Non-injecting routes of administration among entrants to three treatment modalities for heroin dependence

Relationship between opioid cross-tolerance during buprenorphine stabilization and return to opioid use during buprenorphine dose tapering

RATIONALE

Opioid injection drug use (IDU) has been linked to a more severe pattern of use (e.g. tolerance, overdose risk) and shorter retention in treatment, which may undermine abstinence attempts.

OBJECTIVES

This secondary data analysis of four human laboratory studies investigated whether current opioid IDU modulates subjective abuse liability responses to high-dose hydromorphone during intermediate-dose buprenorphine stabilization (designed to suppress withdrawal but allow surmountable agonist effects), and whether hydromorphone response magnitude predicts latency of return to opioid use during buprenorphine dose-tapering.

METHODS

Regular heroin users not currently seeking treatment (n = 54; 29 current injectors, 25 non-injectors) were stabilized on 8-mg/day sublingual buprenorphine and assessed for subjective responses (e.g. 'liking', craving) to hydromorphone 24-mg intramuscular challenge (administered 16-hr post-buprenorphine) under randomized, double-blinded, controlled conditions. A subgroup (n = 35) subsequently completed a standardized 3-week outpatient buprenorphine dose-taper, paired with opioid-abstinent contingent reinforcement, and were assessed for return to opioid use based on thrice-weekly urinalysis and self-report.

RESULTS

During buprenorphine stabilization, IDU reported lower 'liking' of buprenorphine and post-hydromorphone peak 'liking', 'good effect' and 'high' compared to non-IDU. Less hydromorphone peak increase-from-baseline in 'liking' (which correlated with less hydromorphone-induced craving suppression) predicted significantly faster return to opioid use during buprenorphine dose-tapering.

CONCLUSIONS

In these buprenorphine-stabilized regular heroin users, IDU is associated with attenuated 'liking' response (more cross-tolerance) to buprenorphine and to high-dose hydromorphone challenge and, in turn, this cross-tolerance (but not IDU) predicts faster return to opioid use. Further research should examine mechanisms that link cross-tolerance to treatment response.

Feeling safer: effectiveness, feasibility, and acceptability of continuous pulse oximetry for people who smoke opioids at overdose prevention services in British Columbia, Canada

BACKGROUND

Smoking is the most common mode of unregulated opioid consumption overall and implicated in fatal overdoses in British Columbia (BC). In part, perception of decreased risk (e.g., fewer who smoke carry naloxone kits) and limited smoking-specific harm reduction services contribute to overdose deaths. Overdose prevention services (OPS) offer supervised settings for drug use. Continuous pulse oximetry, common in acute care, allows real-time, remote oxygen monitoring. We evaluated the effectiveness of a novel continuous pulse oximetry protocol aimed at allowing physical distancing (as required by COVID-19, secluded spaces, and to avoid staff exposure to vaporized opioids), its feasibility, and acceptability at OPS for people who smoke opioids.

METHODS

This was a mixed methods survey study. We developed a continuous pulse oximetry protocol in collaboration with clinical experts and people with lived/living experience of substance use. We implemented our protocol from March to August 2021 at four OPS in BC permitting smoking. We included adults (≥ 18 years) presenting to OPS to smoke opioids. Peer researchers collected demographic, health, and substance use information, and conducted structured observations. OPS clients participating in our study, OPS staff, and peer researchers completed post-monitoring surveys. We analyzed responses using a thematic inductive approach and validated themes with peer researchers.

RESULTS

We included 599 smoking events. OPS clients participating in our study had a mean age of 38.5 years; 73% were male. Most (98%) reported using "down", heroin, or fentanyl; 48% concurrently used other substances (32% of whom reported stimulants); 76% reported smoking alone in the last 3 days; and 36% reported an overdose while smoking. Respondents reported that the protocol facilitated physical distancing, was easy to use, high satisfaction, improved confidence, improved sense of safety, and that they would use it again.

CONCLUSIONS

Continuous pulse oximetry allowed safe physical distancing, was feasible, and acceptable in monitoring people who smoke opioids at OPS.

Rats chasing the dragon: A new heroin inhalation method

BACKGROUND

Despite extensive human use of inhalation for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization.

