Is Buprenorphine Effective for Chronic Pain? A Systematic Review and Meta-analysis

The current state of knowledge on care for co-occurring chronic pain and opioid use disorder: A scoping review

BACKGROUND AND AIMS

Opioid use disorder often co-occurs with chronic pain but assessment and treatment of these co-occurring disorders is complex. This review aims to identify current treatments and delivery models for co-occurring chronic pain and opioid use disorder (OUD) documented in the scientific literature.

DESIGN

Scoping review.

METHODS

The review was conducted in six databases in June 2022 (no time limit): CINAHL, PsycINFO, Web of Science, Cochrane, PubMed and Embase. The PRISMA-ScR checklist was used to guide reporting.

RESULTS

Forty-seven publications addressing the issue of co-occurring chronic pain and OUD management were included. Randomized controlled trials provide evidence for the effectiveness of opioid agonist treatments (OAT) such as methadone or buprenorphine/naloxone, as well as for combining OAT with Mindfulness-Oriented Recovery Enhancement or cognitive behavioural therapy. A number of other pharmacological treatments (opioid and nonopioid), nonpharmacological treatments (e.g. physiotherapy) and service delivery models (e.g. simultaneous treatment of comorbidities, interdisciplinary and interprofessional collaboration) are also underlined. In most cases, authors recommend a combination of strategies to meet patient needs.

CONCLUSIONS

The scoping review reveals gaps in evidence-based knowledge to effectively care for co-occurring chronic pain and OUD, but several experts recommend the uptake of known 'best' practices such as integrated treatment of the multiple biopsychosocial dimensions of the co-occurring disorders as well as collaborative interdisciplinary work.

CLINICAL RELEVANCE

Improving services is dependent on alleviating barriers such as working in silos, the costs associated with nonpharmacological treatments, and the double stigma associated with pain in people with a substance use disorder.

Mental Health Distress Is Associated With Higher Pain Interference in Patients With Opioid Use Disorder Stabilized on Buprenorphine or Methadone

BACKGROUND

The relationships between opioid use disorder (OUD), chronic pain, and mental health distress are complex and multidirectional. The objective of this exploratory study was to examine the relationship between mental health conditions and Chronic pain severity and interference among patients stabilized on either buprenorphine or methadone.

METHODS

We report baseline data from a randomized trial of a mind-body intervention conducted at 5 outpatient clinics that provided either buprenorphine or methadone treatment. Validated scales were used to measure substance use, mental health distress, and pain severity and interference. Statistical analyses examined the relationship between mental health conditions and pain severity and interference.

RESULTS

Of 303 participants, 57% (n = 172) reported Chronic pain. A total of 88% (n = 268) were prescribed buprenorphine. Mental health conditions were common, with one-quarter of the sample screening positive for all 3 mental health conditions (anxiety, depression, and posttraumatic stress disorder [PTSD]). Compared to participants without Chronic pain, participants with Chronic pain were more likely to screen positive for moderate-severe anxiety (47% vs 31%); moderate-severe depression (54% vs 41%); and the combination of anxiety, depression, and PTSD (31% vs 18%). Among participants with Chronic pain, mental health conditions were associated with higher pain interference. Pain severity was higher among participants with mental health conditions, but only reached statistical significance for depression. Pain interference scores increased with a higher number of co-occurring mental health conditions.

CONCLUSIONS

Among individuals stabilized on either buprenorphine or methadone, highly symptomatic and comorbid mental health distress is common and is associated with increased pain interference. Adequate screening for, and treatment of, mental health conditions in patients with OUD and Chronic pain is needed.

Neuropsychiatric Effects Associated with Opioid-Based Management for Palliative Care Patients

PURPOSE OF REVIEW

The abundance of opioids administered in the palliative care setting that was once considered a standard of care is at present necessitating that providers evaluate patients for unintentional and deleterious symptomology related to aberrant opioid use and addiction. Polypharmacy with opioids is dynamic in affecting patients neurologically, and increased amounts of prescriptions have had inimical effects, not only for the individual, but also for their families and healthcare providers. The purpose of this review is to widen the perspective of opioid consequences and bring awareness to the numerous neuropsychiatric effects associated with the most commonly prescribed opioids for patients receiving palliative care.

