Cannabinoid Poisoning-Related Emergency Department Visits and Inpatient Hospitalizations in Kentucky, 2017 to 2019.

Background and objectives: Cannabis is the most used federally illicit substance. Due to widespread medicinal use and state-level legalization, public perceptions of cannabis have shifted toward the assumption that cannabis is safe. However, cannabinoids can cause adverse medical complications that may lead people to seek treatment. This study characterized cannabinoid poisoning-related medical encounters, poisoning involving cannabinoids and other psychoactive substances, and cannabinoid poisoning-related cardiac complications. Methods: Administrative billing data for emergency department visits and inpatient hospitalizations in acute care facilities with a discharge date from January 1, 2017 to December 31, 2019 were used to characterize cannabinoid poisoning events in Kentucky, identified by ICD-10-CM diagnosis code T40.7X. Results: There were 1,490 encounters of cannabinoid poisoning; patients were primarily non-Hispanic White males, ages 15-44, who had Medicaid and lived in a metropolitan area. Of those, 31.21% involved poisoning with a second psychoactive substance, primarily stimulants and/or opioids, and 17.72% experienced a cardiac complication. Cannabinoid-polydrug poisoning was associated with inpatient treatment (χ2=199.18, p < 0.001) and cardiac complications (χ2=4.58, p < 0.001). Discussion and Conclusions: These results are consistent with other state-level data. Patients who were diagnosed with cannabis-polydrug poisoning, compared to cannabis alone poisoning, had greater odds of hospital admission and cardiac complications, and longer length of hospital stays. Scientific Significance: The health risks of cannabinoid use must be more broadly recognized, while timely and accurate data need to be shared to guide policies on cannabis access. Future research on cannabinoid poisoning should consider the involvement of other psychoactive drugs.

A randomized, double-blind, placebo-controlled study of the kappa opioid receptor antagonist, CERC-501, in a human laboratory model of smoking behavior.

Preclinical data indicate that selective kappa opioid receptor antagonists reduce nicotine self-administration and withdrawal symptoms. The aim of the current study was to determine whether treatment with CERC-501, an orally available, potent, and selective kappa opioid receptor antagonist, could alleviate nicotine withdrawal and craving and mitigate mood alterations associated with nicotine withdrawal in humans. Healthy, adult cigarette smokers were enrolled into this randomized, multisite, double-blind, placebo-controlled, crossover study. Participants completed two 8-day treatment phases during which they received either CERC-501 (15 mg, p.o., once daily) or placebo. On the seventh day of each dosing phase, participants were admitted as inpatients for an 18-hour cigarette abstinence period followed by experimental testing. The primary outcome measures were (a) performance on the McKee Smoking Lapse test (ie, latency to smoke in exchange for money) and (b) number of cigarettes self-administered during a 60-minute ad lib smoking period. Other outcomes included measures of craving, mood, anxiety, nicotine withdrawal, and subjective effects of cigarette smoking. A total of 71 participants who smoked an average of approximately 23 cigarettes per day were enrolled, and 56 subjects completed the study. CERC-501 was well tolerated, but it did not significantly alter the latency to start smoking (CERC-501: 16.5 min vs placebo: 17.7 min) or the number of cigarettes smoked (CERC-501: 3.3 cigarettes vs placebo: 3.1 cigarettes). Compared with placebo, CERC-501 also did not affect cigarette craving, mood, anxiety, nicotine withdrawal, or subjective effects of smoking. These findings do not support a role for CERC-501 in the treatment of nicotine use disorder.

A Pharmacokinetic Study Examining Acetazolamide as a Novel Adherence Marker for Clinical Trials.

