The long-term outcomes of drug use by methadone maintenance patients

Associations Between Buprenorphine\Naloxone and Methadone Treatment and non-Opioid Substance Use in Prescription-Type Opioid Use Disorder: Secondary Analyses From the OPTIMA Study: Associations entre le traitement avec la buprénorphine/naloxone et avec la méthadone et l'utilisation de substances non opioïdes dans le trouble lié à l'usage d'opioïdes de type sur ordonnance : analyses secondaires de l'étude OPTIMA

OBJECTIVES

There is limited evidence on how opioid agonist treatment (OAT) may affect psychoactive non-opioid substance use in prescription-type opioid use disorder (POUD) and whether this effect might explain OAT outcomes. We aimed to assess the effect of methadone on non-opioid substance use compared to buprenorphine/naloxone (BUP/NX), to explore whether non-opioid substance use is associated with opioid use and retention in treatment, and to test non-opioid use as a moderator of associations between methadone with retention in OAT and opioid use compared to BUP/NX.

METHODS

This is a secondary analysis of data from the OPTIMA trial, an open-label, pragmatic, parallel, two-arm, pan-Canadian, multicentre, randomized-controlled trial to compare standard methadone model of care and flexible take-home dosing BUP/NX for POUD treatment. We studied the effect of methadone and BUP/NX on non-opioid substance use evaluated by urine drug screen (UDS) and by classes of non-opioid substances (i.e., tetrahydrocannabinol [THC], benzodiazepines, stimulants) (weeks 2-24) using adjusted generalized estimation equation (GEE). We studied the association between non-opioid substance-positive UDS and opioid-positive UDS and retention in treatment, using adjusted GEE and logistic regressions.

RESULTS

Overall, methadone was not associated with non-opioid substance-positive UDS compared to BUP/NX (OR: 0.78; 95%CI, 0.41 to 1.48). When non-opioid substances were studied separately, methadone was associated with lower odds of benzodiazepine-positive UDS (OR: 0.63; 95% CI: 0.40 to 0.98) and THC-positive UDS (OR: 0.47; 95% CI: 0.28 to 0.77), but not with different odds of stimulant-positive UDS (OR: 1.29; 95% CI: 0.78 to 2.16) compared to BUP/NX. Substance-positive UDS, overall and separate classes, were not associated with opioid-positive UDS or retention in treatment.

CONCLUSION

Methadone did not show a significant effect on overall non-opioid substance use in POUD compared to BUP/NX treatment but was associated with lower odds of benzodiazepine and THC use in particular. Non-opioid substance use did not predict OAT outcomes. Further research is needed to ascertain whether specific patterns of polysubstance use (quantity and frequency) may affect treatment outcomes.

Patterns of polydrug use among Black Americans who misuse opioids

In the United States, opioid-related deaths involving polydrug use are now more prevalent than those involving only opioids. What often goes unnoticed is that deaths involving more than one substance are increasing more rapidly among Black Americans than Whites. Unfortunately, little research attention is paid to understanding opioid-related polydrug use patterns among Black Americans. As a result, less is known regarding which drug combinations are most common among this population and their reasons for co-using certain drugs. Therefore, the objective of this mixed methods study was to identify which substances were most commonly co-used with opioids among Black Americans, while also capturing their motives for combining opioids with other drugs. This study used data from the Florida Minority Health Study, a mixed-methods project that included online surveys (n = 303) and qualitative in-depth interviews (n = 30) of Black Americans who misuse opioids. Data collection was conducted from August 2021 to February 2022 throughout Southwest Florida. Analyses revealed that opioids were most commonly combined with alcohol, cocaine, and methamphetamine, respectively. Opioids were co-used with alcohol in an attempt to enhance the desired effect (i.e., intoxication), while stimulants and opioids were combined to counteract the undesirable side effects of the other. This study begins to answer the question of which/why substances are combined with opioids among Black Americans and should inform behavioral health interventions targeted at this population. Data on this topic are especially timely as the United States goes through the current fourth wave of the opioid crisis that is characterized by deaths due to polydrug use. These findings invite further study using nationally representative data to determine the extent to which polydrug using patterns differ across racial/ethnic groups.

Risks of returning to opioid use at treatment entry and early in opioid use disorder treatment: Role of non-opioid substances

OBJECTIVE

Patients in treatment with medications for opioid use disorder (MOUD) often report use of other substances in addition to opioids. Few studies exist that examine the relationship between use at treatment entry and early non-opioid use in opioid treatment outcome.

METHODOLOGY

We combined and harmonized three randomized, controlled MOUD clinical trials from the National Institutes of Drug Abuse (NIDA) Clinical Trials Network (CTN) (N=2197) and investigated the association of non-opioid substance use at treatment entry and during early treatment with a return to opioid use. The trials compared MOUD treatment (buprenorphine, methadone, extended-release naltrexone) in populations with opioid use disorder (OUD). Non-opioid substances were identified through harmonizing self-reported use. The primary outcomes were markers of return to opioid use by 12 weeks.

RESULTS

When treatment cohorts were adjusted, no association between self-reported treatment entry use of non-opioid substances and week-12 opioid use was detected. During the first month of treatment, higher use of cocaine (OR 1.41 [1.18-1.69]) and amphetamine (OR 1.70 [1.27-2.26]) was found to be associated with higher likelihood of illicit opioid use by week 12. Exploratory analyses of potential treatment cohort-by-predictor interactions showed that those with heavier cocaine use had a lower rate of returning to opioid use in the extended-release naltrexone group than in the methadone group.

CONCLUSION

Substance use other than opioids at treatment entry is not associated with relapse. Use of cocaine or amphetamines during the first few weeks of MOUD treatment may signal a worse outcome, suggesting a need for additional interventions.

