Measuring Attractiveness for Abuse of Prescription Opioids

Suvorexant, an FDA-approved dual orexin receptor antagonist, reduces oxycodone self-administration and conditioned reinstatement in male and female rats

Background: The Department of Health and Human Services reports that prescription pain reliever (e.g., oxycodone) misuse was initiated by 4,400 Americans each day in 2019. Amid the opioid crisis, effective strategies to prevent and treat prescription opioid use disorder (OUD) are pressing. In preclinical models, the orexin system is recruited by drugs of abuse, and blockade of orexin receptors (OX receptors) prevents drug-seeking behavior. The present study sought to determine whether repurposing suvorexant (SUV), a dual OX receptor antagonist marketed for the treatment of insomnia, can treat two features of prescription OUD: exaggerated consumption and relapse. Methods: Male and female Wistar rats were trained to self-administer oxycodone (0.15 mg/kg, i. v., 8 h/day) in the presence of a contextual/discriminative stimulus (S^D) and the ability of SUV (0-20 mg/kg, p. o.) to decrease oxycodone self-administration was tested. After self-administration testing, the rats underwent extinction training, after which we tested the ability of SUV (0 and 20 mg/kg, p. o.) to prevent reinstatement of oxycodone seeking elicited by the S^D. Results: The rats acquired oxycodone self-administration and intake was correlated with the signs of physical opioid withdrawal. Additionally, females self-administered approximately twice as much oxycodone as males. Although SUV had no overall effect on oxycodone self-administration, scrutiny of the 8-h time-course revealed that 20 mg/kg SUV decreased oxycodone self-administration during the first hour in males and females. The oxycodone S^D elicited strong reinstatement of oxycodone-seeking behavior that was significantly more robust in females. Suvorexant blocked oxycodone seeking in males and reduced it in females. Conclusions: These results support the targeting of OX receptors for the treatment for prescription OUD and repurposing SUV as pharmacotherapy for OUD.

Comparing the feasibility of four web-based recruitment strategies to evaluate the treatment preferences of rural and urban adults who misuse non-prescribed opioids

This cross-sectional study examined the feasibility of using four different web-based strategies to recruit rural and urban adults who use opioids non-medically for a survey on opioid use disorder (OUD) treatment preferences, and compared the treatment preferences of rural versus urban participants. Preferences for medication for opioid use disorder (MOUD) formulation and OUD treatment models were assessed through an online survey. Recruitment advertisements were shown on Facebook, Google AdWords, Reddit, and Amazon Mechanical Turk (MTurk). Participants were categorized by zip code into urban versus rural residence using the Centers for Medicaid and Medicaid Health Resources and Services Administration definitions. OUD treatment preferences were compared using chi-square and t-tests. Among the 851 participants recruited, 815 provided zip codes and were classified as residing in rural (n = 200, 24.5%) or urban (n = 615, 75.4%) regions. A crowdsourcing service (MTurk) recruited the most rural participants, while posts on a social news website (Reddit) recruited the most urban participants (χ²₃ = 17.0, p < 0.01). While preferred MOUD formulation and OUD treatment model did not differ by rurality, rural participants were more likely to report a willingness to receive OUD treatment integrated with general medical care (χ²₁ = 18.9, p < 0.0001). This study demonstrated that web-based strategies are feasible for recruiting rural adults who misuse opioids. Results suggest OUD treatment preferences largely did not differ by rural residence, and highlight the importance of enhancing the availability and increasing education about MOUD formulations in rural regions.

Oxycodone in the Opioid Epidemic: High 'Liking', 'Wanting', and Abuse Liability

It is estimated that nearly a third of people who abuse drugs started with prescription opioid medicines. Approximately, 11.5 million Americans used prescription drugs recreationally in 2016, and in 2018, 46,802 Americans died as the result of an opioid overdose, including prescription opioids, heroin, and illicitly manufactured fentanyl (National Institutes on Drug Abuse (2020) Opioid Overdose Crisis. https://www.drugabuse.gov/drugs-abuse/opioids/opioid-overdose-crisis . Accessed 06 June 2020). Yet physicians will continue to prescribe oral opioids for moderate-to-severe pain in the absence of alternative therapeutics, underscoring the importance in understanding how drug choice can influence detrimental outcomes. One of the opioid prescription medications that led to this crisis is oxycodone, where misuse of this drug has been rampant. Being one of the most highly prescribed opioid medications for treating moderate-to-severe pain as reflected in the skyrocketed increase in retail sales of 866% between 1997 and 2007, oxycodone was initially suggested to be less addictive than morphine. The false-claimed non-addictive formulation of oxycodone, OxyContin, further contributed to the opioid crisis. Abuse was often carried out by crushing the pills for immediate burst release, typically by nasal insufflation, or by liquefying the pills for intravenous injection. Here, we review oxycodone pharmacology and abuse liability as well as present the hypothesis that oxycodone may exhibit a unique pharmacology that contributes to its high likability and abuse susceptibility. We will discuss various mechanisms that likely contribute to the high abuse rate of oxycodone including clinical drug likability, pharmacokinetics, pharmacodynamics, differences in its actions within mesolimbic reward circuity compared to other opioids, and the possibility of differential molecular and cellular receptor interactions that contribute to its selective effects. We will also discuss marketing strategies and drug difference that likely contributes to the oxycodone opioid use disorders and addiction.

