Rate of increase of plasma drug level influences subjective response in humans

Association of Glucagon-Like Peptide-1 Receptor Agonist with Progression to Liver Cirrhosis and Alcohol-Related Admissions in Patients with Alcohol Use Disorder and Diabetes: A Retrospective Cohort Study

AIM

In recent years, use of glucagon-like peptide-1 receptor agonists (GLP-1RA) has exponentially increased due to their beneficial effects on weight loss and cardiovascular outcomes. Lately, some animal studies and observational data suggested that GLP-1RA may be useful in the treatment of alcohol use disorder (AUD). We aim to compare the risk of progression to liver cirrhosis and alcohol-related hospital admission after initiation of GLP-1RA versus dipeptidyl peptidase-4 inhibitors (DPP4i), as the active comparator, in patients with type 2 diabetes mellitus and AUD.

METHODS

We conducted a retrospective propensity score-matched cohort study, utilizing new-user and active comparator design. The study used data from the Veterans Health Administration during fiscal years 2006 to 2021 encompassing adults with AUD who initiated either GLP-1RA or DPP4i prescriptions. Our two co-primary outcomes were progression to cirrhosis (compensated and decompensated cirrhosis) and alcohol-related hospital admission.

RESULTS

The eligible cohort included 9965 GLP-1RA users and 19,688 DPP4i users. After propensity score matching, 7302 pairs were matched on 79 characteristics without residual imbalances. In the propensity score-matched cohort, progression to cirrhosis occurred in 6.6% of GLP-1RA users and 6.0% DPP4i users; odds ratio (OR): 1.1, 95% confidence interval (95% CI): 0.97-1.26. Alcohol-related hospital admission occurred in 1.4% of GLP-1RA users and in 1.7% of DPP4i users (OR: 0.85; 95% CI: 0.65-1.11).

CONCLUSIONS

Use of GLP-1RA in patients with AUD was not associated with beneficial effect on progression to cirrhosis or alcohol-related hospital admission.

Associations of semaglutide with incidence and recurrence of alcohol use disorder in real-world population

Alcohol use disorders are among the top causes of the global burden of disease, yet therapeutic interventions are limited. Reduced desire to drink in patients treated with semaglutide has raised interest regarding its potential therapeutic benefits for alcohol use disorders. In this retrospective cohort study of electronic health records of 83,825 patients with obesity, we show that semaglutide compared with other anti-obesity medications is associated with a 50%-56% lower risk for both the incidence and recurrence of alcohol use disorder for a 12-month follow-up period. Consistent reductions were seen for patients stratified by gender, age group, race and in patients with and without type 2 diabetes. Similar findings are replicated in the study population with 598,803 patients with type 2 diabetes. These findings provide evidence of the potential benefit of semaglutide in AUD in real-world populations and call for further randomized clinicl trials.

Semaglutide and Tirzepatide reduce alcohol consumption in individuals with obesity

Alcohol Use Disorder (AUD) contributes significantly to global mortality. GLP-1 (Glucagon-like peptide-1) and GLP-1/GIP (Glucose-dependent Insulinotropic Polypeptide) agonists, FDA-approved for managing type 2 diabetes and obesity, where the former has shown to effectively reduce the consumption of alcohol in animal models but no reports exist on the latter. In this report, we conducted two studies. In the first study, we conducted an analysis of abundant social media texts. Specifically, a machine-learning based attribution mapping of ~ 68,250 posts related to GLP-1 or GLP-1/GIP agonists on the Reddit platform. Secondly, we recruited participants (n = 153; current alcohol drinkers; BMI ≥ 30) who self-reported either taking Semaglutide (GLP-1 agonist), Tirzepatide (the GLP-1/GIP combination) for ≥ 30 days or, as a control group; no medication to manage diabetes or weight loss for a within and between subject remote study. In the social media study, we report 8 major themes including effects of medications (30%); diabetes (21%); and Weight loss and obesity (19%). Among the alcohol-related posts (n = 1580), 71% were identified as craving reduction, decreased desire to drink, and other negative effects. In the remote study, we observe a significantly lower self-reported intake of alcohol, drinks per drinking episode, binge drinking odds, Alcohol Use Disorders Identification Test (AUDIT) scores, and stimulating, and sedative effects in the Semaglutide or Tirzepatide group when compared to prior to starting medication timepoint (within-subjects) and the control group (between-subjects). In summary, we provide initial real-world evidence of reduced alcohol consumption in people with obesity taking Semaglutide or Tirzepatide medications, suggesting potential efficacy for treatment in AUD comorbid with obesity.

Oral nicotine pouches with an aftertaste? Part 1: screening and initial toxicological assessment of flavorings and other ingredients

Nicotine pouches are oral products that deliver nicotine without containing tobacco. Previous studies mainly focused on the determination of known tobacco toxicants, while yet no untargeted analysis has been published on unknown constituents, possibly contributing to toxicity. Furthermore, additives might enhance product attractiveness. We therefore performed an aroma screening with 48 different nicotine-containing and two nicotine-free pouches using gas chromatography coupled to mass spectrometry, following acidic and basic liquid-liquid extraction. For toxicological assessment of identified substances, European and international classifications for chemical and food safety were consulted. Further, ingredients listed on product packages were counted and grouped by function. Most abundant ingredients comprised sweeteners, aroma substances, humectants, fillers, and acidity regulators. 186 substances were identified. For some substances, acceptable daily intake limits set by European Food Safety Agency (EFSA) and Joint FAO/WHO Expert Committee on Food Additives are likely exceeded by moderate pouch consumption. Eight hazardous substances are classified according to the European CLP regulation. Thirteen substances were not authorized as food flavorings by EFSA, among them impurities such as myosmine and ledol. Three substances were classified by International Agency for Research on Cancer as possibly carcinogenic to humans. The two nicotine-free pouches contain pharmacologically active ingredients such as ashwagandha extract and caffeine. The presence of potentially harmful substances may point to the need for regulation of additives in nicotine-containing and nicotine-free pouches that could be based on provisions for food additives. For sure, additives may not pretend positive health effects in case the product is used.

Two Different Heated Tobacco Products vs. Cigarettes: Comparison of Nicotine Delivery and Subjective Effects in Experienced Users

Heated tobacco products (HTPs) produce aerosol using a different mechanism than tobacco cigarettes, leading to lower emissions of some harmful substances, but also of nicotine as reported by some independent studies. Lower nicotine delivery could lead to compensatory puffing when product use does not sufficiently satisfy cravings. Thus, this three-arm crossover study was conducted to characterize the potential of two different HTPs to deliver nicotine and satisfy cravings compared with conventional cigarettes in users who had already switched to HTPs. Fifteen active, non-exclusive HTP users consumed the study products according to a pre-directed puffing protocol. At predetermined time points, venous blood was sampled and the subjective effects of consumption were assessed. Nicotine delivery by both HTPs was comparable, but significantly lower than that by conventional cigarettes, suggesting a lower addictive potential. Cravings were reduced by all products, with no statistically significant differences between them, despite the different nicotine deliveries. This indicated that HTPs do not necessarily need high nicotine deliveries with high addictive potential, as are characteristic of tobacco cigarettes. These results were followed up on with an ad libitum use study.

Usage Pattern and Nicotine Delivery during Ad Libitum Consumption of Pod E-Cigarettes and Heated Tobacco Products

Many different nicotine delivery products, such as e-cigarettes (e-cigs) or heated tobacco products (HTPs), are available on the market. To better understand these products, it is crucial to learn how consumers use them and how much nicotine they deliver. Therefore, a pod e-cig, an HTP, and a conventional cigarette (CC) were each used by 15 experienced users of the respective product category for 90 min without special use instructions ("ad libitum"). Sessions were video recorded to analyze usage patterns and puff topography. At defined time points, blood was sampled to determine nicotine concentrations, and subjective effects were inquired about using questionnaires. During the study period, the CC and HTP groups averaged the same number of consumption units (both 4.2 units). In the pod e-cig group, the highest number of puffs was taken (pod e-cig 71.9; HTP: 52.2; CC: 42.3 puffs) with the most extended mean puff duration (pod e-cig: 2.8 s; HTP: 1.9 s; CC: 1.8 s). Pod e-cigs were predominantly used with single puffs or in short clusters of 2-5 puffs. The maximum plasma nicotine concentration was highest for CCs, followed by HTPs, and then pod e-cigs with 24.0, 17.7, and 8.0 ng/mL, respectively. Craving was reduced by all products. The results suggest that the high nicotine delivery known for tobacco-containing products (CCs and HTPs) may not be needed for non-tobacco-containing products (pod e-cigs) to satisfy cravings in experienced users.

