Would legalizing illicit opioids reduce overdose fatalities? Implications from a natural experiment

Warning Labels as a Public Health Intervention: Effects and Challenges for Tobacco, Cannabis, and Opioid Medications

Warning labels help consumers understand product risks, enabling informed decisions. Since the 1966 introduction of cigarette warning labels in the United States, research has determined the most effective message content (health effects information) and format (brand-free packaging with pictures). However, new challenges have emerged. This article reviews the current state of tobacco warning labels in the United States, where legal battles have stalled pictorial cigarette warnings and new products such as electronic cigarettes and synthetic nicotine products pose unknown health risks. This article describes the emerging research on cannabis warnings; as more places legalize recreational cannabis, they are adopting lessons from tobacco warnings. However, its uncertain legal status and widespread underestimation of harms impede strict warning standards. The article also reviews opioid medication warning labels, suggesting that lessons from tobacco could help in the development of effective and culturally appropriate FDA-compliant opioid warning labels that promote safe medication use and increased co-dispensing of naloxone.

The Therapeutic Potential and Molecular Mechanisms Underlying the Neuroprotective Effects of Sativex® - A Cannabis-derived Spray

Sativex is a cannabis-based medicine that comes in the form of an oromucosal spray. It contains equal amounts of Δ9-tetrahydrocannabinol and cannabidiol, two compounds derived from cannabis plants. Sativex has been shown to have positive effects on symptoms of amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and sleep disorders. It also has analgesic, antiinflammatory, antitumoral, and neuroprotective properties, which make it a potential treatment option for other neurological disorders. The article reviews the results of recent preclinical and clinical studies that support the therapeutic potential of Sativex and the molecular mechanisms behind its neuroprotective benefits in various neurological disorders. The article also discusses the possible advantages and disadvantages of using Sativex as a neurotherapeutic agent, such as its safety, efficacy, availability, and legal status.

"They sent it away for testing and it was all bunk": Exploring perspectives on drug checking among steroid consumers in Queensland, Australia

INTRODUCTION

Research supports the feasibility and acceptance of drug checking among nightlife and festival attendees. Interest in expanding drug checking to other groups of people who use drugs, including those who inject drugs, has grown. However, understanding the acceptability and feasibility of drug checking among specific cohorts, like anabolic-androgenic steroids (AAS) consumers, remains a research gap. This study explores AAS consumers' perspectives on drug checking and service preferences, aiding the preparation for drug checking delivery in Queensland, Australia.

METHODS

A purposive sampling technique was used to recruit 15 AAS consumers (9 males, 6 females; Mage = 36.80 years, SD = 6.12) from Australia. One-on-one semi-structured qualitative interviews were conducted with questions exploring participants' views on drug checking/testing and their preferences for AAS analysis. Thematic analysis was conducted with final themes established through iterative consensus.

RESULTS

Consumers expressed frustration with the prevailing stereotypes, social stigma, and the perception of criminality associated with the use of AAS. There was a strong dependence on personal connections and trusted suppliers, with coaches exerting significant influence. Participants expressed concerns about the widespread availability of counterfeit products and underground operations. The act of using unknown AAS was likened to a game of Russian roulette, underscoring the importance of obtaining accurate information and access to reliable drug checking services. Consumers expressed a preference for a web-based platform that enables individuals to access their own test results while contributing to a comprehensive database of brand-specific testing outcomes.

DISCUSSION

AAS consumers recognise the significance of monitoring their AAS use and seek a service that can not only assist them in making informed decisions regarding AAS usage but also potentially contribute to the knowledge of the wider AAS-consuming community. These findings underscore the importance of tailored education, drug checking services, and harm reduction measures to address the diverse needs of AAS consumers.

Heroin-induced respiratory depression and the influence of dose variation: within-subject between-session changes following dose reduction

BACKGROUND AND AIMS

Globally, more than 100 000 people die annually from opioid overdose. Opportunities to study physiological events in at-risk individuals are limited. This study examined variation of opioid dose and impact on respiratory depression in a chronic injecting heroin user at separate time-points during his long-term diamorphine maintenance treatment.

