How do drug market changes affect characteristics of injecting initiation and subsequent patterns of drug use? Findings from a cohort of regular heroin and methamphetamine injectors in Melbourne, Australia

Horyniak, Danielle; Stoové, Mark; Degenhardt, Louisa; Aitken, Campbell; Dietze, Paul

doi:10.1016/j.drugpo.2014.09.002

Cited by 25 publications

(12 citation statements)

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“…Another reason for drug transition is related to the price and availability of drugs: when MA prices increase, co-users choose to consume more heroin, and vice versa (35). The drug-market period in which injecting initiation occurred sensitively influenced the kind of first injected drug, thereby influencing some aspects of subsequent drug use in Australia (36).The present results provided the first direct evidence for the transition between MA and heroin use due to the reciprocal substitutability of their rewarding effects. The crisis of the global emergence of combining MA with heroin use is merging, and attention should be paid to their negative effects on public health (37).…”

Section: Discussionmentioning

confidence: 99%

Reciprocal Substitution Between Methamphetamine and Heroin in Terms of Reinforcement Effects in Rats

et al. 2020

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Heroin and methamphetamine are both popular illicit drugs in China. Previous clinical data showed that habitual users of either heroin or methamphetamine abuse the other drug for substitution in case of unavailability of their preferred drug. The present study aimed to observe whether heroin can substitute the methamphetamine reinforcement effect in rats, and vice versa. Rats were trained to self-administer heroin or methamphetamine (both 50 mg/kg/infusion) under an FR1 reinforcing schedule for 10 days. After having extracted the dose-effect curve of the two drugs, we administered methamphetamine at different doses (12.5-200 mg/kg/infusion) to replace heroin during the period of self-administration, and vice versa. The heroin dose-effect curve showed an inverted U-shaped trend, and the total intake dose of heroin significantly increased when the training dose increased from 50 to 100 or 200 mg/kg/infusion. Following replacement with methamphetamine, the total dose-effect curve shifted leftwards and upwards. By contrast, although the dose-effect curve of methamphetamine also showed an inverted U-shaped trend, the total dose of methamphetamine significantly decreased when the training dose decreased from 50 to 25 mg/kg/infusion; conversely, when the methamphetamine training dose increased, the total dose did not change significantly. The total dose-effect curve shifted rightwards after heroin was substituted with methamphetamine. Although heroin and methamphetamine had their own independent reward effects, low doses of methamphetamine can replace the heroin reward effect, while high doses of heroin can replace the methamphetamine reward effect. These results demonstrated that heroin and methamphetamine can substitute each other in terms of reinforcement effects in rats.

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Section: Discussionmentioning

confidence: 99%

Reciprocal Substitution Between Methamphetamine and Heroin in Terms of Reinforcement Effects in Rats

et al. 2020

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“…Finally, our participants were recruited from a population with unknown parameters, limiting the generalisability of our findings [37]. …”

Section: Discussionmentioning

confidence: 99%

Individual-level needle and syringe coverage in Melbourne, Australia: a longitudinal, descriptive analysis

O’Keefe

Scott

Aitken

2016

BMC Health Serv Res

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BackgroundCoverage is used as one indicator of needle and syringe program (NSP) effectiveness. At the individual level, coverage is typically defined as an estimate of the proportion of a person who injects drugs’ (PWID) injecting episodes that utilise a sterile syringe. In this paper, we explore levels of individual syringe coverage and its changes over time.MethodsData were extracted from 1889 interviews involving 502 participants drawn from the Melbourne drug user cohort study (MIX).We asked questions relating to participants syringe acquisition, distribution and injecting frequency within the two weeks before interview. We created a dichotomous coverage variable that classified participants as sufficiently (≥100 %) covered if all their injecting episodes utilised at least one sterile syringe, and insufficiently (<100 %) covered if not. We categorised participants as “consistently covered” if they were sufficiently covered across interviews; as “consistently uncovered” if they were insufficiently covered across interviews; and “inconsistently covered” if they oscillated between coverage states.Chi-square statistics tested proportions of insufficient coverage across sub-groups using broad demographic, drug use and service utilisation domains. Logistic regression tested predictors of insufficient coverage and inconsistently covered categorisation.ResultsAcross the sample, levels of insufficient coverage were substantial (between 22–36 % at each interview wave). The majority (50 %) were consistently covered across interviews, though many (45 %) were inconsistently covered.We found strong statistical associations between insufficient coverage and current hepatitis C virus (HCV) infection (RNA+). Current prescription of opioid substitution therapy (OST) and using NSPs as the main source of syringe acquisition were protective against insufficient coverage.ConclusionInsufficient coverage across the sample was substantial and mainly driven by those who oscillated between states of coverage, suggesting the presence of temporal factors. We recommend a general expansion of NSP services and OST prescription to encourage increases in syringe coverage.Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-016-1668-z) contains supplementary material, which is available to authorized users.

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“…Experts have therefore described injecting as a socially communicable condition: a condition spread between individuals through social exposure in an enabling environment (Robertson et al, 2012; Sherman, Smith, Laney, & Strathdee, 2002; Small, Fast, Krusi, Wood, & Kerr, 2009). Adherence to the social communicability of this condition is further influenced by individual, social, and structural factors (Horyniak et al, 2014; Horyniak et al, 2015; Sherman et al, 2002). As such, in settings experiencing syndemics of IDU and blood-borne disease, calls have been made to prioritize the prevention of injection initiation to reduce disease incidence and mitigate other drug-related harms (Bluthenthal & Kral, 2015; Vlahov, Fuller, Ompad, Galea, & Des Jarlais, 2004; Werb et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Injection Drug Use Trajectories among Migrant Populations: A Narrative Review

Melo

Mittal

Horyniak

et al. 2018

Substance Use & Misuse

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Background Dual epidemics of injection drug use and blood-borne disease, characterized as “syndemics,” are present in a range of settings. Behaviors that drive such syndemics are particularly prevalent among mobile drug-using populations, for whom cross-border migration may pose additional risks. Objectives This narrative review aims to characterize the risk factors for injection drug use initiation associated with migration, employing a risk environment framework and focusing on the San Diego–Tijuana border region as the most dynamic example of these phenomena. Methods Based on previous literature, we divide migration streams into three classes: intra-urban, internal, and international. We synthesized existing literature on migration and drug use to characterize how mobility and migration drive the initiation of injection drug use, as well as the transmission of hepatitis and HIV, and to delineate how these might be addressed through public health intervention. Results Population mixing between migrants and receiving communities and the consequent transmission of social norms about injection drug use create risk environments for injection drug use initiation. These risk environments have been characterized as a result of local policy environments, injection drug use norms in receiving communities, migration-related stressors, social dislocation, and infringement on the rights of undocumented migrants. Conclusion Policies that exacerbate risk environments for migrants may inadvertently contribute to the expansion of epidemics of injection-driven blood-borne disease. Successful interventions that address emerging syndemics in border regions may therefore need to be tailored to migrant populations and distinguish between the vulnerabilities experienced by different migration classes and border settings.

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How do drug market changes affect characteristics of injecting initiation and subsequent patterns of drug use? Findings from a cohort of regular heroin and methamphetamine injectors in Melbourne, Australia

Cited by 25 publications

References 49 publications

Reciprocal Substitution Between Methamphetamine and Heroin in Terms of Reinforcement Effects in Rats

Reciprocal Substitution Between Methamphetamine and Heroin in Terms of Reinforcement Effects in Rats

Individual-level needle and syringe coverage in Melbourne, Australia: a longitudinal, descriptive analysis

Injection Drug Use Trajectories among Migrant Populations: A Narrative Review

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