How Motivations for Using Buprenorphine Products Differ From Using Opioid Analgesics: Evidence from an Observational Study of Internet Discussions Among Recreational Users

BACKGROUND

Opioid use disorder (OUD) poses medical and societal concerns. Although most individuals with OUD in the United States are not in drug abuse treatment, buprenorphine is considered a safe and effective OUD treatment, which reduces illicit opioid use, mortality, and other drug-related harms. However, as buprenorphine prescriptions increase, so does evidence of misused, abused, or diverted buprenorphine. Users' motivations for extratreatment use of buprenorphine (ie, misuse or abuse of one's own prescription or use of diverted medication) may be different from the motivations involved in analgesic opioid products. Previous research is based on small sample sizes and use surveys, and none directly compare the motivations for using buprenorphine products (ie, tablet or film) with other opioid products having known abuse potential.

OBJECTIVE

The aim of the study was to describe and compare the motivation-to-use buprenorphine products, including buprenorphine/naloxone (BNX) sublingual film and oxycodone extended-release (ER), as discussed in online forums.

METHODS

Web-based posts from 2012 to 2016 were collected from online forums using the Web Informed Services internet monitoring archive. A random sample of posts was coded for motivation to use. These posts were coded into the following motivation categories: (1) use to avoid withdrawal, (2) pain relief, (3) tapering from other drugs, (4) opioid addiction treatment, (5) recreational use (ie, to get high), and (6) other use. Oxycodone ER, an opioid analgesic with known abuse potential, was selected as a comparator.

RESULTS

Among all posts, 0.81% (30,576/3,788,922) discussed motivation to use one of the target products. The examination of query-selected posts revealed significantly greater discussion of buprenorphine products than oxycodone ER (P<.001). The posts mentioning buprenorphine products were more likely than oxycodone ER to discuss treatment for OUD, tapering down use, and/or withdrawal management (P<.001). Buprenorphine-related posts discussed recreational use (375/1020, 36.76%), although much less often than in oxycodone ER posts (425/508, 83.7%). Despite some differences, the overall pattern of motivation to use was similar for BNX sublingual film and other buprenorphine products.

CONCLUSIONS

An analysis of spontaneous, Web-based discussion among recreational substance users who post on online drug forums supports the contention that motivation-to-use patterns associated with buprenorphine products are different from those reported for oxycodone ER. Although the findings presented here are not expected to reflect the actual use of the target products, they may represent the interests and motivations of those posting on the online forums. Buprenorphine-related posts were more likely to discuss treatment for OUD, tapering, and withdrawal management than oxycodone ER. Although the findings are consistent with a purported link between the limited availability of medication-assisted therapies for substance use disorders and use of diverted buprenorphine products for self-treatment, recreational use was a motivation expressed in more than one-third of buprenorphine posts.

Human Abuse Potential of Oral NKTR-181 in Recreational Opioid Users: A Randomized, Double-Blind, Crossover Study

OBJECTIVE

To evaluate the human abuse potential, pharmacokinetics, pharmacodynamics, and safety of oral NKTR-181 (oxycodegol), a novel full mu-opioid receptor agonist, relative to oral oxycodone.

DESIGN

This double-blind, randomized, single-dose, crossover human abuse potential study was conducted in healthy, adult, non-physically dependent recreational opioid users.

SETTING

Inpatient clinical research site.

SUBJECTS

Seventy-one subjects randomized (95.7% male, 65.2% African American, mean age = 31.7 years).

METHODS

The primary objective was to compare two therapeutic doses of NKTR-181 (400 and 600 mg) with 40 and 60 mg of oxycodone and a supratherapeutic dose (1200 mg) of NKTR-181 with 60 mg of oxycodone using visual analog scale (VAS) ratings for Drug Liking "at this moment" (Drug Liking). Secondary objectives included VAS ratings for other subjective measures, and central nervous system (CNS) mu-opioid effects were assessed using pupillometry. Each subject received single oral doses of five treatments and matching placebo.

RESULTS

Compared with 40 and 60 mg of oxycodone, the maximum mean Drug Liking score at 400 and 600 mg NKTR-181 was significantly lower, and the rate of onset and extent of Drug Liking for all NKTR-181 doses in the first two hours postdose were also significantly lower. Delayed attenuated Drug Liking and pupillary miosis response following administration of NKTR-181 vs oxycodone were consistent with slower NKTR-181 CNS entry kinetics and mu-opioid receptor binding. No adverse events were rated as severe, and somnolence and dizziness occurred more frequently when subjects received oxycodone.

CONCLUSIONS

NKTR-181 at oral doses of 400 and 600 mg showed significantly fewer and less severe subjective effects accepted as representative of opioid abuse potential, such as lower peak Drug Liking in recreational opioid users, than 40 and 60 mg of oxycodone.

