Randomized controlled trial of dexamphetamine maintenance for the treatment of methamphetamine dependence

Co-targeting the kappa opioid receptor and dopamine transporter reduces motivation to self-administer cocaine and partially reverses dopamine system dysregulation

Cocaine disrupts dopamine (DA) and kappa opioid receptor (KOR) system activity, with long-term exposure reducing inhibiton of DA uptake by cocaine and increasing KOR system function. Single treatment therapies have not been successful for cocaine use disorder; therefore, this study focuses on a combination therapy targeting the dopamine transporter (DAT) and KOR. Sprague Dawley rats self-administered 5 days of cocaine (1.5 mg/kg/inf, max 40 inf/day, FR1), followed by 14 days on a progressive ratio (PR) schedule (0.19 mg/kg/infusion). Behavioral effects of individual and combined administration of phenmetrazine and nBNI were then examined using PR. Additionally, ex vivo fast scan cyclic voltammetry was then used to assess alterations in DA and KOR system activity in the nucleus accumbens before and after treatments. Chronic administration of phenmetrazine as well as the combination of phenmetrazine and nBNI-but not nBNI alone-significantly reduced PR breakpoints. In addition, the combination of phenmetrazine and nBNI partially reversed cocaine-induced neurodysregulations of the KOR and DA systems, indicating therapeutic benefits of targeting the DA and KOR systems in tandem. These data highlight the potential benefits of the DAT and KOR as dual-cellular targets to reduce motivation to administer cocaine and reverse cocaine-induced alterations of the DA system.

Perceptions of prospective pharmaceutical stimulant substitution treatments among people who use illicit stimulants in Vancouver, Canada

BACKGROUND

Stimulant-involved overdose deaths are increasing, driven by polysubstance use and adulteration of the illicit drug supply. While emerging evidence for prescription stimulant substitution is promising, there are no approved treatment options for stimulant use disorder that address the realities of an unpredictable drug supply. This study explores treatment experiences of people who use illicit stimulants (PWUS) to identify gaps and perceptions of prospective pharmaceutical stimulant substitution treatments (SST).

METHODS

In-depth qualitative interviews were conducted with 86 PWUS in Vancouver, Canada. Thematic analysis focused on experiences of available treatment options for stimulant use and perceptions of prospective SST.

RESULTS

Participants identified how primarily behavioral treatment approaches do not meet the unique needs of PWUS, in contrast with the range of medical treatments available for opioid use disorder. Participants anticipated health and social benefits if they were able to access SST, including avoiding the toxic illicit stimulant supply, reduced engagement in criminalized activities, and greater economic security. Perceptions of prospective SST were informed by knowledge of existing opioid treatments. This led some participants to be unsupportive of SST, citing concerns around agency and highly regulated operational contexts that do not align with the lived realities of stimulant use.

CONCLUSION

Findings demonstrate the need for SST pilot programs in real-world settings and underscore the health and social advantages SST may offer; although drawing on existing opioid treatment models to implement SST pilots may limit success. Thus, any novel treatments for stimulant use must centre the lived realities of PWUS.

Prescription psychostimulants for the treatment of amphetamine-type stimulant use disorder: A systematic review and meta-analysis of randomized placebo-controlled trials

BACKGROUND AND AIMS

There is currently no standard of care for pharmacological treatment of amphetamine-type stimulant (ATS) use disorder (ATSUD). This systematic review with meta-analysis (PROSPERO CRD42022354492) aimed to pool results from randomized placebo-controlled trials (RCTs) to evaluate efficacy and safety of prescription psychostimulants (PPs) for ATSUD.

METHODS

Major indexing sources and trial registries were searched to include records published before 29 August 2022. Eligible studies were RCTs evaluating efficacy and safety of PPs for ATSUD. Risk of bias (RoB) was assessed using the Cochrane RoB 2 tool. Risk ratio (RR) and risk difference were calculated for random-effect meta-analysis of dichotomous variables. Mean difference and standardized mean difference (SMD) were calculated for random-effect meta-analysis of continuous variables.

RESULTS

Ten RCTs (n = 561 participants) were included in the meta-analysis. Trials studied methylphenidate (n = 7), with daily doses of 54-180 mg, and dextroamphetamine (n = 3), with daily doses of 60-110 mg, for 2-24 weeks. PPs significantly decreased end-point craving [SMD  -0.29; 95% confidence interval (CI) = -0.55, -0.03], while such a decrease did not reach statistical significance for ATS use, as evaluated by urine analysis (UA) (RR = 0.93; 95% CI = 0.85-1.01). No effect was observed for self-reported ATS use, retention in treatment, dropout following adverse events, early-stage craving, withdrawal and depressive symptoms. In a sensitivity analysis, treatment was associated with a significant reduction in UA positive for ATS (RR = 0.89; 95% CI = 0.79-0.99) after removing studies with a high risk of bias. In subgroup analyses, methylphenidate and high doses of PPs were negatively associated with ATS use by UA, while higher doses of PPs and treatment duration (≥ 20 weeks) were positively associated with longer retention.

CONCLUSIONS

Among individuals with amphetamine-type stimulant use disorder, treatment with prescription psychostimulants may decrease ATS use and craving. While effect size is limited, it may increase with a higher dosage of medications.

Psychosocial and pharmacologic interventions for problematic methamphetamine use: Findings from a scoping review of the literature

RATIONALE

Methamphetamine use and related harms have risen at alarming rates. While several psychosocial and pharmacologic interventions have been described in the literature, there is uncertainty regarding the best approach for the management of methamphetamine use disorder (MUD) and problematic methamphetamine use (PMU). We conducted a scoping review of recent systematic reviews (SR), clinical practice guidelines (CPG), and primary controlled studies of psychosocial and pharmacologic treatments for MUD/PMU.

METHODS

Guided by an a priori protocol, electronic database search updates (e.g., MEDLINE, Embase) were performed in February 2022. Screening was performed following a two-stage process, leveraging artificial intelligence to increase efficiency of title and abstract screening. Studies involving individuals who use methamphetamine, including key subgroups (e.g. those with mental health comorbidities; adolescents/youths; gay, bisexual, and other men who have sex with men) were sought. We examined evidence related to methamphetamine use, relapse, use of other substances, risk behaviors, mental health, harms, and retention. Figures, tables and descriptive synthesis were used to present findings from the identified literature.

RESULTS

We identified 2 SRs, one CPG, and 54 primary studies reported in 69 publications that met our eligibility criteria. Amongst SRs, one concluded that psychostimulants had no effect on methamphetamine abstinence or treatment retention while the other reported no effect of topiramate on cravings. The CPG strongly recommended psychosocial interventions as well as self-help and family support groups for post-acute management of methamphetamine-related disorders. Amongst primary studies, many interventions were assessed by only single studies; contingency management was the therapy most commonly associated with evidence of potential effectiveness, while bupropion and modafinil were analogously the most common pharmacologic interventions. Nearly all interventions showed signs of potential benefit on at least one methamphetamine-related outcome measure.

DISCUSSION

This scoping review provides an overview of available interventions for the treatment of MUD/PMU. As most interventions were reported by a single study, the effectiveness of available interventions remains uncertain. Primary studies with longer durations of treatment and follow-up, larger sample sizes, and of special populations are required for conclusive recommendations of best approaches for the treatment of MUD/PMU.

Identifying early intervention opportunities for illicit stimulant use: A cross-sectional study of factors associated with illicit stimulant use among young people accessing integrated youth services in British Columbia, Canada

INTRODUCTION

Illicit stimulant (cocaine and/or amphetamine) use among young people aged 12-24 is a public health priority given that substance use initiation tends to peak in this developmental period and significant associated immediate and long-term harms are associated with its use. Young people using stimulants must be engaged in services as early as possible to reduce these harms. To inform early intervention opportunities, this study aimed to identify the risk/protective factors associated with illicit stimulant use among young people.

METHODS

We conducted a cross-sectional study on routinely collected self-reported data among young people accessing integrated youth services in British Columbia (Canada) between April 2018 and January 2022. Data were collected on young peoples' socio-demographic characteristics, and social, behavioral, and health profiles. Variable selection was guided by established risk/protective factors for substance use among young people. The study used multivariable logistic regression to identify risk/protective factors that were independently associated with past 30-day illicit stimulant use.

RESULTS

The analytic sample included n = 5620 young people aged 12-24 and a total of 163 (2.9 %) reported past 30-day illicit cocaine and/or amphetamine use. Demographic characteristics that were independently associated with illicit stimulant use included older age (aOR = 1.27, 95 % CI = 1.17-1.38) and gender identity as man vs woman (aOR = 1.71, 95 % CI = 1.10-2.70). Social and environmental risk factors included recently witnessing or experiencing violence (aOR = 2.32, 95 % CI = 1.47-3.68) and higher past-year crime/violent behaviors score (aOR = 1.39, 95 % CI = 1.13-1.69). Finally, regular alcohol (aOR = 6.90, 95 % CI = 2.36-25.42), regular (aOR = 3.74, 95 % CI = 1.95-7.54) or social (aOR = 3.06, 95 % CI = 1.44-6.60) tobacco use, and lifetime hallucinogen (aOR = 3.24, 95 % CI = 1.8-5.91) and ecstasy/MDMA (aOR = 2.53, 95 % CI = 1.48-4.39) use were also statistically significant risk factors.