NEW METHOD

Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration.

RESULTS

Ten minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure.

COMPARISON WITH EXISTING METHODS

Inhalation of directly volatilized heroin successfully produces heroin-typical effects, comparable to EDDS inhalation delivery.

CONCLUSIONS

This study shows that "chasing the dragon" methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into the middle age of rats.

Rats Chasing the Dragon: A new heroin inhalation method

Rationale

Despite extensive human use of the inhalation route for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization.

Objective

This study was designed to determine if direct volatilization of heroin hydrochloride delivers effective heroin doses to rodents.

Methods

Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration.

Results

Ten minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure.

Conclusions

This study shows that "chasing the dragon" methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into middle age of rat species.

Buprenorphine as a Treatment for Major Depression and Opioid Use Disorder

Rates of major depressive disorder (MDD) are disproportionally high in subjects with opioid use disorder (OUD) relative to the general population. MDD is often more severe in OUD patients, leading to compliance issues with maintenance therapies and poor outcomes. A growing body of literature suggests that endogenous opioid system dysregulation may play a role in the emergence of MDD. Buprenorphine, a mixed opioid receptor agonist/antagonist approved for the treatment of OUD and chronic pain, may have potential as a novel therapeutic for MDD, especially for patients with a dual diagnosis of MDD and OUD. This paper presents a comprehensive review of papers relevant to the assessment of buprenorphine as a treatment for MDD, OUD, and/or suicide compiled using electronic databases per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The principal goal of this literature review was to compile the clinical studies that have interrogated the antidepressant activity of buprenorphine in opioid naïve MDD patients and OUD patients with comorbid MDD. Evidence supporting buprenorphine's superiority over methadone for treating comorbid OUD and MDD was also considered. Finally, recent evidence for the ability of buprenorphine to alleviate suicidal ideation in both opioid-naïve patients and opioid-experienced patients was evaluated. Synthesizing all of this information, buprenorphine emerges as a potentially effective therapeutic for the dual purposes of treating MDD and OUD.

Treatment Outcomes Among Black Adults Receiving Medication for Opioid Use Disorder

Largely due to structural racism, Black people with substance use disorder have worse outcomes than their White counterparts. The opioid epidemic has amplified these racial disparities. Little is known about strengths that buffer against the systemic issues that disproportionately impact Black adults with opioid use disorder (OUD), particularly those receiving buprenorphine for OUD. The objectives of this study are to (1) assess psychosocial and clinical predictors of OUD outcomes and (2) explore differences in OUD outcomes by gender among a sample of Black adults receiving buprenorphine. This is a secondary data analysis of a cross-sectional survey and medical record review with a convenience sample recruited from an addiction medicine clinic. Analyses included Black participants who provided at least one urine drug test during the study period (n = 98). Prospective 6-month OUD outcomes (treatment retention, substance use recurrence, and buprenorphine continuation) were abstracted from the medical record. Univariate analyses explored differences by gender. Multivariate regressions assessed predictors of OUD outcomes. Participants were 53% women and middle-aged (47 ± 12 years). The majority (59%) had been in treatment for at least 1 year at study enrollment. Substance use recurrence was common, but many individuals remained in treatment. OUD outcomes did not differ by gender. Older age and absence of injection opioid use history were significant predictors of treatment retention and buprenorphine continuation. When provided access to high-quality treatment, Black adults with OUD demonstrate positive outcomes. Addressing structural racism and developing culturally informed treatment interventions are necessary to improve access to high-quality care for this community.

Buprenorphine: prospective novel therapy for depression and PTSD

BACKGROUND

Depression and post-traumatic stress disorder (PTSD) are leading causes of disability and loss of life by suicide. Currently, there are less than satisfactory medical solutions to treat these mental disorders. Here, we explore recent preclinical and clinical studies demonstrating the potential of using buprenorphine to treat major depressive disorder, treatment-resistant depression, and PTSD.

METHOD

Bibliographic databases were searched to include preclinical and clinical studies demonstrating the therapeutic potential of buprenorphine and the involvement of the kappa opioid receptor (KOR) in mediating these effects.

