Modeling of overdose and naloxone distribution in the setting of fentanyl compared to heroin

Estimating the total utilization of take home naloxone during an unregulated drug toxicity crisis: A Bayesian modeling approach

BACKGROUND

British Columbia (BC) Canada has a large take-home naloxone (THN) program, implemented as part of the provincial response to the ongoing toxic unregulated drug supply emergency. Ascertaining the rate of use of THN kits is vital to understanding the full impact of the program. However, this is a challenging problem due to under-reporting of kit distribution. This study aims to estimate the total number of THN kits used based on the number of THN kits shipped, the number of THN kits reported as distributed, and the number of THN kits reported as used.

METHODS

We used BC THN shipment and distribution records (February 2015 to August 2023) to inform a simple Bayesian model of naloxone kit distribution and use. A logistic regression term by health region and distribution site type was incorporated to account for variable under-reporting, and a convolution term was incorporated to account for kit distribution.

RESULTS

We find the number of THN kits reported as used, and the number of total THN kits distributed, are largely under-reported. An estimated 1,500 (95 % CrI: 1,430 - 1,590) THN kits per 10,000 BC population were used, of which 288 per 10,000 had been reported as used. Of all the THN kits shipped, the model estimated that 43 % (95 % CrI: 41-45 %) of kits were used. We also found variation in both distribution and use by distribution site type, with kits distributed from overdose prevention sites having the highest rate of use (56 %; 95 % CrI: 53-59 %).

CONCLUSION

Across all sites, kit use is approximately five times higher than has been reported. Our framework can also be applied to other localities where THN programs operate, in order to better estimate the true reach and impact of take home naloxone distribution.

Ventilatory Effects of Fentanyl, Heroin, and d-Methamphetamine, Alone and in Mixtures in Male Rats Breathing Normal Air

The number of drug overdoses and deaths has increased significantly over the past decade and co-use of opioids and stimulants is associated with greater likelihood of overdose and decreased likelihood of accessing treatment, compared with use of opioids alone. Potential adverse effects of opioid/stimulant mixtures, particularly methamphetamine, are not well characterized. Two structurally different drugs with agonist properties at µ-opioid receptors (MOR), fentanyl and heroin, and d-methamphetamine, alone and in mixtures, were assessed for their effects on ventilation in rats breathing normal air. Whole-body phethysmography chambers were equipped with a tower and swivel allowing infusions to indwelling intravenous catheters. After a 45-minute habituation period, saline, fentanyl, heroin, or d-methamphetamine, alone and in mixtures, was administered. Five minutes later, the opioid receptor antagonist naloxone or vehicle was injected. Fentanyl (0.0032-0.1 mg/kg) and heroin (0.32-3.2 mg/kg) decreased ventilation [frequency (f) and tidal volume (VT)] in a dose-related manner whereas d-methamphetamine (0.1-3.2 mg/kg) increased f to >400% of control and decreased VT to <60% of control, overall increasing minute volume (product of f and VT) to >240% of control. When combined, d-methamphetamine (0.1-3.2 mg/kg) attenuated the ventilatory depressant effects of fentanyl (0.1 mg/kg) and heroin (3.2 mg/kg). d-Methamphetamine did not alter the potency of naloxone to reverse the ventilatory depressant effects of fentanyl or heroin. These studies demonstrate that d-methamphetamine can attenuate the ventilatory depressant effects of moderate doses of opioid receptor agonists while not altering the potency of naloxone to reverse opioid hypoventilation. SIGNIFICANCE STATEMENT: Co-use of opioids and stimulants is associated with greater likelihood of overdose and decreased likelihood of accessing treatment, compared with use of opioids alone. Potential adverse effects of opioid/stimulant mixtures are not well characterized. This study reports that 1) d-methamphetamine attenuates the ventilatory depressant effects of moderate doses of two structurally different opioid receptor agonists, fentanyl and heroin, and 2) d-methamphetamine does not alter potency or effectiveness of naloxone to reverse the ventilatory depressant effects of these opioid receptor agonists.

Endogenous opiates and behavior: 2022

This paper is the forty-fifth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2022 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

“There’s No Heroin Around Anymore. It’s All Fentanyl.” Adaptation of an Opioid Overdose Prevention Counseling Approach to Address Fentanyl Overdose: Formative Study

Background

Drug overdose mortality continues to increase, now driven by fentanyl. Prevention tools such as naloxone and medications to treat opioid use disorder are not sufficient to control overdose rates; additional strategies are urgently needed.

Objective

We sought to adapt a behavioral intervention to prevent opioid overdose (repeated-dose behavioral intervention to reduce opioid overdose [REBOOT]) that had been successfully piloted in San Francisco, California, United States, to the setting of Boston, Massachusetts, United States, and the era of fentanyl for a full efficacy trial.