DESIGN

A single-subject study over 5 years during which participant underwent experimental studies on diamorphine-induced respiratory depression, at changing maintenance doses.

SETTING

A clinical research facility. Participant Male subject on long-term injectable diamorphine (pharmaceutical heroin) maintenance treatment for heroin addiction.

MEASUREMENTS

Physiological measures of oxygen saturation (SpO₂ ), end-tidal carbon dioxide (ETCO₂ ) and respiratory rate (RR) were used to indicate severity of respiratory depression.

FINDINGS

(1) After diamorphine injection, respiratory regulation became abnormal, with prolonged apnoea exceeding 20 sec (maximum 56 sec), elevated ETCO₂ (maximum 6.9%) and hypoxaemia (minimum SpO₂ 80%). (2) Abnormalities were greater with highest diamorphine dose: average SpO₂ was 89.3% after 100 mg diamorphine versus 93.6% and 92.8% for the two 30-mg doses. (3) However, long apnoeic pauses and high levels of ETCO₂ % were also present after lower doses.

CONCLUSIONS

With marked inter-session variability, these findings corroborate observations of inconsistent relationships between opioid dose and overdose risk.

Illicit opioid use following changes in opioids prescribed for chronic non-cancer pain

Background

After decades of increased opioid pain reliever prescribing, providers are rapidly reducing prescribing. We hypothesized that reduced access to prescribed opioid pain relievers among patients previously reliant upon opioid pain relievers would result in increased illicit opioid use.

Methods and findings

We conducted a retrospective cohort study among 602 publicly insured primary care patients who had been prescribed opioids for chronic non-cancer pain for at least three consecutive months in San Francisco, recruited through convenience sampling. We conducted a historical reconstruction interview and medical chart abstraction focused on illicit substance use and opioid pain reliever prescriptions, respectively, from 2012 through the interview date in 2017–2018. We used a nested-cohort design, in which patients were classified, based on opioid pain reliever dose change, into a series of nested cohorts starting with each follow-up quarter. Using continuation-ratio models, we estimated associations between opioid prescription discontinuation or 30% increase or decrease in dose, relative to no change, and subsequent frequency of heroin and non-prescribed opioid pain reliever use, separately. Models controlled for demographics, clinical and behavioral characteristics, and past use of heroin or non-prescribed opioid pain relievers. A total of 56,372 and 56,484 participant-quarter observations were included from the 597 and 598 participants available for analyses of heroin and non-prescribed opioid pain reliever outcomes, respectively. Participants discontinued from prescribed opioids were more likely to use heroin (Adjusted Odds Ratio (AOR) = 1.57, 95% CI: 1.25–1.97) and non-prescribed opioid pain relievers (AOR = 1.75, 1.45–2.11) more frequently in subsequent quarters compared to participants with unchanged opioid prescriptions. Participants whose opioid pain reliever dose increased were more likely to use heroin more frequently (AOR = 1.67, 1.32–2.12). Results held throughout sensitivity analyses. The main limitations were the observational nature of results and limited generalizability beyond safety-net settings.

Conclusions

Discontinuation of prescribed opioid pain relievers was associated with more frequent non-prescribed opioid pain reliever and heroin use; increased dose was also associated with more frequent heroin use. Clinicians should be aware of these risks in determining pain management approaches.

Nabiximols for the Treatment of Cannabis Dependence: A Randomized Clinical Trial

IMPORTANCE

There are no effective medications for treating dependence on cannabis.

OBJECTIVE

To examine the safety and efficacy of nabiximols in the treatment of patients with cannabis dependence.

DESIGN, SETTING, AND PARTICIPANTS

This parallel double-blind randomized clinical trial comparing nabiximols with placebo in a 12-week, multisite outpatient study recruited participants from February 3, 2016, to June 14, 2017, at 4 outpatient specialist alcohol and drug treatment services in New South Wales, Australia. Participants had cannabis dependence (as defined by the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision) and were seeking treatment, were nonresponsive to prior treatment attempts, were 18 to 64 years of age, had no other substance use disorder, had no severe medical or psychiatric conditions, were not pregnant, were not mandated by a court to undergo treatment, and provided informed consent. Results for primary efficacy measures and all secondary outcomes were obtained using a modified intention-to-treat data set.

