Fentanyl use among street drug users in Toronto, Canada: behavioural dynamics and public health implications

Systematic review on intentional non-medical fentanyl use among people who use drugs

Objectives

Fentanyl is a highly potent opioid and has, until recently, been considered an unwanted contaminant in the street drug supply among people who use drugs (PWUD). However, it has become a drug of choice for an increasing number of individuals. This systematic review evaluated intentional non-medical fentanyl use among PWUD, specifically by summarizing demographic variance, reasons for use, and resulting patterns of use.

Methods

The search strategy was developed with a combination of free text keywords and MeSH and non-MeSH keywords, and adapted with database-specific filters to Ovid MEDLINE, Embase, Web of Science, and PsychINFO. Studies included were human studies with intentional use of non-medical fentanyl or analogues in individuals older than 13. Only peer-reviewed original articles available in English were included.

Results

The search resulted in 4437 studies after de-duplication, of which 132 were selected for full-text review. Out of 41 papers included, it was found that individuals who use fentanyl intentionally were more likely to be young, male, and White. They were also more likely to have experienced overdoses, and report injection drug use. There is evidence that fentanyl seeking behaviours are motivated by greater potency, delay of withdrawal, lower cost, and greater availability.

Conclusions

Among PWUD, individuals who intentionally use fentanyl have severe substance use patterns, precarious living situations, and extensive overdose history. In response to the increasing number of individuals who use fentanyl, alternative treatment approaches need to be developed for more effective management of withdrawal and opioid use disorder.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021272111.

Effects of fentanyl self-administration on risk-taking behavior in male rats

RATIONALE

Individuals with opioid use disorder (OUD) exhibit impaired decision making and elevated risk-taking behavior. In contrast to the effects of natural and semi-synthetic opioids, however, the impact of synthetic opioids on decision making is still unknown.

OBJECTIVES

The objective of the current study was to determine how chronic exposure to the synthetic opioid fentanyl alters risk-based decision making in adult male rats.

METHODS

Male rats underwent 14 days of intravenous fentanyl or oral sucrose self-administration. After 3 weeks of abstinence, rats were tested in a decision-making task in which they chose between a small, safe food reward and a large food reward accompanied by variable risk of footshock punishment. Following testing in the decision-making task, rats were tested in control assays that assessed willingness to work for food and shock reactivity. Lastly, rats were tested on a probabilistic reversal learning task to evaluate enduring effects of fentanyl on behavioral flexibility.

RESULTS

Relative to rats in the sucrose group, rats in the fentanyl group displayed greater choice of the large, risky reward (risk taking), an effect that was present as long as 7 weeks into abstinence. This increased risk taking was driven by enhanced sensitivity to the large rewards and diminished sensitivity to punishment. The fentanyl-induced elevation in risk taking was not accompanied by alterations in food motivation or shock reactivity or impairments in behavioral flexibility.

CONCLUSIONS

Results from the current study reveal that the synthetic opioid fentanyl leads to long-lasting increases in risk taking in male rats. Future experiments will extend this work to females and identify neural mechanisms that underlie these drug-induced changes in risk taking.

Impact of safer supply programs on injection practices: client and provider experiences in Ontario, Canada

OBJECTIVES

Fentanyl has contributed to a sharp rise in the toxicity of the unregulated drug supply and fatal overdoses in Canada. It has also changed injection practices. Injection frequency has increased as a result and so has equipment sharing and health-related risks. The aim of this analysis was to explore the impact of safer supply programs on injection practices from the perspective of clients and providers in Ontario, Canada.

METHODS

The data set included qualitative interviews with 52 clients and 21 providers that were conducted between February and October 2021 across four safer supply programs. Interview excerpts discussing injection practices were extracted, screened, coded and then grouped into themes.

RESULTS

We identified three themes, each theme corresponding to a change in injection practices. The first change was a decrease in the amount of fentanyl used and a decrease in injection frequency. The second change involved switching to injecting hydromorphone tablets instead of fentanyl. Finally, the third change was stopping injecting altogether and taking safer supply medications orally.

CONCLUSION

Safer supply programs can contribute to reducing injection-related health risks in addition to overdose risks. More specifically, they have the potential to address disease prevention and health promotion gaps that stand-alone downstream harm reduction interventions cannot address, by working upstream and providing a safer alternative to fentanyl.

