Opioid Overdoses and Take-Home Naloxone Interventions: Ethnographic Evidence for Individual-Level Barriers to Treatment of Opioid Use Disorders in Rural Appalachia

Introduction: Research indicates that take-home naloxone (THN) is saving lives across rural Appalachia, but whether it also results in treatment for opioid use disorders (OUDs) remains unclear. This study involves a detailed qualitative analysis of interviews with 16 individuals who had overdosed on opioids 61 times to understand why a THN intervention does not routinely lead to OUD treatment. Methods: This study builds upon a one-year (2018) qualitative study on community responses to opioid overdose fatalities in four adjacent rural counties in Western Pennsylvania. Using a semi-structured interview guide, 16 individuals who had experienced one or more overdoses were interviewed. Using NVivo, the transcribed audio-recorded interviews were coded, and a thematic analysis of the coded text was conducted. Findings: Findings reveal that of the 29 overdoses that included a THN intervention, only eight resulted in treatment. The analysis derives five individual-level barriers to treatment: (1) opioid dependence, (2) denial/readiness, (3) opioid withdrawal fears, (4) incarceration concerns, and (5) stigma and shame. These barriers impeded treatment, even though all the interviewees knew of treatment programs, how to access them, and in some cases had undergone treatment previously. Discussion and Conclusion: findings indicate that there is evidence that the five barriers make entering treatment after a THN intervention challenging and seemingly insurmountable at times. Recommendations based on the findings include increasing efforts to reduce stigma of OUDs in the community, including self-stigma resulting from misusing opioids, increasing informational efforts about Good Samaritan Laws, and increasing familiarity with medication-assisted treatments for OUDS.

Changes in Buprenorphine Prescribing in Community Health Centers

This cohort study characterizes changes in buprenorphine prescribing among community health center clinicians between 2016 and 2021.

Emergency Department Take-Home Naloxone Improves Access Compared with Pharmacy-Dispensed Naloxone

BACKGROUND

Opioid overdose is a major cause of mortality in the United States. In spite of efforts to increase naloxone availability, distribution to high-risk populations remains a challenge.

OBJECTIVE

To assess the effects of multiple different naloxone distribution methods on patient obtainment of naloxone in the emergency department (ED) setting.

METHODS

Naloxone was provided to patients in three 12-month phases between February 2020 and February 2023. In Phase 1, physicians could offer patients electronic prescriptions, which were filled in a nearby in-hospital discharge pharmacy. In Phase 2, physicians directly provided patients with take-home naloxone at discharge. In Phase 3, distribution was expanded to allow ED staff to hand patients take-home naloxone at time of discharge. The total number of prescriptions, rate of prescription filling, and amount of take-home naloxone kits provided to patients were then statistically analyzed using 95% confidence intervals (CI) and chi-squared testing.

RESULTS

In Phase 1, 348 naloxone prescriptions were written, with 133 (95% CI 112.5-153.5) filled. In Phase 2, 327 (95% CI 245.5-408.5) take-home naloxone kits were given to patients by physicians. In Phase 3, 677 (95% CI 509.5-844.5) take-home naloxone kits were provided to patients by ED staff. There were statistically significant increases in naloxone distribution from Phase 1 to Phase 2, and Phase 2 to Phase 3.

CONCLUSIONS

Take-home naloxone increases access when compared with naloxone prescriptions in the ED setting. A multidisciplinary approach combined with the removal of regulatory and administrative barriers allowed for further increased distribution of no-cost naloxone to patients.

Associations Between Buprenorphine\Naloxone and Methadone Treatment and non-Opioid Substance Use in Prescription-Type Opioid Use Disorder: Secondary Analyses From the OPTIMA Study: Associations entre le traitement avec la buprénorphine/naloxone et avec la méthadone et l'utilisation de substances non opioïdes dans le trouble lié à l'usage d'opioïdes de type sur ordonnance : analyses secondaires de l'étude OPTIMA

OBJECTIVES

There is limited evidence on how opioid agonist treatment (OAT) may affect psychoactive non-opioid substance use in prescription-type opioid use disorder (POUD) and whether this effect might explain OAT outcomes. We aimed to assess the effect of methadone on non-opioid substance use compared to buprenorphine/naloxone (BUP/NX), to explore whether non-opioid substance use is associated with opioid use and retention in treatment, and to test non-opioid use as a moderator of associations between methadone with retention in OAT and opioid use compared to BUP/NX.