CONCLUSIONS

These risk/protective factors support identification of young people who may benefit from further screening, assessment, and treatment for illicit stimulant use. This study also underscores the need to expand early intervention and harm reduction programs that can comprehensively respond to young peoples' stimulant use, health, and social needs.

Identification of Potential Biomarkers for Diagnosis of Patients with Methamphetamine Use Disorder

The current method for diagnosing methamphetamine use disorder (MUD) relies on self-reports and interviews with psychiatrists, which lack scientific rigor. This highlights the need for novel biomarkers to accurately diagnose MUD. In this study, we identified transcriptome biomarkers using hair follicles and proposed a diagnostic model for monitoring the MUD treatment process. We performed RNA sequencing analysis on hair follicle cells from healthy controls and former and current MUD patients who had been detained in the past for illegal use of methamphetamine (MA). We selected candidate genes for monitoring MUD patients by performing multivariate analysis methods, such as PCA and PLS-DA, and PPI network analysis. We developed a two-stage diagnostic model using multivariate ROC analysis based on the PLS-DA method. We constructed a two-step prediction model for MUD diagnosis using multivariate ROC analysis, including 10 biomarkers. The first step model, which distinguishes non-recovered patients from others, showed very high accuracy (prediction accuracy, 98.7%). The second step model, which distinguishes almost-recovered patients from healthy controls, showed high accuracy (prediction accuracy, 81.3%). This study is the first report to use hair follicles of MUD patients and to develop a MUD prediction model based on transcriptomic biomarkers, which offers a potential solution to improve the accuracy of MUD diagnosis and may lead to the development of better pharmacological treatments for the disorder in the future.

The efficacy of an internet-based cognitive behavioral program added to treatment-as-usual for alcohol-dependent patients in primary care: a randomized controlled trial

BACKGROUND AND AIMS

Most alcohol-dependent people have a moderate level of dependence. General practitioners (GPs) hesitate to engage in this area, and need to have access to treatment they find applicable and feasible to use. The aim of this present study was to test if an open-ended internet-based cognitive-behavioral therapy (iCBT) program added to treatment-as-usual (TAU) is more effective than TAU-only for alcohol-dependent patients in primary care.

DESIGN, SETTING AND PARTICIPANTS

The present study was a two-group, parallel, randomized controlled superiority trial comparing iCBT+TAU versus TAU-only at 3- and 12-month follow-ups. TAU was delivered at 14 primary care centers in Stockholm, Sweden. A total of 264 patients (mean age 51 years, of whom 148 were female and 116 were male) with alcohol dependence and hazardous alcohol consumption were enrolled between September 2017 and November 2019.

MEASUREMENTS

Participants were randomized at a ratio of 1:1 to iCBT, as a self-help intervention added to TAU (n = 132) or to TAU-only (n = 132). The GPs gave participants in both treatment arms feedback on the assessments and biomarkers and offered TAU at the primary care center. Primary outcome was weekly alcohol consumption in g/week at 12-month follow-up, analyzed according to intention-to-treat (n = 132 + 132). The per-protocol analysis included participants who completed at least one module of iCBT (n = 102 + 132).

FINDINGS

There was no significant difference in weekly alcohol consumption between iCBT+TAU and TAU in the intention-to-treat (ITT) analysis at 12-month follow-up [iCBT+TAU = 133.56 (95% confidence interval, CI = 100.94-166.19) and TAU = 176.20 (95% CI = 144.04-208.35), P = 0.068, d = 0.23]. In the per-protocol analysis, including only those who initiated iCBT, the iCBT+TAU group showed lower mean weekly alcohol consumption compared with TAU [iCBT+TAU = 107.46 (95% CI = 71.17-143.74), TAU = 176.00 (95% CI = 144.21-207.80), P = 0.010, d = 0.42].

CONCLUSIONS

In Sweden, an internet-based cognitive-behavioral program added to treatment-as-usual to reduce alcohol consumption showed weak evidence of a benefit at 12 months in the intention-to-treat analysis and good evidence of a benefit in the per-protocol analysis.

A Human Oral Fluid Assay for D- and L- Isomer Detection of Amphetamine and Methamphetamine Using Liquid-Liquid Extraction

Medical providers are increasingly confronted with clinical decision-making that involves (meth)amphetamines. And clinical laboratories need a sensitive, efficient assay for routine assessment of D- and L-isomers to determine the probable source of these potentially illicit analytes. This paper presents a validated method of D- and L-isomer detection in human oral fluid from an extract used for determination of a large oral fluid assay (63 analytes) on an older AB SCIEX 4000 instrument. Taken from the positive extract, D- and L-analytes were added. The method for extraction included addition of internal standard and a 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples. The samples were suspended in 50% MeOH in water, diluted with mobile phase, with separation and detection accomplished using LC-MS/MS to determine analyte concentration. Once samples were confirmed positive for (meth)amphetamine from the large oral fluid assay, they were further examined for the enantiomeric forms with 50 μl aliquots of the standards and samples of interest combined with 450 μl of D- and L-assay mobile phase, then analyzed using chiral column separation, and LC-MS/MS detection with standard curve spanning the range from 2.5 to 1000 ng/mL. The result is a sensitive and accurate detection of D- and L-isomers of amphetamine and methamphetamine in human oral fluid performed on an older model mass spectrometer (AB SCIEX 4000). The novelty of this assay is twofold (a) the 2-step liquid-liquid extraction and dry-down step to concentrate and clean the samples, and (b) its adoption characteristics as a reflex test from a large ODT panel without the need to invest in newer or expensive LC-MS/MS instruments. Finally, this assay also has potential to add a valuable option to high-throughput laboratories seeking a D- and L-testing alternative to urine drug testing methods.

Multiple comparison of different noninvasive brain stimulation and pharmacologic interventions in patients with methamphetamine use disorders: A network meta-analysis of randomized controlled trials

AIM

In recent decades, the prevalence of amphetamine and methamphetamine use disorders has at least doubled in some regions/countries, with accompanying high risks of drug overdose-associated mortality. Noninvasive brain stimulation (NIBS) methods may be effective treatments. However, the comparative efficacy of the NIBS protocol for amphetamine/methamphetamine use disorder (AUD/MUD) remains unknown to date. The aim of this network meta-analysis (NMA) was to compare the efficacy and acceptability of various NIBS methods/protocols for AUD/MUD management.

METHODS

A frequentist model-based NMA was conducted. We included randomized controlled trials (RCTs) that investigated the efficacy of NIBS and guideline-recommended pharmacologic treatments to reduce craving severity in patients with either AUD or MUD.

RESULTS

Twenty-two RCTs including 1888 participants met the eligibility criteria. Compared with the sham/placebo group (study = 19, subjects = 891), a combination of intermittent theta burst stimulation over the left dorsolateral prefrontal cortex (DLPFC) and continuous TBS over the left ventromedial prefrontal cortex (study = 1, subjects = 19) was associated with the largest decreases in craving severity [standardized mean difference (SMD) = -1.50; 95% confidence intervals (95%CIs) = -2.70 to -0.31]. High-frequency repetitive transcranial magnetic stimulation over the left DLPFC was associated with the largest improvements in depression and quality of sleep (study = 3, subjects = 86) (SMD = -2.48; 95%CIs = -3.25 to -1.71 and SMD = -2.43; 95%CIs = -3.38 to -1.48, respectively). The drop-out rate of most investigated treatments did not significantly differ between groups.

CONCLUSION

The combined TBS protocol over the prefrontal cortex was associated with the greatest improvement in craving severity. Since few studies were available for inclusion, additional large-scale randomized controlled trials are warranted.

Lisdexamfetamine for the treatment of acute methamphetamine withdrawal: A pilot feasibility and safety trial

BACKGROUND

There is no effective treatment for methamphetamine withdrawal. This study aimed to determine the feasibility and safety of a tapering dose of lisdexamfetamine for the treatment of acute methamphetamine (MA) withdrawal.

METHODS

Open-label, single-arm pilot study, in an inpatient drug and alcohol withdrawal unit assessing a tapering dose of oral lisdexamfetamine dimesylate commencing at 250 mg once daily, reducing by 50 mg per day to 50 mg on Day 5. Measures were assessed daily (days 0-7) with 21-day telephone follow-up. Feasibility was measured by the time taken to enrol the sample. Safety was the number of adverse events (AEs) by system organ class. Retention was the proportion to complete treatment. Other measures included the Treatment Satisfaction Questionnaire for Medication (TSQM), the Amphetamine Withdrawal Questionnaire and craving (Visual Analogue Scale).

RESULTS

Ten adults seeking inpatient treatment for MA withdrawal (9 male, median age 37.1 years [IQR 31.7-41.9]), diagnosed with MA use disorder were recruited. The trial was open for 126 days; enroling one participant every 12.6 days. Eight of ten participants completed treatment (Day 5). Two participants left treatment early. There were no treatment-related serious adverse events (SAEs). Forty-seven AEs were recorded, 17 (36%) of which were potentially causally related, all graded as mild severity. Acceptability of the study drug by TSQM was rated at 100% at treatment completion. Withdrawal severity and craving reduced through the admission.

