Patients' perspectives on initiating treatment with extended-release naltrexone (XR-NTX)

Reward Sensitivity in Patients Receiving Opioid Agonist and Antagonist Treatment for Opioid Use Disorder: An Observational Study

BACKGROUND

Disrupted reward processing is a core component in neurobiological theories of addictions, including opioid use disorder (OUD). While acute opioid agonist and antagonist administration can modulate reward behavior and experiences, it remains unclear how typical long-term OUD treatment with these medications impact patients' sensitivity to substance-free rewards. We therefore conducted a cross-sectional study of reward sensitivity in opioid agonist- and antagonist-treated OUD patients, and healthy volunteers.

METHODS

Ninety-six OUD patients on extended-release naltrexone (n=45) or opioid agonists (n=51) and 50 healthy volunteers completed a probabilistic reward task (PRT) and self-report measures of anhedonia, depression, preoccupation with immediate consequences, substance craving and life satisfaction in a single session. We used signal detection analysis and drift diffusion modeling to derive behavioral reward bias measures from PRT performance. Group differences were modeled with beta and linear regression.

RESULTS

Patients reported significantly greater anhedonia (Cohen's ds≥0.64), depression (ds≥0.53) and preoccupation with immediate consequences (ds≥0.54) than heathy volunteers, but differences between naltrexone- and opioid agonist-treated patients were non-significant (ds≤0.26). Group differences in behavioral reward bias were small and non-significant (ps=1, BF01s≥84.13). Anhedonia was significantly associated with lower life satisfaction (OR [95% CI]=1.10 [1.04, 1.17]). There were no other significant associations between reward sensitivity measures and life satisfaction or craving (ps≥0.31, BF01s≥2.58).

CONCLUSION

These data support an association between OUD and reduced well-being irrespective of opioid agonist or antagonist treatment, highlighting patients' need for psychosocial support and/or adjunct interventions. Major detrimental effects of naltrexone treatment on well-being seem unlikely from these and previous results.

Pain intensity in patients using extended-release naltrexone or opioid agonists and its effect on extended-release naltrexone treatment outcomes

BACKGROUND AND OBJECTIVES

Extended-release naltrexone (XR-NTX) is an opioid antagonist effective for treating opioid use disorder (OUD). However, concerns about inadequate pain management may limit its use. This study will examine changes in pain intensity in OUD patients choosing XR-NTX compared to opioid agonist treatment (OAT), identify subgroups with distinct pain intensity trajectories, and assess the effect of pain intensity on XR-NTX treatment outcomes (retention, relapse, opioid use, and cravings).

METHODS

This 24-week study included OUD patients aged 18-65 years opting for XR-NTX (n = 160). Patients receiving OAT (n = 151) served as controls. Pain intensity was measured every 4 weeks for XR-NTX and at baseline and Week 24 for OAT using the numerical pain rating scale-11 (NPRS-11). Data were analyzed with linear mixed models and group-based trajectory modeling.

RESULTS

Between baseline and Week 24, XR-NTX participants with low to moderate pain showed a significant reduction in pain intensity, while those with high pain did not. In the OAT group, no significant reduction in pain intensity was observed (from baseline to Week 24). Pain intensity was not associated with XR-NTX treatment outcomes.

DISCUSSION AND CONCLUSIONS

Contrary to perception, XR-NTX does not worsen pain intensity, nor did pain intensity affect XR-NTX treatment outcomes.

SCIENTIFIC SIGNIFICANCE

This study is the first to explore the association between changes in pain intensity and XR-NTX treatment outcomes in OUD patients over a 24-week period. The findings challenge the perception that XR-NTX is less suitable for treating OUD patients with pain.

Perceptions of People Who Inject Drugs About Long-acting Medications for Opioid Use Disorder, Preexposure Prophylaxis, and Antiretroviral Therapy

Background

Long-acting injectable (LAI) forms of preexposure prophylaxis and antiretroviral therapy and extended-release medications for opioid use disorder (OUD) may reduce HIV and OUD treatment attrition, but community interest among people who inject drugs remains underexplored.

Methods

From September to December 2023, we conducted a cross-sectional survey of adults with OUD and a history of injection drug use who were attending a New Jersey syringe exchange program to assess their experiences with HIV and OUD care and their knowledge, attitudes, and preferences about LAI.

