Buprenorphine implant for opioid addiction

In Vitro-In Vivo Correlation of Buprenorphine Transdermal Systems Under Normal and Elevated Skin Temperature

PURPOSE

Application of external heat using a heating pad over buprenorphine transdermal system, Butrans® has been shown to increase systemic levels of buprenorphine in human volunteers. The purpose of this study was to perform in vitro permeation studies at normal as well as elevated temperature conditions to evaluate the correlation of in vitro data with the existing in vivo data.

METHODS

In vitro permeation tests (IVPT) were performed on human skin from four donors. The IVPT study design was harmonized to a previously published clinical study design and skin temperature was maintained at either 32 ± 1 °C or 42 ± 1 °C to mimic normal and elevated skin temperature conditions, respectively.

RESULTS

IVPT studies on human skin were able to demonstrate heat induced enhancement in flux and cumulative amount of drug permeated from Butrans® which was reasonably consistent with the corresponding enhancement observed in vivo. Level A in vitro-in vivo correlation (IVIVC) was established using unit impulse response (UIR) based deconvolution method for both baseline and heat arms of the study. The percent prediction error (%PE) calculated for AUC and C_max values was less than 20%.

CONCLUSIONS

The studies indicated that IVPT studies performed under the same conditions as those of interest in vivo may be useful for comparative evaluation of the effect of external heat on transdermal delivery system (TDS). Further research may be warranted to evaluate factors, beyond cutaneous bioavailability (BA) assessed using an IVPT study, that can influence plasma exposure in vivo for a given drug product.

Three-year Retention Rates With Office-based Treatment of Buprenorphine for Opioid Use Disorder in a Private Family Medicine Practice

OBJECTIVE

Although primary care settings have benefits for implementing office-based opioid treatment (OBOT) programs with buprenorphine, few studies have examined the impact on patient retention beyond 12 months. The objective of this study is to assess long-term outcomes of buprenorphine treatment for opioid use disorder (OUD) integrated into comprehensive primary care treatment at a family medicine practice.

METHODS

A retrospective chart review of patients diagnosed with OUD who received treatment with buprenorphine between December 2006 and January 2018 was conducted at private family medicine practice in semirural Upstate New York. Patients were seen continuously by the same provider. The primary outcome was retention in OBOT at 3 years.

RESULTS

The primary outcome was met by 47.4% of included patients (N = 152). Mean retention in care for all patients was 24.3 months. More than three quarters of patients (77%) had a least one psychiatric comorbidity managed by the practice, most commonly depression (59.9%). Self-reported history of intravenous drug use at baseline was associated with a higher likelihood of patient dropout at year 1 (odds ratio, 2.99; 95% confidence interval, 1.39-6.44; P = 0.004) and year 2 (odds ratio, 2.46; 95% confidence interval, 1.15-5.28; P = 0.019), with no difference observed at year 3.

CONCLUSIONS

Office-based opioid treatment with buprenorphine in a family medicine practice setting resulted in high retention rates, emphasizing the importance of continuity of care and integration of primary care within the OUD treatment model. Further research is needed on barriers to implementation of OBOT among family medicine providers.

Racial and Ethnic Disparities in Buprenorphine and Extended-Release Naltrexone Filled Prescriptions During the COVID-19 Pandemic

Importance

COVID-19 disrupted delivery of buprenorphine and naltrexone treatment for opioid use disorder (OUD), and during the pandemic, members of racial and ethnic minority groups experienced increased COVID-19 and opioid overdose risks compared with White individuals. However, whether filled buprenorphine and naltrexone prescriptions varied across racial and ethnic groups during the COVID-19 pandemic remains unknown.

Objective

To investigate whether disruptions in filled buprenorphine and naltrexone prescriptions differed by race and ethnicity and insurance status or payer type.

Design, Setting, and Participants

This cross-sectional study used retail pharmacy claims from May 2019 to June 2021 from the Symphony Health database, which includes 92% of US retail pharmacy claims, with race and ethnicity data spanning all insurance status and payer categories. Interrupted time series were used to estimate levels and trends of dispensed buprenorphine and naltrexone prescriptions before and after pandemic onset. Included individuals were those who filled buprenorphine and extended-release naltrexone prescriptions. Data were analyzed from July 2021 through March 2022.