The impact of caloric availability on eating behavior and ultra-processed food reward

The food environment has changed rapidly and dramatically in the last 50 years. While industrial food processing has increased the safety and stability of the food supply, a rapid expansion in the scope and scale of food processing in the 1980's has resulted in a market dominated by ultra-processed foods. Here, we use the NOVA definition of category 4 ultra-processed foods (UPFs) as they make up around 58% of total calories consumed in the US and 66% of calories in US children. UPFs are formulated from ingredients with no or infrequent culinary use, contain additives, and have a long shelf-life, spending long periods in contact with packaging materials, allowing for the absorption of compounds from those materials. The full implications of this dietary shift to UPFs on human health and disease outcomes are difficult, if not impossible, to quantify. However, UPF consumption is linked with various forms of cancer, increased cardiovascular disease, and increased all-cause mortality. Understanding food choice is, therefore, a critical problem in health research. Although many factors influence food choice, here we focus on the properties of the foods themselves. UPFs are generally treated as food, not as the highly refined, industrialized substances that they are, whose properties and components must be studied. Here, we examine one property of UPFs, that they deliver useable calories rapidly as a potential factor driving UPF overconsumption. First, we explore evidence that UPFs deliver calories more rapidly. Next, we examine the role of the gut-brain axis and its interplay with canonical reward systems, and last, we describe how speed affects both basic learning processes and drugs of abuse.

Pharmacokinetic and subjective assessment of prototype JUUL2 electronic nicotine delivery system in two nicotine concentrations, JUUL system, IQOS, and combustible cigarette

RATIONALE

Electronic nicotine delivery systems and heated tobacco products are noncombustible alternatives for adult smokers. Evidence suggests sufficient nicotine delivery and satisfying effects are necessary to facilitate switching away from smoking; nicotine delivery varies across electronic nicotine delivery systems within limited nicotine concentrations.

OBJECTIVES

To assess the nicotine delivery and subjective effects of prototype JUUL2 System in two nicotine concentrations, currently-marketed US JUUL System ("JUUL"), IQOS-brand heated tobacco product, and combustible cigarettes.

METHODS

Adult smokers (N = 40) completed a 5-arm cross-over product-use laboratory confinement study. Nicotine pharmacokinetics and subjective effects were assessed following use of: (1) JUUL2 prototype 18 mg/mL nicotine; (2) JUUL2 prototype 40 mg/mL; (3) JUUL 59 mg/mL; (4) IQOS 18 mg/g; and (5) usual brand combustible cigarette, each evaluated during ad libitum (10 min) and controlled (5 min, 10 standardized puffs) use.

RESULTS

Nicotine delivery was greatest for combustible cigarettes, followed by JUUL2 prototype 40 mg/mL, IQOS, JUUL2 prototype 18 mg/mL, and JUUL 59 mg/mL. Nicotine delivery from JUUL2 prototype 18 mg/mL was significantly greater than JUUL 59 mg/mL after ad libitum use. JUUL products were significantly more satisfying and effective at reducing craving than IQOS. JUUL2 prototype 40 mg/mL was significantly more aversive than other JUUL products.

CONCLUSIONS

Prototype JUUL2 and JUUL 59 mg/mL products were rated higher than IQOS on subjective measures associated with switching away from smoking. The JUUL2 prototype 40 mg/mL produced aversive responses and would require modifications to be a viable product for adult smokers. Nicotine delivery and subjective responses to JUUL2 prototype 18 mg/mL suggest a product based on this prototype may facilitate increased switching among adult smokers.

Association of partial systemic exposure and abuse potential for opioid analgesics with abuse deterrence labeling claims supporting product-specific guidance

BACKGROUND

Over the past decade, U.S. FDA has approved 10 opioid analgesics in abuse-deterrent formulations (ADFs). ADFs are intended to reduce abuse of a prescription opioid through manipulation of the product to use one or more routes of abuse. Although it is critically needed for evaluation of the abuse deterrent properties of an opioid product, the relationship between systemic exposure and likelihood of abuse of the opioid has not been fully characterized. To fill the current knowledge gap, we have evaluated the association of subjective measures predictive of abuse potential (e.g., scores of "drug liking," "take drug again"), which are referred to as 'pharmacodynamic (PD)' responses for measuring abuse potential, with systemic exposure of the opioid using the data from all the clinical abuse potential trials submitted to FDA in support of the approval of innovator ADFs.

METHODS

Extensive pharmacokinetic (PK) and subjective response data from 11 clinical abuse potential trials in recreational opioid users following oral and nasal administration of intact and manipulated oxycodone, hydrocodone and morphine products from the FDA internal database were utilized for the present analysis. This retrospective study used data collected from January 11^th, 2010 until March 25^th, 2015. The potential relationship between PK metrics, especially those for early exposure measures, and the subjective measures of drug liking and take drug again as PD metrics of abuse potential were explored using linear and logistic regression analyses. Heterogeneity analysis was conducted to assess study-to-study variation and multi-level logistic regression analysis was used to affirm the identified PK-PD relationship based on pooled data.

FINDINGS

Following oral and nasal administration of intact and manipulated opioids, the maximum visual analogue scale (VAS) for Drug Liking was generally achieved no later than the time to peak plasma drug concentration. Both heterogeneity analysis and multi-level logistic regression indicated insignificant inter study variability for the evaluated PK-PD relationships. Duration of Drug Liking response (i.e., VAS ≥ 65) lasted for 2 to 4 h after drug administration. The early portion of the systemic area under the plasma concentration-time curve (AUC), e.g., partial AUCs in the first 3 h and 4 h were found to be associated with abuse potential measures including maximum Drug Liking VAS and maximum Taking Drug Again VAS. Neither a formulation factor (e.g., immediate-release vs. extended-release, intact vs. manipulated) nor a route of administration was identified as a significant factor together with early partial AUCs to predict the probability of maximum Drug Liking or maximum Take Drug Again responses being greater than or equal to 65.

INTERPRETATION

Our assessment indicates that the measure of early systemic drug exposure of opioids is the best predictor of the abuse potential response in recreational opioid users following oral or nasal administration of a single dose of an intact or manipulated abuse deterrent opioids. Our findings support FDA's recommendation of comparative PK studies with early partial AUCs as a supportive PK metric for the assessment of abuse deterrent properties of generic opioid drug products in the general and product-specific guidance's of ADFs.

FUNDING

The study was partially funded by Fiscal Year 2017 Critical Path of the Center for Drug Evaluation and Research at the U.S. Food and Drug Administration.

CANUE: A Theoretical Model of Pain as an Antecedent for Substance Use

BACKGROUND

Pain and substance use are frequently comorbid and have been shown to exert bidirectional effects. Self-medication of pain and distress via substance use is common and can be understood via negative reinforcement, ultimately strengthening the pathway between pain to substance use over time. As such, a testable model of the potentially modifiable candidate mechanisms that underlie the pain to substance use pathway is needed.

PURPOSE

This review proposes a testable model of pain as an antecedent to substance use to guide future research and inform clinical practice.

METHODS

An integrative review of current evidence regarding pain, substance use, and associated risk factors (i.e., negative affect, pain-related attitudes, negative urgency, and substance use outcome expectancies) was conducted.

RESULTS

The Catastrophizing, Anxiety, Negative Urgency, and Expectancy (CANUE) model highlights modifiable risk factors for self-medicating pain with substance use, including increased negative affect and maladaptive pain-related attitudes (i.e., pain catastrophizing, pain anxiety, and fear of pain), negative urgency, and substance-related outcome expectancies for pain relief and enhanced pain coping.

CONCLUSIONS

Targeted behavioral and psychological interventions that address these factors may facilitate more adaptive pain-coping responses, thereby reducing the impacts of pain on substance use. Systematic research is needed to evaluate the validity and clinical utility of this model.