The effect of concurrent access to alcohol and oxycodone on self-administration and reinstatement in rats

RATIONALE

Although polysubstance use is highly prevalent, preclinical studies that assess voluntary consumption of multiple substances at the same time are rather uncommon. Overlooking drug taking patterns commonly observed in humans may limit the translational value of preclinical models.

OBJECTIVES

Here, we aimed to develop a model of polysubstance use that could be used to assess oral operant self-administration patterns under concurrent access to alcohol and the prescription opioid oxycodone.

METHODS

After a training period where animals associated specific cues and levers with each drug, rats self-administered alcohol and oxycodone solutions concurrently in daily sessions. Oxycodone was then removed to assess potential changes in alcohol consumption. The role of cues and stress on alcohol consumption and oxycodone seeking was also examined under reinstatement conditions.

RESULTS

We found that females consumed more alcohol and oxycodone than males when given access to both drugs, and this effect on alcohol intake persisted when oxycodone was removed. Additionally, re-exposure to oxycodone cues in combination with the administration of the pharmacological stressor yohimbine drove reinstatement of oxycodone seeking in females but did not have a strong effect in males, possibly due to low levels of oxycodone intake during active self-administration in male rats. Additionally, yohimbine drove increased alcohol consumption, in line with prior findings from our group and others.

CONCLUSIONS

Taken together, this study demonstrates that rats will concurrently self-administer both oxycodone and alcohol in operant chambers, and this procedure can serve as a platform for future investigations in polysubstance use and relapse-like behavior.

Addressing injecting related risks among people who inject both opioids and stimulants: Findings from an Australian survey of people who inject drugs

Background

Opioids and stimulants are the most commonly injected illicit drugs worldwide and in Australia. While some people who inject drugs (PWID) prefer either opioids or stimulants, others regularly use both opioids and stimulants. Limited available research indicates that those who use opioids and stimulants together, either in combination or alternating between the two, may engage in injection-related practices which potentially place them at greater health risk and could lead to poorer health outcomes.

Methods

Participants were recruited nationally through member organizations of the Australian Injecting and Illicit Drug Users League (AIVL); these organizations represent PWID in each Australian state and territory. This study compared a sample of PWID (N = 535) who reported past-month injection of opioids only (N = 173), stimulants only (N = 208), or both (N = 154) on a range of health and wellbeing outcomes. PWID completed a survey assessing drugs injected, frequency of injecting, receptive equipment sharing, psychological distress, self-reported hepatitis C (HCV) status, experienced and internalized stigma, drug use salience, and community attachment.

Results

People who injected both opioids and stimulants reported more frequent injecting, more experiences of stigma, and greater reported HCV diagnosis than people who injected stimulants or opioids alone. They also showed greater attachment to a community of PWID and greater salience of drug use to their identity.

Conclusions

The findings of increased injecting and broader harms associated with injecting both stimulants and opioids are important for tailoring harm reduction and intervention designs for people who use both opioid and stimulant drugs, including prioritizing peer-based approaches.

Naturalistic follow-up after a trial of medications for opioid use disorder: Medication status, opioid use, and relapse

AIM

This report examined naturalistic opioid use outcomes and utilization of medications for opioid use disorder (MOUD) 36 weeks post-randomization in the National Drug Abuse Treatment Clinical Trials Network (CTN) Extended-Release Naltrexone (XR-NTX) versus Buprenorphine-Naloxone (BUP-NX) for Opioid Treatment trial (CTN-0051, X:BOT).

DESIGN

X:BOT was a multisite, randomized, 24-week comparative effectiveness trial of BUP-NX (N = 287) and XR-NTX (N = 283). Study medications were discontinued following treatment completion, relapse, or dropout. Participants were encouraged to continue MOUD. This report examined opioid use outcomes in 428 (75%) of the 570 participants who attended the 36-week follow-up visit.

SETTING AND PARTICIPANTS

Adults with opioid use disorder recruited from 8 community treatment programs across the United States.

MEASUREMENTS

Outcomes included medication status (on/off MOUD), type of MOUD (BUP-NX, XR-NTX, or methadone), abstinence from non-prescribed opioids, opioid use days, relapse, and other substance use 30 days prior to the 36-week visit. Relapse was defined as opioid use for 4 consecutive weeks or 7 consecutive days in the past month. Baseline and clinical variables included opioid use severity, intravenous drug use, study medication assignment, and induction status.

FINDINGS

Of the 428 participants who completed the 36-week visit, 225 (53%) of participants were receiving MOUD and 203 (47%) were not. Compared to those off medication, participants on medication had fewer opioid use days (4.4 days (SD 9.0) versus 9.8 days (SD 12.1)), fewer met relapse criteria (37 (16.4%) versus 79 (38.9%)), and reported less stimulant use (34 (15.2%) versus 56 (27.7%)) and sedative use (14 (6.3%) versus 31 (15.3%)). There was no difference in abstinence rates between those on or off MOUD. A greater proportion of participants on XR-NTX (47 (53.4%) of 88 participants) were abstinent from non-prescribed opioids compared to those on buprenorphine (28 (23.3%) of 120 participants).

CONCLUSIONS

Naturalistic outcomes data showed that despite potential barriers to continuing treatment in the community, about half of individuals were on opioid use disorder pharmacotherapy at follow-up and those on medication generally had better outcomes. Future research should explore barriers and facilitators to treatment retention in community settings; and developing interventions tailored to improve treatment engagement and adherence.

A cohort study evaluating the association between concurrent mental disorders, mortality, morbidity, and continuous treatment retention for patients in opioid agonist treatment (OAT) across Ontario, Canada, using administrative health data

Background

Due to the high prevalence of mental disorders among people with opioid use disorder, the objective of this study was to determine the association between concurrent mental disorders, mortality, morbidity, and continuous treatment retention for patients in opioid agonist treatment in Ontario, Canada.

