Optimal dose of buprenorphine in opioid use disorder treatment: a review of pharmacodynamic and efficacy data

Reconsidering the usefulness of long-term high-dose buprenorphine

Buprenorphine has been successfully used for decades in the treatment of opioid use disorder, yet there are complexities to its use that warrant attention to maximize its utility. While the package insert of the combination product buprenorphine\naloxone continues to recommend a maximum dose of 16 mg daily for maintenance, the emergence of fentanyl and synthetic analogs in the current drug supply may be limiting the effectiveness of this standard dose. Many practitioners have embraced and appropriately implemented novel practices to mitigate the sequelae of our current crisis. It has become common clinical practice to stabilize patients with 24 - 32 mg of buprenorphine daily at treatment initiation. Many of these patients, however, are maintained on these high doses (>16 mg/d) indefinitely, even after prolonged stability. Although this may be a necessary strategy in the short term, there is little evidence to support its safety and efficacy, and these high doses may be exposing patients to more complications and side effects than standard doses. Commonly known side effects of buprenorphine that are likely dose-related include hyperhidrosis, sedation, decreased libido, constipation, and hypogonadism. There are also complications related to the active metabolite of buprenorphine (norbuprenorphine) which is a full agonist at the mu opioid receptor and does not have a ceiling on respiratory suppression. Such side effects can lead to medical morbidity as well as decreased medication adherence, and we, therefore, recommend that after a period of stabilization, practitioners consider a trial of decreasing the dose of buprenorphine toward standard dose recommendations. Some patients' path of recovery may never reach this stabilization phase (i.e., several months of adherence to medications, opioid abstinence, and other clinical indicators of stability). Side effects of buprenorphine may not have much salience when patients are struggling for survival and safety, but for those who are fortunate enough to advance in their recovery, the side effects become more problematic and can limit quality of life and adherence.

Development and Verification of a Full Physiologically Based Pharmacokinetic Model for Sublingual Buprenorphine in Healthy Adult Volunteers that Accounts for Nonlinear Bioavailability

Sublingual buprenorphine is used for opioid use disorder and neonatal opioid withdrawal syndrome. The study aimed to develop a full physiologically based pharmacokinetic (PBPK) model that can adequately describe dose- and formulation-dependent bioavailability of buprenorphine. Simcyp (v21.0) was used for model construction. Four linear regression models (i.e., untransformed or log transformed for dose or proportion sublingually absorbed) were explored to describe sublingual absorption of buprenorphine across dose. Published clinical trial data not used in model development were used for verification. The PBPK model's predictive performance was deemed adequate if the geometric means of ratios between predicted and observed (P/O) area under the curve (AUC), peak concentration (Cmax), and time to reach Cmax (Tmax) fell within the 1.25-fold prediction error range. Sublingual buprenorphine absorption was best described by a regression model with logarithmically transformed dose. By integrating this nonlinear absorption profile, the PBPK model adequately predicted buprenorphine pharmacokinetics (PK) following administration of sublingual tablets and solution across a dose range of 2-32 mg, with geometric mean (95% confidence interval) P/O ratios for AUC and Cmax equaling 0.99 (0.86-1.12) and 1.24 (1.09-1.40), respectively, and median (5th to 95th percentile) for Tmax equaling 1.11 (0.69-1.57). A verified PBPK model was developed that adequately predicts dose- and formulation-dependent buprenorphine PK following sublingual administration. SIGNIFICANCE STATEMENT: The physiologically based pharmacokinetic (PBPK) model developed in this study is the first to adequately predict dose- and formulation-dependent sublingual buprenorphine pharmacokinetics. Accurate prediction was facilitated by the incorporation of a novel nonlinear absorption model. The developed model will serve as the foundation for maternal-fetal PBPK modeling to predict maternal and fetal buprenorphine exposures to optimize buprenorphine treatment for neonatal opioid withdrawal syndrome.