Results

Of 193 participants, 15 were persons with HIV (PWH), 72 were high risk for HIV (HRH), and 91 were low risk for HIV (LRH). Many participants had previously taken medications for OUD (60%), but knowledge of extended-release medications for OUD was low (40% PWH, 45.8% HRH, 41.6% LRH, P = .85). Participant interest in extended-release naltrexone (33.3% PWH, 27.8% HRH, 26.7% LRH, P = .91) and extended-release buprenorphine (33.3% PWH, 18.3% HRH, 20.9% LRH, P = .45) was also low. Preexposure prophylaxis knowledge was high (59.1% HRH, 63.9% LRH, P = .54), but prior usage (11.1% HRH, 6.7% LRH, P = .32) and interest (18.1% HRH, 21.1% LRH P = .63) in LAI preexposure prophylaxis were low. PWH had high awareness (66.7%) and interest (66.7%) in receiving LAI antiretroviral therapy. Interest in integrated care was greater for PWH (69.2%) than for those at HRH (29.8%) or LRH (33.9%; P = .03), and preferred treatment locations varied among the groups.

Conclusions

Targeted education and outreach are particularly needed for extended-release medications for OUD and LAI preexposure prophylaxis. A differentiated care model may better address the needs of people who inject drugs with OUD, whether at risk for or with HIV. Addressing barriers to LAI treatment remains essential.

Pain Intensity in Patients with Opioid Use Disorder on Extended-Release Naltrexone or Opioid Agonists; The Role of COMT rs4680 and OPRM1 rs1799971: An Exploratory Study

Purpose

To examine whether reported pain intensity over time is related to the single nucleotide polymorphisms of the catechol-O-methyltransferase (COMT rs4680) and mu-opioid receptor (OPRM1 rs1799971) in patients with opioid use disorder (OUD) choosing treatment with extended-release naltrexone (XR-NTX) or opioid agonist treatment (OAT).

Patients and Methods

This exploratory study was part of a 24-week, open-label clinical prospective trial of patients with OUD who chose intramuscular XR-NTX, and patients receiving OAT. Men and women aged 18 to 65 years with OUD per the Diagnostic and Statistical Manual of Mental Disorders, fifth edition were included. Pain intensity was measured at baseline and at 24-week follow-up using the Numerical Pain Rating Scale-11 and genotyping was performed by TaqMan technology. Data were analyzed with ordinal logistic regression.

Results

Of 317 participants included at baseline, 210 samples were obtained and analyzed. In the OAT group, there was a negative significant association between pain intensity and having the Val/Val allele of COMT rs4680 (wild-type = most common type) and the rare allele G of OPRM1 rs1799971 at 24-week follow-up. No such effects were seen in the XR-NTX group.

Conclusion

The wild-type allele Val/Val of COMT rs4680 and the rare allele G of OPRM1 rs1799971 may have a possible protective effect regarding pain intensity in patients with OUD receiving OAT. Given relatively low sample size, particularly low number of female participants in the XR-NTX group and other possible confounders, our findings should be interpreted with caution.

Perspectives of substance use disorder counselors on the benefits and drawbacks of medications for opioid use disorder

BACKGROUND

Medications for opioid use disorder (MOUD) are among the best tools available to combat the opioid epidemic. Yet, use of MOUD among people with opioid use disorder (OUD) remains low. Interventions to increase MOUD access in the United States have largely focused on improving organizational capacity and addressing funding barriers, yet stigma toward MOUD may inhibit uptake even where MOUD is readily available. Non-prescribing substance use disorder (SUD) treatment professionals (e.g. counselors) likely have considerable influence on a client's choice to initiate and adhere to MOUD, but beliefs that counselors convey about MOUD in interaction with clients are understudied. The current study explores what advantages and disadvantages that counselors communicate about buprenorphine, methadone, and naltrexone.

METHODS

From June to December 2021, we surveyed counselors from publicly-funded SUD treatment agencies under a municipality-wide mandate to offer MOUD to all clients with OUD. Counselors were asked to describe, in a free-response format, the most important advantages and disadvantages to communicate to their clients about taking buprenorphine, methadone, and naltrexone. Counselor responses were coded for one or more advantage and disadvantage.

RESULTS

A total of 271 SUD counselors from 29 agencies in the Philadelphia Metropolitan Area completed the survey, generating 1,995 advantages and disadvantages across three types of MOUD. The most frequently reported advantage across all three types of MOUD was their ability to reduce cravings and illicit drug use. The most frequently reported disadvantage related to the potential for some types of MOUD to develop long-term medication dependence.

CONCLUSIONS

As the availability and variety of MOUD treatment options continue to expand, it is important that SUD counselors are equipped with evidence-based recommendations for OUD care. We identified misalignments with the MOUD-prescribing evidence base and stigmatizing language toward MOUD within counselors' responses, highlighting the potential to refine training materials for MOUD and mitigate stigmatizing beliefs.