METHODS

This is a secondary analysis of data from the OPTIMA trial, an open-label, pragmatic, parallel, two-arm, pan-Canadian, multicentre, randomized-controlled trial to compare standard methadone model of care and flexible take-home dosing BUP/NX for POUD treatment. We studied the effect of methadone and BUP/NX on non-opioid substance use evaluated by urine drug screen (UDS) and by classes of non-opioid substances (i.e., tetrahydrocannabinol [THC], benzodiazepines, stimulants) (weeks 2-24) using adjusted generalized estimation equation (GEE). We studied the association between non-opioid substance-positive UDS and opioid-positive UDS and retention in treatment, using adjusted GEE and logistic regressions.

RESULTS

Overall, methadone was not associated with non-opioid substance-positive UDS compared to BUP/NX (OR: 0.78; 95%CI, 0.41 to 1.48). When non-opioid substances were studied separately, methadone was associated with lower odds of benzodiazepine-positive UDS (OR: 0.63; 95% CI: 0.40 to 0.98) and THC-positive UDS (OR: 0.47; 95% CI: 0.28 to 0.77), but not with different odds of stimulant-positive UDS (OR: 1.29; 95% CI: 0.78 to 2.16) compared to BUP/NX. Substance-positive UDS, overall and separate classes, were not associated with opioid-positive UDS or retention in treatment.

CONCLUSION

Methadone did not show a significant effect on overall non-opioid substance use in POUD compared to BUP/NX treatment but was associated with lower odds of benzodiazepine and THC use in particular. Non-opioid substance use did not predict OAT outcomes. Further research is needed to ascertain whether specific patterns of polysubstance use (quantity and frequency) may affect treatment outcomes.

Buprenorphine dispensing before and after the April 2021 X-Waiver exemptions: An interrupted time series analysis

BACKGROUND

Until the end of 2022, a special registration, known as the X-waiver, was required to prescribe buprenorphine in the US. Before its removal, US federal regulations trialed an X-waiver exemption, initiated on April 28, 2021, which permitted buprenorphine prescribing for up to 30 patients without additional training. We aimed to understand if these regulatory changes impacted buprenorphine dispensing.

METHODS

We conducted an interrupted time series analysis to understand changes in buprenorphine dispensing during the 26 weeks after the X-waiver exemption compared to the expected baseline trend established in the 26 weeks before using the IQVIA Longitudinal Prescription claims database. The primary outcome was number of new buprenorphine prescribers nationwide (defined as no prior buprenorphine prescription dispensed in the last 26 weeks). Segmented regression estimated relative changes in buprenorphine dispensing at 1, 13, and 26 weeks post-X-waiver change.

RESULTS

A total of 15,517,525 prescriptions filled for 1,328,172 patients (43.4 % female) ordered by 62,312 providers were included for analysis. At 26 weeks post-X-waiver change, there was no change in the number of new prescribers compared to the expected baseline trend (-2.7 % [95 % CI:-8.3,2.9]). The number of new (15.2 % [4.6,25.8]) and existing (1.7 % [0.9,2.4]) patients and patients per prescriber (4.3 % [3,5.6]) increased. Buprenorphine prescriptions reimbursed by Medicaid increased (7.5 % [6.6,8.4]) while commercial fills decreased (-3.4 % [-5.3,-1.5]).

CONCLUSIONS

The number of new prescribers did not increase six months post-X-waiver exemption while new patients continued to enter treatment at higher-than-expected rates. These findings suggest that additional interventions beyond the recent X-waiver removal may be needed to increase access to buprenorphine.

The Management of Opioid-Induced Constipation in Cancer and Advanced Illness: A Meta-Analysis

CONTEXT

Constipation is a common problem among patients with cancer. By some accounts, about 60% of cancer patients experience constipation. There is limited empirical evidence of the clinical effectiveness of pharmacologic agents in opioid-induced constipation in advanced diseases.

