Substance use patterns associated with recent exposure to fentanyl among people who inject drugs in Vancouver, Canada: A cross-sectional urine toxicology screening study

The Impact of Drugs and Substance Abuse on Viral Pathogenesis-A South African Perspective

Illicit drug and alcohol abuse have significant negative consequences for individuals who inject drugs/use drugs (PWID/UDs), including decreased immune system function and increased viral pathogenesis. PWID/UDs are at high risk of contracting or transmitting viral illnesses such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). In South Africa, a dangerous drug-taking method known as "Bluetoothing" has emerged among nyaope users, whereby the users of this drug, after injecting, withdraw blood from their veins and then reinject it into another user. Hence, the transmission of blood-borne viruses (BBVs) is exacerbated by this "Bluetooth" practice among nyaope users. Moreover, several substances of abuse promote HIV, HBV, and HCV replication. With a specific focus on the nyaope drug, viral replication, and transmission, we address the important influence of abused addictive substances and polysubstance use in this review.

Implementation opportunities and challenges to piloting a community-based drug-checking intervention for sexual and gender minority men in Vancouver, Canada: a qualitative study

BACKGROUND

In response to the overdose crisis, a collaborative group of two community-based organizations, a health authority and a research institute in Vancouver, Canada, implemented a pilot community-based drug checking (CBDC) intervention for sexual and gender minority (SGM) men. This study identified key factors that influenced the implementation of the CBDC intervention, including opportunities and challenges.

METHODS

We conducted semi-structured interviews with seven pertinent parties involved in the CBDC, including policymakers, researchers and representatives from community-based organizations. These interviews were coded and analyzed using domains and constructs of the Consolidated Framework for Implementation Research.

RESULTS

While drug-related stigma was identified as a challenge to deliver drug checking services, participants described the context of the overdose crisis as a key facilitator to engage collaboration between relevant organizations (e.g., health authorities, medical health officers, community organizations) to design, resource and implement the CBDC intervention. The implementation of the CBDC intervention was also influenced by SGM-specific needs and resources (e.g., lack of information about the drug supply). The high level of interest of SGM organizations in providing harm reduction services combined with the need to expand drug checking into community spaces represented two key opportunities for the CBDC intervention. Here, SGM organizations were recognized as valued partners that fostered a broader culture of harm reduction. Participants' emphasis that knowing the composition of one's drugs is a "right to know", particularly in the context of a highly contaminated illicit drug market, emerged as a key implementation factor. Lastly, participants emphasized the importance of involving SGM community groups at all stages of the implementation process to ensure that the CBDC intervention is appropriately tailored to SGM men.

CONCLUSIONS

The context of the overdose crisis and the involvement of SGM organizations were key facilitators to the implementation of a drug checking intervention in SGM community spaces. This study offers contextualized understandings about how SGM knowledge and experiences can contribute to implement tailored drug checking interventions.

All-cause mortality before and after DAA availability among people living with HIV and HCV: An international comparison between 2010 and 2019

BACKGROUND

Among people living with HIV and hepatitis C virus (HCV), people who inject drugs (PWID) have historically experienced higher mortality rates. Direct-acting antivirals (DAA), which have led to a 90 % HCV cure rate independently of HIV co-infection, have improved mortality rates. However, DAA era mortality trends among PWID with HIV/HCV remain unknown. Using data from the International Collaboration on Hepatitis C Elimination in HIV Cohorts (InCHEHC), we compared pre/post-DAA availability mortality changes in three groups: PWID, men who have sex with men (MSM), and all other participants.

METHODS

We included InCHEHC participants with HIV/HCV followed between 2010 and 2019 in Canada, France, the Netherlands, Spain, and Switzerland. All-cause mortality hazard was compared in the three groups, using Cox proportional hazards regression models adjusted for sex, age, advanced fibrosis/cirrhosis, and pre/post DAA availability.

RESULTS

Of the 11,029 participants, 76 % were men, 46 % were PWID, baseline median age was 46 years (interquartile range [IQR] = 40;51), and median CD4 T-cell count was 490 cells/mm3 (IQR = 327;689). Over the study period (median follow-up = 7.2 years (IQR = 3.7;10.0)), 6143 (56 %) participants received HCV treatment, 4880 (44 %) were cured, and 1322 participants died (mortality rate = 1.81/100 person-years (PY) [95 % confidence interval (CI)=1.72-1.91]). Overall, PWID had higher mortality rates than MSM (2.5/100 PY [95 % CI = 2.3-2.6] vs. 0.8/100 PY [95 % CI = 0.7-0.9], respectively). Unlike women with other transmission modes, those who injected drugs had a higher mortality hazard than men who did not inject drugs and men who were not MSM (adjusted Hazard-Ratio (aHR) [95 % CI] = 1.3[1.0-1.6]). Post-DAA availability, mortality decreased among MSM in the Netherlands, Spain, and Switzerland and increased among PWID in Canada (aHR [95 % CI] = 1.73 [1.15-2.61]).

CONCLUSION

Post-DAA availability, all-cause mortality did not decrease in PWID. Determinants of cause-specific deaths (drug-related, HIV-related, or HCV-related) need to be identified to explain persistently high mortality among PWID in the DAA era.

Prevalence of fentanyl in methamphetamine and cocaine samples collected by community-based drug checking services

BACKGROUND

Overdose deaths involving stimulants and opioids simultaneously have raised the specter of widespread contamination of the stimulant supply with fentanyl.

METHODS

We quantified prevalence of fentanyl in street methamphetamine and cocaine, stratified by crystalline texture, analyzing samples sent voluntarily to a public mail-in drug checking service (May 2021-June 2023). Samples from 77 harm reduction programs and clinics originated in 25 US states. Sample donors reported expected drug and physical descriptions. Substances were identified by gas chromatography-mass spectrometry. Negative binomial models were used to calculate fentanyl prevalence, adjusting for potential confounders related to sample selection. We also examined if xylazine changed donors' accuracy of detecting fentanyl.

RESULTS

We analyzed 718 lab-confirmed samples of methamphetamine (64%) and cocaine (36%). The adjusted prevalence of fentanyl was 12.5% (95% CI: 2.2%, 22.9%) in powder methamphetamine and 14.8% (2.3%, 27.2%) in powder cocaine, with notable geographic variation. Crystalline forms of both methamphetamine (Chisq=57, p<0.001) and cocaine (Chisq=18, p<0.001) were less likely to contain fentanyl: less than 1% of crystal methamphetamine (2/276) and no crack cocaine (0/53). Heroin was present in 6.6% of powder cocaine samples. Xylazine reduced donors' ability to detect fentanyl, with correct classification dropping from 92% to 42%.

CONCLUSIONS

Fentanyl was detected primarily in powder forms of methamphetamine and cocaine. Recommended interventions include expanding community-based drug checking, naloxone and fentanyl test strip distribution for people who use stimulants , and supervised drug consumption sites. New strategies to dampen variability in street drug composition are needed to reduce inadvertent fentanyl exposure.

Food insecurity during the COVID-19 pandemic who use drugs in Vancouver, Canada

OBJECTIVE

To examine prevalence and factors associated with food insecurity among people who use drugs (PWUD) during the first year of the COVID-19 pandemic and the overdose crisis.

DESIGN

This cross-sectional study employs multivariable logistic regression to identify factors associated with self-reported food insecurity.

PARTICIPANTS

PWUD who are part of three community-recruited cohorts.

SETTING

Interviews conducted in Vancouver, Canada, via phone between July and November 2020 in adherence to COVID-19 safety procedures.

RESULTS

Among 765 participants, including 433 (56·6 %) men, eligible for this study, 146 (19·1 %; 95 % CI: 16·3 %, 21·9 %) reported food insecurity in the past month. Of the participants reporting food insecurity, 114 (78·1 %) reported that their hunger levels had increased since the beginning of the pandemic. In multivariable analyses, factors independently and positively associated with food insecurity included: difficulty accessing health or social services (adjusted OR (AOR) = 2·59; 95 % CI: 1·60, 4·17); having mobility difficulties (AOR = 1·59; 95 % CI: 1·02, 2·45) and engaging in street-based income generation (e.g. panhandling and informal recycling) (AOR = 2·31; 95 % CI: 1·45, 3·65).

CONCLUSION

Approximately one in five PWUD reported food insecurity during this time. PWUD with mobility issues, who experienced difficulty accessing services and/or those engaged in precarious street-based income generation were more likely to report food insecurity. Food security is paramount to the success of interventions to prevent COVID-19 and drug toxicity deaths. These findings suggest a need for a more unified state response to food insecurity that prioritises and incorporates accessibility and autonomy of the communities they serve.

