Impact of Fentanyl Use on Buprenorphine Treatment Retention and Opioid Abstinence

Induction to Methadone 80 mg in the First Week of Treatment of Patients Who Use Fentanyl: A Case Series From an Outpatient Opioid Treatment Program

OBJECTIVES

Current guidelines for methadone titration may unnecessarily delay reaching effective doses for patients using fentanyl, resulting in an increased risk of ongoing fentanyl use, dissatisfaction with treatment, and early dropout. Development and evaluation of rapid methadone induction protocols may improve treatment for patients using fentanyl.

METHODS

Retrospective chart review was conducted for patients admitted in 2022 to a single licensed opioid treatment program (OTP) where a rapid induction protocol provides methadone 40 mg on day 1, 60 mg on day 2, and 80 mg on day 3 to patients using fentanyl <65 years old without significant medical comorbidities. The primary feasibility outcome was completion of the protocol, defined by receipt of methadone dose 80 mg or more on treatment day 7. The primary safety outcomes were oversedation, nonfatal overdose, and death. A secondary outcome was retention in treatment at 30 days.

RESULTS

Rapid induction was ordered for 93 patients and completed by 65 (70%). Average dose on day 7 for patients who completed was 89 mg (SD 9.5 mg) versus 49 mg (SD 14.0 mg) for those who did not. No episodes of oversedation, nonfatal overdose, or death were observed. At 30 days, 85% of the patients who had the rapid protocol ordered (79/93) were retained, with 88% (57/65) who completed the protocol retained versus 79% (22/28) who did not complete (OR 1.9, 95% CI 0.6-6.2).

CONCLUSIONS

Rapid induction to methadone 80 mg by day 7 was feasible for outpatients using fentanyl in this study at a single OTP. No significant safety events were identified.

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.

Extended-Release Injection vs Sublingual Buprenorphine for Opioid Use Disorder With Fentanyl Use: A Post Hoc Analysis of a Randomized Clinical Trial

Importance

Fentanyl has exacerbated the opioid use disorder (OUD) and opioid overdose epidemic. Data on the effectiveness of medications for OUD among patients using fentanyl are limited.

Objective

To assess the effectiveness of sublingual or extended-release injection formulations of buprenorphine for the treatment of OUD among patients with and without fentanyl use.

Design, Setting, and Participants

Post hoc analysis of a 24-week, randomized, double-blind clinical trial conducted at 35 outpatient sites in the US from December 2015 to November 2016 of sublingual buprenorphine-naloxone vs extended-release subcutaneous injection buprenorphine (CAM2038) for patients with OUD subgrouped by presence vs absence of fentanyl or norfentanyl in urine at baseline. Study visits with urine testing occurred weekly for 12 weeks, then 6 times between weeks 13 and 24. Data were analyzed on an intention-to-treat basis from March 2022 to August 2023.

Intervention

Weekly and monthly subcutaneous buprenorphine vs daily sublingual buprenorphine-naloxone.

Main Outcomes and Measures

Retention in treatment, percentage of urine samples negative for any opioids (missing values imputed as positive), percentage of urine samples negative for fentanyl or norfentanyl (missing values not imputed), and scores on opiate withdrawal scales and visual analog craving scales.

Results

Of 428 participants, 123 (subcutaneous buprenorphine, n = 64; sublingual buprenorphine-naloxone, n = 59; mean [SD] age, 39.1 [10.8] years; 75 men [61.0%]) had evidence of baseline fentanyl use and 305 (subcutaneous buprenorphine, n = 149; buprenorphine-naloxone, n = 156; mean [SD] age, 38.1 [11.1] years; 188 men [61.6%]) did not have evidence of baseline fentanyl use. Study completion was similar between the fentanyl-positive (60.2% [74 of 123]) and fentanyl-negative (56.7% [173 of 305]) subgroups. The mean percentage of urine samples negative for any opioid were 28.5% among those receiving subcutaneous buprenorphine and 18.8% among those receiving buprenorphine-naloxone in the fentanyl-positive subgroup (difference, 9.6%; 95% CI, -3.0% to 22.3%) and 36.7% among those receiving subcutaneous buprenorphine and 30.6% among those receiving buprenorphine-naloxone in the fentanyl-negative subgroup (difference, 6.1%; 95% CI, -1.9% to 14.1%), with significant main associations of baseline fentanyl status and treatment group. In the fentanyl-positive subgroup, the mean percentage of urine samples negative for fentanyl during the study was 74.6% among those receiving subcutaneous buprenorphine vs 61.9% among those receiving sublingual buprenorphine-naloxone (difference, 12.7%; 95% CI, 9.6%-15.9%). Opioid withdrawal and craving scores decreased rapidly after treatment initiation across all groups.