CONCLUSION

A tapering dose regimen of lisdexamfetamine was safe and feasible for the treatment of acute methamphetamine withdrawal in an inpatient setting.

Trial protocol of an open label pilot study of lisdexamfetamine for the treatment of acute methamphetamine withdrawal

Introduction

Methamphetamine (MA) use disorder is an important public health concern. MA withdrawal is often the first step in ceasing or reducing use. There are no evidence-based withdrawal treatments, and no medication is approved for the treatment of MA withdrawal. Lisdexamfetamine (LDX) dimesilate, used in the treatment of attention deficit hyperactivity disorder and binge eating disorder has the potential as an agonist therapy to ameliorate withdrawal symptoms, and improve outcomes for patients.

Methods

A single arm, open-label pilot study to test the safety and feasibility of LDX for the treatment of MA withdrawal. Participants will be inpatients in a drug and alcohol withdrawal unit, and will receive a tapering dose of LDX over five days: 250mg LDX on Day 1, reducing by 50mg per day to 50mg on Day 5. Optional inpatient Days 6 and 7 will allow for participants to transition to ongoing treatment. Participants will be followed-up on Days 14, 21 and 28. All participants will also receive standard inpatient withdrawal care. The primary outcomes are safety (measured by adverse events, changes in vital signs, changes in suicidality and psychosis) and feasibility (the time taken to enrol the sample, proportion of screen / pre-screen failures). Secondary outcomes are acceptability (treatment satisfaction questionnaire, medication adherence, concomitant medications, qualitative interviews), retention to protocol (proportion retained to primary and secondary endpoints), changes in withdrawal symptoms (Amphetamine Withdrawal Questionnaire) and craving for MA (visual analogue scale), and sleep outcomes (continuous actigraphy and daily sleep diary).

Discussion

This is the first study to assess lisdexamfetamine for the treatment of acute MA withdrawal. If safe and feasible results will go to informing the development of multi-centre randomised controlled trials to determine the efficacy of the intervention.

A mechanistic overview of approaches for the treatment of psychostimulant dependence

Psychostimulant use disorder is a major health issue around the world with enormous individual, family-related and societal consequences, yet there are no effective pharmacological treatments available. In this review, a target-based overview of pharmacological treatments toward psychostimulant addiction will be presented. We will go through therapeutic approaches targeting different aspects of psychostimulant addiction with focus on three major areas; 1) drugs targeting signalling, and metabolism of the dopamine system, 2) drugs targeting either AMPA receptors or metabotropic glutamate receptors of the glutamate system and 3) drugs targeting the severe side-effects of quitting long-term psychostimulant use. For each of these major modes of intervention, findings from pre-clinical studies in rodents to clinical trials in humans will be listed, and future perspectives of the different treatment strategies as well as their potential side-effects will be discussed. Pharmaceuticals modulating the dopamine system, such as antipsychotics, DAT-inhibitors, and disulfiram, have shown some promising results. Cognitive enhancers have been found to increase aspects of behavioural control, and drugs targeting the glutamate system such as modulators of metabotropic glutamate receptors and AMPA receptors have provided interesting changes in relapse behaviour. Furthermore, CRF-antagonists directed toward alleviating the symptoms of the withdrawal stage have been examined with interesting resulting changes in behaviour. There are promising results investigating therapeutics for psychostimulant addiction, but further preclinical work and additional human studies with a more stratified patient selection are needed to prove sufficient evidence of efficacy and tolerability.

Ifenprodil for the treatment of methamphetamine use disorder: An exploratory, randomized, double‐blind, placebo‐controlled trial

Aim

No effective pharmacological interventions have been developed for patients with methamphetamine use disorder. Ifenprodil is a blocker of G protein‐activated inwardly rectifying potassium channels, which play a key role in the mechanism of action of addictive substances. We conducted a randomized, double‑blind, exploratory, dose‐ranging, placebo‐controlled trial to examine the clinical efficacy of ifenprodil for the treatment of methamphetamine use disorder.

Methods

Participants were assigned to three groups: placebo, 60 mg/d ifenprodil, or 120 mg/d ifenprodil. The drug administration period was 84 days. The primary outcome was the use or nonuse of methamphetamine during the drug administration period in the placebo group vs 120 mg/d ifenprodil group. We also assessed drug use status, relapse risk based on the Stimulant Relapse Risk Scale (SRRS), drug craving, and methamphetamine in urine as secondary outcomes. We further evaluated drug use status and SRRS subscale scores in patients who were not taking addiction medications during the study.

Results

Ifenprodil did not affect the primary or secondary outcomes. However, the additional analyses showed that the number of days of methamphetamine use during the follow‐up period and scores on the emotionality problems subscale of the SRRS improved in the 120 mg/d ifenprodil group. The safety of ifenprodil was confirmed in patients with methamphetamine use disorder.

Conclusion

The present findings did not confirm the efficacy of ifenprodil for methamphetamine use disorder treatment based on the primary or secondary outcomes, but we found evidence of its safety and efficacy in reducing emotionality problems.

Clinical trial registration

The study was registered at the University Hospital Medical Information Network Clinical Trial Registry (no. UMIN000030849) and Japan Registry of Clinical Trials (no. jRCTs031180080). The main registration site is jRCT (https://jrct.niph.go.jp/).

We conducted an exploratory, randomized, double‐blind, placebo‐controlled trial to investigate the clinical safety and efficacy of ifenprodil for the treatment of methamphetamine use disorder in Japanese patients. Our findings confirmed the safety of ifenprodil, and ifenprodil at the highest dose exerted slight efficacy.

Are Histamine H3 Antagonists the Definitive Treatment for Acute Methamphetamine Intoxication?

BACKGROUND

Methamphetamine (METH) is classified as a Schedule II stimulant drug under the United Nations Convention on Psychotropic Substances of 1971. METH and other amphetamine analogues (AMPHs) are powerful addictive drugs. Treatments are needed to treat the symptoms of METH addiction, chronic METH use, and acute METH overdose. No effective treatment for METH abuse has been established because alterations of brain functions under the excessive intake of abused drug intake are largely irreversible due in part to brain damage that occurs in the course of chronic METH use.

OBJECTIVE

Modulation of brain histamine neurotransmission is involved in several neuropsychiatric disorders, including substance use disorders. This review discusses the possible mechanisms underlying the therapeutic effects of histamine H₃ receptor antagonists on symptoms of methamphetamine abuse.

CONCLUSION

Treatment of mice with centrally acting histamine H₃ receptor antagonists increases hypothalamic histamine contents and reduces high-dose METH effects while potentiating lowdose effects via histamine H₃ receptors that bind released histamine. On the basis of experimental evidence, it is hypothesized that histamine H₃ receptors may be an effective target for the treatment METH use disorder or other adverse effects of chronic METH use.

Utility of a controlled amphetamine withdrawal paradigm among adults who use methamphetamine: A pilot clinical trial

BACKGROUND

The continued increase in prevalence of methamphetamine use in the United States has resulted in a significant increase in the number of patients entering treatment for methamphetamine use. However, no robustly efficacious pharmacologic treatment for methamphetamine use or withdrawal has been identified to date after stopping methamphetamine use.

AIMS

Given the association between methamphetamine withdrawal and relapse during early treatment, this study tested a controlled d-amphetamine withdrawal paradigm among methamphetamine-using individuals.

METHODS

Treatment-seeking adults who used methamphetamine (N = 34; 47% female; 100% white) were enrolled in a 4-week, randomized, double-blind, placebo-controlled trial in a residential setting, in which all participants were maintained on d-amphetamine (30 mg BID) during week 1, then half were switched to placebo during weeks 2-3. All participants received placebo during week 4. Outcomes included vital signs, withdrawal, cravings for methamphetamine, mood, and cognition. Bivariate analyses tested treatment group differences on baseline demographic and outcome variables. Repeated measures models examined main and interaction effects of treatment over time.

RESULTS/OUTCOMES

Participants were successfully randomized and safely stabilized on d-amphetamine. Craving for methamphetamine increased during weeks 2-3 in the placebo group relative to those on d-amphetamine. Interactions with age and heart rate were noted.

CONCLUSIONS/INTERPRETATION

To our knowledge, this is the first double-blind, placebo-controlled trial measuring pharmacologic effects of abruptly stopping controlled d-amphetamine administration in adults who use methamphetamine. Results support the potential of this withdrawal paradigm to further examine the efficacy of pharmacologic agents in ameliorating methamphetamine withdrawal symptoms.