Outpatient Rapid Titration of Slow Release Oral Morphine for the Treatment of Opioid Use Disorder in a Canadian Setting: A Case Series

INTRODUCTION

In the midst of unprecedented opioid overdose deaths, opioid agonist therapy induction strategies that allow for rapid titration to therapeutic doses for individuals at high risk of overdose are needed. Slow release oral morphine (SROM) is an effective treatment for opioid use disorder; however, current guideline-recommended titration strategies require weeks to achieve therapeutic dose for individuals with high opioid tolerance. Individuals may be lost to care or experience overdose due to ongoing use of unregulated opioids during this time. After years of experience titrating SROM doses rapidly in the inpatient setting, we developed a protocol using short-acting morphine (MOS) to allow for rapid SROM titration in the outpatient setting.

CASES

Patients (n = 4) were eligible if they met the criteria for opioid use disorder and had evidence of high opioid tolerance. Patients received supervised MOS doses in the outpatient setting, which were consolidated into a 12-hour extended-release morphine dose (to a maximum of 500 mg) on the evening of the titration. The total titration-day MOS and 12-hour extended-release morphine were summed into the post-titration-day SROM dose, to a maximum of 1000 mg.

DISCUSSION

In the cases described, substantial reductions in unregulated fentanyl use and social gains, such as obtaining housing, employment, and enrollment in inpatient treatment programs, were observed after rapid SROM titration. No overdoses occurred during rapid SROM titration or during SROM treatment. More research is needed to determine the role for rapid SROM titrations as a stabilization option for outpatients.

Awareness that cocaine can contain fentanyl among nightclub and festival attendees in New York City, 2018-2022

People who attend nightclubs and dance festivals-particularly those that feature electronic dance music (EDM), are at high risk for use of cocaine and other party drugs. Given that cocaine is now sometimes adulterated with fentanyl, this study examines trends in people's knowledge about such risk of adulteration to inform prevention and harm reduction efforts. Adults were surveyed entering randomly selected EDM events (including dance festivals) in New York City in 2018, 2019, 2021, and 2022 (n = 2107). They were asked whether they agree that some dealers sell cocaine containing fentanyl, and trends in agreement were estimated. Prevalence of agreement that cocaine can be adulterated increased from 42.1% (95% CI: 36.8-47.6) in 2018 to 65.6% (95% CI: 54.1-75.4) in 2022-a 55.8% increase (p < .001). Between 2018 and 2022, particular increases occurred among those not reporting past-year cocaine use (by 61.6%, p < .001), among White individuals (by 68.1%, p < .001), those with some college (by 68.5%, p = .021), and those age ≥26 (by 83.8%, p = .001). Awareness that cocaine can contain fentanyl is increasing in this high-risk population. Continued education is needed for high-risk populations regarding both opioid overdose response and test strips that can test drugs for the presence of fentanyl.

Experiences of violence during the COVID-19 pandemic among people who use drugs in a Canadian setting: a gender-based cross-sectional study

OBJECTIVES

People who use drugs (PWUD) experience disproportionately high rates of violent victimization. Emerging research has demonstrated that the COVID-19 pandemic has exacerbated violence against some priority populations (e.g., women), however there is limited research examining the impact of the pandemic on the experiences of violence of PWUD.

METHODS

Using data collected between July and November 2020 from three prospective cohort studies of PWUD in Vancouver, Canada, we employed multivariable logistic regression stratified by gender to identify factors associated with recent experiences of violence, including the receipt of COVID-19 emergency income support.

RESULTS

In total, 77 (17.3%) of 446 men, and 54 (18.8%) of 288 women experienced violence in the previous six months. Further, 33% of men and 48% of women who experienced violence reported that their experience of violence was intensified since the COVID-19 pandemic began. In the multivariable analyses, sex work (Adjusted Odds Ratio [AOR] = 2.15, 95% confidence interval [CI]: 1.06-4.35) and moderate to severe anxiety or depression (AOR = 3.00, 95% CI: 1.37-6.57) were associated with experiencing violence among women. Among men, drug dealing (AOR = 1.93, 95%CI: 1.10-3.38), street-based income sources (AOR = 1.93, 95%CI: 1.10-3.38), homelessness (AOR = 2.54, 95%CI: 1.40-4.62), and regular employment (AOR = 2.97, 95% CI: 1.75-5.04) were associated with experiencing violence.

CONCLUSION

Our study results suggest economic conditions and gender were major factors associated with experiencing violence among our sample of PWUD during COVID-19. These findings highlight criminalization of drug use and widespread socioeconomic challenges as barriers to addressing violence among PWUD during periods of crisis.

Safer opioid supply: qualitative program evaluation

BACKGROUND

As the overdose crisis in Canada continues to escalate in severity, novel interventions and programs are required. Safer Supply programs offer pharmaceutical-grade medication to people who use drugs to replace and decrease harms related to the toxic illicit drug supply. Given the paucity of research surrounding these programs, we sought to better understand the experience of being part of a Safer Supply program from the perspective of current participants.

METHODS

We completed semi-structured interviews and surveys with Safer Supply participants in Ottawa, Canada. Interviews were audio-recorded, transcribed, and analyzed thematically. Descriptive statistics were used to report survey data.

RESULTS

Participants most commonly discussed Safer Supply benefits. This included programs offering a sense of community, connection, hope for the future, and increased autonomy. Participants also described program concerns, such as restrictive protocols, inadequate drugs, and diversion.

CONCLUSIONS

Our research demonstrated that participants found Safer Supply to be effective and impactful for their substance use goals. While participants did discuss concerns about the program, overall, we found that this is an important harm reduction-based program for people who use drugs in the midst of the overdose crisis.

Stimulant use among patients in opioid treatment settings: Provider perspectives

INTRODUCTION

Methadone maintenance therapy (MMT) has been a pillar of opioid addiction treatment. Opioid treatment programs (OTPs) have been faced with an escalating threat of stimulant use and related overdose deaths among patients. We know little about how providers currently address stimulant use while maintaining treatment for opioid use disorder.

METHODS

We conducted 5 focus groups with 36 providers (n = 11 prescribers; 25 behavioral health staff), and collected an additional 46 surveys (n = 7 prescribers; 12 administrators; 27 behavioral health staff). Questions focused on perceptions of patient stimulant use and interventions. We applied inductive analysis to identify themes relevant to identification of stimulant use, use trends, intervention approaches, and perceived needs to improve care.

RESULTS

Providers indicated a trend of rising stimulant use among patients, especially those experiencing homelessness or comorbid health conditions. They reported a range of approaches to patient screening and intervention, including medication and harm reduction, improving treatment engagement, increasing level of care, and providing incentives. Providers expressed less agreement as to which of these interventions were effective, and though providers saw stimulant use as a common and severe problem, they reported little problem recognition and interest in treatment from their patients. A particular concern of providers was the prevalence and danger of synthetic opioids, such as fentanyl. They sought more research and resources to identify effective interventions and medications to address these issues. Also notable was an interest in contingency management (CM) and use of reinforcements/rewards to encourage stimulant use reduction.

CONCLUSION

Providers face challenges in treating patients who use both opioids and stimulants. Although methadone is available to treat opioid use, no such "silver bullet" exists for stimulant use disorder. The rise in stimulant and synthetic opioid (e.g., fentanyl) combination products is presenting an extraordinary challenge for providers whose patients are at unprecedented risk for overdose. Providing OTPs with more resources to address polysubstance use is critical. Existing research indicates strong support for CM in OTPs, but providers reported regulatory and financial barriers to implementation. Further research should develop effective interventions that are accessible to providers in OTPs.

Characteristics and correlates of fentanyl preferences among people with opioid use disorder

OBJECTIVES

Fentanyl has come to dominate the U.S. illicit opioid supply. We aimed to characterize and examine correlates of preferences for fentanyl vs. other opioids among individuals starting OUD treatment.

METHODS

We interviewed 250 adults initiating buprenorphine treatment with positive fentanyl toxicology at intake. We characterized opioid preferences and examined bivariate associations between opioid preference (preference for heroin, fentanyl, heroin-fentanyl mix, or other opioid) and sociodemographic characteristics, psychosocial factors, and substance use behaviors. We then used multinomial logistic regression to examine factors independently associated with fentanyl preferences.

RESULTS

Over half (52.0 %) of participants preferred fentanyl (21.2 % fentanyl alone, 30.8 % heroin-fentanyl mix). In bivariate comparisons, participants who preferred fentanyl were a higher acuity group with respect to risks and problems in general. In the multinomial logistic regression, people who preferred fentanyl, either alone or mixed with heroin, used non-prescribed buprenorphine less in the 30 days preceding treatment entry compared to people who preferred heroin or other opioids (RRRalone= 0.88 [0.78, 0.99]; P = 0.037 and RRRmixed= 0.91 [0.84, 0.99]; P = 0.046). People who preferred fentanyl alone were also younger (RRR= 0.93 [0.90, 0.97]; P < 0.001) and more likely to have severe mental illness (RRR= 2.5 [1.1, 5.6]; P = 0.027) than people who prefer heroin or other opioids.

