Routes of abuse of prescription opioid analgesics: a review and assessment of the potential impact of abuse-deterrent formulations

Review of Opioid Abuse-Deterrent Formulations: Impact and Barriers to Access

The misuse and abuse of opioid analgesics continue to pose a serious public health concern, but for some patients, opioids remain an important analgesic option. Extended-release (ER) opioid formulations are effective for treating chronic pain and are supported by multiple 12-week efficacy studies. ER opioids often contain a high opioid content, and similar to immediate-release (IR) formulations, are subject to abuse, misuse, and diversion. Unintentional misuse may also occur when ER formulations are manipulated for medicinal administration, such as crushing a dose for easier oral intake. As part of a multipronged strategy designed to fight the opioid epidemic, abuse-deterrent formulations (ADFs) were developed to deter misuse, abuse, and diversion of opioids by making manipulation more difficult and nonoral routes of administration less rewarding. Although ADF opioids have been shown to decrease rates of abuse and diversion, they are not equally effective in terms of deterring manipulation for abuse or misuse. Xtampza ER utilizes DETERx technology, which allows it to retain ER characteristics when chewed or crushed, making it the only ER opioid without a boxed warning against these types of manipulation. OxyContin was also developed as an ADF but uses RESISTEC technology, making the tablet hard to crush and viscous in aqueous solutions. ADF utilization has been hampered by patient access issues, including high prices due to lack of insurance coverage. Postmarket real-world studies demonstrate lower rates of abuse, misuse, and diversion for ADF ER opioids compared with non-ADF formulations. However, similar studies comparing abuse-related effectiveness and health care costs for ADF opioids are warranted if clinicians are expected to utilize these potentially safer opioid formulations. These studies would support further education surrounding the benefits and utilization of ADFs and manipulation potential of different ADFs.

Rapid appearance of negative emotion during oral fentanyl self-administration in male and female rats

Opioid use disorder has become an epidemic in the United States, fuelled by the widespread availability of fentanyl, which produces rapid and intense euphoria followed by severe withdrawal and emotional distress. We developed a new preclinical model of fentanyl seeking in outbred male and female rats using volitional oral self-administration (SA) that can be readily applied in labs without intravascular access. Using a traditional two-lever operant procedure, rats learned to take oral fentanyl vigorously, escalated intake across sessions, and readily reinstated responding to conditioned cues after extinction. Oral SA also revealed individual and sex differences that are essential to studying substance use risk propensity. During a behavioural economics task, rats displayed inelastic demand curves and maintained stable intake across a wide range of fentanyl concentrations. Oral SA was also neatly patterned, with distinct 'loading' and 'maintenance' phases of responding within each session. Using our software DeepSqueak, we analysed ultrasonic vocalizations (USVs), which are innate expressions of current emotional state in rats. Rats produced 50 kHz USVs during loading then shifted quickly to 22 kHz calls despite ongoing maintenance of oral fentanyl taking, reflecting a transition to negative reinforcement. Using fibre photometry, we found that the lateral habenula differentially processed drug cues and drug consumption depending on affective state, with potentiated modulation by drug cues and consumption during the negative affective maintenance phase. Together, these results indicate a rapid progression from positive to negative reinforcement occurs even within an active drug taking session, revealing a within-session opponent process.

Opioid utilization after lower extremity amputation for peripheral vascular disease and discharge prescribing recommendations

OBJECTIVES

Opioids are commonly used for pain control after lower extremity amputations (LEA)-below the knee amputations (BKA) and above the knee amputations (AKA). Well-defined benchmarks for prescription requirements after amputation are deficient. This analysis evaluated opioid utilization after amputation to identify high-risk patients and provide recommendations for post-hospitalization opioid prescriptions at discharge.

METHODS

Patients undergoing LEA (2008-2016) with identified peripheral vascular disease were selected from Cerner's Health Facts® database using ICD-9 and 10 diagnosis and procedure codes. Patient demographics, disease severity, comorbidities, and hospital characteristics were evaluated. Post-operative opioid medications administered intravenously and orally during the hospital stay were identified from the data and converted to Morphine Milligram Equivalent per day (MME/d) for an evaluation and comparison during the index hospitalization. Descriptive statistics were used to report continuous and dichotomous variables. Dichotomous variables are reported as n (%) and continuous variables are reported as mean ± standard deviation (SD). Chi-square and T-tests were used as appropriate.

RESULTS

2399 patients who underwent AKA or BKA with peripheral vascular disease were evaluated. Sixty-three percent of the cohort was male, 67% Caucasian, and 42% married, and 58% had a Charlson index >3. The majority of patients had an average length of hospital stay of 5.7 days (M = 5.72, SD = 4.56). Patient groups that used significantly higher MME/d in the early postop period included: BKA (29.2 vs 20.7, p = 0.006), males (62.6 vs 54.0, p < 0.0001), Caucasians (64.3 vs 44.7, p < 0.0001), younger patients (69.6 vs 54.0, p < 0.0001), and those at non-training institutions (66.7 vs 56.7, p < 0.0001). Patients whose hospital stay was greater than 6 days were found to have increased opioid utilization likely secondary to index complications. For those discharged by post-operative day 7, the mean MME utilized on postop day 1 was 59.5 and decreased to a mean MME/d utilization prior to discharge of 17.6.

CONCLUSIONS

This analysis demonstrates that younger patients, males, patients with BKAs, and those who receive amputations for vascular disease at non-training institutions have higher post-operative opioid utilization during the hospital stay. At the time of discharge, patients utilized an average of 17.6 MME/d which equates to approximately three hydrocodone/acetaminophen 5/325 mg tablets per day. Based on these findings, vascular surgeons are likely over prescribing opioids at discharge and must be cognizant of appropriate dosing quantities. Prescriptions at discharge should reflect the daily utilization described from this analysis and tapered to avoid chronic utilization, overdose, and possible death.

Precautions in the management of opioid agonist therapy: from target population characteristics to new formulations and post-marketing monitoring - a focus on the Italian system

Opioid use disorder (OUD) is a serious medical condition with vast social, health and economic impact. Individuals with OUD are prescribed opioid agonist therapies, such as methadone, levomethadone, buprenorphine or naloxone/buprenorphine, to reduce the risks associated with illegal substance abuse, eventually leading to opioid use abstinence. The OUD population has peculiar frailties, mainly related to the psychiatric sphere, which may jeopardize their therapeutic course. Amongst the possible phenomena that may contribute to treatment failure, opioid agonist therapy misuse and diversion are of utmost importance, leading to serious repercussions for patients as well as for national health systems. To minimize the consequences related to these practices, it is necessary to implement cross-cutting precautions, from the formulation of abuse-deterrent drugs to the implementation of a national monitoring system that oversees the health situation and signals when action is needed. Based on these premises, this article focuses on data and insights concerning the Italian territory.

Public health and medical preparedness for mass casualties from the deliberate release of synthetic opioids

The large amounts of opioids and the emergence of increasingly potent illicitly manufactured synthetic opioids circulating in the unregulated drug supply in North America and Europe are fueling not only the ongoing public health crisis of overdose deaths but also raise the risk of another type of disaster: deliberate opioid release with the intention to cause mass harm. Synthetic opioids are highly potent, rapidly acting, can cause fatal ventilatory depression, are widely available, and have the potential to be disseminated for mass exposure, for example, if effectively formulated, via inhalation or ingestion. As in many other chemical incidents, the health consequences of a deliberate release of synthetic opioid would manifest quickly, within minutes. Such an incident is unlikely, but the consequences could be grave. Awareness of the risk of this type of incident and preparedness to respond are required to save lives and reduce illness. Coordinated planning across the entire local community emergency response system is also critical. The ability to rapidly recognize the opioid toxidrome, education on personal protective actions, and training in medical management of individuals experiencing an opioid overdose are key components of preparedness for an opioid mass casualty incident.