RECENT FINDINGS

Numerous clinical and research studies have found evidence in support for increased incidence of opioid usage and abuse as well as undesirable neurological outcomes. The most common and concerning effects of opioid usage in this setting are delirium and problematic drug-related behavioral changes such as deceitful behavior towards family and physicians, anger outbursts, overtaking of medications, and early prescription refill requests. Other neuropsychiatric effects detailed by recent studies include drug-seeking behavior, tolerance, dependence, addictive disorder, anxiety, substance use disorder, emotional distress, continuation of opioids to avoid opioid withdrawal syndrome, depression, and suicidal ideation. Opioid usage has detrimental and confounding effects that have been overlooked for many years by palliative care providers and patients receiving palliative care. It is necessary, even lifesaving, to be cognizant of potential neuropsychiatric effects that opioids can have on an individual, especially for those under palliative care. By having an increased understanding and awareness of potential opioid neuropsychiatric effects, patient quality of life can be improved, healthcare system costs can be decreased, and patient outcomes can be met and exceeded.

Study Protocol for Pain Self-Management and Patient-Oriented Buprenorphine Dosing for Pain and Retention in Office-Based Opioid Treatment: A Hybrid Type 1, 2 × 2 Factorial Randomized Controlled Trial

Chronic pain is a significant factor for patients with opioid use disorder (OUD) contributing to suboptimal retention in buprenorphine treatment, which is a crucial predictor of long-term health outcomes. This study aims to address the critical need for effective interventions targeting chronic pain management within office-based opioid treatment (OBOT) programs. We are conducting a multisite, hybrid type 1, 2 × 2 factorial randomized clinical trial to determine the effectiveness of 2 novel interventions, pain self-management (PSM) and patient-oriented buprenorphine dosing (POD), to decrease pain interference and improve retention in buprenorphine treatment. PSM, a manualized and customizable approach delivered through individual and peer-led group sessions, aims to decrease pain-related symptoms and quality of life. POD involves split dosing of buprenorphine to extend the duration of analgesia to better match its duration of efficacy at managing OUD symptoms, leading to improved retention in buprenorphine treatment. Eligible participants will be randomized into 1 of 4 groups: (1) PSM + POD, (2) PSM + Standard Buprenorphine Dosing, (3) Usual Care + POD, or (4) Usual Care + Standard Buprenorphine Dosing. Usual Care refers to usual care for chronic pain and Standard Buprenorphine Dosing refers to the participant's current dosing regimen. Secondary objectives encompass overall pain reduction, decreased opioid use, improved pain symptom management, and exploration of implementation strategies. The supplemental approved protocol provides comprehensive insights into the procedures and variables being investigated. As part of the HEAL Initiative®-funded Integrative Management of Chronic Pain and OUD for Whole Recovery (IMPOWR) network, this study aims to fill gaps in behavioral and medication treatments for individuals with co-occurring chronic pain and OUDs, improving pain management and retention in care. Successful outcomes from this trial may inform future larger trials, offering essential evidence for implementation considerations and reimbursement decisions.

Long-acting injectable buprenorphine in the real world: case report on dual disorders

OBJECTIVES

Long-acting injectable buprenorphine (LAIB) has demonstrated a good profile for opioid use disorder (OUD) management. However, there is scarce information on LAIB in OUD patients with comorbid mental disorders (dual disorder patients).

METHODS

We present a case report on OUD patients with a comorbid mental disorder who have received LAIB for at least 3 months.

RESULTS

Two women and one man with OUD and another comorbid mental disorder were prescribed with LAIB ranging from three to twelve months. Good adherence and opioid abstinence were observed during the follow-up. Psychopathological issues related to comorbid mental disorders were stabilized. A deep discussion on LAIB in this profile of patients is conducted.

CONCLUSIONS

LAIB in OUD patients with comorbid mental disorders may be a safe and well tolerated option, similar to OUD patients without comorbid mental disorders. LAIB's impact on psychopathological issues requires further high-quality research to understand the real impact of LAIB on OUD and comorbid mental disorders.