CONCLUSIONS

Many people with OUD report preferring fentanyl. People who express preference for fentanyl differ substantively from those with other opioid preferences, and may be at elevated risk for poor health outcomes. Understanding preferences surrounding fentanyl could inform treatment and harm reduction interventions.

Trends and distinct profiles of persons who inject drugs in the United States, 2015-2019

Drug injection represents a major health problem in the US, with severe health consequences including the transmission of blood-borne infections. An examination of the most recent trends in drug injection is warranted by the fast-evolving drug epidemic and recent policy changes such as the federal funding ban on needle exchange programs. This research examines current drug injection trends, patterns, and socioeconomic and behavioral profiles of people who inject drugs (PWID). Data were derived from the 2002 to 2019 National Survey on Drug Use and Health (NSDUH). After examining the annual prevalence of drug injection since 2002, a latent class analysis was conducted to identify drug injection and other substance misuse patterns among PWID using the latest (2015-2019) NSDUH datasets. Associations between class membership and behavioral health comorbidities and treatment receipt were also assessed. The drug injection prevalence among US adults aged 18-64 increased from 0.21% in 2002/2004 to 0.36% in 2017/2019. Three distinctive groups were identified: the heroin injection group (45.2%), the methamphetamine injection group (28.0%), and the multi-drug injection group (26.8%). The methamphetamine injection group reported greater risks of experiencing serious psychological distress, suicidality, and limited substance use treatment. Special attention is needed for those who primarily injected methamphetamine. Programs to promote harm reduction and increase access to addiction treatment need to be expanded in at-risk communities while accounting for their distinct socioeconomic and drug use/misuse profiles.

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.

Infrequent detection of unintentional fentanyl use via urinalysis among people who regularly inject opioids in Sydney and Melbourne, Australia

BACKGROUND AND AIM

The current phase of the North American 'opioid crisis' is characterised by illicit fentanyl use; however, the presence of illicit fentanyl in Australia is unknown. This study aimed to monitor unintentional fentanyl consumption in Australia.

DESIGN

Rapid urine drug screens (UDS) paired with surveys conducted within supervised injecting facilities (SIFs) and confirmatory laboratory testing.

SETTING

Sydney and Melbourne, Australia.

PARTICIPANTS

Clients who used heroin within the past 2 days (n = 911 tests, 2017-2021). Participants were demographically similar to the overall client base (median age 43, 72% male).

MEASUREMENTS

UDS were conducted using BTNX Rapid Response fentanyl urine strip tests with cross-reactivity to numerous fentanyl analogues. Positive urine samples were analysed using liquid chromatography coupled with tandem mass spectrometry. Surveys covered past 3 day drug use and lifetime report of fentanyl in heroin.

FINDINGS

Two percent of participants reported intentional use of fentanyl, mostly through fentanyl patches. Of the 911 rapid UDS conducted, 17 (1.9%) yielded positive results. Eight of these (all from Melbourne) were not explained by survey-reported fentanyl use in the past 3 days. Of these 8 unexplained positives, confirmatory laboratory analysis was conducted on 6, with 4 deemed to be false positives, and 2 confirmed for the presence of fentanyl. This represents the first confirmation of unintended use of fentanyl type substances in this population.

CONCLUSION

There is limited evidence of unintentional fentanyl use among people in Sydney and Melbourne, Australia who regularly inject heroin, suggesting that, currently, there is very little illicit fentanyl in Australian drug markets accessed by supervised injecting facilities attendees. This study demonstrates the feasibility of quick onsite testing to cost-effectively screen large samples for fentanyl; however, the high false positive rate emphasises the need for confirmation of positive tests through advanced analytical techniques.

Violence, policing, and systemic racism as structural barriers to substance use treatment amongst women sex workers who use drugs: Findings of a community-based cohort in Vancouver, Canada (2010-2019)

BACKGROUND

Despite a high prevalence of substance use among women sex workers (SWs), rigorous social epidemiologic data on substance use treatment experiences among SWs remains limited. Given these gaps and the disproportionate burden of criminalization borne by Indigenous SWs, we evaluated (1) structural correlates of unsuccessful attempts to access substance use treatment; and (2) the interaction between policing and Indigenous ancestry on unsuccessful attempts to access treatment among SWs who use drugs.

METHODS

Prospective data were from an open community-based cohort of women SWs (2010-2019) in Vancouver, Canada. Bivariate and multivariable logistic regression with generalized estimating equations(GEE) assessed correlates of unsuccessful attempts to access treatment. A multivariable GEE confounder model examined the interaction between Indigenous ancestry and policing on unsuccessful attempts to access treatment.

RESULTS

Amongst 645 SWs who used drugs, 32.1 % reported unsuccessful attempts to access substance use treatment during the 9.5-year study. In multivariable GEE analysis, unsuccessful substance use treatment access was associated with identifying as a sexual/gender minority (AOR: 1.90, 95 %CI:1.37-2.63), opioid use (AOR: 1.43, 95 %CI: 1.07-1.91), and exposure to homelessness (AOR: 1.72; 95 %CI:1.33-2.21), police harassment (AOR: 1.48, 95 %CI:1.03-2.13), workplace violence (AOR: 1.80, 95 %CI: 1.31-2.49) and intimate partner violence (AOR: 2.11, 95 %CI:1.50-2.97). In interaction analysis, Indigenous SWs who experienced police harassment faced the highest odds of unsuccessful attempts to access substance use treatment (AOR: 2.59, 95 %CI:1.65-4.05).

CONCLUSION

Findings suggest a need to scale-up culturally-safe, trauma-informed addictions, gender-based violence, and sex worker services, alongside dismantling of systemic racism across and beyond health and addictions services.

Preclinical Efficacy and Selectivity of Vaccines Targeting Fentanyl, Alfentanil, Sufentanil, and Acetylfentanyl in Rats

The ongoing public health emergency of opioid use disorders (OUD) and overdose in the United States is largely driven by fentanyl and its related analogues and has resulted in over 75 673 deaths in 2021. Immunotherapeutics such as vaccines have been investigated as a potential interventional strategy complementary to current pharmacotherapies to reduce the incidence of OUD and opioid-related overdose. Given the importance of targeting structurally distinct fentanyl analogues, this study compared a previously established lead conjugate vaccine (F₁-CRM) to a series of novel vaccines incorporating haptens derived from alfentanil and acetylfentanyl (F_{8, 9a, 9b, 10}), and evaluated their efficacy against drug-induced pharmacological effects in rats. While no vaccine tested provided significant protection against alfentanil, lead formulations were effective in reducing antinociception, respiratory depression, and bradycardia elicited by fentanyl, sufentanil, and acetylfentanyl. Compared with control, vaccination with F₁-CRM also reduced drug levels in the brain of rats challenged with lethal doses of fentanyl. These data further support investigation of F₁-CRM as a candidate vaccine against fentanyl and selected analogues.

Pharmacological Profiling of Antifentanyl Monoclonal Antibodies in Combination with Naloxone in Pre- and Postexposure Models of Fentanyl Toxicity

The incidence of fatal drug overdoses in the United States is an alarming public health threat that has been exacerbated by the COVID-19 pandemic, resulting in over 100,000 deaths between April 2020 and April 2021. A significant portion of this is attributable to widespread access to fentanyl and other synthetic opioids, alone or in combination with heroin or psychostimulants, such as cocaine or methamphetamine. Monoclonal antibodies (mAb) offer prophylactic and therapeutic interventions against opioid overdose by binding opioids in serum, reducing distribution of drug to the brain and other organs. Here, we investigated the efficacy of a leading antifentanyl mAb, clone HY6-F9, in reversal and prevention of fentanyl-induced toxicity compared with the opioid receptor antagonist naloxone (NLX) in rats. In postexposure models, rats were challenged with fentanyl, followed by HY6-F9, NLX, or both. HY6-F9 reversed fentanyl-induced antinociception, respiratory depression, and bradycardia, and rats retained protection against additional challenges for at least 1 week. Although intravenous NLX reversed fentanyl-induced respiratory depression more rapidly than mAb alone, kinetics of reversal by intravenous mAb were similar to subcutaneous NLX. Coadministration of mAb and NLX provided greater protection than individual treatments against high doses of fentanyl. Prophylactic administration of mAb reduced the ED50 of NLX approximately twofold against 2.25 mg/kg of fentanyl. Finally, mAb sequestered fentanyl and its metabolite norfentanyl in serum and reduced brain concentrations of fentanyl. These results support the translation of mAb as medical interventions alone or in combination with NLX to prevent and reverse fentanyl-related overdose. SIGNIFICANCE STATEMENT: Fentanyl-related overdoses have increased dramatically in the US and worldwide. Currently, approved pharmacotherapies for treatment of opioid use disorder and reversal of overdose are not sufficient to curb the incidence of opioid-related deaths. Additionally, fentanyl and its potent analogs present a potential risk from use in deliberate poisoning or chemical attacks. This study demonstrates the use of monoclonal antibodies as a countermeasure to fentanyl-induced toxicity in pre- and postexposure scenarios, supporting their use in combination with the opioid antagonist naloxone.