Rapid appearance of negative emotion during oral fentanyl self-administration in male and female rats

Opioid use disorder has become an epidemic in the United States, fueled by the widespread availability of fentanyl, which produces rapid and intense euphoria followed by severe withdrawal and emotional distress. We developed a new preclinical model of fentanyl seeking in outbred male and female rats using volitional oral self-administration that can be readily applied in labs without intravascular access. Using a traditional two lever operant procedure, rats learned to take oral fentanyl vigorously, escalated intake across sessions, and readily reinstated responding to conditioned cues after extinction. Oral self-administration also revealed individual and sex differences that are essential to studying substance use risk propensity. During a behavioral economics task, rats displayed inelastic demand curves and maintained stable intake across a wide range of fentanyl concentrations. Oral SA was also neatly patterned, with distinct "loading" and "maintenance" phases of responding within each session. Using our software DeepSqueak, we analyzed thousands of ultrasonic vocalizations (USVs), which are innate expressions of current emotional state in rats. Rats produced 50 kHz USVs during loading then shifted quickly to 22 kHz calls despite ongoing maintenance oral fentanyl taking, reflecting a transition to negative reinforcement. Using fiber photometry, we found that the lateral habenula differentially processed drug-cues and drug-consumption depending on affective state, with potentiated modulation by drug cues and consumption during the negative affective maintenance phase. Together, these results indicate a rapid progression from positive to negative reinforcement occurs even within an active drug taking session, revealing a within-session opponent process.

Recreational marijuana laws and the misuse of prescription opioids: Evidence from National Survey on Drug Use and Health microdata

Several studies have concluded that legalizing medical marijuana can reduce deaths from opioid overdoses. Drawing on micro data from the National Survey on Drug Use and Health, a survey uniquely suited to assessing patterns of substance use, we examine the relationship between recreational marijuana laws (RMLs) and the misuse of prescription opioids. Using a standard difference-in-differences (DD) regression model, we find that RML adoption reduces the likelihood of frequently misusing prescription opioids such as OxyContin, Percocet, and Vicodin. However, using a two-stage procedure designed to account for staggered treatment and dynamic effects, the DD estimate of relationship between RML adoption and the likelihood of frequently misusing prescription opioids becomes positive. Although event study estimates suggest that RML adoption leads to a decrease in the frequency of prescription opioid abuse, this effect appears to dissipate after only 2 or 3 years.

Enhanced Recovery After Surgery Patients Are Prescribed Fewer Opioids at Discharge: A Propensity-score Matched Analysis

OBJECTIVE

We aimed to compare discharge opioid prescriptions pre- and post-ERAS implementation.

SUMMARY OF BACKGROUND DATA

ERAS programs decrease inpatient opioid use, but their relationship with postdischarge opioids remains unclear.

METHODS

All patients undergoing hysterectomy between October 2016 and November 2020 and pancreatectomy or hepatectomy between April 2017 and November 2020 at 1 tertiary care center were included. For each procedure, ERAS was implemented during the study period. PSM was performed to compare pre - versus post-ERAS patients on discharge opioids (number of pills and oral morphine equivalents). Patients were matched on age, sex, race, payor, American Society of Anesthesiologists score, prior opioid use, and procedure. Sensitivity analyses in open versus minimally invasive surgery cohorts were performed.

RESULTS

A total of 3983 patients were included (1929 pre-ERAS; 2054 post-ERAS). Post-ERAS patients were younger (56.0 vs 58.4 years; P < 0.001), more often female (95.8% vs 78.1%; P < 0.001), less often white (77.2% vs 82.0%; P < 0.001), less often had prior opioid use (20.1% vs 28.1%; P < 0.001), and more often underwent hysterectomy (91.1% vs 55.7%; P < 0.001). After PSM, there were no significant differences between cohorts in baseline characteristics. Matched post-ERAS patients were prescribed fewer opioid pills (17.4 pills vs 22.0 pills; P < 0.001) and lower oral morphine equivalents (129.4 mg vs 167.6 mg; P < 0.001) than pre-ERAS patients. Sensitivity analyses confirmed these findings [open (18.8 pills vs 25.4 pills; P < 0.001 \ 138.9 mg vs 198.7 mg; P < 0.001); minimally invasive surgery (17.2 pills vs 21.1 pills; P < 0.001 \ 127.1 mg vs 160.1 mg; P < 0.001).

CONCLUSIONS

Post-ERAS patients were prescribed significantly fewer opioids at discharge compared to matched pre-ERAS patients.

Understanding syringeability and injectability of high molecular weight PEO solution through time-dependent force-distance profiles

Opioid medications play a vital role in treating moderate to severe pain. Unfortunately, many drug misusers and abusers attempt to alter the formulations or properties of these drugs by manipulation, (e.g., crushing, chewing, smoking, snorting, injecting). The intravenous (IV) route is most dangerous to abusers, as the drugs directly enter the circulatory system and produce intense euphoria. To obtain a full understanding of the impact of syringe factors (e.g., needle gauge size, needle length, syringe barrel size), on the ease of injection, we undertook a comprehensive assessment of syringeability and injectability of manipulated abuse-deterrent formulations (ADFs). A texture analyzer-based testing method was developed for the measurement of the resistance force of pulling, holding, and pushing phases of injections. Results showed that the finer needle gauge sizes required higher injection force to withdraw drug solutions. In addition, the syringed liquid volume was highly dependent on needle gauge size, holding time, and sample viscosity. In most cases, a lower needle gauge number and a longer holding time increased the syringed volume. Needle length was highly correlated to injection force (R² = 0.99). Using longer needles to inject drug solution requires greater force. Furthermore, large barrel size was correlated to pushing force (R² = 0.99); thus, increasing the difficulty of pushing the plunger of a large syringe with one hand. Finally, relationships between injection force, sample viscosity, and testing conditions were elucidated using a mathematical model, which could be used in the future to assess and predict injection force of solution samples.

Stability of Abuse-deterrent properties of PEO-based Abuse-deterrent formulation

Abuse of opioid drug products is a national health crisis in the US. To deter abuse, a number of drug products with abuse-deterrent (AD) properties have been approved by the US Food and Drug Administration (FDA). For abuse deterrence, it is critical to maintain the AD properties during the product shelf life. However, no information on the stability of AD properties during product shelf life is publicly available. In this study, stability of AD properties of surrogate AD formulation (ADF) of opioid active pharmaceutical ingredients (APIs) were studied. Surrogate extended release (ER) AD tablets were prepared by direct compression using Diltiazem HCl (model drug), polyethylene oxide (PEO WSR 301) polymer and magnesium stearate followed by curing at 70 °C for 30 mins. The stability studies were conducted at 25 °C/60 % RH and 40 °C/75 % RH storage conditions for 12 months (M) and 6 months (M), respectively. In vitro characterization and evaluation of AD properties of tablets were performed. As anticipated, the curing process increased the crushing strength of the tablets. However, the tablets could still be manipulated and compromised leading to an enhancement in the amount of drug extracted in solvents (e.g., water, alcohol), regardless of extraction temperature as well as tablet storage condition and time. Furthermore, the granule particle size as well as viscosity in water of manipulated samples were found to be lower for tablets stored at 25 °C/60 % RH or 40 °C/75 % RH for 12 M or 3 M/6M, respectively. The changes in AD properties eased the syringeability of hydrated samples and ultimately led to the withdrawal of higher amounts of drug into the syringe, thereby, impacting the abuse deterrence potential of the formulation by an IV route. These data demonstrated that the stability of AD properties (i.e., granule particle size, viscosity and syringeability-injectability) of PEO-based tablets was dependent on the storage condition. In conclusion, the design of AD formulation and setting of product quality profile should take into consideration the stability of AD properties during the product shelf life.

PLA-PCL microsphere formulation to deter abuse of prescription opioids by smoking

Opioids are commonly prescribed across the United States (US) for pain relief, despite their highly addictive nature that often leads to abuse and overdose deaths. Abuse deterrent formulations (ADFs) for prescription opioids make the non-therapeutic use of these drugs more difficult and less satisfying. Although approximately one-third of surveyed abusers in the US reported smoking opioids, to our knowledge, no commercialized ADF effectively prevents opioid smoking. Here, we report a novel approach to deter smoking of a model prescription opioid drug, thebaine (THB), by using polymer blend microspheres (MS) comprising polylactic acid (PLA) and polycaprolactone (PCL). We utilized high-performance liquid chromatography (HPLC) and thermogravimetric analysis (TGA) to test the ability of PLA-PCL MS to limit the escape of vaporized THB. Additionally, we compared the abuse-deterrent potential of PLA-PCL MS to that of activated carbon (AC) and mesoporous silica (MPS), two materials with excellent drug-adsorbing properties. Our MS formulation was effective in reducing the amount of both active drug and thermal degradation products in the vapor generated upon heating of THB. These results support that PLA-PCL microspheres can be co-formulated in a tablet with common prescription opioids to deter their abuse via the smoking route.

