The role of opioidergic system in modulating cost/benefit decision-making in alcohol-preferring AA rats and Wistar rats.

Research has highlighted the association of a positive family history of alcoholism with a positive treatment response to opioid antagonists in those with a gambling disorder. However, the role of the opioidergic system in gambling behavior is not well understood, and preclinical studies are needed to clarify this. In this study, Alko Alcohol (AA) and Wistar rats went through operant lever pressing training where the task was to choose the more profitable of two options. Different sized sucrose rewards guided the lever choices, and the probability of gaining rewards changed slowly to a level where choosing the smaller reward was the most profitable option. After training, rats were administered subcutaneously with opioid agonist morphine or opioid antagonist naltrexone to study the impact of opioidergic mechanisms on cost/benefit decisions. No difference was found in the decision-making between AA rats or Wistar rats after the morphine administration, but control data revealed a minor decision enhancing effect in AA rats. Naltrexone had no impact on the decisions in AA rats but promoted unprofitable decisions in Wistar rats. Supporting behavioral data showed that in both rat strains morphine increased, and naltrexone decreased, sucrose consumption. Naltrexone also increased the time to accomplish the operant task. The results suggest that opioid agonists could improve decision-making in cost-benefit settings in rats that are naturally prone to high alcohol drinking. The naltrexone results are ambiguous but may partly explain why opioid antagonists lack a positive pharmacotherapeutic effect in some subgroups of gamblers.

Receipt of training about medication for opioid use disorder from pharmaceutical manufacturers: A preliminary study of Florida criminal problem-solving and dependency court staff.

INTRODUCTION AND AIMS: People with opioid use disorder are prevalent in criminal problem-solving courts and dependency courts, which have rehabilitative aims. Medication for opioid use disorder (MOUD) is the standard of care. Court staff set treatment policies for court clients. They may receive training from MOUD manufacturers, but no studies have examined court staff receipt of such training. DESIGN AND METHODS: To examine receipt of training from MOUD manufacturers, we designed a cross-sectional survey for court staff. We distributed it online to all Florida court staff in criminal problem-solving or dependency courts (n = 585). Outcome variables were receipt of training from one or more MOUD manufacturers and training source. Covariates included dichotomous measures of court type, staff role, gender and rurality. Logistic regression models estimated the relationship between receipt of training and covariates. RESULTS: Twenty-one percent of Florida criminal problem-solving and dependency court staff completed the survey. The most common receipt of training was from the manufacturer of extended-release naltrexone (36%), followed by buprenorphine (24%) and methadone (11%). Fifty-seven percent of those who received training received it from more than one MOUD manufacturer. Criminal problem-solving court staff were more likely than dependency court staff to receive training from MOUD manufacturers. Court program co-ordinators were more likely than other staff roles to receive training from MOUD manufacturers. DISCUSSION AND CONCLUSIONS: A large minority of respondents received training from a MOUD manufacturer, primarily from extended-release naltrexone's manufacturer, raising concerns regarding information accuracy and conflicts of interest. Court staff should seek MOUD training from academic institutions and non-profit organisations instead.

Impact of Pharmacological Treatments for Opioid Use Disorder on Mortality.

The use of pharmacological treatments for opioid use disorders, including methadone, buprenorphine and naltrexone has been associated with a reduction in mortality compared with illicit opioid use. However, these treatments can also contribute significantly to the risk of death. The opioid agonists methadone and buprenorphine achieve clinical efficacy in patients with an opioid use disorder through suppressing craving and diminishing the effectiveness of illicit opioid doses, while the antagonist naltrexone blocks the action of opioids. Pharmacological differences between opioid pharmacotherapies then create different temporal patterns of protection and mortality risk, different risks of relapse to illicit opioid use, and variations in direct and indirect toxicity, which are revealed in clinical and epidemiological studies. Induction onto methadone and the cessation of oral naltrexone treatment are associated with an elevated risk of opioid poisoning, which is not apparent in patients treated with buprenorphine or sustained-release naltrexone. Beyond drug-related mortality, these pharmacotherapies can impact a participant's risk of death. Buprenorphine may also have some advantages over methadone in patients with depressive disorders or cardiovascular abnormalities. Naltrexone, which is also commonly prescribed to manage problem alcohol use, may reduce deaths in chronic co-alcohol users. Understanding these pharmacologically driven patterns then guides the judicious choice of drug and dosing schedule and the proactive risk management that is crucial to minimising the risk of death in treatment.