Conclusions and Relevance

In this post hoc analysis of a randomized clinical trial of sublingual vs extended-release injection buprenorphine for OUD, buprenorphine appeared to be effective among patients with baseline fentanyl use. Patients with fentanyl use had fewer opioid-negative urine samples during the trial compared with the fentanyl-negative subgroup. These findings suggest that the subcutaneous buprenorphine formulation may be more effective at reducing fentanyl use.

Trial Registration

ClinicalTrials.gov Identifier: NCT02651584.

Longitudinal patterns of use of stimulants and opioids in the AIDS linked to the IntraVenous experience cohort, 2005-2019

BACKGROUND

Overdoses involving opioids and stimulants are on the rise, yet few studies have examined longitudinal trends in use of both substances. We sought to describe use and co-use of opioids and stimulants, 2005-2019, in the AIDS Linked to the Intravenous Experience (ALIVE) cohort - a community-based cohort of people with a history of injection drug use living in or near Baltimore, MD.

METHODS

We included 2083 ALIVE participants, who had at least two visits during the study period. Our outcome was based on self-reported use of opioids and stimulants in the prior 6 months. We estimated prevalence of 4 categories of use (neither stimulants nor opioids, only stimulants, only opioids, stimulants and opioids), using a non-parametric multi-state model, accounting for the competing event of death and weighting for informative loss to follow-up. All analyses were stratified by enrollment cohort, with the main analysis including participants who enrolled prior to 2015 and a sub-analysis including participants who enrolled 2015-2018.

RESULTS

In the main analysis, prevalence of using stimulants and opioids decreased from 38 % in 2005 to 12 % 2013 but stabilized from 2014 onwards (13-19 %). The prevalence of using only stimulants (7-11 %) and only opioids (5-10 %) was stable across time. Participants who reported using both were more likely to report homelessness, depression, and other substance use (e.g., marijuana and heavy alcohol use) than participants in the other use categories. On average, 65 % of visits with use of both were followed by a subsequent visit with use of both; of participants transitioning out of using both, 13% transitioned to using neither.

CONCLUSIONS

While use of stimulants and opioids declined in the cohort through 2013, a meaningful proportion of participants persistently used both. More research is needed to understand and develop strategies to mitigate harms associated with persistent use of both stimulants and opioids.

Overview of best practices for buprenorphine initiation in the emergency department

In recent decades, opioid overdoses have increased dramatically in the United States and peer countries. Given this, emergency medicine physicians have become adept in reversing and managing complications of acute overdose. However, many remain unfamiliar with initiating medication for opioid use disorder such as buprenorphine, a high-affinity partial opioid agonist. Emergency department-based buprenorphine initiation is supported by a significant body of literature demonstrating a marked reduction in mortality in addition to increased engagement in care. Buprenorphine initiation is also safe, given both the pharmacologic properties of buprenorphine that reduce the risk of diversion or recreational use, and previously published literature demonstrating low rates of respiratory depression, sedation, and precipitated withdrawal. Further, barriers to emergency department-based initiation have been reduced in recent years, with publicly available dosing and up-titration schedules, numerous publications overviewing best practices for managing precipitated withdrawal, and removal of USA policies previously restricting patient access and provider prescribing, with the removal of the X-waiver via the Medication Access and Training Expansion Act. Despite reductions in barriers, buprenorphine initiation in the emergency room remains underutilized. Poor uptake has been attributed to numerous individual and systemic barriers, including inadequate education, provider stigma, and insufficient access to outpatient follow-up care. The following practice innovation aims to summarize previously published evidence-based best practices and provide an accessible, user-friendly initiation guide to increase emergency physician comfortability with buprenorphine initiation going forward.