Speedy Gonzales analysis method in one drop of beverage, for crimes committed with drugs from three different groups

Sertraline, zolpidem and fentanyl, are drugs with potential to be used in cases of rape, property theft and organ theft. In this study, a 15 min dilute-and-shoot analysis method was developed for the simultaneous confirmation and quantification of these drugs, using liquid chromatography tandem mass spectrometry (LC-MS/MS), in the residues of fruit juice types (mixed fruit juice, cherry juice and apricot juice), frequently consumed soft drinks. A C₁₈ phenomenex column (3 µm × 100 mm × 3 mm) was used in LC-MS/MS analysis. Validation parameters were determined by means of linearity, linear range, LOD, LOQ, repeatability and intermediate precision studies. The linearity of the method was shown up to 2.0 μgmL^-1 concentration and r² was ≥ 0.99, for each analyte. LOD and LOQ values were found in the ranges of 4.9-10.2 and 13.0-57.5 ngmL^-1 for all the analytes. Accuracies were between 74 and 126%. HorRat values calculated (between 0.57 and 0.97), revealed that the inter-day precisions (RSD% ≤ 15.5%) are acceptable. The simultaneous extraction and determination of these analytes in beverage residues in very low amounts as 100 µL is challenging because of the difficulty arising from the different chemical properties, the complexity of mixed fruit juice matrix. The method is important for hospitals (especially in emergency-toxicology cases), criminal and special laboratories from the point of determining the combined or single use of these drugs in drug facilitated crimes (DFC) and finding out the reasons of deaths related to these drugs.

Association of Illicit Fentanyl Use with Injection Risk Practices Among People who Inject Drugs

We investigated the association between fentanyl injection frequency and sharing of injection equipment among people who inject drugs. We surveyed 249 people who inject drugs in Toronto in 2019. We estimated predicted probabilities of associations between fentanyl injection frequency and injection risk practices. In prior 6 months, 117 (47.0%) of participants injected fentanyl daily, 49 (19.7%) less than daily, and 78 (31.3%) did not inject fentanyl. Participants who injected fentanyl daily shared syringes more often than those not injecting fentanyl (25.0% vs. 4.9%; χ² = 11.54, p = 0.0007). Participants who injected fentanyl daily (42.4% vs. 11.3%; χ² = 18.05, p < 0.0001) and less than daily (37.2% vs. 11.3%; χ² = 5.88 p = 0.02) shared cookers more often than those not injecting fentanyl. Participants who injected fentanyl daily (30.2% vs. 9.7%; χ² = 9.05, p = 0.003) and less than daily (30.3% vs. 9.7%; χ² = 4.11, p = 0.04) shared filters more often than those not injecting fentanyl. No differences in probabilities of sharing equipment were detected between participants who injected fentanyl daily and less than daily. People using fentanyl reported injection practices that increased risk for infectious disease transmission.

Fentanyl preference among people who use opioids in New York City

BACKGROUND

Several studies have pointed to a sub-sample of people who use drugs (PWUD) who prefer the use of non-pharmaceutical fentanyl (NPF) and, as such, pose a unique challenge for public health initiatives amidst the continued rise in overdose mortality. However, matters of drug preference and autonomy of choice remain under-studied and often misunderstood. This paper examined the experiences of PWUD reporting a preference for NPF or an NPF-heroin mixture, specifically how they navigate the perceived benefits of NPF and its established risks.

METHODS

22 in-depth interviews were conducted in New York City between March 2018 and August 2019 with PWUD who self-reported a preference for NPF or an NPF-heroin mix. Interviews were audio-recorded, and the resulting transcripts analyzed using a thematic approach.

RESULTS

Participants highlighted various factors that contributed to expressed preference for NPF or an NPF-heroin mix, including a desire to feel good, financial resources, drug availability, decreased consumer autonomy, and physiological demand. Participants reported practicing several risk reduction strategies; however, they highlighted that many, particularly carrying naloxone and always using with someone else, were difficult to implement in the context of illicit drug use.

CONCLUSIONS

Our results demonstrate participants' decreased consumer agency and greater exposure to systemic factors in the illicit markets, highlighting the need for expansion of various services, including drug checking resources and systems of outreach for PWUD who do not use intravenously. To promote tailored interventions, continued efforts in overdose prevention ought to more thoughtfully consider the context, perceptions, preferences, and behaviors of PWUD.

Trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia (2003-2015)

INTRODUCTION

Fentanyl-related overdose is an ongoing concern among countries with high prescription opioid utilisation. This study examines trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia between 2003 and 2015, overall, and by age/sex.