Overdose following initiation of naltrexone and buprenorphine medication treatment for opioid use disorder in a United States commercially insured cohort.

BACKGROUND AND AIMS: Despite the growing opioid overdose crisis, medication treatment for opioid use disorder remains uncommon. The comparative effectiveness of buprenorphine and naltrexone treatment in reducing overdose and the comparative risks of discontinuing treatment in the real world, remain uncertain. Our aim was to examine the effectiveness of medications for opioid use disorder in preventing opioid-related overdose. DESIGN: Retrospective cohort study SETTING: United States. PATIENTS: 46,846 commercially insured individuals diagnosed with opioid use disorder and initiating medication treatment between 2010 and 2016. MEASUREMENTS: Opioid-related overdose identified by International Classification of Diseases, Ninth and Tenth Revisions. FINDINGS: In our sample, 1386 individuals were prescribed extended-release injectable naltrexone (median filled prescriptions = 9 months), 7782 were prescribed oral naltrexone (5 months), and 40,441 were prescribed buprenorphine (19 months) at least once during follow-up. Individuals receiving buprenorphine therapy were at significantly reduced risk of opioid-related overdose compared to no treatment (adjusted hazard ratio (HR) = 0.40, 95% CI 0.35-0.46), while a significant association was not observed in extended-release injectable (HR = 0.74, 95% CI 0.42-1.31) or oral (HR = 0.93, 95% CI 0.71-1.22) naltrexone. We found no association with opioid overdose within four weeks of discontinuation of any medication. CONCLUSION: Among commercially-insured patients who initiate medications for opioid use disorder, buprenorphine, but not naltrexone, was associated with lower risk of overdose during active treatment compared to post-discontinuation. More research is needed to understand the benefits and risks unique to each treatment option to better tailor therapies to patients with opioid use disorder.

Extended-release vs. oral naltrexone for alcohol dependence treatment in primary care (XON).

BACKGROUND: Extended-release naltrexone (XR-NTX, Vivitrol®) and daily oral naltrexone tablets (O-NTX) are FDA-approved mu opioid receptor antagonist medications for alcohol dependence treatment. Despite the efficacy of O-NTX, non-adherence and poor treatment retention have limited its adoption into primary care. XR-NTX is a once-a-month injectable formulation that offers a potentially more effective treatment option in reducing alcohol consumption and heavy drinking episodes among persons with alcohol use disorders. METHODS: This pragmatic, open-label, randomized controlled trial examines the effectiveness of XR-NTX vs. O-NTX in producing a Good Clinical Outcome, defined as abstinence or moderate drinking (<2 drinks/day, men; <1 drink/day, women; and < 2 heavy drinking occasions/month) during the final 20 of 24 weeks of primary care-based Medical Management treatment for alcohol dependence. Secondary aims will estimate the cost effectiveness of XR-NTX vs. O-NTX, in conjunction with primary-care based Medical Management for both groups, and patient-level characteristics associated with effectiveness in both arms. Alcohol dependent persons are recruited from the community into treatment in a New York City public hospital primary care setting (Bellevue Hospital Center) for 24 weeks of either XR-NTX (n = 117) or O-NTX (n = 120). RESULTS: We describe the rationale, specific aims, design, and recruitment results to date. Alternative design considerations and secondary aims and outcomes are reported. CONCLUSIONS: XR-NTX treatment in a primary care setting is potentially more efficacious, feasible, and cost-effective than oral naltrexone when treating community-dwelling persons with alcohol use disorders. This study will estimate XR-NTX's treatment and cost effectiveness relative to oral naltrexone.