OBJECTIVES

We sought to quantitatively summarize the therapeutic effectiveness of the pharmacologic means of managing opioid-induced constipation.

METHODS

Randomized control trials (RCTs) identified from medical literature databases that reported quantitative measures of the effect of pharmacotherapeutic agents to treat opioid induced constipation in patients with cancers and other advanced illnesses were included in this study. A conventional random effects meta-analysis was conducted including >3 trials with the same exposure and outcome assessed, and a network-meta-analysis was conducted for all placebo-controlled trials.

RESULTS

Eighteen studies that examined the effect of various pharmacotherapeutic agents were included. The medications were Methylnatrexone (N = 5), Naldemedine (N = 5), other conventional agents (N = 4) and herbal medicines (N = 4). In conventional meta-analysis, methylnaltrexone increased the proportion achieving rescue-free laxation by 2.68 fold (95% CI: 1.34, 5.37; P = 0.0054) within 4 hours of the administration compared to placebo. In network meta-analysis, the pooled RR of the pharmacotherapeutic agents on rescue-free bowel movements as 2.26 (95% CI: 1.52, 3.36) for methylnaltrexone, 1.58 (95% CI: 0.94, 2.66) for naldemedine, and 0.74 (95% CI: 0.45, 1.23) for polyethylene glycol, compared to placebo.

CONCLUSION

Methylnatrexone and Naldemedine have currently shown promise in randomized trials concerning opioid-induced constipation in cancer and advanced illness. It is imperative that future research ascertain not just the relative therapeutic efficacy but also the cost-benefit analyses of these newer regimens with more commonly used and accessible laxatives.

Simplified processing and rapid quantification of buprenorphine, norbuprenorphine, and their conjugated metabolites in human plasma using UPLC-MS/MS: Assessment of buprenorphine exposure during opioid use disorder treatment

Opioid use disorder (OUD) is a chronic neurobehavioral ailment and is prevalent in pregnancy. OUD is commonly treated with methadone or buprenorphine (BUP). Pregnancy is known to alter the pharmacokinetics of drugs and may lead to changes in drug exposure and response. A simple, specific, and sensitive analytical method for measuring the parent drug and its metabolites is valuable for assessing the impact of pregnancy on drug exposure. A new liquid chromatography-tandem mass spectrometric method that utilized a simple protein precipitation procedure for sample preparation and four deuterated internal standards for quantification was developed and validated for BUP and its major metabolites (norbuprenorphine [NBUP], buprenorphine-glucuronide [BUP-G], and norbuprenorphine-glucuronide [NBUP-G]) in human plasma. The standard curve was linear over the concentration range of 0.05-100 ng/mL for BUP and NBUP, and 0.1-200 ng/mL for BUP-G and NBUP-G. Intra- and inter-day bias and precision were within ±15% of nominal values for all the analytes. Quality controls assessed at four levels showed high recovery consistently for all the analytes with minimal matrix effect. Adequate analyte stability was observed at various laboratory conditions tested. Overall, the developed method is simple, sensitive, accurate and reproducible, and was successfully applied for the quantification of BUP and its metabolites in plasma samples collected from pregnant women in a clinical study assessing BUP exposure during OUD treatment.

A Wearable Device Towards Automatic Detection and Treatment of Opioid Overdose

Opioid-induced overdose is one of the leading causes of death among the US population under the age of 50. In 2021 alone, the death toll among opioid users rose to a devastating number of over 80,000. The overdose process can be reversed by the administration of naloxone, an opioid antagonist that rapidly counteracts the effects of opioid-induced respiratory depression. The idea of a closed-loop opioid overdose detection and naloxone delivery has emerged as a potential engineered solution to mitigate the deadly effects of the opioid epidemic. In this work, we introduce a wrist-worn wearable device that overcomes the portability issues of our previous work to create a closed-loop drug-delivery system, which includes (1) a Near-Infrared Spectroscopy (NIRS) sensor to detect a hypoxia-driven opioid overdose event, (2) a MOSFET switch, and (3) a Zero-Voltage Switching (ZVS) electromagnetic heater. Using brachial artery occlusion (BAO) with human subjects (n = 8), we demonstrated consistent low oxygenation events. Furthermore, we proved our device's capability to release the drug within 10 s after detecting a hypoxic event. We found that the changes in the oxyhemoglobin, deoxyhemoglobin and oxygenation saturation levels ( SpO2) were different before and after the low-oxygenation events ( 0.001). Although additional human experiments are needed, our results to date point towards a potential tool in the battle to mitigate the effects of the opioid epidemic.