Physical Barrier Type Abuse-Deterrent Formulations: Mechanistic Understanding of Sintering-Induced Microstructural Changes in Polyethylene Oxide Placebo Tablets

The main goal of the presented work was to understand changes in the microstructure of tablets, as well as the properties of its main component viz. polyethylene oxide (PEO) as a function of sintering. Key polymer variables and sintering conditions were investigated, and sintering-induced increase in tablet tensile strength was evaluated. For the current study, binary-component placebo tablets comprised of varying ratios of PEO and anhydrous dibasic calcium phosphate (DCP) were prepared at two levels of tablet solid fraction. The prepared tablets were sintered in an oven at 80°C at different time points ranging from 10 to 900 min and were evaluated for pore size, tablet expansion (%), and PEO crystallinity. The results showed that for efficient sintering and a significant increase in the tablet tensile strength, a minimum of 50% w/w PEO was required. Moreover, all microstructural changes in tablets were found to occur within 60 min of sintering, with no significant changes occurring thereafter. Sintering also resulted in a decrease in PEO crystallinity, causing changes in polymer ductility. These changes in PEO ductility resulted in tablets with higher tensile strength. Formulation variables such as PEO level and PEO particle size distribution were found to be important influencers of the sintering process. Additionally, tablets with high initial solid fraction and sintering duration of 60 min were found to be optimal conditions for efficient sintering of PEO-based compacts. Finally, prolonged sintering times were not found to provide any additional benefits in terms of abuse-deterrent properties.

Utilizing social media to explore overdose and HIV/HCV risk behaviors among current opioid misusers

INTRODUCTION

Opioid misuse has evolved into an American health crisis over the past decade, becoming a public health epidemic. Measures need to be taken to prevent overdoses by opioid misuse as well as prevent the transition into injection drug use, a high risk factor for contracting HIV/HCV. This study utilized social media to survey individuals currently misusing opioids to identify groups of individuals with different risk and use patterns.

METHODS

We recruited participants for our online survey from Reddit. Five risk behaviors were used to characterize overdose and HIV/HCV risk groups. Gender, age, and socioeconomic status were also included in the analyses, as well as items outlining social media use surrounding opioids.

RESULTS

Two groups of participants were characterized by high likelihoods of different combinations of risky behaviors: (1) Overdose Risk Group and (2) Sexual Risk Group. Those in the Overdose Risk Group were more likely to be younger in age and female, and this group was more likely to desire or be ready for treatment relative to the lowest risk group. Those in the Sexual Risk Group were more likely to be of a minority race/ethnicity, to desire or be ready for treatment, and to post more often on Reddit about opioid use.

DISCUSSION

The results of this study illustrate patterns of opioid use and risk behaviors to inform tailored outreach and treatment efforts for groups of opioid misusers and suggests the potential for utilizing social media as a tool to engage these individuals into treatment and recovery activities.

Relative Abuse of Crush-Resistant Prescription Opioid Tablets via Alternative Oral Modes of Administration

Objective

Some crush-resistant tablet formulations (CRTs) reduce prescription opioid abuse by nonoral routes of administration (ROAs), especially insufflation and injection, while oral abuse increases. Oral abuse involving product manipulation vs swallowing whole for CRTs and comparators was examined.

Methods

Abuse by oral modes of administration (e.g., swallowing whole, chewing, dissolving in the mouth), was examined using the ASI-MV, a computerized, clinical interview for adults in substance abuse treatment from January 2009 to March 2015. CRTs (reformulated oxycodone extended-release [ER], reformulated oxymorphone ER, and tapentadol ER) were compared with non-CRT versions, morphine ER, and oxycodone immediate-release single entity. Analyses employed descriptive statistics and logistic regression.

Results

Among 364,329 unique assessments, 18,135 patients reported oral abuse of the CRTs and comparators examined. CRTs had a higher prevalence of oral abuse involving product manipulation than comparators (P < 0.0001) among all abusers of product. Oral abuse involving product manipulation for CRTs was greater among the subset of patients reporting oral abuse and significantly higher than comparators (P < 0.003). CRTs were significantly less likely than comparators to be swallowed whole (P < 0.0001) and significantly more likely to be chewed (P < 0.003). CRTs were more likely to be dissolved in the mouth than most comparators.

Conclusions

Results suggest the need for abuse-deterrent formulations designed to reduce abuse by oral administration with product manipulation, such as chewing. Advances in this area may reduce the overall abuse of prescription opioids and interrupt the progression from abuse by swallowing whole to oral administration involving product manipulation and other ROAs.

Recent Perspectives in Hot Melt Extrusion-Based Polymeric Formulations for Drug Delivery: Applications and Innovations

Hot melt extrusion (HME), a technology which mixing the advantages of solid dispersion technology and mechanical preparation, is accepted in varied applications in pharmaceutical formulations. When combined with other techniques, such as nanotechnique, three-dimensional printing, and co-extrusion, HME becomes much more multifunctional in the application of drug delivery. While in most cases, polymers employed in HME are responsible for the final property of products. The process of HME together with the selection of materials employed in HME were described briefly. In addition, the applications of HME in drug delivery and its currently status in the pharmaceutical field were also included. Some commercial products produced by HME have met the approval of FDA, indicating the commercial viability of this technique. Although showing great potential in pharmaceutical manufacturing, HME is still challenged by high temperature, shear force, and high input energy. Development of equipment, modifying the parameters, and optimization of polymeric formulations are needed for a safe, effective, and multifunctional hot melt extrusion drug delivery system. Also, wider range of combinations between HME and other techniques may provide guideline for developing multiple applications in drug delivery.