Main Outcomes and Measures

Weekly rates of dispensed buprenorphine and extended-release naltrexone prescription fills per 1000 patients and proportion of longer (ie, ≥14 days' supply) buprenorphine prescription fills were calculated. Analyses were stratified by patient race and ethnicity and further by insurance status and payer type for White and Black patients.

Results

A total of 1 556 860 individuals who filled buprenorphine prescriptions (4359 Asian [0.3%], 94 657 Black [6.1%], 55 369 Hispanic [3.6%], and 664 779 White [42.7%]) and 127 506 individuals who filled extended-release naltrexone prescriptions (344 Asian [0.3%], 8186 Black [6.4%], 5343 Hispanic [4.2%], and 53 068 White [41.6%]) from May 6, 2019, to June 5, 2021, were analyzed. Prepandemic increases in buprenorphine fill rate flattened for all groups after COVID-19 onset (30.5 percentage point difference in trend; P < .001) compared with prepandemic trends. Significant level decreases in buprenorphine fills (ranging from 2.5% for Black patients; P = .009 to 4.0% for Hispanic patients; P = .009) at pandemic onset were observed for members of racial and ethnic minority groups but not White patients. At pandemic onset, rate of buprenorphine fills decreased in level for Medicare and cash-paying patients but with greater decreases for Black patients (Medicare: 10.0%; P < .001; cash: 20.0%; P < .001) than White patients (Medicare: 3.5%; P = .004; cash: 15.0%; P < .001). No decreases were found among Medicaid patients. Unlike buprenorphine, extended-release naltrexone had uniform level (from 10.0% for White patients with private insurance; P < .001 to 23.3% for Black patients with Medicare; P < .001) and trend (from 15.5 percentage points for White patients with Medicaid; P = .001 to 52.0 percentage points for Black patients with private insurance; P < .001) decreases across groups.

Conclusions and Relevance

This study found that the COVID-19 pandemic was associated with immediate decreases in filled buprenorphine prescriptions by members of racial and ethnic minority groups but not White individuals. These findings suggest that members of racial and ethnic minority groups had larger losses in buprenorphine access during the pandemic across payer types.

The Association Between Scope of Practice Regulations and Nurse Practitioner Prescribing of Buprenorphine After the 2016 Opioid Bill

This article examines the relationship between federal regulations, state scope-of-practice regulations on nurse practitioners (NPs), and buprenorphine prescribing patterns using pharmacy claims data from Optum's deidentified Clinformatics Data Mart between January 2015 and September 2018. The county-level proportion of patients filling prescriptions written by NPs was low even after the 2016 Comprehensive Addiction and Recovery Act (CARA), 2.7% in states that did not require physician oversight of NPs, and 1.1% in states that did. While analyses in rural counties showed higher rates of buprenorphine prescriptions written by NPs, rates were still considerably low: 3.7% in states with less restrictive regulations and 1.1% in other states. These results indicate that less restrictive scope-of-practice regulations are associated with greater NP prescribing following CARA. The small magnitude of the changes indicates that federal attempts to expand treatment access through CARA have been limited.

Physiologically-Based Pharmacokinetic (PBPK) Modeling of Buprenorphine in Adults, Children and Preterm Neonates

Buprenorphine plays a crucial role in the therapeutic management of pain in adults, adolescents and pediatric subpopulations. However, only few pharmacokinetic studies of buprenorphine in children, particularly neonates, are available as conducting clinical trials in this population is especially challenging. Physiologically-based pharmacokinetic (PBPK) modeling allows the prediction of drug exposure in pediatrics based on age-related physiological differences. The aim of this study was to predict the pharmacokinetics of buprenorphine in pediatrics with PBPK modeling. Moreover, the drug-drug interaction (DDI) potential of buprenorphine with CYP3A4 and P-glycoprotein perpetrator drugs should be elucidated. A PBPK model of buprenorphine and norbuprenorphine in adults has been developed and scaled to children and preterm neonates, accounting for age-related changes. One-hundred-percent of the predicted AUC_last values in adults (geometric mean fold error (GMFE): 1.22), 90% of individual AUC_last predictions in children (GMFE: 1.54) and 75% in preterm neonates (GMFE: 1.57) met the 2-fold acceptance criterion. Moreover, the adult model was used to simulate DDI scenarios with clarithromycin, itraconazole and rifampicin. We demonstrate the applicability of scaling adult PBPK models to pediatrics for the prediction of individual plasma profiles. The novel PBPK models could be helpful to further investigate buprenorphine pharmacokinetics in various populations, particularly pediatric subgroups.