RESULTS

Original clinical studies examining the effectiveness of buprenorphine to treat depression were mixed. The majority of participants in the PTSD studies were males and suffer from chronic pain and/or substance use disorders. Nonetheless, these recent studies and analyses established proof of concept warranting farther investigations. Additionally, KOR likely mediates the antidepressant and some of the anxiolytic effects of buprenorphine. Still, it appears that the full spectrum of buprenorphine's beneficial effects might be due to activity at other opioid receptors as well.

CONCLUSIONS

Pharmaceuticals' abilities to treat medical conditions directly relates to their ability to act upon the endogenous biological systems related to the conditions. Thus, these recent findings are likely a reflection of the central role that the endogenous opioid system has in these mental illnesses. Further studies are necessary to study the involvement of endogenous opioid systems, and specifically KOR, in mediating buprenorphine's beneficial effects and the ability to treat these medical conditions while minimizing risks for misuse and diversion.

Injection opioid use as a predictor of treatment outcomes among methadone-maintained opioid-dependent patients

BACKGROUND

Injection opioid use is associated with more severe health and psychosocial consequences relative to non-injection use, but few studies have examined whether injection use is associated with methadone maintenance treatment outcomes. The present study examined differential MMT outcomes among opioid injectors and non-injectors.

METHODS

Data were extracted from the clinic charts of opioid-dependent MMT patients (N = 290; n = 115 injectors) enrolled in a university-affiliated, urban MMT clinic. Injection status was examined as a predictor of short- (3-month opioid, cocaine, benzodiazepine and cannabis urine drug screens) and long- (days retained in treatment) term MMT outcomes.

RESULTS

Bivariate analyses revealed injection users were less likely to be African American and to have completed high school, were more likely to have started heroin use before age 21, to report having hepatitis C, to report a baseline cocaine use disorder, and had higher methadone doses at 3-months into treatment. Injection status significantly predicted a greater proportion of cocaine-positive urine drug screens in the first 3 months of treatment, but did not significantly predict opioid, benzodiazepine or cannabis drug screens, or length of treatment retention.

CONCLUSION

This is one of a handful of studies to examine injection status as a predictor of MMT outcomes. Injection status is associated with cocaine use early in treatment, which has implications for the focus of treatment.

Buprenorphine/naloxone and methadone maintenance treatment outcomes for opioid analgesic, heroin, and combined users: findings from starting treatment with agonist replacement therapies (START)

OBJECTIVE

The objective of this secondary analysis was to explore differences in baseline clinical characteristics and opioid replacement therapy treatment outcomes by type (heroin, opioid analgesic [OA], or combined [heroin and OA]) and route (injector or non-injector) of opioid use.

METHOD

A total of 1,269 participants (32.2% female) were randomized to receive one of two study medications (methadone or buprenorphine/naloxone [BUP]). Of these, 731 participants completed the 24-week active medication phase. Treatment outcomes were opioid use during the final 30 days of treatment (among treatment completers) and treatment attrition.

RESULTS

Non-opioid substance dependence diagnoses and injecting differentiated heroin and combined users from OA users. Non-opioid substance dependence diagnoses and greater heroin use differentiated injectors from non-injectors. Further, injectors were more likely to be using at end of treatment compared with non-injectors. OA users were more likely to complete treatment compared with heroin users and combined users. Non-injectors were more likely than injectors to complete treatment. There were no interactions between type of opioid used or injection status and treatment assignment (methadone or BUP) on either opioid use or treatment attrition.

CONCLUSIONS

Findings indicate that substance use severity differentiates heroin users from OA users and injectors from non-injectors. Irrespective of medication, heroin use and injecting are associated with treatment attrition and opioid misuse during treatment. These results have particular clinical interest, as there is no evidence of superiority of BUP over methadone for treating OA users versus heroin users.

Retention of participants in medication-assisted programs in low- and middle-income countries: an international systematic review

BACKGROUND AND AIMS

Medication-assisted treatment (MAT) is a key component in overdose prevention, reducing illicit opiate use and risk of blood-borne virus infection. By retaining participants in MAT programs for longer periods of time, more noticeable and permanent changes in drug use, risk behavior and quality of life can be achieved. Many studies have documented retention in MAT programs in high-income countries, using a 50% average 12-month follow-up retention rate as a marker for a successful MAT program. This study contributes to a systematic understanding of how successful programs have been in retaining participants in low- and middle-income countries (LMIC) over time.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic literature search to identify MAT program studies that documented changes in retention over time for participants in buprenorphine and methadone programs in LMIC. Retention was measured for participants by length of follow-up, type of MAT and treatment dosage.

