Early impact of methadone induction for heroin dependence: differential effects of two dose sequences in a randomized controlled study

Is craving a risk factor for substance use among treatment-seeking individuals with alcohol and other drugs use disorders? A meta-analytic review

BACKGROUND

It is still unclear whether craving should be considered a key risk factor for substance-use behaviors (SUB) among treatment-seeking individuals with alcohol (AUD) and other drugs use disorders. Therefore, this study aims at clarifying this topic using a meta-analytic approach.

METHODS

Cohen's d was computed as effect size (ES) measure. Heterogeneity of ESs was computed using the Q statistic and I² index. The analyses also evaluated the impact assessment length on ESs. Furthermore, proximal effects of craving on SUB were compared to distal ones. The diagnoses of specific substance use disorders (SUDs), together with assessment instruments and research design were considered as additional moderators.

RESULTS

Thirty-six independent studies were included for a total of 4868 treatment-seeking individuals with SUDs. Patients who used substances showed slightly higher levels of craving than abstinent ones. The heterogeneity of results was large and significant. The length of period of assessment was positively related to ESs. The analyses highlighted no differences between pooled ESs of proximal and distal impacts of craving on SUB. The diagnoses of SUDs were significant moderators. Considering AUD, assessment instruments and research design were additional moderators.

CONCLUSIONS

Craving is a modest time-dependent proximal and distal risk factor for SUB among individuals with SUDs. Both the frequency of craving episodes and a heightened reactivity to craving cues are largely associated to SUB among individuals with AUD. Future studies should evaluate the mediating and moderating roles of self-regulatory mechanisms on the relationship between craving and SUB.

Methadone maintenance dose modulates anterior cingulate glutamate levels in heroin-dependent individuals: A preliminary in vivo (1)H MRS study

Mu-opioid receptor agonists alter brain glutamate (GLU) levels in laboratory animals. This clinical study used proton magnetic resonance spectroscopy ((1)H MRS) to examine regional brain GLU levels during experimental manipulation of methadone (MTD) maintenance dose under double-blind, within-subject conditions in seven heroin-dependent volunteers. Subjects were scanned first at a high MTD dose (100 mg/day), underwent a 3-week outpatient MTD dose taper, and then were scanned again at a low MTD dose (10-25 mg/day; modified for participant comfort). Five age- and cigarette smoking-matched controls were scanned once. In vivo short echo time (TE = 22 ms), single voxel (1)H MRS data from midline pregenual anterior cingulate cortex (ACC) and thalamus (4.5 cm(3) each) were collected using PRESS on a 4-Tesla MRI system. Absolute metabolite levels were quantified. GLU levels in the ACC, but not the thalamus, were higher at the low relative to the high MTD dose in heroin-dependent subjects. No other metabolites differed by MTD dose, or between control vs. heroin-dependent subjects (at either MTD dose). GLU levels in the ACC were inversely related to the duration of cigarette smoking (controls) and heroin use (experimental group). Future studies are warranted to investigate the relationship between GLU levels during treatment (and detoxification), and withdrawal symptoms or relapse.

Methadone at tapered doses for the management of opioid withdrawal

BACKGROUND

The evidence of tapered methadone's efficacy in managing opioid withdrawal has been systematically evaluated in the previous version of this review that needs to be updated

OBJECTIVES

To evaluate the effectiveness of tapered methadone compared with other detoxification treatments and placebo in managing opioid withdrawal on completion of detoxification and relapse rate.

SEARCH METHODS

We searched: Cochrane Central Register of Controlled Trials (The Cochrane Library 2012, Issue 4), PubMed (January 1966 to May 2012), EMBASE (January 1988 to May 2012), CINAHL (2003- December 2007), PsycINFO (January 1985 to December 2004), reference lists of articles.

SELECTION CRITERIA

All randomised controlled trials that focused on the use of tapered methadone versus all other pharmacological detoxification treatments or placebo for the treatment of opiate withdrawal.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the included studies. Any doubts about how to rate the studies were resolved by discussion with a third review author. Study quality was assessed according to the criteria indicated in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Twenty-three trials involving 2467 people were included. Comparing methadone versus any other pharmacological treatment, we observed no clinical difference between the two treatments in terms of completion of treatment, 16 studies 1381 participants, risk ratio (RR) 1.08 (95% confidence interval (CI) 0.97 to 1.21); number of participants abstinent at follow-up, three studies, 386 participants RR 0.98 (95% CI 0.70 to 1.37); degree of discomfort for withdrawal symptoms and adverse events, although it was impossible to pool data for the last two outcomes. These results were confirmed also when we considered the single comparisons: methadone with: adrenergic agonists (11 studies), other opioid agonists (eight studies), anxiolytic (two studies), paiduyangsheng (one study). Comparing methadone with placebo (two studies) more severe withdrawal and more drop-outs were found in the placebo group. The results indicate that the medications used in the included studies are similar in terms of overall effectiveness, although symptoms experienced by participants differed according to the medication used and the program adopted.