Methods

We conducted a retrospective cohort study of patients enrolled in opioid agonist treatment between January 1, 2011, and December 31, 2015. Patients were stratified into two groups: those diagnosed with concurrent mental disorders and opioid use disorder and those with opioid use disorder only, using data from the Ontario Health Insurance Plan Database, Ontario Drug Benefit Plan Database. The primary outcome studied was all-cause mortality using data from the Registered Persons Database. Emergency department visits from the National Ambulatory Care Database, hospitalizations Discharge Abstract Database, and continuous retention in treatment, defined as 1 year of uninterrupted opioid agonist treatment using data from the Ontario Drug Benefit Plan Database were measured as secondary outcomes. Encrypted patient identifiers were used to link information across databases.

Results

We identified 55,924 individuals enrolled in opioid agonist treatment, and 87% had a concurrent mental disorder diagnosis during this period. We observed that having a mental disorder was associated with an increased likelihood of all-cause mortality (odds ratio (OR) 1.4; 95% confidence interval (CI) 1.2–1.5). For patients diagnosed with mental disorders, the estimated rate of ED visits per year was 2.25 times higher and estimated rate of hospitalization per year was 1.67 times higher than for patients with no mental disorders. However, there was no association between having a diagnosis of a mental disorder and 1-year treatment retention in OAT-adjusted hazard ratio (HR) = 1.0; 95% CI 0.9 to 1.1.

Conclusion

Our findings highlight the consequences of the high prevalence of mental disorders for individuals with opioid use disorder in Ontario, Canada.

Motivations for crystal methamphetamine-opioid co-injection/co-use amongst community-recruited people who inject drugs: a qualitative study

Aims

We report on motivations for crystal methamphetamine-opioid co-use/co-injection through narratives of people who inject drugs during a period of increased crystal methamphetamine use reporting in Australia.

Methods

Fourteen in-depth interviews were undertaken with selected participants (12 male, 2 female) from the Melbourne Injecting Drug User Cohort Study, including those in and out of opioid substitution therapy (OST).

Results

The main motivations for co-use reported by participants were as follows: (1) that heroin could be used to reduce the negative side effects of heavy crystal methamphetamine use, particularly during the ‘comedown’ phase; (2) that small quantities of crystal methamphetamine used with heroin could prolong the intoxication effect of heroin, and hence the time before opioid withdrawal; (3) that co-injection of crystal methamphetamine and heroin produced a more desirable intoxication effect than using either substance on its own and; (4) that crystal methamphetamine provided a substitute ‘high’ for heroin after commencing OST treatment.

Conclusions

Co-use of methamphetamine and opioids has been used by people who inject drugs to facilitate intoxication, sometimes as the result of ineffective opioid substitution therapy (OST) treatment and perceived lack of pleasure after stabilisation on OST treatment.

Multiple substance use among patients attending treatment for substance-related problems in Switzerland

Purpose

The purpose of this paper is to estimate the share of multiple substance disorders among clients entering treatment for substance-related problems, to identify the most frequent combinations of the substances involved and to investigate the profiles of the clients involved.

Design/methodology/approach

Data were taken from the Swiss treatment monitoring system act-info applied among inpatient and outpatient facilities (reporting years 2013–2015). All cases with information on multiple substance disorders, according to a definition close to the diagnosis F19 from the ICD-10 classification of disease were included. The measurements comprised designated primary substance, existing multiple substance use disorder, substances involved and basic socio-demographics.

Findings

From 10,009 clients included in the study, 1,653 (16.5 per cent) were reported as having multiple substance use disorders. A great variety of substance combinations was identified and alcohol was found in the majority of them.

Practical implications

Treatment strategies targeting accurately substance-related disorders as a whole complex should be promoted. In particular the alcohol-related aspect of the disorder should not be neglected when the focus is on illegal drugs.

Originality/value

Multiple substance use was until recently not sufficiently documented in treatment monitoring systems. A recent version of the European treatment demand indicator (TDI) has introduced the notion of “polydrug use problem” as complementary information to the primary substance, which remains the key variable for reporting treatment demand. This study represents a first attempt to explore systematically this new data.

Polydrug use and its association with drug treatment outcomes among primary heroin, methamphetamine, and cocaine users

BACKGROUND

Polydrug use may challenge effective treatment for substance use disorders. We evaluate whether secondary substance use modifies the association between treatment and primary drug use among primary heroin, cocaine and methamphetamine (MA) users.

METHODS

Data were obtained from prospective cohort studies on people who use illicit drugs (PWUD) in California, USA. Using repeated monthly data on self-reported secondary substance use (heroin, cocaine, MA, alcohol or marijuana; ≥1day in a month), primary drug use (≥1day in a month), and treatment participation, collected via timeline follow-back, we fitted generalized linear mixed multiple regression models controlling for potential confounders to examine the interactions between treatment and secondary substance use on the odds of primary heroin, cocaine and MA use, respectively.

RESULTS

Included in our study were 587 primary heroin, 444 primary MA, and 501 primary cocaine users, with a median of 32.4, 13.3 and 18.9 years of follow-up, respectively. In the absence of secondary substance use, treatment was strongly associated with decreased odds of primary drug use (adjusted odds ratios (aORs): 0.25, 95% CI: 0.24, 0.27, 0.07 (0.06, 0.08), and 0.07 (0.07, 0.09)) for primary heroin, MA, and cocaine users, respectively. Secondary substance use of any kind moderated these associations (0.82 (0.78, 0.87), 0.25 (0.21, 0.30) and 0.53 (0.45, 0.61), respectively), and these findings were consistent for each type of secondary substance considered. Moreover, we observed different associations in terms of direction and magnitude between secondary substance use and primary drug use during off-treatment periods across substance types.

CONCLUSION

This study demonstrates secondary substance use moderates the temporal associations between treatment and primary drug use among primary heroin, MA and cocaine users. Disparate patterns of polydrug use require careful measurement and analysis to inform targeted treatment for polydrug users.