Novel Therapeutic and Program-Based Approaches to Opioid Use Disorders

Opioid use disorder continues to drive overdose deaths in many countries, including the United States. Illicit fentanyl and its analogues have emerged as key contributors to the complications and mortality associated with opioid use disorder. Medications for opioid use disorder treatment, such as methadone and buprenorphine, are safe and substantially reduce opioid use, infectious complications, and mortality risk, but remain underutilized. Polysubstance use and emerging substances such as xylazine and designer benzodiazepines create additional treatment challenges. Recent clinical and policy innovations in treatment delivery, including telemedicine, bridge clinics, and expanded models for accessing methadone have the potential to increase access to life-saving care for people living with opioid use disorder.

Buprenorphine deregulation as an opioid crisis policy response - A comparative analysis between France and the United States

BACKGROUND

In passing the Maintstreaming Addiction Treatment Act, the United States has abolished its federal X waiver, considered a major barrier to the wider buprenorphine prescribing needed to respond to opioid-related harms. Advocates for this policy have drawn on the French response of deregulating buprenorphine prescribing to address increasing overdose mortality around the turn of the millennium. So far, such policy advocacy has incompletely accounted for contextual and health system differences between the two countries.

METHODS

Using the health system dynamics framework, this analysis compares France from 1995 to 2003 (the relevant period of buprenorphine reform) to the US from 2018 until today (the comparison period to explore potential impacts of reform). We used it to guide examination of a) contextual issues relating to opioid use epidemiology and b) health system factors including prescriber supply, sector organization, and insurance coverage for primary care to draw relevant policy learning for the contemporary US.

RESULTS

We identified that the US had a 22.5-fold higher mortality rate and a 2.3-fold higher opioid use disorder (OUD) rate compared to France, despite having rates of prescribed buprenorphine per-capita higher than, and per-person with OUD comparable to, than that of France. These wide gulfs between the scales and nature of the problems between France and the US suggest that relaxing restrictions on buprenorphine prescribing through abolishing the X waiver will be insufficient for achieving hoped-for reductions in overdose mortality.

CONCLUSION

Health system strengthening with a focus on improvements in primary care prescriber supply, coverage, and coordination are likely higher yield policy complements to relaxing buprenorphine regulation. Such an approach would better prepare the US to adapt to ongoing dynamics and uncertainties in the opioid crisis and to optimize the already relatively high levels of buprenorphine prescribing.

Evidence on Buprenorphine Dose Limits: A Review

OBJECTIVES

As overdose deaths from fentanyl continue to increase, optimizing use of medications for opioid use disorder has become increasingly important. Buprenorphine is a highly effective medication for reducing the risk of overdose death, but only if a patient remains in treatment. Shared decision making between prescribers and patients is important to establish a dose that meets each patient's treatment needs. However, patients frequently face a dose limit of 16 or 24 mg/d based on dosing guidelines on the Food and Drug Administration's package label.

METHODS

This review discusses patient-centered goals and clinical criteria for determining dose adequacy, reviews the history of buprenorphine dose regulation in the United States, examines pharmacological and clinical research results with buprenorphine doses up to 32 mg/d, and evaluates whether diversion concerns justify maintaining a low buprenorphine dose limit.

RESULTS

Pharmacological and clinical research results consistently demonstrate buprenorphine's dose-dependent benefits up to at least 32 mg/d, including reductions in withdrawal symptoms, craving, opioid reward, and illicit use while improving retention in care. Diverted buprenorphine is most often used to treat withdrawal symptoms and reduce illicit opioid use when legal access to it is limited.

CONCLUSIONS

In light of established research and profound harms from fentanyl, the Food and Drug Administration's current recommendations on target dose and dose limit are outdated and causing harm. An update to the buprenorphine package label with recommended dosing up to 32 mg/d and elimination of the 16 mg/d target dose would improve treatment effectiveness and save lives.

Differential effect of cannabis use on opioid agonist treatment outcomes: Exploratory analyses from the OPTIMA study

INTRODUCTION

Conflictual evidence exists regarding the effects of cannabis use on the outcomes of opioid agonist therapy (OAT). In this exploratory analysis, we examined the effect of recent cannabis use on opioid use, craving, and withdrawal symptoms, in individuals participating in a trial comparing flexible buprenorphine/naloxone (BUP/NX) take-home dosing model to witnessed ingestion of methadone.