RATIONALE: Accurate assessment of medication adherence is critical for determination of medication efficacy in clinical trials, but most current methods have significant limitations. This study tests a subtherapeutic (microdose) of acetazolamide as a medication ingestion marker because acetazolamide is rapidly absorbed and excreted without metabolism in urine and can be noninvasively sampled. METHODS: In a double-blind, placebo-controlled, residential study, 10 volunteers received 15 mg oral acetazolamide for 4 consecutive days. Acetazolamide pharmacokinetics were assessed on day 3, and its pharmacokinetic and pharmacodynamic interactions with a model medication (30 mg oxycodone) were examined on day 4. The rate of acetazolamide elimination into urine was followed for several days after dosing cessation. RESULTS: Erythrocyte sequestration (half-life = 50.2 ± 18.5 h, mean ± SD, n = 6), resulted in the acetazolamide microdose exhibiting a substantially longer plasma half-life (24.5 ± 5.6 hours, n = 10) than previously reported for therapeutic doses (3-6 hours). After cessation of dosing, the rate of urinary elimination decreased significantly (F3,23 = 247: P < 0.05, n = 6) in a predictable manner with low intersubject variability and a half-life of 16.1 ± 3.8 h (n = 10). For each of 4 consecutive mornings after dosing cessation, the rates of urinary acetazolamide elimination remained quantifiable.There was no overall effect of acetazolamide on the pharmacodynamics, Cmax, Tmax, or elimination half-life of the model medication tested. Acetazolamide may have modestly increased overall oxycodone exposure (20%, P < 0.05) compared with one of the 2 days when oxycodone was given alone, but there were no observed effects of acetazolamide on oxycodone pharmacodynamic responses. CONCLUSIONS: Coformulation of a once-daily trial medication with an acetazolamide microdose may allow estimation of the last time of medication consumption for up to 96 hours postdose. Inclusion of acetazolamide may therefore provide an inexpensive new method to improve estimates of medication adherence in clinical trials.

Pharmacodynamic effects of oral oxymorphone: abuse liability, analgesic profile and direct physiologic effects in humans.

Oxymorphone is a semisynthetic µ-opioid agonist, marketed as a prescription analgesic purported to be twice as potent as oxycodone for pain relief. Oral formulations of oxymorphone were reintroduced in the United States in 2006 and reports of abuse ensued; however, there are limited data available on its pharmacodynamic effects. The current study aimed to examine the direct physiologic effects, relative abuse liability, analgesic profile and overall pharmacodynamic potency of oxymorphone in comparison with identical doses of oxycodone. Healthy, non-dependent opioid abusers (n = 9) were enrolled in this within-subject, double-blind, placebo-controlled, 3-week inpatient study. Seven experimental sessions (6.5 hours) were conducted, during which an oral dose of immediate-release formulations of oxymorphone (10, 20 and 40 mg), oxycodone (10, 20 and 40 mg) or placebo was administered. An array of physiologic, abuse liability and experimental pain measures was collected. At identical doses, oxymorphone produced approximately twofold less potent effects on miosis, compared with oxycodone. Oxymorphone also produced lesser magnitude effects on measures of respiratory depression, two experimental pain models and observer-rated agonist effects. However, 40 mg of oxymorphone was similar to 40 mg of oxycodone on several abuse-related subjective ratings. Formal relative potency analyses were largely invalid because of the substantially greater effects of oxycodone. Overall, oxymorphone is less potent on most pharmacodynamic measures, although at higher doses, its abuse liability is similar to oxycodone. These data suggest that the published clinical equianalgesic estimates may not be consistent with the observed direct physiologic effects of opioids, results of experimental pain models or abuse liability measures, as assessed in the human laboratory.

A dose-ranging study of the physiological and self-reported effects of repeated, rapid infusion of remifentanil in people with opioid use disorder and physical dependence on fentanyl.

RATIONALE: Understanding mechanisms of drug use decisions will inform the development of treatments for opioid use disorder (OUD). Decision-making experiments using neurobehavioral approaches require many trials or events of interest for statistical analysis, but the pharmacokinetics of most opioids limit dosing in humans. OBJECTIVES: This experiment characterized the effects of repeated infusions of the ultra-short acting opioid remifentanil in people with OUD and physical opioid dependence. METHODS: An inpatient study using a within-subjects, single-blind, escalating, within-session, pre-post design was conducted. Seven (3 female) subjects were maintained on oral oxycodone (40-60 mg, 4x/day = 160-240 total mg/day) for seven days prior to the dose-ranging session. Subjects received infusions of three ascending remifentanil doses (0.03, 0.1, 0.3 mcg/kg/infusion in 2 subjects; 0.1, 0.3, 1.0 mcg/kg/infusion in 5 subjects) every minute for 40 min per dose, with infusions administered over 5 s to model naturalistic delivery rates. End tidal carbon dioxide, respiration rate, oxygen saturation (SpO2) and heart rate were measured continuously. Blood pressure (BP), pupil diameter and self-reported drug effects were measured every 5 min. RESULTS: Pupil diameter, SpO2 and systolic BP decreased, and ratings on prototypic subjective effects questionnaire items increased, as a function of remifentanil dose. The number of infusions held because of sedation or physiological parameters exceeding predetermined cutoffs also increased with dose. CONCLUSIONS: This experiment established doses and procedures for the safe delivery of rapid, repeated remifentanil infusions to individuals with OUD and physical fentanyl dependence, which can be applied to the mechanistic study of opioid use decisions.

