1 was observed. The lack of impairment observed in our participants can be interpreted as a consequence of the very low concentrations detectable in the blood.

Cannabis Use in Older Adults: A Perspective

The prevalence of cannabis use among older adults (aged 65 and above) for both recreational and medicinal purposes has significantly increased in recent years. Information regarding the safety of cannabis in this population is important since aging is associated with metabolic changes, multiple morbidities, increases in prescription medication use, and an overall decline in functioning. In this Perspectives article, we review special considerations pertinent to older adults-specifically, the impact of cannabis on cognition and on falls and injuries, its drug interactions, and its potential medicinal applications for treating the behavioral and psychological symptoms of dementia. Knowledge about the role of cannabis in brain health, injury risk, and drug interactions remains limited since the available evidence stems primarily from adolescent and young adult cohorts, plus a limited number of small observational studies with older adults. In terms of utilizing certain cannabinoids to treat the behavioral and psychological symptoms of dementia, some studies have found promising results, but because of the lack of consistency in the literature, it is premature to draw conclusions. Controlled research trials specifically with geriatric participants are needed to understand the effects of cannabis use in this vulnerable population.

Assessment of antiviral potencies of cannabinoids against SARS-CoV-2 using computational and in vitro approaches

Effective treatment choices to the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are limited because of the absence of effective target-based therapeutics. The main object of the current research was to estimate the antiviral activity of cannabinoids (CBDs) against the human coronavirus SARS-CoV-2. In the presented research work, we performed in silico and in vitro experiments to aid the sighting of lead CBDs for treating the viral infections of SARS-CoV-2. Virtual screening was carried out for interactions between 32 CBDs and the SARS-CoV-2 Mpro enzyme. Afterward, in vitro antiviral activity was carried out of five CBDs molecules against SARS-CoV-2. Interestingly, among them, two CBDs molecules namely Δ9 -tetrahydrocannabinol (IC50 = 10.25 μM) and cannabidiol (IC50 = 7.91 μM) were observed to be more potent antiviral molecules against SARS-CoV-2 compared to the reference drugs lopinavir, chloroquine, and remdesivir (IC50 ranges of 8.16-13.15 μM). These molecules were found to have stable conformations with the active binding pocket of the SARS-CoV-2 Mpro by molecular dynamic simulation and density functional theory. Our findings suggest cannabidiol and Δ9 -tetrahydrocannabinol are possible drugs against human coronavirus that might be used in combination or with other drug molecules to treat COVID-19 patients.

Clinical Conditions and Prescription Drug Utilization among Early Medical Marijuana Registrants in Florida

Initial legalization of medical marijuana (MM) in Florida required providers to submit initial and follow-up treatment plan forms to the University of Florida to support research on MM safety and efficacy. This study retrospectively analyzed all treatment plan forms submitted between program inception (August 2016) through July 2017 and describes early Florida MM registrants by clinical conditions and prescription drug utilization. Among 7,548 unique treatment plans, the initial visit was characterized by registrants who were mostly white (83.7%), 52.3 (SD 16.4) years of age on average, and who were assessed by the provider as at least moderately ill (79.6%). Musculoskeletal and spasticity-related conditions (44.8%), chronic pain (41.9%), and mental health disorders (17.0%) were the most frequent medical complaints for seeking MM treatment with more than one condition per patient possible. One in four (25.9%) patients reported use of prescription opioids and over one-fifth of patients frequently utilized at least one psychotropic medication as well as cardiovascular agents. There were 2,075 unique follow-up plans available which were mostly characterized by clinical improvement and reported reductions in utilization of some drug classes. Further research is needed to guide clinicians on the risks and benefits of MM used concomitantly with prescription drugs.