The effect of concurrent access to alcohol and oxycodone on self-administration and reinstatement in rats

RATIONALE

Although polysubstance use is highly prevalent, preclinical studies that assess voluntary consumption of multiple substances at the same time are rather uncommon. Overlooking drug taking patterns commonly observed in humans may limit the translational value of preclinical models.

OBJECTIVES

Here, we aimed to develop a model of polysubstance use that could be used to assess oral operant self-administration patterns under concurrent access to alcohol and the prescription opioid oxycodone.

METHODS

After a training period where animals associated specific cues and levers with each drug, rats self-administered alcohol and oxycodone solutions concurrently in daily sessions. Oxycodone was then removed to assess potential changes in alcohol consumption. The role of cues and stress on alcohol consumption and oxycodone seeking was also examined under reinstatement conditions.

RESULTS

We found that females consumed more alcohol and oxycodone than males when given access to both drugs, and this effect on alcohol intake persisted when oxycodone was removed. Additionally, re-exposure to oxycodone cues in combination with the administration of the pharmacological stressor yohimbine drove reinstatement of oxycodone seeking in females but did not have a strong effect in males, possibly due to low levels of oxycodone intake during active self-administration in male rats. Additionally, yohimbine drove increased alcohol consumption, in line with prior findings from our group and others.

CONCLUSIONS

Taken together, this study demonstrates that rats will concurrently self-administer both oxycodone and alcohol in operant chambers, and this procedure can serve as a platform for future investigations in polysubstance use and relapse-like behavior.

Model-Based Analysis of the Influence of Alcohol Use and Age on Pharmacokinetics-Pharmacodynamics of Oral Oxycodone in Middle-Age and Older Community Dwelling Adults

Little is known on how opioid responses vary by age and in the presence of alcohol consumption. This model-based pharmacokinetic-pharmacodynamic (PK-PD) analysis quantified the impact of age and alcohol use on pupillometry and cold pressor test (CPT) PD based on data from an open label study of immediate-release 10 mg oral oxycodone in middle-age and older adults (age 35-85) without severe functional limitations. PK and pupillometry assessments were obtained on 11 occasions over 8 hours. CPT was administered at 1.5, 5 and 8 hours post oxycodone dosing. The study consisted of 62 older adults (age 60+) and 66 middle-age adults (age 35-59), with 82% meeting the unhealthy drinking criteria. Oral oxycodone PK were well described using a one compartment model with a sequential zero to first order absorption process. Recent alcohol use measures were selected a priori. for the analysis. Inhibitory Emax and linear direct effect PD models described the respective pupillometry and CPT data using simultaneous PK-PD analysis in MONOLIX. This analysis demonstrated an influence of age on clearance and bodyweight on the distribution volume of oxycodone, alcohol consumption was not noted to alter oxycodone PK. Oxycodone pupillometry PD were influenced by the level of subject-reported alcohol consumption (AUDIT-C), alcohol use biomarker blood phosphatidylethanol, previous cannabis use, and age. Over the opioid exposure range of the study, none of the covariables including alcohol and age were noted to affect CPT PD. Additional clinical studies are needed to further probe the clinical consequences of opioid-alcohol-age interaction. This article is protected by copyright. All rights reserved.

Stress reveals a specific behavioral phenotype for opioid abuse susceptibility

Susceptibility to stress has long been considered important for the development of substance use disorders. Nonetheless, behavioral and physiological responses to stress are highly variable, making it difficult to identify the individuals who are most likely to abuse drugs. In the present study, we employed a comprehensive battery of tests for negative valence behaviors and nociception to identify individuals predisposed to opioid seeking following oral opioid self-administration. Furthermore, we examined how this profile was affected by a history of stress. We observed that mice receiving foot shock stress failed to exhibit a preference for sucrose, showed increased immobility in the forced swim task, and exhibited mechanical hypersensitivity when compared to controls. When considering these behaviors in light of future fentanyl-seeking responses, we observed that heightened mechanical sensitivity corresponded to higher opioid preference in mice with a history of stress, but not controls. Moreover, we were surprised to discover that paradoxically high sucrose preferences predicted fentanyl preference in shock mice, while signs of anhedonia predicted fentanyl preference in controls. Taken together, these results indicate that stress can act as a physiological modulator, shifting profiles of opioid abuse susceptibility depending on an individual's history.

A limited access oral oxycodone paradigm produces physical dependence and mesocorticolimbic region-dependent increases in DeltaFosB expression without preference

The abuse of oral formulations of prescription opioids has precipitated the current opioid epidemic. We developed an oral oxycodone consumption model consisting of a limited access (4 h) two-bottle choice drinking in the dark (TBC-DID) paradigm and quantified dependence with naloxone challenge using mice of both sexes. We also assessed neurobiological correlates of withdrawal and dependence elicited via oral oxycodone consumption using immunohistochemistry for DeltaFosB (ΔFosB), a transcription factor described as a molecular marker for drug addiction. Neither sex developed a preference for the oxycodone bottle, irrespective of oxycodone concentration, bottle position or prior water restriction. Mice that volitionally consumed oxycodone exhibited hyperlocomotion in an open field test and supraspinal but not spinally-mediated antinociception. Both sexes also developed robust, dose-dependent levels of opioid withdrawal that was precipitated by the opioid antagonist naloxone. Oral oxycodone consumption followed by naloxone challenge led to mesocorticolimbic region-dependent increases in the number of ΔFosB expressing cells. Naloxone-precipitated withdrawal jumps, but not the oxycodone bottle % preference, was positively correlated with the number of ΔFosB expressing cells specifically in the nucleus accumbens shell. Thus, limited access oral consumption of oxycodone produced physical dependence and increased ΔFosB expression despite the absence of opioid preference. Our TBC-DID paradigm allows for the study of oral opioid consumption in a simple, high-throughput manner and elucidates the underlying neurobiological substrates that accompany opioid-induced physical dependence.

Dilemma of Addiction and Respiratory Depression in the Treatment of Pain: A Prototypical Endomorphin as a New Approach

OBJECTIVE

Although mu-opioid receptor agonists have been the mainstay of analgesic regimens for moderate to severe pain, they are associated with serious side effects, risks, and limitations. We evaluate the most serious risks associated with conventional opioids and compare these with the pharmacology of CYT-1010, a prototypical endomorphin and mu-opioid receptor agonist.

RESULTS

Addiction and respiratory depression are serious risks of traditional mu-opioid analgesics. Mitigation strategies have been inadequate at addressing the opioid crisis and may interfere with the effective treatment of pain. Improved understanding of mu-opioid receptor biology and the discovery in 1997 of an additional and unique family of endogenous opioid peptides (endomorphins) have provided a pathway for dissociating analgesia from opioid-related adverse events and developing new classes of mu-opioid receptor agonists that use biased signaling and/or target novel sites to produce analgesia with reduced side effect liability. Endomorphin-1 and -2 are endogenous opioid peptides highly selective for mu-opioid receptors that exhibit potent analgesia with reduced side effects. CYT-1010 is a cyclized, D-lysine-containing analog of endomorphin-1 with a novel mechanism of action targeting traditional mu- and exon 11/truncated mu-opioid receptor 6TM variants. CYT-1010 preclinical data have demonstrated reduced abuse potential and analgesic potency exceeding that of morphine. In an initial phase 1 clinical study, CYT-1010 demonstrated significant analgesia vs baseline and no respiratory depression at the dose levels tested.

CONCLUSIONS

CYT-1010 and other novel mu-opioid receptor agonists in clinical development are promising alternatives to conventional opioids that may offer the possibility of safer treatment of moderate to severe pain.