RESULTS

There were 58 MAT program studies, with 27 047 participants eligible for inclusion in the review. Overall average retention after 12 months was 54.3% [95% confidence interval (CI) = 46.2, 63.7%]. Overall average retention was moderately good for both buprenorphine (48.3%, 95% CI = 22.1, 74.6%) and methadone (56.6%, 95% CI = 45.9%, 67.3%) after 12 months of treatment. Among programs using methadone there was no statistically significant difference in average retention by dosage level, and the 10 highest and lowest dosage programs obtained similar average retention levels after 12 months.

CONCLUSION

Medication-assisted treatment programs in low- and middle-income countries achieve an average 50% retention rate after 12 months, with wide variation across programs but little difference between those using buprenorphine versus methadone.

Factors associated with history of non-fatal overdose among young nonmedical users of prescription drugs

OBJECTIVES

The current study examines the prevalence and correlates of lifetime non-fatal overdose (OD) involving the nonmedical use of prescription opioids and tranquilizers among a sample of high-risk young adults in New York, NY and Los Angeles, CA.

METHODS

Data were derived from a cross-sectional study of 16-25 year old nonmedical users of prescription drugs (n=596). Unadjusted associations between OD history and socio-demographic and drug use variables were investigated in bivariate logistic regression models. Multivariate logistic regression models identified correlates of non-fatal OD.

RESULTS

Lifetime prevalence of non-fatal overdose involving prescription opioids and/or tranquilizers was 23.6%. Factors associated with increased risk of non-fatal overdose included lower social class while growing up (OR: 1.81, 95% CI: [1.15, 2.83], p<0.01), having ever received care at a psychiatric hospital (OR: 1.79, 95% CI: [1.12, 2.85], p<0.05), ever witnessing a family member OD on drugs (OR: 1.59, 95% CI: [1.02, 2.50], p<0.05), being prescribed tranquilizers (OR: 2.07, 95% CI: [1.29, 4.27], p<0.01), ever snorting or sniffing opioids (OR: 2.51, 95% CI: [1.48, 4.27], p<0.001), injecting tranquilizers (OR: 3.09, 95% CI: [1.61, 5.93], p<0.001), and past 90-day injection drug use (OR: 1.68, 95% CI: [1.03, 2.74], p<0.05). Participants who reported past 90-day stimulant misuse had lower odds of reporting OD compared to those who were not recent stimulant users (OR: 0.60, 95% CI: [0.38-0.96], p<0.05).

CONCLUSIONS

This study documents the high prevalence of experiencing non-fatal overdose among young nonmedical users of prescription drugs. Results could inform overdose prevention efforts throughout the U.S.

Personality differences between drug injectors and non-injectors among substance-dependent patients in substitution treatment

BACKGROUND

Understanding personality differences between injectors and non-injectors in substitution treatment may provide new insights to help improve treatment programs.

OBJECTIVE

The aim of this study was to compare drug injectors and non-injectors in terms of personality disorders and dimensions.

METHODS

Forty participants recruited from substance abuse treatment centers (23 injectors and 17 non-injectors) completed the self-report Personality Diagnostic Questionnaire 4th version and Temperament and Character Inventory. Mann-Whitney U tests were used to compare means of personality disorder traits, temperament, and character differences between injectors and non-injectors.

RESULTS

The mean (SD) age of the sample (72.5% male) was 36.5 (8.7) years. Injectors reported more borderline personality disorders and increased global personality disturbance (p < .05). Similarly, Anticipatory worry, Shyness, and Fatigability facet scores were higher among injectors (p < .01). Attachment, Purposeful, and Congruent second nature facet scores were higher among non-injectors (p < .01).

CONCLUSION

According to the route of drug administration, drug dependents differed in terms of personality disorders and dimensions.

SCIENTIFIC SIGNIFICANCE

These results may have implications for the implementation of treatment programs. New research in this area may contribute to the understanding and prevention of intravenous drug use.