AUTHORS' CONCLUSIONS

Data from literature are hardly comparable; programs vary widely with regard to the assessment of outcome measures, impairing the application of meta-analysis. The studies included in this review confirm that slow tapering with temporary substitution of long- acting opioids, can reduce withdrawal severity. Nevertheless, the majority of patients relapsed to heroin use.

Beyond drug use: a systematic consideration of other outcomes in evaluations of treatments for substance use disorders

Across the addictions field, the primary outcome in treatment research has been reduction in drug consumption. A comprehensive view of the impact of substance use disorders on human functioning suggests that effective treatments should address the many consequences and features of addiction beyond drug use, a recommendation forwarded by multiple expert panels and review papers. Despite recurring proposals, and a compelling general rationale for moving beyond drug use as the sole standard for evaluating addiction treatment, the field has yet to adopt any core set of 'other' measures that are routinely incorporated into treatment research. Among the many reasons for the limited impact of previous proposals has been the absence of a clear set of guidelines for selecting candidate outcomes. This paper is the result of the deliberations of a panel of substance abuse treatment and research experts convened by the National Institute on Drug Abuse to discuss appropriate outcome measures for clinical trials of substance abuse treatments. This paper provides an overview of previous recommendations and outlines specific guidelines for consideration of candidate outcomes. A list of outcomes meeting those guidelines is described and illustrated in detail with two outcomes: craving and quality of life. The paper concludes with specific recommendations for moving beyond the outcome listing offered in this paper to promote the programmatic incorporation of these outcomes into treatment research.

The clinical significance of drug craving

Although drug craving has received considerable research attention over the past several decades, to date there has been no systematic review of the general clinical significance of craving. This paper presents an overview of measurement issues of particular relevance to a consideration of use of craving in clinical settings. The paper then considers the relevance of craving across a broad array of clinical domains, including diagnosis, prognostic utility, craving as an outcome measure, and the potential value of craving as a direct target of intervention. The paper is both descriptive and prescriptive, informed by the current state of the science on craving with recommendations for the definition of craving, assessment practices, future research, and clinical applications. We conclude that craving has considerable utility for diagnosis and as a clinical outcome, and that findings from future research will likely expand the clinical potential of the craving construct in the domains of prognosis and craving as a treatment target.

Brain fMRI and craving response to heroin-related cues in patients on methadone maintenance treatment

OBJECTIVE

To investigate the subjective craving and brain response to heroin-related cues in former heroin addicts on long-term methadone maintenance treatment.

METHODS

Fourteen participants completed an event-related functional magnetic resonance imaging task including heroin-related and nonheroin-related (neutral) cues. Craving self-reports were collected before and after the task.

RESULTS

Although no significant craving changes were associated with the task, blood oxygen-level dependence intensity was significantly greater during exposure to heroin-related cues, compared to neutral cues in brain areas studied.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

The results indicate that the learned brain response of former heroin addicts to drug-related stimuli may persist despite long-term methadone maintenance treatment.

Behavioral economic analysis of drug preference using multiple choice procedure data

The multiple choice procedure has been used to evaluate preference for psychoactive drugs, relative to money amounts (price), in human subjects. The present re-analysis shows that MCP data are compatible with behavioral economic analysis of drug choices. Demand curves were constructed from studies with intravenous fentanyl, intramuscular hydromorphone and oral methadone in opioid-dependent individuals; oral d-amphetamine, oral MDMA alone and during fluoxetine treatment, and smoked marijuana alone or following naltrexone pretreatment in recreational drug users. For each participant and dose, the MCP crossover point was converted into unit price (UP) by dividing the money value ($) by the drug dose (mg/70kg). At the crossover value, the dose ceases to function as a reinforcer, so "0" was entered for this and higher UPs to reflect lack of drug choice. At lower UPs, the dose functions as a reinforcer and "1" was entered to reflect drug choice. Data for UP vs. average percent choice were plotted in log-log space to generate demand functions. Rank of order of opioid inelasticity (slope of non-linear regression) was: fentanyl>hydromorphone (continuing heroin users)>methadone>hydromorphone (heroin abstainers). Rank order of psychostimulant inelasticity was d-amphetamine>MDMA>MDMA+fluoxetine. Smoked marijuana was more inelastic with high-dose naltrexone. These findings show this method translates individuals' drug preferences into estimates of population demand, which has the potential to yield insights into pharmacotherapy efficacy, abuse liability assessment, and individual differences in susceptibility to drug abuse.