METHODS

We analyzed data from a multi-centric, pragmatic, 24-week, open label, randomized controlled trial in individuals with prescription-type opioid use disorder (n = 272), randomly assigned to BUP/NX (n = 138) or methadone (n = 134). The study measured last week cannabis and opioid use via timeline-follow back, recorded at baseline and every two weeks during the study. Craving symptoms were measured using the Brief Substance Craving Scale at baseline, and weeks 2, 6, 10, 14, 18 and 22. The study measured opioid withdrawal symptoms via Clinical Opiate Withdrawal Scale at treatment initiation and weeks 2, 4, and 6.

RESULTS

The mean maximum dose taken during the study was 17.3 mg/day (range = 0.5-32 mg/day) for BUP/NX group and 67.7 mg/day (range = 10-170 mg/day) in the methadone group. Repeated measures generalized linear mixed models demonstrated that cannabis use in the last week (mean of 2.3 days) was not significantly associated with last week opioid use (aβ ± standard error (SE) = -0.06 ± 0.04; p = 0.15), craving (aβ ± SE = -0.05 ± 0.08, p = 0.49), or withdrawal symptoms (aβ ± SE = 0.09 ± 0.1, p = 0.36). Bayes factor (BF) for each of the tested models supported the null hypothesis (BF < 0.3).

CONCLUSIONS

The current study did not demonstrate a statistically significant effect of cannabis use on outcomes of interest in the context of a pragmatic randomized-controlled trial. These findings replicated previous results reporting no effect of cannabis use on opioid-related outcomes.

Low barrier medication for opioid use disorder at a federally qualified health center: a retrospective cohort study

Background

Medication for opioid use disorder (MOUD) reduces mortality, but few patients access MOUD. At a Federally Qualified Health Center (FQHC), we implemented a low barrier model of MOUD, including same-day MOUD initiation and a harm reduction philosophy.

Objective

To investigate whether low barrier MOUD improved retention in care compared to traditional treatment.

Design and participants

Retrospective cohort study of patients with at least one visit seeking MOUD at the FQHC during a historical control period (3/1/2018—3/31/2019) and a low barrier intervention period (11/1/2019—7/31/2020).

Main measures

Primary outcomes were any MOUD prescription within 6 months of the index visit and 3- and 6-month retention in treatment without care gap, with care gap defined as 60 consecutive days without a visit or prescription. Secondary outcomes were all-cause hospitalization and emergency department visit within 6 months of the index visit.

Key results

Baseline characteristics were similar between the intervention (n = 113) and control (n = 90) groups, except the intervention group had higher rates of uninsured, public insurance and diabetes. Any MOUD prescription within 6 months of index visit was higher in the intervention group (97.3% vs 70%), with higher adjusted odds of MOUD prescription (OR = 4.01, 95% CI 2.08–7.71). Retention in care was similar between groups at 3 months (61.9% vs 60%, aOR = 1.06, 95% CI 0.78–1.44). At 6 months, a higher proportion of the intervention group was retained in care, but the difference was not statistically significant (53.1% vs 45.6%, aOR 1.27, 95% CI 0.93–1.73). There was no significant difference in adjusted odds of 6-month hospitalization or ED visit between groups.

Conclusions

Low barrier MOUD engaged a higher risk population and did not result in any statistically significant difference in retention in care compared with a historical control. Future research should determine what interventions improve retention of patients engaged through low barrier care. Primary care clinics can implement low barrier treatment to make MOUD accessible to a broader population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13722-022-00342-1.

Impact of fentanyl use on initiation and discontinuation of methadone and buprenorphine/naloxone among people with prescription-type opioid use disorder: secondary analysis of a Canadian treatment trial

BACKGROUND AND AIMS

Fentanyl is primarily responsible for the current phase of the overdose epidemic in North America. Despite the benefits of treatment with medications for opioid use disorder (MOUD), there are limited data on the association between fentanyl, MOUD type and treatment engagement. The objectives of this analysis were to measure the impact of baseline fentanyl exposure on initiation and discontinuation of MOUD among individuals with prescription-type opioid use disorder (POUD).

DESIGN, SETTING AND PARTICIPANTS

Secondary analysis of a Canadian multi-site randomized pragmatic trial conducted between 2017 and 2020. Of the 269 randomized participants, 65.4% were male, 67.3% self-identified as white and 55.4% had a positive fentanyl urine drug test (UDT) at baseline. Fentanyl-exposed participants were more likely to be younger, to self-identify as non-white, to be unemployed or homeless and to be currently using stimulants than non-fentanyl-exposed participants.