Non-fatal heroin overdose, treatment exposure and client characteristics: Findings from the Australian Treatment Outcome Study (ATOS)

The relationship between treatment exposure, drug use, psychosocial variables and non-fatal heroin overdose was examined among a cohort of 495 heroin users, re-interviewed at 12 months. The 12-month overdose rate declined from 24% to 12%, and the proportion administered naloxone declined from 15% to 7%. There were significant reductions in overdose among those who entered maintenance therapies (22% to 4%) and residential rehabilitation (33% vs. 19%) at baseline, but not among those who entered detoxification or were not entering treatment. The total number of treatment days received over the follow-up period was associated independently with a reduced risk of overdose. Each extra treatment day was associated with a 1% reduction in risk of overdose over the follow-up period. By contrast, more treatment episodes were associated with an increased risk of overdose (OR 1.62). Other independent predictors of overdose over follow-up were more extensive polydrug use (OR 1.40), and having overdosed in the year preceding the study (OR 7.87).

Estimating the prevalence of injection drug use among black and white adults in large U.S. metropolitan areas over time (1992--2002): estimation methods and prevalence trends

No adequate data exist on patterns of injection drug use (IDU) prevalence over time within racial/ethnic groups in U.S. geographic areas. The absence of such prevalence data limits our understanding of the causes and consequences of IDU and hampers planning efforts for IDU-related interventions. Here, we (1) describe a method of estimating IDU prevalence among non-Hispanic Black and non-Hispanic White adult residents of 95 large U.S. metropolitan statistical areas (MSAs) annually over an 11-year period (1992--2002); (2) validate the resulting prevalence estimates; and (3) document temporal trends in these prevalence estimates. IDU prevalence estimates for Black adults were calculated in several steps: we (1) created estimates of the proportion of injectors who were Black in each MSA and year by analyzing databases documenting injectors' encounters with the healthcare system; (2) multiplied the resulting proportions by previously calculated estimates of the total number of injectors in each MSA and year (Brady et al., 2008); (3) divided the result by the number of Black adults living in each MSA each year; and (4) validated the resulting estimates by correlating them cross-sectionally with theoretically related constructs (Black- and White-specific prevalences of drug-related mortality and of mortality from hepatitis C). We used parallel methods to estimate and validate White IDU prevalence. We analyzed trends in the resulting racial/ethnic-specific IDU prevalence estimates using measures of central tendency and hierarchical linear models (HLM). Black IDU prevalence declined from a median of 279 injectors per 10,000 adults in 1992 to 156 injectors per 10,000 adults in 2002. IDU prevalence for White adults remained relatively flat over time (median values ranged between 86 and 97 injectors per 10,000 adults). HLM analyses described similar trends and suggest that declines in Black IDU prevalence decelerated over time. Both sets of IDU estimates correlated cross-sectionally adequately with validators, suggesting that they have acceptable convergent validity (range for Black IDU prevalence validation: 0.27 < r < 0.61; range for White IDU prevalence: 0.38 < r < 0.80). These data give insight, for the first time, into IDU prevalence trends among Black adults and White adults in large U.S. MSAs. The decline seen here for Black adults may partially explain recent reductions in newly reported cases of IDU-related HIV evident in surveillance data on this population. Declining Black IDU prevalence may have been produced by (1) high AIDS-related mortality rates among Black injectors in the 1990s, rates lowered by the advent of HAART; (2) reduced IDU incidence among Black drug users; and/or (3) MSA-level social processes (e.g., diminishing residential segregation). The stability of IDU prevalence among White adults between 1992 and 2002 may be a function of lower AIDS-related mortality rates in this population; relative stability (and perhaps increases in some MSAs) in initiating IDU among White drug users; and social processes. Future research should investigate the extent to which these racial/ethnic-specific IDU prevalence trends (1) explain, and are explained by, recent trends in IDU-related health outcomes, and (2) are determined by MSA-level social processes.