Gender Differences in Medical Cannabis Use: Symptoms Treated, Physician Support for Use, and Prescription Medication Discontinuation

Background: Medical cannabis (MC) utilization continues to expand in the United States, as a growing body of evidence supports the use of cannabis and cannabinoids in the treatment of a range of chronic conditions. To date, gender-related differences in MC use are not widely reported, and little is known regarding physicians' support of patients' use of MC to address symptoms associated with chronic conditions. Materials and Methods: We conducted a cross-sectional online survey of MC users in Illinois (n = 361). We summarized participants' qualifying conditions, symptoms treated with MC, perceived physician support for MC use, use of MC and prescription medications, then analyzed differences by participant gender. Results: Bivariate analyses indicate that men report higher levels of support for MC use from both specialist and primary care physicians. Women were significantly more likely to increase use of cannabis after acquiring an MC card, and to discontinue prescription medications through MC use. Multivariable analyses indicate that being a woman, using MC to treat multiple symptoms, and reporting higher levels of support for MC use from a primary care provider significantly increased the likelihood of discontinuing prescription medication through MC use. Discussion: Women are more likely to report decreased use of prescription medications to treat symptoms, and report lower levels of support from physicians for MC use. Future research on gender differences in this population may benefit from more detailed data related to symptomology, utilization, dosing, and outcomes associated with MC, and interactions with the health care system to extend these findings.

Safety and Molecular-Toxicological Implications of Cannabidiol-Rich Cannabis Extract and Methylsulfonylmethane Co-Administration

Cannabidiol (CBD) is a biologically active, non-psychotropic component of Cannabis sativa whose popularity has grown exponentially in recent years. Besides a wealth of potential health benefits, ingestion of CBD poses risks for a number of side effects, of which hepatotoxicity and CBD/herb-drug interactions are of particular concern. Here, we investigated the interaction potential between the cannabidiol-rich cannabis extract (CRCE) and methylsulfonylmethane (MSM), a popular dietary supplement, in the mouse model. For this purpose, 8-week-old male C57BL6/J mice received MSM-containing water (80 mg/100 mL) ad libitum for 17 days. During the last three days of treatment, mice received three doses of CRCE administered in sesame oil via oral gavage (123 mg/kg/day). Administration of MSM alone did not result in any evidence of liver toxicity and did not induce expression of mouse cytochrome P450 (CYP) enzymes. Administration of CRCE did produce significant (p < 0.05) increases in Cyp1a2, Cyp2b10, Cyp2c29, Cyp3a4, Cyp3a11, Cyp2c65, and Cyp2c66 messenger RNA, however, this effect was not amplified by MSM/CRCE co-treatment. Similarly, no evidence of liver toxicity was observed in MSM/CRCE dosed mice. In conclusion, short-term MSM/CRCE co-administration did not demonstrate any evidence of hepatotoxicity in the mouse model.

Cannabis: An Emerging Treatment for Common Symptoms in Older Adults

BACKGROUND/OBJECTIVES

Use of cannabis is increasing in a variety of populations in the United States; however, few investigations about how and for what reasons cannabis is used in older populations exist.

DESIGN

Anonymous survey.

SETTING

Geriatrics clinic.

PARTICIPANTS

A total of 568 adults 65 years and older.

INTERVENTION

Not applicable.

MEASUREMENTS

Survey assessing characteristics of cannabis use.

RESULTS

Approximately 15% (N = 83) of survey responders reported using cannabis within the past 3 years. Half (53%) reported using cannabis regularly on a daily or weekly basis, and reported using cannabidiol-only products (46%). The majority (78%) used cannabis for medical purposes only, with the most common targeted conditions/symptoms being pain/arthritis (73%), sleep disturbance (29%), anxiety (24%), and depression (17%). Just over three-quarters reported cannabis "somewhat" or "extremely" helpful in managing one of these conditions, with few adverse effects. Just over half obtained cannabis via a dispensary, and lotions (35%), tinctures (35%), and smoking (30%) were the most common administration forms. Most indicated family members (94%) knew about their cannabis use, about half reported their friends knew, and 41% reported their healthcare provider knowing. Sixty-one percent used cannabis for the first time as older adults (aged ≥61 years), and these users overall engaged in less risky use patterns (e.g., more likely to use for medical purposes, less likely to consume via smoking).