Transdermal Delivery of the Free Base of 3-Fluoroamphetamine: In Vitro Skin Permeation and Irritation Potential

This work aimed to continue our effort in establishing the feasibility of 3-fluoroamphetamine (also known as PAL-353) to be a transdermal drug candidate by studying the delivery of the base form through the human cadaver skin in lieu of the previously investigated salt form, and for the first time using an EPIDERM™-reconstructed human epidermal model to predict the skin irritation potential of PAL-353, in support of development for a matrix-type transdermal delivery system. Passive and enhanced (with chemical permeation enhancers) transdermal delivery were investigated via in vitro permeation studies that were performed on Franz diffusion cells with dermatomed human cadaver skin. After 24 h, PAL-353 free base revealed high passive permeation of 417.49 ± 30.12, 1577.68 ± 165.41, and 4295.16 ± 264.36 μg/cm², with applied formulation concentrations of 5.5 (F1), 20 (F2), and 40 (F3) mg/mL, respectively. Oleyl alcohol produced an approximately threefold steady-state flux enhancement at 5% or 10% w/w but may not be needed as the free base alone provided therapeutically relevant permeation. Further, it was predicted that therapeutically relevant delivery would be unlikely to cause skin irritation using the EPIDERM™-reconstructed human epidermal model. In conclusion, the present study further supported the development of PAL-353 transdermal delivery systems.

The pharmacokinetics of 3-fluoroamphetamine following delivery using clinically relevant routes of administration

3-Fluoroamphetamine (also called PAL-353) is a synthetic amphetamine analog that has been investigated for cocaine use disorder (CUD), yet no studies have characterized its pharmacokinetics (PK). In the present study, we determined the PK of PAL-353 in male Sprague Dawley rats following intravenous bolus injection (5 mg/kg). Plasma samples were analyzed using a novel bioanalytical method that coupled liquid-liquid extraction and LC-MS/MS. The primary PK parameters determined by WinNonlin were a C0 (ng/mL) of 1412.09 ± 196.12 and a plasma half-life of 2.27 ± 0.67 h. As transdermal delivery may be an optimal approach to delivering PAL-353 for CUD, we assessed its PK profile following application of 50 mg of transdermal gel (10% w/w drug over 5 cm2). The 10% w/w gel resulted in a short lag time, sustained delivery, and a rapid clearance in plasma immediately after removal. The rodent PK data were verified by examining in vitro permeation through human epidermis mounted on Franz diffusion cells. An in vitro-in vivo correlation (IVIVC) analysis was performed using the Phoenix IVIVC toolkit to assess the predictive relationship between rodent and human skin absorption/permeation. The in vitro permeation study revealed a dose-proportional cumulative and steady-state flux with ~ 70% of drug permeated. The fraction absorbed in vivo and fraction permeated in vitro showed a linear relationship. In conclusion, we have characterized the PK profile of PAL-353, demonstrated that it has favorable PK properties for transdermal administration for CUD, and provided preliminary evidence of the capacity of rodent data to predict human skin flux.

Changes in taste function and ingestive behavior following bariatric surgery

Bariatric surgery is the most effective treatment for severe obesity and its related comorbidities. Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) are currently the most popular weight-loss surgeries used worldwide. Following these surgeries, many patients self-report changes in taste perception and decreased preference for unhealthy foods. These reported changes might account for increased adherence to healthier diets and successful weight loss after surgeries. However, researchers have used a variety of methodologies to assess patients' reported changes andresults are discrepant. The goal of this review is to summarize the literature regarding changes to taste function and ingestive behavior following RYGB and SG to examine differences in findings by methodology (indirect vs. direct measurements). We focused our review around changes in sweets, fats, and alcohol because most of the documented changes in ingestive behavior post-surgery are related to changes in these dietary items. We found that studies using surveys and questionnaires generally find that subjects self-report changes in taste and decrease their preference and cravings for energy-dense foods (particularly, sweets and high-fats). However, studies using validated sensory techniques that include oral sampling or by using direct food intake measurements find little to no change in subjects' ability to perceive taste or their preference for energy-dense foods. Therefore, reported changes in taste and food preferences are unlikely to be explained by alterations in taste intensity and diet selection, and are rather related to changes in the rewarding value of food. Further, that RYGB, and likely SG, is associated with increased alcohol consumption and arisk to develop an alcohol use disorder) supports the notion that these surgeries alter central circuits of reward that are critical in the regulation of ingestive behavior.

Characterization of locomotor response to psychostimulants in the parthenogenetic marbled crayfish (Procambarus fallax forma virginalis): A promising model for studying the neural and molecular mechanisms of drug addiction

Although scientific research using mammalian models has made great strides in uncovering the enigmatic neural and molecular mechanisms orchestrating the state of drug addiction, a complete understanding has thus far eluded researchers. The complexity of the task has led to the use of invertebrate model systems to complement the research of drug-induced reward in mammalian systems. Invertebrates, such as crayfish, offer excellent model systems to help reveal the underlying mechanisms of drug addiction as they retain the ancestral neural reward circuit that is evolutionarily conserved across taxa, and they possess relatively few, large neurons, laid out in an accessible, modularly organized nervous system. Crayfish offer the benefits of delineated developmental life stages, a large body size suitable for a variety of experimental methods, and stereotyped behaviors. Unique among crayfish is the parthenogenetic marbled crayfish (Procambarus fallax forma virginalis), a species of asexually reproducing, genetically identical clones. With the benefits of reduced individual variation, high fecundity, and easy lab husbandry, the marbled crayfish would make a particularly powerful addition to the animal model repertoire. Here we characterize the locomotor response of juvenile P. f. f. virginalis exposed to the psychostimulant, d-amphetamine sulfate. Custom video-tracking software was used to record the movement patterns of juveniles exposed to water infused with varying concentrations of d-amphetamine sulfate. ANOVA demonstrated that crayfish locomotion was significantly impacted by drug concentration. These psychostimulant effects provide the foundation of P. f. f. virginalis as a model for parsing the neural and molecular mechanisms of drug addiction.

Human Abuse Potential of the New Opioid Analgesic Molecule NKTR-181 Compared with Oxycodone

Objective

Evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of NKTR-181, a novel mu-opioid agonist molecule, relative to oxycodone.

Design

This randomized, single-center, double-blind, active- and placebo-controlled five-period crossover study enrolled healthy, adult, non–physically dependent recreational opioid users.

Setting

Inpatient clinical research site.

Subjects

Forty-two randomized subjects (73.8% male, 81% white, mean age = 25 years).

Methods

The primary objective was to evaluate single orally administered 100, 200, and 400 mg NKTR-181 doses in solution compared with 40 mg oxycodone and placebo solutions using the Drug Liking visual analog scale. Secondary measures included the Drug Effects Questionnaire, Addiction Research Center Inventory/Morphine Benzedrine Group Subscale, Price Value Assessment Questionnaire, Global Assessment of Overall Drug Liking, and Take Drug Again Assessment. Central nervous system mu-opioid effects were assessed using pupillometry. The study included qualifying and treatment phases. Subjects received each of the five treatments using a crossover design.

Results

NKTR-181 at all dose levels had significantly lower Drug Liking E_max than oxycodone (P < 0.0001). Drug Liking scores for oxycodone increased rapidly within 15 minutes and peaked at approximately one hour postdose, whereas Drug Liking (and most secondary abuse potential measures) for all doses of NKTR-181 were comparable with placebo for at least the first hour. Only the 400 mg Drug Liking scores were minimally differentiated vs placebo from one and a half to four hours, but remained significantly lower than oxycodone (P < 0.003). NKTR-181 treatment-related adverse effects were mild and occurred at a lower rate compared with oxycodone.

Conclusions

NKTR-181 demonstrated delayed onset of CNS effects and significantly lower abuse potential scores compared with oxycodone in recreational opioid users.

Proceedings from the 2018 Association for Chemoreception Annual Meeting Symposium: Bariatric Surgery and Its Effects on Taste and Food Selection

This article provides a summary of the topics discussed at the symposium titled "Bariatric Surgery and Its Effects on Taste and Food Selection," which was held at the Fortieth Annual Meeting of the Association for Chemoreception Sciences. Bariatric surgery such as Roux-en-Y gastric bypass (RYGB) is currently one of the most effective treatments available for weight loss and Type 2 diabetes. For this reason, it is of great interest to clinicians as well as to basic scientists studying the controls of feeding and energy balance. Despite the commonly held view by clinicians that RYGB patients change their food preferences away from fats and sugars in favor of less energy dense alternatives such as vegetables, the empirical support for this claim is equivocal. It is currently thought that the taste and palatability of fats and sugars are affected by the surgery. Some key preclinical and clinical findings addressing these issues were evaluated in this symposium.