METHODS

This was a retrospective nationwide study of prescription dispensings and coronial records. Transdermal fentanyl utilisation was examined using Pharmaceutical Benefits Scheme dispensing records. Details of fatal fentanyl overdoses were extracted from the National Coronial Information System.

RESULTS

Transdermal fentanyl utilisation increased 5.1-fold between 2003 and 2015, from 0.28 to 1.39 mg/1000 population/day and was consistently higher among females and adults aged ≥85 years. The utilisation of higher strength patches (75 and 100 mcg/h) was more common among males aged 25-44 years. A total of 291 fatal fentanyl overdoses were recorded, increasing from no recorded deaths in 2003 to 2.23 deaths/1 000 000 population in 2015. Rates were higher among males (increasing from 0 to 3.72 deaths/1 000 000 population) and for adults aged 25-44 years (increasing from 0 to 5.34 deaths/1 000 000 population). The number of deaths/kg fentanyl dispensed was highest among males aged <25 years (45.45, 95% confidence interval 21.80-83.59). Most deaths (70.1%) involved the intravenous administration of fentanyl from transdermal patches.

DISCUSSION AND CONCLUSIONS

Rates of transdermal fentanyl utilisation and fatal fentanyl overdose across Australia increased between 2003 and 2015. Although transdermal fentanyl utilisation was consistently greater among females and older adults, rates of fatal fentanyl overdose were highest among younger males. Interventions to reduce extramedical use among this high-risk population group are necessary to minimise fentanyl-related harms.

Predictors of intentional fentanyl use: Market availability vs consumer demand

BACKGROUND

Attempts to reduce opioid overdoses have been complicated by the dramatic rise in fentanyl use. While market forces contributing to fentanyl proliferation in the illicit drug supply have increased inadvertent exposure to the drug, rising fentanyl use may also be driven by growing consumer demand. Interventions to reduce the spread of fentanyl must be based on an understanding of the motivations underlying its use.

METHODS

Data for this cross-sectional study were derived from a computerized self-administered survey completed by a convenience sample of 432 people who use illicit opioids (PWUO) recruited from methadone and detoxification programs in NJ. The anonymous survey was based on a prior qualitative study of attitudes and behaviors surrounding opioid use. Multivariate analysis identified correlates of intentional fentanyl use in the full sample and among sub-populations of white and non-white PWUO.

RESULTS

In the full sample, intentional fentanyl use was associated with white race/ethnicity, younger age, polydrug use, and a preference for the drug effects of fentanyl, which more than tripled the probability of intentional use (AOR=3.02; 95% CI=1.86-4.89; p=.000). Among whites, a preference for the fentanyl drug effects was also the strongest predictor of intentional use (AOR=5.34; 95% CI=2.78-10.28; p=.000). Among non-whites, however, exposure, not preference, was the primary driver of use, with intentional use more than doubling (AOR=2.48; 95% CI=1.04-5.91; p<.05) among those living in high fentanyl dispersion counties.

CONCLUSION

The motivations underlying fentanyl use are multifactorial and vary across populations of PWUO, indicating a need for targeted interventions to counter the increasing spread and adverse consequences of fentanyl use. In order to counteract the increasing spread and adverse consequences of fentanyl use, these findings indicate a need for harm-reduction interventions, like drug testing or supervised injection sites, that address the differing motivations for fentanyl use among PWUO.

Quantitative analysis of 20 fentanyl analogues by modified QuEChERS-LC-MS/MS in health products and transdermal patches

The spreading of narcotics especially illicit novel psychoactive substances is a continuing problem in recent years. In response to reduce the morbidity and crime related to fentanyl analogues, the accurate measurement of fentanyl analogues concentrations is significantly important in the analytical laboratories for customs checks and clinical application. In this work, ethyl acetate was selected as extraction solvent, 50 mg of PSA, 100 mg of C18, and 10 mg of GCB were optimized for purification. A modified QuEChERS extraction method followed by high performance liquid chromatography-tandem mass spectrometry with the mode of multiple reaction monitoring has been developed for the simultaneous determination of 20 fentanyl analogues in collagen peptides, slimming capsules and fentanyl transdermal patches. The limits of detection (LODs) varied from 0.004 to 0.02 μg L^-1 with relative standard deviations of 4.89-11.4 % and showed good linearity in the range of 0.02-10 μg L^-1 and 0.01-1.00 mg L^-1, respectively. The recoveries for 20 fentanyl analogues in the low (at μg L^-1 level) and high (at mg L^-1 level) concentration spiked samples were in the range of 77.7-114 % and 83.9-116 %, which demonstrated the application potential of the proposed method for the determination of fentanyl analogues with low and high concentration in real case samples. In addition, the matrix effect and the cross-reactivity were also proved to not interfere with quantitation of targeted fentanyl analogues. Thus, the developed method showed high sensitivity and good accuracy, which makes it suitable for the rapid detection of fentanyl analogues for customs and border service as well as pharmaceuticals.