Using Social Listening Data to Monitor Misuse and Nonmedical Use of Bupropion: A Content Analysis

Background

The nonmedical use of pharmaceutical products has become a significant public health concern. Traditionally, the evaluation of nonmedical use has focused on controlled substances with addiction risk. Currently, there is no effective means of evaluating the nonmedical use of noncontrolled antidepressants.

Objective

Social listening, in the context of public health sometimes called infodemiology or infoveillance, is the process of identifying and assessing what is being said about a company, product, brand, or individual, within forms of electronic interactive media. The objectives of this study were (1) to determine whether content analysis of social listening data could be utilized to identify posts discussing potential misuse or nonmedical use of bupropion and two comparators, amitriptyline and venlafaxine, and (2) to describe and characterize these posts.

Methods

Social listening was performed on all publicly available posts cumulative through July 29, 2015, from two harm-reduction Web forums, Bluelight and Opiophile, which mentioned the study drugs. The acquired data were stripped of personally identifiable identification (PII). A set of generic, brand, and vernacular product names was used to identify product references in posts. Posts were obtained using natural language processing tools to identify vernacular references to drug misuse-related Preferred Terms from the English Medical Dictionary for Regulatory Activities (MedDRA) version 18 terminology. Posts were reviewed manually by coders, who extracted relevant details.

Results

A total of 7756 references to at least one of the study antidepressants were identified within posts gathered for this study. Of these posts, 668 (8.61%, 668/7756) referenced misuse or nonmedical use of the drug, with bupropion accounting for 438 (65.6%, 438/668). Of the 668 posts, nonmedical use was discouraged by 40.6% (178/438), 22% (22/100), and 18.5% (24/130) and encouraged by 12.3% (54/438), 10% (10/100), and 10.8% (14/130) for bupropion, amitriptyline, and venlafaxine, respectively. The most commonly reported desired effects were similar to stimulants with bupropion, sedatives with amitriptyline, and dissociatives with venlafaxine. The nasal route of administration was most frequently reported for bupropion, whereas the oral route was most frequently reported for amitriptyline and venlafaxine. Bupropion and venlafaxine were most commonly procured from health care providers, whereas amitriptyline was most commonly obtained or stolen from a third party. The Fleiss kappa for interrater agreement among 20 items with 7 categorical response options evaluated by all 11 raters was 0.448 (95% CI 0.421-0.457).

Conclusions

Social listening, conducted in collaboration with harm-reduction Web forums, offers a valuable new data source that can be used for monitoring nonmedical use of antidepressants. Additional work on the capabilities of social listening will help further delineate the benefits and limitations of this rapidly evolving data source.

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.

Risk based in vitro performance assessment of extended release abuse deterrent formulations

High strength extended release opioid products, which are indispensable tools in the management of pain, are associated with serious risks of unintentional and potentially fatal overdose, as well as of misuse and abuse that might lead to addiction. The issue of drug abuse becomes increasingly prominent when the dosage forms can be readily manipulated to release a high amount of opioid or to extract the drug in certain products or solvents. One approach to deter opioid drug abuse is by providing novel abuse deterrent formulations (ADF), with properties that may be viewed as barriers to abuse of the product. However, unlike regular extended release formulations, assessment of ADF technologies are challenging, in part due to the great variety of formulation designs available to achieve deterrence of abuse by oral, parenteral, nasal and respiratory routes. With limited prior history or literature information, and lack of compendial standards, evaluation and regulatory approval of these novel drug products become increasingly difficult. The present article describes a risk-based standardized in-vitro approach that can be utilized in general evaluation of abuse deterrent features for all ADF products.

Correlation of Subjective Effects with Systemic Opioid Exposure from Fixed-Dose Combinations of Oxycodone/Acetaminophen in Recreational Users of Prescription Drugs

OBJECTIVE

To correlate abuse-related pharmacodynamic measures and pharmacokinetic measures after administering immediate-release/extended-release and immediate-release oxycodone/acetaminophen fixed-dose combination analgesicsDesign. Randomized, double-blind, active- and placebo-controlled, 7-way crossover studySetting. Contract research organizationSubjects. Nondependent recreational users of prescription opioids.

METHODS

Participants received single doses of intact immediate-release/extended-release and immediate-release oxycodone/acetaminophen 15/650 mg, intact immediate-release/extended-release and immediate-release oxycodone/acetaminophen 30/1,300 mg, crushed immediate-release/extended-release and immediate-release oxycodone/acetaminophen 30/1,300 mg, and placebo. Measures of pharmacodynamics (pupillometry, drug liking, drug high, good drug effects) and pharmacokinetics were assessed predose and up to 24 hours postdose, and correlations between pharmacokinetic parameters and pharmacodynamic data were explored.

RESULTS

Of 61 participants, 55 completed all 7 treatments. Intact immediate-release/extended-release oxycodone/acetaminophen produced 50% lower oxycodone peak plasma concentration (C_max) than immediate-release oxycodone/acetaminophen. Median oxycodone time to C_max (t_max) was significantly longer (P<0.001) for intact immediate-release/extended-release oxycodone/acetaminophen than immediate-release oxycodone/acetaminophen. The pharmacokinetics of crushed immediate-release/extended-release and immediate-release oxycodone/acetaminophen (30/1,300 mg) followed a similar pattern. Crushing did not shorten the median oxycodone t_max for immediate-release/extended-release oxycodone/acetaminophen (30/1,300 mg). Strong correlations were observed between oxycodone C_max and area under the curve from time 0 to time x peak effects and area under the subjective effect curve from time 0 to time x for all subjective effects (R²=0.711-0.997).

