A week-long outpatient induction onto XR-naltrexone in patients with opioid use disorder

A historical perspective on clonidine as an alpha-2A receptor agonist in the treatment of addictive behaviors: Focus on opioid dependence

Clonidine operates through agonism at the alpha-2A receptor, a specific subtype of the alpha-2-adrenergic receptor located predominantly in the prefrontal cortex. By inhibiting the release of norepinephrine, which is responsible for withdrawal symptoms, clonidine effectively addresses withdrawal-related conditions such as anxiety, hypertension, and tachycardia. The groundbreaking work by Gold et al. demonstrated clonidine's ability to counteract the effects of locus coeruleus stimulation, reshaping the understanding of opioid withdrawal within the field. In the 1980s, the efficacy of clonidine in facilitating the transition to long-acting injectable naltrexone was confirmed for individuals motivated to overcome opioid use disorders (OUDs), including physicians and executives. Despite challenges with compliance, naltrexone offers sustained blockade of opioid receptors, reducing the risk of overdose, intoxication, and relapse in motivated patients in recovery. The development of clonidine and naltrexone as treatment modalities for OUDs, and potentially other addictions, including behavioral ones, underscores the potential for translating neurobiological advancements from preclinical models (bench) to clinical practice (bedside), ushering in innovative approaches to addiction treatment.

Informing evidence-based medicine for opioid use disorder using pharmacoeconomic studies

INTRODUCTION

The health and economic consequences of inadequately treated opioid use disorder (OUD) are substantial. Healthcare systems in the United States (US) and other countries are facing a growing healthcare crisis due to opioids. Although effective medications for OUD exist, relying solely on clinical information is insufficient for addressing the opioid crisis.

AREAS COVERED

In this review, the role of pharmacoeconomic studies in informing evidence-based medication treatment for OUD is discussed, with a particular emphasis on the US healthcare system, where the economic burden is significantly higher than the global average. The scope/objective of pharmacoeconomics as a distinct scientific research program is briefly defined, followed by a discussion of existing evidence informed by data from systematic reviews, in addition to a convenience sample of recently published pharmacoeconomic studies and protocols. The review also explores the need for methodological advancements in the field.

EXPERT OPINION

Despite the potential of pharmacoeconomic research in shaping evidence-based medicine for OUD, significant challenges limiting its real-world application remain. How to address these challenges are explored, including how to combine cost-effectiveness and budget impact analyses to address the needs of the healthcare system as a whole and specific stakeholders interested in adopting new OUD treatment strategies.

Open label trial of lofexidine-assisted non-opioid induction onto naltrexone extended-release injection for opioid use disorder

Background: Opioid use disorder (OUD) continues to be major public health problem in the US and innovative medication strategies are needed. The extended-release injectable formulation of naltrexone (ER-NTX), an opioid receptor antagonist, is an effective treatment for OUD, but the need for an opioid-free period during the induction phase of treatment is a barrier to treatment success, particularly in the outpatient setting. Lofexidine, an alpha-2-adrenergic agonist, is an effective treatment for opioid withdrawal.Objectives: To evaluate the feasibility, safety, and tolerability of lofexidine for facilitating induction onto ER-NTX in the management of OUD.Methods: In an open-label, uncontrolled, 10-week outpatient clinical trial, 20 adults (four women) with OUD were treated with a fixed-flexible dosing strategy (maximum 0.54 mg 4×/daily) of lofexidine for up to 10 days to manage opioid withdrawal prior to receiving ER-NTX. The COVID-19 pandemic resulted in a modification of the study methods after enrolling 10 participants who attended all visits in person. The second group of 10 participants attended most induction period visits remotely.Results: Overall, 10 of the 20 participants (50%) achieved the primary outcome by receiving the first ER-NTX injection. Rates of induction success did not differ by the presence of fentanyl or remote visit attendance, although the small sample size provided limited statistical power. Six out of 20 participants (30%) initiated on lofexidine required dose adjustments. There were no study-related serious adverse events.Conclusions: This study provides preliminary evidence supporting the feasibility of inducting individuals with OUD onto ER-NTX using lofexidine.

Patient characteristics associated with initiation of XR-naltrexone for opioid use disorder in clinical trials

BACKGROUND

Extended-release injectable naltrexone (XR-naltrexone) is effective for treatment of patients with opioid use disorder (OUD), but initiation remains a barrier due to the challenge of tolerating opioid withdrawal prior to administration. Understanding factors associated with successful initiation of XR-naltrexone could facilitate its implementation through patient-treatment matching.

