Temporal and regional associations between fentanyl concentrations in the unregulated drug supply and drug-related mortality in British Columbia, Canada.

Fentanyl toxicity is the leading cause of unnatural death in British Columbia (BC), Canada, driven in part by fentanyl’s potency and unpredictable, highly variable concentration in unregulated drug samples. This study aims to identify emerging trends and the possible relationship between fentanyl concentrations in community drug samples and the postmortem blood of drug-toxicity decedents. Data for this ecological study were derived from Vancouver, BC community drug-checking sites and the BC Coroners Service. We analyzed fentanyl concentrations of opioid drug-checking samples alongside postmortem blood fentanyl concentrations from unintentional drug-toxicity decedents in which fentanyl contributed. The study period was January 2018 through December 2022. Monthly median fentanyl concentrations of drug-checking samples were compared to postmortem blood concentrations using generalized additive models. The primary time-series model, adjusted for potential confounders, did not identify a statistically significant association between drug-checking and postmortem concentrations (edf = 3.58, χ2 = 8.48, P = 0.104); however, a sensitivity analysis excluding extreme values revealed a significant nonlinear association (edf = 3.91, χ2 = 11.71, P = 0.038). Fentanyl concentrations in both the unregulated drug supply and postmortem blood changed over time with the two being mutually associated: as median fentanyl concentrations in opioid drug-checking samples increased, postmortem blood fentanyl concentrations generally decreased. Further research into complexities of the drug supply, changing substance use patterns, and rates of fentanyl exposure among opioid-naïve individuals may explain this nonlinear trend and inform strategies to abate the ongoing crisis.

Fentanyl Concentration in Drug Checking Samples and Risk of Overdose Death in Vancouver, Canada

North America has been contending with an unregulated street drug supply in which opioids are often adulterated with illicitly manufactured fentanyl. The unpredictability of composition may result in an increased risk of overdose due to unexpected elevated concentrations of the high-potency drug. Using data from a community-based drug-checking project, we evaluated trends in fentanyl concentration of illicit opioids in the context of an overdose epidemic. Using a quantification model for fentanyl hydrochloride, historical Fourier-transform infrared spectra from opioid drug-checking samples were analyzed to determine fentanyl concentrations. Median monthly fentanyl concentrations were plotted, and polynomial and autoregressive time-series analyses were performed to examine trends over time. A total of 3,621 fentanyl-positive samples were included in the study, spanning November 2017 to December 2019. Monthly median fentanyl concentrations ranged from 4.5% to 10.4%. Time-series analyses indicated that a third-degree polynomial model fit the data well (R2= 0.639), suggesting a cyclical pattern in median concentration over time. Notably, absolute variance in fentanyl concentration decreased by an average 0.1% per month (P< 0.001). Future research should explore the relationship between fentanyl concentration and overdose to identify potential targeted harm-reduction interventions that can respond to changes in observed fentanyl concentration.

Tobias et al. (Am J Epidemiol. 2022;191 (2):241–247) present a novel analysis of time trends in fentanyl concentrations in the unregulated drug supply in British Columbia, Canada. The preexisting knowledge about unregulated drugs had come from law-enforcement seizures and postmortem toxicology. As both of these data sources are subject to selection bias, large-scale drug-checking programs are poised to be a crucial component of the public health response to the unrelenting increase in overdose in North America. As programs expand, we offer 2 guiding principles. First, the primary purpose of these programs is to deliver timely results to people who use drugs to mitigate health risks. Second, innovation is needed to go beyond criminal justice paradigms in laboratory analysis for a more nuanced understanding of health concerns. We provide examples of the role adulterants play in our understanding of drug harms. We also describe the applications and limitations of common laboratory assays, with implications for epidemiologic surveillance. While the research and direct service teams in British Columbia have taken groundbreaking steps, there is still a need to establish best practices for communicating results to sample donors in an approachable yet nonalarmist tone.

Development and validation of a fentanyl quantification model for drug checking services

Not just fentanyl: Understanding the complexities of the unregulated opioid supply through results from a drug checking service in British Columbia, Canada.