The Affordable Care Act In The Heart Of The Opioid Crisis: Evidence From West Virginia.

West Virginia is at the epicenter of a national opioid crisis, with a 2016 fatal opioid overdose rate of 43.4 per 100,000 population-more than triple the US average. We used claims data for 2014-16 to examine trends in treatment for opioid use disorder (OUD) among people enrolled in the West Virginia Medicaid expansion program under the Affordable Care Act. Expanding Medicaid could provide services to populations that may previously have had limited access to OUD treatment. We thus sought to understand trends over time in OUD diagnosis and treatment, especially with medications. About 5.5 percent of all enrollees were diagnosed with OUD per year, and the monthly prevalence of OUD diagnoses nearly tripled during this three-year period. The ratio of people filling buprenorphine to the number diagnosed with OUD was around one-third in early 2014, increasing to more than 75 percent by late 2016. Mean annual duration of filled buprenorphine increased from 161 days in 2014 to 185 days in 2016, and most people filling buprenorphine also received counseling and drug testing during the study period. The growing use of medication treatment for OUD in the West Virginia Medicaid expansion population provides an opportunity to reduce overdose deaths.

Real-world misuse, abuse, and dependence of abuse-deterrent versus non-abuse-deterrent extended-release morphine in Medicaid non-cancer patients.

OBJECTIVE: Opioids with abuse-deterrent properties may reduce widespread abuse, misuse, and diversion of these products. This study aimed to quantify misuse, abuse, dependence, and health resource use of extended-release morphine sulfate with sequestered naltrexone hydrochloride (ER-MSN; EMBEDA®), compared with non-abuse-deterrent extended-release morphine (ERM) products in Medicaid non-cancer patients. METHODS: Administrative medical and pharmacy claims data were analyzed for 10 Medicaid states from 1 January 2015, to 30 June 2016. Patients were included if they received a prescription for ER-MSN or any oral, non-abuse-deterrent ERM. Index date was the date of first prescription for an ER-MSN or ERM. Abuse/dependence, non-fatal overdose, emergency department (ED) visits, and ED/inpatient readmissions were determined for each participant. An overall measure of misuse and abuse was also calculated. To account for differences in follow-up, all counts are expressed per 100 patient-years. RESULTS: There were 4,857 patients who received ER-MSN and 10,357 who received an ERM. The average age in the two cohorts was approximately 45 years old. From pre-index to follow-up, the number of patients per 100 patient-years with a diagnosis code indicating abuse or dependence increased by 0.91 (95% confidence interval [CI]: 0.85, 0.97) in the ER-MSN cohort and 2.23 (95% CI: 2.14, 2.32) in the ERM cohort. The number of patients per 100 patient-years with an opioid-related non-fatal overdose increased by 0.05 (95% CI: 0.04, 0.06) in the ER-MSN cohort compared with 0.11 (95% CI: 0.09, 0.13) in the ERM cohort. The opioid abuse overall composite score increased by 1.36 (95% CI: 1.24, 1.48) in the post-index period in the ER-MSN cohort compared to 3.21 (95% CI: 3.10, 3.32) in the ERM cohort. CONCLUSION: Misuse, abuse, and dependence events were numerically lower in patients receiving ER-MSN compared with those receiving ERM products.

Extended-release naltrexone versus standard oral naltrexone versus placebo for opioid use disorder: the NEAT three-arm RCT.