CONCLUSION

Immediate-release/extended-release oxycodone/acetaminophen produced lower oxycodone C_max and longer t_max than immediate-release oxycodone/acetaminophen. Lower oxycodone concentrations, particularly at earlier time points, were strongly correlated with lesser positive subjective drug effects.

Safety and Tolerability of Biphasic Immediate-Release/Extended-Release Oxycodone/Acetaminophen Tablets: Analysis of 11 Clinical Trials

OBJECTIVES

To characterize the safety of immediate-release (IR)/extended-release (ER) oxycodone (OC)/acetaminophen (APAP).

METHODS

Data were assessed from 9 phase 1 trials in healthy volunteers and recreational users of prescription opioids (N = 405), including 5 single-dose and 3 multidose open-label pharmacokinetic studies of IR/ER OC/APAP and active comparators; and 1 randomized, controlled, single-dose human abuse potential (HAP) study comparing IR/ER OC/APAP, IR OC/APAP, and placebo in recreational users of opioids; and 2 phase 3 trials (N = 701) including a 48-hour placebo-controlled safety and efficacy study in patients with moderate to severe postbunionectomy pain with a 14-day open-label safety extension and a long-term (≤ 35 days) open-label safety study in patients with chronic osteoarthritis pain or chronic low back pain.

RESULTS

Adverse events (AEs) experienced by ≥ 10% of participants receiving IR/ER OC/APAP in all trials were pruritus, nausea, vomiting, dizziness, headache, and somnolence; these AEs occurred with similar frequency for equianalgesic doses of IR OC/APAP and IR OC but less frequently for IR tramadol HCl/APAP. In the HAP study, crushing IR/ER or IR OC/APAP tablets did not increase frequency of AEs. Constipation was experienced by < 10% of participants receiving IR/ER OC/APAP. No serious (SAE) or severe AEs were reported in phase 1 trials. In phase 3 trials of 8 reported SAEs, only 1 treatment-related SAE (hypersensitivity to placebo) required treatment discontinuation. No clinically meaningful changes in vital signs, oxygen saturation, electrocardiograms, or laboratory values were reported.

CONCLUSIONS

Safety and tolerability of IR/ER OC/APAP are similar to other low-dose opioid/APAP analgesics.

Methods and predictors of tampering with a tamper-resistant controlled-release oxycodone formulation

BACKGROUND

In April 2014, a tamper-resistant controlled-release oxycodone formulation was introduced into the Australian market. This study aimed to identify the level and methods of tampering with reformulated oxycodone, demographic and clinical characteristics of those who reported tampering with reformulated oxycodone, and perceived attractiveness of original and reformulated oxycodone for misuse (via tampering).

METHODS

A prospective cohort of 522 people who regularly tampered with pharmaceutical opioids and had tampered with the original oxycodone product in their lifetime completed two interviews before (January-March 2014: Wave 1) and after (May-August 2014: Wave 2) introduction of reformulated oxycodone.

RESULTS

Four-fifths (81%) had tampered with the original oxycodone formulation in the month prior to Wave 1; use and attempted tampering with reformulated oxycodone amongst the sample was comparatively low at Wave 2 (29% and 19%, respectively). Reformulated oxycodone was primarily swallowed (15%), with low levels of recent successful injection (6%), chewing (2%), drinking/dissolving (1%), and smoking (<1%). Participants who tampered with original and reformulated oxycodone were socio-demographically and clinically similar to those who had only tampered with the original formulation, except the former were more likely to report prescribed oxycodone use and stealing pharmaceutical opioid, and less likely to report moderate/severe anxiety. There was significant diversity in the methods for tampering, with attempts predominantly prompted by self-experimentation (rather than informed by word-of-mouth or the internet). Participants rated reformulated oxycodone as more difficult to prepare and inject and less pleasant to use compared to the original formulation.

CONCLUSION

Current findings suggest that the introduction of the tamper-resistant product has been successful at reducing, although not necessarily eliminating, tampering with the controlled-release oxycodone formulation, with lower attractiveness for misuse. Appropriate, effective treatment options must be available with increasing availability of abuse-deterrent products, given the reduction of oxycodone tampering and use amongst a group with high rates of pharmaceutical opioid dependence.

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.

Toward a systematic approach to opioid rotation

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Costs and Consequences: A Review of Discharge Opioid Prescribing for ongoing Management of Acute Pain

Over recent years there has been a growing need for patients to be sent home from hospital with prescribed opioids for ongoing management of their acute pain. Increasingly complex surgery is being performed on a day-stay or 23-hour-stay basis and inpatients after major surgery and trauma are now discharged at a much earlier stage than in the past. However, prescription of opioids to be self-administered at home is not without risk. In addition to the potential for acute adverse effects, including opioid-induced ventilatory impairment and impairment of driving skills, a review of the literature shows that opioid use continues in some patients for some years after surgery. There are also indications that over-prescription of discharge opioids occur with a significant amount not consumed, resulting in a potentially large pool of unused opioid available for later use by either the patient or others in the community. Concerns about the potential for harm arising from prescription of opioids for ongoing acute pain management after discharge are relatively recent. However, at a time when serious problems resulting from the non-medical use of opioids have reached epidemic proportions in the community, all doctors must be aware of the potential risks and be able to identify and appropriately manage patients where there might be a risk of prolonged opioid use or misuse. Anaesthetists are ideally placed to exercise stewardship over the use of opioids, so that these drugs can maintain their rightful place in the post-discharge analgesic pharmacopoeia.