Opioid overdose in the age of fentanyl: Risk factor differences among subpopulations of overdose survivors

BACKGROUND

Although fentanyl is the drug most frequently implicated in overdose deaths, the association between overdose risk and attitudes and behaviors surrounding fentanyl in opioid-using communities has remained understudied. Possible subpopulation differences in fentanyl-related overdose risk remain equally unexamined. This paper addresses these gaps by exploring the association between overdose and fentanyl-related attitudes/behaviors in three subpopulations of overdose survivors.

METHODS

In this cross-sectional study, we sampled 432 individuals who currently or recently used opioids from New Jersey methadone and acute residential detoxification programs. Using multinomial regression analysis, we compared overdose risk factors, including fentanyl-related attitudes/behaviors, of those who never overdosed with three subgroups of overdose survivors who experienced: 1. recent overdoses occurring after, but not before, fentanyl expansion; 2. past overdoses occurring before, but not after, fentanyl expansion; 3. persistent overdoses occurring before and after fentanyl expansion.

RESULTS

Forty percent of respondents had knowingly used fentanyl and 38% deliberately sought overdose-implicated drugs. Respondents with persistent overdoses represented under 10% of the sample but accounted for 44% of all lifetime overdoses (x̅ =8.03 vs. 1.71 for the full sample). This was also the only subgroup for whom PTSD (AOR=3.84; 95%CI=1.45-10.16; p=.01) and fentanyl-seeking (AOR=1.50; 95% CI=1.16-1.94; p=.01) were significant overdose risk factors. Those with recent overdoses engaged in frequent drug combining (AOR=2.28; 95% CI=1.19-6.98; p=.05), which could have led to inadvertent fentanyl use. Those with past overdoses were not at overdose risk from fentanyl-seeking or drug combining and had rates of methadone treatment comparable to rates of those with no overdoses.

CONCLUSION

Harm reduction strategies will need to address consumers' evolving drug preferences as fentanyl continues to saturate local drug markets. Targeting comprehensive interventions, including mental health treatment, to the small group of opioid users with longstanding overdose histories may reduce the burden of overdose in opioid-using communities.

Fentanyl analogs on the Swedish webforum flashback: Interest and impact of scheduling

BACKGROUND

Sweden regulates new psychoactive substances, including fentanyl analogs, individually. This reactive scheduling procedure enabled the existence of a recreational market for unscheduled fentanyl analogs sold from surface webshops. We measure the interest in 24 named fentanyl analogs and the impact of scheduling.

METHODS

We scraped posts in threads on named fentanyl analogs from the Swedish internet forum Flashback.org, 2012-2019. The sample consists of 24 threads with a total of 8761 posts. We construct five measures of interest based on duration of threads, number of posts, and number of distinct posters, and fit a non-seasonal ARMA model to test if there was a change in mean activity after scheduling.

RESULTS

Across the five measures, there was most interest in acryl fentanyl, butyr fentanyl, and acetyl fentanyl. The number of daily posts was significantly reduced in nine out of 13 threads after scheduling.

CONCLUSION

The scheduling of fentanyl analogs impacted interest on Flashback.org. The biggest effect sizes were from the narcotics scheduling of 2-Me-MAF, acryl, and acetyl fentanyl, while furanyl fentanyl saw the biggest reduction after health scheduling. The reductions were bigger for narcotics scheduling compared to health scheduling.

Evaluating networked drug checking services in Toronto, Ontario: study protocol and rationale

BACKGROUND

The increasing incidence of fatal opioid overdose is a public health crisis in Canada. Given growing consensus that this crisis is related to the presence of highly potent opioid adulterants (e.g., fentanyl) in the unregulated drug supply, drug checking services (DCS) have emerged as part of a comprehensive approach to overdose prevention. In Canada's largest city, Toronto, a network of DCS launched in 2019 to prevent overdose and overdose-related risk behaviors. This network employs mass spectrometry technologies, with intake sites co-located with supervised consumption services (SCS) at three frontline harm reduction agencies. The protocol and rationale for assessing the impact of this multi-site DCS network in Toronto is described herein. The aims of this study are to (1) evaluate the impact of DCS access on changes in and factors influencing overdose and related risk behaviors, (2) investigate the perceived capacity of DCS to prevent overdose, and (3) identify composition (qualitative and quantitative) trends in Toronto's unregulated drug supply.