LC-MS/MS quantification of Δ8-THC, Δ9-THC, THCV ISOMERS and their main metabolites in human plasma.

BACKGROUND: In recent years, potential therapeutic applications of several different cannabinoids, such as Δ9-tetrahydrocannabinol (Δ9-THC), its isomer Δ8-THC and Δ9-tetrahydrocannabivarin (Δ9-THCV), have been investigated. Nevertheless, to establish dose-effect relationship and to gain knowledge of their pharmacokinetics and metabolism, sensitive and specific analytical assays are needed to measure these compounds in patients. For this reason, we developed and validated an online extraction high-performance liquid chromatography- tandem mass spectrometry (LC/LC-MS/MS) method for the simultaneous quantification of 13 cannabinoids and metabolites including the Δ8 and Δ9 isomers of THC, THCV and those of their major metabolites in human plasma. METHODS: Plasma was fortified with cannabinoids at varying concentrations within the working range of the respective compound and 200 µL were extracted using a simple one-step protein precipitation procedure. The extracts were analyzed using online trapping LC/LC-atmospheric pressure chemical ionization (APCI)-MS/MS running in the positive multiple reaction monitoring (MRM) mode. RESULTS: The lower limit of quantification ranged from 0.5 to 2.5 ng/mL and the upper limit of quantification was 400 ng/mL for all analytes. Inter-day analytical accuracy and imprecision ranged from 82.9 to 109% and 4.3 to 20.3% (coefficient of variance), respectively. Of 534 plasma samples following controlled oral administration of Δ8-THCV, 236 were positive for Δ8-THCV (median; interquartile ranges: 3.5 ng/mL; 1.8 - 11.9 ng/mL), 383 for the major metabolite (-)-11-nor-9-carboxy-Δ8-tetrahydrocannabivarin (Δ8-THCV-COOH) (95.4 ng/mL; 20.7 - 328 ng/mL), 260 for (-)-11-nor-9-carboxy-Δ9-tetrahydrocannabivarin (Δ9-THCV-COOH) (5.8 ng/mL; 2.5 - 16.1 ng/mL), 157 for (-)-11-hydroxy-Δ8-tetrahydrocannabivarin (11-OH-Δ8-THCV) (1.7 ng/mL; 1.0 - 3.7 ng/mL), 49 for Δ8-THC-COOH (1.7 ng/mL; 1.4 - 2.3 ng/mL) and 42 for Δ9-THCV (1.3 ng/mL; 0.8 - 1.6 ng/mL). CONCLUSIONS: We developed and validated the first LC/LC-MS/MS assay for the specific quantification of Δ8-THC, Δ9-THC and THCV isomers and their respective metabolites in human plasma. Δ8-THCV-COOH, 11-hydroxy-Δ8-THCV and Δ9-THCV-COOH were the major Δ8-THCV metabolites in human plasma after oral administration of 98.6% pure Δ8-THCV.

A Two-Phase, Dose-Ranging, Placebo-Controlled Study of the Safety and Preliminary Test of Acute Effects of Oral Δ8-Tetrahydrocannabivarin in Healthy Participants.