Monitoring of internet forums to evaluate reactions to the introduction of reformulated OxyContin to deter abuse

Background

Reformulating opioid analgesics to deter abuse is one approach toward improving their benefit-risk balance. To assess sentiment and attempts to defeat these products among difficult-to-reach populations of prescription drug abusers, evaluation of posts on Internet forums regarding reformulated products may be useful. A reformulated version of OxyContin (extended-release oxycodone) with physicochemical properties to deter abuse presented an opportunity to evaluate posts about the reformulation in online discussions.

Objective

The objective of this study was to use messages on Internet forums to evaluate reactions to the introduction of reformulated OxyContin and to identify methods aimed to defeat the abuse-deterrent properties of the product.

Methods

Posts collected from 7 forums between January 1, 2008 and September 30, 2013 were evaluated before and after the introduction of reformulated OxyContin on August 9, 2010. A quantitative evaluation of discussion levels across the study period and a qualitative coding of post content for OxyContin and 2 comparators for the 26 month period before and after OxyContin reformulation were conducted. Product endorsement was estimated for each product before and after reformulation as the ratio of endorsing-to-discouraging posts (ERo). Post-to-preintroduction period changes in ERos (ie, ratio of ERos) for each product were also calculated. Additionally, post content related to recipes for defeating reformulated OxyContin were evaluated from August 9, 2010 through September 2013.

Results

Over the study period, 45,936 posts related to OxyContin, 18,685 to Vicodin (hydrocodone), and 23,863 to Dilaudid (hydromorphone) were identified. The proportion of OxyContin-related posts fluctuated between 6.35 and 8.25 posts per 1000 posts before the reformulation, increased to 10.76 in Q3 2010 when reformulated OxyContin was introduced, and decreased from 9.14 in Q4 2010 to 3.46 in Q3 2013 in the period following the reformulation. The sentiment profile for OxyContin changed following reformulation; the post-to-preintroduction change in the ERo indicated reformulated OxyContin was discouraged significantly more than the original formulation (ratio of ERos=0.43, P<.001). A total of 37 recipes for circumventing the abuse-deterrent characteristics of reformulated OxyContin were observed; 32 were deemed feasible (ie, able to abuse). The frequency of posts reporting abuse of reformulated OxyContin via these recipes was low and decreased over time. Among the 5677 posts mentioning reformulated OxyContin, 825 posts discussed recipes and 498 reported abuse of reformulated OxyContin by such recipes (41 reported injecting and 128 reported snorting).

Conclusions

After introduction of physicochemical properties to deter abuse, changes in discussion of OxyContin on forums occurred reflected by a reduction in discussion levels and endorsing content. Despite discussion of recipes, there is a relatively small proportion of reported abuse of reformulated OxyContin via recipes, particularly by injecting or snorting routes. Analysis of Internet discussion is a valuable tool for monitoring the impact of abuse-deterrent formulations.

Preclinical pharmacokinetics, pharmacology and toxicology of lisdexamfetamine: a novel d-amphetamine pro-drug

Lisdexamfetamine dimesylate (LDX) is a novel pro-drug of d-amphetamine that is currently used for the treatment of attention-deficit/hyperactivity disorder in children aged ≥ 6 years and adults. LDX is enzymatically cleaved to form d-amphetamine following contact with red blood cells, which reduces the rate of appearance and magnitude of d-amphetamine concentration in the blood and hence the brain when compared with immediate-release d-amphetamine at equimolar doses. Thus, the increase of striatal dopamine efflux and subsequent increase of locomotor activity following d-amphetamine is less prominent and slower to attain maximal effect following an equimolar dose of LDX. Furthermore, unlike d-amphetamine, the pharmacodynamic effects of LDX are independent of the route of administration underlining the requirement to be hydrolyzed by contact with red blood cells. It is conceivable that these pharmacokinetic and pharmacodynamic differences may impact the psychostimulant properties of LDX in the clinic. This article reviews the preclinical pharmacokinetics, pharmacology, and toxicology of LDX. This article is part of the Special Issue entitled 'CNS Stimulants'.

Attractiveness of reformulated OxyContin(R) tablets: assessing comparative preferences and tampering potential

Reformulated OxyContin® (oxycodone HCl controlled-release or ORF) was developed as a tamper and abuse-deterrent product, to reduce the risk of product abuse, misuse and their consequences. This noninterventional single-session study asked participants who were medically-healthy recreational opioid users, aged 18 years and older, to consider how they would use commonly available supplies to tamper with placebo ORF and placebo original OxyContin (OC) tablets, and how they would assess the attractiveness of tampering and abusing ORF tablets, as compared with other opioid formulations. Participants provided information on past opioid use, and they assessed the properties of five nonhypothetical oxycodone products and two hypothetical oxycodone products. Participants provided feedback on tampering preferences, preferred tamper methods for each product, overall tampering potential and product preferences. We had 30 participants (27 males and 3 females; mean age 35 years, range 18-51) complete both the interview and tampering sessions. Participants judged OC as the most attractive, valuable, desirable and most likely to be tampered with, from among all opioid products studied. By contrast, they rated ORF as the least attractive, least valuable, least desirable, and least likely to be tampered with among all the nonhypothetical opioid products studied. These results suggested that recreational drug abusers view ORF tablets as tamper-deterrent products.