Social-Structural Predictors of Fentanyl Exposure among Street Involved Youth

ObjectiveThe emergence of synthetic fentanyl has been a main contributor to North America's rising overdose death rates. While increasing attention has been given to drug-related harm among youth, little is known about how social-structural conditions influence their risk of fentanyl exposure. Therefore, we evaluated potential relationships between social-structural conditions and fentanyl exposure among youth who use illicit drugs in Vancouver, BC. Methods: Data were derived from the At-Risk Youth Study (ARYS), a prospective cohort study. The ARYS cohort involves street-involved youth, who use illicit substances in Vancouver, Canada. A multivariable logic regression analysis model was used to identify social factors associated with recent fentanyl exposure as determined through urine drug screening. Results: Overall, 423 participants were included in this analysis, with 380 (38.23%) testing positive for recent fentanyl exposure. In a multivariable relative risk analysis, living in Vancouver's Downtown Eastside in the last six months (RR = 1.16, 95% CI: 1.03-1.32) and daily heroin injection drug use (RR = 1.31, 95% CI: 1.15 - 1.50) were positively associated with fentanyl exposure. As a secondary measure, we found that within the encounters who denied using fentanyl (92.25% of total encounters), 321 (35.05%) still tested positive. Conclusions: We found that youth residing in Vancouver's Downtown Eastside was positively associated with being exposed to fentanyl. Our findings highlight the need to support youth in finding secure housing outside of Vancouver's drug use epicenter to reduce fentanyl exposure.

Inability to contact opioid agonist therapy prescribers during the COVID-19 pandemic in a Canadian setting: a cross-sectional analysis among people on opioid agonist therapy

BACKGROUND

The COVID-19 pandemic and consequent public health response may have undermined key responses to the protracted drug poisoning crisis, including reduced access to opioid agonist therapy (OAT) among people with opioid use disorder. Our study objectives were to estimate the prevalence of and identify factors associated with inability to contact OAT prescribers when in need among people on OAT in a Canadian setting during the dual public health crises.

METHODS

Survey data were collected from three prospective cohort studies of community-recruited people who use drugs between July and November 2020, in Vancouver, Canada. A multivariable logistic regression analysis was used to identify potential factors associated with inability to contact OAT prescribers among patients who accessed OAT in the past 6 months.

RESULTS

Among 448 respondents who reported accessing OAT in the past 6 months, including 231 (54.9%) men, 85 (19.0%) reported having been unable to contact OAT prescribers when needed, whereas 268 (59.8%) reported being able to talk to their prescriber when needed, and 95 (21.2%) reported that they did not want to talk to their medication prescriber in the previous 6 months. Among those who reported inability to contact prescribers, 45 (53.6%) reported that their overall ability to contact prescribers decreased since the start of the pandemic. In multivariable analyses, factors independently associated with inability to talk to OAT prescribers included: chronic pain (Adjusted Odds Ratio [AOR] = 1.82; 95% Confidence Interval [CI] 1.02, 3.27), moderate to severe symptoms of depression or anxiety (AOR = 4.74; 95% CI 2.30, 9.76), inability to access health/social services (AOR = 2.66; 95% CI 1.41, 5.02), and inability to self-isolate or socially distance most or all of the time (AOR = 2.13; 95% CI 1.10, 4.14).

CONCLUSIONS

Overall, approximately one fifth of the sample reported inability to contact their OAT prescribers when needed, and those people were more likely to have co-occurring vulnerabilities (i.e., co-morbidities, inability to access health/social services) and higher vulnerability to COVID-19. Interventions are needed to ensure optimal access to OAT and mitigate the deepening health inequities resulting from the COVID-19 pandemic and the escalating drug poisoning crisis.

Increasing preference for fentanyl among a cohort of people who use opioids in Vancouver, Canada, 2017-2018

Background: Despite increasing prevalence of illicit fentanyl use in the US and Canada, preference for fentanyl over other illicit opioids has not been fully characterized. Therefore, we sought to describe changes in illicit opioid preferences over time among people who inject drugs (PWID). Methods: Data were obtained from two prospective cohort studies between 2017 and 2018. Trends in opioid preference over time were examined using bivariable generalized estimating equation (GEE) analysis. Multivariable models were used to identify factors associated with fentanyl preference. Results: Among 732 eligible participants, including 425 (58%) males, the prevalence of preference for fentanyl increased from 4.4% in 2017 to 6.6% in 2018 (Odds Ratio [OR] = 1.27, 95% Confidence Interval [CI]: 1.05-1.52). In a multivariable analysis, younger age (Adjusted Odds Ratio [AOR] = 0.94, 95% CI: 0.92-0.96) and daily crystal methamphetamine injection (AOR = 1.68, 95% CI: 1.01-2.78) were independently associated with preference for fentanyl. The most common reasons for preferring fentanyl included "better high than other opioids" (45%), and "lasts longer than heroin" (27%). Conclusions: The current study has demonstrated that preference for fentanyl has been increasing over time among our sample of PWID who use opioids. Further work is needed to clarify risk factors surrounding transitions to illicit fentanyl.

Prevalence and longitudinal correlates of recent exposure to fentanyl among HIV-positive people who use unregulated drugs during a community-wide overdose crisis

The United States and Canada are experiencing an opioid overdose crisis driven largely by exposure to fentanyl (a potent synthetic opioid), with little known about fentanyl exposure among HIV-positive people who use unregulated drugs (PWUD). We sought to estimate the prevalence and correlates of fentanyl exposure among a community-recruited sample derived from a prospective cohort study of HIV-positive PWUD in Vancouver, Canada. Generalized linear mixed-effects analyses were used to identify longitudinal factors associated with a fentanyl-positive urine drug screen test. Between June 2016-November 2017, 456 participants were recruited and contributed 1007 observations. At baseline, 96% of participants were ART-exposed, 72% had an HIV viral load (VL) <50 copies/mL and 21% had a fentanyl-positive test. Longitudinally, fentanyl-positive tests were characterized by: younger participant age (Adjusted Odds Ratio [AOR] = 0.45), recent non-fatal overdose (AOR = 2.30), engagement in opioid agonist therapy (AOR = 1.91), and at least daily heroin injection (AOR = 11.27). CD4+ cell count was negatively associated with fentanyl urine positivity (AOR = 0.92) (all p < 0.05). We identified several risk factors for overdose linked to fentanyl exposure among this sample, although no link with HIV treatment engagement or detectable HIV VL. Innovative strategies are needed to reduce the harmful effects of the contaminated unregulated drug supply experienced by PWUD.

Drugs of Abuse and Their Impact on Viral Pathogenesis

Commonly misused substances such as alcohol, cocaine, heroin, methamphetamine, and opioids suppress immune responses and may impact viral pathogenesis. In recent years, illicit use of opioids has fueled outbreaks of several viral pathogens, including the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). This review focuses on the myriad of mechanisms by which drugs of abuse impact viral replication and disease progression. Virus–drug interactions can accelerate viral disease progression and lead to increased risk of virus transmission.

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.

Retention in opioid agonist treatment: a rapid review and meta-analysis comparing observational studies and randomized controlled trials

BACKGROUND

Although oral opioid agonist therapies (OATs), buprenorphine and methadone, are effective first-line treatments, OAT remains largely underutilized due to low retention rates and wide variation across programs. This rapid review therefore sought to summarize the retention rates reported by randomized controlled trials (RCTs) and controlled observational study designs that compared methadone to buprenorphine (or buprenorphine-naloxone).

METHODS

We searched four electronic databases (EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, CINAHL, up to April 2018) for RCTs and controlled observational studies that compared oral fixed-dose methadone to buprenorphine versus methadone (or buprenorphine-naloxone). Data were extracted separately for two different definitions of retention in treatment: (1) length of time retained in the study and (2) presence on the final day of a study. Separate random effects meta-analyses were performed for RCTs and controlled observational studies. Data from controlled observational studies where retention was measured as the length of time retained in the study were not amenable to meta-analysis.