METHODS

We combined data from five consecutive studies that sought to initiate patients with active opioid use onto XR-naltrexone using a rapid procedure consisting of minimal buprenorphine, non-opioid medications for treating opioid withdrawal, and ascending low doses of oral naltrexone. Associations between patient characteristics and initiating naltrexone were estimated with logistic regression models. To evaluate whether associations differed between inpatient and outpatient settings, patient characteristic-by-setting interactions were also estimated.

RESULTS

409 patients were included in the analyses and 228 (56%) received the first injection. A significantly greater percent of inpatients (62%) vs outpatients (48%) initiated XR-naltrexone. Initiation success was significantly more likely on an inpatient basis for heroin (60.9% inpatient vs 36.2% outpatient), intravenous (56.3% inpatient vs 22.5% outpatient), and speedball users (68.1% inpatient vs 32.3% outpatient). Prescription opioid users showed similar, higher initiation rates across settings (68.9% inpatient; 73.7% outpatient).

CONCLUSIONS

An inpatient setting may be the preferred strategy for rapid initiation of XR-naltrexone for opioid users with greater severity, including heroin or speedball injection users or those who use opioids intravenously. Initiation on an outpatient basis may be more likely to succeed for prescription opioid users.

Initiating Long-acting Injectable Naltrexone: Procedure for a Second Attempt After a First Attempt Fails

BACKGROUND AND OBJECTIVE

Many patients are unable to initiate long-acting injectable naltrexone (XR-NTX) on a first attempt, due to the prerequisite abstinence and withdrawal from opioids.

METHODS

Thirty patients who were unable to initiate XR-NTX were recruited to receive buprenorphine for 1 week, followed by a 3-week buprenorphine taper, and an ascending titration of oral naltrexone before XR-NTX injection.

RESULTS

Eight (27%) initiated XR-NTX, 7 (23%) transitioned to buprenorphine maintenance treatment and 15 (50%) were lost to follow up.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

A second attempt at XR- NTX initiation using buprenorphine stabilization and cross taper may be a reasonable approach for some patients.

Associations between fentanyl use and initiation, persistence, and retention on medications for opioid use disorder among people living with uncontrolled HIV disease

BACKGROUND

Associations between fentanyl use and initiation and retention on medications for opioid use disorder (MOUD) are poorly understood.

METHODS

Data were from a multisite clinical trial comparing extended-release naltrexone (XR-NTX) with treatment as usual (TAU; buprenorphine or methadone) to achieve HIV viral suppression among people with OUD and uncontrolled HIV disease. The exposure of interest was fentanyl use, as measured by urine drug screening. Outcomes were time to MOUD initiation, defined as date of first injection of XR-NTX, buprenorphine prescription, or methadone administration; MOUD persistence, the total number of injections, prescriptions, or administrations received over 24 weeks; and MOUD retention, having an injection, prescription, or administration during weeks 20-24.

RESULTS

Participants (N = 111) averaged 47 years old and 62% were male. Just over half (57%) were Black and 13% were Hispanic. Sixty-four percent of participants tested positive for fentanyl at baseline. Participants with baseline fentanyl positivity were 11 times less likely to initiate XR-NTX than those negative for fentanyl (aHR = 0.09, 95% CI 0.03-0.24, p < .001), but there was no evidence that fentanyl use impacted the likelihood of TAU initiation (aHR = 1.50, 0.67-3.36, p = .323). Baseline fentanyl use was not associated with persistence or retention on any MOUD.

CONCLUSIONS

Fentanyl use was a substantial barrier to XR-NTX initiation for the treatment of OUD in persons with uncontrolled HIV infection. There was no evidence that fentanyl use impacted partial/full agonist initiation and, once initiated, retention on any MOUD.