INTERVENTIONS

Participants received 12-week treatment involving weekly clinical reviews, structured counseling, and flexible medication doses-up to 32 sprays daily (tetrahydrocannabinol, 86.4 mg, and cannabidiol, 80 mg), dispensed weekly.

MAIN OUTCOMES AND MEASURES

Primary outcome was self-reported number of days using illicit cannabis during the 12-week period. Other outcomes included alternate cannabis use parameters (periods of abstinence, withdrawal, cravings, and problems), safety parameters (adverse events and aberrant medication use), health status, other substance use, and treatment retention.

RESULTS

A total of 128 participants (30 women and 98 men; mean [SD] age, 35.0 [10.9] years) were randomized and received at least 1 dose of study medication. Participants had used a mean (SD) of 2.3 (2.1) g of cannabis on a mean (SD) of 25.7 (4.5) days in the past 28 days. Treatment retention was comparable for the 2 groups (placebo, 30 of 67 participants [44.8%]; nabiximols, 30 of 61 participants [49.2%]), and both groups used similar mean (SD) doses (placebo, 18.5 [9.5] sprays daily; nabiximols, 17.6 [9.5] sprays daily, equivalent to a mean [SD] of 47.5 [25.7] mg of tetrahydrocannabinol and 44.0 [23.8] mg of cannabidiol). For the primary end point, the placebo group reported significantly more days using cannabis during the 12 weeks (mean [SD], 53.1 [33.0] days) than the nabiximols group (mean [SD], 35.0 [32.4] days; estimated difference, 18.6 days; 95% CI, 3.5-33.7 days; P = .02). Both groups showed comparable improvements in health status, with no substantial changes in other substance use. Medication was well tolerated with few adverse events.

CONCLUSIONS AND RELEVANCE

This study demonstrates that cannabinoid agonist treatment, in this case using nabiximols, in combination with psychosocial interventions is a safe approach for reducing cannabis use among individuals with cannabis dependence who are seeking treatment.

TRIAL REGISTRATION

anzctr.org.au Identifier: ACTRN12616000103460.

Prediction of psychiatric comorbidity on premature death in a cohort of patients with substance use disorders: a 42-year follow-up

BACKGROUND

We need to better understand how the use of different substances and psychiatric comorbidity influence premature death generally and cause-specific death by overdose, intoxication and somatic disorders in people with substance use disorders.

METHOD

A cohort of 1405 patients consecutively admitted to a Swedish detoxification unit for substance use disorders in 1970-1995 was followed-up for 42 years. Substances were identified by toxicological analyses. Mortality figures were obtained from a national registry. Causes of death were diagnosed by forensic autopsy in 594 patients deceased by 2012. Predictions were calculated by competing risks analysis.

RESULTS

Forty-two per cent of the cohort died during follow-up; more men than women (46.3% vs 30.4%). The standardised mortality ratio (SMR) was calculated as the ratio of observed deaths in males and females in specific age groups in the cohort versus expected deaths in corresponding groups in the general population. SMR was 5.68 for men (CI 95%; 5.04-6.11) and 4.98 (CI 95%; 4.08-5.88) for women. The crude mortality rate (number of deaths divided by number of person observation years) was 2.28% for men and 1.87% for women. Opiates predicted increased risk of premature death while amphetamine and cannabis predicted lower risk. Comorbid psychiatric disorders were identified in 378 cases and personality disorders in 763 cases. Primary psychoses or mood/depression and anxiety disorders predicted a higher risk of premature mortality. Death by overdose was predicted by male gender, younger age at admission to substance treatment, opiate use, and comorbid depression and anxiety syndromes. Cannabis and amphetamine use predicted a lower risk of overdose. Death by intoxication was predicted by male gender, use of sedatives/hypnotics or alcohol/mixed substances, primary psychoses and depression/anxiety syndromes. Premature death by somatic disorder was predicted by male gender and alcohol/mixed abuse.