Perioperative Management of a Patient Taking Suboxone® at the Time of Ambulatory Surgery

In 2016, more than 11 million people reported misuse of opioids in the previous year. In an effort to combat opioid use disorder (OUD), the use of agonist/antagonist is becoming increasingly common, with more than 2.2 million patients reporting use of a buprenorphine containing medication such as Suboxone®. Buprenorphine is a unique opioid which acts as a partial μ agonist and ĸ antagonist. These properties make it an effective tool in treating OUD and abuse. However, despite its advantages in treating OUD and abuse, buprenorphine can make it difficult to control acute perioperative pain. We present a case in which the Mayo Clinic Arizona protocol for patients undergoing minimally invasive ambulatory surgery while taking Suboxone® is successfully executed, resulting in adequate postoperative pain control and timely discharge from the postanesthesia recovery unit.

Perceptions and preferences for long-acting injectable and implantable medications in comparison to short-acting medications for opioid use disorders

Aim

Treatment for opioid use disorders has recently evolved to include long-acting injectable and implantable formulations of medications for opioid use disorder (MOUD). Incorporating patient preferences into treatment for substance use disorders is associated with increased motivation and treatment satisfaction. This study sought to assess treatment preferences for long-acting injectable and implantable MOUD as compared to short-acting formulations among individuals with OUD.

Methods

We conducted qualitative, semi-structured telephone interviews with forty adults recruited from across the United States through Craigslist advertisements and flyers posted in treatment programs. Eligible participants scored a two or greater on the heroin or opioid pain reliever sections of the Tobacco, Alcohol, Prescription Medications, and Other Substances (TAPS) Tool, indicative of a past-year OUD. Interviews were transcribed, coded, and thematically analyzed.

Results

Twenty-four participants (60%) currently or previously had been prescribed MOUD. Sixteen participants (40%) expressed general opposition to MOUD, citing concerns that MOUD is purely financial gain for pharmaceutical companies and/or a "band aid" solution replacing one drug with another, rather than a path to abstinence. Some participants expressed personal preference for long-acting injectable (n = 16/40: 40%) and implantable formulations (n = 12/40: 30%) over short-acting formulations. About half of the participants were not willing to use injectables (n = 19/40: 48%) or implantables (n = 22/40: 55%), preferring short-acting formulations. Mixed evaluations of long- and short-acting MOUD focused on considerations of medication-related beliefs (privacy, concern over an embedded foreign body), the medication-related burden (convenience, provision of structure and support, medication administration, potential side effects), and medication-taking practices (potential for non-prescribed use, control over dosage, and duration of treatment).

Conclusions

Though many participants personally prefer short-acting to long-acting MOUD, some were open to including long-acting formulations in the range of options for those with OUD. Participants felt long-acting formulations may reduce medication-related burden and the risk of diversion. Conversely, participants expressed concern about invasive administration and loss of control over their treatment. Results suggest support for expanded access to a variety of formulations of MOUD. The use of shared decision making may also help patients select the formulation best aligned with their experiences, values, and treatment goals.

Policy Pathways to Address Provider Workforce Barriers to Buprenorphine Treatment

At least 2.3 million people in the U.S. have an opioid use disorder, less than 40% of whom receive evidence-based treatment. Buprenorphine used as part of medication-assisted treatment has high potential to address this gap because of its approval for use in non-specialty outpatient settings, effectiveness at promoting abstinence, and cost effectiveness. However, less than 4% of licensed physicians are approved to prescribe buprenorphine for opioid use disorder, and approximately 47% of counties lack a buprenorphine-waivered physician. Existing policies contribute to workforce barriers to buprenorphine provision and access. Providers are reticent to prescribe buprenorphine because of workforce barriers, such as (1) insufficient training and education on opioid use disorder treatment, (2) lack of institutional and clinician peer support, (3) poor care coordination, (4) provider stigma, (5) inadequate reimbursement from private and public insurers, and (6) regulatory hurdles to obtain the waiver needed to prescribe buprenorphine in non-addiction specialty treatment settings. Policy pathways to addressing these provider workforce barriers going forward include providing free and easy-to-access education for providers about opioid use disorders and medication-assisted treatment, eliminating buprenorphine waiver requirements for those licensed to prescribe controlled substances, enforcing insurance parity requirements, requiring coverage of evidence-based medication-assisted treatment as essential health benefits, and providing financial incentives for care coordination across healthcare professional types-including behavioral health counselors and other non-physicians in specialty and non-specialty settings.