Large variation in measures used to assess outcomes of opioid dependence treatment: A systematic review of longitudinal observational studies

ISSUES

Treatment outcomes for drug users are critical for informing policy and therapeutic practice. The coherence of outcomes, changes and drug use measures from observational studies on opioid use treatment were reviewed.

APPROACH

Systematic review of the literature for longitudinal observational studies, from 1980 through November 2015, in all languages, with data on treated opioid users, using Pubmed, the Cochrane Library and additional strategies (e.g. Pubmed function 'related citations' and checking reference lists of eligible studies).

KEY FINDINGS

Twenty-seven studies were included (11 countries, 85 publications, recruitment 1962-2009). Baseline n was >65 686 and median follow-up 34.5 months (21 studies) or 51.4 person-months (10 studies). Eight outcome domains were identified: 'drug use' (21/27 studies), 'crime' (13), 'health' (13), 'treatment-related' outcomes (16), 'social functioning' (13), 'harms' (8), 'mortality' (13) and 'economic estimates' (2 studies). All studies using drug use outcomes included a binary (abstinence) category in at least one measure. Studies typically reported outcomes on less than half (on average 3.7 or 46%) of the eight outcome domains, while the average was 5.1 (64%) in seven studies initiated since 2000.

IMPLICATIONS AND CONCLUSION

Wide variation exists in outcome measures found in longitudinal observational studies of treatment of opioid users. This reduces replicability of studies and suggests a lack of common expectations on treatment success. Future studies should consider using all or most of eight outcome domains identified (excluding economic analyses if unfeasible), non-binary measures and amount/value of drugs used and consensus meetings with joint ownership of scientific, treatment and patient communities.

Long-term outcomes after randomization to buprenorphine/naloxone versus methadone in a multi-site trial

AIMS

To compare long-term outcomes among participants randomized to buprenorphine or methadone.

DESIGN, SETTING AND PARTICIPANTS

Follow-up was conducted in 2011-14 of 1080 opioid-dependent participants entering seven opioid treatment programs in the United States between 2006 and 2009 and randomized (within each program) to receive open-label buprenorphine/naloxone or methadone for up to 24 weeks; 795 participants completed in-person interviews (~74% follow-up interview rate) covering on average 4.5 years.

MEASUREMENTS

Outcomes were indicated by mortality and opioid use. Covariates included demographics, site, cocaine use and treatment experiences.

FINDINGS

Mortality was not different between the two randomized conditions, with 23 (3.6%) of 630 participants randomized to buprenorphine having died versus 26 (5.8%) of 450 participants randomized to methadone. Opioid use at follow-up was higher among participants randomized to buprenorphine relative to methadone [42.8 versus 31.7% positive opioid urine specimens, P < 0.01, effect size (h) = 0.23 (0.09, 0.38); 5.8 days versus 4.4 days of past 30-day heroin use, P < 0.05, effect size (d) = 0.14 (0.00, 0.28)]. Opioid use during the follow-up period by randomization condition was also significant (F(7,39,600) = 3.16; P < 0.001) due mainly to less treatment participation among participants randomized to buprenorphine than methadone. Less opioid use was associated with both buprenorphine and methadone treatment (relative to no treatment); no difference was found between the two treatments. Individuals who are white or used cocaine at baseline responded better to methadone than to buprenorphine.

CONCLUSIONS

There are few differences in long-term outcomes between buprenorphine and methadone treatment for opioid dependence, and treatment with each medication is associated with a strong reduction in opioid use.

Patterns of use of other drugs among those with alcohol dependence: Associations with drinking behavior and psychopathology

INTRODUCTION

Alcohol dependence (AD) presents with substantial clinical heterogeneity, including concurrent use of non-alcohol drugs. Here, we examine specific patterns of concurrent non-alcohol substance use during the previous year among a nationally representative sample of adults with DSM-IV AD, and estimate their population prevalence in the U.S. We then evaluate alcohol use behavior and comorbid psychopathology among respondents with AD according to their patterns of concurrent non-alcohol substance use.

METHODS

These analyses utilized data from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Latent class analyses classified respondents with AD into four clinically meaningful patterns of concurrent substance use: (1) use of alcohol only; (2) use of alcohol and tobacco only; (3) use of alcohol, tobacco and cannabis; and (4) use of alcohol, tobacco, cannabis, cocaine, and other illicit drug(s).

RESULTS

Among AD respondents, the most prevalent pattern was the use of alcohol and tobacco only (weighted percentage, 32.4%), followed by the use of alcohol only (weighted percentage, 27.5%). AD respondents who used alcohol, tobacco, cannabis, cocaine, and other illicit drug(s) (weighted percentage, 25.3%) manifested the most severe pattern of alcohol consumption, and had significant overrepresentations of major depression, panic, and other anxiety disorders as well as paranoid, schizotypal, borderline, antisocial, and histrionic personality disorders compared with those who used alcohol alone.

CONCLUSIONS

Specific patterns of concurrent substance use convey important information regarding the clinical presentation and prognosis for AD. In particular, concurrent use of illicit drugs over the past year by AD individuals was associated with greater severity and comorbid psychopathology. These data suggest the need for pragmatic trials of AD interventions that take into account patterns of substance use behavior in addition to an AD diagnosis.

Dynamics in the costs of criminality among opioid dependent individuals

BACKGROUND

Research into the avoided crime-related costs associated with methadone maintenance treatment (MMT) is sparse. Our objective was to characterize the dynamics in crime-related costs associated with MMT effectiveness among opioid dependent individuals in Vancouver, Canada.

METHODS

We considered individuals enrolled in a prospective study between December, 2011 and May, 2013. Monthly crime-related costs (2013 CAD) were derived from self-reported criminal activity. On the basis of MMT receipt and illicit opioid use, individuals were classified in mutually exclusive health states: (i) MMT high effectiveness; (ii) MMT low effectiveness; (iii) opioid abstinence; or (iv) relapse. We classified individuals as daily, non-daily or non-stimulant users and controlled for demographic and socio-economic characteristics. A two-part multiple regression model was constructed; the first part modeled non-zero cost probability, the second estimated the level of costs. Avoided costs were estimated for each health state and stratified by stimulant use intensity.