Buprenorphine for Pain: A Narrative Review and Practical Applications

Chronic noncancer pain affects about 20% of US adults and can significantly affect function and quality of life. Current guidelines recommend multimodal pain control. Despite risks associated with long-term opioid therapy, opioids are commonly prescribed. Buprenorphine is a partial opioid agonist with an improved safety profile compared to full agonists. Some formulations are approved for chronic pain and others for opioid use disorder. Buprenorphine is an option for patients who use chronic daily opioids for pain. This review summarizes the literature on buprenorphine's efficacy and safety for chronic pain and provides recommendations to generalists on initiation, titration, and monitoring of buprenorphine-based pain treatment. We also discuss a communication approach when considering buprenorphine for pain.

Denial of prescription pain medication among people who use drugs in Vancouver, Canada

BACKGROUND

People who use drugs experience pain at two to three times the rate of the general population and yet continue to face substantial barriers to accessing appropriate and adequate treatment for pain. In light of the overdose crisis and revised opioid prescribing guidelines, we sought to identify factors associated with being denied pain medication and longitudinally investigate denial rates among people who use drugs.

METHODS

We used multivariable generalized estimating equations analyses to investigate factors associated with being denied pain medication among people who use drugs reporting pain in three prospective cohort studies in Vancouver, Canada. Analyses were restricted to study periods in which participants requested a prescription for pain from a healthcare provider. Descriptive statistics detail denial rates and actions taken by participants after being denied.

RESULTS

Among 1168 participants who requested a prescription for pain between December 2012 and March 2020, the median age was 47 years and 63.0% were male. Among 4,179 six-month observation periods, 907 (21.7%) included a report of being denied requested pain medication. In multivariable analyses, age was negatively associated with prescription denial (adjusted odds ratio [AOR] = 0.98, 95% confidence interval [CI]:0.97-0.99), while self-managing pain (AOR = 2.48, 95%CI:2.04-3.00), experiencing a non-fatal overdose (AOR = 1.51, 95%CI:1.22-1.88), engagement in opioid agonist therapy (AOR = 1.32, 95%CI:1.09-1.61), and daily use of heroin or other unregulated opioids (AOR = 1.32, 95%CI:1.05-1.66) were positively associated with being denied. Common actions taken (n = 895) after denial were accessing the unregulated drug supply (53.5%), doing nothing (30.6%), and going to a different doctor/emergency room (6.1%). The period following the introduction of new prescribing guidelines was not associated with a change in denial rates.

CONCLUSIONS

A substantial proportion of people who use drugs continue to be denied prescriptions for pain, with such denial associated with important substance use-related harms, including non-fatal overdose. Guidelines specific to the pharmaceutical management of pain among people who use drugs are needed.

Buprenorphine for Chronic Pain Management: a Narrative Review

PURPOSE OF REVIEW

The aim of this review is to educate healthcare professionals regarding buprenorphine for the use of opioid use disorder (OUD) as well as for chronic pain management. This review provides physicians and practitioners with updated information regarding the distinct characteristics and intricacies of prescribing buprenorphine.

RECENT FINDINGS

Buprenorphine is approved by the US Food and Drug Administration (FDA) for acute pain, chronic pain, opioid use disorder (OUD), and opioid dependence. When compared to most other opioids, buprenorphine offers superior patient tolerability, an excellent half-life, and minimal respiratory depression. Buprenorphine does have notable side effects as well as pharmacokinetic properties that require special attention, especially if patients require future surgical interventions. Many physicians are not trained to initiate or manage patients on buprenorphine. However, buprenorphine offers a potentially safer alternative for medication management for patients who require chronic opioid therapy for pain or have OUD. This review provides updated information on buprenorphine for both chronic pain and OUD.

Outpatient cross-titration to buprenorphine for chronic pain: A retrospective analysis

OBJECTIVE

To determine the effectiveness and safety of the University of Washington's buprenorphine cross-titration protocol for chronic pain in the outpatient setting.

METHODS

Retrospective chart review was performed on 150 patients transitioned from full µ-opioid agonist therapy to buprenorphine using the University of Washington Medical Center Pain Clinic's cross-titration protocol between September 1, 2020, and December 31, 2021, in an outpatient setting. Primary outcome was to determine the percentage of patients who completed the cross-titration and continued buprenorphine without full µ-opioid agonists 4 weeks after completion. Secondary outcomes included final buprenorphine dose, days needed to complete cross-titration, deviation rates from the protocol, and opioid-related adverse events.