Introduction: Tetrahydrocannabivarin (THCV) is an understudied cannabinoid that appears to have effects that vary as a function of dose. No human study has evaluated the safety and nature of effects in a wide range of THCV doses. Methods: This was a two-phase, dose-ranging, placebo-controlled trial of the Δ8 isomer of oral THCV in healthy adults. Phase 1 utilized an unblinded, single-ascending dose design (n=3). Phase 2 used a double-blind, randomized, within-participant crossover design (n=18). Participants received single acute doses of placebo and 12.5, 25, 50, 100, and 200 mg of THCV. Safety measures and subjective and cognitive effects were assessed predose and up to 8 h postdose. Results: Most adverse events (AEs; 55/60) were mild. Euphoric mood was the most common AE. The 12.5, 25, and 200 mg doses produced significantly lower minimum times to complete the digit vigilance test (ps=0.01). The 25 mg dose showed elevations on mean ratings of "energetic" at 1-, 2-, and 4-h postdose, but the maximum postdose rating for this dose did not achieve statistical significance relative to placebo ([95% confidence interval]=3.2 [-0.5 to 6.9], p=0.116). The 100 and 200 mg doses showed elevations on ratings of "feel a drug effect" and "like the drug effect." Almost all urine drug screens (78/79) at 8 h postdose in the active THCV conditions tested positive for tetrahydrocannabinol (THC). Conclusion: All THCV doses displayed a favorable safety profile. Several THCV doses showed a preliminary signal for improved sustained attention, but the effect was not dose dependent. Though mild and not associated with impairment, THC-like effects were observed at higher THCV doses. Oral THCV-containing products could lead to positive urine drug screens for THC. ClinicalTrials.gov ID: NCT05210634.

Cannabidiol (CBD) product contamination: Quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) concentrations found in commercially available CBD products.

BACKGROUND: Regulation has not kept pace with the growth of the hemp-derived CBD market. We have evaluated the risk of Δ9-tetrahydrocannabinol (Δ9-THC) contamination in 80 unregulated products with comparison to a regulated control, Epidiolex®. METHODS: Local and national brands of hemp-derived oil products were purchased online and from local retailers in central Kentucky (which carry both national and local brands). These were extracted by solvent extraction and quantified by liquid-chromatography tandem mass-spectrometry (LC-MS/MS) using a validated method. RESULTS: Of the 80 unregulated products and Epidiolex®, Δ9-THC was detected above the limit of quantification (LOQ = 0.005 mg/mL) of the assay in 52 samples, ranging from 0.008 mg/mL to 2.071 mg/mL. Twenty-one of the products tested were labelled as "THC-Free", and 5 of these products contained detectable levels of Δ9-THC ranging from 0.015 mg/mL to 0.656 mg/mL. CONCLUSIONS: Consumers are taking hemp-derived CBD products without understanding the risks of unintentional consumption of Δ9-THC. This accidental use of Δ9-THC could have adverse effects on health and safety as well as potential legal consequences (e.g., child custody, impaired driving), as Δ9-THC drug test findings could impact employment, military, and sport eligibility status.

Label accuracy of unregulated cannabidiol (CBD) products: measured concentration vs. label claim.

BACKGROUND: The legalization of hemp in the USA has led to tremendous growth in the availability of hemp-derived products, particularly cannabidiol (CBD) products. The lack of regulatory oversight in this industry has resulted in the marketing and sale of CBD products with questionable ingredients and quality. The aim of the current study was to examine the CBD content in 80 commercially available hemp-derived CBD products purchased from online and local retailers. Epidiolex® was also included in the study as a positive control. METHODS: Hemp-derived CBD products were selected to represent products readily available to residents of Central Kentucky. The samples were comprised of local and national brands produced in a variety of locations inside and outside of Kentucky. The products were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the analytical findings were compared to the label claims for CBD content. Descriptive statistics and normal-based confidence intervals were calculated using Microsoft Excel. RESULTS: The label claims for CBD content ranged from 7.5 to 60 mg/mL, while LC-MS/MS analysis detected a range of 2.9 to 61.3 mg/mL. Of the 80 products evaluated, 37 contained CBD concentrations that were at least ± 10% different than the concentration listed on the label (range of 0.9 to 30.6 mg/mL from label claim) - 12 products contained < 90%, while 25 products contained > 110%. The degree of concordance for the samples tested using ± 10% tolerance from label claim was 54%. CONCLUSIONS: These data suggest that additional regulation is required to ensure label accuracy as nearly half of the products in this study were not properly labelled (i.e., not within a ± 10% margin of error). Consumers and practitioners should remain cautious of unregulated and often-mislabeled CBD products due to the risks of taking too much CBD (e.g., drug-drug interactions, liver enzyme elevations, increased side effects) and the consequences of taking too little (e.g., no clinical benefits due to underdosing). The results of this study support the continued need for good manufacturing practices and testing standards for CBD products.