RESULTS

Among 7603 studies reviewed, 10 RCTs and 3 observational studies met inclusion criteria (n = 5065) and compared fixed-dose oral buprenorphine with methadone. Across studies, the average retention rate was highly variable (RCTs: buprenorphine 20.0-82.5% and methadone 30.7-83.8%; observational studies: buprenorphine 20.2-78.3% and methadone 48.3-74.8%). For time period retained in the study, we observed no significant difference in treatment retention for buprenorphine versus methadone in RCTs (standardized mean difference [SMD] =  - 0.07; 95% CI - 0.35-0.21, p = 0.63; quality of evidence: low). For presence on the final study day, we observed no significant difference between buprenorphine and methadone treatment retention in RCTs (risk ratio [RR] = 0.89; 95% CI 0.73-1.08, p = 0.24; quality of evidence: low) and controlled observational studies (RR = 0.75; 95% CI 0.36-1.58, p = 0.45).

CONCLUSION

Meta-analysis of existing RCTs suggests retention in oral fixed-dose opioid agonist therapy with methadone appears to be generally equal to buprenorphine (or buprenorphine-naloxone), with wide variation across studies. Similarly, a meta-analysis of three controlled observational studies indicated no difference in treatment retention although there was significant heterogeneity among the included studies. The length of follow-up did not appear to affect the retention rate.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018104452 .

Community overdose surveillance: Comparing substances collected from the death scene investigation to toxicology results

BACKGROUND

Recent overdose trends are characterized by increased toxicological detection of stimulants with opioids, yet it is unclear whether these substances are mixed prior to consumption or purposefully used simultaneously.

METHODS

Postmortem toxicology data were collected in Marion County, Indiana, from 45 fatal overdose cases involving heroin, fentanyl, methamphetamine, or cocaine. Substances found by death scene investigators at the scene of the fatal overdose (57 samples) were tested using high-pressure liquid chromatography mass-spectrometry (LC-MS) technology. We compared toxicology and LC-MS results to understand whether substances contributing to overdose were found in combination or separately at the scene of the overdose.

RESULTS

Comparing toxicology reports with LC-MS results from substances found at the scene of overdose deaths involving opioids and stimulants reveal that deaths are largely the result of the co-use of opioids and stimulants, rather than use of stimulants combined with opioids.

CONCLUSIONS

Collecting and testing physical samples from fatal overdose scenes and comparing these to post-mortem toxicology results is a new way to examine polydrug use patterns. This community overdose surveillance method can be used to improve overdose prevention and response efforts.

A modified two-process Knox test for investigating the relationship between law enforcement opioid seizures and overdoses

Recent research has shown an association between monthly law enforcement drug seizure events and accidental drug overdose deaths using cross-sectional data in a single state, whereby increased seizures correlated with more deaths. In this study, we conduct statistical analysis of street-level data on law enforcement drug seizures, along with street-level data on fatal and non-fatal overdose events, to determine possible micro-level causal associations between opioid-related drug seizures and overdoses. For this purpose, we introduce a novel, modified two-process Knox test that controls for self-excitation to measure clustering of overdoses nearby in space and time following law enforcement seizures. We observe a small, but statistically significant ( p  < 0.001), effect of 17.7 excess non-fatal overdoses per 1000 law enforcement seizures within three weeks and 250 m of a seizure. We discuss the potential causal mechanism for this association along with policy implications.

The perspectives of people who use drugs regarding short term involuntary substance use care for severe substance use disorders

BACKGROUND

In the Canadian Province of British Columbia (BC), the BC Mental Health Act permits involuntary care for treating mental disorders. However, the Act has also been applied to provide involuntary care to individuals with a primary substance use disorder, in the absence of specific guidelines and legislation, and with insufficient understanding of perspectives of people who use drugs (PWUD) regarding this approach.

METHODS

As part of a larger mixed-methods research project providing an overview of involuntary care for severe substance use disorders in BC, three focus groups were convened with: PWUD, families and caregivers, and Indigenous community stakeholders. This analysis examines perspectives from the focus group of PWUD, consisting of nine participants from local and regional drug user and advocacy organizations regarding involuntary care. A qualitative descriptive approach and thematic analysis were conducted, using a coding framework developed deductively and inductively, and participant perspectives were interpreted drawing on problematization theory.

RESULTS

Participants did not endorse the use of involuntary care, instead emphasizing significant changes were needed to address shortcomings of the wider voluntary care system. When asked to conceptualize what an acceptable involuntary care scenario might look like (under hypothetical and ideal conditions), participants recommended it should include: individual control and autonomy, peer advocacy in decision-making, and elimination of police and criminal justice system involvement from treatment encounters. Participants saw involuntary care to be an inappropriate approach given the shortcomings of the current system, noting also problems inherent in its use to manage severe SUDs and imminent harm, and prioritized alternate approaches to offsetting risks.

CONCLUSION

Improving voluntary care for substance use, along with addressing the social determinants of health that put individuals at risk of problematic substance use and harm, were prioritized in participant perspectives. Participant comments regarding the use of involuntary care bring forward alternate solutions in the context of the opioid overdose crisis, and a reconceptualization of the 'problem' of managing severe substance use disorders.

High-intensity cannabis use and hospitalization: a prospective cohort study of street-involved youth in Vancouver, Canada

BACKGROUND

There is concern that cannabis use negatively affects vulnerable groups such as youth; however, the relationship between cannabis use and health care utilization has not been well characterized in this population. We longitudinally evaluated the association between daily cannabis use and hospitalization among a prospective cohort of street-involved youth.

METHODS

Data were collected from the At-Risk Youth Study (ARYS) in Vancouver, Canada, from September 2005 to May 2015. Participants were interviewed semi-annually and multivariable generalized estimating equation (GEE) logistic regression was used to examine the relationship between daily cannabis use and hospitalization.

RESULTS

A total of 1216 participants (31.2% female) were included in this analysis, and 373 (30.7%) individuals reported hospitalization at some point during the study period. In a multivariable GEE analysis, daily cannabis use was not significantly associated with hospitalization (Adjusted Odds Ratio [AOR] = 1.17, 95% Confidence interval [CI] = 0.84, 1.65). We did observe a significant interaction between daily cannabis use and sex (AOR = 0.51, 95% CI = 0.34, 0.77), whereby cannabis use was associated with a decreased odds of hospitalization among males (AOR = 0.60, 95% CI = 0.47, 0.78), yet was not significantly associated with hospitalization among females (AOR = 1.19, 95% CI = 0.84, 1.67).

CONCLUSIONS

The finding that daily cannabis use was not associated with hospitalization among street-involved youth is encouraging given the high rates of cannabis use in this population and the expansion of cannabis legalization and regulation. Future studies, however, are warranted to monitor possible changes in the consequences of cannabis use as cannabis legalization and regulation increase internationally.

A gender comparative analysis of post-traumatic stress disorder among a community-based cohort of people who use drugs in Vancouver, Canada

BACKGROUND

While exposure to traumatic events and subsequent post-traumatic stress disorder (PTSD) are common among people who use drugs (PWUD), little is known about gender-based differences associated with PTSD in this population. We explore gender-based differences in factors associated with a probable PTSD diagnosis in a cohort of PWUD from Vancouver, Canada.

METHODS

Data were collected through the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS), two community-recruited cohorts of PWUD. Participants were administered the PTSD Checklist for DSM-5. Multivariable logistic regression was used to investigate social-structural factors and substance use patterns and behaviours associated with a probable PTSD diagnosis, stratified by self-identified gender. PTSD symptom clusters and brief descriptions of the worst traumatic event experienced were also reported.

RESULTS

Between December 2016 and December 2018, of 797 eligible participants, 295 (37.0%) identified as women. PTSD was more commonly reported in women compared to men (53.2% vs. 31.5%, p < 0.001). In multivariable analysis involving men, no correlates were associated with PTSD. In multivariable analysis involving women, PTSD was positively associated with exposure to violence (AOR: 3.66; 95%CI: 1.14-11.72), daily stimulant use (AOR: 2.32; 95%CI: 1.32-4.08) and heavy alcohol use (AOR: 3.84; 95%CI: 1.84-8.00), and negatively associated with being in a stable relationship (AOR: 0.46; 95%CI: 0.25-0.84).

CONCLUSIONS

Gender-based differences in PTSD diagnosis among a cohort of PWUD point to the need to develop gender-focused and trauma-informed health and social services to meet the immediate needs of PWUD living with PTSD.