Comparative evaluation of craving, sleep quality, sexual function and quality of life in opioid use disorder patients in remission with buprenorphine/naloxone maintenance treatment

AIM

To compare opioid use disorder (OUD) patients who continue to use opioids and are in remission with buprenorphine-naloxone (B/N) in terms of some parameters and to evaluate the relationship between B/N dose and these parameters.

METHOD

We included 141 OUD patients in remission with B/N maintenance treatment for at least 6 months, 141 who still used opioids, and 141 healthy volunteers. Substance Craving Scale (SCS), Pittsburgh Sleep Quality Index (PSQI), Arizona Sexual Experiences Scale (ASEX), and Short Form 36 (SF-36) were administered.

RESULTS

PSQI scores and ASEX scores were higher in those who continued to use opiates than in OUD in remission, and in OUD in remission compared to controls. OUD patients with current opioid use also had lower SF-36 scores compared to both patients in remission and healthy controls. SCS, PSQI, ASEX, and SF-36 scores were similar when the three groups were examined based on the dosage of B/N (below 8, 8-15, and 16 mg/day and above) use in OUD in remission.

CONCLUSIONS

Quality of life, craving, sleep and sexual functions improved significantly with B/N; however, these effects are not dependent on B/N dosage.

Pharmacokinetic-pharmacodynamic analysis of drug liking blockade by buprenorphine subcutaneous depot (CAM2038) in participants with opioid use disorder

Buprenorphine is used to treat opioid use disorder (OUD). Weekly and monthly subcutaneous long-acting buprenorphine injections (CAM2038) provide more stable buprenorphine plasma levels and reduce the treatment burden, misuse, and diversion associated with sublingual transmucosal buprenorphine formulations. To characterize the pharmacokinetic/pharmacodynamic (PK/PD) relationship, a maximum inhibition (Imax) model was developed relating CAM2038 buprenorphine plasma concentration to drug liking maximum effect (Emax) visual analog scale (VAS; bipolar) score after intramuscular hydromorphone administration. Data included time-matched observations of buprenorphine plasma concentration and drug liking Emax VAS score after hydromorphone 18 mg administration in 47 non-treatment-seeking adults with moderate to severe OUD in a phase 2 study. Analysis used non-‍linear mixed-effects modeling (NONMEM®). The final Imax model adequately described the PK/PD relationship between buprenorphine plasma concentration and drug liking Emax VAS score. Simulations showed drug liking was effectively blocked at low buprenorphine plasma concentrations (0.4 ng/mL) where the upper 95% confidence interval of the drug liking Emax VAS score was below the pre-defined 11-point complete blockade threshold. The buprenorphine plasma concentration required to achieve 90% of the maximal effect (IC90) of drug liking was 0.675 ng/mL. Interindividual variability in responses to buprenorphine was observed; some participants experienced fluctuating responses, and a few did not achieve drug liking blockade even with higher buprenorphine plasma concentrations. This affirms the need to individualize treatment and titrate doses for optimal treatment outcomes. PK/PD models were also developed for desire to use VAS and Clinical Opiate Withdrawal Scale (COWS) scores, with results aligned to those for drug liking.

Case report: Successful induction of buprenorphine in medically complex patients concurrently on opioids: a case series at a tertiary care center

Effective pain management is essential for optimal surgical outcomes; however, it can be challenging in patients with a history of opioid use disorder (OUD). Buprenorphine, a partial opioid agonist, is a valuable treatment option for patients with OUD. Initiating buprenorphine treatment in patients concurrently taking opioids can be complex due to potential adverse outcomes like precipitated withdrawal. Evolving guidelines suggest there are benefits to continuing buprenorphine for surgical patients throughout the perioperative period, however situations do arise when buprenorphine has been discontinued. Typically, in this scenario patients would be restarted on buprenorphine after they have fully recovered from post-surgical pain and no longer require opioids for pain control. Unfortunately, holding MOUD may expose the patient to risks such as opioid induced respiratory depression or addiction relapse. In this case series, we discuss a novel method to restart buprenorphine in small incremental doses, known as micro-dosing, while the patient is still taking opioids for pain. We will present two complex clinical cases when this method was used successfully at a tertiary care hospital system.