Injecting and Noninjecting Heroin Administration: Transitions and Treatment Outcomes across 36 Months

To examine long-term stability in route of administration and treatment outcomes for noninjecting (NIHU) and injecting (IHU) heroin users, a cohort of 429 heroin users were followed over 36 months. Across follow-up, 35.3% of NIHU injected heroin and a transition to primary heroin injecting was made by 8.5%. Amongst IHU, 11.1% smoked heroin and a transition to primary heroin smoking was made by 2.3%. While NIHU were less likely to be in treatment at 36 months, there were no differences in overall treatment exposure. At 36 months, there were no differences in heroin use, polydrug use, crime, physical health, or psychopathology. NIHU were, however, less likely to be injecting and to have injection-related health problems. It is concluded that there is a substantial risk of injecting occurring amongst NIHU and that route of administration does not differentially predict long-term treatment response.

Intravenous and intranasal heroin-dependent treatment-seekers: characteristics and treatment outcome

AIMS

This study compared the characteristics of intravenous (i.v.) and intranasal (i.n.) heroin users seeking methadone treatment, and their response to treatment.

PARTICIPANTS

A total of 319 heroin-dependent adults.

DESIGN

Participants were assigned randomly to receive interim methadone treatment or to a waiting list control on a 3 : 2 basis. Analyses were conducted by dividing participants into two groups based on their route of heroin ingestion: i.v. or i.n.

SETTING

A methadone clinic in Baltimore City, Maryland.

INTERVENTION

Interim methadone treatment consisted of providing an adequate and stable dose of methadone, but no psychosocial services, to heroin-dependent adults for up to 120 days while they awaited an opening for comprehensive methadone treatment.

MEASURES

Addiction Severity Index, Texas Christian University AIDS Risk Assessment, a questionnaire on treatment entry and a urine drug test were collected at baseline and at entry into a comprehensive treatment program, or at 120 days after baseline assessment, whichever came first.

FINDINGS

At baseline, over 60% of participants were i.n. users and had been for an average of over 12 years; i.v. users, compared to i.n. users, were more likely to have ever used cocaine, to have used cocaine in the past 30 days, to have more medical complications and to report more income generated from criminal behavior. Both i.v. and i.n. users reduced their self-reported days of heroin use, cocaine use and days of criminal activity in response to interim methadone treatment.

CONCLUSIONS

Despite differences in baseline characteristics, i.n. and i.v. heroin-dependent individuals did not differ in their response to interim methadone treatment.

The Australian Treatment Outcome Study (ATOS): what have we learnt about treatment for heroin dependence?

Opioids make the single largest contribution to illicit drug-related mortality and morbidity worldwide In this paper we reflect upon what has been learnt regarding treatment outcome and the natural history of heroin use from the Australian Treatment Outcome Study (ATOS). We focus on what we knew prior to ATOS, what ATOS revealed that is novel, and the implications for research, practice and policy. ATOS provided strong evidence for sustained improvement attributable to treatment across the three years of the study. It is argued that treatment for heroin dependence is money well spent, and leads to clear and sustained benefits to both heroin users and society.

Prevalence and correlates of opiate overdose among young injection drug users in a large U.S. city

OBJECTIVES

The current study examines the prevalence and correlates of witnessing and experiencing opiate overdoses among a sample of young, injection drug users (IDUs) and non-injection drug users (NIDUs) in Baltimore, MD.

METHODS

Data were derived from a longitudinal study of 15-30 year old IDUs and NIDUs (N=309) who had initiated heroin, cocaine, and/or crack use within 5 years prior to study enrollment. Chi-square and Wilcoxon rank-sum tests were used in bivariate analyses of demographic and drug use variables with each of the two dependent variables. Multivariate logistic regression models were used to identify correlates of experiencing and witnessing overdose.

RESULTS

Twenty-nine percent of participants reported having ever experienced an opiate overdose and 57% reported having ever witnessed an overdose. Having ever experienced an opiate overdose was independently associated with being White (Adjusted Odds Ratio [AOR]=3.2; 95% Confidence Interval [CI]: 1.6, 6.4) recent homelessness (AOR=2.9; 95%CI: 1.5, 5.7); and length of injection, 5.6-6.9 years versus <5.6 years (AOR=4.0; 95%CI: 1.8-8.9); injecting 7.0-7.9 years versus <5.6 years (AOR=2.5; 95%CI: 1.03-6.1); injecting >8 versus <5.6 years (AOR=4.7; 95%CI: 2.2-10.2). Having witnessed an opiate overdose was independently associated with being White (AOR=2.4; 95%CI: 1.4, 4.1) and injecting >8 years versus <5.6 years (AOR=2.2; 95%CI: 1.2, 4.0).