Exploring the effectiveness of dextroamphetamine for the treatment of stimulant use disorder: a qualitative study with patients receiving injectable opioid agonist treatment

Background

A high proportion of people receiving both oral and injectable opioid agonist treatment report concurrent use of stimulants (i.e. cocaine and or amphetamines), which has been associated with higher rates of continued illicit opioid use and treatment dropout. A recent randomized controlled trial demonstrated the effectiveness of dextroamphetamine (a prescribed stimulant) at reducing craving for and use of cocaine among patients receiving injectable opioid agonist treatment. Following this evidence, dextroamphetamine has been prescribed to patients with stimulant use disorder at a clinic in Vancouver. This study investigates perceptions of the effectiveness of dextroamphetamine from the perspective of these patients.

Methods

Data were collected using small focus groups and one-on-one interviews with patients who were currently or formerly receiving dextroamphetamine (n = 20). Thematic analysis was conducted using an iterative approach, moving between data collection and analysis to search for patterns in the data across transcripts. This process led to the defining and naming of three central themes responding to the research question.

Results

Participants reported a range of stimulant use types, including cocaine (n = 8), methamphetamine (n = 8), or both (n = 4). Three central themes were identified as relating to participants’ perceptions of the effectiveness of the medication: 1) achieving a substitution effect (i.e. extent to which dextroamphetamine provided a substitution for the effect they received from use of illicit stimulants); 2) Reaching a preferred dose (i.e. speed of titration and effect of the dose received); and 3) Ease of medication access (i.e. preference for take home doses (i.e. carries) vs. medication integrated into care at the clinic).

Conclusion

In the context of continued investigation of pharmacological treatments for stimulant use disorder, the present study has highlighted how the study of clinical outcomes could be extended to account for factors that contribute to perceptions of effectiveness from the perspective of patients. In practice, elements of treatment delivery (e.g. dosing and dispensation protocols) can be adjusted to allow for various scenarios (e.g. on site vs. take home dosing) by which dextroamphetamine and other pharmacological stimulants could be implemented to provide “effective” treatment for people with a wide range of treatment goals and needs.

Factors associated with methamphetamine use in Japanese people who died of unnatural causes: Analysis using forensic autopsy reports

This study aimed to examine factors related to methamphetamine use in Japanese people who died of unnatural causes. This study used a cross-sectional design. A total of 3343 forensic autopsy reports were obtained from two forensic medicine departments in the Kanto region of Japan. We classified the decedents who underwent forensic autopsies into methamphetamine/amphetamine (MA) and undetected (comparison) groups based on toxicological examination. We matched the decedents in the MA group with those in the comparison group at a 1:4 ratio based on sex and age. The variables, including gang members, criminal records, tattoos, body mass index, infections, concurrent psychotropic drug use, and cause of death, were compared between the groups. Of the 3343 decedents, we matched 109 in the MA group with 436 in the comparison group. Methamphetamine use was significantly associated with gang membership (13.8% vs. 3%, p < 0.001), criminal records unrelated to methamphetamine (47.7% vs. 13.8%, p < 0.001), tattoos (29.2% vs. 6.4%, p < 0.001), and hepatitis C virus infection (48.0% vs. 3.6%, p < 0.001). One-third of the patients in the MA group died from poisoning. This is the first study to show the physical and social characteristics associated with methamphetamine use in Japanese people who died of unnatural causes. Our results could be extended to people with methamphetamine use disorder at risk of death and enable the development of policies and practices to provide necessary intervention in a timely manner.

Evaluation of risk mitigation measures for people with substance use disorders to address the dual public health crises of COVID-19 and overdose in British Columbia: a mixed-method study protocol

INTRODUCTION

The COVID-19 pandemic was preceded by an ongoing overdose crisis and linked to escalating drug overdose deaths in British Columbia (BC). At the outset of these dual public health emergencies, the BC government announced interim Risk Mitigation Guidance (RMG) that permitted prescribing medication alternatives to substances, including opioids, alcohol, stimulants and benzodiazepines, an intervention sometimes referred to as 'safe supply'. This protocol outlines the approach for a study of the implementation of RMG and its impacts on COVID-19 infection, drug-related and systemic harms, continuity of care for people with substance use disorder (SUD), as well as their behavioural, psychosocial and well-being outcomes.

METHODS AND ANALYSIS

We conducted a parallel mixed-method study that involved both analysis of population-level administrative health data and primary data collection, including a 10-week longitudinal observational study (target n=200), a cross-sectional survey (target n=200) and qualitative interviews (target n=60). We implemented a participatory approach to this evaluation, partnering with people with lived or living expertise of drug use, and researchers and public health decision-makers across the province. Linked population-level administrative databases will analyse data from a cohort of BC residents with an indication of SUD between 1996 and 2020. We will execute high-dimensional propensity score matching and marginal structural modelling to construct a control group and to assess the impact of RMG dispensation receipt on a collaboratively determined set of primary and secondary outcomes.

ETHICS AND DISSEMINATION

Study activities were developed to adhere to the Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans, recommended COVID-19 research practices, and guided by the Truth and Reconciliation Commission's Calls to Action for public health, data governance and research ethics related to Indigenous people. Results will be disseminated incrementally, on an ongoing basis, through the consortium established for this study, then published in peer-reviewed journals.

Use of sustained release dextroamphetamine for the treatment of stimulant use disorder in the setting of injectable opioid agonist treatment in Canada: a case report

BACKGROUND

For people with opioid use disorder who are not responding to oral opioid agonist treatment, evidence supports the effectiveness of injectable opioid agonist treatment with injectable hydromorphone (an opioid analgesic) and diacetylmorphine (pharmaceutical grade heroin). While this treatment is effective at reducing illicit opioid use, concurrent cocaine use is prevalent. Dextroamphetamine (a central nervous system stimulant) has been found to be a safe and effective treatment for cocaine dependence among people receiving injectable opioid agonist treatment in Europe. We present the first report of dextroamphetamine prescribing offered for the treatment of stimulant use disorder among a patient receiving iOAT outside of a clinical trial. This case report can be used to inform clinical practice in the treatment of cocaine use disorder, an area where interventions are currently lacking.

CASE PRESENTATION

Dextroamphetamine was prescribed to a 51-year-old male who was diagnosed with concurrent opioid and stimulant use disorder in an injectable opioid agonist treatment clinic in Vancouver, Canada. He reported smoking crack cocaine daily for more than two decades and was experiencing health consequences associated with this use. He presented to his routine physician visit with the goal of reducing his cocaine use and was prescribed dextroamphetamine for the treatment of stimulant use disorder. After 4-weeks the patient was tolerating the medication with no observed adverse events and was achieving his therapeutic goal of reducing his cocaine use.

CONCLUSIONS

Dextroamphetamine can be prescribed to support patients with stimulant use disorder to reduce or stop their use of cocaine. The case demonstrated that when dextroamphetamine was prescribed, a significant reduction in cocaine use was experienced among a patient that had been regularly using cocaine on a daily basis for many years. Daily contact with care for the opioid medication promoted adherence to the stimulant medication and allowed for monitoring of dose and tolerance. Settings where patients are in regular contact with care such as oral and injectable opioid agonist treatment clinics serve as a suitable location to integrate dextroamphetamine prescribing for patients that use illicit stimulants to reduce use and associated harms.

Safety and tolerability of oral lisdexamfetamine in adults with methamphetamine dependence: a phase-2 dose-escalation study

OBJECTIVES

To examine the safety of an agonist-type treatment, lisdexamfetamine (LDX), at 250 mg/day among adults with methamphetamine (MA) dependence.

DESIGN

A dose-escalating, phase-2, open-label, single-group study of oral LDX at two Australian drug treatment services.

SETTING

The study was conducted at two Australian stimulant use disorder treatment clinics.

PARTICIPANTS

There were 16 participants: at least 18 years old, MA dependent for at least the preceding 2 years using ICD-10 criteria, reporting use of MA on at least 14 of the preceding 28 days.

INTERVENTIONS

Daily, supervised LDX of 100-250 mg, single-blinded to dose, ascending-descending regimen over 8 weeks (100-250 mg over 4 weeks; followed by 4-week dose reduction regimen, 250-100 mg). Participants were followed through to week 12.

OUTCOMES

Primary outcomes were safety, drug tolerability and regimen completion at the end of week 4. Participants were followed to week 12. Secondary outcomes included: change in MA use; craving; withdrawal; severity of dependence; risk behaviour; change in other substance use; medication acceptability; potential for non-prescription use; adherence and neurocognitive functioning.

RESULTS

Fourteen of 16 participants (87.5%) completed escalation to 250 mg/day. Two participants withdrew from the trial in the first week: one relocated away from the study site, the other self-withdrew due to a possible, known side effect of LDX (agitation). There was one serious adverse event of suicidal ideation which resolved. All other adverse events were mild or moderate in severity and known side effects of LDX. No participant was withdrawn due to adverse events. MA use decreased from a median of 21 days (IQR: 16-23) to 13 days (IQR: 11-17) over the 4-week escalation period (p=0.013).

CONCLUSIONS

LDX at a dose of up to 250 mg/day was safe and well tolerated by study participants, warranting larger trials as a pharmacotherapy for MA dependence.

TRIAL REGISTRATION NUMBER

ACTRN12615000391572.

Pharmacotherapeutic strategies for treating cocaine use disorder-what do we have to offer?