RESULTS

Our study included 982 individuals (median age 47, 38% female) for 2232 observations. Individuals on MMT with high effectiveness incurred lower monthly costs of criminality (avoided costs of $6298; 95% C.I. ($1578, $11,017)), as did opioid abstinent individuals ($6563 ($1564, $11,561)). Avoided costs for daily stimulant users were greater than for non-daily users, both for individuals on MMT with high effectiveness ($12,975 vs. $4125) and opioid abstinent ($12,640 vs. $4814).

CONCLUSION

Using longitudinal data on individuals with a history of MMT, we found substantially lower costs of criminality associated with high effect to MMT. Avoided costs were highest among daily stimulant users that were on MMT with high effectiveness or those opioid abstinent.

Characterizing longitudinal health state transitions among heroin, cocaine, and methamphetamine users

AIMS

Characterize longitudinal patterns of drug use careers and identify determinants of drug use frequency across cohorts of primary heroin, methamphetamine (MA) and cocaine users.

DESIGN

Pooled analysis of prospective cohort studies.

SETTINGS

Illicit drug users recruited from community, criminal justice and drug treatment settings in California, USA.

PARTICIPANTS

We used longitudinal data on from five observational cohort studies featuring primary users of heroin (N=629), cocaine (N=694) and methamphetamine (N=474). The mean duration of follow-up was 20.9 years.

MEASUREMENTS

Monthly longitudinal data was arranged according to five health states (incarceration, drug treatment, abstinence, non-daily and daily use). We fitted proportional hazards (PH) frailty models to determine independent differences in successive episode durations. We then executed multi-state Markov (MSM) models to estimate probabilities of transitioning between health states, and the determinants of these transitions.

FINDINGS

Across primary drug use types, PH frailty models demonstrated durations of daily use diminished in successive episodes over time. MSM models revealed primary stimulant users had more erratic longitudinal patterns of drug use, transitioning more rapidly between periods of treatment, abstinence, non-daily and daily use. MA users exhibited relatively longer durations of high-frequency use. Criminal engagement had a destabilizing effect on health state durations across drug types. Longer incarceration histories were associated with delayed transitions toward cessation.

CONCLUSIONS

PH frailty and MSM modeling techniques provided complementary information on longitudinal patterns of drug abuse. This information can inform clinical practice and policy, and otherwise be used in health economic simulation models, designed to inform resource allocation decisions.

ANKK1 and DRD2 pharmacogenetics of disulfiram treatment for cocaine abuse

OBJECTIVE

Disulfiram is a potential cocaine addiction pharmacotherapy. Since dopamine deficiency has been found with cocaine addiction, our objective was to examine whether functional variants in the ankyrin repeat and kinase domain-containing 1 (ANKK1) and/or the dopamine receptor D2 (DRD2) genes interact with response to treatment with disulfiram.

MATERIALS AND METHODS

Cocaine and opioid codependent (DSM-IV) patients were stabilized on methadone and subsequently randomized into treatment groups - disulfiram (250 mg/day, N=31) or placebo (N=37). They were genotyped for ANKK1 (rs1800497) and DRD2 (rs2283265) polymorphisms, and the data were evaluated for an association between a cocaine-free state, as assessed by cocaine-free urine samples, and disulfiram treatment. Data were analyzed using repeated measures analysis of variance corrected for population structure.

RESULTS

Patients with CT or TT ANKK1 genotypes dropped from 80 to 52% cocaine-positive urines on disulfiram (N=13; P≤0.0001), whereas those on placebo (N=20) showed no treatment effect. Patients carrying the CC ANKK1 genotype showed no effect on treatment with disulfiram (N=18) or placebo (N=17). The GT/TT DRD2 genotype group showed a significant decrease in the number of cocaine-positive urine samples on disulfiram (N=9; 67-48%; P ≤ 0.0001), whereas the GG DRD2 genotype group showed only a marginal decrease (N=23; 84-63%; P=0.04). Genotype pattern analysis revealed that individuals carrying at least one minor allele in either gene responded better to disulfiram treatment (N=13; P ≤ 0.0001) compared with individuals carrying only the major alleles (N=17).

CONCLUSION

A patient's genotype for ANKK1, DRD2, or both, may be used to identify individuals for whom disulfiram may be an effective pharmacotherapy for cocaine dependence.

Association between gene variants and response to buprenorphine maintenance treatment

A variety of studies were addressed to differentiate responders and non-responders to substitution treatment among heroin dependent patients, without conclusive findings. In particular, preliminary pharmacogenetic findings have been reported to predict treatment effectiveness in mental health and substance use disorders. Aim of the present study was to investigate the possible association of buprenorphine (BUP) treatment outcome with gene variants that may affect kappa-opioid receptors and dopamine system function. One hundred and seven heroin addicts (West European, Caucasians) who underwent buprenorphine maintenance treatment were genotyped and classified into two groups (A and B) on the basis of treatment outcome. Non-responders to buprenorphine (group B) have been identified taking into account early drop out, continuous use of heroin, severe behavioral or psychiatric problems, misbehavior and diversion during the 6 months treatment period. No difference was evidenced between responders and non-responders to BUP in the frequency of kappa opioid receptor (OPRK1) 36G>T SNP. The frequency of dopamine transporter (DAT) gene polymorphism (SLC6A3/DAT1), allele 10, was evidently much higher in "non-responder" than in "responder" individuals (64.9% vs. 55.93%) whereas the frequency of the category of other alleles (6, 7 and 11) was higher in responder than in non-responder individuals (11.02% vs. 2.13% respectively). On one hand, the hypothesis that possible gene-related changes in kappa-opioid receptor could consistently affect buprenorphine pharmacological action and clinical effectiveness was not confirmed in our study, at least in relation to the single nucleotide polymorphism 36G>T. On the other hand, the possibility that gene-related dopamine changes could have reduced BUP effectiveness and impaired maintenance treatment outcome was cautiously supported by our findings. DAT1 gene variants such as allele 10, previously reported in association with personality and behavioral problems, would have influenced the effects of BUP-induced dopamine release, modulated through mu and kappa opioid receptors, and probably the related reinforcing capacity of the drug.