'Resurgent', 'twin' or 'silent' epidemic? A select data overview and observations on increasing psycho-stimulant use and harms in North America

In the early 2000s, increasing prevalence of psycho-stimulant (e.g., crack/cocaine, methamphetamine) use and related harms, including severe adverse health outcomes, was observed among - mostly marginalized - populations of persons using illicit drugs in North America, underscoring an urgent need for interventions options towards improved prevention and treatment. By about 2010, however, the 'opioid crisis', featuring unprecedented use and public health burden, had accelerated into full force in North America, largely muting attention to the psycho-stimulant issue until recently. Recent surveillance data on drug use and related mortality/morbidity from the present decade has documented a marked resurgence of psycho-stimulant use and harms especially in at-risk populations, commonly in direct combination with opioids, across North America, resulting in a 'twin epidemic' comprised of opioids and psycho-stimulants We briefly review select epidemiological data indicators for these developments from the United States and Canada; in the latter jurisdiction, related evidence has been less prevalent and systematic but corroborating the same trends. Evidently, the (widely ongoing) focus on the 'opioid epidemic' as a 'mono-type' drug problem has become an anachronism that requires urgent and appropriate correction. We then briefly consider existing, evidence-based options for - prevention and treatment - interventions targeting psycho-stimulant use and harms, which are substantially more limited and/or less efficacious than those available for problematic opioid use, while presenting major gaps and challenges. The observed resurgence of psycho-stimulants may, indirectly, relate to recent efforts towards curtailing (medical) opioid availability, thereby accelerating demand and supply for both illicit opioids and psycho-stimulants. The presently unfolding 'twin epidemic' of opioids and psycho-stimulants, combined with limited intervention resources, presents an acute challenge for public health and may crucially undermine actively extensive efforts to reduce opioid-related health harms in North America.

Rise in Presence of Methamphetamine in Oral Fluid Toxicology Tests Among Outpatients in a Large Healthcare Setting in the Northeast

OBJECTIVES

To examine changes in presence of methamphetamine in toxicology testing among outpatients receiving healthcare in Boston, Massachusetts.

METHODS

A serial cross-sectional study of oral fluid drug test results over a 6-year period of all patient specimens submitted for testing as part of routine care across an academic medical center in Boston, Massachusetts and affiliated primary care practices which has roughly 48,000 admissions and 500,000 primary care visits per year. All samples were subjected to definitive drug testing by liquid chromatography-tandem mass spectrometry for fentanyl, 6-monoacetylmorphine (6-MAM, metabolite of heroin), benzoylecgonine (metabolite of cocaine), cocaine, and methamphetamine. We compared positive rates and change over time across the same calendar months (February to July) of 6 consecutive years from 2014 to 2019.

RESULTS

Total of 17,303 oral fluid samples collected from outpatients receiving routine healthcare across 6 years were analyzed. Samples showing presence of methamphetamine, cocaine, and fentanyl increased over the study period, whereas 6-MAM presence decreased. From 2014 to 2019 samples with methamphetamine present increased from 0.9% to 5.1% and samples with 6-MAM present decreased from 9.5% to 2.8%. Fentanyl was added to the testing panel in 2017. In 2019, 15.7% of samples had fentanyl present. Polysubstance use was common; 44% of samples with methamphetamine also showed cocaine or benzoylecgonine, 25% showed fentanyl, and 3% showed 6-MAM presence.

CONCLUSIONS

Presence of methamphetamine in oral fluid toxicology tests increased from 2014 to 2019 across a sample of outpatients receiving healthcare in Boston, Massachusetts. Regions of the country with high rates of opioid overdose may need to integrate harm reduction and addiction treatment resources for stimulant use disorder in addition to opioid use disorder.

Factors associated with drug checking service utilization among people who use drugs in a Canadian setting

BACKGROUND

The United States and Canada are amidst an opioid overdose crisis, with the Canadian province of British Columbia (BC) among the hardest hit. In response, drug checking services (DCS) have been introduced in this setting as a novel pilot harm reduction intervention though little is known about usage rates. Therefore, we sought to identify factors associated with drug checking uptake among people who use drugs (PWUD) in Vancouver, BC.

METHODS

Data were derived from three ongoing prospective cohort studies of PWUD in Vancouver between June and November 2018. Multivariable logistic regression was used to determine factors associated with self-reported DCS utilization in the past 6 months among participants at high risk of fentanyl exposure (i.e., those self-reporting illicit opioid use or testing positive for fentanyl via urine drug screen).

RESULTS

Among 828 eligible participants, including 451 (55%) males, 176 (21%) reported recent use of DCS. In multivariable analyses, factors significantly associated with DCS utilization included: homelessness (Adjusted Odds Ratio [AOR] 1.47; 95% Confidence Interval [CI] 1.01-2.13) and involvement in drug dealing (AOR 1.59; 95% CI 1.05-2.39).

CONCLUSIONS

In our sample of PWUD, uptake of DCS was low, although those who were homeless, a sub-population known to be at a heightened risk of overdose, were more likely to use the services. Those involved in drug dealing were also more likely to use the services, which may imply potential for improving drug market safety. Further evaluation of drug checking is warranted.

High prevalence of unmet healthcare need among people who use illicit drugs in a Canadian setting with publicly-funded interdisciplinary primary care clinics

BACKGROUND

People who use illicit drugs (PWUD) experience significant barriers to healthcare. However, little is known about levels of attachment to primary care (defined as having a regular family doctor or clinic they feel comfortable with) and its association with unmet healthcare needs in this population. In a Canadian setting that features novel publicly-funded interdisciplinary primary care clinics, we sought to examine the prevalence and correlates (including attachment to primary care) of unmet healthcare needs among PWUD. Methods: Data were derived from two prospective cohort studies of PWUD in Vancouver, Canada between December 2017 and November 2018. Multivariable logistic regression was used to identify factors associated with self-reported unmet healthcare needs among participants reporting any health issues. Results: In total, 743 (83.6%) of 889 eligible participants reported attachment to primary care and 220 (24.7%) reported an unmet healthcare need. In multivariable analyses, attachment to primary care at an integrated care clinic (adjusted odds ratio [AOR] = 0.14; 95% Confidence Interval [CI]: 0.06-0.34) was negatively associated with an unmet healthcare need, while being treated poorly at a healthcare facility (AOR = 5.50; 95% CI: 3.59-8.60) and self-reported chronic pain (AOR = 2.00, 95% CI: 1.30-3.01) were positively associated with an unmet healthcare need. Conclusion: Despite the high level of attachment to primary care, a quarter of our sample reported an unmet healthcare need. Our findings suggest that multi-level interventions are required to address the unmet need, including pain management and integrated care, to support PWUD with complex health needs.

Understanding concurrent stimulant use among people on methadone: A qualitative study

INTRODUCTION AND AIMS

Opioid-related overdoses are an epidemic in North America, prompting a greater use of medications for opioid use disorder, such as methadone. Although many people work toward overall drug abstinence while on methadone, a sub-population of people with and without histories of polysubstance use engage in stimulant use while on methadone treatment. This study explores motivations for concurrent stimulant and methadone use in a street-involved drug-using population.

DESIGN AND METHODS

Semi-structured qualitative interviews were conducted with 39 people on methadone in Vancouver, Canada. Participants were recruited from among the participants in two community-based prospective cohort studies consisting of HIV-positive and HIV-negative people who use drugs. Interview transcripts were analysed using an inductive and iterative approach.

RESULTS

Our analysis identified three primary themes. First, participants articulated how stimulants were used to counter the sedating effects of methadone and enable them to engage in daily and survival activities (e.g. income generation). Second, participants described increased stimulant use to compensate for reduced stimulant intoxication while taking methadone. Finally, participants described the desire to achieve intoxication on stimulants once stable on methadone, as their substance use treatment goals did not involve drug abstinence.

DISCUSSION AND CONCLUSION

Among a street-involved drug-using population in which people do not have abstinence-based treatment goals, there are several functional reasons to use stimulants concurrently while on methadone. A deeper and more nuanced understanding of substance use motivators may contribute to further research and inform policy and guideline changes that support low threshold and harm reduction-focused methadone treatment programs and other interventions to reduce drug-related harms.