METHODS

We will use a parallel-mixed-methods design with complementary data sources (including data from chemical analysis of drug samples, quantitative intake and post-test surveys, SCS, coroners, paramedic services, and qualitative interviews), followed by a meta-inference process wherein results from analyses are synthesized.

RESULTS

Whereas most DCS globally target "recreational drug users," in Toronto, this networked DCS will primarily target marginalized people who use drugs accessing frontline services, many of whom use drugs regularly and by injection. This evolution in the application of DCS poses important questions that have not yet been explored, including optimal service delivery models and technologies, as well as unique barriers for this population. Increasing information on the unregulated drug supply may modify the risk environment for this population of people who use drugs.

CONCLUSIONS

This study addresses evidence gaps on the emerging continuum of overdose prevention responses and will generate critical evidence on a novel approach to reducing the ongoing high incidence of drug-related morbidity and mortality in Canada and elsewhere.

Characteristics and circumstances of heroin and pharmaceutical opioid overdose deaths: Comparison across opioids

BACKGROUND

Although much is known about the correlates of heroin overdose, less is known about pharmaceutical opioid (PO) overdose. This study aimed to examine correlates of opioid overdose deaths by opioid and compare correlates between opioids.

METHODS

Analysis of opioid overdose deaths in Australia between 2000-2015, extracted from the National Coronial Information System (NCIS). The NCIS is an online database of deaths reportable to the coroner, and contains coroner's findings, autopsy and toxicology reports. Deaths were categorized into mutually exclusive groups: 1) Heroin deaths; and 2) PO deaths (excluding heroin). PO deaths were examined by individual opioid.

RESULTS

There were 10,795 opioid overdose deaths over the study period. Relative to deaths occurring in major cities, deaths in regional/remote areas had 15.2 (95 % CI: 11.5-20.2) times the risk of being attributed to pharmaceutical fentanyl than heroin. Relative to deaths among people without a recorded history of chronic pain, deaths among people with a recorded history of chronic pain had a 1.9-10.7-fold increased risk of the death being attributed to POs than heroin. Deaths among people with a recorded history of substance use problems where the opioid was injected prior to death had 7.2 and 1.7 times the risk of being attributed to methadone and pharmaceutical fentanyl (respectively) than heroin.

CONCLUSIONS

Findings suggest the need to: educate PO consumers about the risks of overdose at the time of prescribing; increase coverage and engagement in opioid dependence treatment (particularly in regional/remote areas); and increase uptake of take-home naloxone to reduce opioid overdose mortality.

Associations between perceived illicit fentanyl use and infectious disease risks among people who inject drugs

BACKGROUND

Over the last several years, fentanyl has been introduced into the illicit drug supply in the United States. While the impact of fentanyl on overdose fatalities is clear, the increase in fentanyl use may also be affecting drug use practices with implications for infectious disease transmission. We conducted a cross-sectional survey to explore associations of perceived illicit fentanyl use with opioid use frequency, injection frequency and syringe sharing among people who inject drugs in two California cities.

METHODS

People who inject drugs (PWID) were recruited from community settings in Los Angeles and San Francisco, CA from June 2017 to September 2018. Multivariable logistic regression was used to explore adjusted associations between perceived illicit fentanyl use and high frequency opioid use, high frequency injection and syringe sharing.

RESULTS

Among the 395 study participants, the median age of participants was 44 years; 74% of participants were cisgender male; 73% reported to be homeless; 61% lived in San Francisco and 39% in Los Angeles. The prevalence of perceived illicit fentanyl use in the past six months was 50.4% (95% confidence interval (CI): 45.4%-55.3%) among PWID. Findings from our adjusted logistic regression models suggested that people reporting perceived illicit fentanyl use had a greater odds of high frequency opioid use (adjusted odds ratio (aOR) = 2.36; 95% CI: 1.43-3.91; p = 0.001), high frequency injection (aOR = 1.84; 95% CI: 1.08-3.13; p = 0.03) and receptive syringe sharing (aOR = 2.16; 95% CI: 1.06-4.36; p = 0.03), as compared to people using heroin and other street drugs but not fentanyl.