Attitudes toward extended-release naltrexone treatment for opioid use disorder among African Americans

BACKGROUND

Extended-release naltrexone (XR-NTX; Vivitrol®) is a long-acting injectable form of naltrexone, which is a medication used to treat opioid use disorder (OUD). In 2010, XR-NTX received Food and Drug Administration approval to treat OUD, becoming the first non-addictive and non-psychoactive medication for this condition. Because uptake of XR-NTX has been relatively low, less is known regarding how persons with OUD view this form of treatment. And because previous studies tend to rely on samples that lack racial diversity or are conducted outside the United States, we know very little about how African Americans view XR-NTX. The objective of this study, therefore, was to identify/explain the most salient attitudes toward XR-NTX as a form of OUD treatment among African Americans.

METHODS

In-depth interviews (n = 30) were conducted with a sample of African American adults who used opioids in Southwest Florida between August 2021 and February 2022. Audiotapes of interviews were transcribed, coded, and thematically analyzed.

RESULTS

Analyses revealed that participants' attitudes toward XR-NTX were generally positive. Specifically, participants found XR-NTX's monthly injection administration, non-addictive and non-intoxicating properties, and perceived effectiveness (compared to other medications for OUD) most appealing.

CONCLUSIONS

Study findings suggest that African Americans who use opioids may have more favorable attitudes toward XR-NTX than other medications for OUD (e.g., methadone), which tend to be highly stigmatized. These data uniquely contribute to the literature by capturing the voices of African Americans who use opioids, a group with high rates of opioid-related deaths.

Pharmacological prevention and treatment of opioid-induced constipation in cancer patients: A systematic review and meta-analysis

BACKGROUND

Cancer-related pain often requires opioid treatment with opioid-induced constipation (OIC) as its most frequent gastrointestinal side-effect. Both for prevention and treatment of OIC osmotic (e.g. polyethylene glycol) and stimulant (e.g. bisacodyl) laxatives are widely used. Newer drugs such as the peripherally acting µ-opioid receptor antagonists (PAMORAs) and naloxone in a fixed combination with oxycodone have become available for the management of OIC. This systematic review and meta-analysis aims to give an overview of the scientific evidence on pharmacological strategies for the prevention and treatment of OIC in cancer patients.

METHODS

A systematic search in PubMed, Embase, Web of Science and the Cochrane Library was completed from inception up to 22 October 2022. Randomized and non-randomized studies were systematically selected. Bowel function and adverse drug events were assessed.

RESULTS

Twenty trials (prevention: five RCTs and three cohort studies; treatment: ten RCTs and two comparative cohort studies) were included in the review. Regarding the prevention of OIC, three RCTs compared laxatives with other laxatives, finding no clear differences in effectivity of the laxatives used. One cohort study showed a significant benefit of magnesium oxide compared with no laxative. One RCT found a significant benefit for the PAMORA naldemedine compared with magnesium oxide. Preventive use of oxycodone/naloxone did not show a significant difference in two out of three other studies compared to oxycodone or fentanyl. A meta-analysis was not possible. Regarding the treatment of OIC, two RCTs compared laxatives, of which one RCT found that polyethylene glycol was significantly more effective than sennosides. Seven studies compared an opioid antagonist (naloxone, methylnaltrexone or naldemedine) with placebo and three studies compared different dosages of opioid antagonists. These studies with opioid antagonists were used for the meta-analysis. Oxycodone/naloxone showed a significant improvement in Bowel Function Index compared to oxycodone with laxatives (MD -13.68; 95 % CI -18.38 to -8.98; I2 = 58 %). Adverse drug event rates were similar amongst both groups, except for nausea in favour of oxycodone/naloxone (RR 0.51; 95 % CI 0.31-0.83; I2 = 0 %). Naldemedine (NAL) and methylnaltrexone (MNTX) demonstrated significantly higher response rates compared to placebo (NAL: RR 2.07, 95 % CI 1.64-2.61, I2 = 0 %; MNTX: RR 3.83, 95 % CI 2.81-5.22, I2 = 0 %). With regard to adverse events, abdominal pain was more present in treatment with methylnaltrexone and diarrhea was significantly more present in treatment with naldemedine. Different dosages of methylnaltrexone were not significantly different with regard to both efficacy and adverse drug event rates.