RESULTS

Fifteen of 31 (48.4 percent) included patients successfully converted to buprenorphine. Median duration of successful cross-titration was 29 days (interquartile range 19-57). Average end-titration dose for patients on buprenorphine/naloxone sublingual films was 7.9 ± 5.7 mg/day, while for buprenorphine transdermal (TD) patches, it was 11.9 ± 4.8 mcg/h. Morphine equivalent daily dose (MEDD) prior to induction varied widely. All patients transitioned to TD buprenorphine were taking ≤30 mg MEDD. Patients previously taking >120 mg MEDD stabilized on 8-16 mg/day buprenorphine. Most common reasons for cross-titration failure were inadequate pain control and intolerable adverse effects.

DISCUSSION

The University of Washington's buprenorphine cross-titration protocol for chronic pain was successful in about half of included patients undergoing conversion from chronic full µ-opioid agonist therapy and generally well tolerated. Clinical responses were widely variable, and many required slower taper and higher end-titration buprenorphine dose than anticipated. Although protocols provide structure for cross-titration, each course should be monitored closely and individualized.

Analgesic Effect of Buprenorphine for Chronic Noncancer Pain: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Buprenorphine is a partial agonist at the µ-opioid receptor and an antagonist at the delta and kappa opioid receptors. It has high affinity and low intrinsic activity at the µ-opioid receptor. Buprenorphine demonstrates no ceiling effect for clinical analgesia, but demonstrates this for respiratory depression and euphoria. It may provide effective analgesia while producing less adverse effects, making it a promising opioid analgesic. A systematic review and meta-analysis were performed to examine the analgesic efficacy of buprenorphine for patients with chronic noncancer pain.

METHODS

PubMed, MEDLNE, Embase, and the Cochrane Library were searched up to January 2022. Randomized controlled trials were included if they compared buprenorphine versus placebo or active analgesic in patients with chronic noncancer pain, where pain score was an outcome. Nonrandomized controlled trials, observational studies, qualitative studies, case reports, and commentaries were excluded. Two investigators independently performed the literature search, study selection, and data collection. A random-effects model was used. The primary outcome was the effect of buprenorphine on pain intensity in patients with chronic noncancer pain based on standardized mean difference (SMD) in pain score. Quality of evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Two separate literature searches were conducted for patients with and without opioid use disorder (OUD). Only one study met the search criteria for those with OUD. Fourteen randomized controlled trials were included for those without OUD. Buprenorphine was associated with reduced pain score (SMD = -0.368, P < .001, I 2 = 89.37%) compared to placebo or active analgesic. Subgroup meta-analyses showed statistically significant differences in favor of buprenorphine versus placebo (SMD = -0.404, P < .001), for chronic low back pain (SMD = -0.383, P < .001), when administered via the transdermal route (SMD = -0.572, P = .001), via the buccal route (SMD = -0.453, P < .001), with length of follow-up lasting <12 weeks (SMD = -0.848, P < .05), and length of follow-up lasting 12 weeks or more (SMD = -0.415, P < .001). There was no significant difference when compared to active analgesic (SMD = 0.045, P > .05). Quality of evidence was low to moderate.

CONCLUSIONS

Buprenorphine was associated with a statistically significant and small reduction in pain intensity compared to placebo. Both the transdermal and buccal routes provided pain relief. There was more evidence supporting its use for chronic low back pain.

The Use of Opioids in the Management of Chronic Pain: Synopsis of the 2022 Updated U.S. Department of Veterans Affairs and U.S. Department of Defense Clinical Practice Guideline

DESCRIPTION

In May 2022, leadership within the U.S. Department of Veterans Affairs (VA) and U.S. Department of Defense (DoD) approved a joint clinical practice guideline for the use of opioids when managing chronic pain. This synopsis summarizes the recommendations that the authors believe are the most important to highlight.

METHODS

In December 2020, the VA/DoD Evidence-Based Practice Work Group assembled a team to update the 2017 VA/DoD Clinical Practice Guideline for Opioid Therapy for Chronic Pain. The guideline development team included clinical stakeholders and conformed to the National Academy of Medicine's tenets for trustworthy clinical practice guidelines. The guideline team developed key questions to guide a systematic evidence review that was done by an independent third party and distilled 20 recommendations for care using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The guideline team also created 3 one-page algorithms to help guide clinical decision making. This synopsis presents the recommendations and highlights selected recommendations on the basis of clinical relevance.