Characterization of HCV-infected people who inject drugs (PWID) in the setting of clinical care in Canada (CAPICA): A retrospective study

BACKGROUND: People who use drugs (PWUD) are among the highest risk category for becoming infected with the hepatitis C virus (HCV) in Canada. There is a need for more information on the demographics of HCV-infected PWUD/PWID who have recently injected drugs or who are actively injecting drugs. METHODS: CAPICA was a multicentre, retrospective database/chart review conducted from October 2015 to February 2016 that was designed to characterize HCV-infected people who inject drugs (PWID) and are enrolled in clinical care in Canada. The aim was to identify factors of health care engagement essential in the design systems of HCV care and treatment in this population. The study enrolled 420 patients with a history of injection drug use within the last 12 months who had been diagnosed with chronic viremic HCV infection and had been participants in an outpatient clinical care setting in the past 12 months. Patients who were co-infected with HIV/HCV were excluded. RESULTS: Harm reduction programs were in place at 92% (11/12) of the sites, and 75% (9) of these sites offered opioid agonist therapy (OAT), with 48% of the patients currently taking OAT. HCV genotype 1a was most prevalent (56%), followed by G3 (34%), and the most common fibrosis score was F1 (34%). The average reinfection rate was about 5%. Seventeen percent of the patients were undergoing HCV treatment or had recently failed therapy, while 83% were not being treated. CONCLUSIONS: In a multivariate analysis, the following factors were significantly associated with treatment: increasing age (OR 1.10), a fibrosis score of F4 (OR 4.91), moderate alcohol consumption (OR 3.70), and not using a needle exchange program (OR 6.95).

Frequent Cannabis Use Is Negatively Associated with Frequency of Injection Drug Use Among People Who Inject Drugs in a Canadian Setting

Objectives: High levels of morbidity and mortality associated with injection drug use continue to represent a significant public health challenge in many settings worldwide. Previous studies have shown an association between cannabis use and decreased risk of some drug-related harms. We sought to evaluate the association between high-intensity cannabis use and the frequency of injection drug use among people who inject drugs (PWID). Methods: The data for this analysis were collected from three prospective cohorts of PWID in Vancouver, Canada, between September 2005 and May 2018. Generalized linear mixed-effects models were used to analyze the association between daily cannabis use and the frequency of injecting illegal drugs (i.e., self-reported average number of injections per month). Results: Among the 2,619 active PWID, the frequency of injection drug use was significantly lower among people who use cannabis daily compared with people who use it less than daily (adjusted odds ratio [AOR]=0.84, 95% confidence interval [CI]: 0.73-0.95). Sub-analyses indicated that this effect was restricted to the frequency of illegal opioid injection (AOR=0.78, 95% CI: 0.68-0.90); the association between daily cannabis use and the frequency of illegal stimulant injection was not significant (AOR=1.08, 95% CI 0.93-1.25). Discussion: The findings from these prospective cohorts suggest that people who use cannabis daily were less likely to report daily injection of illegal drugs compared with people who use it less than daily. These results suggest the potential value of conducting experimental research to test whether controlled administration of cannabinoids impacts the frequency of illegal opioid injection among PWID.

Endogenous Opiates and Behavior: 2018

This paper is the forty-first consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2018 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 (2), the roles of these opioid peptides and receptors in pain and analgesia in animals (3) and humans (4), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (5), opioid peptide and receptor involvement in tolerance and dependence (6), stress and social status (7), learning and memory (8), eating and drinking (9), drug abuse and alcohol (10), sexual activity and hormones, pregnancy, development and endocrinology (11), mental illness and mood (12), seizures and neurologic disorders (13), electrical-related activity and neurophysiology (14), general activity and locomotion (15), gastrointestinal, renal and hepatic functions (16), cardiovascular responses (17), respiration and thermoregulation (18), and immunological responses (19).

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.

Elevated prevalence of self-reported unintentional exposure to fentanyl among women who use drugs in a Canadian setting: A cross-sectional analysis

BACKGROUND

The United States and Canada are in the midst of an overdose epidemic, fueled by illicitly manufactured fentanyl. While marked differences in vulnerability to drug-related harm between men and women who use drugs is well characterized, the extent to which gender differences manifest in the present overdose crisis remains understudied. We examined differences in self-reported unintentional exposure to fentanyl between men and women who use drugs.

METHODOLOGY

Data were derived from three prospective cohorts of people who use drugs in Vancouver, Canada. Survey data were extracted on individuals who self-reported having used drugs known or believed to contain fentanyl in the past 30 days between December 2016 and November 2017. We used multivariable logistic regression (MLR) to examine the relationship between self-identified gender (woman vs. man) and self-reported unintentional exposure to fentanyl. As a sub-analysis, correlates of self-reported unintentional exposure to fentanyl were identified using MLR, stratified by gender.

RESULTS

Of 578 eligible participants, including 219 (37.9%) women, 200 (33.2%) perceived their exposure to fentanyl as unintentional (40.2% among women and 29.0% among men). In the MLR, being a woman was positively associated with self-reported unintentional fentanyl exposure (adjusted odds ratio = 2.11; 95% confidence interval: 1.45-3.09). Among women at least daily heroin use was negatively associated with self-reported unintentional fentanyl exposure, while perceiving a high or moderate risk of overdosing on fentanyl was positively associated with outcome. Among men older age was positively associated with self-reported unintentional fentanyl exposure, while injection drug use and at least daily heroin use was negatively associated with the outcome (all p<0.05).

CONCLUSIONS

Women were more than two times as likely to self-report they were unintentionally exposed to fentanyl compared to men. These findings highlight the urgent need to further understand experiences of gender-based risk differences and develop gender-focused interventions and policies aimed at preventing drug-related harm.

Changes in drug use behaviors coinciding with the emergence of illicit fentanyl among people who use drugs in Vancouver, Canada

Background: With the emergence of illicitly-manufactured fentanyl, drug overdose deaths have risen in unprecedented numbers. In this context, there is an urgent need to characterize potential changes in drug use behaviors among people who use drugs (PWUD). Objective: To examine changes in drug use behaviors following the emergence of illicit fentanyl among people who use drugs (PWUD). Methods: Data for this cross-sectional analysis was derived from three prospective cohorts of PWUD between December 2016 and May 2017 in Vancouver, Canada. Multivariable logistic regression was used to determine factors associated with self-reported behavior changes (binary variable "yes" or "no") following the emergence of illicit fentanyl. Results: Among 999 participants [363 (36.3%) females], 388 (38.8%) reported some behavior change. The remaining 611 (61.2%) reported no change in behavior; 240 (39.3%) of these individuals had recently been exposed to fentanyl. In multivariable analyses, factors independently associated with behavior change included recent non-fatal overdose (Adjusted Odds Ratio [AOR] = 2.28), active injection drug use (AOR = 1.96), being on opioid agonist therapy (AOR = 1.80), and urine drug screen positive for fentanyl (AOR = 1.45), (all p < .05). Conclusion: The majority of PWUD in our sample did not change their drug use behavior despite a high prevalence of fentanyl exposure, indicating a need for targeted behavior change messaging and overdose prevention efforts such as naloxone and addiction treatment for this sub-population of PWUD. Further, the high fentanyl exposure observed in our sample suggests a need to address upstream structural factors shaping the overdose risk in addition to individual behavioral change.

Canadian clinical practice guidelines for the use of plant-based cannabis and cannabinoid-based products in the management of chronic non-cancer pain and co-occurring conditions: protocol for a systematic literature review

INTRODUCTION

Chronic pain and co-occurring disorders, such as sleep disorders, anxiety, depression, post-traumatic stress disorder and substance use disorders, are among the most common conditions for which cannabis and cannabinoid-based products derived from the cannabis plant (CBP) are used for therapeutic purposes. However, healthcare providers report that they lack sufficient information on the risks, benefits and appropriate use of cannabis and CBP derived from the cannabis plant for therapeutic purposes.

METHODS AND ANALYSIS

We will conduct a systematic review of studies investigating the use of cannabis and CBP derived from the cannabis plant for the treatment of chronic pain and co-occurring conditions. Randomised controlled trials, meta-analyses and observational studies will be prioritised. We will exclude reviews of cannabinoid mechanisms of actions, commentary articles and narrative reviews. The primary outcome of interest will be efficacy in relieving chronic pain. Secondary outcomes will be efficacy in ameliorating conditions such as sleep disorders, anxiety, depression, post-traumatic stress disorder and substance use disorders. We will search electronic bibliographic databases including Academic Search Complete, Cochrane Database of Systematic Reviews, Evidence based Medicine Reviewes, OVID Medline, PsychINFO, PubMed, CINAHL and Web of Science. Two reviewers will conduct screening and data collection independently. Study level of bias will be assessed using the Cochrane Risk of Bias Assessment Tool for randomised controlled trials and non-randomised studies. Narrative analysis will be utilised to interpret the data.

ETHICS AND DISSEMINATION

The results of this systematic review will inform guideline development for the use of cannabis and CBP derived from the cannabis plant in the management of chronic pain and co-occurring conditions. Areas requiring further study will also be highlighted.

PROSPERO REGISTRATION NUMBER

CRD42020135886.