BACKGROUND: People recovering from heroin addiction need better treatments than are currently offered. The chronic relapsing nature of drug dependence means that helping a patient to achieve abstinence is often difficult. Naltrexone blocks the effects of ingested heroin; however, evidence is conflicting regarding the best delivery method. OBJECTIVES: The primary purpose of the trial was to evaluate the clinical effectiveness and cost-effectiveness of extended-release naltrexone versus standard oral naltrexone versus relapse prevention therapy without medication for opioid use disorder (OUD). DESIGN: This was a 3-year, definitive, three-centre, three-arm, parallel group, placebo-controlled, double-blind, double-dummy, randomised controlled trial. SETTING: Two specialist NHS outpatient addiction clinics: one in London and one in Birmingham. PARTICIPANTS: Planned study sample - 300 adult patients with OUD who had completed detoxification. INTERVENTIONS: One iGen/Atral-Cipan Extended Release Naltrexone device (iGen/Atral-Cipan, Castanheira do Ribatejo, Portugal) (765 mg naltrexone or placebo) at day 0 of study week 1. Three weekly directly observed active or placebo oral naltrexone tablets (2 × 50 mg, Monday and Wednesday; 3 × 50 mg, Friday) at day 0 of study week 1 (for 4 weeks) and then an 8-week regimen of patient-administered dosing at the same dosing level. MAIN OUTCOME MEASURE: The primary outcome measure was the proportion of heroin-negative urine drug screen (UDS) results at the end of the 12-week post-randomisation time point. RESULTS: Six patients were recruited and randomised to receive study interventions. Two patients had no positive UDS samples for heroin during the 12-week treatment period, one patient had only one positive UDS sample and the remaining patients had two, six and eight positive UDS results for heroin. All patients had at least one missed clinic visit (range 1-14). CONCLUSIONS: Considerable problems were encountered with (1) the stipulated requirement of a validated 'detoxified' status prior to the initiation of the study naltrexone, (2) the requirement for a consent cooling-off period and (3) delays awaiting the surgical implant procedure. Major upheaval to the organisation and delivery of NHS community treatment services across England led to extremely poor levels of actual entry of patients into the trial. Research-vital clinical and procedural requirements were, therefore, more challenging to implement. The potential therapeutic value of the opioid antagonist naltrexone still needs clear investigation, including comparison of the established oral form with the new ultra-long-acting depot implant formulations (for which no licensed products exist in Europe). Despite the small number of study participants, some tentative conclusions can be reached, relevant to potential future work. The blinding of the active/placebo medications appeared to be good. Self-report was not sufficient to detect instances of heroin use. Self-report plus UDS information provided a fuller picture. Instances of lapsed heroin use were not necessarily followed by full relapse, and future work should consider the lapse-relapse relationship. The prison release setting also warrants special consideration. In future, investigators should consider seeking ethics approval for studies in which clinical procedures to accelerate the treatment process are permitted, even if outside orthodox clinical practice, if they address a clinical need at the time of challenge and clinical risk. In addition, it may be appropriate to seek exemption from the ordinary requirement of a cooling-off period after securing consent because it is often essential to initiate treatment promptly. TRIAL REGISTRATION: Current Controlled Trials ISRCTN95809946. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 3. See the NIHR Journals Library website for further project information.

County-level access to opioid use disorder medications in medicare Part D (2010-2015).

OBJECTIVE: To identify geographic disparities in access to opioid use disorder (OUD) treatment medications and county demographic and economic characteristics associated with access to buprenorphine and oral naltrexone prescribers in Medicare Part D. DATA SOURCES/STUDY SETTING: We utilized data from the Medicare Part D Prescription Drug Event Standard Analytic File (2010-2015). STUDY DESIGN/DATA COLLECTION: We used logistic regression to examine county-level access to OUD medication prescribers. PRINCIPAL FINDINGS: There was a 5.6 percentage point increase in counties with access to an OUD prescriber over the study period. However, in 2015, 60 percent of US counties lacked access to a Medicare Part D buprenorphine prescriber and over 75 percent lacked access to an oral naltrexone prescriber. Increased access to OUD prescribers was largely concentrated in urban counties. Results of logistic regression indicate regional differences and potential racial disparities in access to OUD prescribers. CONCLUSIONS: To improve access to buprenorphine and naltrexone treatment for Medicare Part D enrollees, CMS may consider implementing educational and training initiatives focused on OUD treatment, offering training to obtain a buprenorphine waiver at no cost to providers, and sending targeted information to providers in low OUD treatment capacity areas.