Considerations and limitations of buprenorphine prescribing for opioid use disorder in the intensive care unit setting: A narrative review

PURPOSE

The purpose of this review is to discuss important considerations when prescribing buprenorphine for opioid use disorder (OUD) in the intensive care unit (ICU) setting, recognizing the challenges of providing detailed recommendations in the setting of limited available evidence.

SUMMARY

Buprenorphine is a partial mu-opioid receptor agonist that is likely to be increasingly prescribed for OUD in the ICU setting due to the relaxation of prescribing regulations. The pharmacology and pharmacokinetics of buprenorphine are complicated by the availability of several formulations that can be given by different administration routes. There is no single optimal dosing strategy for buprenorphine induction, with regimens ranging from very low-dose to high dose regimens. Faster induction with higher doses of buprenorphine has been studied and is frequently utilized in the emergency department. In patients admitted to the ICU who were receiving opioids either medically or illicitly, analgesia will not occur until their baseline opioid requirements are covered when their preadmission opioid is either reversed or interrupted. For patients in the ICU who are not on buprenorphine at the time of admission but have possible OUD, there are no validated tools to diagnose OUD or the severity of opioid withdrawal in critically ill patients unable to provide the subjective components of instruments validated in outpatient settings. When prescribing buprenorphine in the ICU, important issues to consider include dosing, monitoring, pain management, use of adjunctive medications, and considerations to transition to outpatient therapy. Ideally, addiction and pain management specialists would be available when buprenorphine is prescribed for critically ill patients.

CONCLUSION

There are unique challenges when prescribing buprenorphine for OUD in critically ill patients, regardless of whether they were receiving buprenorphine when admitted to the ICU setting for OUD or are under consideration for buprenorphine initiation. There is a critical need for more research in this area.

Management of Critically Ill Patients Receiving Medications for Opioid Use Disorder

TOPIC IMPORTANCE

Critical care clinicians are likely to see an increasing number of patients admitted to the ICU who are receiving US Food and Drug Administration-approved medications for opioid use disorder (MOUDs) given the well-documented benefits of these agents. Oral methadone, multiple formulations of buprenorphine, and extended-release naltrexone are the three types of MOUD most likely to be encountered by ICU clinicians; however, these drugs vary with respect to formulations, pharmacokinetics, and adverse effects.

REVIEW FINDINGS

No published clinical practice guidelines or consensus statements are available to guide decision-making in patients admitted to the ICU setting who are receiving MOUDs before admission. Additionally, no randomized trials and limited observational studies have evaluated issues related to MOUD use in the ICU. Therefore, ICU clinicians caring for patients admitted who are taking MOUDs must base their decision-making on data extrapolation from pharmacokinetic, pharmacologic, and clinical studies performed in non-ICU settings.

SUMMARY

Despite the challenges in administering MOUDs in critically ill patients, extrapolation of data from other hospital settings suggests that the benefits of continuing MOUD therapy outweigh the risks in patients able to continue therapy. This article provides guidance for critical care clinicians caring for patients admitted to the ICU already receiving methadone, buprenorphine, or extended-release naltrexone. The guidance includes algorithms to aid clinicians in the clinical decision-making process, recognizing the inherent limitations of the existing evidence on which the algorithms are based and the need to account for patient-specific considerations.