Preclinical efficacy of an anti-methamphetamine vaccine using E6020 adjuvant

BACKGROUND AND OBJECTIVE

Methamphetamine (MA) substance use disorder (SUD) does not have an efficacious pharmacotherapy. We developed a MA vaccine and investigated its potential to attenuate MA induced responses.

METHODS

We examined a novel adjuvant, E6020, a Toll-like receptor-4 (TLR-4) agonist combined with tetanus-toxoid conjugated to succinyl-methamphetamine (TT-SMA) adsorbed on aluminum hydroxide (alum). Adult BALB/c female mice received the vaccine and booster injections at weeks 0, 3, and 6. The efficacy of the vaccine was assessed by the level and affinity of anti-MA antibodies elicited, its ability to attenuate MA induced locomotor activation and its reduction in the amount of MA entering the brains of vaccinated mice.

RESULTS

The TT-SMA vaccine containing alum and E6020 adjuvant produced anti-MA antibodies with nanomolar affinities and showed threefold greater peak titer levels than without E6020 (700 vs 250 μg/ml). These antibodies significantly decreased MA-induced locomotor activation (p < .05), and reduced the brain (p < .005) MA levels following MA administration in actively immunized mice.

CONCLUSIONS

Thus, this anti-MA vaccine formulated with E6020 demonstrated effective functional protection against behavioral disruptions induced by MA.

SCIENTIFIC SIGNIFICANCE

Together, anti-MA vaccine showing a promising improvement in the efficacy of the vaccine that could be an effective candidate vaccine for methamphetamine use disorder (MUD). Furthermore, combinations of adjuvants may be a tool to design vaccines for MA dependence in humans. (Am J Addict 2019;XX:1-8).

Oral Abuse Potential, Pharmacokinetics, and Safety of Once-Daily, Single-Entity, Extended-Release Hydrocodone (HYD) in Recreational Opioid Users

Objectives. A once-daily, extended-release hydrocodone bitartrate tablet with abuse-deterrent properties (Hysingla ER [HYD]) is available for the treatment of chronic pain in appropriate patients. This study evaluated the oral abuse potential and pharmacokinetics (PK) of HYD intact, chewed, or milled to fine particles in comparison with hydrocodone solution or placebo.

Design. Single-center, double-blind, randomized, five-period, five-treatment crossover study.

Subjects. Healthy adult, nondependent, recreational opioid users.

Methods. Forty subjects received orally administered treatments of hydrocodone 60 mg solution, HYD 60 mg intact, HYD 60 mg chewed, HYD 60 mg milled to fine particles, or placebo, separated by a five- to seven-day washout. Assessments over 36 hours postdose included subjective measures of drug liking and willingness to take drug again (assessed using visual analog scales [VAS]), pupillometry, PK, and safety measures.

Results. Following oral administration, HYD intact, HYD chewed, and HYD fine particles led to significantly lower “at this moment” drug liking compared with hydrocodone solution. HYD intact and chewed were significantly different from hydrocodone solution on overall drug liking, take drug again, and good effects. Pupil constriction, as measured by pupillometry, occurred later with HYD intact and HYD chewed than with hydrocodone solution. Across treatments (hydrocodone solution, HYD fine particles, HYD chewed, and HYD intact, respectively), mean C_max and rate of absorption (C_max/T_max) values decreased, respectively, and median T_max values increased, respectively. Safety was consistent with the known effects of opioid agonists.

Conclusion. HYD demonstrated reduced oral abuse potential compared with hydrocodone solution in healthy adult, nondependent, recreational opioid users.*

Pharmacokinetic and Pharmacodynamic Correlations From 2 Studies Evaluating Abuse Potential of Hydrocodone Extended-Release Tablets

Pharmacokinetic (PK)/pharmacodynamic (PD) correlations were explored in 2 human abuse potential studies of orally and intranasally administered hydrocodone extended-release (ER) 45 mg in healthy, nondependent opioid users. In a crossover study design, subjects received intact hydrocodone ER, finely milled hydrocodone ER, and hydrocodone powder in solution in the oral study and finely milled hydrocodone ER, hydrocodone powder, and finely milled Zohydro® ER in the intranasal study. Spearman ρ² and Pearson r² values were calculated for PD (maximum effect [E_max ] for "at the moment" Drug Liking, Overall Drug Liking, and Take Drug Again visual analog scales [VAS]) vs PK (partial area under the concentration-time curve [AUC], maximum drug concentration [C_max ], time to C_max [T_max ], and abuse quotient [PK AQ; C_max /T_max ]) for all treatments. In the oral study, correlations were strongest between E_max of "at the moment" Drug Liking and PK parameters (C_max [ρ²  = 0.4446], PK AQ [ρ²  = 0.5179], T_max [ρ²  = 0.5093], and early systemic exposure [ρ²  = 0.4782]). For Overall Drug Liking and Take Drug Again VAS, ρ² values for correlations with PK parameters ranged from 0.2620 to 0.3637. In the intranasal study, no clear correlations between PK and PD parameters were apparent.

Human abuse potential studies of abuse-deterrent opioids: lessons from oral and intranasal studies with morphine abuse-deterrent, extended-release, injection-molded tablets

BACKGROUND

The development and use of abuse-deterrent (AD) opioids is part of a multifaceted strategy to reduce misuse, abuse, and diversion, while maintaining access for patients with severe pain who may benefit from their analgesic efficacy. Morphine AD, extended-release (ER), injection-molded tablets (morphine-ADER-IMT; ARYMO ER; Egalet US Inc., Wayne, PA) is approved by the FDA as an AD opioid. As part of the characterization of AD opioids, assessments of their human abuse potential (HAP) are required. Evidence from HAP studies can guide clinicians on the use of AD opioids in clinical practice. Herein, we describe HAP study design, and how specific AD features can impact the conduct of a study and interpretation of its results.

OBJECTIVES

To review the design features and results of the oral and intranasal HAP studies with morphine-ADER-IMT in order to improve the understanding of key elements of HAP studies of AD opioids.

CONCLUSIONS

Results from HAP studies with morphine-ADER-IMT and other AD opioids suggest that key study design features include the release profile (immediate-release vs extended-release) of the positive control, study drug doses, and the way the products are manipulated. These elements can directly impact the outcomes of the pharmacokinetic and pharmacodynamic (e.g. Maximum Drug Liking, Overall Drug Liking, and Take Drug Again) results. When evaluating HAP studies, it is important to understand study design features to assist in the interpretation of the results and understand the clinical relevance of the data to help guide clinical decision-making about the use of AD opioids.

Relative Bioavailability, Intranasal Abuse Potential, and Safety of Benzhydrocodone/Acetaminophen Compared with Hydrocodone Bitartrate/Acetaminophen in Recreational Drug Abusers

Objectives

Benzhydrocodone is a hydrocodone prodrug that has been combined with acetaminophen (APAP) in a novel immediate-release analgesic. This study evaluated the relative bioavailability, intranasal abuse potential, and safety of benzhydrocodone/APAP compared with commercially available hydrocodone bitartrate (HB)/APAP.

Design

Single-center, randomized, double-blind, double-dummy, two-part study comprising a Dose Selection (Part A) phase and a Main Study (Part B) phase.

Setting

Clinical research site.

Subjects

Healthy adult, nondependent, recreational opioid users with a history of intranasal abuse.

Methods

Subjects (N = 42) in Part B received five in-clinic treatments consisting of intranasal and oral benzhydrocodone/APAP (13.34/650 mg), intranasal and oral hydrocodone/APAP (15/650 mg), and placebo, with four or more days of washout between treatments. Pharmacodynamic assessments included subjective effects of Drug Liking, Overall Drug Liking, and Take Drug Again (assessed on visual analog scale [VAS]), as well as nasal irritation. Pharmacokinetics and safety were also assessed.

Results

Hydrocodone C_max was 11% lower for intranasal benzhydrocodone/APAP vs intranasal HB/APAP (P = 0.0027). Early cumulative hydrocodone exposures for intranasal benzhydrocodone/APAP through 0.5, 1, and 2 hours were reduced by approximately 50%, 29%, and 15%, respectively (P ≤ 0.0024). Correspondingly, Drug Liking VAS values up to two hours postdose were significantly lower for intranasal benzhydrocodone/APAP vs intranasal HB/APAP (P ≤ 0.0079), although peak Drug Liking VAS (E_max) scores were not different (P = 0.2814). Adverse nasal effects were more frequent for intranasal benzhydrocodone/APAP vs intranasal HB/APAP.