CONCLUSION

Most older adults in the sample initiated cannabis use after the age of 60 years and used it primarily for medical purposes to treat pain, sleep disturbance, anxiety, and/or depression. Cannabis use by older adults is likely to increase due to medical need, favorable legalization, and attitudes.

Natural Products as Modulators of CES1 Activity

Carboxylesterase (CES) 1 is the predominant esterase expressed in the human liver and is capable of catalyzing the hydrolysis of a wide range of therapeutic agents, toxins, and endogenous compounds. Accumulating studies have demonstrated associations between the expression and activity of CES1 and the pharmacokinetics and/or pharmacodynamics of CES1 substrate medications (e.g., methylphenidate, clopidogrel, oseltamivir). Therefore, any perturbation of CES1 by coingested xenobiotics could potentially compromise treatment. Natural products are known to alter drug disposition by modulating cytochrome P450 and UDP-glucuronosyltransferase enzymes, but this issue is less thoroughly explored with CES1. We report the results of a systematic literature search and discuss natural products as potential modulators of CES1 activity. The majority of research reports reviewed were in vitro investigations that require further confirmation through clinical study. Cannabis products (Δ 9-tetrahydrocannabinol, cannabidiol, cannabinol); supplements from various plant sources containing naringenin, quercetin, luteolin, oleanolic acid, and asiatic acid; and certain traditional medicines (danshen and zhizhuwan) appear to pose the highest inhibition potential. In addition, ursolic acid, gambogic acid, and glycyrrhetic acid, if delivered intravenously, may attain high enough systemic concentrations to significantly inhibit CES1. The provision of a translational interpretation of in vitro assessments of natural product actions and interactions is limited by the dearth of basic pharmacokinetic data of the natural compounds exhibiting potent in vitro influences on CES1 activity. This is a major impediment to assigning even potential clinical significance. The modulatory effects on CES1 expression after chronic exposure to natural products warrants further investigation. SIGNIFICANCE STATEMENT: Modulation of CES1 activity by natural products may alter the course of treatment and clinical outcome. In this review, we have summarized the natural products that can potentially interact with CES1 substrate medications. We have also noted the limitations of existing reports and outlined challenges and future directions in this field.

Cannabidiol Modulates the Motor Profile and NMDA Receptor-related Alterations Induced by Ketamine

Cannabidiol (CBD) is a non-addictive ingredient of cannabis with antipsychotic potential, while ketamine (KET), an uncompetitive NMDA receptor inhibitor, has been extensively used as a psychotomimetic. Only few studies have focused on the role of CBD on the KET-induced motor profile, while no study has investigated the impact of CBD on KET-induced alterations in NMDA receptor subunit expression and ERK phosphorylation state, in brain regions related to the neurobiology and treatment of schizophrenia. Therefore, the aim of the present study is to evaluate the role of CBD on KET-induced motor response and relevant glutamatergic signaling in the prefrontal cortex, the nucleus accumbens, the dorsal and ventral hippocampus. The present study demonstrated that CBD pre-administration did not reverse KET-induced short-lasting hyperactivity, but it prolonged it over time. CBD alone decreased motor activity at the highest dose tested (30 mg/kg) while KET increased motor activity at the higher doses (30, 60 mg/kg). Moreover, KET induced regionally-dependent alterations in NR1 and NR2B expression and ERK phosphorylation that were reversed by CBD pre-administration. Interestingly, in the nucleus accumbens KET per se reduced NR2B and p-ERK levels, while the CBD/KET combination increased NR2B and p-ERK levels, as compared to control. This study is the first to show that CBD prolongs KET-induced motor stimulation and restores KET-induced effects on glutamatergic signaling and neuroplasticity-related markers. These findings contribute to the understanding of CBD effects on the behavioral and neurobiological profiles of psychotogenic KET.