RECOMMENDATIONS

This guideline is intended for clinicians who may be considering opioid therapy to manage patients with chronic pain. This synopsis reviews updated recommendations for the initiation and continuation of opioid therapy; dose, duration, and taper of opioids; screening, assessment, and evaluation; and risk mitigation. New additions are highlighted, including recommendations about the use of buprenorphine instead of full agonist opioids; assessing for behavioral health conditions and factors associated with higher risk for harm, such as pain catastrophizing; and the use of pain and opioid education to reduce the risk for prolonged opioid use for postsurgical pain.

Primary care management of Long-Term opioid therapy

The United States underwent massive expansion in opioid prescribing from 1990-2010, followed by opioid stewardship initiatives and reduced prescribing. Opioids are no longer considered first-line therapy for most chronic pain conditions and clinicians should first seek alternatives in most circumstances. Patients who have been treated with opioids long-term should be managed differently, sometimes even continued on opioids due to physiologic changes wrought by long-term opioid therapy and documented risks of discontinuation. When providing long-term opioid therapy, clinicians should document opioid stewardship measures, including assessments, consents, medication reconciliation, and offering naloxone, along with the rationale to continue opioid therapy. Clinicians should screen regularly for opioid use disorder and arrange for or directly provide treatment. In particular, buprenorphine can be highly useful for co-morbid pain and opioid use disorder. Addressing other substance use disorders, as well as preventive health related to substance use, should be a priority in patients with opioid use disorder. Patient-centered practices, such as shared decision-making and attending to related facets of a patient's life that influence health outcomes, should be implemented at all points of care.Key messagesAlthough opioids are no longer considered first-line therapy for most chronic pain, management of patients already taking long-term opioid therapy must be individualised.Documentation of opioid stewardship measures can help to organise opioid prescribing and protect clinicians from regulatory scrutiny.Management of resultant opioid use disorder should include provision of medications, most often buprenorphine, and several additional screening and preventive measures.

Evidence based opioid weaning with behavioral support - Forum for Behavioral Science Edition

Nationally published guidelines state that many patients prescribed chronic opioids would benefit from gradually reducing and/or eliminating their use of these medications. This is easier said than done. Patients are often resistant or fearful, physicians are often uncomfortable prescribing an opioid taper, and patients often do not get the needed behavioral health support in this process. It is critical to develop a comprehensive behavioral and medical plan, however the field lacks practical approaches to guide physicians (and patients) through this challenge. In this manuscript our team of primary care providers and behaviorists walk through a case involving complex opioid weaning in a Family Medicine residency clinic environment. Through the lens of our patient's case, we will discuss best practices for getting patient buy-in, opioid weaning strategies, behavioral support during the wean, identifying co-morbid opioid use disorders, and deciding on acceptable end points for the taper.

Current and Future Therapeutic Options in Pain Management: Multi-mechanistic Opioids Involving Both MOR and NOP Receptor Activation

Opioids are widely used in chronic pain management, despite major concerns about their risk of adverse events, particularly abuse, misuse, and respiratory depression from overdose. Multi-mechanistic opioids, such as tapentadol and buprenorphine, have been widely studied as a valid alternative to traditional opioids for their safer profile. Special interest was focused on the role of the nociceptin opioid peptide (NOP) receptor in terms of analgesia and improved tolerability. Nociceptin opioid peptide receptor agonists were shown to reinforce the antinociceptive effect of mu opioid receptor (MOR) agonists and modulate some of their adverse effects. Therefore, multi-mechanistic opioids involving both MOR and NOP receptor activation became a major field of pharmaceutical and clinical investigations. Buprenorphine was re-discovered in a new perspective, as an atypical analgesic and as a substitution therapy for opioid use disorders; and buprenorphine derivatives have been tested in animal models of nociceptive and neuropathic pain. Similarly, cebranopadol, a full MOR/NOP receptor agonist, has been clinically evaluated for its potent analgesic efficacy and better tolerability profile, compared with traditional opioids. This review overviews pharmacological mechanisms of the NOP receptor system, including its role in pain management and in the development of opioid tolerance. Clinical data on buprenorphine suggest its role as a safer alternative to traditional opioids, particularly in patients with non-cancer pain; while data on cebranopadol still require phase III study results to approve its introduction on the market. Other bifunctional MOR/NOP receptor ligands, such as BU08028, BU10038, and AT-121, are currently under pharmacological investigations and could represent promising analgesic agents for the future.