Update on prescription extended-release opioids and appropriate patient selection

Chronic pain is largely underdiagnosed, often undertreated, and expected to increase as the American population ages. Many patients with chronic pain require long-term treatment with analgesic medications, and pain management may involve use of prescription opioids for patients whose pain is inadequately controlled through other therapies. Yet because of the potential for abuse and addiction, many clinicians hesitate to treat their patients with pain with potentially beneficial agents. Finding the right opioid for the right patient is the first - often complicated - step. Ensuring that patients continue to properly use the medication while achieving therapeutic analgesic effects is the long-term goal. Combined with careful patient selection and ongoing monitoring, new formulations using extended-release technologies incorporating tamper-resistant features may help combat the growing risk of abuse or misuse, which will hopefully reduce individual suffering and the societal burden of chronic pain. The objective of this manuscript is to provide an update on extended-release opioids and to provide clinicians with a greater understanding of which patients might benefit from these new opioid formulations and how to integrate the recommended monitoring for abuse potential into clinical practice.

A comparison among tapentadol tamper-resistant formulations (TRF) and OxyContin® (non-TRF) in prescription opioid abusers

AIMS

To examine whether tamper-resistant formulations (TRFs) of tapentadol hydrochloride extended-release (ER) 50 mg (TAP50) and tapentadol hydrochloride 250 mg (TAP250) could be converted into forms amenable to intranasal (study 1) or intravenous abuse (study 2).

DESIGN

Randomized, repeated-measures study designs were employed. A non-TRF of OxyContin® 40 mg (OXY40) served as a positive control. No drug was taken in either study.

SETTING

The studies took place in an out-patient setting in New York, NY.

PARTICIPANTS

Twenty-five experienced, healthy ER oxycodone abusers participated in each study.

MEASUREMENTS

The primary outcome for study 1 was the percentage of participants who indicated that they would snort the tampered tablets, while the primary outcome for study 2 was the percentage yield of active drug in solution. Other descriptive variables, such as time spent manipulating the tablets, were also examined to characterize tampering behaviors more clearly.

FINDINGS

Tampered TRF tablets were less desirable than the tampered OXY40 tablets. Few individuals were willing to snort the TRF particles (TAP50: 24%, TAP250: 16%; OXY40: 100% P < 0.001). There was less drug extracted from the TAP50 tablet than from the OXY40 tablet (3.52 versus 37.02%, P = 0.008), and no samples from the TAP250 tablets contained analyzable solutions of the drug. It took participants longer to tamper with the TAPs (study 1: TAP50 versus OXY40, P < 0.01; TAP250 versus OXY40, P < 0.01; study 2: TAP250 versus OXY40, P < 0.05).

CONCLUSIONS

Tamper-resistant formulations of taptentadol (pain relief) tablets do not appear to be well-liked by individuals who tamper regularly with extended-release oxycodone tablets. Employing tamper-resistant technology may be a promising approach towards reducing the abuse potential of tapentadol extended-release.

Validity testing of patient objections to acceptance of tamper-resistant opioid formulations

Background

Tamper-resistant formulations (TRFs) of oral opioid drugs are intended to prevent certain types of abuse (eg, intranasal, intravenous). Patients raising objections to receiving a TRF may have valid concerns or may be seeking a formulation that can be more easily misused.

Methods

US clinicians experienced in pain management met in October 2011 to discuss common patient objections to being switched from a non-TRF opioid to a TRF of the same opioid. Retail pharmacy, health insurance, and scientific data were used to assess the potential validity of these patient objections.

Results

Clinical experience switching patients from a non-TRF to a TRF opioid was limited to oxycodone controlled release (CR), as it was the only TRF available at that time; knowledge of other TRFs was limited to the scientific literature. Common objections from patients included “costs more,” “not covered by insurance,” “can’t feel it working,” and “causes adverse events.” Objective retail pharmacy and insurance coverage information for oxycodone CR was accessible and indicated that patient objections were based on cost and coverage varied by insurer. Unpublished trial results (ClinicalTrials.gov) revealed that TRF oxycodone CR has a slower initial release than the non-TRF formulation, which may reduce positive subjective effects. The complaint “I can’t feel it working” may reflect lessened positive subjective effects rather than reduced analgesic efficacy. Most tolerability complaints lacked objective support.

Conclusion

The general process used to assess the validity of patient objections to TRF oxycodone CR may be applied to other TRFs once they become available. Publication of clinical data on TRFs would help clinicians to appropriately weigh patient concerns.

Primary care considerations of the pharmacokinetics and clinical use of extended-release opioids in treating patients with chronic noncancer pain

Extended-release (ER) opioid analgesics are associated with prolonged analgesia and greater stability in pain relief compared with immediate-release formulations. Due to the pharmacokinetic (PK) characteristics of ER opioids and additional clinical advantages, the use of ER opioids for patients with moderate-to-severe chronic noncancer pain has increased. Primary care physicians are the major prescribers of opioids and require an in-depth understanding of the risks and benefits of opioid treatment in pain management. With appropriate knowledge of PK profiles and clinical outcomes of commonly prescribed ER opioids, primary care physicians can safely and effectively manage this patient population. In addition, the development of ER opioids with abuse-deterrent features marks an important milestone in potentially reducing abuse and may be factored into the clinical decision-making process. This article provides a comprehensive review of the PK and clinical effects of ER opioids and discusses novel ER opioid formulations that may limit abuse potential.