CONCLUSIONS

Magnesium oxide and naldemedine are most likely effective for prevention of OIC in cancer patients. Naloxone in a fixed combination with oxycodone, naldemedine and methylnaltrexone effectively treat OIC in cancer patients with acceptable adverse events. However, their effect has not been compared to standard (osmotic and stimulant) laxatives. More studies comparing standard laxatives with each other and with opioid antagonists are necessary before recommendations for clinical practice can be made.

Pharmacological management of gambling disorder: an update of the literature

INTRODUCTION

Gambling disorder (GD) is a mental health condition characterized by persistent and problematic betting behavior. GD generates distress and impairment, and treatment options include psychological and pharmacological interventions.

AREAS COVERED

This narrative review explores existing pharmacological treatments for GD. The following classes of medications were considered: opioid-receptor antagonists (e.g. naltrexone and nalmefene), serotonin reuptake inhibitors (e.g. fluvoxamine, paroxetine, sertraline, escitalopram, and citalopram), glutamatergic agents (e.g. N-acetylcysteine (NAC), acamprosate, and memantine), mood stabilizers (e.g. topiramate, carbamazepine, lithium), and other medications (e.g. modafinil, nefazodone, olanzapine, haloperidol, tolcapone, and bupropion).

EXPERT OPINION

Due to the limitations of the studies reviewed, solid conclusions regarding the optimal choice of pharmacotherapy for individuals with GD are challenging to draw at this time. Despite some medications, such as naltrexone and nalmefene, showing promising results, efficacy has varied across studies. The review highlights current gaps/limitations, including small sample sizes, limited diversity in participant demographics, the need for exploring different gambling subtypes and treatment responses, high placebo response rates, lack of longer-term longitudinal information, limited investigation of neurobiological correlates and co-occurring disorders, and the importance of implementation research. Further research is needed to address these gaps and explore additional medications, as well as interventions like neuromodulation.

Evaluation of the Impact of Pharmacist-Driven Physician Naloxone Training on an Inpatient Psychiatric Unit

OBJECTIVES

The purpose of this study was to evaluate the impact of pharmacist-driven naloxone training of resident physicians as part of discharge prescribing from an inpatient psychiatric unit.

METHODS

This is a prospective pilot study in which psychiatric resident physicians (N = 21) were educated on naloxone administration, prescribing, and counseling. A ten-question survey was designed and delivered immediately pre- and post-training to assess resident knowledge of and comfort with naloxone prescribing. Respondents were asked to rate ten statements on a scale from 1 to 5, with 1 corresponding to "strongly disagree" and 5 corresponding to "strongly agree." The primary objective was to evaluate the impact of training on prescriber knowledge and attitudes using the designed questionnaire. The secondary objective was to assess the difference in naloxone prescribing pre- and post-training implementation. Descriptive statistics and paired t-tests were conducted to assess statistical significance.

RESULTS

Prior to training, 11 resident physicians (approximately 50%) agreed or strongly agreed that they felt knowledgeable about naloxone and approximately 70% (n = 15) felt confident identifying patients who would benefit from naloxone at discharge. Only 10% of resident physicians (n = 2) felt comfortable counseling patients on and administering naloxone during an overdose pre-training compared to 100% after training. Thirty-seven patients were discharged and counseled on naloxone use during the study period.

CONCLUSION

Pharmacist-driven naloxone training significantly increased physician knowledge and comfort prescribing naloxone and resulted in an increase in naloxone prescriptions upon discharge from an inpatient psychiatric unit.

Predictive Factors Associated with Naloxone Prescription among Pregnant People Admitted for the Management of Opioid Use Disorder

OBJECTIVE

 Our objective was to examine the biomedical and sociodemographic factors associated with the prescription of naloxone among pregnant people with opioid-use disorder (OUD) who were admitted for initiation of medications for OUD (i.e., buprenorphine-containing medications or methadone) following the implementation of a statewide initiative focused on reducing adverse perinatal health outcomes.