CONCLUSION

Psychiatric comorbid disorders were important risk factors for premature drug-related death. Early identification of these factors may be life-saving in the treatment of patients with substance use disorders.

Factors Associated with Nonfatal Overdose During a Public Health Emergency

BACKGROUND

In 2016, in the Canadian province of British Columbia, the Provincial Health Officer declared drug-related overdose deaths a public health emergency.

OBJECTIVES

In this study, we examine factors associated with recent non-fatal overdose during a time of unprecedented rates of overdose and increasing involvement of fentanyl and fentanyl derivatives in overdose deaths.

METHODS

Between June and September 2016, a cross-sectional survey was conducted among people who inject drugs (PWID) in Victoria, British Columbia, Canada. Bivariable and multivariable logistic regression analyses were used to examine factors associated with recent non-fatal overdose.

RESULTS

A total of 187 PWID were included in the present study, of whom 56 (29.9%) reported having overdosed in the previous 6 months. In multivariable analyses, fentanyl injection (Adjusted Odds Ratio [AOR] = 2.60; 95% confidence interval [CI]: (1.08 - 6.27) and public injection (AOR = 2.20; 95% CI: 1.09 - 4.43) were positively associated with recent non-fatal overdose.

CONCLUSIONS

Fentanyl injection and public injection were associated with an increased likelihood of non-fatal overdose. These findings underscore the need for drug checking, safer sources of opioids and safer injecting interventions as part of overdose prevention strategies.

The future of the international drug control system and national drug prohibitions

A major impediment to any nation abandoning the policy of drug prohibition has been the fact that international drug treaties to which the majority of United Nations (UN) member states are signatory prohibit the non-medical use of amphetamines, cannabis, cocaine and heroin. The future of these treaties is now uncertain because of decisions by Uruguay, eight US states and Canada to legalize cannabis use. This paper: (1) provides a brief account of the international drug control treaties; (2) outlines the major criticisms of the treaties; (3) analyses critically proposals for treaty reform; and (4) provides a personal view on policies that nation states could adopt to minimize the harms from the use of cannabis, party drugs and hallucinogens, opioids, stimulants and new psychoactive substances. It is argued that: a major risk of cannabis legalization in the United States is promotion of heavy use and increased harm by a weakly regulated industry; some cautious national experiments with the regulation of party drugs and hallucinogens would be informative; a strong case remains for prohibiting the nonmedical use of opioids while mitigating the adverse effects that this policy has on opioid-dependent people; stimulant legalization will probably increase problem use but prohibition is difficult to enforce, highlighting the urgency of finding better ways to reduce demand for these drugs and respond to problem users; and that it is unclear what the best approach is to reducing possible harms that may arise from the use of new psychoactive substances.

Assessing the effectiveness of New York's 911 Good Samaritan Law-Evidence from a natural experiment

BACKGROUND

Drug overdose is the leading cause of accidental death in the United States. Nationally, opioids are the primary drugs associated with accidental overdoses. In response to increasing overdose deaths, 40 states and the District of Columbia have enacted Good Samaritan Laws (GSLs). Generally, these policies attempt to encourage witnesses or those experiencing an overdose to call 911 by providing limited immunity from arrest, charge and/or prosecution of possession of narcotics. The aim of the current study is to evaluate the effectiveness of New York State's 911 GSL.

METHODS

We exploit a difference in state law between New York State, where the policy was adopted in 2011, and New Jersey, where the policy was not adopted until 2013, to provide a reasonable comparison condition. We examine variation in accidental opioid overdose emergency department visits and inpatient admissions from 2010 to 2012 across 270 hospitals in New York and New Jersey at the quarterly level controlling for hospital fixed effects and time trends using State Emergency Department Databases (SEDD) and State Inpatient Databases (SID).

RESULTS

Accidental opioid overdose emergency department visits and inpatient hospital admissions were increasing in both New York and New Jersey. After the enactment of New York's 911 GSL, emergency department visits and inpatient hospital admissions for accidental heroin overdoses increased differently in New York and New Jersey, with an incident rate ratio (IRR) of 1.34 (95% CI = 1.00, 1.86). The results were inconclusive for accidental non-heroin opioid overdoses (IRR = 0.98, 95% CI = 0.86, 1.13).