CONCLUSION

People reporting perceived illicit fentanyl use were at increased risk for injection-related infectious disease risks. Actions must be taken to reduce these risks, including improved access to syringe service programs and opioid treatment and consideration of innovative approaches, such as supervised consumption services.

Preference for drugs containing fentanyl from a cross-sectional survey of people who use illicit opioids in three United States cities

BACKGROUND

Death from fentanyl-related overdose is now a leading cause of mortality among US adults. We sought to characterize fentanyl preference among street-based people who use drugs (PWUD).

METHODS

Cross-sectional surveys were administered to PWUD (N = 308) who illicitly used heroin or prescription opioids in the prior six months. Recruitment occurred in 2017 in three US east coast cities with high overdose mortality: Baltimore, Boston, and Providence. Our main outcome was preference for fentanyl (yes/no); exposures included sociodemographics, drug use, and overdose history. Pearson's χ2, Shapiro-Wilk-Mann rank-sum tests, and tiered log-binomial regression determined sociodemographic and exposure-related factors associated with fentanyl preference.

RESULTS

Preference for nonmedical use of fentanyl was reported by 27% (n = 83) of the sample. Fentanyl preference was associated with non-Hispanic white race (adjusted risk ratio (ARR) = 1.68, 95% confidence interval (CI):1.18-2.40), daily illicit drug use (aRR = 2.2, CI:1.71-2.87), and overdose ≥1 year ago (aRR = 1.33, CI:1.18-1.50). Age (in decades; aRR = 0.77, CI:0.61-0.98) and overdose <1 year ago (aRR = 0.92, CI:0.87-0.97) were associated with a decreased likelihood of preference. In our model excluding sociodemographics, initiating opioid use with non-prescribed opioids was associated with fentanyl preference (aRR = 1.48, CI:1.26-1.73).

CONCLUSION

In three cities with high levels of opioid use and overdose, a quarter of street based PWUD reported preferring fentanyl. An opioid use age cohort effect and disproportionate access to prescription opioids by race could be contributing to preference. Frequency of opioid use, not route of administration, was associated with preference. Our data demonstrate the need to consider preferences for fentanyl when targeting services and interventions for PWUD.

Characteristics of opioid-maintained clients smoking fentanyl patches: The importance of confirmatory drug analysis illustrated by a case series and mini-review

The increase in opioid prescribing in many European countries over the last decade has raised concerns about associated diversion, overdose, and mortality. Fentanyl is one of these synthetic opioids that is typically prescribed as a transdermal patch for pain that requires continuous pain relief and has been the focus of investigation due to reports of overdose and death. We report a case series of 14 drug addiction treatment entrants, who entered treatment in a service located in the region of Southern Denmark from August 2015 to December 2015 for smoking fentanyl patches. Clients presented with difficulties breathing and pains in the lungs. The clients had a history of past opioid use, including heroin. Relapses resulted in treatment disengagement. Immunoassays for fentanyl were used in the service. In some cases, false negative results occurred. Clients' urine samples were subsequently analysed in a collaborating laboratory. Seven clients tested positive for fentanyl. One client was positive for both fentanyl and heroin. Analyses were also positive for other opioids and metabolites in 6 clients, predominantly codeine and oxycodone. Results from confirmatory analysis contributed to clearer insights into clients' drug histories, which facilitated personalised care plans consisting of opioid agonist therapy informed by confirmed drug use. In Denmark, prescription levels of fentanyl are high, which has been accompanied by observations of diversion and smoking in a smaller population. In addition to revision of inappropriate prescribing to reduce diversion, we recommend increased reliance upon confirmatory drug analysis in the addiction treatment sector in Denmark.

A Descriptive Examination of Nonmedical Fentanyl Use in the United States: Characteristics of Use, Motives, and Consequences

Little is currently known about nonmedical fentanyl use (NFU; that is, use of illicit or pharmaceutically produced fentanyl without a prescription or in ways other than prescribed) despite increases in prevalence and consequences (e.g., overdose, fatality). Individuals with a lifetime history of NFU ( N = 122) in the United States completed an online survey assessing demographics and factors related to use. Results revealed diversion of prescriptions, unintentional use of illicit fentanyl, and high co-occurrence of mental illness and other illicit substance use among users. Commonly reported motives reflected negative/positive reinforcement (e.g., to relieve stress, to get high) and relieving pain/physical discomfort, regardless of frequency of use. More severe consequences (e.g., increased tolerance, withdrawal) were reported among high frequency users. This descriptive examination of NFU may aid in the identification of individuals at-risk for use, promote an understanding of reasons for use, and guide prevention and intervention developments.