INTERVENTIONS

Flexible take-home dosing buprenorphine/naloxone or supervised methadone models of care for 24 weeks.

MEASUREMENTS

Outcomes were (1) MOUD initiation and (2) time to (a) assigned and (b) overall MOUD discontinuation. Independent variables were baseline fentanyl UDT (predictor) and assigned MOUD (effect modifier).

FINDINGS

Overall, 209 participants (77.7%) initiated MOUD. In unadjusted analyses, fentanyl exposure was associated with reduced likelihood of treatment initiation [odds ratio (OR) = 0.18, 95% confidence interval (CI) = 0.08-0.36] and shorter median times in assigned [20 versus 168 days, hazard ratio (HR) = 3.61, 95% CI = 2.52-5.17] and any MOUD (27 versus 168 days, HR = 3.32, 95% CI = 2.30-4.80). The negative effects were no longer statistically significant in adjusted models, and no interaction between fentanyl and MOUD was observed for any of the outcomes (all P > 0.05).

CONCLUSIONS

Both buprenorphine/naloxone and methadone may be appropriate treatment options for people with prescription-type opioid use disorder regardless of fentanyl exposure. Other characteristics of fentanyl-exposed individuals appear to be driving the association with poorer treatment outcomes.

"It's probably going to save my life;" attitudes towards treatment among people incarcerated in the era of fentanyl

INTRODUCTION

In recent years, there has been a dramatic increase in overdose deaths involving illicitly manufactured fentanyl. The risk of death due to fentanyl exposure is far higher for people without adequate tolerance, such as those being released from incarceration. However, little is known about knowledge and perceptions of fentanyl among people who are incarcerated.

METHODS

We conducted 40 semi-structured qualitative interviews with people who were incarcerated at the Rhode Island Department of Corrections (RIDOC). We explored the impressions of, preferences for and experiences with fentanyl among these people. Analysis employed a general, inductive approach using NVivo 12.

RESULTS

We found that a majority of the participants were familiar with fentanyl, sought to avoid it and utilized harm reduction techniques when using drugs and taking treatment with medication for opioid use disorder (MOUD) to reduce their risk of overdose.

DISCUSSION

Our findings suggest that broad access to MOUD, especially for incarcerated people, is increasingly necessary in the era of fentanyl, both to aid people seeking recovery due to the increased overdose risk of drug use and to reduce overdose morbidity for people who use drugs.

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.

Buprenorphine/naloxone associated with a reduced odds of fentanyl exposure among a cohort of people who use drugs in Vancouver, Canada

BACKGROUND

Little is known about the relationship between opioid agonist therapy (OAT) and fentanyl use, specifically. This study aimed to estimate the association between current use of different forms of OAT, including methadone, buprenorphine/naloxone (BUP/NX), slow release oral morphine (SROM), or injectable opioid agonist treatment (iOAT), and the likelihood of a fentanyl-positive urine drug test (UDT) as compared to no OAT.

METHODS

Data were obtained from three community-recruited prospective cohort studies of people who use drugs in Vancouver, Canada from December 2016 through November 2018. Using multivariable Generalized Estimating Equations (GEE), we examined the association between current use of each form of OAT, as compared to no OAT, and fentanyl-positive UDT among participants who use opioids.

RESULTS

The 915 participants contributed 2112 UDTs over a median of two follow-up visits. The majority of UDTs (74.9 %) were positive for fentanyl. After adjustment for a priori defined confounding factors, compared to no OAT, current use of BUP/NX was associated with lower odds of fentanyl-positive UDT (odds ratio [OR] = 0.36, 95 % confidence interval [CI]: 0.22-0.58) while current use of methadone (OR = 0.84, 95 % CI: 0.65-1.07), iOAT (OR = 1.30, 95 % CI: 0.75-2.28), and SROM (OR = 1.34, 95 % CI: 0.74-2.43) were not.

CONCLUSIONS

In this cohort of people who use opioids in Vancouver, only use of BUP/NX was associated with lower odds of fentanyl-positive UDT. Our findings highlight high rates of ongoing fentanyl use despite the use of OAT and support the expansion of BUP/NX for the treatment of people who use fentanyl.