A rejoinder to Brooks etal. "Response to operational and contextual barriers to accessing supervised consumption services in two Canadian cities".

Impact of having a regular drug dealer on obtaining drug checking results consistent with expectations during a drug toxicity crisis in a Canadian setting.

An outbreak of novel psychoactive substance benzodiazepines in the unregulated drug supply: Preliminary results from a community drug checking program using point-of-care and confirmatory methods.

BackgroundThe well-being of people who use drugs (PWUD) continues to be threatened by substances of unknown type or quantity in the unregulated street drug supply. Current efforts to monitor the drug supply are limited in population reach and comparability. This restricts capacity to identify and develop measures that safeguard the health of PWUD. This study describes the development of a low-barrier system for monitoring the contents of drugs in the unregulated street supply. Early results for pilot sites are presented and compared across regions.MethodsThe drug content monitoring system integrates a low-barrier survey and broad spectrum urine toxicology screening to compare substances expected to be consumed and those actually in the drug supply. The system prototype was developed by harm reduction pilot projects in British Columbia (BC) and Montreal with participation of PWUD. Data were collected from harm reduction supply distribution site clients in BC, Edmonton and Montreal between May 2018–March 2019. Survey and urine toxicology data were linked via anonymous codes and analyzed descriptively by region for trends in self-reported and detected use.ResultsThe sample consisted of 878 participants from 40 sites across 3 regions. Reported use of substances, their detection, and concordance between the two varied across regions. Methamphetamine use was reported and detected most frequently in BC (reported: 62.8%; detected: 72.2%) and Edmonton (58.3%; 68.8%). In Montreal, high concordance was also observed between reported (74.5%) and detected (86.5%) cocaine/crack use. Among those with fentanyl detected, the percentage of participants who used fentanyl unintentionally ranged from 36.1% in BC, 78.6% in Edmonton and 90.9% in Montreal.ConclusionsThis study is the first to describe a feasible, scalable monitoring system for the unregulated drug supply that can contrast expected and actual drug use and compare trends across regions. The system used principles of flexibility, capacity-building and community participation in its design. Results are well-suited to meet the needs of PWUD and inform the local harm reduction services they rely on. Further standardization of the survey tool and knowledge mobilization is needed to expand the system to new jurisdictions.

BackgroundIncreases in fatal overdoses were observed coinciding with the COVID-19 pandemic across the USA and Canada. Hypothesised explanations include pandemic-attributable healthcare service disruption, social isolation and illicit drug market disruption....

ABSTRACTDrug checking services provide individuals who use drugs with the ability to test samples of their drugs for the presence of highly potent substances. However, there has been recent concern about whether the existing repertoire of point-of-care drug checking technologies, such as immunoassay strips and Fourier-transform infrared spectroscopy (FTIR), are adequate in identifying substances in the unregulated drug supply. Carfentanil and nitazene opioids, substances that are even more potent than fentanyl in vitro, have been found in the unregulated supply in North America and pose a challenge to our existing drug checking strategy. For example, etizolam has recently permeated the unregulated drug supply in North America, and has demonstrated the ability to evade point-of-care drug checking technologies. In response to the incessantly changing nature of the unregulated supply, we argue that drug checking technologies and service delivery models must continuously adapt alongside constantly changing drug markets. We provide two examples of emerging technologies, paper spray-mass spectrometry and surface-enhanced Raman spectroscopy, which address many of the shortcomings of existing technologies. For both technologies, we discuss their feasibility, where they can be offered, their advantages, and how they address gaps in our existing technologies. We contend that these technologies, and other emerging technologies, can be integrated into a future approach to drug checking that flexibly uses different technologies and service delivery methods to adapt to changes in the drug supply.