Estimating the impact of stimulant use on initiation of buprenorphine and extended-release naltrexone in two clinical trials and real-world populations

BACKGROUND

Co-use of stimulants and opioids is rapidly increasing. Randomized clinical trials (RCTs) have established the efficacy of medications for opioid use disorder (MOUD), but stimulant use may decrease the likelihood of initiating MOUD treatment. Furthermore, trial participants may not represent "real-world" populations who would benefit from treatment.

METHODS

We conducted a two-stage analysis. First, associations between stimulant use (time-varying urine drug screens for cocaine, methamphetamine, or amphetamines) and initiation of buprenorphine or extended-release naltrexone (XR-NTX) were estimated across two RCTs (CTN-0051 X:BOT and CTN-0067 CHOICES) using adjusted Cox regression models. Second, results were generalized to three target populations who would benefit from MOUD: Housed adults identifying the need for OUD treatment, as characterized by the National Survey on Drug Use and Health (NSDUH); adults entering OUD treatment, as characterized by Treatment Episodes Dataset (TEDS); and adults living in rural regions of the U.S. with high rates of injection drug use, as characterized by the Rural Opioids Initiative (ROI). Generalizability analyses adjusted for differences in demographic characteristics, substance use, housing status, and depression between RCT and target populations using inverse probability of selection weighting.

RESULTS

Analyses included 673 clinical trial participants, 139 NSDUH respondents (weighted to represent 661,650 people), 71,751 TEDS treatment episodes, and 1,933 ROI participants. The majority were aged 30-49 years, male, and non-Hispanic White. In RCTs, stimulant use reduced the likelihood of MOUD initiation by 32% (adjusted HR [aHR] = 0.68, 95% CI 0.49-0.94, p = 0.019). Stimulant use associations were slightly attenuated and non-significant among housed adults needing treatment (25% reduction, aHR = 0.75, 0.48-1.18, p = 0.215) and adults entering OUD treatment (28% reduction, aHR = 0.72, 0.51-1.01, p = 0.061). The association was more pronounced, but still non-significant among rural people injecting drugs (39% reduction, aHR = 0.61, 0.35-1.06, p = 0.081). Stimulant use had a larger negative impact on XR-NTX initiation compared to buprenorphine, especially in the rural population (76% reduction, aHR = 0.24, 0.08-0.69, p = 0.008).

CONCLUSIONS

Stimulant use is a barrier to buprenorphine or XR-NTX initiation in clinical trials and real-world populations that would benefit from OUD treatment. Interventions to address stimulant use among patients with OUD are urgently needed, especially among rural people injecting drugs, who already suffer from limited access to MOUD.

Impact of Impulsivity, Hyperactivity, and Inattention on Discontinuation Rate among Opioid-Dependent Patients Treated with Extended-Release Naltrexone

Previous studies have indicated elevated levels of impulsivity, hyperactivity, and inattention (IHI) among opioid-dependent patients seeking outpatient treatment with extended-release naltrexone (XR-NTX). This led us to hypothesize that IHI may be associated with a higher discontinuation rate for XR-NTX treatment. In a group of 162 patients with opioid dependence, discontinuation prior to the full 24 weeks of the study period (six injections and attending the study visit at 24 weeks) occurred in 49% of the patients, primarily in the early stage of treatment. IHI above the clinical cut-off on the adult ADHD self-report scale (ASRS) was not associated with a risk of premature discontinuation. This finding was not altered when controlling for socio-demographics, substance, use and mental health severity. Conclusively, high levels of IHI per se is not contradictive for XR-NTX treatment in regard to concern for premature discontinuation.

Patients' experiences of continued treatment with extended-release naltrexone: a Norwegian qualitative study

BACKGROUND

The opioid antagonist extended-release naltrexone (XR-NTX) in the treatment of opioid use disorder (OUD) is effective in terms of safety, abstinence from opioid use and retention in treatment. However, it is unclear how patients experience and adjust to losing the possibility of achieving an opioid effect. This qualitative study is the first to explore how people with opioid dependence experience XR-NTX treatment, focusing on the process of treatment over time.

METHODS

Using a purposive sampling strategy, semi-structured interviews were undertaken with 19 persons with opioid use disorder (15 men, four women, 22-55 years of age) participating in a clinical trial of XR-NTX in Norway. The interviewees had received at least three XR-NTX injections. Qualitative content analysis with an inductive approach was used.

FINDINGS

Participants described that XR-NTX treatment had many advantages. However they still faced multiple challenges, some of which they were not prepared for. Having to find a new foothold and adapt to no longer gaining an effect from opioids due to the antagonist medication was challenging. This was especially true for those struggling emotionally and transitioning into the harmful use of non-opioid substances. Additional support was considered crucial. Even so, the treatment led to an opportunity to participate in society and reclaim identity. Participants had strong goals for the future and described that XR-NTX enabled a more meaningful life. Expectations of a better life could however turn into broken hopes. Although participants were largely optimistic about the future, thinking about the end of treatment could cause apprehension.