BACKGROUND

Cocaine use contines to be a significant public health problem world-wide. However, despite substantial research efforts, no pharmacotherapies are approved for the treatment of cocaine use disorder (CUD).

ARGUMENT

Studies have identified positive signals for a range of medications for treating CUD. These include long-acting amphetamine formulations, modafinil, topiramate, doxazosin and combined topiramate and mixed amphetamine salts extended-release (MAS-ER). However, valid conclusions about a medication's clinical efficacy require nuanced approaches that take into account behavioural phenotypes of the target population (frequency of use, co-abuse of cocaine and other substances, genetic subgroups, psychiatric comorbidity), variables related to the medication (dose, short-/long-acting formulations, titration speed, medication adherence) and other factors that may affect treatment outcomes. Meta-analyses frequently do not account for these co-varying factors, which contributes to a somewhat nihilistic view on pharmacotherapeutic options for CUD. In addition, the predominant focus on abstinence, which is difficult for most patients to achieve, may overshadow more nuanced therapeutic signals.

CONCLUSION

While there is an emphasis on finding new medications with novel mechanisms of action for treating CUD, currently available medications deserve further investigation based on the existing literature. Evaluating refined metrics of treatment success in well-defined subgroups of patients, and further exploring combination therapies and their synergy with behavioural/psychosocial interventions, are promising avenues to establishing effective therapies for CUD.

Treatment Response Prediction and Individualized Identification of Short-Term Abstinence Methamphetamine Dependence Using Brain Graph Metrics

Background: The abuse of methamphetamine (MA) worldwide has gained international attention as the most rapidly growing illicit drug problem. The classification and treatment response prediction of MA addicts are thereby paramount, in order for effective treatments to be more targeted to individuals. However, there has been limited progress. Methods: In the present study, 43 MA-dependent participants and 38 age- and gender-matched healthy controls were enrolled, and their resting-state functional magnetic resonance imaging data were collected. MA-dependent participants who showed 50% reduction in craving were defined as responders to treatment. The present study used the machine learning method, which is a support vector machine (SVM), to detect the most relevant features for discriminating and predicting the treatment response for MA-dependent participants based on the features extracted from the functional graph metrics. Results: A classifier was able to differentiate MA-dependent subjects from normal controls, with a cross-validated prediction accuracy, sensitivity, and specificity of 73.2% [95% confidence interval (CI) = 71.23-74.17%), 66.05% (95% CI = 63.06-69.04%), and 80.35% (95% CI = 77.77-82.93%), respectively, at the individual level. The most accurate combination of classifier features included the nodal efficiency in the right middle temporal gyrus and the community index in the left precentral gyrus and cuneus. Between these two, the community index in the left precentral gyrus had the highest importance. In addition, the classification performance of the other classifier used to predict the treatment response of MA-dependent subjects had an accuracy, sensitivity, and specificity of 71.2% (95% CI = 69.28-73.12%), 86.75% (95% CI = 84.48-88.92%), and 55.65% (95% CI = 52.61-58.79%), respectively, at the individual level. Furthermore, the most accurate combination of classifier features included the nodal clustering coefficient in the right orbital part of the superior frontal gyrus, the nodal local efficiency in the right orbital part of the superior frontal gyrus, and the right triangular part of the inferior frontal gyrus and right temporal pole of middle temporal gyrus. Among these, the nodal local efficiency in the right temporal pole of the middle temporal gyrus had the highest feature importance. Conclusion: The present study identified the most relevant features of MA addiction and treatment based on SVMs and the features extracted from the graph metrics and provided possible biomarkers to differentiate and predict the treatment response for MA-dependent patients. The brain regions involved in the best combinations should be given close attention during the treatment of MA.

Cabergoline in Treatment of Methamphetamine-Dependent Patients and Its Effect on Serum Level of Glial Cell-Derived Neurotrophic Factor: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

BACKGROUND

Methamphetamine use disorder is an important public health problem, especially in the younger generation, and associated with various psychiatric, cognitive, social, economic, and legal issues. Cabergoline, a drug with dopaminergic properties and long half-life, has been considered for the treatment of stimulant dependence. The systemic use of cabergoline has been shown to increase glial cell-derived neurotrophic factor (GDNF) expression.

OBJECTIVE

In this study, we investigated the effects of cabergoline on the serum level of GDNF and its effect on abstaining from methamphetamine in individuals treated for methamphetamine use disorder.

METHOD

Sixty male subjects with methamphetamine use disorder were randomly assigned to 2 groups receiving cabergoline and placebo, respectively. During a 12-week follow-up, we compared the serum level of GDNF, urine test results for methamphetamine use, and depression scale between the 2 groups.

RESULTS

We found that serum GDNF was lower in subjects who used methamphetamine than healthy subjects (p < 0.0001). However, the serum level of GDNF was not associated with cabergoline use. The rising number of cases testing positive in the placebo group showed a trend resulting in no significant difference between cases testing positive and negative (p = 0.585) at the end of week 12. In the verum group, however, the significantly high number of cases who tested negative - sober - for substances observed in early stages (weeks 7-8) continued to remain significantly higher till the end of the study (p = 0.043), resembling an association between treatment with cabergoline and remaining sober. Although reduced during treatment, recovery from depression was not associated with cabergoline treatment.

CONCLUSION

The findings of this study confirmed the effect of cabergoline in reducing methamphetamine use. However, a serum level of the GDNF increase, as seen in animal studies, was not associated with cabergoline treatment of human subjects. This study was registered at the Iranian Registry of Clinical Trials (TRN:IRCT2015050422077N1, October 06, 2015, https://en.irct.ir/trial/19134).

Adding extended-release methylphenidate to psychological intervention for treatment of methamphetamine dependence: A double-blind randomized controlled trial

Background: Iran has been faced with an emerging epidemic of methamphetamine (MA) use during recent years. No effective pharmacotherapy has been identified for MA treatment; and psychological interventions are the only available effective treatment. The aim of this study is to investigate the efficacy and safety of extended-release methylphenidate (ER-MTP) for the treatment of methamphetamine dependence.

Methods: Sixty-two people with methamphetamine dependence, according to DSM-IV-TR, were randomly assigned to either fixed-dose extended-release methylphenidate (ER-MTP) (60 mg per day) or placebo for 12 weeks. All participants received twice-weekly cognitive behavioral treatment for stimulant dependence. Recent drug use and craving level were measured using weekly rapid urine test and craving visual analogue scale, respectively. The severity of addiction was measured using the Addiction Severity Index at baseline and study completion. Assessment of MA withdrawal was conducted using Amphetamine Withdrawal Questionnaire and Amphetamine Selective Severity Assessment at baseline, day 3, week 1, week 4 and week 12. Depression and high-risk behaviors assessed with the Beck Depression Inventory and the high-risk behavior questionnaire at baseline, weeks 4 and 12 of the study. SPSS software version 22 was used for data analysis and p<0.05 was considered significant.

Results: Percent of weekly MA negative urine tests was not significantly different between groups during the course of the study (p=0.766). Two groups showed similar retention rates. Changes in MA craving, withdrawal, addiction severity, depression and high-risk behaviors were not significantly different between groups. No serious adverse event was observed.

Conclusion: Our finding did not show the superiority of fixed-schedule ER-MTP over placebo when added to an intensive biweekly outpatient psychosocial treatment. Further studies using individually tailored flexible-dose regimes might provide new insights regarding the safety and efficacy of psychostimulant maintenance treatment for MA dependence.

Prescription psychostimulants for the treatment of stimulant use disorder: a systematic review and meta-analysis

RATIONALE

Agonist-based pharmacologic intervention is an accepted approach in treatment of opioid and tobacco use disorders.

OBJECTIVES

We conducted a systematic review and meta-analysis to evaluate usefulness of an agonist approach as treatment of (psycho)stimulant use disorder (PSUD).

METHODS

We reviewed PubMed/Medline, LILACS, and ClinicalTrials.gov databases searching for randomized, double-blind, placebo-controlled, parallel-design studies evaluating outcomes of individuals treated for cocaine- or amphetamine-type substance use disorder. We combined results of all trials that included the following prescription psychostimulants (PPs): modafinil, methylphenidate, or amphetamines (mixed amphetamine salts, lisdexamphetamine, and dextroamphetamine). The combined sample consisted of 2889 patients. Outcomes of interest included the following: drug abstinence (defined as 2-3 weeks of sustained abstinence and the average maximum days of consecutive abstinence), percentage of drug-negative urine tests across trial, and retention in treatment. We conducted random-effects meta-analyses and assessed quality of evidence using the GRADE system.

RESULTS

Thirty-eight trials were included. Treatment with PPs increases rates of sustained abstinence [risk ratio (RR) = 1.45, 95% confidence interval (CI) = (1.10, 1.92)] and duration of abstinence [mean difference (MD) = 3.34, 95% CI = (1.06, 5.62)] in patients with PSUD, particularly those with cocaine use disorder (very low-quality evidence). Prescription amphetamines were particularly efficacious in promoting sustained abstinence in patients with cocaine use disorder [RR = 2.44, 95% CI = (1.66, 3.58)], and higher doses of PPs were particularly efficacious for treatment of cocaine use disorder [RR = 1.95, 95% CI = (1.38, 2.77)] (moderate-quality evidence). Treatment with prescription amphetamines also yielded more cocaine-negative urines [MD = 8.37%, 95% CI = (3.75, 12.98)]. There was no effect of PPs on the retention in treatment.