The emergence of fentanyl and its analogues have contributed to a drastic rise in overdose-related mortality in recent years. The objective of this study was to determine the number of drug checking samples containing fentanyl and fentanyl analogues using both point of care and confirmatory drug checking technologies. Point-of-care drug checking data, using a combination of fentanyl immunoassay strips and Fourier-transform infrared spectroscopy (FTIR), were collected at harm reduction sites in Vancouver and Surrey, British Columbia. Based on current recommendations from the British Columbia Centre on Substance Use Drug Checking Project, a subset of these samples was sent for confirmatory analysis using quantitative nuclear resonance spectroscopy, gas chromatography-mass spectrometry and/or liquid chromatography-mass spectrometry. A total of 22,916 samples were tested using FTIR and fentanyl immunoassay strips, of which 6125 (29%) were positive for fentanyl and/or fentanyl analogues. FTIR identified a fentanyl analogue in five samples (all carfentanil). Of the 1467 samples sent for confirmatory analysis, fentanyl was identified in 855 (58%) and fentanyl analogues in 85 (6%), including: carfentanil (n=56), acetyl fentanyl (n=15), furanyl fentanyl (n=9) and cyclopropyl fentanyl (n=5). Our research found that FTIR does not consistently distinguish between fentanyl and its analogues at point of care and that highly sensitive confirmatory drug checking technologies are needed to identify fentanyl analogues. These findings underscore the limitations of current drug checking technologies and the importance of using both point of care and confirmatory drug checking initiatives for monitoring changes in the drug supply.

Community-based drug checking services have scaled up in response to the unregulated drug toxicity crisis across North America. We sought to assess the relationship between the detection of unexpected active drugs in a drug checking sample and subsequent engagement in risk reduction practices. We used data from a cross-sectional study of people who used community-based drug checking services in British Columbia, Canada (March 2020-July 2024). We constructed multivariable logistic regression models to examine the relationship between the detection of unexpected active drugs (i.e., compounds that have psychoactive properties) in samples brought for analysis (using combination Fourier-transform infrared spectroscopy and immunoassay strips) and engagement in subsequent risk reduction practices (e.g., dose reduction, disposal of the drug). In total, 447 individuals were included: 174 (38.9%) reported detection of unexpected active drugs in their drug checking sample with the most common being benzodiazepines in expected opioid samples. The most common risk reduction behaviours were to dispose of the drug without using it (n = 24) and taking a smaller dose (n = 11). Through multivariable logistic regression, we found a positive association between detection of unexpected active drugs and engagement in risk reduction practices (adjusted odds ratio = 2.24; 95% confidence interval: 1.30-3.87). Individuals who detected unexpected active drugs in their sample had higher odds of engaging in risk reduction practices. These findings highlight the potential of drug checking services as a harm reduction tool within a suite of services offered to combat the unpredictable and unregulated drug supply.

The purpose of this study was to compare blood fentanyl concentrations in fentanyl-related deaths with fentanyl concentrations found incidentally at autopsy, as well as with fentanyl concentrations found in hospitalized patients receiving fentanyl. Between the years 1997 to 2005, 23 fentanyl-positive postmortem cases were identified. Nineteen of 23 (82.6%) cases were deemed to be drug overdoses. Fentanyl alone was responsible for 8 of the 19 (42.1%) overdose deaths. Mean and median fentanyl concentrations were 36 (SD 38) microg/L and 22 microg/L, respectively, range 5-120 microg/L. Seven of the cases were accidental, one undetermined. The remaining 11 of the 19 (57.9%) cases were mixed drug overdoses. Fentanyl concentrations in these cases were 31 (SD 46) microg/L, range 5-152 microg/L. All of the mixed drug overdoses were determined to be accidental. Four cases where fentanyl was considered an incidental postmortem finding were determined to be natural deaths. In hospitalized inpatients (n = 11) receiving fentanyl 2 of the patients receiving fentanyl for chronic pain for more than 3 months had concentrations of 8.5 microg/L and 9.9 microg/L. The other nine inpatient concentrations were less than 4 microg/L. In conclusion, blood fentanyl concentrations found in cases where fentanyl alone was determined to be the cause of death were similar to cases where fentanyl was part of a mixed drug overdose. There was also considerable overlap between fentanyl concentrations in fentanyl-related overdose deaths compared to hospitalized patients being treated for chronic pain. Fentanyl concentrations in postmortem cases must be interpreted in the context of the deceased's past medical history and autopsy findings.