Pharmacogenetic randomized trial for cocaine abuse: disulfiram and α1A-adrenoceptor gene variation

Disulfiram is a cocaine addiction pharmacotherapy that inhibits dopamine β-hydroxylase (DβH) and reduces norepinephrine production. We examined whether a functional variant of the ADRA1A gene (Cys to Arg at codon 347 in exon 2, Cys347Arg) may enhance treatment response through decreased stimulation of this α1A-adrenoceptor, since antagonists of this receptor show promise in reducing cocaine use. Sixty-nine cocaine and opioid co-dependent (DSM-IV) subjects were stabilized on methadone for two weeks and subsequently randomized into disulfiram (250 mg/day, N=32) and placebo groups (N=37) for 10 weeks. We genotyped the ADRA1A gene polymorphism (rs1048101) and evaluated its role for increasing cocaine free urines in those subjects treated with disulfiram using repeated measures analysis of variance, corrected for population structure. The 47 patients who carried at least one T allele of rs1048101 (TT or TC genotype) reduced their cocaine positive urines from 84% to 56% on disulfiram (p=0.0001), while the 22 patients with the major allele CC genotype showed no disulfiram effect. This study indicates that a patient's ADRA1A genotype could be used to identify a subset of individuals for which disulfiram and, perhaps, other α1-adrenoceptor blockers may be an effective pharmacotherapy for cocaine dependence.

Buprenorphine treatment outcomes among opioid-dependent cocaine users and non-users

BACKGROUND AND OBJECTIVES

National treatment guidelines state that polysubstance users, including cocaine users, may not be appropriate candidates for office-based buprenorphine treatment. However, data to support this recommendation are sparse and conflicting, and the implications of this recommendation may include limiting the usefulness of buprenorphine treatment, as cocaine use is common among opioid-dependent individuals seeking buprenorphine treatment. We compared buprenorphine treatment outcomes (6-month treatment retention and self-reported opioid use over 6 months) in opioid-dependent cocaine users versus non-users who initiated buprenorphine treatment at an urban community health center.

METHODS

We followed 87 participants over 6 months, collecting interview and medical record data. We used logistic regression models to test whether baseline cocaine use was associated with treatment retention and mixed effects nonlinear models to test whether baseline cocaine use was associated with self-reported opioid use.

RESULTS

At baseline, 39.1% reported cocaine use. In all participants, self-reported opioid use decreased from 89.7% to 27.4% over 6 months, and 6-month treatment retention was 54.5%. We found no significant difference in 6-month treatment retention (AOR = 1.56, 95% CI: .58-4.17, p = .38) or self-reported opioid use (AOR = .89, 95% CI: .26-3.07, p = .85) between cocaine users and non-users.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

This study demonstrates that buprenorphine treatment retention is not worse in cocaine users than non-users, with clinically meaningful improvements in self-reported opioid use. These findings suggest that opioid-dependent cocaine users attain considerable benefits from office-based buprenorphine treatment and argue for the inclusion of these patients in office-based buprenorphine treatment programs.

Pharmacogenetic randomized trial for cocaine abuse: disulfiram and dopamine β-hydroxylase

BACKGROUND

Disulfiram has been an effective cocaine addiction pharmacotherapy, and one of its possible mechanisms of efficacy is through copper chelation and inhibition of an enzyme involved in catecholamine metabolism, dopamine β-hydroxylase (DβH), which converts dopamine to norepinephrine. A variant in the gene encoding DβH leads to reduced DβH activity, and as such, disulfiram might not be an effective treatment of cocaine dependence for individuals with this variant. This study explored that potential matching.

METHODS

Seventy-four cocaine- and opioid-codependent (DSM-V) subjects were stabilized on methadone for 2 weeks and subsequently randomized into disulfiram (250 mg/day, n = 34) and placebo groups (n = 40) for 10 weeks. We genotyped the DBH gene polymorphism, -1021C/T (rs1611115), that reduces DβH enzyme levels and evaluated its role for increasing cocaine free urines with disulfiram.

RESULTS

With repeated measures analysis of variance, corrected for population structure, disulfiram pharmacotherapy reduced cocaine-positive urines from 80% to 62% (p = .0001), and this disulfiram efficacy differed by DBH genotype group. Patients with the normal DβH level genotype dropped from 84% to 56% on disulfiram (p = .0001), whereas those with the low DBH level genotype showed no disulfiram effect.

CONCLUSIONS

This study indicates that the DBH genotype of a patient could be used to identify a subset of individuals for which disulfiram treatment might be an effective pharmacotherapy for cocaine dependence.