Progesterone effects on the discriminative stimulus, subjective and performance effects of triazolam in healthy, premenopausal women.

There is accumulating evidence that sex plays a critical role in drug abuse. Female sex hormones have been shown to affect central nervous system function and modulate the effects of drugs of abuse. For example, γ-aminobutyric acid type A (GABA(A)) receptor function is positively modulated by progesterone metabolites. There is evidence from preclinical in-vitro and in-vivo studies as well as some clinical research suggesting that progesterone and its metabolites may enhance the behavioral effects of benzodiazepines, which also serve as positive modulators of GABA(A) receptors. The purpose of this experiment was to determine the independent and combined discriminative stimulus, subjective and psychomotor effects of progesterone and triazolam in healthy adult premenopausal women. Oral micronized progesterone (100 mg), triazolam (0.06, 0.12 and 0.25 mg/70 kg) and placebo were administered to healthy, premenopausal women (n=9) under conditions of low circulating sex hormones. Triazolam alone functioned as a discriminative stimulus and produced prototypical sedative-like effects (e.g., performance impairment, enhanced reports of sedative effects). Progesterone alone produced sedative-like effects on several subjective and performance measures, and the dose combination effects of progesterone and triazolam on several subjective measures of drug effect were similar to the summation of the two drug effects in isolation. Progesterone did not substitute for or modify the discriminative stimulus effects of triazolam. These results suggest that the parent hormone, progesterone, and triazolam have discordant neuropharmacological mechanisms of action. Additional research is necessary to determine the degree to which neurosteroids influence sex differences in benzodiazepine use and abuse.

Cannabidiol: pharmacology and therapeutic targets.

RATIONALE: Cannabidiol (CBD) products lacking regulatory approval are being used to self-treat a myriad of conditions and for their unsubstantiated health benefits. The scientific evidence supporting these claims largely arises not from controlled clinical trials, but from the recognition that CBD has numerous biological targets. Yet, CBD is commonly consumed and often in over-the-counter products that are unapproved and of unknown composition. Epidiolex® is the only product that has undergone rigorous pharmacokinetic assessment and testing in clinical trials; it was approved as a non-scheduled drug by the U.S. Food and Drug Administration for the treatment of intractable childhood-onset seizures. However, studies investigating CBD for other medical conditions are limited in number and often lack the scientific rigor, controls, or sample sizes required to draw clinically meaningful conclusions. Although Epidiolex® is safe for human consumption, recent changes in regulation of commercially available CBD products have resulted in limited quality control and products marketed with unknown CBD bioavailability. Even scientifically rigorous studies have used different sources of CBD and different suspension vehicles for administration, making it difficult to compare results among studies and resolve mixed outcomes. OBJECTIVES: This paper reviews the molecular targets, pharmacokinetics, and safety and abuse liability of CBD; additionally, the extant evidence on its potential therapeutic effects for neurological disorders, pain, inflammation, conditions related to immune function, psychiatric disorders, and substance use are described.

Δ8-THC: Legal Status, Widespread Availability, and Safety Concerns.

Delta-8-tetrahydrocannabinol (Δ8-THC) is chemically and functionally similar to delta-9-tetrahydrocannabinol (Δ9-THC) (the primary psychoactive cannabinoid in the cannabis plant) and is currently widely available "over-the-counter" across the United States due to unregulated sales. However, these products have a questionable legal status based on current U.S. laws, as Δ8-THC is considered a Schedule I drug by the federal Drug Enforcement Administration (DEA). Despite this designation, Δ8-THC products (e.g., gummies, edibles, oils, and vapes) are largely unregulated and are sold in gas stations, online, and other marketplaces (most often outside of authorized dispensaries) and are marketed as legal hemp products. This problem arises from a purposeful misinterpretation of the 2018 Farm Bill, which some interpret as legalization of non-Δ9-THC cannabinoids (notably, Δ8-THC). The widespread availability of Δ8-THC products has not been without health consequences. The lack of regulation means that there are no required warning labels or packaging protections in place and no mandated laboratory analysis to assure label accuracy or product purity. As Δ8-THC produces physiological and toxicological effects that are similar to Δ9-THC, high-dose exposure of Δ8-THC (e.g., consuming a full bag of Δ8-THC gummies) has resulted in recent reports of medical emergencies, including calls to poison control centers and presentations to emergency departments, with some pediatric patients arriving unconscious and unresponsive. Several states and regulatory agencies have called for legislation to regulate Δ8-THC, but little progress has occurred nationally thus far.