Cannabis use is associated with reduced risk of exposure to fentanyl among people on opioid agonist therapy during a community-wide overdose crisis

BACKGROUND

The ongoing opioid overdose crisis is driven largely by exposure to illicitly-manufactured fentanyl. Preliminary observational and experimental research suggests that cannabis could potentially play a role in reducing use of prescription opioids among individuals with chronic pain. However, there is limited data on the effects of cannabis on illicit opioid consumption, particularly fentanyl, especially among individuals on opioid agonist therapy (OAT). We sought to assess the longitudinal association between cannabis use and exposure to fentanyl among people on OAT.

METHODS

Data were drawn from two community-recruited prospective cohorts of people who use drugs in Vancouver, Canada. We used generalized linear mixed-effects modeling, adjusted by relevant confounders, to investigate the relationship between cannabis use and recent fentanyl exposure (both assessed by urine drug testing) among participants on OAT between 2016 and 2018.

RESULTS

Among the 819 participants on OAT who contributed 1989 observations over the study period, fentanyl exposure was common. At the baseline interview, fentanyl was detected in a majority of participants (431, 53 %), with lower prevalence among individuals with urine drug tests positive for tetrahydrocannabinol (47 vs. 56 %, p = 0.028). Over all study interviews, cannabis use was independently associated with reduced likelihood of being recently exposed to fentanyl (Adjusted Prevalence Ratio = 0.91, 95 % Confidence Interval: 0.83 - 0.99).

CONCLUSIONS

Participants on OAT using cannabis had significantly lower risk of being exposed to fentanyl. Our findings reinforce the need for experimental trials to investigate the potential benefits and risks of controlled cannabinoid administration for people on OAT.

Therapeutic and Prophylactic Vaccines to Counteract Fentanyl Use Disorders and Toxicity

The incidence of fatal overdoses has increased worldwide due to the widespread access to illicit fentanyl and its potent analogues. Vaccines offer a promising strategy to reduce the prevalence of opioid use disorders (OUDs) and to prevent toxicity from accidental and deliberate exposure to fentanyl and its derivatives. This study describes the development and characterization of vaccine formulations consisting of novel fentanyl-based haptens conjugated to carrier proteins. Vaccine efficacy was tested against opioid-induced behavior and toxicity in mice and rats challenged with fentanyl and its analogues. Prophylactic vaccination reduced fentanyl- and sufentanil-induced antinociception, respiratory depression, and bradycardia in mice and rats. Therapeutic vaccination also reduced fentanyl intravenous self-administration in rats. Because of their selectivity, vaccines did not interfere with the pharmacological effects of commonly used anesthetics nor with methadone, naloxone, oxycodone, or heroin. These preclinical data support the translation of vaccines as a viable strategy to counteract fentanyl use disorders and toxicity.

Protracted renal clearance of fentanyl in persons with opioid use disorder

INTRODUCTION

The illicit opioid supply in the U.S. is increasingly adulterated with fentanyl. As such, persons with opioid use disorder (OUD) may be regularly exposed to fentanyl, however, the pharmacokinetics of repeated fentanyl exposure are not well understood. The current study aimed to quantify renal clearance of fentanyl in OUD patients presenting to residential treatment.

METHODS

Participants (N = 12) who presented to a 28-day residential treatment program were enrolled if they tested positive for fentanyl at intake. Urine samples were collected every 2-3 days and were quantitatively tested for fentanyl, norfentanyl, and creatinine via liquid chromatography mass spectrometry (LC-MS). Fentanyl clearance was defined as the time since last illicit opioid use and the median time between last positive and first negative fentanyl urine screen.

RESULTS

Participants had a mean and standard deviation (SD) age of 28.9 (11.0), were 67 % male, and 83 % white. The mean (SD) time for fentanyl and norfentanyl clearance was 7.3 (4.9) and 13.3 (6.9) days, respectively. One participant continued to test positive for fentanyl for 19 days and norfentanyl for 26 days following their last use, and left treatment without testing negative for norfentanyl.

CONCLUSION

Fentanyl clearance in persons with OUD is considerably longer than the typical 2-4 day clearance of other short-acting opioids. The findings of this study might explain recent reports of difficulty in buprenorphine inductions for persons who use fentanyl, and point to a need to better understand the pharmacokinetics of fentanyl in the context of opioid withdrawal in persons who regularly use fentanyl.