Buprenorphine and methadone differentially alter early brain development in human cortical organoids

Buprenorphine (BUP) and methadone (MTD) are used for medication-assisted treatment (MAT) in opioid use disorder. Although both medications show improved maternal and neonatal outcomes compared with illicit opioid use during pregnancy, BUP has exhibited more favorable outcomes to newborns than MTD. The underlying cellular and molecular mechanisms for the difference between BUP and MTD are largely unknown. Here, we examined the growth and neuronal activity in human cortical organoids (hCOs) exposed to BUP or MTD. We found that the growth of hCOs was significantly restricted in the MTD-treated but not in the BUP-treated hCOs and BUP attenuated the growth-restriction effect of MTD in hCOs. Furthermore, a κ-receptor agonist restricted while an antagonist alleviated the growth-restriction effect of MTD in hCOs. Since BUP is not only a μ-agonist but a κ-antagonist, the prevention of this growth-restriction by BUP is likely due to its κ-receptor-antagonism. In addition, using multielectrode array (MEA) technique, we discovered that both BUP and MTD inhibited neuronal activity in hCOs but BUP showed suppressive effects only at higher concentrations. Furthermore, κ-receptor antagonist nBNI did not prevent the MTD-induced suppression of neuronal activity in hCOs but the NMDA-antagonism of MTD (that BUP lacks) plays a role in the inhibition of neuronal activity. We conclude that, although both MTD and BUP are μ-opioid agonists, a) the additional κ-receptor antagonism of BUP mitigates the MTD-induced growth restriction during neurodevelopment and b) the lack of NMDA antagonism of BUP (in contrast to MTD) induces much less suppressive effect on neural network communications.

Population Pharmacokinetic Analysis Supports Initiation Treatment and Bridging from Sublingual Buprenorphine to Subcutaneous Administration of a Buprenorphine Depot (CAM2038) in the Treatment of Opioid Use Disorder

BACKGROUND AND OBJECTIVE

In treating opioid use disorder (OUD), subcutaneous (SC) extended-release buprenorphine (BPN) depots, e.g., CAM2038, have been shown to provide smaller and less frequent fluctuations in BPN plasma concentrations and pharmacodynamic responses, improve outcomes, reduce treatment burden, and lower risks of misuse and diversion compared to daily sublingual (SL) BPN. This analysis characterized the pharmacokinetics (PK) of BPN following intravenous and SL administration, and administration of SC CAM2038 weekly and monthly.

METHODS

Pharmacokinetic data from two Phase 1 and two Phase 2 trials in healthy participants and participants with OUD, respectively, were used to develop a population PK model using non-linear mixed effects modelling. The analysis included data from 252 participants and 10,658 BPN observations.

RESULTS

The disposition of BPN was best described by a three-compartment model with first-order elimination, and absorption of SL BPN and SC CAM2038 weekly and monthly by dual parallel absorption pathways. Model diagnostics indicated good predictive performance of BPN concentrations. Buprenorphine plasma concentration-time profiles were simulated for treatment initiation, switching from SL BPN to CAM2038 weekly and monthly, and tapering after interrupting treatment with CAM2038. Simulations predicted CAM2038 weekly and monthly doses that provided BPN plasma maximum concentration (Cmax) and trough concentration (Ctrough) values at steady state within those observed following SL BPN administration.

CONCLUSIONS

This population PK model supports the use of CAM2038 doses as individualized treatment for OUD across different treatment stages, including initiation, switching from SL BPN according to established dose conversion schedules, and tapering.

TRIAL REGISTRATIONS

ISRCTN41550730 (05/19/2014), ISRCTN24987553 (07/29/2014), NCT02611752 (11/23/2015), NCT02710526 (03/16/2016).

Associations of methadone and buprenorphine-naloxone doses with unregulated opioid use, treatment retention, and adverse events in prescription-type opioid use disorders: Exploratory analyses of the OPTIMA study

BACKGROUND AND OBJECTIVES

Buprenorphine/naloxone (BUP-NX) and methadone are used to treat opioid use disorder (OUD), yet there is insufficient evidence on the impact of doses on interventions' effectiveness and safety when treating OUD attributable to other opioids than heroin.