SUPPLEMENT INFORMATION

This article is part of a supplement entitled The Behavioral Health Workforce: Planning, Practice, and Preparation, which is sponsored by the Substance Abuse and Mental Health Services Administration and the Health Resources and Services Administration of the U.S. Department of Health and Human Services.

Psychotropic implant can be a new hope in psychiatry

Non-adherence to oral psychotropic medications is common in patients with severe mental illness (SMI). This substantially limits the effectiveness of treatment and results in higher rates of relapse, rehospitalization, suicide, early mortality and disability in SMI. This is a major concern for professionals, caregivers and policy makers. The pharmacological, psychological, psychosocial models and interventions have been there since last few decades to address non-adherence. These have not made major changes in treatment adherence and outcome of SMI. Hence new powerful, long acting and novel psychotropic implant can be developed and could soon revolutionize the treatment in psychiatry.

Probuphine® (buprenorphine implant): a promising candidate in opioid dependence

Opioid dependence leads to physical dependence and addiction which finally results in profound medical, psychological and social dysfunction. One of the useful medications for opioid dependence is buprenorphine, the partial opioid agonist, which is used alone or in combination with naloxone. However, buprenorphine is the victim of its own success due to its illicit use and accidental poisoning in children. Also, buprenorphine typically requires daily self-administration and its effectiveness heavily depends on patient adherence. So, poor treatment adherence results in ineffective treatment manifesting as craving and withdrawal symptoms. Short-term use of buprenorphine in opioid dependence is also often followed by relapse. Buprenorphine when used sublingually often results in inadequate or fluctuating blood concentrations and poorer treatment retention compared with methadone. All of these led to the development of Probuphine®, a polymeric matrix composed of ethylene vinyl acetate and buprenorphine in the form of implants, that are implanted subdermally in office practice and deliver the active drug over 6 months. Buprenorphine release from such implant is fairly consistent, avoiding plasma peaks and troughs, and the implant is also reported to be safe. In this review article, we have highlighted these aspects of treatment of opioid addiction, stressing on the pharmacology of buprenorphine and Probuphine®, and relevant clinical trials addressing the efficacy and safety of Probuphine®. This sustained-release implantable formulation of buprenorphine has the potential to be a suitable alternative to daily or alternate day sublingual buprenorphine which can thereby eliminate the need for daily supervision, minimizing fluctuations in plasma concentrations, and allowing these patients to reduce clinic or pharmacy visits.

The New Kid on the Block--Incorporating Buprenorphine into a Medical Toxicology Practice

Buprenorphine represents a safe and effective therapy for treating opioid dependence, alleviating craving and withdrawal symptoms in opioid-dependent patients. Buprenorphine has a "blocking" effect against the action of other opioids at the mu-receptor, preventing not only opioid-induced euphoria, but CNS and respiratory depressant effects as well. Buprenorphine was approved for the treatment of opioid dependence in 2002 after the passage of Drug Abuse Treatment Act 2000 (DATA 2000) which allowed clinicians to treat opioid-dependent patients with specifically named opioid agonist therapies in an office setting. Buprenorphine programs reduce the prevalence of HIV and hepatitis C and reduce criminal behaviors associated with illicit drug use. Patients stabilized on buprenorphine have increased employment, enhanced engagement with social services, and better overall health and well-being.

A Perspective on Opioid Pharmacotherapy: Where We Are and How We Got Here

Four decades of concerted pharmacotherapy research has netted us three medications approved for the treatment of opioid addiction. The clinical pharmacology, safety, efficacy, and clinical use of these medications are familiar to most clinical researchers and clinicians in addiction medicine. Less common is an understanding of the social and political forces behind the choice of these particular agents for their development and how these forces continue to influence how clinicians interact with patients who have opioid use disorder. This review brings into focus those forces and puts into context how we came to have these particular medications. What we know determines our views of the world we live in, including our patients and ourselves, as well as those to whom we give power to govern us. The issues are raised by the author, who does not provide resolutions; answers to the questions of how to address the issues must come from the reader.