CONCLUSION

Prescription psychostimulants, particularly prescription amphetamines given in robust doses, have a clinically significant beneficial effect to promote abstinence in the treatment of individuals with PSUD, specifically the population with cocaine use disorder.

Methamphetamine Use: A New Wave in the Opioid Crisis?

BACKGROUND

The ongoing drug crisis in the United States continues to be headlined with numbers of deaths related to opioid overdose. Less known to the public and health care providers is the rise in methamphetamine use, often in conjunction with opioids or adulterated with fentanyl. An old practice with a new twist is the use of methamphetamine in conjunction with an opioid such as heroin.

PURPOSE

Although there are no Food and Drug Administration-approved medications to treat individuals with stimulant use disorders, a review of available studies suggests a few promising medications that may be helpful for patients in early recovery from methamphetamine.

OUTCOME

Some individuals are more likely to respond to medications such as long-acting naltrexone, bupropion, and mirtazapine, who have light-to-moderate use of methamphetamine. Naloxone kits should be considered for all patients who are actively using stimulants because of a high potential of adulterated methamphetamine.

Pharmacological Treatment of Methamphetamine/Amphetamine Dependence: A Systematic Review

BACKGROUND

Stimulant drugs are second only to cannabis as the most widely used class of illicit drug globally, accounting for 68 million past-year consumers. Dependence on amphetamines (AMPH) or methamphetamine (MA) is a growing global concern. Yet, there is no established pharmacotherapy for AMPH/MA dependence. A comprehensive assessment of the research literature on pharmacotherapy for AMPH/MA dependence may inform treatment guidelines and future research directions.

METHODS

We systematically reviewed the peer-reviewed literature via the electronic databases PubMed, EMBASE, CINAHL and SCOPUS for randomised controlled trials reported in the English language examining a pharmacological treatment for AMPH/MA dependence or use disorder. We included all studies published to 19 June 2019. The selected studies were evaluated for design; methodology; inclusion and exclusion criteria; sample size; pharmacological and (if included) psychosocial interventions; length of follow-up and follow-up schedules; outcome variables and measures; results; overall conclusions and risk of bias. Outcome measures were any reported impact of treatment related to AMPH/MA use.

RESULTS

Our search returned 43 studies that met our criteria, collectively enrolling 4065 participants and reporting on 23 individual pharmacotherapies, alone or in combination. Disparate outcomes and measures (n = 55 for the primary outcomes) across studies did not allow for meta-analyses. Some studies demonstrated mixed or weak positive signals (often in defined populations, e.g. men who have sex with men), with some variation in efficacy signals dependent on baseline frequency of AMPH/MA use. The most consistent positive findings have been demonstrated with stimulant agonist treatment (dexamphetamine and methylphenidate), naltrexone and topiramate. Less consistent benefits have been shown with the antidepressants bupropion and mirtazapine, the glutamatergic agent riluzole and the corticotropin releasing factor (CRF-1) antagonist pexacerfont; whilst in general, antidepressant medications (e.g. selective serotonin reuptake inhibitors [SSRIs], tricyclic antidepressants [TCAs]) have not been effective in reducing AMPH/MA use.

CONCLUSIONS

No pharmacotherapy yielded convincing results for the treatment of AMPH/MA dependence; mostly studies were underpowered and had low treatment completion rates. However, there were positive signals from several agents that warrant further investigation in larger scale studies; agonist therapies show promise. Common outcome measures should include change in use days. Future research must address the heterogeneity of AMPH/MA dependence (e.g. coexisting conditions, severity of disorder, differences between MA and AMPH dependence) and the role of psychosocial intervention.

Pharmacotherapeutic strategies for methamphetamine use disorder: mind the subgroups

Introduction: Drug use related deaths are increasing and the lack of effective treatment for psychostimulants can be largely held responsible. Particularly, no pharmacotherapy is approved for methamphetamine (METH) use disorder despite decades of research. Only psychosocial interventions are clinically used, with limited long-term recovery and relapse.Areas covered: This review aims to select and describe the most relevant findings to date. Selected clinical trials were found in PubMed using the following keywords ('methamphetamine') and ('addiction' OR 'withdrawal' OR 'treatment' OR 'pharmacotherapy'). Randomized placebo-controlled trials enrolling treatment-seeking METH-dependent subjects and inherent secondary analysis were included.Expert opinion: Overall, end-of-treatment abstinence, reduced METH use or lower relapse rates were seen on METH dependent subgroups or attained significance only following post hoc analysis, irrespective of the medication tested. For example, light and heavy METH users seem to respond differently to pharmacotherapy. This together with the heterogeneous nature of the METH dependent population strongly suggests that some drugs herein described (e.g. mirtazapine, methylphenidate) should be further tested in clinical trials focused on subgroups. Lastly, objective measures, such as urinalysis, are mandatory to include in clinical trials and early treatment response and/or medication compliance should be carefully monitored and considered as predictors of success/failure.

The cost impact of PCT-guided antibiotic stewardship versus usual care for hospitalised patients with suspected sepsis or lower respiratory tract infections in the US: A health economic model analysis

Background

Procalcitonin is a biomarker that supports clinical decision-making on when to initiate and discontinue antibiotic therapy. Several cost (-effectiveness) analyses have been conducted on Procalcitonin-guided antibiotic stewardship, but none mainly based on US originated data.

Objective

To compare effectiveness and costs of a Procalcitonin-algorithm versus standard care to guide antibiotic prescription for patients hospitalized with a diagnosis of suspected sepsis or lower respiratory tract infection in the US.

Methods

A previously published health economic decision model was used to compare the costs and effects of Procalcitonin-guided care. The analysis considered the societal and hospital perspective with a time horizon covering the length of hospital stay. The main outcomes were total costs per patient, including treatment costs and productivity losses, the number of patients with antibiotic resistance or C.difficile infections, and costs per antibiotic day avoided.

Results

Procalcitonin -guided care for hospitalized patients with suspected sepsis and lower respiratory tract infection is associated with a reduction in antibiotic days, a shorter length of stay on the regular ward and the intensive care unit, shorter duration of mechanical ventilation, and fewer patients at risk for antibiotic resistant or C.difficile infection. Total costs in the Procalcitonin-group compared to standard care were reduced by 26.0% in sepsis and 17.7% in lower respiratory tract infection (total incremental costs of −$11,311 per patient and −$2,867 per patient respectively).

Conclusions

Using a Procalcitonin-algorithm to guide antibiotic use in sepsis and hospitalised lower respiratory tract infection patients is expected to generate cost-savings to the hospital and lower rates of antibiotic resistance and C.difficile infections.

Study of effects of ifenprodil in patients with methamphetamine dependence: Protocol for an exploratory, randomized, double-blind, placebo-controlled trial

Aims

Pharmacotherapy for methamphetamine dependence has not yet been developed in Japan or elsewhere in the world. Ifenprodil is a blocker of G protein‐activated inwardly rectifying potassium channels that play a key role in the mechanism of action of addictive substances. Our aim is to examine the safety, efficacy, and outcomes of ifenprodil for the treatment of methamphetamine dependence in a randomized, double‐blind, placebo‐controlled trial.

Methods

The recruitment of outpatients with methamphetamine dependence began in January 2018. The patients will be randomized into three arms: placebo, 60 mg/d ifenprodil, or 120 mg/d ifenprodil. Placebo or ifenprodil will be taken for 84 days. We will use Cerocral fine granule 4%^® (ifenprodil tartrate). Follow‐up assessments will be conducted for 84 d after the drug administration period. All of the patients will be assessed by self‐administered questionnaires and urine tests. The primary outcome will be the presence or absence of methamphetamine use during the 84‐day administration period in the 120 mg/d ifenprodil and placebo groups. Secondary outcomes will include the number of days and percentage of days of abstinence from methamphetamine use, positive urine for methamphetamine, relapse risk, and drug craving.

Discussion

This study is the first clinical trial of ifenprodil treatment for methamphetamine dependence and is designed as an intervention test with off‐label drug use. The present study is expected to provide evidence of the effects of ifenprodil treatment on methamphetamine dependence.

Trial registry

This trial was registered in the UMIN clinical trial registry (UMIN000030849; date of registration: January 17, 2018).

This study is the first clinical trial of ifenprodil treatment for methamphetamine dependence and is designed as an intervention test with off‐label drug use. The present study is expected to provide evidence of the effects of ifenprodil treatment on methamphetamine dependence.

Pharmacotherapy for amphetamine dependence: A systematic review

BACKGROUND

Demand for treatment for amphetamine use is increasing internationally. Establishing effective pharmacotherapy provides broader treatment options for people who are dependent on amphetamine and may encourage engagement in evidence-based behavioral treatment. This study aimed to identify medicines that have potential in improving treatment outcomes for people who are dependent on amphetamines.