Potential Pharmacokinetic Drug-Drug Interactions between Cannabinoids and Drugs Used for Chronic Pain

Choosing an appropriate treatment for chronic pain remains problematic, and despite the available medication for its treatment, still, many patients complain about pain and appeal to the use of cannabis derivatives for pain control. However, few data have been provided to clinicians about the pharmacokinetic drug-drug interactions of cannabinoids with other concomitant administered medications. Therefore, the aim of this brief review is to assess the interactions between cannabinoids and pain medication through drug transporters (ATP-binding cassette superfamily members) and/or metabolizing enzymes (cytochromes P450 and glucuronyl transferases).

High Doses of Δ9-Tetrahydrocannabinol Might Impair Irinotecan Chemotherapy: A Review of Potentially Harmful Interactions

This review proposes the hypothesis that the effectiveness of irinotecan chemotherapy might be impaired by high doses of concomitantly administered Δ⁹-tetrahydrocannabinol (THC). The most important features shared by irinotecan and THC, which might represent sources of potentially harmful interactions are: first-pass hepatic metabolism mediated by cytochrome P450 (CYP) enzyme CYP3A4; glucuronidation mediated by uridine diphosphate glycosyltransferase (UGT) enzymes, isoforms 1A1 and 1A9; transport of parent compounds and their metabolites via canalicular ATP-binding cassette (ABC) transporters ABCB1 and ABCG2; enterohepatic recirculation of both parent compounds, which leads to an extended duration of their pharmacological effects; possible competition for binding to albumin; butyrylcholinesterase (BChE) inhibition by THC, which might impair the conversion of parent irinotecan into the SN-38 metabolite; mutual effects on mitochondrial dysfunction and induction of oxidative stress; potentiation of hepatotoxicity; potentiation of genotoxicity and cytogenetic effects leading to genome instability; possible neurotoxicity; and effects on bilirubin. The controversies associated with the use of highly concentrated THC preparations with irinotecan chemotherapy are also discussed. Despite all of the limitations, the body of evidence provided here could be considered relevant for human-risk assessments and calls for concern in cases when irinotecan chemotherapy is accompanied by preparations rich in THC.

Cannabis tourist destinations: risk for vulnerable travellers with pre-existing mental disorders

In recent years, more countries have decriminalized and legalized cannabis, and have become cannabis tourism destinations. Little has been published about individuals with pre-existing mental health disorders who use cannabis during travel. Health professionals should pay greater attention to cannabis use among vulnerable travellers before, during, and after their travel.

Herbal Preparations of Medical Cannabis: A Vademecum for Prescribing Doctors

Cannabis has been used for centuries for therapeutic purposes. In the last century, the plant was demonized due to its high abuse liability and supposedly insufficient health benefits. However, recent decriminalization policies and new scientific evidence have increased the interest in cannabis therapeutic potential of cannabis and paved the way for the release of marketing authorizations for cannabis-based products. Although several synthetic and standardized products are currently available on the market, patients’ preferences lean towards herbal preparations, because they are easy to handle and self-administer. A literature search was conducted on multidisciplinary research databases and international agencies or institutional websites. Despite the growing popularity of medical cannabis, little data is available on the chemical composition and preparation methods of medical cannabis extracts. The authors hereby report the most common cannabis preparations, presenting their medical indications, routes of administration and recommended dosages. A practical and helpful guide for prescribing doctors is provided, including suggested posology, titration strategies and cannabinoid amounts in herbal preparations obtained from different sources of medical cannabis.

Serious adverse effects of cannabidiol (CBD): a review of randomized controlled trials

INTRODUCTION

Recent trials using cannabidiol (CBD) have shown that most acute and prolonged adverse effects of CBD are mild to moderate, with rare serious adverse effects (SAEs). This review focused on analyzing SAEs of CBD and their possible relation to drug-drug interactions.

AREAS COVERED

We systematically analyzed the SAEs reported in randomized controlled trials (RCTs) involving the administration of oral CBD for at least 1 week in both healthy volunteers and clinical samples.