A qualitative assessment of attitudes about and preferences for extended-release naltrexone, a new pharmacotherapy to treat opioid use disorders in Ukraine.

Numerous individual barriers, including negative attitudes toward opioid agonist therapies (OAT), have undermined HIV prevention efforts in Ukraine where the epidemic is concentrated in people who inject drugs (PWID). The recent availability of extended-release naltrexone (XR-NTX), an opioid antagonist, provides new opportunities for treatment and prevention, but little is known about patient preferences. We conducted qualitative analysis using focus groups (FG) of PWID recruited based on OAT experience: currently, previously, and never on OAT in five Ukrainian cities. FG included 199 PWID in 25 focus groups. Focus group transcripts were coded and analyzed using a modified grounded theory approach to identify common themes and domains related to attitudes about and preferences for XR-NTX, relative to other treatments. Interest in XR-NTX was supported if supervised opioid withdrawal and psychological support were assured. Other factors supporting XR-NTX included a focus on younger PWID early in their injection career and motivated for recovery. Perceptions of recovery included not receiving psychoactive medications like methadone or buprenorphine. With more information, XR-NTX could be a viable option for PWID in Ukraine, especially if concerns regarding withdrawal and psychological support are adequately addressed.

Injectable naltrexone, oral naltrexone, and buprenorphine utilization and discontinuation among individuals treated for opioid use disorder in a United States commercially insured population.

We investigated prescribing patterns for four opioid use disorder (OUD) medications: 1) injectable naltrexone, 2) oral naltrexone, 3) sublingual or oralmucosal buprenorphine/naloxone, and 4) sublingual buprenorphine as well as transdermal buprenorphine (which is approved for treating pain, but not OUD) in a nationally representative claims-based database (Truven Health MarketScan®) of commercially insured individuals in the United States. We calculated the prevalence of OUD in the database for each year from 2010 to 2014 and the proportion of diagnosed patient months on OUD medication. We compared characteristics of individuals diagnosed with OUD who did and did not receive these medications with bivariate descriptive statistics. Finally, we fit a Cox proportional hazards model of time to discontinuation of therapy as a function of therapy type, controlling for relevant confounders. From 2010 to 2014, the proportion of commercially insured individuals diagnosed with OUD grew by fourfold (0.12% to 0.48%), but the proportion of diagnosed patient-months on medication decreased from 25% in 2010 (0.05% injectable naltrexone, 0.4% oral naltrexone, 23.1% sublingual or oralmucosal buprenorphine/naloxone, 1.5% sublingual buprenorphine, and 0% transdermal buprenorphine) to 16% in 2014 (0.2% injectable naltrexone, 0.4% oral naltrexone, 13.8% sublingual or oralmucosal buprenorphine/naloxone, 1.4% sublingual buprenorphine, and 0.3% transdermal buprenorphine). Individuals who received medication therapy were more likely to be male, younger, and have an additional substance use disorder compared with those diagnosed with OUD who did not receive medication therapy. Those prescribed injectable naltrexone were more often male, younger, and diagnosed with additional substance use disorders compared with those prescribed other medications for opioid use disorder (MOUDs). At 30 days after initiation, 52% for individuals treated with injectable naltrexone, 70% for individuals treated with oral naltrexone, 31% for individuals treated with sublingual or oralmucosal buprenorphine/naloxone, 58% for individuals treated with sublingual buprenorphine, and 51% for individuals treated with transdermal buprenorphine discontinued treatment. In the Cox proportional hazard model, use of injectable naltrexone, oral naltrexone, sublingual buprenorphine, and transdermal buprenorphine were all associated with significantly greater hazard of discontinuing therapy beginning >30days after MOUD initiation (HR=2.17, 2.54, 1.15, and 2.21, respectively, 95% CIs 2.04-2.30, 2.45-2.64, 1.10-1.19, and 2.11-2.33), compared with the use of sublingual or oralmucosal buprenorphine/naloxone. This analysis demonstrates that the use of evidence-based medication therapies has not kept pace with increases in OUD diagnoses in commercially insured populations in the United States. Among those who have been treated, discontinuation rates >30days after initiation are high. The proportion treated with injectable naltrexone, oral naltrexone, and transdermal buprenorphine grew over time but remains small, and the discontinuation rates are higher among those treated with these medications compared with those treated with sublingual or oralmucosal buprenorphine/naloxone. In the face of the opioid overdose and addiction crisis, new efforts are needed at the provider, health system, and policy levels so that MOUD availability and uptake keep pace with new OUD diagnoses and OUD treatment discontinuation is minimized.