CONCLUSIONS

XR-NTX treatment offers freedom from opioids and can facilitate the recovery process for people with OUD. However, our findings also highlight several challenges associated with XR-NTX treatment, emphasizing the importance of monitoring emotional difficulties and increase of non-opioid substances during treatment. As opioid abstinence in itself does not necessarily equal recovery, our findings underscore the importance of seeing XR-NTX as part of a comprehensive, individualized treatment approach.

TRIAL REGISTRATION

Clinicaltrials.gov # NCT03647774, first Registered: Aug 28, 2018.

The Predictive Value of Degree of Preference for Extended-Release Naltrexone for Treatment Adherence, Opioid Use, and Relapse

BACKGROUND

Extended-release naltrexone (XR-NTX) is effective for illicit opioid abstinence as an opioid maintenance treatment. To improve treatment outcomes, patient's preference for the modality of treatment is an important factor.

OBJECTIVES

We aimed to test the relationship between baseline preference for XR-NTX and adherence to treatment, use of illicit opioids, and risk of relapse.

METHODS

In an open-label, Norwegian clinical trial participants with opioid use disorder were randomized to either monthly injections with XR-NTX or daily sublingual buprenorphine-naloxone (BP-NLX) for 12 weeks. Subsequently, participants could continue with their preferred medication in a 36-week follow-up and in a prolonged period of 104 weeks.

RESULTS

Of 153 participants who completed detoxification, 72% were men, with a mean age of 36 years. Preference levels were similar across the randomized groups, with no significant associations between preference and adherence to treatment, opioid use, or relapse. The BP-NLX group had a significantly higher risk of first relapse to opioids than the XR-NTX group for all levels of preference (p < 0.001) and a significantly higher number of days of illicit opioid use. In the follow-up period, the adherence rate was twice as high among participants with the highest preference compared to participants with the lowest preference, both among those who switched to XR-NTX and those who continued (hazard ratio 2.2; 1.2-4.0, p = 0.013). Opioid use was significantly higher among participants who switched to XR-NTX with the lowest preference than the medium (p = 0.003) or the highest (p = 0.001) preference. The risk of relapse to opioids, however, was significantly higher among XR-NTX continuing participants with the lowest (p = 0.002) or the medium (p = 0.043) preference than those with the highest preference.

CONCLUSIONS

Individuals who matched with their preferred treatment used less illicit opioids than those who did not during short-term treatment. However, baseline preference for XR-NTX treatment primarily influenced longer term opioid use and treatment adherence.

'Not at all what I had expected': Discontinuing treatment with extended-release naltrexone (XR-NTX): A qualitative study

BACKGROUND

Extended-release naltrexone (XR-NTX), an opioid antagonist, has demonstrated equal treatment outcomes, in terms of safety, opioid use, and retention, to the recommended OMT medication buprenorphine. However, premature discontinuation of XR-NTX treatment is still common and poorly understood. Research on patient experiences of XR-NTX treatment is limited. We sought to explore participants' experiences with discontinuation of treatment with XR-NTX, particularly motivation for XR-NTX, experiences of initiation and treatment, and rationale for leaving treatment.

METHODS

We conducted qualitative, semi-structured interviews with participants from a clinical trial of XR-NTX. The study participants (N = 13) included seven women and six men with opioid dependence, who had received a minimum of one and maximum of four injections of XR-NTX. The study team analyzed transcribed interviews, employing thematic analysis with a critical realist approach.

FINDINGS

The research team identified three themes, and we present them as a chronological narrative: theme 1: Entering treatment - I thought I knew what I was going into; theme 2: Life with XR-NTX - I had something in me that I didn't want; and theme 3: Leaving treatment - I want to go somewhere in life. Patients' unfulfilled expectations of how XR-NTX would lead to a better life were central to decisions about discontinuation, including unexpected physical, emotional, or mental reactions as well as a lack of expected effects, notably some described an opioid effect from buprenorphine. A few participants ended treatment because they had reached their treatment goal, but most expressed disappointment about not achieving this goal. Some also expressed renewed acceptance of OMT. The participants' motivation for abstinence from illegal substances generally remained.

CONCLUSION

Our findings emphasize that a dynamic understanding of discontinuation of treatment is necessary to achieve a long-term approach to recovery: the field should understand discontinuation as a feature of typical treatment trajectories, and discontinuation can be followed by re-initiation of treatment.