CONCLUSIONS

Accidental heroin overdose emergency department visits and inpatient hospital admissions increased in New York State after the enactment of the 911 GSL, consistent with the intended effect of the GSL. Preliminary evidence suggests that either persons who use heroin and/or those around them were impacted by the policy change.

Randomised Controlled Trial (RCT) of cannabinoid replacement therapy (Nabiximols) for the management of treatment-resistant cannabis dependent patients: a study protocol

BACKGROUND

The cannabis extract nabiximols (Sativex®) effectively supresses withdrawal symptoms and cravings in treatment resistant cannabis dependent individuals, who have high relapse rates following conventional withdrawal treatments. This study examines the efficacy, safety and cost-effectiveness of longer-term nabiximols treatment for outpatient cannabis dependent patients who have not responded to previous conventional treatment approaches.

METHODS/DESIGN

A phase III multi-site outpatient, randomised, double-blinded, placebo controlled parallel design, comparing a 12-week course of nabiximols to placebo, with follow up at 24 weeks after enrolment. Four specialist drug and alcohol outpatient clinics in New South Wales, Australia. One hundred forty-two treatment seeking cannabis dependent adults, with no significant medical, psychiatric or other substance use disorders. Nabiximols is an oromucosal spray prescribed on a flexible dose regimen to a maximum daily dose of 32 sprays; 8 sprays (total 21.6 mg tetrahydrocannabinol (THC) and 20 mg cannabidiol (CBD)) four times a day, or matching placebo, dispensed weekly. All participants will receive six-sessions of individual cognitive behavioural therapy (CBT) and weekly clinical reviews. Primary endpoints are use of non-prescribed cannabis (self-reported cannabis use days, urine toxicology), safety measures (adverse events and abuse liability), and cost effectiveness (incremental cost effectiveness in achieving additional Quality Adjusted Life Years). Secondary outcomes include, improvement in physical and mental health parameters, substance use other than cannabis, cognitive functioning and patient satisfaction measures.

DISCUSSION

This is the first outpatient community-based randomised controlled study of nabiximols as an agonist replacement medication for treating cannabis dependence, targeting individuals who have not previously responded to conventional treatment approaches. The study and treatment design is modelled upon an earlier study with this population and more generally on other agonist replacement treatments (e.g. nicotine, opioids).

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry: ACTRN12616000103460 (Registered 1st February 2016).

Frequency and severity of non-fatal opioid overdoses among clients attending the Sydney Medically Supervised Injecting Centre

BACKGROUND

Pharmaceutical opioid overdose rates have increased in recent years. The current study aimed to compare rates per 1000 injections of non-fatal overdose after heroin or oxycodone injection, and their comparative clinical severity.

METHODS

Analysis of prospectively collected data from the Sydney Medically Supervised Injecting Centre (MSIC). Severity of overdose was measured using the Glasgow Coma Scale, oxygen saturation levels, and the administration of naloxone.

RESULTS

Heroin overdoses occurred at three times the rate of oxycodone overdoses (12.7 v 4.1 per 1000 injections). Heroin overdoses appeared to be more severe than oxycodone overdoses, with higher levels of compromised consciousness (31 v 18%) and severe respiratory depression (67 v 48%), but there were no differences in naloxone doses (20 v 17%). Concurrent use of other depressants at the time of overdose was also associated with compromised consciousness, and the need for naloxone.

CONCLUSIONS

Heroin overdoses occurred at a greater rate than oxycodone overdoses, and had more severe clinical indicators.

Evaluating the impact of a national naloxone programme on ambulance attendance at overdose incidents: a controlled time-series analysis

BACKGROUND AND AIMS

It has been suggested that distributing naloxone to people who inject drugs (PWID) will lead to fewer attendances by emergency medical services at opioid-related overdose incidents if peer administration of naloxone was perceived to have resuscitated the overdose victim successfully. This study evaluated the impact of a national naloxone programme (NNP) on ambulance attendance at opioid-related overdose incidents throughout Scotland. Specifically, we aimed to answer the following research questions: is there evidence of an association between ambulance call-outs to opioid-related overdose incidents and the cumulative number of 'take-home naloxone' (THN) kits in issue; and is there evidence of an association between ambulance call-outs to opioid-related overdose incidents in early adopter (pilot) or later adopting (non-pilot) regions and the cumulative number of THN kits issued in those areas?