Low-threshold extended-release naltrexone for high utilizers of public services with severe alcohol use disorder: A pilot study.

Extended-release naltrexone (XRNTX) is an effective treatment for alcohol use disorder (AUD). We sought to evaluate the feasibility, acceptability, and preliminary effectiveness and cost-effectiveness of XRNTX delivered as a stand-alone service to persons with severe AUD who are high utilizers of multiple urgent and emergency medical services (HUMS). Of 15 HUMS persons with severe AUD selected based on chart review, 11 agreed to participate. Participants received a mean of 4.5 injections (range 2-7). Modest benefits from XRNTX were observed in terms of patients' Urge-to-Drink Score and the costs of emergency medical services utilized. Though limited by a small sample size, costs including client utilization and study related expenses during the post-enrollment period were less than client utilization costs in the pre-enrollment period. We also observed non-significant improvements in the number of drinking days, but no change in quality of life as measured by the EQ-5D. Eighty-eight percent of participants perceived XRNTX as helping with their drinking. Findings need to be replicated in a larger study, however if replicated, the cost savings could be substantial.

Cost-Effectiveness of Nalmefene Added to Psychosocial Support for the Reduction of Alcohol Consumption in Alcohol-Dependent Patients With High/Very High Drinking Risk Levels: A Microsimulation Model.

OBJECTIVE: A microsimulation model was adapted to evaluate the cost-effectiveness of nalmefene combined with psychosocial support (NMF + PS) versus psychosocial support alone (PS). The economic impact of alcohol reduction using nalmefene treatment was not evaluated. METHOD: The model simulates patient-level alcohol consumption over a 5-year time horizon across different treatment cohorts. Study outcomes included probabilities of alcohol-attributable diseases and injuries as well as deaths from these events. The approach used nalmefene clinical trial data, a time horizon of 1 and 5 years, and a U.K. societal perspective. Extensive deterministic and probabilistic sensitivity analyses were conducted. RESULTS: Compared with the PS strategy, NMF + PS was associated at Year 5 with a gain of 0.047 quality-adjusted life years (QALYs) and an additional £503, leading to an incremental cost-effectiveness ratio (ICER) of £10,613 per QALY gained. When compared with the strategy without treatment, NMF + PS was associated with a gain of 0.228 QALYs and an additional £1,795, leading to an ICER of £1,758 per QALY gained. The NMF + PS strategy dominated both treatment strategies when considering the U.K. societal perspective. Sensitivity analyses confirmed the robustness of the results. CONCLUSIONS: A combination of NMF and PS was better than PS alone, considering a 5-year time horizon and a societal perspective.

Safety assessment of combination therapies in the treatment of obesity: focus on naltrexone/bupropion extended release and phentermine-topiramate extended release.