Management of chronic non-cancer pain: a framework

Aim: Since publication of the CDC 2016 Guideline, opioid-related mortality in the USA has doubled and a crisis has developed among the 15-20 million Americans with chronic, moderate-to-severe, noncancer pain. Our aim was to develop a comprehensive alternative approach to management of chronic pain. Methods: Analytic review of the clinical literature. Results: Published science provides a solid framework for the management of chronic non-cancer pain, detailed here, even as it leaves many knowledge gaps, which we fill with insights from clinical experience. Conclusion: There is a sufficient basis in science and in clinical experience to achieve adequate control of chronic pain in nearly all patients in a way that adequately balances benefits and potential harms.

The State-of-the-art Pharmacotherapeutic Options for the Treatment of Chronic Non-Cancer Pain

INTRODUCTION

Pharmacotherapeutic options continue to expand for the treatment of chronic non-cancer pain. There has been an increasing emphasis on multimodal analgesia. This strategy employs use of multiple analgesic medications each with a distinct mechanism of action, which when administered concomitantly may provide profound analgesia.

AREAS COVERED

The authors describe evidence from randomized controlled trials and systematic reviews on a variety of established medications including anti-inflammatory agents, opioids, anti-convulsants, anti-depressants, N-methyl-D-aspartate receptor antagonists, sodium channel blockers, cannabinoids, and alpha-2-receptor blockers. Furthermore, they provide developing evidence on more novel pharmacotherapeutics including alpha lipoic acid, acetyl-L-carnitine, low dose naltrexone, calcitonin gene-related peptide antagonists, targeted toxin therapy, Nav1.7 inhibitors, neurotensin agonists, purinoceptor antagonists, and sigma-1 receptor antagonists. Furthermore, the authors review the safety and adverse effect profile for these agents.

EXPERT OPINION

In this era of the opioid epidemic, clinicians should first offer non-opioid analgesics and employ a multimodal analgesic strategy. Current guidelines recommend a personalized approach to the chronic pain treatment, in each case accounting for type, location, severity, and chronicity of pain. Clinicians should also carefully consider the risk-to-benefit ratio to the patient based on the drug side effect profile, patient age, and comorbidities.

Effects of opioid rotation to buprenorphine/naloxone on pain, pain thresholds, pain tolerance, and quality of life in patients with chronic pain and opioid use disorder

ABSTRACT

Long-term opioid use in patients with chronic noncancer pain (CNCP) can lead to opioid use disorder (OUD) and has been associated with hyperalgesia and reduced quality of life (QoL). Studies suggest antihyperalgesic properties of buprenorphine, and buprenorphine or naloxone (BuNa) has shown beneficial effects on QoL in patients with OUD without CNCP. This study investigated the added value of BuNa in patients with CNCP with OUD on self-reported pain, pain thresholds, pain tolerance, and QoL. In the current study, 43 outpatients with CNCP and OUD were included for inpatient conversion from full μ-receptor agonist opioids to BuNa. Self-reported pain, pain thresholds, pain tolerance, and QoL were determined at baseline and after 2 months of follow-up, using, respectively, a Visual Analogue Scale (VAS-pain and VAS-QoL), quantitative sensory testing, and EuroQol-5 dimensions. In total, 37 participants completed the protocol, and their data were analyzed. The mean VAS-pain score decreased from 51.3 to 37.2 (27.5%, F = 3.3; P = 0.044), whereas the pressure pain threshold and electric pain threshold or tolerance increased after substitution (F = 7.8; P = 0.005 and F = 44.5; P < 0.001, respectively), as well as QoL (EuroQol-5 dimensions questionnaire: F = 10.4; P = 0.003 and VAS-QoL: F = 4.4; P = 0.043). We found that conversion of full μ-receptor agonists to BuNa, in patients with CNCP with OUD, was accompanied with lower self-reported pain, higher pain thresholds, higher pain tolerance, and improved QoL. Despite several study limitations, these data suggest that BuNa might be of value in patients with CNCP with OUD. Future studies should investigate long-term effects of BuNa in randomized trials.