Intravenous fentanyl use among people who inject drugs in Australia

INTRODUCTION AND AIMS

There is a current epidemic of pharmaceutical opioid (PO) misuse, particularly fentanyl and fentanyl analogues, globally. Fentanyl is a highly potent synthetic opioid with rapid onset and significantly higher risk of overdose compared with other opioids. Contexts and correlates of fentanyl use among people who inject drugs (PWID) in Australia are under-researched.

DESIGN AND METHODS

The Australian Needle Syringe Program Survey is conducted annually. Consenting PWID complete a self-administered questionnaire and provide a capillary dried blood spot for human immunodeficiency virus and hepatitis C virus antibody testing. Bivariate and multivariate logistic regressions determined correlates of recent (last 6 months) fentanyl injection in 2014.

RESULTS

Recent fentanyl injection was reported by 8% (n = 193) of the total sample. Among the 848 PWID who recently injected POs, 23% injected fentanyl. Compared with PO injectors who had not injected fentanyl, those who had injected fentanyl were significantly more likely to identify as Indigenous Australian [adjusted odds ratio (AOR) 1.61; 95% confidence interval (CI) 1.04, 2.51; P = 0.034], inject daily or more frequently (AOR 1.92; 95% CI 1.30, 2.83; P = 0.005), inject in public (AOR 1.43; 95% CI 1.01, 2.02; P = 0.042) and to have overdosed in the past year (AOR 2.16; 95% CI 1.48, 3.13; P < 0.001), but were significantly less likely to receptively share syringes (AOR 0.56; 95% CI 0.36, 0.87; P = 0.010).

DISCUSSION AND CONCLUSIONS

Fentanyl injectors in Australia are significantly more likely to identify as Indigenous, report frequent injection, inject in public and experience overdose. Increased access to harm reduction interventions, including naloxone distribution, wheel filters and supervised injection facilities, are likely to benefit this population.

Post-mortem review of fentanyl-related overdose deaths among identified drug users in Southern Bavaria, Germany, 2005-2014

BACKGROUND

Two decades ago, there were only single case reports on deaths in Europe following the consumption of illicitly manufactured fentanyl by problem drug users. Today, lethal fentanyl intoxication is now no longer a rarity. Since 2005, a rapid increase of lethal fentanyl-related intoxications in the drug scene has been observed at the Institute of Legal Medicine, Ludwig Maximilians University, Munich. We hypothesized that this rise is the result of the launch of fentanyl matrix patches in Germany in 2004, their broad acceptance, their diversion from the regulated supply chain, and incautious prescription by medical care providers.

METHODS

Post-mortem toxicological reports were reviewed for lethal fentanyl-related intoxications between 2004 und 2014. Blood and tissue samples were tested by GC/MS or LC-MS/MS. The results of police investigations, autopsy reports, and the database of the Institute of Legal Medicine, LMU, were analysed to identify problem drug users and to detect the source of fentanyl as well as the routes of administration.

RESULTS

Between 2005 and 2014, 242 overdose victims with post-mortem toxicological detection of fentanyl were found. In the majority of cases, fentanyl matrix patches were the source of fentanyl.

CONCLUSION

The onset of fentanyl-related deaths coincided with the launch of transdermal fentanyl matrix patches in Germany in 2004. Several approaches, such as providing drug users with information on the possible risks of fentanyl consumption, education of medical caregivers, and also monitoring of the prescription of fentanyl patches, are required to reduce the number of fentanyl-related deaths in drug addicts.

Exposure to fentanyl-contaminated heroin and overdose risk among illicit opioid users in Rhode Island: A mixed methods study

BACKGROUND

Illicit fentanyl use has become wide spread in the US, causing high rates of overdose deaths among people who use drugs. This study describes patterns and perceptions of fentanyl exposure among opioid users in Rhode Island.

METHODS

A mixed methods study was conducted via questionnaire with a convenience sample of 149 individuals using illicit opioids or misusing prescription opioids in Rhode Island between January and November 2016. Of these, 121 knew of fentanyl and reported known or suspected exposure to fentanyl in the past year. Semi-structured interviews were conducted with the first 47 participants.