INTRODUCTION: Few studies on combination therapies for the treatment of obesity had been conducted until recently, when two fixed-dose combinations, bupropion-naltrexone ER fixed-dose combination and phentermine-topiramate ER titrated-dose combinations were evaluated in clinical studies that ultimately led to FDA approval. Areas covered: In this review, we discuss safety concerns about both combinations, the rationale and history of combination therapies for obesity (including phentermine plus fenfluramine), and possible future new combinations. Expert opinion: Combination therapies are a promising new area in obesity treatment, similar to what occurs with diabetes and hypertension. Safety assessment is highly important due to the high number of potential users on a chronic basis.

What's in a number? Recommending practicality in the DATA 2000 patient limits.

According to the Substance Abuse and Mental Health Services Administration, 2.4 million individuals have an opioid use disorder (OUD). Yet, nearly 80 percent of them-more than 1.9 million people-do not receive treatment. Medication-assisted treatment (MAT), specifically with buprenorphine, has proven to be effective in treating patients with OUDs while also reducing costs to the healthcare system, criminal justice system, and workforce. Despite its effectiveness, barriers to MAT continue to exist. Consequently, many individuals must wait months, if not years, to receive treatment. This article analyzes the US Department of Health and Human Services' final rule (Final Rule) on MAT, common barriers to treatment, and the cost-benefit of treatment in light of the current opioid abuse epidemic. The article finds that while the Final Rule was a step in the right direction, it does not go far enough to adequately address the epidemic. Finally, the article proposes practical recommendations for increasing patient access to treatment for OUDs, including increasing the patient limit for highly qualified addiction treatment providers so that they can practice addiction medicine on a full-time basis and exempting buprenorphine products labeled by the US Food and Drug Administration for direct administration from the practitioner's patient limit.

NIDA Clinical Trials Network CTN-0051, Extended-Release Naltrexone vs. Buprenorphine for Opioid Treatment (X:BOT): Study design and rationale.

INTRODUCTION: For opioid-dependent patients in the US and elsewhere, detoxification and counseling-only aftercare are treatment mainstays. Long-term abstinence is rarely achieved; many patients relapse and overdose after detoxification. Methadone, buprenorphine-naloxone (BUP-NX) and extended-release naltrexone (XR-NTX) can prevent opioid relapse but are underutilized. This study is intended to develop an evidence-base to help patients and providers make informed choices and to foster wider adoption of relapse-prevention pharmacotherapies. METHODS: The National Institute on Drug Abuse's Clinical Trials Network (CTN) study CTN-0051, X:BOT, is a comparative effectiveness study of treatment for 24weeks with XR-NTX, an opioid antagonist, versus BUP-NX, a high affinity partial opioid agonist, for opioid dependent patients initiating treatment at 8 short-term residential (detoxification) units and continuing care as outpatients. Up to 600 participants are randomized (1:1) to XR-NTX or BUP-NX. RESULTS: The primary outcome is time to opioid relapse (i.e., loss of persistent abstinence) across the 24-week treatment phase. Differences between arms in the distribution of time-to-relapse will be compared (construction of the asymptotic 95% CI for the hazard ratio of the difference between arms). Secondary outcomes include proportions retained in treatment, rates of opioid abstinence, adverse events, cigarette, alcohol, and other drug use, and HIV risk behaviors; opioid cravings, quality of life, cognitive function, genetic moderators, and cost effectiveness. CONCLUSIONS: XR-NTX and BUP-NX differ considerably in their characteristics and clinical management; no studies to date have compared XR-NTX with buprenorphine maintenance. Study design choices and compromises inherent to a comparative effectiveness trial of distinct treatment regimens are reviewed. CLINICAL TRIAL REGISTRATION: NCT02032433.

A Comparison of Markov and Discrete-Time Microsimulation Approaches: Simulating the Avoidance of Alcohol-Attributable Harmful Events from Reduction of Alcohol Consumption Through Treatment of Alcohol Dependence.