Using contact-based education to destigmatize opioid use disorder among medical students

All first- and second-year (i.e., pre-clinical) medical students at a large, Midwestern medical school with three campuses were invited to participate in a two-arm, parallel educational study comparing the efficacy of two types of curricular interventions. Students at the main campus attended the modified contact-based education panel or the didactic lecture in person, while students at the two distance campuses attended the modified contact-based education or lecture remotely using the University's videoconferencing system. Impact: A total of 109 students participated in the study (average age 24.2 years (SD = 2.6), 64.2% female, 79.8% white, 56.0% second-year students, 67.9% attended on main campus, lecture = 52 participants, modified contact-based = 57 participants). Baseline responses were similar across groups. Following the session, participants in both interventions rated drug abuse (percent increase = 21.2%, p < .001) and prescription drug diversion (percent increase = 7.6%, p = .004) as more serious problems. Participants from both interventions expressed increased confidence in caring for patients with OUD (percent increase = 45.5%, p < .001) and increased interest in pursuing MAT training (percent increase = 21.5%, p = .04). Both curricular interventions were equally effective at reducing OUD stigma with a significant 8.2% decrease in total stigma scores and a large effect size (p < .001, η_p² = .34). Lastly, participants with lower post-assessment OUD stigma scores were more likely to indicate that they would pursue additional training to provide MAT (p = .02). Lessons learned: Exposure to opioid-specific education with a focus on MAT and recovery, regardless of education type, positively affected opioid-related postgraduate intentions and reduced OUD stigma. Notably, these findings suggest that there are multiple efficacious techniques to reduce OUD stigma during preclinical training.

Effect of alkalizing agent on abuse deterrent potential of multiple-unit ingestion of bilayer abuse-deterrent extended-release tablets using propranolol as model drug for opioids overdose crisis

The objective of present study is to develop bilayer abuse-deterrent extended-release tablets (ADERTs) using propranolol HCl as model drug for opioids overdose crisis. Bilayer ADERTs were fabricated by direct compression and formulated with polymer matrix in extended-release drug layer coupled with alkalizing and aversive agents in fast-disintegrating pH modifying layer. Various alkalizing agents, like magnesium hydroxide, aluminum hydroxide, calcium carbonate, and calcium hydroxide, were evaluated for their abuse-deterrent potential via in-vitro drug release and extraction studies. Based on the outcomes, magnesium hydroxide was selected as an alkalizing agent, since it raised the pH of dissolving media near to pKa of the drug studied in this investigation. The formulated bilayer ADERTs with magnesium hydroxide provided similar drug release profiles as compared to conventional extended-release tablets for single-unit ingestion. However, upon ingestion of multiple-unit bilayer ADERTs, the fast-disintegrating pH modifying layer increases pH of dissolving media, while extended-release layer increases micro-environmental pH within tablets. Retarding drug release owing to low solubility of basic drug at higher pH was observed. Therefore, the application of alkalizing agent has impact on pH-dependent solubility of drug like opioids and demonstrate its useful potential to be incorporated in bilayer ADERTs for opioids overdose crisis.

Acute Pain Management of Chronic Pain Patients in Ambulatory Surgery Centers

PURPOSE OF REVIEW

With the widespread growth of ambulatory surgery centers (ASCs), the number and diversity of operations performed in the outpatient setting continue to increase. In parallel, there is an increase in the proportion of patients with a history of chronic opioid use and misuse undergoing elective surgery. Patients with such opioid tolerance present a unique challenge in the ambulatory setting, given their increased requirement for postoperative opioids. Guidelines for managing perioperative pain, anticipating postoperative opioid requirements and a discharge plan to wean off of opioids, are therefore needed.

RECENT FINDINGS

Expert guidelines suggest using multimodal analgesia including non-opioid analgesics and regional/neuraxial anesthesia whenever possible. However, there exists variability in care, resulting in challenges in perioperative pain management. In a recent study of same-day admission patients, anesthesiologists correctly identified most opioid-tolerant patients, but used non-opioid analgesics only half the time. The concept of a focused ambulatory pain specialist on site at each ASC has been suggested, who in addition to providing safe anesthesia, could intervene early once problematic pain issues are recognized. This review focuses on perioperative pain management in three subsets of patients who exhibit opioid tolerance: those on large doses of opioids (including abuse-deterrent formulations) for chronic non-malignant or malignant pain; those who have ongoing opioid misuse; and those who were prior addicts and are now on methadone/suboxone maintenance. We also discuss perioperative pain management for patients who have implanted devices such as spinal cord stimulators and intrathecal pain pumps.

Patterns of Routes of Administration and Drug Tampering for Nonmedical Opioid Consumption: Data Mining and Content Analysis of Reddit Discussions

Background

The complex unfolding of the US opioid epidemic in the last 20 years has been the subject of a large body of medical and pharmacological research, and it has sparked a multidisciplinary discussion on how to implement interventions and policies to effectively control its impact on public health.

Objective

This study leverages Reddit, a social media platform, as the primary data source to investigate the opioid crisis. We aimed to find a large cohort of Reddit users interested in discussing the use of opioids, trace the temporal evolution of their interest, and extensively characterize patterns of the nonmedical consumption of opioids, with a focus on routes of administration and drug tampering.

Methods

We used a semiautomatic information retrieval algorithm to identify subreddits discussing nonmedical opioid consumption and developed a methodology based on word embedding to find alternative colloquial and nonmedical terms referring to opioid substances, routes of administration, and drug-tampering methods. We modeled the preferences of adoption of substances and routes of administration, estimating their prevalence and temporal unfolding. Ultimately, through the evaluation of odds ratios based on co-mentions, we measured the strength of association between opioid substances, routes of administration, and drug tampering.

Results

We identified 32 subreddits discussing nonmedical opioid usage from 2014 to 2018 and observed the evolution of interest among over 86,000 Reddit users potentially involved in firsthand opioid usage. We learned the language model of opioid consumption and provided alternative vocabularies for opioid substances, routes of administration, and drug tampering. A data-driven taxonomy of nonmedical routes of administration was proposed. We modeled the temporal evolution of interest in opioid consumption by ranking the popularity of the adoption of opioid substances and routes of administration, observing relevant trends, such as the surge in synthetic opioids like fentanyl and an increasing interest in rectal administration. In addition, we measured the strength of association between drug tampering, routes of administration, and substance consumption, finding evidence of understudied abusive behaviors, like chewing fentanyl patches and dissolving buprenorphine sublingually.

Conclusions

This work investigated some important consumption-related aspects of the opioid epidemic using Reddit data. We believe that our approach may provide a novel perspective for a more comprehensive understanding of nonmedical abuse of opioids substances and inform the prevention, treatment, and control of the public health effects.

Oral prescription opioid-seeking behavior in male and female mice

A significant portion of prescription opioid users self-administer orally rather than intravenously. Animal models of opioid addiction have demonstrated that intravenous cues are sufficient to cause drug seeking. However, intravenous models may not characterize oral users, and the preference to self-administer orally appears to be partially influenced by the user's sex. Our objectives were to determine whether oral opioid-associated cues are sufficient for relapse and whether sex differences exist in relapse susceptibility. Mice orally self-administered escalating doses of oxycodone under postprandial (prefed) or non-postprandial (no prefeeding) conditions. Both sexes demonstrated cue-induced reinstatement following abstinence. In separate mice, we found that oral oxycodone cues were sufficient to reinstate extinguished oral oxycodone-seeking behavior following abstinence without prior postprandial or water self-administration training. During self-administration, we incidentally found that female mice earned significantly more mg/kg oxycodone than male mice. Follow-up studies indicated sex differences in psychomotor stimulation and plasma oxycodone/oxymorphone following oral oxycodone administration. In addition, gonadal studies were performed in which we found divergent responses where ovariectomy-enhanced and orchiectomy-suppressed oral self-administration. While the suppressive effects of orchiectomy were identified across doses and postprandial conditions, the enhancing effects of ovariectomy were selective to non-postprandial conditions. These studies establish that (a) oral drug cues are sufficient to cause reinstatement that is independent of prandial conditions and water-seeking behavior, (b) earned oral oxycodone is larger in female mice compared with male mice potentially through differences in psychomotor stimulation and drug metabolism, and (c) gonadectomy produces divergent effects on oral oxycodone self-administration between sexes.