Recent Increase in Methamphetamine Use in a Cohort of Rural People Who Use Drugs: Further Evidence for the Emergence of Twin Epidemics.

Appalachian Kentucky was at the epicenter of the prescription opioid epidemic in the early 2000's. As we enter the third decade of the epidemic, patterns have begun to emerge as people who use drugs (PWUD) transition from use of opioids to other drugs. The purpose of this analysis was to examine longitudinal changes in methamphetamine use in an ongoing cohort of rural people who use drugs (PWUD) in Appalachian Kentucky. All but five of the cohort participants (N = 503) reported nonmedical prescription opioid use (NMPOU) at baseline and those 498 are included in this longitudinal analysis encompassing eight waves of data (2008-2020). Past 6-month use of methamphetamine was the dependent variable. Given the correlated nature of the data, mixed effects logistic regression was utilized to examine changes in methamphetamine use over time. Significant increases in methamphetamine use were observed over the past decade in this cohort of PWUD, especially in recent years (2017-2020). Prevalence of recent use at baseline and each of the follow-up visits was as follows: 9.4, 5.6, 5.0, 5.4, 8.1, 6.8, 6.9, and 33.1%, respectively (p < 0.001). On the contrary, significant reductions in NMPO and heroin use were observed in the same time period. The odds of methamphetamine use at the most recent visit were 25.8 times greater than at baseline (95% CI: 14.9, 44.6) and 52.6% of those reporting methamphetamine use reported injecting the drug. These results provide further evidence of "twin epidemics" of methamphetamine use among NMPOU. While problematic on several fronts, of particular concern is the lack of effective treatment options for methamphetamine use disorder. As policies around the opioid epidemic continue to evolve, particular attention should be paid to the surge in stimulant use in opioid-endemic areas.

Acute administration of oxycodone, alcohol, and their combination on simulated driving-preliminary outcomes in healthy adults.

RATIONALE: Epidemiological data indicate that drivers testing positive for an opioid drug are twice as likely to cause a fatal car crash; however, there are limited controlled data available. OBJECTIVES: The primary aim of this study was to assess the effects of a therapeutic dose range of oxycodone alone and in combination with alcohol on simulated driving performance. METHODS: Healthy participants (n = 10) completed this within-subject, double-blind, placebo-controlled, randomized outpatient study. Six 7-h sessions were completed during which oxycodone (0, 5, 10 mg, p.o.) was administered 30 min before alcohol (0, 0.8 g/kg (15% less for women), p.o.) for a total of 6 test conditions. Driving assessments and participant-, observer-rated, psychomotor and physiological measures were collected in regular intervals before and after drug administration. RESULTS: Oxycodone alone (5, 10 mg) did not produce any changes in driving outcomes or psychomotor task performance, relative to placebo (p > 0.05); however, 10 mg oxycodone produced increases in an array of subjective ratings, including sedation and impairment (p < 0.05). Alcohol alone produced driving impairment (e.g., decreased lateral control) (p < 0.05); however, oxycodone did not potentiate alcohol-related driving or subjective effects. CONCLUSIONS: These preliminary data suggest that acute doses of oxycodone (5, 10 mg) do not significantly impair acuity on laboratory-based simulated driving models; however, 10 mg oxycodone produced increases in self-reported outcomes that are not compatible with safe driving behavior (e.g., sedation, impairment). Additional controlled research is needed to determine how opioid misuse (higher doses; parenteral routes of administration) impacts driving risk.

Relative potency of intravenous oxymorphone compared to other µ opioid agonists in humans - pilot study outcomes.