Temporal changes in non-fatal opioid overdose patterns among people who use drugs in a Canadian setting

Background and Aims: Little is known about how the expansion of opioid agonist therapy (OAT) and emergence of fentanyl in the illicit drug supply in North America has influenced non-fatal opioid overdose (NFOD) risk. Therefore, we sought to identify patterns of substance use and addiction treatment engagement (i.e., OAT, other inpatient or outpatient treatment) prior to NFOD, as well as the trends and correlates of each pattern among people who use drugs (PWUD) in Vancouver, Canada. Methods: Data were derived from participants in three prospective cohorts of PWUD in Vancouver in 2009-2016. Observations from participants reporting opioid-related NFOD in the previous six months were included. A latent class analysis was used to identify classes based on substances used at the time of last NFOD and addiction treatment engagement in the month prior to the last NFOD. Multivariable generalized estimating equations estimated the correlates of each class membership. Results: In total, 889 observations from 570 participants were included. Four distinct classes were identified: (1) polysubstance use (PSU) and addiction treatment engagement; (2) PSU without treatment engagement; (3) exposure to unknown substances, mostly without treatment engagement; and (4) primary heroin users without treatment engagement. The class of exposure to unknown substances appeared in 2015 and became the dominant group (76.9%) in 2016. In multivariable analyses, the odds of membership in the class of primary heroin users decreased over time (adjusted odds ratio [AOR]: 0.74, 95% confidence interval [CI]: 0.68-0.81). Conclusions: Changing profiles of PWUD reporting opioid-related NFOD were seen over time. Notably, there was a sudden increase in reports of overdose following exposure to unknown substances since 2015, the majority of whom reported no recent addiction treatment engagement. Further study into patterns of substance use and strategies to improve addiction treatment engagement is needed to improve and focus overdose prevention efforts.

The emergence of innovative cannabis distribution projects in the downtown eastside of Vancouver, Canada

The ongoing overdose crisis in the United States and Canada has highlighted the urgent need for innovative interventions to reduce drug-related harms. This, in turn, has led to increased interest in the potential of cannabis as a harm reduction strategy. While Canada has recently legalized cannabis, meaningful barriers to accessing legal cannabis remain for people who use drugs (PWUD) from marginalized communities. In the Downtown Eastside of Vancouver, Canada, innovative, grassroots cannabis distribution programs that dispense cannabis and cannabis products from unregulated sources to PWUD for free have recently emerged. In this study, we draw upon 23 in-depth qualitative interviews and ethnographic fieldwork with PWUD who access these programs. We found that these distribution programs play an important function in bridging access to cannabis for PWUD in a structurally disadvantaged neighborhood and do so by implementing few restrictions on who can access, providing a variety of cannabis products that would otherwise be inaccessible, and distributing cannabis at no cost. In addition, many people reported the program spaces provided an avenue to socialize and connect. Most of our participants reported that legal cannabis was inaccessible both through the legal medical and non-medical systems. Considering Canadian governments have made important regulatory changes in regards to cannabis, understanding emerging patterns and the structural barriers to accessing legal cannabis will be critical to maximizing the potential uses of cannabis as a harm reduction tool and ensuring equitable access to structurally disadvantaged populations. Examining the impact of cannabis use on PWUD and ensuring these groups have access to cannabis is an important component in determining whether cannabis deregulation reduces drug-related harms.

"Am I gonna get in trouble for acknowledging my will to be safe?": Identifying the experiences of young sexual minority men and substance use in the context of an opioid overdose crisis

BACKGROUND

North America and other parts of the globe are in the midst of a public health emergency related to opioid overdoses and a highly contaminated illicit drug supply. Unfortunately, there is a substantial gap in our understandings about how this crisis affects key populations not conventionally identified within overdose-related surveillance data. This gap is particularly pronounced for gay, bisexual, and other men who have sex with men (sexual minority men)-a population that experiences substance use-related inequities across adolescence and young adulthood.

METHODS

We draw on in-depth semi-structured interviews conducted in 2018 with a diverse sample (N = 50) of sexual minority men ages 15-30 who use substances and live in Vancouver, Canada, to identify how patterns and contexts of substance use are occurring in the context of the opioid overdose crisis.

RESULTS

Our analysis revealed three themes: awareness, perceptions, and experiences of risk; strategies to mitigate risk; and barriers to safer substance use. First, participants described how they are deeply impacted by the contaminated illicit drug supply, and how there is growing apprehension that fatal and non-fatal overdose risk is high and rising. Second, participants described how procuring substances from "trustworthy" drug suppliers and other harm reduction strategies (e.g., drug checking technologies, Naloxone kits, not using alone) could reduce overdose risk. Third, participants described how interpersonal, service-related, and socio-structural barriers (e.g., drug criminalization and the lack of a regulated drug supply) limit opportunities for safer substance use.

CONCLUSIONS

Equity-oriented policies and programming that can facilitate opportunities for safer substance use among young sexual minority men are critically needed, including community- and peer-led initiatives, access to low-barrier harm reduction services within commonly frequented social spaces (e.g., Pride, night clubs, bathhouses), nonjudgmental and inclusive substance use-related health services, the decriminalization of drug use, and the provision of a safe drug supply.

Known fentanyl use among clients of harm reduction sites in British Columbia, Canada

BACKGROUND

North America is in the midst of an opioid overdose epidemic and it is commonly suggested that exposure to fentanyl is unknown. Using a provincial survey of harm reduction site clients, we aimed to characterize known and unknown fentanyl use and their correlates among people who use drugs in British Columbia, Canada.

METHODS

We recruited 486 clients who were >18 years old and 316 agreed to provide a urine sample for substance use testing. Reported known fentanyl use was defined as a three-level categorical variable assessing recent (i.e., in the previous three days) fentanyl exposure: (i) known exposure; (ii) unknown exposure; and (iii) no exposure. We also assessed any exposure to fentanyl (Yes vs. No) confirmed by urinalysis. Survey data were summarized using descriptive statistics. Multinomial logistic regression and modified Poisson regression models were built to examine different correlates of exposure to fentanyl.

RESULTS

Median age of the participants was 40 (IQR: 32-49). Out of the 303 eligible participants, 38.7% (117) reported known fentanyl use, 21.7% (66) had unknown fentanyl use, and 39.6% (120) had no recent fentanyl use. In the adjusted multinomial logistic regression model and in comparison with unknown fentanyl use, recent known fentanyl use was significantly associated with self-report of methadone use (aRRR = 3.18), heroin/morphine use (aRRR = 4.40), and crystal meth use (aRRR = 2.95). Moreover, any recent exposure to fentanyl (i.e., positive urine test for fentanyl) was significantly associated with living in urban settings (aPR = 1.49), and self-reporting recent cannabis use (aPR = 0.73), crystal meth (aPR = 1.45), and heroin/morphine use (aPR = 2.48).

CONCLUSION

The landscape of illicit opioid use is changing in BC and more people are using fentanyl knowingly. The increasing prevalence of known fentanyl use is concerning and calls for further investments in public awareness and public policy efforts regarding fentanyl exposure and risks.

Moving into an urban drug scene among people who use drugs in Vancouver, Canada: Latent class growth analysis

Background

Urban drug scenes are characterized by high prevalence of illicit drug dealing and use, violence and poverty, much of which is driven by the criminalization of people who use illicit drugs (PWUD) and the associated stigma. Despite significant public health needs, little is understood about patterns of moving into urban drug scenes among PWUD. Therefore, we sought to identify trajectories of residential mobility (hereafter ‘mobility’) among PWUD into the Downtown Eastside (DTES), an urban neighbourhood with an open drug scene in Vancouver, Canada, as well as characterize distinct trajectory groups among PWUD.

Methods

Data were derived from three prospective cohort studies of community-recruited PWUD in Vancouver between 2005 and 2016. We used latent class growth analysis (LCGA) to identify distinct patterns of moving into the DTES among participants residing outside of DTES at baseline. Multivariable multinomial logistic regression was used to determine baseline factors associated with each trajectory group.

Results

In total, 906 eligible participants (30.9% females) provided 9,317 observations. The LCGA assigned four trajectories: consistently living outside of DTES (52.8%); early move into DTES (11.9%); gradual move into DTES (19.5%); and move in then out (15.8%). Younger PWUD, those of Indigenous ancestry, those who were homeless or living in a single-room occupancy hotel (SRO), and those injecting drugs daily were more likely to move in then out of DTES (all p<0.05). Living in an SRO, daily injection drug use, and recent incarceration were also positively associated with early mobility (all p<0.05).

Conclusions

Nearly half of the participants moved into the DTES. Younger PWUD and Indigenous peoples appeared to have particularly high mobility, as did those with markers of social-structural vulnerability and high intensity drug use. These findings indicate a need to tailor existing social and health services within the DTES and expand affordable housing options outside the DTES.

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.