EXPERT OPINION

SAEs related to CBD in RCT are rare and include mainly elevated transaminases, convulsion, sedation, lethargy, and upper respiratory tract infections. Elevated transaminases are related to concomitant valproate use, while sedation, lethargy, and upper respiratory tract infections are related to concomitant clobazam use. Epileptic patients should be monitored when using CBD concomitantly with these and other antiepileptic drugs for other possible drug-drug interactions.

Potential Adverse Drug Events with Tetrahydrocannabinol (THC) Due to Drug-Drug Interactions

Tetrahydrocannabinol (THC) is the primary psychoactive ingredient in cannabis. While the safety of THC and cannabis has been extrapolated from millennia of recreational use, medical marijuana programs have increased exposure among medically complex individuals with comorbid conditions and many co-prescribed medications. Thus, THC should be recognized as a pharmacologically complex compound with potential for drug–drug interactions and adverse drug events. This review summarizes potential adverse drug events related to THC when combined with other medications. Metabolic drug–drug interactions are primarily due to THC conversion by CYP3A4 and CYP2C9, which can be impacted by several common medications. Further, CYP2C9 polymorphisms are highly prevalent in certain racial groups (up to 35% in Caucasians) and increase the bioavailability of THC. THC also has broad interactions with drug-metabolizing enzymes and can enhance adverse effects of other medications. Pharmacodynamic interactions include neurological effects, impact on the cardiovascular system, and risk of infection. General clinical recommendations for THC use include starting with low doses and titrating to desired effects. However, many interactions may be unavoidable, dose-limiting, or a barrier to THC-based therapy. Future work and research must establish sufficient data resources to capture medical marijuana use for such studies. Meanwhile, clinicians should balance the potential risks of THC and cannabis and the lack of strong evidence of efficacy in many conditions with patient desires for alternative therapy.

Hyperkinetic reaction to dihydrocodeine

A young man was using dihydrocodeine analgesia for ear pain having had suppurative otitis media. He attended the emergency department with restlessness and twitching movements in his arms and legs. He had fever with otherwise normal vital signs. He had no signs of cerebellar pathology. Investigations were normal. The working diagnosis was of hyperkinetic reaction to dihydrocodeine. Symptoms resolved within 48 hours of withdrawing the drug. Serotonin toxicity is a rare side effect of dihydrocodeine. There is a theoretical basis for increased side effects when taken with cannabidiol-based substances.

The influence of carboxylesterase 1 polymorphism and cannabidiol on the hepatic metabolism of heroin

Heroin (diamorphine) is a highly addictive opioid drug synthesized from morphine. The use of heroin and incidence of heroin associated overdose death has increased sharply in the US. Heroin is primarily metabolized via deacetylation (hydrolysis) forming the active metabolites 6-monoacetylmorphine (6-MAM) and morphine. A diminution in heroin hydrolysis is likely to cause higher drug effects and toxicities. In this study, we sought to determine the contribution of the major hepatic hydrolase carboxylesterase 1 (CES1) to heroin metabolism in the liver as well as the potential influence of one of its known genetic variants, G143E (rs71647871). Furthermore, given the potential therapeutic application of cannabidiol (CBD) for heroin addiction and the frequent co-abuse of cannabis and heroin, we also assessed the effects of CBD on heroin metabolism. In vitro systems containing human liver, wild-type CES1, and G143E CES1 S9 fractions were utilized in the assessment. The contribution of CES1 to the hydrolysis of heroin to 6-MAM was determined as 3.66%, and CES1 was unable to further catalyze 6-MAM under our assay conditions. The G143E variant showed a 3.2-fold lower intrinsic clearance of heroin as compared to the WT. CBD inhibited heroin and 6-MAM hydrolysis in a reversible manner, with IC₅₀s of 14.7 and 12.1 μM, respectively. Our study results suggested only minor involvement of CES1 in heroin hydrolysis in the liver. Therefore, the G143E variant is unlikely to cause significant impact despite a much lower hydrolytic activity. CBD exhibited potent in vitro inhibition toward both heroin and 6-MAM hydrolysis, which may be of potential clinical relevance.