RESULTS

Study participants were predominantly male (64%) and white (61%). Demographic variables were similar across sample strata. Heroin was the most frequently reported drug of choice (72%). Self-reported exposure to illicit fentanyl in the past year was common (50.4%, n=61). In multivariate models, regular (at least weekly) heroin use was independently associated with known or suspected fentanyl exposure in the past year (adjusted prevalence ratio (APR)=4.07, 95% CI: 1.24-13.3, p=0.020). In interviews, users described fentanyl as unpleasant, potentially deadly, and to be avoided. Participants reporting fentanyl exposure routinely experienced or encountered non-fatal overdose. Heroin users reported limited ability to identify fentanyl in their drugs. Harm reduction strategies used to protect themselves from fentanyl exposure and overdose, included test hits, seeking prescription opioids in lieu of heroin, and seeking treatment with combination buprenorphine/naloxone. Participants were often unsuccessful in accessing structured treatment programs.

CONCLUSION

Among illicit opioid users in Rhode Island, known or suspected fentanyl exposure is common, yet demand for fentanyl is low. Fentanyl-contaminated drugs are generating user interest in effective risk mitigation strategies, including treatment. Responses to the fentanyl epidemic should be informed by the perceptions and experiences of local users. The rapid scale-up of buprenorphine/naloxone provision may slow the rate of fentanyl-involved overdose deaths.

Safety of fentanyl initiation according to past opioid exposure among patients newly prescribed fentanyl patches

BACKGROUND

Although a convenient opioid delivery system, transdermal fentanyl patches have caused several deaths and resulted in safety warnings reminding prescribers that fentanyl patches should be prescribed only for patients who have adequate prior exposure to opioids. We conducted a longitudinal analysis of the safety of fentanyl initiation by examining past opioid exposure among patients newly prescribed fentanyl patches.

METHODS

We identified all patients in the province of Manitoba who were newly prescribed fentanyl patches between Apr. 1, 2001, and Mar. 31, 2013. We converted all prior opioid use to oral morphine equivalents and determined the average daily dose in the 7-30 days before initial fentanyl patch use. Fentanyl initiation was considered unsafe if the patient's pre-fentanyl opioid exposure was below the recommended level.

RESULTS

We identified 11 063 patients who began using fentanyl patches during the study period. Overall, fentanyl initiation was deemed unsafe in 74.1% of cases because the patient's prior opioid exposure was inadequate. Women and patients 65 years of age and older were more likely than men and younger patients, respectively, to have inadequate prior opioid exposure (p < 0.001 for each comparison). The proportion of patients who had unsafe prescriptions for fentanyl patches decreased significantly over the study period, from 87.0% in 2001 to 50.0% in 2012 (p < 0.001).

INTERPRETATION

The safety of fentanyl initiation improved over the study period, but still half of fentanyl patch prescriptions were written for patients with inadequate prior opioid exposure. Review of prior opioid exposure may be a simple but important way to improve the safe use of fentanyl patches.

Transdermal patches: history, development and pharmacology

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems.

In vitro release of fentanyl from transdermal patches in gastric and intestinal fluid

CONTEXT. Fentanyl patches are intended for transdermal use to treat pain. However, these patches have been abused by ingestion, offering a unique mode of drug delivery with unknown drug release characteristics. OBJECTIVES. In vitro fentanyl release from patches in simulated gastric and intestinal fluid was evaluated. MATERIALS AND METHODS. Ten 75 mcg/hr fentanyl transdermal patches (Mylan Pharmaceuticals Inc., Morgantown, WV), simulated gastric fluid without enzymes, and USP simulated intestinal fluid (Ricca Chemical Company, Arlington, TX) were obtained. Each fentanyl patch was placed into either 100 mL of simulated gastric fluid or 100 mL of simulated intestinal fluid. Flasks were agitated at 24 rpm while incubated at 36.8°C. Fluid was sampled at time zero and 5, 15, 30, 60, 120, and 180 min after submersion. Fentanyl was assayed using ultra performance liquid chromatography coupled with tandem mass spectrometry (AIT Laboratories, Indianapolis, IN). RESULTS. An average of 239 mcg and 1,962 mcg of fentanyl was released into gastric fluid and 338 mcg and 3,139 mcg into intestinal fluid in 5 min and 3 h, respectively. An average of 26% and 41% of 7.65 mg of fentanyl contained within the 75 mcg/hr patch was released into gastric and intestinal fluid in 3 h, respectively (p = 0.169, Student's t-test). DISCUSSION. Our results demonstrate fentanyl release within 5 min of submersion. CONCLUSION. These results help support the potential rapid onset of clinical compromise reported and are relevant to the design of future pharmacokinetic studies of fentanyl release from transdermal patches.