DESIGN

Controlled time-series analysis.

SETTING

Scotland, UK, 2008-15.

PARTICIPANTS

Pre-NNP implementation period for the evaluation was defined as 1 April 2008 to 31 March 2011 and the post-implementation period as 1 April 2011 to 31 March 2015. In total, 3721 ambulance attendances at opioid-related overdose were recorded for the pre-NNP implementation period across 158 weeks (mean 23.6 attendances per week) and 5258 attendances across 212 weeks in the post-implementation period (mean 24.8 attendances per week).

INTERVENTION

Scotland's NNP; formally implemented on 1 April 2011.

MEASUREMENTS

Primary outcome measure was weekly incidence (counts) of call-outs to opioid-related overdoses at national and regional Health Board level. Data were acquired from the Scottish Ambulance Service (SAS). Models were adjusted for opioid replacement therapy using data acquired from the Information Services Division on monthly sums of all dispensed methadone and buprenorphine in the study period. Models were adjusted further for a control group: weekly incidence (counts) of call-outs to heroin-related overdose in the London Borough area acquired from the London Ambulance Service.

FINDINGS

There was no significant association between SAS call-outs to opioid-related overdose incidents and THN kits in issue for Scotland as a whole (coefficient 0.009, 95% confidence intervals = -0.01, 0.03, P = 0.39). In addition, the magnitude of association between THN kits and SAS call-outs did not differ significantly between pilot and non-pilot regions (interaction test, P = 0.62).

CONCLUSIONS

The supply of take-home naloxone kits through a National Naloxone Programme in Scotland was not associated clearly with a decrease in ambulance attendance at opioid-related overdose incidents in the 4-year period after it was implemented in April 2011.

High risk injecting behaviour among people who inject pharmaceutical opioids in Australia

BACKGROUND

Use of opioid analgesic medicines has doubled globally over the past decade, with a concomitant increase in prevalence of injection of pharmaceutical opioids (PO), including in Australia. This study investigates types of PO injected, methods used to prepare PO for injection and correlates of recent (last 6 months) PO injection among a large national sample of people who inject drugs (PWID).

METHODS

The Australian NSP Survey (ANSPS), conducted annually at ∼50 NSP services across Australia, consists of a brief self-administered questionnaire and provision of a capillary dried blood spot for HIV and hepatitis C antibody testing. Data from 2014 were used to conduct univariable and multivariable logistic regression analysis to determine factors independently associated with recent injection of PO.

RESULTS

Among 1488 ANSPS respondents who were identified as opioid injectors, 57% (n=848) reported injection of PO in the previous six months. The majority of PO injectors (85%) reported filtering PO prior to injection, although use of efficacious wheel filters was relatively rare (11%). Correlates of POs injection included daily injection (AOR=1.65, 95% CI 1.31-2.08), receptive sharing of syringes (AOR=2.00, 95% CI 1.43-2.78), receptive sharing of drug preparation equipment (AOR=1.55, 95% CI 1.19-2.01), drug overdose in the previous year (AOR=1.81, 95% CI 1.36-2.42) and residence in inner regional (AOR=3.27, 95% CI 2.21-5.23) or outer regional/remote (AOR=5.50, 95% CI 3.42-8.84) areas of Australia.

CONCLUSION

PO injection is geographically widespread among Australian PWID and takes place in the context of poly-drug use. People who inject POs are at high risk of overdose, injection related injury and disease and blood borne viral infections. Harm reduction services that target this group, including in non-urban areas, should deliver health education regarding PO-specific overdose risks, the requirement to adequately filter PO before injection and to ensure that both naloxone and specialist pill filters are readily accessible.

Concepts of illicit drug quality among darknet market users: Purity, embodied experience, craft and chemical knowledge

BACKGROUND

Users of darknet markets refer to product quality as one of the motivations for buying drugs there, and vendors present quality as a selling point. However, what users understand by quality and how they evaluate it is not clear. This article investigates how users established and compared drug quality.