Buprenorphine infrequently found in fatal overdose in New York City

BACKGROUND

Buprenorphine is an opioid agonist medication that is both safe and effective in the treatment of opioid use disorders and the prevention of opioid overdoses. Despite this, media coverage has highlighted public concerns about the potential safety consequences of buprenorphine misuse and diversion. To address the possible contribution of buprenorphine to overdose mortality, we systematically tested post mortem blood specimens from decedents who had died of an unintentional drug overdoses in 2013.

METHODS

We retrospectively tested consecutive drug overdose cases that occurred from June through October 2013. Cases with available blood specimens were tested for buprenorphine and norbuprenorphine using liquid chromatography-tandem mass spectrometry. Toxicology results were linked to death certificates and case files from New York City Vital Statistics and New York City Office of the Chief Medical Examiner.

RESULTS

Of the 98 unintentional drug overdose fatalities tested, only 2 (2.0%) tested positive for buprenorphine metabolites. All 98 unintentional fatalities involved multiple substances.

CONCLUSIONS

Buprenorphine was infrequently found in drug overdose deaths in New York City. Since the safety and efficacy of buprenorphine are well documented, and overdoses resulting from buprenorphine treatment or diversion are very rare, facilitating access to buprenorphine treatment is strongly recommended.

Buprenorphine/naloxone treatment practices in Malaysia: Results of national surveys of physicians and patients

OBJECTIVE

Medication assisted treatment with buprenorphine/naloxone (Bup/Nx), including prescribing and dispensing practices of general practitioners (GPs) in Malaysia and their patients' experiences with this treatment have not been systematically examined. The current study surveyed GPs providing Bup/Nx treatment and patients receiving office-based Bup/Nx treatment in Malaysia.

METHODS

Two cross-sectional surveys of GPs (N=115) providing outpatient Bup/Nx maintenance treatment and of patients (N=253) currently receiving Bup/Nx treatment throughout peninsular Malaysia.

RESULTS

Physicians prescribed Bup/Nx dosages in the range of 2-4mg daily for 70% of patients and conducted urine testing in the past month on approximately 16% of their patients. In the patient survey, 79% reported taking daily Bup/Nx doses of 2mg or less; 82% reported that no urine toxicology testing had been conducted on them in the past month, 36% had an opiate positive urine test at the time of the survey, 43% reported illicit opiate use, 15% reported injection of heroin and 22% reported injection of Bup/Nx in the past month.

CONCLUSION

Low daily Bup/Nx doses, lack of behavioral monitoring or counseling, and high rates of continued drug use, including injection of drugs and medications during Bup/Nx treatment in Malaysia, indicate continuing problems with implementation and less than optimal treatment effectiveness. High cost of Bup/Nx in Malaysia may deter patients from seeking treatment and contribute to taking low Bup/Nx dosages. Improved training of physicians and establishing standards for Bup/Nx dosing, routine toxicology testing, and counseling may be needed to improve care and treatment response.

Buprenorphine implant for opioid addiction

SUMMARY The buprenorphine implant (Probuphine™, Titan Pharmaceuticals, CA, USA) is a recently developed long-acting formulation of buprenorphine, which is a partial opioid agonist that is widely used in the marketed, sublingual, daily-dose form for managing opioid addiction. The new formulation uses a novel delivery system consisting of subcutaneously implanted solid matrix 'rods' made from a mixture of ethylene vinyl acetate and buprenorphine. The buprenorphine implant was developed to ensure medication compliance, eliminate misuse and abuse from diversion of sublingual buprenorphine, and increase therapeutic benefit of the medication. The implant is not a 'new' drug, but an innovative means of delivering a medication proven effective for treating opioid addiction. The implant has not yet been approved by the US FDA. The information in this review has been gleaned from research reports, documentation in the literature, and from the author's experience treating opioid-dependent patients, and involvement in clinical research examining sublingual buprenorphine and the buprenorphine implant.