Demand for fentanyl becomes inelastic following extended access to fentanyl vapor self-administration

Opioid use disorder imposes great societal harm in the United States and in countries worldwide. Animal models that accurately capture motivational changes that occur in opioid dependence are critical to studying this disorder. The present study used a model of opioid vapor self-administration combined with a behavioral economics approach to determine whether rats would be more motivated to "work" to defend their baseline intake of fentanyl (i.e., more inelastic demand) following sufficiently frequent, intense, and chronic exposure to self-administered vaporized fentanyl. Male rats were allowed to respond for deliveries of 1.5-s of vaporized 10 mg/ml fentanyl solution. Following 15 sessions of short access (ShA; 1 h) vs. long access (LgA; 12 h) to self-administration, we conducted a between-sessions demand curve procedure, and observed significantly more inelastic demand for fentanyl (Essential Value; EV), and increased maximal response output (O_max) in LgA compared with ShA rats. In a subsequent phase, the unit-dose was doubled to 3 s of fentanyl vaporization. After seven ShA vs. LgA sessions, we assessed demand again and found that LgA rats, contrasted to ShA rats, demonstrated significantly higher baseline intake or "hedonic setpoint" (Q₀), in addition to significantly increased EV and O_max. These results demonstrate that extended access to self-administration of a vaporized opioid causes changes in behavioral economic metrics consistent with development of an addiction-like state in rats. The combination of the vapor model with a translationally relevant behavioral economics framework opens new avenues to study dysregulated motivational processes in substance use disorders.

Variation in Abuse-Deterrent Formulation Opioid Prescribing in California, Florida, and Kentucky in 2018

PURPOSE

Abuse-deterrent formulation (ADF) opioid analgesics have been developed as a means to address prescription opioid abuse. ADF opioid use in clinical practice is not well described in the literature. This study characterizes ADF opioid prescribing patterns in 3 diverse states.

METHODS

This study used data from prescription drug monitoring programs (PDMPs) in California, Florida, and Kentucky. The sample includes all ADF opioid prescriptions for patients ≥18 years old during the study period (CY 2018). Standardized prescribing rates were calculated by age, sex, and county rurality. The ADF opioid prescribing rate was calculated per 1,000 adult recipients of opioid analgesics.

FINDINGS

The rate of ADF prescribing per 1,000 adult recipients of opioid analgesics was nearly twice as high in Florida (14.57; 95% CI: 14.44-14.69) than in California (8.30; 95% CI: 8.22-8.37) or Kentucky (8.20; 95% CI: 8.01-8.39). ADF prescribing rates were highest among adults ages 55-74 years and among males. ADF opioid prescribing in rural counties represented a greater proportion of total patients using opioid analgesics than in metro counties in California (RR 1.40; CI: 1.28-1.53). Opposite and less pronounced variation was observed in Kentucky (RR 0.93; 95% CI: 0.88-0.98), and a significant difference was not observed in Florida (RR 0.68; 95% CI: 0.38-1.19).

CONCLUSIONS

There were significant differences in the ADF prescribing rates among the 3 states and in rural versus metro counties within 2 states. ADF opioid prescribing by age and sex showed similar trends within states. Further research is needed to elucidate contextual factors which may lead to prescribing variation.

Extended release pellets prepared by hot melt extrusion technique for abuse deterrent potential: Category-1 in-vitro evaluation

The objective of the present study was to develop extended-release (ER) hot-melt extruded (HME) abuse-deterrent pellets of acetaminophen, a model drug, by utilizing high molecular weight polyethylene oxide (PEO) and gelling agents (xanthan gum, guar gum, and gellan gum). The HME pellets were evaluated for their abuse-deterrence (AD) potential by Category-1 laboratory in-vitro evaluation parameters, including particle size reduction (PSR), small volume extraction, dissolution, viscosity, syringeability, and injectability. Further, the pellets were investigated for resistance to physical (crushing) and thermal (oven and microwave) manipulation to evaluate the strength of the AD properties. Physical manipulation studies demonstrated that the pellets were intact, extremely hard, and resistant to PSR and manipulation to bypass ER properties. Dissolution of all intact and physically manipulated pellets led to complete drug release within 8 h, and resistance to dose-dumping in 40% ethanol was observed. The drug extraction was <50% in 10 mL of ingestible and non-ingestible solvents under static, agitation, and thermal manipulation conditions with an incubation time of 30 min. The PEO/xanthan gum-based formulation showed higher viscosity, syringe and injection forces, and lower syringeable volume in all manipulation conditions compared with plain PEO pellets. These findings supported the AD potential of PEO and xanthan gum pellets against intravenous abuse.

Finding the Hidden Risk Profiles of the United States Opioid Epidemic: Using a Person-Centered Approach on a National Dataset of Noninstitutionalized Adults Reporting Opioid Misuse

Opioid misuse can lead to use disorder and other adverse outcomes. Identifying sociodemographic risk profiles and understanding misuse patterns in combination with health indicators can inform prevention science and clinical practice. A latent class analysis of opioid misuse was conducted on noninstitutionalized United States civilians aged 18 and older that reported opioid dependence or abuse in the 2017 National Survey of Drug Use and Health (n = 476; weighted n = 2,018,922). Opioid misuse was based on heroin and/or prescription pain reliever use, and associated determinants of health and mental health indicators. Five misuse profiles were identified: (1) single heroin or prescription misuse with high-income; (2) female prescription pain reliever misuse with psychological distress and suicidality; (3) younger polyopioid misuse with the highest proportion of Hispanics and heroin use; (4) older polyopioid misuse with the highest proportion of non-Hispanic blacks and disability; and (5) older non-Hispanic white male exclusive dual heroin and/or prescription misuse (27%, 20%, 38%, 10%, and 5% of sample, respectively). The identified risk profiles can inform public health practice to develop interventions for acute and immediate response by providing etiological evidence and to inform prevention and intervention efforts along the continuum from opioid initiation to use disorder.

Proper Disposal of Prescription Opioids in Southwest Virginia: Assessment of Patient, Physician, and Medical Student Beliefs and Practices

CONTEXT

Southwestern Virginia demonstrates the highest regional mortality rate from prescription opioid overdoses. Nationally, 65% of patients misusing opioid medications received them from friends and family, underscoring the need for effective disposal of unused narcotics.

OBJECTIVES

(1) To understand patient, provider, and medical student beliefs and misconceptions regarding proper methods of opioid disposal; (2) to characterize discrepancies that exist between patient self-reported habits and medical student/provider perceptions of opioid usage, disposal, and diversion.

DESIGN

Descriptive, cross-sectional, observational study.

SETTING

Large, nonprofit health care organization and allopathic medical school in Southwestern Virginia.

PARTICIPANTS

All ambulatory patients 18 years or older presenting for elective consultation at health system orthopedics department; all institutionally employed physicians with active system e-mail addresses; and all current students at the associated medical school.

MAIN OUTCOMES/MEASURES

Patients: The number who had received information regarding proper methods of opioid disposal, intended disposal method, methods of disposal considered appropriate, comfort level with opioid disposal, and demographic data. Physicians and Medical Students: The number who had received instruction regarding proper methods of opioid disposal, acceptable means of opioid disposal, most appropriate disposal method, disposal method most likely to be employed by patients, practice profile/prescribing data, and medical school year.

RESULTS

In total, 64% of patients (n = 255/750) had never received instruction from a physician regarding opioid disposal; 56% of physicians (n = 212/732) and 78% (n = 80/171) of medical students indicated that they never received formal instruction regarding methods of disposal. The majority of physicians believed that their patients are most likely to use in-home methods of disposal or store prescription medications for future use; 61% of patients indicated a preference for accessible disposal facilities.

CONCLUSIONS

The discrepancy between patient and physician responses highlights a lack of communication regarding disposal of unused opioid medications and is a target for future intervention.

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.