CONCLUSIONS

This study documents the high prevalence of witnessing and experiencing opiate overdoses among young, newly initiated IDUs and NIDUs. The results could inform the growing number of overdose prevention efforts throughout the U.S.

'Treatment experienced' and 'treatment naïve' drug agency clients compared

BACKGROUND

Research on the prevalence and significance of previous treatment is limited, but indicates that many drug agency clients have had prior drug treatment experiences. Furthermore, treatment experienced drug users have different characteristics from treatment novices at treatment entry and poorer outcomes at follow up.

METHODS

Data from a national longitudinal study of drug users entering treatment in Scotland were analysed using univariate and multivariate techniques to provide the first systematic comparison of treatment experienced and treatment naïve drug users in the UK. Respondents (n=653) were interviewed on four separate occasions (treatment intake, 8 months, 16 months, and 33 months) using structured questionnaires.

RESULTS

Five hundred and fifty-eight individuals (85.5%) had had some form of previous treatment and many reported multiple previous treatments, most commonly substitute drugs. At treatment intake, treatment experienced respondents had worse drug use and life problems than treatment novices. Very high levels of illicit drug use (>85%) were reported by both treatment experienced and treatment naïve drug users at all follow-ups, with no significant differences between the two groups at any time point.

CONCLUSIONS

Drug users entering treatment in Scotland have routinely had multiple earlier treatments and report high levels of illicit drug use at follow up. Contrary to some earlier research, there is no evidence that those who are treatment experienced have worse drug use outcomes than those who are treatment naïve. Findings add to the international literature on prior treatment experiences and new treatment clients' needs.

Twelve-month outcomes for heroin dependence treatments: does route of administration matter?

A sample of 442 heroin users (394 injecting heroin users: IHU, 48 non-injecting heroin users: NIHU) recruited for the Australian Treatment Outcome Study were reinterviewed at 12 months after entrance to treatment for heroin dependence. Route of administration was stable over the follow-up period with 4% of NIHU having made a transition to heroin injecting, and 0.3% of IHU having made a transition to non-injecting. Given the clinical profile of NIHU presented in the literature, it might be expected that they would exhibit better treatment retention and 12-month outcomes than IHU. At 12 months, however, there were no differences between NIHU and IHU in heroin use, heroin dependence symptoms, polydrug use, criminality, current self-reported physical health or psychopathology. The only group differences at 12 months were that NIHU were more likely to be employed and had fewer injection-related problems. It is concluded that, among those presenting for treatment, route of administration is not an indicator of likely outcome.

Endogenous opiates and behavior: 2004

This paper is the 27th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over 30 years of research. It summarizes papers published during 2004 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

The medical complications of heroin use

PURPOSE OF REVIEW

Heroin use is associated with numerous adverse sequelae. As clinical services develop, addiction psychiatrists will increasingly be called upon to help identify and manage the complications of heroin use. This review focuses on recent research into the medical complications of heroin use and looks at strategies to minimize harm associated with this practice.

RECENT FINDINGS

Mortality associated with heroin overdose has increased substantially in many countries. Parenteral use of opioid drugs is a central factor and other risk factors include polydrug use, particularly benzodiazepines and alcohol, mental health issues and environmental factors not conducive to resuscitation. Unravelling the determinants of blood-borne virus transmission continues, the focus shifting from needle sharing to inadvertent sharing of other injecting equipment. Trials addressing the challenges of antiviral therapy in injecting drug users are emerging. A greater understanding of the effects of opioids on immune functioning complements our knowledge of infection in the heroin-using group as well as possibly explaining the reduced response to vaccination in this group.

SUMMARY

Medical complications of heroin affect a number of different organ systems. The role of the addiction specialist is to be aware of these so that early diagnosis and appropriate management is instituted. The latter will generally be done in collaboration with other specialists. The addictions specialist can play a significant role in the development of clinical systems to minimize these complications.