METHODS

We explored associations between methadone and BUP-NX doses and treatment outcomes using data from OPTIMA, a 24-week, pragmatic, open-label, multicenter, pan-Canadian, randomized controlled, two-arm parallel trial with participants (N = 272) with OUD who primarily use opioids other than heroin. Participants were randomized to receive flexible take-home BUP-NX (n = 138) or standard supervised methadone treatment (n = 134). We examined associations between highest BUP-NX and methadone doses, and (1) percentage of opioid-positive urine drug screens (UDS); (2) retention in the assigned treatment; and (3) adverse events (AEs).

RESULTS

The mean (SD) highest BUP-NX and methadone dose were 17.31 mg/day (8.59) and 67.70 mg/day (34.70). BUP-NX and methadone doses were not associated with opioid-positive UDS percentages or AEs. Methadone dose was associated with higher retention in treatment (odds ratio [OR]: 1.025; 95% confidence interval [CI]: 1.010; 1.041), while BUP-NX dose was not (OR: 1.055; 95% CI: 0.990; 1.124). Higher methadone doses (70-110 mg/day) offered higher odds of treatment retention.

DISCUSSION AND CONCLUSION

Methadone dose was associated with higher retention, which may be related to its full µ-opioid receptor agonism. Future research should notably ascertain the effect of pace of titration on a wide range of outcomes.

SCIENTIFIC SIGNIFICANCE

Our results extend previous findings of high doses of methadone increasing retention to be applied in our population using opioids other than heroin, including highly potent opioids.

Rapid Low-dose Buprenorphine Initiation for Hospitalized Patients With Opioid Use Disorder

INTRODUCTION

Low-dose buprenorphine initiation allows patients to start buprenorphine for treatment of opioid use disorder (OUD) while continuing full-agonist opioids. This strategy is beneficial for hospitalized patients who may have acute pain and are not able to tolerate withdrawal. However, most protocols require 7-10 to complete, which may create barriers in patients with shorter or unpredictable lengths of stay.

OBJECTIVE

This cohort study examined the efficacy and feasibility of a rapid low-dose buprenorphine initiation protocol in the hospital setting.

METHODS

We performed a retrospective cohort study of hospitalized patients with OUD (diagnosed by DSM-5 criteria) seen by an addiction medicine consult service at a single academic medical center who started buprenorphine via a rapid low-dose initiation between November 2021 and May 2022. Patients were prospectively tracked using an electronic registry, and data were abstracted from the electronic health record.

RESULTS

Twenty-four patients underwent rapid low-dose initiation during the study period. All patients received full-agonist opioids before starting buprenorphine. Thirteen (54%) patients reported using fentanyl, with 5 patients reported endorsing use within 48 hours preceding buprenorphine initiation. Nineteen (79%) patients completed initiation with an average time to completion of 72 hours. Among patients who reported fentanyl use in the 48 hours before starting buprenorphine, 60% completed initiation and 40% elected to transition to methadone. No patients experienced precipitated withdrawal.

CONCLUSIONS

Rapid low-dose buprenorphine initiation provides a feasible and well-tolerated alternative to traditional and slower low-dose initiations for hospitalized patients.

Eliminate the buprenorphine DEA X waiver: Justification using a policy analysis approach

INTRODUCTION

Drug overdoses have reached a historic milestone of over 100,000 deaths in a single year, 75,673 related to opioids. The acceleration in opioid-related deaths coupled with stark health inequities demands a close examination of opioid use disorder (OUD) treatment barriers and swift consideration of policy changes.

DESIGN

The aim of this buprenorphine policy analysis is to summarize existing buprenorphine barriers and present policy solutions to improve access and actualize the contributions of Advanced Practice Registered Nurses (APRNs).

METHODS

The policy analysis follows five sequential steps: (1) defining the problem, (2) identifying key stakeholders, (3) assessing the landscape of relevant policies, (4) describing viable policy options, and (5) making final recommendations.