Designing opioids that deter abuse

Prescription opioid formulations designed to resist or deter abuse are an important step in reducing opioid abuse. In creating these new formulations, the paradigm of drug development target should be introduced. Biological targets relating to the nature of addiction may pose insurmountable hurdles based on our current knowledge and technology, but products that use behavioral targets seem logical and feasible. The population of opioid abusers is large and diverse so behavioral targets are more challenging than they appear at first glance. Furthermore, we need to find ways to correlate behavioral observations of drug liking to actual use and abuse patterns. This may involve revisiting some pharmacodynamic concepts in light of drug effect rather than peak concentration. In this paper we present several new opioid analgesic agents designed to resist or deter abuse using physical barriers, the inclusion of an opioid agonist or antagonist, an aversive agent, and a prodrug formulation. Further, this paper also provides insight into the challenges facing drug discovery in this field. Designing and screening for opioids intended to resist or deter abuse is an important step to meet the public health challenge of burgeoning prescription opioid abuse.

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.

Randomized, double-blind, placebo-controlled and active-controlled study to assess the relative abuse potential of oxycodone HCl-niacin tablets compared with oxycodone alone in nondependent, recreational opioid users

Background

Abuse-deterrent formulations attempt to address public health and societal concerns regarding opioid abuse. Oxycodone HCl-niacin tablets combine oxycodone HCl with niacin and functional inactive excipients to create potential barriers to oral, intranasal, and intravenous abuse. This study compared the relative abuse potential of oral immediate-release oxycodone HCl-niacin with that of oral immediate-release oxycodone HCl and placebo in nondependent, recreational opioid users.

Methods

Forty-nine participants received oxycodone HCl-niacin 40/240 mg and 80/480 mg, oxycodone 40 mg and 80 mg, and placebo in a randomized, double-blind, placebo-controlled and active-controlled, five-way crossover study. Primary endpoints based on a bipolar 100 mm visual analog scale for drug liking were area under effect curve (AUE_0–1h, AUE_0–2h, AUE_0–3h), peak disliking, and effect at 0.5 hours post-dose (E_0.5h). Other endpoints included take drug again assessment, overall drug liking, and pupillometry.

Results

There were statistically significant differences between oxycodone HCl-niacin and oxycodone HCl doses for all primary endpoints (P < 0.0001, all comparisons), suggesting reduced abuse potential with oxycodone HCl-niacin. Take drug again and overall drug liking showed greater liking of oxycodone alone. Oxycodone HCl-niacin 80/480 mg had consistently lower liking assessments than oxycodone HCl-niacin 40/240 mg, suggesting a dose-response to the aversive effects of niacin. Opioid-related adverse events were similar for equivalent oxycodone doses. The treatment-emergent adverse events most specifically associated with oxycodone HCl-niacin (ie, skin-burning sensation, warmth, and flushing) were consistent with the expected vasocutaneous effects of niacin. No serious adverse events were reported.

Conclusion

Oxycodone HCl-niacin tablets may, in a dose-dependent manner, decrease the potential for oral abuse of oxycodone without unexpected adverse events or clinically signifi-cant differences in safety parameters compared with oxycodone alone. Although statistically powered, the small size of the study sample and the characteristics of its participants may not be generalizable to the population that abuses prescription opioid medications.

Measuring online endorsement of prescription opioids abuse: an integrative methodology

PURPOSE

The ability to track prescription opioid abusers' endorsement of compounds may be valuable in forecasting abuser's preferences. We developed a metric, referred to as the Endorsement Ratio (ERo), to explore the feasibility of quantifying the sentiment expressed by opioid abusers who post online about prescription opioid products.

METHODS

Internet posts written between April 1, 2010 and March 31, 2011 and related to six prescription opioid compounds (oxycodone ER, hydrocodone, hydromorphone, oxymorphone, morphine ER, and tramadol) were identified and qualitatively coded. A mixed effects multinomial logistic regression was employed to model the probability of observing endorsing, discouraging, mixed, or unclear messages per compound. Endorsement-to-discouragement ratio (ERo) and ratio of endorsement-to-discouragement ratios (RERo) were estimated for each compound.

RESULTS

In the study sample of 12 838 Internet posts, a ranking of endorsement could be established, with oxymorphone as most endorsed (ERo = 7.39), followed by hydromorphone (ERo = 5.02), hydrocodone (ERo = 3.53), oxycodone ER (ERo = 3.23), morphine ER (ERo = 2.71), and tramadol (ERo = 1.76). Relative rankings of products required that route of administration be considered.

CONCLUSIONS

This study expands existing Internet monitoring approaches by developing a metric to estimate the endorsement of specific prescription opioid compounds as viewed through the lens of Internet communities. Route of administration must be taken into account when examining preferences of drug abusers for various products. This study did not assess whether the novel metric is valid with respect to classification of abuse rates of different drugs. Further studies examining external validation studies are warranted.