A randomized, controlled, pilot trial of methylphenidate and cognitive-behavioral group therapy for cocaine dependence in heroin prescription

Cocaine dependence has proved difficult to treat, whether it occurs alone or in combination with opiate dependence. No intervention has been demonstrated to be uniquely effective. Patients might benefit most from combined pharmacotherapeutic and psychotherapeutic interventions. The present study sought to evaluate the feasibility, tolerability, and efficacy of methylphenidate (MP) and cognitive-behavioral group therapy (CBGT) for cocaine dependence in diacetylmorphine-maintained patients. Sixty-two cocaine-dependent diacetylmorphine-maintained patients participated in a dual-site, double-blind, placebo-controlled pilot trial with 4 treatment conditions. The participants were randomly assigned to receive MP or a placebo each combined with either CBGT or treatment as usual for 12 weeks. Methylphenidate 30 mg and a placebo in identical capsules were administered onsite twice daily under supervision in a fixed-dose regimen without titration. Manual-guided CBGT consisted of 12 weekly sessions. Participation in the CBGT sessions was voluntary. Primary outcome measures were retention in pharmacologic treatment, cocaine-free urine samples, self-reported cocaine use, and adverse effects. Urine screens were performed thrice weekly. Seventy-one percent of the participants completed the study protocol. Methylphenidate was well tolerated with similar retention rates compared with the placebo. No serious adverse effects occurred. No difference in cocaine-free urine screens was found across the 4 treatment groups. Self-reported cocaine use was reduced in all 4 study groups. Methylphenidate and CBGT did not provide an advantage over a placebo or treatment as usual in reducing cocaine use. There were no signs of additive benefits of MP and CBGT. Because of the small sample size, the results are preliminary.

Cost-effectiveness of diacetylmorphine versus methadone for chronic opioid dependence refractory to treatment

BACKGROUND

Although diacetylmorphine has been proven to be more effective than methadone maintenance treatment for opioid dependence, its direct costs are higher. We compared the cost-effectiveness of diacetylmorphine and methadone maintenance treatment for chronic opioid dependence refractory to treatment.

METHODS

We constructed a semi-Markov cohort model using data from the North American Opiate Medication Initiative trial, supplemented with administrative data for the province of British Columbia and other published data, to capture the chronic, recurrent nature of opioid dependence. We calculated incremental cost-effectiveness ratios to compare diacetylmorphine and methadone over 1-, 5-, 10-year and lifetime horizons.

RESULTS

Diacetylmorphine was found to be a dominant strategy over methadone maintenance treatment in each of the time horizons. Over a lifetime horizon, our model showed that people receiving methadone gained 7.46 discounted quality-adjusted life-years (QALYs) on average (95% credibility interval [CI] 6.91-8.01) and generated a societal cost of $1.14 million (95% CI $736,800-$1.78 million). Those who received diacetylmorphine gained 7.92 discounted QALYs on average (95% CI 7.32-8.53) and generated a societal cost of $1.10 million (95% CI $724,100-$1.71 million). Cost savings in the diacetylmorphine cohort were realized primarily because of reductions in the costs related to criminal activity. Probabilistic sensitivity analysis showed that the probability of diacetylmorphine being cost-effective at a willingness-to-pay threshold of $0 per QALY gained was 76%; the probability was 95% at a threshold of $100,000 per QALY gained. Results were confirmed over a range of sensitivity analyses.

INTERPRETATION

Using mathematical modelling to extrapolate results from the North American Opiate Medication Initiative, we found that diacetylmorphine may be more effective and less costly than methadone among people with chronic opioid dependence refractory to treatment.

Randomized, double blind, placebo-controlled trial of disulfiram for the treatment of cocaine dependence in methadone-stabilized patients

This study examined the dose-related efficacy of disulfiram for treating cocaine dependence in methadone-stabilized cocaine dependent participants.

DESIGN

One hundred and sixty-one cocaine- and opioid-dependent volunteers were entered into a 14-week, double blind, randomized, placebo-controlled clinical trial at two sites.

METHODS

Participants were stabilized on methadone during weeks 1-2 and received disulfiram at 0, 62.5, 125 or 250 mg/day during weeks 3-14. All participants also received weekly cognitive behavioral therapy. Thrice-weekly urine samples and weekly self-reported drug use assessments were obtained.

RESULTS

Baseline subject characteristics, retention and drug use did not differ across groups. Outcome analyses were performed on those who participated beyond week 2. Opioid-positive urine samples and self-reported opioid use did not differ by treatment group. The prevalence of alcohol use was low prior to and during the trial and did not differ by treatment group. Cocaine-positive urines increased over time in the 62.5 and 125 mg disulfiram groups and decreased over time in the 250 mg disulfiram and placebo groups (p < 0.0001). Self-reported cocaine use increased in the 125 mg disulfiram group relative to the other three treatment groups (p = 0.04).

CONCLUSIONS

Disulfiram may be contraindicated for cocaine dependence at doses <250 mg/day. Whether disulfiram at higher doses is efficacious in reducing cocaine use in dually cocaine and opioid dependent individuals needs to be determined.

Does concurrent cocaine use compromise 1-year treatment outcomes for opiate users?

The current study aimed to determine whether cocaine use compromises treatment outcomes for opiate users. Data were collected from 404 opiate users at treatment intake and 1-year follow-up as part of a national treatment outcome study. Because of higher intake measures, cocaine users improved in more outcomes than nonusers, but comparisons between groups found that cocaine users had more coexisting problems. Regression analysis revealed that those who used cocaine at intake were more likely to use cocaine at 1-year follow-up, to commit crime, and to be homeless. It is concluded that treatment for opiate use "works" even in the presence of concurrent cocaine use.

Proportional hazards frailty models for recurrent methadone maintenance treatment

The authors' objective in this study was to identify determinants of time to discontinuation of methadone maintenance treatment (MMT) across multiple treatment episodes. Population-level data on drug dispensations for all patients receiving methadone for opioid maintenance throughout the tenure of the British Columbia, Canada, methadone program to date (1996-2007) were extracted from an administrative database. Proportional hazards frailty models were developed to assess factors associated with time to discontinuation from recurrent MMT episodes. A total of 17,005 patients experienced 32,656 treatment episodes over the 11-year follow-up period. Age, medical comorbidity, and physician patient load, as well as neighborhood-level socioeconomic status indicators, were significant predictors of time to discontinuation of treatment; treatment adherence and average daily doses up to and above 120 mg per day were also associated with longer treatment episodes. Studies have shown that while successfully retained in MMT, clients decrease their illicit drug use and criminal activity, and their risk of mortality is substantially lower; however, the majority of clients relapse. Many reenter treatment. The primary finding of this study was that patients experiencing multiple treatment episodes tended to stay in treatment for progressively longer periods in later episodes.