RESULTS

Although there are laudable efforts to improve buprenorphine access, such as the new buprenorphine guidelines issued in April 2021, without larger-scale changes to federal, state, and scope of practice laws, overdose rates will continue to rise. We recommend a multipronged policy approach to improve buprenorphine treatment access, including eliminating the DEA X waiver, improving OUD education, and adopting full practice authority for APRNs in all states.

CONCLUSION

Incremental change is no longer sufficient to address opioid overdose deaths. Bolder and coordinated policy action is possible and necessary to empower the full clinical workforce to apply evidence-based life-saving treatments for OUD. The critical contributions of nurses in advancing equitable access to OUD care are emphasized in the National Academy of Medicine's Report, Future of Nursing: Charting a Path to Achieve Health Equity. Nurses are named as instrumental in improving buprenorphine access. Policy changes that acknowledge and build on evidence-based treatment expansion strategies are sorely needed.

CLINICAL RELEVANCE

One of the most robust tools to combat opioid overdose deaths is buprenorphine, a partial opioid agonist, and gold standard medication treatment for OUD, but only 5% of the prescribing workforce possess the required Drug Enforcement Agency (DEA) X waiver. A growing body of evidence demonstrates that Advanced Practice Registered Nurses are accelerating the growth in waiver update and buprenorphine use, despite the considerable barriers and limitations described in this policy analysis.

Facilitating factors and barriers for use of medications to treat opioid use disorder (MOUD) among justice-involved individuals in rural Appalachia

The purpose of this qualitative study is to assess facilitating factors and barriers for medications to treat opioid use disorder (MOUD) initiation among justice-involved individuals in one rural Appalachian community, as well as how those factors may differ across the three types of Food and Drug Administration (FDA) approved medications. Qualitative interviews were conducted with rural justice-involved individuals (N = 10) with a history of opioid use in the target community. Overall, participants demonstrated knowledge of the different types of MOUD and their pharmacological properties, but limited overall health literacy around opioid use disorder and MOUD treatment. Treatment access was hampered by transportation, time burdens, and costs. Findings call for research into improving health literacy education, training, and resources to decrease stigma and increase access to MOUD, particularly in light of the ongoing opioid crisis. State policies also need to increase access to all FDA medications among justice-involved individuals, as well as supporting a care continuum from facility entry, release, and community re-entry.

Sublingual buprenorphine/naloxone treatment is not affected by OPRM1 A118G and BDNF Va66Met polymorphisms, but alters the plasma beta-endorphin and BDNF levels in individuals with opioid use disorder

The study aimed to examine the genetic contribution to buprenorphine (BUP) treatment in individuals with opioid use disorder (OUD), with a specific focus on BDNF and OPRM1 genes. A total of 113 controls and 111 OUD patients receiving sublingual BUP/naloxone were enrolled. OPRM1 A118G and BDNF Val66Met polymorphisms were investigated by PCR-FRLP. Plasma BDNF and beta-endorphin levels were assessed by ELISA kits in both groups. Blood BUP levels were measured by LC-MS/MS and normalized with daily BUP dose (BUP/D). OPRM1 A118G and BDNF Val66Met polymorphisms didn't have an effect on plasma beta-endorphin and BDNF levels in OUD patients, respectively. Interestingly, OUD patients had significantly higher plasma BDNF and lower beta-endorphin levels compared to the controls (p < 0.001). A negative and significant correlation between plasma BUP/D and BDNF levels was found. Age onset of first use was associated with OPRM1 A118G polymorphism. The findings indicated that sublingual BUP/naloxone may increase plasma BDNF levels, but may decrease beta-endorphin levels in individuals with OUD. Plasma BDNF level seemed to be decreased in a BUP/D concentration-dependent manner.