AIMS: Intravenous (IV) misuse of the µ opioid analgesic oxymorphone has caused significant public health harms; however, no controlled data on its IV abuse potential are available. The primary aims of this pilot study were to directly compare IV oxymorphone to IV oxycodone, morphine, and hydromorphone on a subjective measure of drug liking and to assess relative potency. METHODS: Participants (n = 6) with opioid use disorder, physical dependence, and current IV use completed this two-site, within-subject, double-blind, placebo-controlled, inpatient pilot study. During each session, one IV dose (mg/70 kg) was administered: oxymorphone (1.8, 3.2, 5.6, 10, 18, 32), hydromorphone (1.8, 3.2, 5.6, 10, 18), oxycodone (18, 32, 56), morphine (18, 32), and placebo. Data were collected before and for 6 h after dosing. Primary outcomes included safety/physiological effects, subjective reports of drug liking, and relative potency estimates. RESULTS: All active test drugs produced prototypical, dose-related µ opioid agonist effects (e.g., miosis). Oxymorphone was more potent than the comparator opioids on several measures, including drug liking and respiratory depression (p < 0.05). Across abuse-related subjective outcomes, oxymorphone was 2.3-2.8-fold more potent than hydromorphone and 12.5-14-fold more potent than oxycodone (p < 0.05). CONCLUSIONS: Despite the relatively small sample size, this pilot study detected robust oxymorphone effects. Oxymorphone was far more potent than the comparator opioids, particularly on abuse potential outcomes. Overall, these findings may help explain surveillance reports that demonstrate, after adjusting for prescription availability, oxymorphone is injected at the highest frequency, relative to other prescription opioids.

Therapeutic potential of opioid/cannabinoid combinations in humans: Review of the evidence.

The endogenous opioid and cannabinoid receptor systems are widely distributed and co-localized throughout central and peripheral nervous system regions. A large body of preclinical evidence suggests that there are functional interactions between these two systems that may be leveraged to address various health conditions. Numerous animal studies have shown that cannabinoid agonists (e.g., delta-9-tetrahydrocannabinol [Δ9-THC]) enhance the analgesic effects of µ-opioid analgesics as evidenced by decreasing the opioid dose required for analgesia (i.e., opioid sparing) and extending the duration of the opioid analgesia. In contrast, controlled human laboratory studies and clinical trials have not demonstrated robust analgesic or opioid-sparing effects from opioid-cannabinoid combinations. Meta-analyses of the literature (clinical trials, controlled laboratory studies; some non-controlled studies/case reports) have examined the effects of cannabis/cannabinoids for pain relief in those taking a wide variety of analgesics, including prescription opioid medications. These data do not strongly support the use of cannabinoids for chronic pain nor do prospective studies demonstrate significant cannabinoid-mediated opioid-sparing effects. Preclinical studies have also suggested a role for cannabinoids for the treatment of opioid withdrawal. Controlled laboratory and clinical studies suggest that there may be a modest signal for Δ9-THC to suppress some opioid signs and symptoms but they are not completely ameliorated and there may also be concerns around safety of Δ9-THC administration in a state of heightened autonomic arousal as occurs with opioid withdrawal. Despite anecdotal and correlational reports suggesting a benefit of cannabis on reducing opioid overdose, there is no strong data supporting this contention and emerging reports have conflicting results. In summary, there is a groundswell of public advocacy supporting the use of cannabis and cannabinoids to replace opioid analgesics or to reduce opioid use; however, the extant controlled clinical data do not support the role of cannabinoids for opioid replacement or opioid-sparing effects when treating opioid use disorder or chronic pain.

Cannabinoid modulation of opioid analgesia and subjective drug effects in healthy humans.