Treatment of opioid use disorder in primary care

Opioid use disorder (OUD) is a common, treatable chronic disease that can be effectively managed in primary care settings. Untreated OUD is associated with considerable morbidity and mortality-notably, overdose, infectious complications of injecting drug use, and profoundly diminished quality of life. Withdrawal management and medication tapers are ineffective and are associated with increased rates of relapse and death. Pharmacotherapy is the evidence based mainstay of OUD treatment, and many studies support its integration into primary care settings. Evidence is strongest for the opioid agonists buprenorphine and methadone, which randomized controlled trials have shown to decrease illicit opioid use and mortality. Discontinuation of opioid agonist therapy is associated with increased rates of relapse and mortality. Less evidence is available for the opioid antagonist extended release naltrexone, with a meta-analysis of randomized controlled trials showing decreased illicit opioid use but no effect on mortality. Treating OUD in primary care settings is cost effective, improves outcomes for both OUD and other medical comorbidities, and is highly acceptable to patients. Evidence on whether behavioral interventions improve outcomes for patients receiving pharmacotherapy is mixed, with guidelines promoting voluntary engagement in psychosocial supports, including counseling. Further work is needed to promote the integration of OUD treatment into primary care and to overcome regulatory barriers to integrating methadone into primary care treatment in the US.

Lorcaserin treatment for extended-release naltrexone induction and retention for opioid use disorder individuals: A pilot, placebo-controlled randomized trial

BACKGROUND

Opioid Use Disorder (OUD) is a significant public health problem associated with severe morbidity and mortality. While effective pharmacotherapies are available, limitations exist with each. Induction onto extended-release naltrexone (XR-NTX) is more difficult than initiation of buprenorphine or methadone, even in inpatient settings, as it is recommended that patients remain abstinent for at least 7 days prior to initiating XR-NTX. The purpose of this trial was to determine if lorcaserin, a 5HT2c agonist, improves outpatient XR-NTX induction rates.

METHODS

An 8-week trial beginning with a brief detoxification period and induction onto XR-NTX. Sixty participants with OUD were enrolled in the trial, with 49 participants at the initiation of detoxification randomized to lorcaserin or placebo for 39 days. Additionally, ancillary medications were provided. The primary outcome was the proportion of participants inducted onto the first XR-NTX injection. Secondary outcomes were withdrawal severity (measured by COWS and SOWS) prior to the first injection and the proportion of participants receiving the second XR-NTX injection.

RESULTS

The proportion of participants inducted onto the first (lorcaserin: 36 %; placebo: 44 %; p = .67) and the second XR-NTX injection (lorcaserin: 27 %; placebo: 31 %; p = .77) was not significantly different between treatment arms. Prior to the first injection, withdrawal scores did not significantly differ between treatment arms over time (treatment*time interaction COWS: p = .11; SOWS: p = .39).

CONCLUSIONS

Lorcaserin failed to improve outpatient XR-NTX induction rates. Although this study is small, the findings do not support the use of lorcaserin in promoting induction onto XR-NTX or in mitigating withdrawal symptoms.

Young Adults Have Worse Outcomes Than Older Adults: Secondary Analysis of a Medication Trial for Opioid Use Disorder

PURPOSE

Young adults are disproportionately affected by the current opioid crisis. Although medications for opioid use disorder are broadly effective, with reductions in morbidity and mortality, the particular effectiveness of medications for opioid use disorder among young adults is less well understood.

METHODS

This secondary analysis compared young adults (aged 18-25 years) with older adults (aged ≥26 years) in a large comparative effectiveness trial ("XBOT") that randomized subjects to extended-release naltrexone or sublingual buprenorphine-naloxone for 6 months. Opioid relapse was defined by opioid use over four consecutive weeks or seven consecutive days, using urine testing and self-report.

RESULTS

Among subjects in the intention-to-treat sample (n = 570, all randomized participants), a main effect of age group was found, with higher relapse rates among young adults (70.3%) compared with older adults (58.2%), with an odds ratio of 1.72 (95% confidence interval = 1.08-2.70), p = .02. In the per-protocol sample (n = 474, only participants who started medication), relapse rates were higher among young adults (66.3%) compared with older adults (50.8%), with an odds ratio of 1.91 (95% confidence interval = 1.19-3.06). Among the intention-to-treat sample, survival analysis revealed a significant time-by-age group interaction (p = .01) with more relapse over time in young adults. No significant interactions between age and medication group were detected.

CONCLUSIONS

Young adults have increased rates of relapse compared with older adults, perhaps because of vulnerabilities that increase their risk for treatment dropout and medication nonadherence, regardless of medication assignment. These results suggest that specialized, developmentally informed interventions may be needed to improve retention and successful treatment of opioid use disorder among young adults.