Buprenorphine Naloxone and Extended Release Injectable Naltrexone for the Treatment of Opioid Use Disorder Among a Veteran Patient Sample: A Retrospective Chart Review

Previous research has demonstrated the effectiveness of both extended-release injectable naltrexone (XR-NTX) and buprenorphine/naloxone (BUP-NX) in the treatment of opioid use disorder (OUD). However, studies using real-world samples with multiple medical and psychiatric comorbidities are lacking. The study's primary aims were to: (1) compare clinical presentations in an inclusive sample of OUD-diagnosed US military veterans receiving XR-NTX and BUP-NX, and (2) investigate differences in 90-day treatment outcomes between these two groups. Methods: The medical records of 79 patients receiving medications to treat OUD in a VA hospital's addiction outpatient treatment program were reviewed retrospectively. The analysis included all veterans who initiated medication treatment during the study period. Differences between medication groups on co-occurring diagnoses, treatment retention, and related outcomes were examined. Results: The two groups were similar in medical and psychiatric comorbidity, although the BUP-NX group were more likely to have a pain diagnosis. No statistically significant differences in retention or toxicology results were found between the two groups over the 90-day study period. The rate of positive urine screens for the BUP-NX group was 19.2% for opiates and 13.5% for other illicit substances, and 3.7% and 11.1% respectively for the XR- NTX group. Conclusion: There was no evidence that 90-days outcomes differed for veterans based on medication received, and there were more similarities than differences in clinical characteristics. Additional research is needed, including larger sample size and prospective randomized control trial to evaluate VA patients' treatment outcomes receiving BUP-NX or XR-NTX for OUD.

Opioid dependence disorder and comorbid chronic pain: comparison of groups based on patient-attributed direction of the causal relationship between the two conditions

Background:

Chronic pain is highly prevalent in treatment-seeking opioid-dependent patients; therefore, this comorbid presentation is an important clinical consideration for both addiction and pain specialists. The objectives of the present study were to examine whether the direction of causal attribution of opioid dependence disorder and chronic pain resulted in two distinct clinical populations, and, if so, to compare treatment received during the 5-year follow-up period.

Methods:

Participants comprised opioid-dependent patients with chronic pain who reported a perceived causal relationship, in either direction, between the development of these two conditions (n = 252). A range of health- and addiction-related instruments were used at study inception. Treatment characteristics were obtained for the follow-up period from national health registers.

Results:

Those reporting that pain caused opioid dependence disorder (n = 174; 69%) were characterised by poorer pain-related health, more illicit cannabinoid use (p = 0.031), more frequent illicit use of opioid analgesics (p = 0.025) and they were in receipt of higher doses of prescribed opioid analgesics. Those reporting that opioid dependence disorder caused pain (n = 78; 31%) were characterised by poorer overall physical health (p = 0.002), more severe psychiatric symptoms and more overall drug use (p = 0.001).

Conclusion:

Two distinct clinical populations were identified, determined by how participants perceive the causal relationship between opioid dependence disorder and chronic pain. These two populations have differing clinical profiles and treatment requirements: those reporting that pain caused opioid dependence disorder were characterised by poorer pain-related health and more illicit use of drugs with analgesic properties; and those reporting that opioid dependence disorder caused pain were characterised by more overall use of substances, multiple substance use and more intravenous substance use and poorer general health. Identifying the causal direction, where such a relationship exists, could help addiction and pain services to develop more effective, individualised treatment strategies.

Benefit-Risk Analysis of Buprenorphine for Pain Management

Health care providers in the United States are facing challenges in selecting appropriate medication for patients with acute and chronic pain in the midst of the current opioid crisis and COVID-19 pandemic. When compared with conventional opioids, the partial µ-opioid receptor agonist buprenorphine has unique pharmacologic properties that may be more desirable for pain management. The formulations of buprenorphine approved by the US Food and Drug Administration for pain management include intravenous injection, transdermal patch, and buccal film. A comparison of efficacy and safety data from studies of buprenorphine and conventional opioids suggests that buprenorphine may be a better-tolerated treatment option for many patients that provides similar or superior analgesia. Our benefit-risk assessment in this narrative review suggests that health care providers should consider that buprenorphine may be an appropriate alternative for pain management over other opioids.