Lower buprenorphine elimination rate constant is associated with lower opioid use

BACKGROUND

Opioid craving is suggested to correlate with the rate of reduction in buprenorphine (BUP) plasma levels. No studies explored Buprenorphine elimination rate constant (BUP EL.R) as a predictor of opioid use or retention in BUP treatment.

METHODS

Analysis was performed using data from a randomized controlled trial of 141 adults with opioid use disorder (OUD) randomized to Incentivized Adherence and Abstinence monitoring (I-AAM; experimental (n = 70) and treatment-as-usual; control (n = 71). In the I-AAM, structured access to unsupervised BUP doses was provided up to 28 days contingent of adherence measured by Therapeutic Drug Monitoring and abstinence by Urinary Drug Screens (UDS). In contrast, the treatment-as-usual (control) provided unstructured access to unsupervised doses was provided for up to 14 days considering UDS results. The primary outcome was percentage negative UDS. The secondary outcome, retention in treatment, was continuous enrollment in the study and analysis was via intention-to-treat. Significant bivariate correlations with the outcomes were adjusted for group allocation.

RESULTS

A significant negative correlation between BUP EL.R and percentage negative opioid screens (Pearson correlation coefficient - 0.57, p < 0.01) was found. After adjusting for trial group, BUP EL.R was shown to be an independent predictor of percentage negative opioid screens (Standardized Beta Coefficient - 0.57, 95% CI - 221.57 to - 97.44, R² 0.322).

CONCLUSION

BUP EL.R predicted 32.2% of the variation in percentage negative opioid UDS and may serve as a potential promising tool in precision medicine of BUP treatment. Higher buprenorphine elimination is associated with higher positive opioid urine screens during treatment.

TRIAL REGISTRATION

ISRCTN41645723 retrospectively registered on 15/11/2015.

Associations of retention on buprenorphine for opioid use disorder with patient characteristics and models of care in the primary care setting

INTRODUCTION

Buprenorphine, a medication for opioid use disorder (OUD), can be administered within primary care; however, little is known about characteristics associated with retention on buprenorphine in these settings. This study examines patient correlates of buprenorphine retention and whether an integrated, interdisciplinary treatment model (buprenorphine and behavioral health) is associated with higher odds of buprenorphine retention than a primarily medication-only treatment model.

METHODS

Electronic health record data from adult patients with an OUD, ≥1 buprenorphine order and ≥1 visit to either of two primary care clinics between 9/2/2014-6/27/2018 were extracted (N = 494 patients). Two research team members reviewed the medication start and stop dates for each buprenorphine order and classified as retained (≥6 months of orders) or not retained (<6 months of orders). Logistic regressions estimated the odds of retention on buprenorphine by 1) patient characteristics and 2) timing of patient's engagement in buprenorphine treatment (pre- or post-implementation of an integrated treatment model).

RESULTS

Of the study sample, 53% had ≥6 months of buprenorphine orders. Almost two times higher odds of retention were found among patients with ≥1 psychiatric comorbidity (versus none) and among those with buprenorphine orders in the post- versus pre-period.

CONCLUSIONS

An integrated, interdisciplinary model of OUD treatment was associated with ≥6 months of buprenorphine orders among our study population. Continued research is needed in real-world primary care settings to understand the impact of OUD treatment models on patient outcomes. A more nuanced examination of the associations between psychiatric diagnoses and buprenorphine treatment retention is warranted.

Novel Long-Acting Buprenorphine Medications for Opioid Dependence: Current Update

Opioid maintenance treatment with oral methadone or sublingual buprenorphine is the first-line treatment in opioid dependence. Three novel long-acting buprenorphine formulations have been approved or will be available soon: for subcutaneous weekly and monthly application, the depot formulations CAM 2038 (Buvidal^®), the monthly depot formulation RBP-6000 (Sublocade™), and a 6-month buprenorphine implant (Probuphine™). Clinical data available so far on the efficacy of these 3 medications are given, and possible clinical implications are discussed.