METHODS

Medline, PsycINFO, Embase and the Cochrane Database of Systematic Reviews were searched from 1997 to 2012 and again from 2013 to 2016. Studies on medications for amphetamine/methamphetamine dependence treatment were selected and assessed by two independent researchers. A meta-narrative review approach was used to synthesize results.

RESULTS

A total of 49 studies investigating 20 potential pharmacotherapies were eligible for inclusion. Of these, 35 studies related to 33 level II quality randomized controlled trials (RCTs). Five medications were subject to multiple RCTs. Four of these medicines demonstrated some limited evidence of benefit for reducing amphetamine use: methylphenidate (as reported in three studies), bupropion (in three studies), modafinil (two studies), and naltrexone (one study). Four RCTs of dexamphetamine suggest its benefit on secondary outcomes such as treatment retention, but not for reducing amphetamine use. Six other medicines indicate the potential for efficacy, but the number of studies is too small to draw conclusions.

CONCLUSIONS

No medicine has as yet demonstrated sufficient, consistent evidence of effectiveness to support its use in routine treatment. High study drop-out and poor medication adherence limits the strength of evidence and raises important clinical questions about how to improve treatment engagement and outcomes.

LiMA: a study protocol for a randomised, double-blind, placebo controlled trial of lisdexamfetamine for the treatment of methamphetamine dependence

INTRODUCTION

Methamphetamine dependence is a growing public health concern. There is currently no pharmacotherapy approved for methamphetamine dependence. Lisdexamfetamine (LDX) dimesylate, used in the treatment of attention-deficit hyperactivity disorder and binge eating disorder, has potential as an agonist therapy for methamphetamine dependence, and possible benefits of reduced risk of aberrant use due to its novel formulation.

METHODS AND ANALYSIS

A double-blind randomised controlled trial will be used to evaluate the efficacy of LDX in reducing methamphetamine use. The target sample is 180 participants with methamphetamine dependence of ≥2 years, using ≥14 days out of the previous 28, who have previously attempted but not responded to treatment for methamphetamine use. Participants will be randomly assigned to receive either a 15-week intervention consisting of induction (1 week of 150 mg LDX or placebo), maintenance (12 weeks of 250 mg LDX or placebo) and reduction (1 week of 150 mg LDX or placebo and 1 week of 50 mg LDX or placebo). All participants will be given access to four sessions of cognitive-behavioural therapy as treatment as usual and receive a 4-week follow-up appointment. The primary outcomes are efficacy (change from baseline in days of methamphetamine use by self-report for the last 28 days at week 13 and urinalyses confirmation of methamphetamine use) and safety (treatment-related adverse events). Secondary outcomes are total number of days of self-report methamphetamine use over the 12-week active treatment, longest period of abstinence during treatment period, percentage of achieving ≥21 days abstinence, craving, withdrawal, dependence, retention, bloodborne virus transmission risk behaviour, criminal behaviour, as well measures of abuse liability, physical and mental health, other substance use, cognitive performance, psychosocial functioning, treatment retention and satisfaction. Additionally, the study will assess the cost-effectiveness of LDX relative to the placebo control.

ETHICS AND DISSEMINATION

The study has been approved by the Human Research Ethics Committee of St. Vincent's Hospital, Sydney, Australia (HREC/16/SVH/222). Contact the corresponding author for the full trial protocol.

TRIAL REGISTRATION NUMBER

ACTRN12617000657325; Pre-results.

Methylphenidate doses in Attention Deficit/Hyperactivity Disorder and comorbid substance use disorders

Patients with Attention Deficit/Hyperactivity Disorder (ADHD) and comorbid Substance Use Disorders (SUD) are increasingly being treated with central stimulant medication despite limited evidence for its effectiveness. Lack of longitudinal follow-up studies of dosing and adverse effects has resulted in conflicting treatment guidelines. This study aims to explore whether individuals with ADHD and comorbid SUD are treated with higher stimulant doses than individuals with ADHD only, and whether doses increase over time as a sign of tolerance, a core symptom of addiction. Information on methylphenidate doses for 14 314 Swedish adults, including 4870 individuals with comorbid SUD was obtained through linkages of Swedish national registers between 2006 and 2009. Differences in doses between patients with and without SUD were estimated using logistic regression while a linear regression model calculated time trends in mean doses. Individuals with SUD were prescribed higher methylphenidate doses than those without (OR_day365; 2.12, 95% CI 1.81-2.47: OR_day730 2.65, 95% CI 2.13-3.30). Patients with SUD were, two years after initiating stimulant treatment, prescribed approximately 40% higher doses compared to individuals with ADHD only. The results may suggest a need for increased doses in this population to achieve optimal ADHD symptom control. A tendency towards increasing doses during the first years of treatment, more pronounced in individuals with comorbid SUD, may reflect a reluctance to prescribe adequate doses due to lack of clinical guidelines. Mean doses stabilized after about two years in both groups, which does not lend support to continuously increasing tolerance over time.

Abuse Potential of Oral Phendimetrazine in Cocaine-dependent Individuals: Implications for Agonist-like Replacement Therapy

OBJECTIVES

Phendimetrazine is a prodrug for the monoamine releaser phenmetrazine-a drug with known abuse potential. Preclinical studies suggest that phendimetrazine has limited abuse potential and may have promise as an agonist-like replacement therapy for cocaine dependence. This study evaluated the abuse potential of phendimetrazine in humans.

METHODS

Nine cocaine-dependent individuals (N = 9) were enrolled to investigate the abuse potential of phendimetrazine and d-amphetamine, using a double-blind, placebo-controlled, within-subject design. Subjective and cardiovascular effects of oral phendimetrazine (35, 70, and 105 mg), d-amphetamine (10, 20, and 30 mg), and placebo were assessed in quasi-random order across 8 sessions lasting for approximately 8 hours each.

RESULTS

d-Amphetamine (20 and 30 mg) significantly increased cardiovascular measures in a time and dose-related manner, but phendimetrazine did not systematically alter cardiovascular measures. Although d-amphetamine and phendimetrazine significantly increased ratings indicative of abuse potential (eg, drug liking) and stimulant-like effects relative to placebo, these increases were generally small in magnitude, with phendimetrazine producing significant effects on fewer abuse-related measures and at fewer time points than d-amphetamine.

CONCLUSIONS

These preliminary findings suggest that oral phendimetrazine and d-amphetamine may have limited abuse potential in cocaine-dependent individuals. These findings collectively emphasize that the clinical utility of medications to treat cocaine-use disorders should be weighed carefully against their potential for abuse and diversion, with careful attention paid to evaluating abuse potential in a clinically relevant population of interest. Future studies are needed to further elucidate the potential utility of phendimetrazine as an agonist-like replacement therapy for cocaine dependence.

The neurobiology of addiction: the perspective from magnetic resonance imaging present and future

BACKGROUND AND AIMS

Addiction is associated with severe economic and social consequences and personal tragedies, the scientific exploration of which draws upon investigations at the molecular, cellular and systems levels with a wide variety of technologies. Magnetic resonance imaging (MRI) has been key to mapping effects observed at the microscopic and mesoscopic scales. The range of measurements from this apparatus has opened new avenues linking neurobiology to behaviour. This review considers the role of MRI in addiction research, and what future technological improvements might offer.

METHODS

A hermeneutic strategy supplemented by an expansive, systematic search of PubMed, Scopus and Web of Science databases, covering from database inception to October 2015, with a conjunction of search terms relevant to addiction and MRI. Formal meta-analyses were prioritized.

RESULTS

Results from methods that probe brain structure and function suggest frontostriatal circuitry disturbances within specific cognitive domains, some of which predict drug relapse and treatment response. New methods of processing imaging data are opening opportunities for understanding the role of cerebral vasculature, a global view of brain communication and the complex topology of the cortical surface and drug action. Future technological advances include increases in MRI field strength, with concomitant improvements in image quality.

CONCLUSIONS

The magnetic resonance imaging literature provides a limited but convergent picture of the neurobiology of addiction as global changes to brain structure and functional disturbances to frontostriatal circuitry, accompanied by changes in anterior white matter.

Utility of preclinical drug versus food choice procedures to evaluate candidate medications for methamphetamine use disorder

Substance use disorders are diagnosed as a manifestation of inappropriate behavioral allocation toward abused drugs and away from other behaviors maintained by more adaptive nondrug reinforcers (e.g., money and social relationships). Substance use disorder treatment goals include not only decreasing drug-maintained behavior but also promoting behavioral reallocation toward these socially adaptive alternative reinforcers. Preclinical drug self-administration procedures that offer concurrent access to both drug and nondrug reinforcers provide a translationally relevant dependent measure of behavioral allocation that may be useful for candidate medication evaluation. In contrast to other abused drugs, such as heroin or cocaine, preclinical methamphetamine versus food choice procedures have been a more recent development. We hypothesize that preclinical to clinical translatability would be improved by the evaluation of repeated pharmacological treatment effects on methamphetamine self-administration under a methamphetamine versus food choice procedure. In support of this hypothesis, a literature review suggests strong concordance between preclinical pharmacological treatment effects on methamphetamine versus food choice in nonhuman primates and clinical medication treatment effects on methamphetamine self-administration in human laboratory studies or methamphetamine abuse metrics in clinical trials. In conclusion, this literature suggests preclinical methamphetamine versus food choice procedures may be useful in developing innovative pharmacotherapies for methamphetamine use disorder.