BACKGROUND AND OBJECTIVE: When modelling the pathophysiology of a disease, it is important to select a modelling approach that can adequately replicate its course. The objective of this paper was to compare the outcomes obtained by the Markov and discrete-time microsimulation modelling approaches using nalmefene clinical trial data. METHODS: Markov and microsimulation modelling approaches assessing alcohol dependence treatment with psychosocial support with or without nalmefene were compared in terms of the modelled evolution of patients' alcohol consumption and the resulting occurrence of alcohol-attributable harmful events over 1 year. RESULTS: Comparison of the proportion of the modelled population at different levels of alcohol consumption over time revealed systematic differences arising from the different modelling techniques: a lower number of patients reaching abstinence, a higher number of patients at higher drinking levels, and, overall, a smoother evolution of alcohol consumption in the microsimulation. Reasons are discussed in the paper. While the models produced similar occurrences of alcohol-attributable harmful events as a whole, distinct results for the individual events were observed, explained by the specific pathophysiology of occurrence of these events and how their implementation was adapted to fit the limitations of the compared modelling approaches; however, these differences were only statistically significant for one of the eight events. CONCLUSIONS: For a general public health or health economic assessment of alcohol use disorders, it is possible to achieve similar results with the compared approaches. To assess a patients' disease course, taking into consideration alcohol-attributable harmful events, the microsimulation approach may provide more precise results. However, further external validation of the models is needed and this additional precision may be outweighed by the greater computational burden of a microsimulation approach.

Extended-Release Naltrexone: A Qualitative Analysis of Barriers to Routine Use.

The Medication Research Partnership (a national health plan and nine addiction treatment centers contracted with the health plan) sought to facilitate the adoption of pharmacotherapy for alcohol and opioid use disorders. Qualitative analysis of interviews with treatment center change leaders, individuals working for the manufacturer and its technical assistance contractor, and health plan managers extracted details on the processes used to order, store, bill for, and administer extended-release naltrexone. Qualitative themes were categorized using domains from the Consolidated Framework for Implementation Research (intervention characteristics, outer setting, inner setting, and provider characteristics). Characteristics of XR-NTX that inhibited use included the complexity of ordering and using the medication; cost was also a barrier. Outer setting barriers reflected patient needs and external health plan policies on formulary coverage, benefit management, and reimbursement. Program structures, the lack of physician linkages, a culture resistant to the use of medication, and unease with change were inner setting elements that limited use of XR-NTX. Patient stereotypes and a lack of knowledge about XR-NTX affected practitioner willingness to treat patients and prescribe XR-NTX. The Consolidated Framework for Implementation Research provided a useful lens to understand and interpret the processes affecting access to XR-NTX.

Cortisol Stress Response in Men and Women Modulated Differentially by the Mu-Opioid Receptor Gene Polymorphism OPRM1 A118G.

Differences in stress reactivity may affect long-term health outcomes, but there is little information on how these differences arise. The stress axis is regulated by, in part, the endogenous opioid, beta-endorphin, acting on mu-opioid receptors. Persons carrying one or two copies of the G allele of the mu-opioid receptor gene (OPRM1 A118G) may have higher receptor binding for beta-endorphin compared with AA homozygotes that may contribute to individual differences in cortisol reactivity to stress, leading to a relative blunting of cortisol stress reactivity in G allele genotypes. We measured cortisol in 251 young adults (69 GA/GG vs 182 AA genotypes) exposed to mental arithmetic plus public speaking stress relative to a resting control day. Women had smaller cortisol responses than men (F=10.2, p=0.002), and women with GA or GG genotypes (N=39) had an absence of cortisol response relative to AA carriers (N=110) (F=18.4, p<0.0001). Male genotypes had no such difference in response (F=0.29). Cortisol response following mu-opioid receptor blockade using naltrexone in 119 of these subjects unmasked a greater tonic opioid inhibition of cortisol secretion in women (N=64), consistent with their blunted stress reactivity. Compared with men, women may have cortisol stress responses that are more heavily regulated by endogenous opioid mechanisms, and the OPRM1 GA/GG genotypes may affect females differentially relative to males. Diminished cortisol responses to stress may have consequences for health behaviors in women with GA/GG genotypes.