Development of Abuse-Deterrent Formulations Using Sucrose Acetate Isobutyrate

The objective of the present investigation was to understand the effect of sucrose acetate isobutyrate (SAIB) on abuse-deterrent properties (ADPs) of abuse-deterrent formulations (ADFs) based on Polyox™. SAIB would enhance ADPs of Polyox™-based formulations due to its glassy liquid and hydrophobic properties. Formulations were prepared by granulation followed by compression and heat curing at 90°C. The formulations were evaluated for surface morphology, hardness, manipulation in coffee grinder, particle size distribution, drug (pseudoephedrine hydrochloride) extraction in water, alcohol, 0.1 N HCl, 0.1 N NaOH at room temperature and elevated temperature using microwave and oven, syringeability and injectability, and dissolution. The heat curing of formulations significantly increased the hardness (> 490 N). Addition of SAIB imparted elasticity to formulations and decreased brittleness as indicated by lower values of work done and gradient compared to control formulations. After grinding, about 7.7-25.6% of the powder remained on the sieve (1 mm pore opening), D₉₀ was 53.1-136.7 μm more, and Q (fraction < 500 μm) was 17.8-40.7% less in SAIB-based formulations compared to control formulations. Drug extraction between control and test intact formulations was similar. However, drug extraction was 23.9-42.5% (water), 20.6-26.1% (0.1 N HCl), and 37.4-50.6% (0.1 N NaOH) less in SAIB-based powder cured and uncured formulations compared to control formulations. Dissolution varied from 65.6 ± 4.2 to 97.6 ± 4.0% in 9 h from the formulations. In conclusion, addition of SAIB to Polyox™-based ADFs has synergistic effect on ADPs. This would further decrease potential of drug abuse/misuse by various routes.

Abuse-deterrent opioid analgesics: a guide for clinicians

The US FDA has encouraged the development of abuse-deterrent formulations (ADFs) of opioid analgesics as one component in a comprehensive effort to combat prescription opioid abuse. Guidance issued by the FDA outlines three types of premarket studies for evaluating abuse deterrence: laboratory-based in vitro manipulation and extraction studies, pharmacokinetic studies and human abuse potential studies. After approval, postmarket studies are needed to evaluate the impact of an ADF product on abuse in real-world settings. This review summarizes the regulatory issues involved in the development of ADF opioids and clarifies abuse-deterrence claims in product labels, in order to assist clinicians in critically evaluating the available evidence pertaining to the abuse-deterrent features of opioid analgesics.

Therapeutic experience with tramadol for opioid dependence in a patient with chronic low back pain: a case report

Background

Long-term opioid treatment for chronic non-cancer pain has become controversial, given the increasing prevalence of opioid dependence. However, there is little information on therapeutic strategies for this condition in Japanese patients. Here, we present a case of successful management of iatrogenic opioid dependence with tramadol in a patient with chronic low back pain.

Case presentation

A 68-year-old male suffering from intractable low back pain was referred to our pain clinic. He was previously treated in another hospital with transdermal fentanyl patches 6 mg/day and fentanyl sublingual tablets (100 μg as required) for this condition. On the basis of medical examination, including a review of the patient’s medical history, physical examination, X-ray, and his family statement, we diagnosed him with iatrogenic opioid dependence due to inadequate fentanyl use. Then, we developed a treatment plan consisting in fentanyl detoxification with a weak opioid, tramadol. At first, the use of fentanyl sublingual tablets was interrupted after obtaining informed consent. Then, we reduced the dose of transdermal fentanyl 1 mg per 4–5 days replacing with oral sustained-release tramadol. The patient developed mild to moderate withdrawal symptoms during this period, which could be effectively managed by supportive treatments. The hospital psychiatry liaison team continuously provided the patient and his wife with information, counseling, and education regarding the treatment of opioid dependence. Throughout the detoxification process, his reported pain did not exacerbate, even slightly improved over time. The final prescription was sustained-release tramadol 300 mg/day without fentanyl, and his activities of daily living drastically improved. However, unfortunately, he died due to an aortic dissection of stent-graft edge 65 days after surgery.

Conclusions

Our case highlighted that sustained-release tramadol could be effectively applied as a detoxification agent for iatrogenic opioid dependence in patients with chronic non-cancer pain.

Modeling drug exposure in rodents using e-cigarettes and other electronic nicotine delivery systems

Smoking tobacco products is the leading cause of preventable death worldwide. Coordinated efforts have successfully reduced tobacco cigarette smoking in the United States; however, electronic cigarettes (e-cigarette) and other electronic nicotine delivery systems (ENDS) recently have replaced traditional cigarettes for many users. While the clinical risks associated with long-term ENDS use remain unclear, advancements in preclinical rodent models will enhance our understanding of their overall health effects. This review examines the peripheral and central effects of ENDS-mediated exposure to nicotine and other drugs of abuse in rodents and evaluates current techniques for implementing ENDS in preclinical research.

Epidemiology of severe buprenorphine exposures reported to the U.S. Poison Centers

OBJECTIVE

This study aims to evaluate the trends and risk factors of severe buprenorphine outcomes (SBO) reported to the U.S. Poison Centers (PCs).

METHODS

We queried the National Poison Data System for exposures to buprenorphine from 2011 to 2016. SBO cases were defined as exposures that resulted in either a death or major clinical outcomes. Trends were tested using Poisson regression. Characteristics of the exposures were descriptively assessed. Logistic regression was used to evaluate the risk factors of SBO.

RESULTS

SBO cases (967) reported to the PCs increased by 66.6% during this period (114-190, p < 0.001). While adults between 20 and 39 years were more frequent in the SBO group (50.4%) compared to the non-SBO group (38.7%), cases under 6 years (29.6% vs 13.8%) were more common among the non-SBO group. Intentional abuse (20.1% vs 24.9%) and suspected suicides (13.7% vs 37.5%) were significantly higher among the SBO group. Multisubstance exposures were more frequent among the SBO cases (36.4% vs 71.4%). SBO risk increased with age, with cases above 60 years (AOR: 1.66, 95% CI: 1.14-2.42) demonstrating significantly increased odds. Suspected suicide (AOR: 1.87, 95% CI: 1.53-2.28) and abuse (AOR: 1.40, 95% CI: 1.13-1.73) cases were more likely to result in a SBO. Multisubstance exposures significantly increased the risk of a SBO.

CONCLUSIONS

This study reflected an increase in the cases of SBO paralleling the rise in the buprenorphine prescriptions. Age, reasons for exposure and multi-substance exposures significantly increased the risk of SBO.

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.

Escalated Oxycodone Self-Administration Causes Differential Striatal mRNA Expression of FGFs and IEGs Following Abstinence-Associated Incubation of Oxycodone Craving

Addiction to prescribed opioids including oxycodone has reached tragic levels. Herein, we investigated the relevance of fibroblast growth factors (FGFs) and immediate early genes (IEGs) to withdrawal-induced incubation of drug craving following escalated oxycodone self-administration (SA). Rats were trained to self-administer oxycodone for 4 weeks. Seeking tests were performed at various intervals during 1 month of drug withdrawal. Rats were euthanized 1 day after the last test and nucleus accumbens and dorsal striata were dissected for use in PCR analyses. Rats given long access (LgA, 9 h), but not short access (ShA, 3 h) to drug escalated their oxycodone intake and exhibited incubation of oxycodone seeking during withdrawal. These rats exhibited dose-dependent increases in fgf2 expression in the dorsal striatum. Fgfr2 expression was also significantly increased in the striatum in LgA, but not ShA groups. Similarly, striatal c-fos and junB mRNA levels showed greater increases in LgA rats. The observations that fgf mRNA levels were more altered in the dorsal striatum than in the NAc of LgA rats suggest that changes in striatal FGF expression may be more salient to incubation of oxycodone craving than alterations in the NAc. Targeting FGF signaling pathways might offer novel strategies against opioid addiction.