STUDY DESIGN

 This is a single-site, retrospective cohort study of pregnant people admitted for the management of OUD at an urban, tertiary care center between 2013 and 2020. The primary outcome is evidence of a prescription of naloxone, ascertained from the electronic medical record. Bivariate and multivariable logistic regression modeling was performed to evaluate biomedical and sociodemographic variables associated with a prescription for naloxone. Covariates for inclusion in the multivariate logistic regression model were selected based on a p < 0.05 on bivariate analysis. Statistical significance was set at p < 0.05.

RESULTS

 One hundred and thirty-nine participants met the inclusion criteria. On bivariate analysis, people who received naloxone were more likely to be admitted after the initiation of a statewide initiative focused on reducing adverse perinatal outcomes associated with perinatal OUD. Those individuals reporting intravenous drug use (IVDU) were less likely to receive naloxone. On multivariate logistic regression, after controlling for IVDU and epoch of admission, both IVDU (adjusted odds ratio [aOR]: 0.27, 95% confidence interval [CI]: 0.11-0.70) and epoch of admission (aOR: 3.48, 95% CI: 1.28-9.50) were independently associated with receipt of prescription of take-home naloxone.

CONCLUSION

 Naloxone prescription was independently associated with the epoch of admission and route of drug administration. These data can be useful in the evaluation and development of clinical practices to increase rates of naloxone prescription in pregnant people with OUD admitted for inpatient management.

KEY POINTS

· Thirty four percent of individuals with perinatal OUD were prescribed take-home naloxone (THN).. · Epoch of admission and route of drug administration were independently associated with THN.. · These data can be used to guide public health and clinical programming for pregnant people..

Adverse Effects After Prehospital Administration of Naloxone by Bystanders: A Preliminary Study

OBJECTIVE

Opioid use disorder is a cause of significant morbidity and mortality. In order to reverse opioid overdose as quickly as possible, many institutions and municipalities have encouraged people with no professional medical training to carry and administer naloxone. This study sought to provide preliminary data for research into the rates of adverse effects of naloxone when administered by bystanders compared to Emergency Medical Services (EMS) personnel, since this question has not been studied previously.

METHODS

This was a retrospective cohort study performed at an urban, tertiary, academic medical center that operates its own EMS service. A consecutive sample of patients presenting to EMS with opioid overdose requiring naloxone was separated into two groups based on whether naloxone was administered by bystanders or by EMS personnel. Each group was analyzed to determine the incidence of four pre-specified adverse events.

RESULTS

There was no significant difference in the rate of adverse events between the bystander (19%) and EMS (16%) groups (OR = 1.23; 95% CI, 0.63 - 2.32; P = .499) in this small sample. Based on these initial results, a study would need a sample size of 6,188 in order to reach this conclusion with 80% power. Similarly, there were no significant differences in the rates of any of the individual adverse events. Secondary analysis of patients' demographics showed differences between the two groups which generate hypotheses for further investigation of disparities in naloxone administration.

CONCLUSIONS

This preliminary study provides foundational data for further investigation of naloxone administration by bystanders. Adverse events after the prehospital administration of naloxone are rare, and future studies will require large sample sizes. These preliminary data did not demonstrate a statistically significant difference in adverse event rates when comparing naloxone administration by bystanders and EMS clinicians. This study provides data that will be useful for conducting further research on multiple facets of this topic.

Developing medical simulations for opioid overdose response training: A qualitative analysis of narratives from responders to overdoses