Polydrug use and implications for longitudinal research: ten-year trajectories for heroin, cocaine, and methamphetamine users

A typical approach to categorizing substance users for epidemiologic purposes or to identify substance use problems at treatment admission is by indicating the primary substance used and/or for which treatment is sought. But does such singular focus on the primary drug limit the validity of conclusions from longitudinal analysis of drug use patterns over time? This analysis combined data from five longitudinal studies conducted in California and examined 10-year patterns of heroin, cocaine, methamphetamine (meth), marijuana, and alcohol use for primary users of heroin (n=629), cocaine (n=694), and meth (n=474). Results suggest relatively low levels of use of non-primary heroin, cocaine, and meth, but moderate levels of alcohol and marijuana use. Growth models showed declining primary drug levels for heroin and meth users and relatively consistent levels over 10 years for cocaine users, while levels of non-primary drugs remained at consistently low levels or declined in tandem with the primary drug. Results indicate that group descriptions of primary heroin, cocaine, or meth use trajectories over time may present valid information about drug use patterns in general.

The effect of persistence of cocaine use on 12-month outcomes for the treatment of heroin dependence

AIMS

To determine the effects of cocaine use across the study period on outcomes of treatment for heroin dependence 12 months post-treatment entry.

DESIGN

Longitudinal cohort (12 months). Interviews were conducted at baseline, 3 and 12 months.

SETTING

Sydney, Australia.

PARTICIPANTS

Four hundred ninety-five heroin users recruited for the Australian Treatment Outcome Study and re-interviewed at 12-month follow-up.

FINDINGS

Cocaine was widely used among treatment entrants in NSW, with almost all having a lifetime history of cocaine use and almost half having used in the month preceding baseline. While there was an overall decline in cocaine use across the study period, individual use patterns varied widely. Approximately half of the cohort did not report cocaine use at any data point, with the remainder reporting having used at one (29%), two (12%), or at all three (5%) points. Cocaine use across the study period was an independent predictor of most major treatment outcomes, with more cocaine use points predicting poorer outcome. Persistent cocaine use predicted a higher prevalence of homelessness, heroin use, daily injecting, needle sharing and injection-related health problems at 12 months as well as more extensive recent polydrug use.

CONCLUSIONS

Cocaine use was common among individuals seeking treatment for primary heroin dependence in NSW. Any cocaine use over the study period was associated with poorer outcomes in virtually all areas. Persistent cocaine use over the study period, however, appeared particularly detrimental. Cocaine use among clients should evidently be a cause for concern amongst treatment providers and may warrant being specifically targeted during treatment.

Effects of 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) on the self-administration of cocaine, heroin, and cocaine/heroin combinations in rats

Pharmacotherapies utilizing long-acting agonists and mixed function agonists-antagonists have been successful in the treatment of opiate addiction but no comparable treatment exists for cocaine abuse. Long-acting tropane analogues have been synthesized that could be candidates for such pharmacotherapies. 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) is one such compound that is a relatively selective dopamine (DA) transporter blocker that has a significantly longer duration of action than cocaine. The purpose of this study was to assess the effects of PTT on the intravenous self-administration of cocaine, heroin, or cocaine/heroin combinations. Groups of rats were trained to self-administer cocaine, heroin, or cocaine/heroin combinations using a within session dosing procedure in which three doses were available each session. PTT pretreatment reduced cocaine and cocaine/heroin combinations intake in a dose-dependent manner while having only minor effects on heroin intake. These results suggest that the neurobiological substrates of cocaine and heroin self-administration are different, and that these cocaine/heroin combinations may function more like cocaine alone, even when the dose of heroin in the mixture will function independently as a reinforcer. These results further support the potential use of long-acting dopamine reuptake inhibitors as pharmacotherapeutic adjuncts to a comprehensive treatment program for cocaine and cocaine/heroin abuse.

Aktuelle Konsumformen bei Drogenabhängigkeit — Implikationen für Substitutionsprogramme in ambulanten Einrichtungen und bei behandelnden Ärzten

BACKGROUND

Anonymous evaluation of the current conditions of drug scene and drug consumption, entrance age, personal motives for drug consumption and satisfaction among opioid-dependent clients with treatments available within an ambulant maintenance treatment setting.

METHODS

The questionnaire for the study was based on representative studies and covered 112 questions regarding drug consumption. In addition, an instrument of the "Hessische Landesstelle gegen die Suchtgefahren", which measures satisfaction of opioid clients regarding public drug-treatment centers, was used.

RESULTS

A total of 158 opioid clients within an ambulant maintenance treatment setting were enrolled in the study. The mean age at first drug consumption was 15.1 (2.4) years for men and 15.2 (3.5) years for women. The Spearman correlation showed a significant positive correlation (r=0.284) between age and time of first drug consumption (p=0.019). Cannabis was the most frequent entrance drug (55.8%), followed by alcohol (33.8%), opioids (17.6%) and nicotine (11.8%). Additional consumption of benzodiazepines was observed in 44.7% of men and 39.7% of women, of cannabis in 74.5% of men and 52.4% of women, and of sustained-release morphine in 41.4% of men and 33.3% of women. Within the previous 6-12 months cocaine was consumed significantly less (p=0.024) by men (63.8%) than by women (90.5%). 93.3% of the drug users rated a follow-up assistance programme after withdrawal and 71.9% special care programmes for designer drugs very important.

IMPLICATIONS

The present study supports the assumption of an earlier age of first drug consumption. In view of our findings on entrance age, and on polytoxicomanic consumption patterns and gender-specific differences, we believe that the objectives of substitution programmes can only be reached if programmes are adequately adapted to the actual conditions of the drug scene and are able to cooperate with other public drug-treatment systems.