Conclusions

Reduced hydrocodone exposure and drug liking at early time intervals, coupled with adverse nasal effects, can be expected to provide a level of deterrence to the intranasal route of abuse for benzhydrocodone/APAP.

Nicotine delivery efficiency of first- and second-generation e-cigarettes and its impact on relief of craving during the acute phase of use

Knowledge about the change in blood nicotine concentrations during the first five minutes (acute phase) of e-cigarette vaping is important to determine whether the used product has a dependence potential or may be an efficient nicotine replacement product. To address this issue, we monitored blood nicotine levels during the acute phase in volunteers using disposable cigalikes (CLs) and a tank model (TM) and compared them with blood nicotine levels in subjects using a tobacco cigarette (TC). In parallel, heart rate changes were continually measured and withdrawal symptoms and craving were assessed with the Questionnaire on Smoking Urges before and immediately after the vaping/smoking sessions. Additionally, at the end of each session negative health effects were rated on a visual analog scale. After five minutes of e-cigarette or TC use, the mean nicotine plasma concentrations were as follows: CLs, 5.5ng/ml; TM, 9.3ng/ml; TC, 17.1ng/ml. Nicotine levels increased significantly faster in the first 4min of consuming a TC than with the CLs and the TM. The highest rate of increase in nicotine concentration was found with the TC (6.8ng/ml) and TM (2.3ng/ml) between the 1st and 2nd minute, whereas the CLs showed comparatively small changes in the amount delivered over the five minutes. Withdrawal and craving for smoking decreased with the TM by the same amount as with the TC, even though less nicotine was delivered to the blood and considerably fewer side effects occurred. The heart rate of TM users was also markedly lower than that of the TC users. Unlike CLs, TM e-cigarettes represent an effective source of nicotine and might be used as an alternative nicotine replacement product to aid smoking cessation. However, nicotine plasma levels observed in TM users after short-time vaping have also the potential to produce and sustain nicotine addiction.

Inhalation of Alcohol Vapor: Measurement and Implications

Decades of alcohol research have established the health risks and pharmacodynamic profile of oral alcohol consumption. Despite isolated periods of public health concern, comparatively less research has evaluated exposure to alcohol vapor. Inhaled alcohol initially bypasses first-pass metabolism and rapidly reaches the arterial circulation and the brain, suggesting that this route of administration may be associated with pharmacological effects that increase the risk of addiction. However, detailed reviews assessing the possible effects of inhaled alcohol in humans are lacking. A comprehensive, systematic literature review was conducted using Google Scholar and PubMed to examine manuscripts studying exposure to inhaled alcohol and measurement of biomarkers (biochemical or functional) associated with alcohol consumption in human participants. Twenty-one publications reported on alcohol inhalation. Fourteen studies examined inhalation of alcohol vapor associated with occupational exposure (e.g., hand sanitizer) in a variety of settings (e.g., naturalistic, laboratory). Six publications measured inhalation of alcohol in a controlled laboratory chamber, and 1 evaluated direct inhalation of an e-cigarette with ethanol-containing "e-liquid." Some studies have reported that inhalation of alcohol vapor results in measurable biomarkers of acute alcohol exposure, most notably ethyl glucuronide. Despite the lack of significantly elevated blood alcohol concentrations, the behavioral consequences and subjective effects associated with repeated use of devices capable of delivering alcohol vapor are yet to be determined. No studies have focused on vulnerable populations, such as adolescents or individuals with alcohol use disorder, who may be most at risk of problems associated with alcohol inhalation.

Oral Human Abuse Potential of Oxycodone DETERx® (Xtampza® ER)

Oxycodone DETERx^® (Collegium Pharmaceutical Inc, Canton, Massachusetts) is an extended‐release, microsphere‐in‐capsule, abuse‐deterrent formulation designed to retain its extended‐release properties after tampering (eg, chewing/crushing). This randomized, double‐blind, placebo‐controlled, triple‐dummy study evaluated the oral abuse potential of intact and chewed oxycodone DETERx capsules compared with crushed immediate‐release oxycodone. Subjects with a history of recreational opioid use who were nondependent/nontolerant to opioids were enrolled. Treatments included intact oxycodone DETERx (high‐fat, high‐calorie meal and fasted), chewed oxycodone DETERx (high‐fat, high‐calorie meal and fasted), crushed immediate‐release oxycodone (fasted), and placebo (high‐fat, high‐calorie meal). Plasma samples were collected to determine pharmacokinetic parameters. The primary endpoint was drug liking at the moment; other endpoints included drug effects questionnaire scores, Addiction Research Center Inventory/Morphine Benzedrine Group score, pupillometry measurements, and safety. Thirty‐eight subjects completed the study. Chewed and intact oxycodone DETERx were bioequivalent, unlike crushed immediate‐release oxycodone, which yielded higher peak oxycodone plasma concentrations compared with all methods of oxycodone DETERx administration. The mean maximum (peak) effect (E_max) for drug liking was significantly lower for chewed and intact oxycodone DETERx than for crushed immediate‐release oxycodone (P < .01). The time to E_max was significantly longer for chewed and intact oxycodone DETERx than for crushed immediate‐release oxycodone (P < .0001). Scores for feeling high and Addiction Research Center Inventory/Morphine Benzedrine Group scores demonstrated lower abuse potential for chewed and intact oxycodone DETERx compared with crushed immediate‐release oxycodone. Study treatments were well tolerated; no subjects experienced serious adverse events. These results demonstrate the lower oral abuse potential of chewed and intact oxycodone DETERx than crushed immediate‐release oxycodone.

The effect of an abuse-deterrent opioid formulation (OxyContin) on opioid abuse-related outcomes in the postmarketing setting

An extended‐release opioid analgesic (OxyContin, OC) was reformulated with abuse‐deterrent properties to deter abuse. This report examines changes in abuse through oral and nonoral routes, doctor‐shopping, and fatalities in 10 studies 3.5 years after reformulation. Changes in OC abuse from 1 year before to 3 years after OC reformulation were calculated, adjusted for prescription changes. Abuse of OC decreased 48% in national poison center surveillance systems, decreased 32% in a national drug treatment system, and decreased 27% among individuals prescribed OC in claims databases. Doctor‐shopping for OC decreased 50%. Overdose fatalities reported to the manufacturer decreased 65%. Abuse of other opioids without abuse‐deterrent properties decreased 2 years later than OC and with less magnitude, suggesting OC decreases were not due to broader opioid interventions. Consistent with the formulation, decreases were larger for nonoral than oral abuse. Abuse‐deterrent opioids may mitigate abuse and overdose risks among chronic pain patients.

A Randomized, Double-Blind, Double-Dummy Study to Evaluate the Intranasal Human Abuse Potential and Pharmacokinetics of a Novel Extended-Release Abuse-Deterrent Formulation of Oxycodone

OBJECTIVE

Evaluate the human abuse potential (HAP) of an experimental, microsphere-in-capsule formulation of extended-release oxycodone (oxycodone DETERx®) (herein "DETERx").

DESIGN

Randomized, double-blind, double-dummy, positive- and placebo-controlled, single-dose, four-phase, four-treatment, crossover study.

SETTING

Clinical research site.

SUBJECTS

There were 39 qualifying subjects (72% male, 85% white, mean age of 27 years) with 36 completing all four Double-blind Treatment Periods.

METHODS

The four phases encompassed: 1) Screening; 2) Drug Discrimination; 3) Double-blind Treatment; and 4) Follow-up. Drug Discrimination tests ensured that subjects could distinguish placebo from opioid. The four Double-blind Treatments compared DETERx-administered as either a crushed intranasal (IN) or an intact oral (PO) preparation-with immediate-release oxycodone IN (OXY-IR IN) and with an intact IN and PO placebo DETERx control.

RESULTS

For primary pharmacokinetic (PK) assessments, abuse quotient (Cmax/Tmax) was lower with DETERx IN than DETERx PO; both treatments were substantially lower than OXY-IR IN (6.24, 8.60, and 69.6 ng/mL/h, respectively). For drug liking, the primary subjective pharmacodynamic (PD) endpoint, both DETERx IN and DETERx PO produced significantly lower scores than OXY-IR IN (P ≤ 0.0001 for each); DETERx IN was less liked than DETERx PO (P ≤ 0.05), mirroring the PK relationships. Objectively assessed pupillometry corroborated the more rapid and significantly greater effect of OXY-IR IN than either DETERx IN or DETERx PO (P ≤ 0.007 for each). Overall safety profiles of DETERx and OXY-IR were comparable and both were well tolerated.