Methods

We used the assessment, decision, adaptation, production, topical experts, integration, training, and testing (ADAPT-ITT) framework for intervention adaptation. We first identified opioid overdose survivors who were actively using opioids as the population of interest and REBOOT as the intervention to be adapted. We then performed theater testing and elicited feedback with 2 focus groups (n=10) in Boston in 2018. All participants had used opioids that were not prescribed to them in the past year and experienced an opioid overdose during their lifetime. We incorporated focus group findings into our initial draft of the adapted REBOOT intervention. The adapted intervention was reviewed by 3 topical experts, and their feedback was integrated into a subsequent draft. We trained study staff on the intervention and made final refinements based on internal piloting. This paper describes the overall ADAPT-ITT process for intervention adaptation, as well as a qualitative analysis of the focus groups. Working independently, 2 authors (VMM and JA) reviewed the focus group transcripts and coded them for salient and common themes using the constant comparison method, meeting to discuss any discrepancies until consensus was reached. Codes and themes were then mapped onto the REBOOT counseling steps.

Results

Focus group findings contributed to substantial changes in the counseling intervention to better address fentanyl overdose risk. Participants described the widespread prevalence of fentanyl and said that, although they tried to avoid it, avoidance was becoming impossible. Using alone and lower opioid tolerance were identified as contributors to overdose risk. Slow shots or tester shots were acceptable and considered effective to reduce risk. Naloxone was considered an effective reversal strategy. Although calling emergency services was not ruled out, participants described techniques to prevent the arrival of police on the scene. Expert review and internal piloting improved the intervention manual through increased participant centeredness, clarity, and usability.

Conclusions

We successfully completed the ADAPT-ITT approach for an overdose prevention intervention, using theater testing with people who use opioids to incorporate the perspectives of people who use drugs into a substance use intervention. In the current crisis, overdose prevention strategies must be adapted to the context of fentanyl, and innovative strategies must be deployed, including behavioral interventions.

Trial Registration

ClinicalTrials.gov NCT03838510; https://clinicaltrials.gov/ct2/show/NCT03838510

The Community-Based Medication-First program for opioid use disorder: a hybrid implementation study protocol of a rapid access to buprenorphine program in Washington State

BACKGROUND

Opioid use disorder (OUD) is a serious health condition that is effectively treated with buprenorphine. However, only a minority of people with OUD are able to access buprenorphine. Many access points for buprenorphine have high barriers for initiation and retention. Health care and drug treatment systems have not been able to provide services to all-let alone the majority-who need it, and many with OUD report extreme challenges starting and staying on buprenorphine in those care settings. We describe the design and protocol for a study of a rapid access buprenorphine program model in six Washington State communities at existing sites serving people who are unhoused and/or using syringe services programs. This study aimed to test the effectiveness of a Community-Based Medication-First Program model.

METHODS

We are conducting a hybrid effectiveness-implementation study of a rapid access buprenorphine model of care staffed by prescribers, nurse care managers, and care navigators. The Community-Based Medication-First model of care was designed as a 6-month, induction-stabilization-transition model to be delivered between 2019 and 2022. Effectiveness outcomes will be tested by comparing the intervention group with a comparison group derived from state records of people who had OUD. Construction of the comparison group will align characteristics such as geography, demographics, historical rates of arrests, OUD medication, and health care utilization, using restriction and propensity score techniques. Outcomes will include arrests, emergency and inpatient health care utilization, and mortality rates. Descriptive statistics for buprenorphine utilization patterns during the intervention period will be documented with the prescription drug monitoring program.

DISCUSSION

Results of this study will help determine the effectiveness of the intervention. Given the serious population-level and individual-level impacts of OUD, it is essential that services be readily available to all people with OUD, including those who cannot readily access care due to their circumstances, capacity, preferences, and related systems barriers.

Best practices for community-based overdose education and naloxone distribution programs: results from using the Delphi approach

Background

Opioid-related overdose deaths have surged in the USA over the last two decades. Overdose fatalities are preventable with the timely administration of naloxone. Syringe service programs (SSP) have pioneered community-based naloxone distribution through overdose prevention and naloxone distribution (OEND) programs. There is a dearth of information with regards to best practices for community-based OEND.

Methods

We utilized a modified Delphi approach to develop a set of best practices for OEND delivery. Starting with an initial list of best practices, we engaged 27 experts, in the field of OEND programming who reviewed, made recommendations for changes, and assigned a priority to each best practice.

Results

Two rounds of input resulted in a final list of 20 best practices organized into four categories. The mean priority scores ranged from 1.17 to 2.17 (range 1 to 3). The top 5 ranked best practices were ensuring that SSP participants have low barrier, consistent, needs-based access to naloxone and that there is ample naloxone available within communities. While the remaining fifteen best practices were deemed important, they had more to do with organizational culture and implementation climate.

Conclusions

Increasing community-based OEND delivery is essential to reduce opioid overdose deaths; however, it will be insufficient to add programs without an eye toward quality of implementation and fidelity to the model upon which the evidence is based. This list of best practices summarizes the consensus among OEND experts and can serve as a tool for SSPs providing OEND programming to improve services.