RATIONALE: Dozens of preclinical studies have reported cannabinoid agonist potentiation of the analgesic effects of µ-opioid agonists. OBJECTIVES: The aim of this study was to determine if a cannabinoid agonist could potentiate opioid analgesia in humans using several laboratory pain models. METHODS: Healthy participants (n = 10) with/out current drug use/pain conditions completed this within-subject, double-blind, placebo-controlled, randomized outpatient study. Nine 8-h sessions were completed during which dronabinol (0, 2.5, 5 mg, p.o.) was administered 1 h before oxycodone (0, 5, 10 mg, p.o.) for a total of 9 test conditions. Outcomes included sensory threshold and tolerance from four experimental pain models (cold pressor, pressure algometer, hot thermode, cold hyperalgesia), along with participant- and observer-rated, performance and physiological effects. RESULTS: Oxycodone produced miosis (p < 0.05) and analgesic responses (e.g., pressure algometer [p < 0.05]), while dronabinol did not (p > 0.05). Depending on the dose combination, dronabinol attenuated or did not alter oxycodone analgesia; for example, dronabinol (2.5 mg) decreased the analgesic effects of oxycodone (10 mg) on pressure tolerance. Conversely, dronabinol increased oxycodone subjective effects (e.g., drug liking) (p < 0.05); oxycodone (5 mg) ratings of "high" were potentiated by 5 mg dronabinol (p < 0.05; placebo = 1.1 [± 0.7]; 5 mg oxycodone = 4.7 [± 2.2]; 5 mg dronabinol = 9.9 [± 8.4]; 5 mg oxycodone + 5 mg dronabinol = 37.4 [± 11.3]). CONCLUSIONS: This study indicates that dronabinol did not enhance the analgesic effects of oxycodone and increased abuse- and impairment-related subjective effects. These data suggest that dronabinol may not be an effective or appropriate opioid adjuvant; it could potentially increase opioid dose requirements, while increasing psychoactive opioid effects.

Modulation of the discriminative stimulus effects of triazolam across the menstrual cycle phase in healthy pre-menopausal women.

Pre-clinical studies indicate that changes in progesterone levels across menstrual cycle phases modulate the behavioral effects of sedative drugs acting at GABA(A) receptor sites. In this study, seven healthy women learned to discriminate triazolam (0.25 mg/70 kg) from placebo. After acquiring the discrimination, a range of triazolam doses (0.00, 0.06, 0.12 and 0.25 mg/70 kg) was tested during the early follicular and mid-luteal menstrual cycle phases. During the mid-luteal phase, when progesterone levels were elevated, 0.12 mg/70 kg triazolam was identified as the active triazolam training dose (0.25 mg/70 kg), whereas 0.12 mg/70 kg triazolam was identified as placebo during the early follicular phase, when progesterone levels were low. Triazolam engendered prototypical sedative effects on subjective effect, performance and cardiovascular measures that were generally independent of cycle phase. These results suggest that the discriminative stimulus effects of the positive GABA(A) modulator, triazolam, are sensitive to menstrual cycle phase in healthy adult women.

Tobacco use during cannabis cessation: Use patterns and impact on abstinence in a National Drug Abuse Treatment Clinical Trials Network study.

BACKGROUND: It is common for cannabis users to also use tobacco. While data suggest that tobacco users have more difficulty achieving cannabis cessation, secondary analyses of clinical trial data sets may provide insight into the moderating variables contributing to this relationship, as well as changes in tobacco use during cannabis treatment. Those were the aims of this secondary analysis. METHODS: The parent study was a multi-site trial of N-acetylcysteine for cannabis dependence conducted within the National Drug Abuse Treatment Clinical Trials Network. Participants were treatment-seeking adults (ages 18-50) who met criteria for cannabis dependence (N = 302). For cigarette smokers (n = 117), tobacco use was assessed via timeline follow-back and nicotine dependence was assessed via the Fagerström Test for Nicotine Dependence (FTND). Outcome measures included: 1) changes in tobacco use based on treatment assignment, nicotine dependence, and concurrent cannabis reduction/abstinence, and 2) independent associations between nicotine dependence and cannabis abstinence. RESULTS: Cigarette smokers accounted for 39% of the sample (117/302), with a median FTND score of 3.0 (10-point scale). Among those with lower baseline nicotine dependence scores, cigarette smoking was reduced in the active treatment group compared to placebo. Those with moderate/high levels of nicotine dependence showed slight increases in smoking following active treatment. Nicotine dependence did not affect cannabis cessation. CONCLUSIONS: Cigarette smoking during cannabis treatment was affected, but depended on baseline nicotine dependence severity, though dependence levels did not impact cannabis abstinence. Interventions that address both tobacco and cannabis are needed, especially due to an increasing prevalence of cannabis use.