METHODS

We used a two-stage method for investigating users' assessments. The user forum of a darknet market that we called 'Merkat' was analysed to develop emergent themes. Qualitative interviews with darknet users were conducted, then forum data was analysed again. To enhance the applicability of the findings, the forum was sampled for users who presented as dependent as well as recreational.

RESULTS

Quality could mean reliability, purity, potency, and predictability of effect. We focused on the different kinds of knowledge users drew on to assess quality. These were: embodied; craft; and chemical.

CONCLUSION

Users' evaluations of quality depended on their experience, the purpose of use, and its context. Market forums are a case of indigenous harm reduction where users share advise and experiences and can be usefully engaged with on these terms.

The effect of prescription opioid injection on the risk of non-fatal overdose among people who inject drugs

OBJECTIVES

Prescription opioid (PO) use by people who inject drugs (PWID) is a growing public health concern. Non-fatal overdose remains a leading source of morbidity among PWID, however, little is known about the relationship between PO injection and non-fatal overdose in this population. In this study we sought to examine the impact of PO injection on non-fatal overdose among PWID from Vancouver, Canada.

METHODS

Data were derived from two open prospective cohorts of PWID for the period of December, 2005 to May, 2014. Multivariable generalized estimating equations were used to examine the odds of overdose among those who injected: POs; heroin; and POs and heroin.

RESULTS

In total, 1660 PWID (33.7% women) participated in this study. In multivariable analyses, in comparison to those who were injecting non-opioid drugs, exclusive PO injection was not significantly associated with non-fatal overdose (adjusted odds ratio [AOR]: 1.17, 95% confidence interval [CI]: 0.74-1.86). The odds of non-fatal overdose were elevated for heroin injection (AOR: 1.72, 95% CI: 1.31-2.27), but were greatest for those who injected both heroin and POs (AOR: 2.46, 95% CI: 1.83-3.30).

DISCUSSION

Compared to injecting non-opioids, injecting POs exclusively did not increase risk of non-fatal overdose; however, injecting both POs and heroin doubled the risk. This may reflect consistencies in drug potency and composition when POs are used, as well as unique characteristics of exclusive PO injectors. Our findings call for the continued scale-up of evidence-based overdose prevention interventions for people who inject opioids, including POs.

The relationship between US heroin market dynamics and heroin-related overdose, 1992-2008

BACKGROUND AND AIMS

Heroin-related overdose is linked to polydrug use, changes in physiological tolerance and social factors. Individual risk can also be influenced by the structural risk environment including the illicit drug market. We hypothesized that components of the US illicit drug market, specifically heroin source/type, price and purity, will have independent effects on the number of heroin-related overdose hospital admissions.

METHODS

Yearly, from 1992 to 2008, Metropolitan Statistical Area (MSA) price and purity series were estimated from the US Drug Enforcement Administration data. Yearly heroin overdose hospitalizations were constructed from the Nationwide Inpatient Sample. Socio-demographic variables were constructed using several databases. Negative binomial models were used to estimate the effect of price, purity and source region of heroin on yearly hospital counts of heroin overdoses controlling for poverty, unemployment, crime, MSA socio-demographic characteristics and population size.

RESULTS

Purity was not associated with heroin overdose, but each $100 decrease in the price per pure gram of heroin resulted in a 2.9% [95% confidence interval (CI) = 4.8%, 1.0%] increase in the number of heroin overdose hospitalizations (P = 0.003). Each 10% increase in the market share of Colombian-sourced heroin was associated with a 4.1% (95% CI = 1.7%, 6.6%) increase in number of overdoses reported in hospitals (P = 0.001) independent of heroin quality.

CONCLUSIONS

Decreases in the price of pure heroin in the United States are associated with increased heroin-related overdose hospital admissions. Increases in market concentration of Colombian-source/type heroin is also associated with an increase in heroin-related overdose hospital admissions. Increases in US heroin-related overdose admissions appear to be related to structural changes in the US heroin market.