CONCLUSIONS

Pharmacokinetic and pharmacodynamic outcomes suggest that DETERx IN has relatively low HAP; continued research in larger populations is suggested.

Intranasal buprenorphine alone and in combination with naloxone: Abuse liability and reinforcing efficacy in physically dependent opioid abusers

BACKGROUND

Buprenorphine can be abused by the intranasal route. This study sought to examine the relative abuse liability and reinforcing efficacy of intranasal buprenorphine compared to intranasal buprenorphine/naloxone in opioid-dependent individuals.

METHODS

Eleven healthy male and female volunteers physically dependent on short-acting opioids resided as inpatients during participation in this double blind, within subject, placebo-controlled study. Participants were maintained on oxycodone (30 mg/q.i.d., p.o.) throughout the 6-week study. Eight pairs of experimental sessions were conducted at ≥48 h intervals to examine the pharmacodynamic profile (Sample) and reinforcing efficacy (Self-administration the following day) of intranasal placebo, oxycodone (60 mg), buprenorphine (2, 8 & 16 mg) and buprenorphine/naloxone (2/0.5, 8/2 & 16/4 mg). Subjective, observer-rated and physiological measures were collected to assess the magnitude of opioid agonist and antagonist effects. A progressive ratio self-administration procedure assessed choices for drug versus money.

RESULTS

All active doses produced opioid agonist-like effects (e.g., increased ratings of "liking," and miosis) compared to placebo. The effects of buprenorphine and buprenorphine/naloxone were not reliably dose-dependent. Intranasal buprenorphine/naloxone elicited modest and transient opioid withdrawal-like effects in the first hour post-drug administration, while simultaneously blunting or blocking the early onset of agonist effects seen with buprenorphine alone. All active doses of buprenorphine were self-administered more than placebo, but buprenorphine/naloxone doses were not.

CONCLUSIONS

These data confirm that intranasal buprenorphine/naloxone has deterrent properties related to transient withdrawal effects that likely decrease its desirability for misuse compared to buprenorphine in opioid-dependent individuals maintained on short-acting opioids.

Intranasal Abuse Potential, Pharmacokinetics, and Safety of Once-Daily, Single-Entity, Extended-Release Hydrocodone (HYD) in Recreational Opioid Users

Objectives. A once-daily, extended-release hydrocodone bitartrate tablet with abuse-deterrent properties (Hysingla ER® [HYD]) is available for the treatment of chronic pain in appropriate patients. This study evaluated the intranasal abuse potential and pharmacokinetics of HYD coarse and fine particles vs hydrocodone powder or placebo.

Design. Single-center, double-blind, positive- and placebo-controlled, randomized, four-treatment crossover study.

Subjects. Healthy adult, nondependent, recreational opioid users with a history of intranasal abuse.

Methods. During four treatment periods, subjects (N = 31) received hydrocodone powder 60 mg, HYD coarse particles 60 mg, HYD fine particles 60 mg, or placebo, with five-to-seven-day washouts between treatments. Measures over 36 hours postdose included drug-liking and willingness to take drug again, assessed using visual analog scales (VASs), pupillometry, intranasal irritation, and pharmacokinetics.

Results. Insufflation of both HYD coarse and fine particles led to lower “At this Moment” Drug Liking VAS peak values compared with hydrocodone powder, but higher values compared with placebo (P < 0.001 for all comparisons). Similar results were observed for Overall Drug Liking VAS, Take Drug Again VAS, and Subjective Drug Value. Compared with hydrocodone, insufflation of HYD particles led to reduced miosis and increased nasal irritation. Mean hydrocodone C_max following insufflation of HYD coarse particles, HYD fine particles, and hydrocodone powder was 27.5, 36.5, and 105.8 ng/mL, respectively; median T_max was ≥2-fold longer with either HYD particle size than hydrocodone powder; and (C_max/T_max) was 9.5, 13.4, and 82.0 ng/mL/h, respectively. Safety was consistent with that of opioid agonists.

Conclusions. HYD demonstrated reduced intranasal abuse potential compared with hydrocodone powder.

Altered methamphetamine place conditioning in mice vaccinated with a succinyl-methamphetamine-tetanus-toxoid vaccine

BACKGROUND AND OBJECTIVES

We previously reported that an anti-methamphetamine (MA) vaccine attenuated drug-conditioned effects in mice, but it used a carrier protein and adjuvant not available for clinical use. Here we produced a vaccine with the same hapten (succinyl-methamphetamine, SMA) but attached to tetanus toxoid (SMA-TT) and adsorbed to aluminum hydroxide, components approved for use in humans. We then assessed the vaccine's ability to generate anti-MA antibodies, alter acquisition and reinstatement of MA place conditioning, and prevent MA brain penetration.

METHODS

Mice were administered SMA-TT at weeks 0 and 3 and non-vaccinated mice received saline. Anti-MA antibody concentrations were determined at 8 and 12 weeks. Place conditioning began during week 9 in which vaccinated and non-vaccinated mice were divided into groups and conditioned with .5, or 2.0 mg/kg MA. Following acquisition training, mice were extinguished and then a reinstatement test was performed in which mice were administered their original training dose of MA. Separate groups of non-vaccinated and vaccinated mice were administered .5 and 2.0 mg/kg MA and brain MA levels determined.

RESULTS AND CONCLUSIONS

Anti-MA antibody levels were elevated at week 8 and remained so through week 12. The SMA-TT vaccine attenuated acquisition and reinstatement of MA place conditioning. Significantly greater proportions of vaccinated mice during acquisition and reinstatement tests showed conditioned place aversion. Moreover, MA brain levels were decreased in vaccinated mice following administration of both doses of MA.

SCIENTIFIC SIGNIFICANCE

Results support further development of anti-MA vaccines using components approved for use in humans.

E-cigarettes--prevention, pulmonary health, and addiction

BACKGROUND

E-cigarettes are coming into wider use. They are advertised as an aid to smoking cessation, but there is concern that they may also serve as a gateway drug for cigarette smoking.

METHOD

The authors systematically searched the PubMed database for relevant publications on the mechanism of action of e-cigarettes, the nature of their emissions, their assessment by potential users, their efficacy in smoking cessation, and their potential for addiction.

RESULTS

There have been many reports of epidemiologically uninformative case series in which smokers were helped to stop smoking by the use of e- cigarettes. Only two controlled trials have shown that e-cigarettes have approximately the same effect as nicotine substitution therapy when used as an aid to smoking cessation. The effect is nearly independent of nicotine content. E-cigarettes are also consumed, to a small extent, by nonsmokers. As far as can be estimated toxicologically at present, the danger to active and passive smokers of e-cigarettes is presumably orders of magnitude less than that of tobacco smokers, although the variable composition of the fluids used in e-cigarettes introduces a degree of uncertainty.

CONCLUSION

Preclinical and initial clinical data, including some data from randomized controlled trials, indicate that e-cigarettes may be useful as an aid to smoking cessation or as a means of lowering risk in high-risk groups. In contrast to the demonstrated efficacy of multimodal smoking-cessation programs with pharmacological and psychotherapeutic support, the efficacy of e-cigarettes in smoking cessation has not yet been satisfactorily shown. Valid and informative clinical trials are urgently needed. These should also be designed to determine what predisposition(s), if any, might make the use of e-cigarettes more or less successful than that of other aids to smoking cessation. Moreover, e-cigarettes might be a gateway drug for cigarette smoking; thus, no clear recommendation about their use can be made at present.

Inhaled vs. oral alprazolam: subjective, behavioral and cognitive effects, and modestly increased abuse potential

RATIONALE

Infrahuman and human studies suggest that a determinant of the abuse potential of a drug is rate of onset of subjective effects.

OBJECTIVES

This study sought to determine if the rate of onset of subjective effects and abuse potential of alprazolam would be increased when administered via inhalation vs. the oral route.