Skin Delivery and Irritation Potential of Phenmetrazine as a Candidate Transdermal Formulation for Repurposed Indications

Phenmetrazine, a selective dopamine and norepinephrine releaser, previously available as an oral anorectic, is prone to be abused. This study aimed to assess the feasibility of delivering phenmetrazine via the transdermal route for a new indication, while also minimizing its abuse potential. The passive permeation of phenmetrazine through dermatomed human cadaver skin was evaluated using static Franz diffusion cells at 10 mg/mL for the fumarate salt, and at 20, 40, and 80 mg/mL for the free base in propylene glycol for 24 h. Further, oleic acid (5% w/w), oleyl alcohol (5% and 10% w/w), and lauric acid (10% w/w) were investigated as chemical permeation enhancers to enhance the delivery. Skin irritation potential was assessed using EpiDerm™ in vitro reconstructed human epidermal model. The free base showed superior 24-h delivery (8.13 ± 4.07%, 10.6 ± 2.5%, and 10.4 ± 1.4% for groups with 20, 40, and 80 mg/mL of the free base, respectively) to phenmetrazine fumarate salt (undetectable). The successful screening of effective chemical enhancers, oleyl alcohol (5% and 10% w/w), oleic acid (5% w/w), and lauric acid (10% w/w) resulted in significant enhancement of delivery. The calculated therapeutic relevant flux for the potential indication, attention deficit hyperactivity disorder, 20 μg/cm²/h was met, where a 24-mg daily dose from a 50-cm² patch was projected to be delivered to a 60-kg individual. Irritation study results suggest that formulations with therapeutically relevant delivery are likely to be non-irritant. In conclusion, it is feasible to deliver therapeutically relevant amounts of phenmetrazine via the transdermal route.

An update on the contribution of hot-melt extrusion technology to novel drug delivery in the twenty-first century: part II

INTRODUCTION

Interest in hot-melt extrusion (HME) technology for novel applications is growing day by day, which is evident from several hundred publications within the last 5 years. HME is a cost-effective, solvent free, 'green' technology utilized for various formulations with low investment costs compared to conventional technologies. HME has also earned the attention of the pharmaceutical industry by the transformation of this technology for application in continuous manufacturing.

AREAS COVERED

Part II of the review focuses on various novel opportunities or innovations of HME such as multiple component systems (co-crystals, co-amorphous systems and salts), twin-screw granulation, semi-solids, co-extrusion, abuse deterrent formulations, solid self-emulsifying drug delivery systems, chronotherapeutic drug delivery systems, and miscellaneous applications.

EXPERT OPINION

HME is being investigated as an alternative technology for preparation of multicomponent systems such as co-crystals and co-amorphous techniques. Twin-screw granulation has gained increased interest in preparation of granules via twin-screw melt granulation or twin-screw dry granulation. This novel application of the HME process provides a promising alternate approach in the formulation of granules and solid dosage forms. However, this technology may need to be further investigated for scalability aspects of these novel applications for industrial production.

Can neuroimaging help combat the opioid epidemic? A systematic review of clinical and pharmacological challenge fMRI studies with recommendations for future research

The current opioid epidemic is an urgent public health problem, with enormous individual, societal, and healthcare costs. Despite effective, evidence-based treatments, there is significant individual variability in treatment responses and relapse rates are high. In addition, the neurobiology of opioid-use disorder (OUD) and its treatment is not well understood. This review synthesizes published fMRI literature relevant to OUD, with an emphasis on findings related to opioid medications and treatment, and proposes areas for further research. We conducted a systematic literature review of Medline and Psychinfo to identify (i) fMRI studies comparing OUD and control participants; (ii) studies related to medication, treatment, abstinence or withdrawal effects in OUD; and (iii) studies involving manipulation of the opioid system in healthy individuals. Following application of exclusionary criteria (e.g., insufficient sample size), 45 studies were retained comprising data from ~1400 individuals. We found convergent evidence that individuals with OUD display widespread heightened neural activation to heroin cues. This pattern is potentiated by heroin, attenuated by medication-assisted treatments for opioids, predicts treatment response, and is reduced following extended abstinence. Nonetheless, there is a paucity of literature examining neural characteristics of OUD and its treatment. We discuss limitations of extant research and identify critical areas for future neuroimaging studies, including the urgent need for studies examining prescription opioid users, assessing sex differences and utilizing a wider range of clinically relevant task-based fMRI paradigms across different stages of addiction.

Understanding multi-pill ingestion of prescription opioids: Prevalence, characteristics, and motivation

PURPOSE

Oral use is the primary route of administration among non-medical prescription opioid users. While progression to non-oral routes and shifts to stronger opioids have been previously studied as ways to cope with tolerance, the prevalence and patterns of those who cope by increasing the number of pills/tablets ingested at one time (ie, multi-pill use) has not been assessed.

METHODS

A subset (N = 231) of treatment-seeking opioid users from a national opioid surveillance system, participating in the Researchers and Participants Interacting Directly (RAPID) Program, completed an online survey centered on multi-pill use.

RESULTS

Over two-thirds of non-medical prescription opioid users had a history of multi-pill use (67.7%), defined as ingesting four or more of the same pill, intact and at the same time. Among these (n = 154), the median maximum number of pills taken at one time was eight, with over 20% ingesting 11 or more pills in a single instance. Nearly half engaged in multi-pill ingestion more than once a day in the past month (43.8%), with accessibility to lower dose pills being the primary motivator (85.4%). Hydrocodone immediate-release (IR) compounds were by far the most frequently endorsed (90.3%), followed by oxycodone IR tablets with acetaminophen (76.0%) and oxycodone IR tablets containing no acetaminophen/ibuprofen (56.5%).

CONCLUSIONS

These results indicate that the ingestion of multiple opioid pills/tablets is extremely common among treatment-seeking opioid users. This, and other forms of non-medical oral use of prescription opioids, should be taken under consideration when developing prevention and intervention efforts targeting the opioid epidemic.

Management of Challenging Pharmacologic Issues in Chronic Pain and Substance Abuse Disorders

Drug abuse and addiction are persistent problems in the United States and around the world. This is an ongoing issue for health care providers, as substance abuse is seen in 25% to 40% of patients admitted to hospitals for general treatment. Many patients with substance use disorders have a higher risk for adverse events; however, only a small percentage will volunteer information regarding prior substance use. This article discusses the present opioid crisis, mechanisms behind chronic pain and substance abuse, current clinical findings, treatment therapies, and abuse deterrents.

Implementing a Postoperative Opioid-Prescribing Protocol Significantly Reduces the Total Morphine Milligram Equivalents Prescribed

BACKGROUND

Opioid-prescribing patterns have been implicated as a contributing factor to the opioid epidemic, yet few evidence-based guidelines exist to assist health-care providers in assessing and possibly modifying their prescribing practices.

METHODS

Five orthopaedic hand surgeons at a level-I trauma center developed a postoperative prescribing guideline for 25 common hand and upper-extremity outpatient procedures, which were delineated into 5 tiers. Postoperative opioid prescriptions in a 3-month period after implementation of the protocol were compared with those from a 3-month period before implementation of the protocol.

RESULTS

There were 231 patients in the pre-implementation group and 287 patients in the post-implementation group. Each individual opioid protocol tier showed a significant decrease in the mean morphine milligram equivalents (MME) prescribed, ranging from a minimum decrease of 97.8% to a maximum decrease of 176.0%. After implementation, adherence to protocol was achieved in 55.1% of patients; the MME amounts prescribed were below protocol for 28.6% and above for 16.4%. The number of additional opioid prescriptions in the 1-month postoperative period was significantly less in the post-implementation group than in the pre-implementation group (p < 0.001). The total number of pills prescribed was reduced by a theoretical equivalent of over three thousand 5-mg oxycodone pills for the 287 patients in the 3-month period.

CONCLUSIONS

By utilizing a simple consensus protocol, we have demonstrated success diminishing the number of opioids prescribed without leading to an increase in the number of secondary prescriptions written by our providers. These findings are encouraging and suggest that fewer opioids were left in the possession of patients, leaving fewer pills vulnerable to misuse, abuse, and diversion.

Evaluation of the Relative Intranasal Abuse Potential of a Hydrocodone Extended-Release Tablet Formulated with Abuse-Deterrence Technology in Nondependent, Recreational Opioid Users

Objective

To assess the intranasal abuse potential of hydrocodone extended-release (ER) tablets developed with CIMA Abuse-Deterrence Technology compared with hydrocodone powder and hydrocodone bitartrate ER capsules (Zohydro ER, original formulation [HYD-OF]).