One year of methadone maintenance treatment in a fentanyl endemic area: Safety, repeated exposure, retention, and remission

INTRODUCTION

Fentanyl is a potent synthetic opioid that has contributed to increasing overdose deaths in the United States in recent years. Concern over safety and efficacy of agonist treatment for fentanyl use may limit access to treatment. This study sought to address these potential concerns in a naturalistic setting.

OBJECTIVES

Measure 12-month treatment outcomes for methadone maintenance treatment (MMT) in a fentanyl endemic area.

OUTCOMES

Primary: 1) Treatment retention; 2) sustained remission (defined as 3 consecutive negative screens); 3) return to use; 4) methadone dosage required; and 5) number of days to achieve remission. Secondary: Mortality.

METHODS

A naturalistic follow-up study and retrospective review of consecutive patients newly admitted to a single methadone maintenance treatment program in Rhode Island.

RESULTS

We observed 154 unique intake events (representing 151 patients). Eighty percent (n = 121) tested positive for fentanyl at intake. Seventy-five percent of patients achieved remission within the 12-month study period. One-year retention was 53% for fentanyl-exposed individuals and 47% for those not exposed. The majority (99%) of patients who remained in treatment at 12 months achieved remission. We saw prolonged, sustained remission in 44% of patients exposed to fentanyl at intake and 47% of those who were not. Dose and time to remission were similar. Unfortunately, 4 patients died after leaving MMT prematurely.

CONCLUSIONS

This study suggests MMT is safe despite repeated exposure to fentanyl while taking methadone. Remission is achievable, and MMT is protective against death among fentanyl-exposed patients while in treatment.

The rising crisis of illicit fentanyl use, overdose, and potential therapeutic strategies

Fentanyl is a powerful opioid anesthetic and analgesic, the use of which has caused an increasing public health threat in the United States and elsewhere. Fentanyl was initially approved and used for the treatment of moderate to severe pain, especially cancer pain. However, recent years have seen a growing concern that fentanyl and its analogs are widely synthesized in laboratories and adulterated with illicit supplies of heroin, cocaine, methamphetamine, and counterfeit pills, contributing to the exponential growth in the number of drug-related overdose deaths. This review summarizes the recent epidemic and evolution of illicit fentanyl use, its pharmacological mechanisms and side effects, and the potential clinical management and prevention of fentanyl-related overdoses. Because social, economic, and health problems that are related to the use of fentanyl and its analogs are growing, there is an urgent need to implement large-scale safe and effective harm reduction strategies to prevent fentanyl-related overdoses.

Fentanyl exposure and preferences among individuals starting treatment for opioid use disorder

BACKGROUND

Fentanyl has become widespread in the illicit opioid supply, and is a major driver of overdose mortality.

METHODS

This study used a medical records review at a community opioid use disorder treatment program to examine patient-level correlates of fentanyl exposure as measured by urine testing at admission (N= 1,174). Additionally, an anonymous survey was conducted with 114 patients about their experiences and preferences regarding fentanyl.

RESULTS

Overall, 39% of patients entering treatment tested positive for fentanyl. Prevalence of fentanyl exposure differed based on other drug test results (fentanyl-positive = 81.1% vs. 15.4% among participants positive vs. negative for heroin/opioids, p < .001; 59.0% vs. 38.3% among participants positive vs. negative for methadone, p = .001; 53.8% vs. 24.9% among participants positive vs. negative for cocaine, p < .001), prior addiction treatment (40.6% vs. 32.0% among participants with vs. without prior treatment, p < .05), and mental health (36.7% vs. 43.1% among participants with vs. without co-occurring psychiatric diagnosis, p < .05). Most participants reported knowingly using fentanyl (56.1%) and knowing people who prefer fentanyl as a drug of choice (65.8%). Preference for fentanyl (alone or mixed with heroin) was expressed by 44.7% of participants. Participants thought fentanyl withdrawal had faster onset (53.5%), greater severity (74.8%), and longer duration (62.0%) than heroin withdrawal.

CONCLUSIONS

Recent opioid and cocaine use were strongly associated with fentanyl exposure in this sample. Although fentanyl exposure is often unintentional, there may be a subgroup of individuals who come to prefer fentanyl. Future research should examine the relationship between fentanyl use, patient preferences for fentanyl, and treatment outcomes.