METHODS

Placebo, inhaled alprazolam (0.5, 1, and 2 mg), and oral alprazolam (1, 2, and 4 mg) were administered under double-blind, double-dummy conditions using a crossover design in 14 healthy participants with histories of drug abuse. Participant and observer ratings and behavioral and cognitive performance measures were assessed repeatedly during 9-h sessions.

RESULTS

Both routes of administration produced orderly dose and time-related effects, with higher doses producing greater and longer-lasting effects. Onset of subjective effects following inhaled alprazolam was very rapid (e.g., 2 vs. 49 min after 2 mg inhaled vs. oral). On measures of abuse potential (e.g., liking and good effects), inhaled alprazolam was more potent, as evidenced by a leftward shift in the dose-response curve. Despite the potency difference, at the highest doses, peak ratings of subjective effects related to abuse potential (e.g., "drug liking") were similar across the two routes. On other measures (e.g., sedation and performance), the routes were equipotent.

CONCLUSIONS

The inhaled route of administration modestly increased the abuse potential of alprazolam despite significantly increasing its rate of onset. If marketed, the reduced availability and increased cost of inhaled alprazolam may render the societal risk of increased abuse to be low.

Comparison of subjective effects of extended-release versus immediate-release oxycodone/acetaminophen tablets in healthy nondependent recreational users of prescription opioids: a randomized trial

BACKGROUND

Prescription opioids have substantial abuse potential. This study compared the positive subjective drug effects of a newly developed extended-release (ER) oxycodone (OC)/acetaminophen (acetyl-para-aminophenol [APAP]) formulation with those of immediate-release (IR) OC/APAP.

METHODS

This randomized, double-blind, active- and placebo-controlled, 7-way crossover study enrolled healthy volunteers who were recreational prescription opioid users. The protocol was approved by an institutional review board and all participants provided written informed consent. Participants received single doses of intact ER and IR OC/APAP 15/650 mg, intact ER and IR OC/APAP 30/1300 mg, crushed ER and IR OC/APAP 30/1300 mg, and placebo. Peak subjective effects (Emax), time to Emax, and area under the drug-effect curves for drug liking, drug high, and good drug effects were measured using visual analogue scales. Least squares means with 95% confidence interval were compared using analysis of variance.

RESULTS

Among completers (N = 55), intact ER OC/APAP produced delayed and lower peak effects versus IR OC/APAP. Comparing intact tablets, the drug liking Emax (least squares means [95% confidence interval]) was significantly lower for OC/APAP 30/1300 mg (76.4 [72.8 to 80.0]) than for IR OC/APAP 30/1300 mg (85.6 [81.9 to 89.2]; difference, -9.2 [-13.1 to -5.2]; P < 0.001). Similar results were observed for intact ER and IR OC/APAP (15 mg/650 mg). Crushing ER OC/APAP 30/1300 mg further delayed these effects compared with the same dose of crushed IR OC/APAP and intact ER OC/APAP.

CONCLUSIONS

Extended-release OC/APAP produced lower subjective drug effects than IR OC/APAP. Crushing ER OC/APAP further delayed onset of subjective effects compared with intact ER OC/APAP. The ER OC/APAP may be less attractive for abuse than IR OC/APAP.

CLINICAL TRIAL REGISTRATION

This phase 1 study conducted in the United States was not registered.

Attenuation of cocaine-induced locomotor activity in male and female mice by active immunization

BACKGROUND AND OBJECTIVES

Immunotherapy for drug addiction is being investigated in several laboratories but most studies are conducted in animals of one sex. Yet, women show heightened immune responses and are more likely to develop autoimmune diseases than men. The purpose of this study was to compare the effects of an active anti-cocaine vaccine, succinyl-norcocaine conjugated to keyhole limpet hemocyanin, for its ability to elicit antibodies and alter cocaine-induced ambulatory activity in male versus female mice.

METHODS

Male and female BALB/c mice were vaccinated (n = 44) or served as non-vaccinated controls (n = 34). Three weeks after initial vaccination, a booster was given. Ambulatory activity induced by cocaine (20 mg/kg) was assessed at 7 weeks and plasma obtained at 8 weeks to assess antibody levels.

RESULTS

High antibody titers were produced in mice of both sexes. The vaccine reduced ambulatory activity cocaine-induced but this effect was greater in female compared to male mice.

DISCUSSION AND CONCLUSIONS

The efficacy of this anti-cocaine vaccine is demonstrated in mice of both sexes but its functional consequences are greater in females than males.

SCIENTIFIC SIGNIFICANCE

Results point to the importance of testing animals of both sexes in studies of immunotherapies for addiction.

Familial aggregation of tobacco use behaviors among Amish men

INTRODUCTION

Tobacco use is a complex behavior. The Old Order Amish community offers unique advantages for the study of tobacco use because of homogenous ancestral background, sociocultural similarity, sex-specific social norms regarding tobacco use, and large family size. Tobacco use in the Old Order Amish community is almost exclusively confined to males.

METHODS

We examined characteristics of tobacco use and familial aggregation among 1,216 Amish males from cross-sectional prospectively collected data. Outcomes examined included ever using tobacco regularly, current use, quantity of use, duration of use, and frequency of use.

RESULTS

Sixteen percent of Amish men were current tobacco users, with the majority reporting cigar use only. Higher rates of tobacco use were found among sons of fathers who smoked compared with sons of fathers who did not smoke (46% vs. 22%, p < .001) as well as among brothers of index cases who smoked compared with brothers of index cases who did not smoke (61% vs. 29%, p < .001). After controlling for shared household effects and age, heritability accounted for 66% of the variance in ever smoking regularly (p = .045).

CONCLUSIONS

The familial patterns of tobacco use observed among Amish men highlight the important role of family in propagating tobacco use and support the usefulness of this population for future genetic studies of nicotine addiction.

Nicotine Absorption from Smokeless Tobacco Modified to Adjust pH

INTRODUCTION

Nicotine delivery from smokeless tobacco (ST) products leads to addiction and the use of ST causes pathology that is associated with increased initiation of cigarette smoking. The rapid delivery of nicotine from ST seems to be associated with the pH of the aqueous suspension of the products - high pH is associated with high nicotine absorption. However, early studies compared nicotine absorption from different commercial products that not only differed in pH but in flavoring, nicotine content, and in format-pouches and loose tobacco.

METHODS

The present study compared nicotine absorption from a single unflavored referent ST product (pH 7.7) that was flavored with a low level of wintergreen (2 mg/g) and the pH was amended to either high (8.3) or low (5.4) pH with sodium carbonate or citric acid, respectively.

RESULTS

In a within-subject clinical study, the higher pH products delivered more nicotine. No significant differences were seen between perceived product strengths and product experience in all conditions. Heart rate increased by 4 to 6 beats per minute after the high pH flavored and the un-amended product but did not change after the low pH flavored product.

CONCLUSIONS

These results indicate that pH is a primary determinant of buccal nicotine absorption. The role of flavoring and other components of ST products in nicotine absorption remain to be determined.

Genetic and pharmacokinetic determinants of response to transdermal nicotine in white, black, and Asian nonsmokers

The aim of the study was to examine genetic, pharmacokinetic and demographic factors that influence sensitivity to nicotine in never smokers. Sixty never smokers, balanced for gender and race (Caucasian, Blacks and Asian), wore 7 mg nicotine skin patches for up to 8 hours. Serial plasma nicotine concentrations and subjective and cardiovascular effects were measured, and genetic variation in the CYP2A6 gene, the primary enzyme responsible for nicotine metabolism, was assessed. Nicotine toxicity requiring patch removal developed in 9 subjects and was strongly associated with rate of rise and peak concentrations of plasma nicotine. Toxicity, subjective and cardiovascular effects of nicotine were associated with the presence of reduced function CYP2A6 alleles, presumably reflecting slow nicotine metabolic inactivation. This study has implications for understanding individual differences in responses to nicotine medications, particularly when the latter are used for treating medical conditions in non-smokers, and possibly in vulnerability to developing nicotine dependence.