Contingency management: perspectives of Australian service providers

Given the very positive and extensive research evidence demonstrating efficacy and effectiveness of contingency management, it is important that Australia explore whether contingency management has a role to play in our own treatment context. Qualitative interviews were conducted with 30 experienced alcohol and drug practitioners, service managers and policy-makers in Victoria. Interviewees were selected to represent the range of drug treatment services types and included rural representation. A semi-structured interview schedule, covering their perceptions and practices of contingency management was used. All interviews were transcribed verbatim and analysed using N2 qualitative data analysis program. The majority of key informants were positively inclined toward contingency management, notwithstanding some concerns about the philosophical underpinnings. Concerns were raised in relation to the use of monetary rewards. Examples of the use of contingency management provided by key informants demonstrated an over-inclusive definition: all the examples did not adhere to the key principles of contingency management. This may create problems if a structured contingency management were to be introduced in Australia. Contingency management is an important adjunctive treatment intervention and its use in Australia has the potential to enhance treatment outcomes. No unmanageable barriers were identified in this study.

Buprenorphine duration of action: mu-opioid receptor availability and pharmacokinetic and behavioral indices

BACKGROUND

Buprenorphine (BUP) is effective in the treatment of opioid dependence when given on alternating days, probably as a result of long-lasting occupation of micro opioid receptors (microORs). This study examined the duration of action of BUP at microORs and correlations with pharmacokinetic and pharmacodynamic outcomes in 10 heroin-dependent volunteers.

METHODS

Availability of microOR (measured with positron emission tomography and [(11)C]-carfentanil), plasma BUP concentration, opioid withdrawal symptoms, and blockade of hydromorphone (HYD; heroin-like agonist) effects were measured at 4, 28, 52, and 76 hours after omitting the 16 mg/d dose of BUP in a study reported elsewhere.

RESULTS

Relative to heroin-dependent volunteers maintained on BUP placebo, whole-brain microOR availability was 30%, 54%, 67%, and 82% at 4, 28, 52, and 76 hours after BUP. Regions of interest showed similar effects. Plasma concentrations of BUP were time dependent, as were withdrawal symptoms, carbon dioxide sensitivity and extent of HYD blockade. Availability of microOR was also correlated with BUP plasma concentration, withdrawal symptoms, and HYD blockade.

CONCLUSIONS

Together with our previous findings, it appears that microOR availability predicts changes in pharmacokinetic and pharmacodynamic measures and that about 50%-60% BUP occupancy is required for adequate withdrawal symptom suppression (in the absence of other opioids) and HYD blockade.

Methadone tolerance testing in drug misusers

Asking drug misusers the dose they need for methadone maintenance might seem like an invitation to exaggerate, but experience in one practice suggests that it could improve uptake of treatment without compromising safety

Methadone at tapered doses for the management of opioid withdrawal

BACKGROUND

Despite widespread use in many countries the evidence of tapered methadone's efficacy in managing opioid withdrawal has not been systematically evaluated.

OBJECTIVES

To evaluate the effectiveness of tapered methadone compared with other detoxification treatments and placebo in managing opioid withdrawal on completion of detoxification and relapse rate.

SEARCH STRATEGY

We searched: Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005), MEDLINE (January 1966 to December 2004), EMBASE (January 1988 to December 2004), PsycINFO (January 1985 to December 2004), and reference lists of articles. We also contacted manufacturers and researchers in the field.

SELECTION CRITERIA

All randomised controlled trials which focus on the use of tapered methadone versus all other pharmacological detoxification treatments or placebo for the treatment of opiate withdrawal.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the included studies. Any doubt about how to rate the studies were resolved by discussion with a third reviewer. Study quality was assessed according to the criteria indicated in Cochrane Reviews Handbook 4.2. (Alderson 2004)

MAIN RESULTS

Sixteen trials involving 1187 people were included. Comparing methadone versus any other pharmacological treatment we observed no clinical difference between the two treatments in terms of completion of treatment, relative risk (RR) 1.12; 95% CI 0.94 to 1.34 and results at follow-up RR 1.17; 95% CI 0.72 to 1.92. It was impossible to pool data for the other outcomes but the results of the studies did not show significant differences between the considered treatments. These results were confirmed also when we considered the single comparisons: methadone with: adrenergic agonists (11 studies), other opioid agonists (four studies), chlordiazepoxide (study). Comparing methadone with placebo (one study) more severe withdrawal and more drop outs were found in the placebo group. The results indicate that the medications used in the included studies are similar in terms of overall effectiveness, although symptoms experienced by participants differed according to the medication used and the program adopted.

AUTHORS' CONCLUSIONS

Data from literature are hardly comparable; programs vary widely with regard to duration, design and treatment objectives, impairing the application of meta-analysis. The studies included in this review confirm that slow tapering with temporary substitution of long acting opioids, accompanied by medical supervision and ancillary medications can reduce withdrawal severity. Nevertheless the majority of patients relapsed to heroin use.