Medical simulation offers a controlled environment for studying challenging clinical care situations that are difficult to observe directly. Overdose education and naloxone distribution (OEND) programs aim to train potential rescuers in responding to opioid overdoses, but assessing rescuer performance in real-life situations before emergency medical services arrive is exceedingly complex. There is an opportunity to incorporate individuals with firsthand experience in treating out-of-hospital overdoses into the development of simulation scenarios. Realistic overdose simulations could provide OEND programs with valuable tools to effectively teach hands-on skills and support context-sensitive training regimens. In this research, semi-structured interviews were conducted with 17 individuals experienced in responding to opioid overdoses including emergency department physicians, first responders, OEND program instructors, and peer recovery specialists. Two coders conducted qualitative content analysis using open and axial thematic coding to identify nuances associated with illicit and prescription opioid overdoses. The results are presented as narrative findings complemented by summaries of the frequency of themes across the interviews. Over 20 hours of audio recording were transcribed verbatim and then coded. During the open and axial thematic coding process several primary themes, along with subthemes, were identified, highlighting the distinctions between illicit and prescription opioid overdoses. Distinct contextual details, such as locations, clinical presentations, the environment surrounding the patient, and bystanders' behavior, were used to create four example simulations of out-of-hospital overdoses. The narrative findings in this qualitative study offer context-sensitive information for developing out-of-hospital overdose scenarios applicable to simulation training. These insights can serve as a valuable resource, aiding instructors and researchers in systematically creating evidence-based scenarios for both training and research purposes.

LY2444296, a κ-opioid receptor antagonist, selectively reduces alcohol drinking in male and female Wistar rats with a history of alcohol dependence

Alcohol use disorder (AUD) remains a major public health concern. The dynorphin (DYN)/κ-opioid receptor (KOP) system is involved in actions of alcohol, particularly its withdrawal-associated negative affective states. This study tested the ability of LY2444296, a selective, short-acting, KOP antagonist, to decrease alcohol self-administration in dependent male and female Wistar rats at 8 h abstinence. Animals were trained to orally self-administer 10% alcohol (30 min/day for 21 sessions) and were made dependent via chronic intermittent alcohol vapor exposure for 6 weeks or exposed to air (nondependent). After 6 weeks, the effect of LY2444296 (0, 3, and 10 mg/kg, p.o.) was tested on alcohol self-administration at 8 h of abstinence. A separate cohort of rats was prepared in parallel, and their somatic withdrawal signs and alcohol self-administration were measured after LY2444296 administration at 8 h, 2 weeks, and 4 weeks abstinence. LY2444296 at 3 and 10 mg/kg significantly reduced physical signs of withdrawal in dependent rats at 8 h abstinence, only. Furthermore, 3 and 10 mg/kg selectively decreased alcohol self-administration in dependent rats at only 8 h abstinence. These results highlight the DYN/KOP system in actions of alcohol during acute abstinence, suggesting KOP antagonism could be beneficial for mitigating acute withdrawal signs and, in turn, significantly reduce excessive alcohol consumption associated with AUD.

Clinical Implications of the Relationship Between Naltrexone Plasma Levels and the Subjective Effects of Heroin in Humans

BACKGROUND

Extended-release naltrexone (NTX) is an opioid antagonist approved for relapse prevention after medical withdrawal. Its therapeutic effect is dependent on the NTX plasma level, and as it decreases, patients may lack protection against relapse and overdose. Therefore, identifying the minimally effective NTX level needed to block opioid-induced subjective effects has important clinical implications.

METHODS

This secondary, individual-level analysis of data collected in a human laboratory study was conducted to evaluate the relationship between NTX levels and subjective effects of an intravenously administered 25-mg challenge dose of heroin in non-treatment-seeking participants with opioid use disorder (N = 12). Subjective ratings of drug liking using a 100-mm visual analog scale (VAS) and NTX levels were measured across 6 weeks after participants received a single injection of either extended-release NTX 192 mg (N = 6) or 384 mg (N = 6). Cubic spline mixed-effects models were used to provide 95% prediction intervals for individual changes in liking scores as a function of NTX levels.

RESULTS

Naltrexone levels above 2 ng/mL blocked nearly all VAS ratings of drug liking after intravenous heroin administration. Participants with NTX levels ≥ 2 ng/mL had minimal (≤20 mm) changes from placebo in VAS ratings of drug liking based on 95% prediction intervals. In contrast, NTX levels < 2 ng/mL were associated with greater variability in individual-level subjective responses.

CONCLUSIONS

In clinical practice, a plasma level range of 1 to 2 ng/mL is considered to be therapeutic in providing heroin blockade. The current findings suggest that a higher level (>2 ng/mL) may be needed to produce a consistent blockade.