A morphine conjugate vaccine attenuates the behavioral effects of morphine in rats

Vaccines for opioid dependence may provide a treatment that would reduce or slow the distribution of the drug to brain, thus reducing the drug's reinforcing effects. We tested whether a conjugate vaccine against morphine (keyhole limpet hemocyanin-6-succinylmorphine; KLH-6-SM) administered to rats would produce antibodies and show specificity for morphine or other heroin metabolites. The functional effects of the vaccine were tested with antinociceptive and conditioned place preference (CPP) tests. Rats were either vaccinated with KLH-6-SM and received two boosts 3 and 16 weeks later or served as controls and received KLH alone. Anti-morphine antibodies were produced in vaccinated rats; levels increased and were sustained at moderate levels through 24 weeks. Antibody binding was inhibited by free morphine and other heroin metabolites as demonstrated by competitive inhibition ELISA. Vaccinated rats showed reduced morphine CPP, tested during weeks 4 to 6, and decreased antinociceptive responses to morphine, tested at week 7. Brain morphine levels, assessed using gas-chromatography coupled to mass spectrometry (GC-MS) on samples obtained at 26 weeks, were significantly lower in vaccinated rats. This suggests that morphine entry into the brain was reduced or slowed. These results provide support for KLH-6-SM as a candidate vaccine for opioid dependence.

Nicotine levels after IV nicotine and cigarette smoking in men

There has been considerable interest in the pharmacodynamics and pharmacokinetics of nicotine and the influence of different routes of administration. However, these variables are often examined in separate studies, and there is less information about the temporal relation between subjective reports and plasma nicotine levels. This study examined the time course and magnitude of plasma nicotine levels and reports of subjective "high" in nicotine-dependent men after 12 or more hrs of abstinence. The effects of two doses of IV nicotine and two doses of nicotine from cigarette smoking were compared, and samples were collected at 2-min intervals. Plasma nicotine levels after smoking a high-nicotine cigarette were significantly greater than after either dose of IV nicotine (p < .001). However, Visual Analog Scale (VAS) ratings of "high" after both doses of IV nicotine and smoking a high-nicotine cigarette did not differ significantly, and followed a similar time course. After smoking a low-nicotine cigarette, VAS ratings of "high" were significantly lower than after either IV nicotine dose or smoking a high-nicotine cigarette (p < .001). Peak levels of "high" were reported within 2 min after IV nicotine administration and the onset of cigarette smoking. Then "high" ratings abruptly decreased, while plasma nicotine rose to peak levels within 4 to 6 min after IV nicotine and 12 to 14 min during cigarette smoking. Plasma nicotine levels did not appear to determine the magnitude or time course of subjective effects under these conditions.

Can you vaccinate against substance abuse?

Vaccines are being developed against substance abuse and most progress has been made with anti-cocaine, nicotine and opiate vaccines, but new ones are being developed for methamphetamine and may be in humans within 18 - 24 months. These haptenated vaccines share a common problem in that only about one-third of those vaccinated get a sufficiently robust antibody titer to enable them to effectively block drug use. This problem is being addressed with better carrier proteins and new adjuvants beyond alum. This review provides details about these developing vaccines that act through pharmacokinetic rather than pharmacodynamics blockade. Due to this pharmacokinetic mechanism of keeping abused drugs in the bloodstream and not allowing them entry into the brain or other organs, these vaccines have very few side effects compared to other blockers used in addictions treatment.

Nicotine related brain activity: the influence of smoking history and blood nicotine levels, an exploratory study

OBJECTIVE

In this study, we sought to explore brain activity in nicotine-dependent men in response to acute intravenous nicotine using pharmacological magnetic resonance imaging (phMRI).

METHODS

phMRI was used to evaluate brain activity in response to 1.5 mg/70 kg intravenous nicotine or saline. The nicotine and saline were administered on different visits. The time courses of individual subjects' nicotine levels were used as regressors to assess neural activity relating to the infusions. The influence of smoking history and physiological measures on the response to nicotine were also investigated.

RESULTS

Greater lifetime exposure to cigarette smoking was significantly correlated with higher peak serum nicotine levels. PhMRI analysis of the differential response of nicotine compared to the saline condition showed distinctive activation patterns when analyzed with the (a) nicotine time course, (b) nicotine time course controlling for smoking history (pack years), and (c) pack years controlling for nicotine.

CONCLUSIONS

These results suggest that smoking exposure history influences serum nicotine levels and the brain's response to nicotine. Alterations in brain activity may be a result of vascular and neuro-adaptations involved in drug exposure and addiction.

Assessment of a formulation designed to be crush-resistant in prescription opioid abusers

BACKGROUND

The extent of prescription opioid abuse has led to the development of formulations that are difficult to crush. The purpose of the present studies was to examine whether experienced prescription opioid abusers (individuals using prescription opioids for non-medical purposes regardless of how they were obtained) were able to prepare a formulation of oxymorphone hydrochloride ER 40 mg designed to be crush-resistant (DCR) for intranasal (study 1) or intravenous abuse (study 2), utilizing a non-crush-resistant formulation of oxymorphone (40 mg; OXM) as a positive control.

METHODS

No drug was administered in these studies. Participants were provided with DCR and OXM tablets in random order and asked to prepare them for abuse with tools/solutions that they had previously requested. The primary outcome for study 1 was particle size distribution, and the primary outcome for study 2 was percent yield of active drug in the extracts. Other descriptive variables were examined to better understand potential responses to these formulations.

RESULTS

Fewer DCR than OXM particles were smaller than 1.705 mm (9.8% vs. 97.7%), and thus appropriate for analyses. Percent yield of active drug in extract was low and did not differ between the two formulations (DCR: 1.95%; OXM: 1.29%). Most participants were not willing to snort (92%) or inject (84%) the tampered products. Participants indicated that they found less relative value in the DCR than the OXM formulation across both studies.

CONCLUSIONS

These data suggest that the oxymorphone DCR formulations may be a promising technology for reducing opioid abuse.

Importance of pharmacokinetic profile and timing of coadministration of short- and long-acting formulations of methylphenidate on patterns of subjective responses and abuse potential

OBJECTIVE

Subjective responses (ie, liking, disliking) to stimulants are thought to be proxies for abuse potential. Greater subjective responses have been documented in formulations that are more rapidly absorbed. However, repeat dosing has not been examined.

METHODS

Subjective responses on the Drug Rating Questionnaire were compared in 26 healthy adults after administration of short- (immediate-release [IR] methylphenidate [MPH]) and long- (osmotically controlled-release oral delivery system [OROS] MPH) acting stimulant formulations. The second dose was administered 4 hours after initial dosing. All subjects received all 5 conditions (ie, placebo to placebo; IR-MPH to IR-MPH; IR-MPH to OROS-MPH; OROS-MPH to IR-MPH; or OROS-MPH to OROS-MPH) in a double-blind, counter-balanced design on 5 separate days.

RESULTS

Plasma levels and subjective patterns of detection were higher when an IR formulation was administered during the ascending phase of a first-administered long-acting dose (OROS).

CONCLUSION

These results emphasize the critical role that formulation type (IR vs OROS) and timing of administration (ascending vs descending phase) play when short- and long-acting formulations are coadministered. Such knowledge provides important information for clinicians about the safety and tolerability of the timing of repeat dosing of various permutations of coadministration of MPH formulations.

A systematic review of nicotine by inhalation: is there a role for the inhaled route?

INTRODUCTION

A considerable minority of adults remain addicted to smoking cigarettes despite substantial education and public health efforts. Nicotine replacement therapies have only modest long-term quit rates. The pulmonary route of nicotine delivery has advantages over other routes. However, there are regulatory and technical barriers to the development of pulmonary nicotine delivery devices, and hence, none are commercially available. Current knowledge about pulmonary nicotine delivery is scattered throughout the literature and other sources such as patent applications. This review draws together what is currently known about pulmonary nicotine delivery and identifies potential ways that deep lung delivery can be achieved with a simple portable device.

AIMS

To systematically review clinical trials of nicotine inhalers, determine whether they delivered nicotine via the lung, and identify ways that pulmonary delivery of medicinal nicotine might be achieved and the technical issues involved.

METHODS

Systematic search of Medline and Embase.

RESULTS

Thirty-eight trials met the inclusion criteria. Cough, reflex interruption of smooth inspiration, and throat scratch limited the usefulness of nicotine inhalers. The pharmacokinetic profiles of portable nicotine inhalers were inferior to smoking, but among commercially available products, electronic cigarettes are currently the most promising.

CONCLUSIONS

Pulmonary nicotine delivery might be maximized by use of nicotine salts, which have a more physiological pH than pure nicotine, by ensuring the mass of the particles is optimal for alveolar absorption, and by adding flavoring agents. Metered-dose inhalers potentially can deliver nicotine more efficiently than other nicotine products, facilitating smoking cessation and improving smokers' lives.