Design

Single-dose, randomized, double-blind, quadruple-dummy, active- and placebo-controlled, crossover study.

Setting

One US site.

Subjects

Healthy, adult, nondependent, recreational opioid users.

Methods

Subjects able to tolerate intranasal hydrocodone and discriminate hydrocodone from placebo were eligible for study enrollment. Eligible participants randomly received intranasal hydrocodone ER, intranasal hydrocodone powder, intranasal HYD-OF, intact oral hydrocodone ER, and placebo. Coprimary pharmacodynamic end points were a maximum effect on “at the moment” Drug Liking visual analog scale and Overall Drug Liking visual analog scale. Pharmacokinetics and safety were assessed.

Results

Mean maximum effect for “at the moment” Drug Liking was significantly (P < 0.01) lower for intranasal hydrocodone ER (72.8) compared with hydrocodone powder (80.2) and HYD-OF (83.2). Similar results were observed for Overall Drug Liking maximum effect (68.5 vs 77.1 and 79.8, respectively; P < 0.01). Secondary end points, including balance of effects and positive, sedative, and other effects, were consistent with these results. Intranasal treatments showed significantly greater effects vs placebo, while intact oral hydrocodone ER was similar to placebo. For each treatment, plasma concentration-time profiles paralleled “at the moment” Drug Liking over time. Incidences of adverse events for intranasal treatments were 52% for hydrocodone ER, 53% for hydrocodone powder, and 61% for HYD-OF.

Conclusions

The statistically significant differences between hydrocodone ER vs hydrocodone powder and HYD-OF for the primary drug liking end points indicate a lower intranasal abuse potential with hydrocodone ER in healthy, nondependent, recreational opioid users.

Variation of Opioid Prescribing Patterns among Patients undergoing Similar Surgery on the Same Acute Care Surgery Service of the Same Institution: Time for Standardization?

BACKGROUND

Diversion of unused prescription opioids is a major contributor to the current United States opioid epidemic. We aimed to study the variation of opioid prescribing in emergency surgery.

METHODS

Between October 2016 and March 2017, all patients undergoing laparoscopic appendectomy, laparoscopic cholecystectomy, or inguinal hernia repair in the acute care surgery service of 1 academic center were included. For each patient, we systematically reviewed the electronic medical record and the prescribing pharmacy platform to identify: (1) history of opioid abuse, (2) opioid intake 3 months preoperatively, (3) number of opioid pills prescribed, (4) prescription of nonopioid pain medications (eg, acetaminophen, ibuprofen), and (5) the need for opioid prescription refills. The mean and range of opioid pills prescribed, as well as their oral morphine equivalent, were calculated.

RESULTS

A total of 255 patients were included (43.5% laparoscopic appendectomy, 44.3% laparoscopic cholecystectomy, and 12.1% inguinal hernia repair). The mean age was 47.5 years, 52.1% were female, 11.4% had a history of opioid use, and 92.5% received opioid prescriptions upon hospital discharge. Only 70.9% of patients were instructed to use nonopioid pain medications. The mean and range of opioid pills prescribed were 17.4; 0-56 (laparoscopic appendectomy), 17.1; 0-75 (laparoscopic cholecystectomy), and 20.9; 0-50 (inguinal hernia repair), while the range of prescribed oral morphine equivalent was 0-600 mg for laparoscopic appendectomy/laparoscopic cholecystectomy and 0-375 mg for inguinal hernia repair. No patients required any opioid medication refills.

CONCLUSION

Even within the same surgical service, wide variation of opioid prescription was observed. Guidelines that standardize pain management may help prevent opioid overprescribing.

An overview of abuse-deterrent opioids and recommendations for practical patient care

Despite advances in the treatment of severe intractable pain, opioids remain a critical and appropriate component of treatment. However, abuse, misuse, and diversion of prescription opioids are significant public health concerns. Opioid abuse-deterrent formulations (ADFs) are one component of an opioid risk management plan to manage patient’s pain relief and quality of life while offering some protection against potentially harmful consequences of opioids from misuse and abuse. Opioid ADFs are designed to make manipulation more difficult and administration via non-oral routes less appealing. There are currently nine extended-release and one immediate-release opioid pain medications with US Food and Drug Administration-approved ADF labeling. All use physical/chemical barriers or agonist/antagonist combinations to deter manipulation and abuse. Evidence suggests that opioid ADFs decrease rates of abuse and diversion of opioids in the USA; however, some opioid ADFs are not yet commercially available or have not been on the market long enough to undergo post-marketing data analyses. Opioid ADFs along with the use of prescription drug monitoring programs, clinical assessment tools, toxicology testing, and co-prescribing of naloxone are all tools that can be used to reduce opioid abuse. Patient education on the risks of abuse and diversion is vital and includes a discussion of appropriate use of medication and proper storage. Physician assistants and nurse practitioners are on the “front lines” in battling opioid abuse and serve a key role in recognizing and mitigating the risks of prescription opioid diversion, abuse, and misuse (intentional and unintentional) and in identifying patients at risk for abuse while still providing pain relief to patients.

Intranasal Pharmacokinetics of Morphine ARER, a Novel Abuse-Deterrent Formulation: Results from a Randomized, Double-Blind, Four-Way Crossover Study in Nondependent, Opioid-Experienced Subjects

Objective

To investigate the pharmacokinetics (PK) of Morphine ARER, an extended-release (ER), abuse-deterrent formulation of morphine sulfate after oral and intranasal administration.

Methods

This randomized, double-blind, double-dummy, placebo-controlled, four-way crossover study assessed the PK of morphine and its active metabolite, M6G, from crushed intranasal Morphine ARER and intact oral Morphine ARER compared with crushed intranasal ER morphine following administration to nondependent, recreational opioid users. The correlation between morphine PK and the pharmacodynamic parameter of drug liking, a measure of abuse potential, was also evaluated.

Results

Mean maximum observed plasma concentration (C_max) for morphine was lower with crushed intranasal Morphine ARER (26.2 ng/mL) and intact oral Morphine ARER (18.6 ng/mL), compared with crushed intranasal ER morphine (49.5 ng/mL). The time to C_max (T_max) was the same for intact oral and crushed intranasal Morphine ARER (1.6 hours) and longer for crushed intranasal morphine ER (1.1 hours). Higher mean maximum morphine C_max, T_max, and abuse quotient (C_max/T_max) were positively correlated with maximum effect for drug liking (R² ≥ 0.9795).

Conclusion

These data suggest that Morphine ARER maintains its ER profile despite physical manipulation and intranasal administration, which may be predictive of a lower intranasal abuse potential compared with ER morphine.

Compulsive-Like Sufentanil Vapor Self-Administration in Rats

Opioid misuse is at historically high levels in the United States, with inhalation (ie, smoking and vaping) being one of the most common routes of consumption. We developed and validated a novel preclinical model of opioid self-administration by inhalation that does not require surgery and reliably produces somatic and motivational signs of dependence. Rats were trained to perform an operant response (nosepoke) to receive 10 s of vaporized sufentanil, a potent opioid, in 2 h daily sessions. Rats readily and concentration-dependently self-administered vaporized sufentanil. Rats exhibited a significant increase in responding for sufentanil when given the preferential μ-opioid receptor inverse agonist naloxone, suggesting the participation of μ-opioid receptors in the reinforcing properties of sufentanil vapor. Serum sufentanil concentrations significantly correlated with the number of sufentanil vapor deliveries. Rats that were given long access (LgA; 12 h/day) but not short access (ShA; 1 h/day) to vaporized sufentanil escalated their drug intake over time and exhibited both naloxone-precipitated somatic signs of opioid withdrawal and spontaneous withdrawal-induced mechanical hypersensitivity. After 6 months of forced drug abstinence, LgA rats returned to pre-escalation baseline levels of responding for sufentanil and mechanical sensitivity. Upon subsequent re-escalation (ie, after the return to extended access to sufentanil vapor), LgA rats again developed naloxone-precipitated somatic signs of withdrawal and spontaneous withdrawal-induced mechanical hypersensitivity. These findings demonstrate that the operant sufentanil vapor self-administration model has both face and construct validity and therefore will be useful for investigating the neurobiological basis of opioid addiction.