The effects of varenicline on methamphetamine self-administration and drug-primed reinstatement in male rats

Methamphetamine (meth) addiction is a costly burden to both the individual user and society as a whole. Establishing effective pharmacotherapies to treat meth dependence is needed to help solve this health problem. The study reported herein examined the effects of varenicline, a partial α4β2 and full α7 nicotinic acetylcholine receptor agonist, on meth self-administration and reinstatement in male Sprague-Dawley rats. Following indwelling jugular catheter surgery, rats were either trained to self-administer meth or saline on a variable ratio (VR) 3 schedule of reinforcement. Self-administration sessions (2h duration; 19 total sessions) were conducted daily. The effect of varenicline pretreatment on meth and saline self-administration was then determined using a within-study design. All rats received varenicline (0.0, 0.3, 1.0, and 3.0mg/kg) prior to 4 different test sessions. Dose order was randomly assigned and each test was separated by 2 standard self-administration sessions to assess stability of responding. Fifteen extinction sessions (no meth available) followed the last test. Extinction was followed by meth-primed (0.3mg/kg IP) reinstatement tests to examine the effect of varenicline on meth-seeking behavior. All rats again received all doses of varenicline over 4 separate reinstatement tests performed on 4 consecutive days. Varenicline did not alter self-administration of meth or saline. Additionally, the 0.3 and 1.0 doses of varenicline non-specifically increased active lever responding during the reinstatement test sessions. This latter finding suggests that varenicline may increase relapse liability and should not be utilized as pharmacotherapy to treat meth dependence.

Study protocol: a dose-escalating, phase-2 study of oral lisdexamfetamine in adults with methamphetamine dependence

BACKGROUND

The treatment of methamphetamine dependence is a continuing global health problem. Agonist type pharmacotherapies have been used successfully to treat opioid and nicotine dependence and are being studied for the treatment of methamphetamine dependence. One potential candidate is lisdexamfetamine, a pro-drug for dexamphetamine, which has a longer lasting therapeutic action with a lowered abuse potential. The purpose of this study is to determine the safety of lisdexamfetamine in this population at doses higher than those currently approved for attention deficit hyperactivity disorder or binge eating disorder.

METHODS/DESIGN

This is a phase 2 dose escalation study of lisdexamfetamine for the treatment of methamphetamine dependence. Twenty individuals seeking treatment for methamphetamine dependence will be recruited at two Australian drug and alcohol services. All participants will undergo a single-blinded ascending-descending dose regime of 100 to 250 mg lisdexamfetamine, dispensed daily on site, over an 8-week period. Participants will be offered counselling as standard care. For the primary objectives the outcome variables will be adverse events monitoring, drug tolerability and regimen completion. Secondary outcomes will be changes in methamphetamine use, craving, withdrawal, severity of dependence, risk behaviour and other substance use. Medication acceptability, potential for non-prescription use, adherence and changes in neurocognition will also be measured.

DISCUSSION

Determining the safety of lisdexamfetamine will enable further research to develop pharmacotherapies for the treatment of methamphetamine dependence.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ACTRN12615000391572 Registered 28^th April 2015.

Efficacy and safety of psychostimulants for amphetamine and methamphetamine use disorders: a systematic review and meta-analysis

BACKGROUND

Amphetamine and methamphetamine use disorders are associated with severe health and social consequences. No pharmacological therapy has been approved for the treatment of these disorders. Psychostimulants can act as maintenance-like therapies for managing substance use among these patients. The aim of this study is to evaluate the literature examining the efficacy and safety of psychostimulant agents for increasing abstinence and treatment retention among patients with amphetamine and methamphetamine use disorders.

METHODS

We searched MEDLINE, EMBASE, PsycInfo, Cochrane Central, and CINAHL from inception to August 2016. Selection of studies, data extraction, and risk of bias assessment were conducted independently by two reviewers. We conducted meta-analyses to provide a pooled summary estimate for included trials and report the review according to PRISMA guidelines.

RESULTS

We identified and selected 17 studies with 1387 participants. Outcome reporting across trials was inconsistent, and the overall quality of evidence was very low due to high risk of bias and indirectness. A meta-analysis of five trials (642 participants) found no effect of psychostimulants for end-of-study abstinence (odds ratio = 0.97, 95% confidence interval 0.65 to 1.45). Additionally, the pooled estimate from 14 studies (1184 participants) showed no effect of psychostimulants for treatment retention (odds ratio = 1.20, 95% confidence interval = 0.91 to 1.58). The incidence of serious adverse events did not differ between intervention and placebo groups based on qualitative reports from trials.

CONCLUSIONS

Quantitative analyses showed no effect of psychostimulants for sustained abstinence or treatment retention. We also identified the need for more rigorous studies in this research area with clinician and patient important outcomes.

Tryptophan for the sleeping disorder and mental symptom of new-type drug dependence: A randomized, double-blind, placebo-controlled trial

INTRODUCTION

New-type drugs are popular with adolescents and could lead to psychiatry disorders, but no medications have been proven to be effective for these disorders of new-type drug dependence. We aimed to evaluate the efficacy of tryptophan on sleeping disorders and mental symptoms in detoxified individuals with new-type drug dependence.

METHODS

This randomized, placebo-controlled trial included 80 detoxified individuals with new-type drug dependence, recruited successively from a Compulsory Residential Drug Abstinence Institution in Wuhan, China, from April 2012 to November 2012. Eligible participants were randomly allocated to be treated with tryptophan (1000 mg/d, n = 40) or placebo (n = 40) for 2 weeks. The sleeping disorders and mental symptoms were assessed using Athens Insomnia Scale and Symptom Check-List-90 at baseline and 2 weeks. Results were analyzed according to the "intention-to-treat" approach.

RESULTS

Forty-five participants completed the 2-week study, 24 in the tryptophan group and 21 in the placebo group. There were no statistically significant differences in baseline characteristics between groups and the treatment adherence was similar between groups. The reduction in the Athens Insomnia Scale score in the tryptophan group was significantly greater than that in the placebo group (P = 0.017). However, no significant differences were found in Symptom Check-List-90 scores (either by individual dimension or the overall score) between groups (all P > 0.05). The frequency of adverse events was similar and no serious adverse events were reported during the study.

CONCLUSION

Tryptophan was unlikely to be effective for mental symptoms, but could alleviate sleep disorders in short term among detoxified individuals with new-type drug dependence. Future large-scale trials are required to confirm findings from this study.

Regulation of the Dopamine and Vesicular Monoamine Transporters: Pharmacological Targets and Implications for Disease

Dopamine (DA) plays a well recognized role in a variety of physiologic functions such as movement, cognition, mood, and reward. Consequently, many human disorders are due, in part, to dysfunctional dopaminergic systems, including Parkinson's disease, attention deficit hyperactivity disorder, and substance abuse. Drugs that modify the DA system are clinically effective in treating symptoms of these diseases or are involved in their manifestation, implicating DA in their etiology. DA signaling and distribution are primarily modulated by the DA transporter (DAT) and by vesicular monoamine transporter (VMAT)-2, which transport DA into presynaptic terminals and synaptic vesicles, respectively. These transporters are regulated by complex processes such as phosphorylation, protein-protein interactions, and changes in intracellular localization. This review provides an overview of 1) the current understanding of DAT and VMAT2 neurobiology, including discussion of studies ranging from those conducted in vitro to those involving human subjects; 2) the role of these transporters in disease and how these transporters are affected by disease; and 3) and how selected drugs alter the function and expression of these transporters. Understanding the regulatory processes and the pathologic consequences of DAT and VMAT2 dysfunction underlies the evolution of therapeutic development for the treatment of DA-related disorders.

Identification of Treatment Targets in a Genetic Mouse Model of Voluntary Methamphetamine Drinking

Methamphetamine has powerful stimulant and euphoric effects that are experienced as rewarding and encourage use. Methamphetamine addiction is associated with debilitating illnesses, destroyed relationships, child neglect, violence, and crime; but after many years of research, broadly effective medications have not been identified. Individual differences that may impact not only risk for developing a methamphetamine use disorder but also affect treatment response have not been fully considered. Human studies have identified candidate genes that may be relevant, but lack of control over drug history, the common use or coabuse of multiple addictive drugs, and restrictions on the types of data that can be collected in humans are barriers to progress. To overcome some of these issues, a genetic animal model comprised of lines of mice selectively bred for high and low voluntary methamphetamine intake was developed to identify risk and protective alleles for methamphetamine consumption, and identify therapeutic targets. The mu opioid receptor gene was supported as a target for genes within a top-ranked transcription factor network associated with level of methamphetamine intake. In addition, mice that consume high levels of methamphetamine were found to possess a nonfunctional form of the trace amine-associated receptor 1 (TAAR1). The Taar1 gene is within a mouse chromosome 10 quantitative trait locus for methamphetamine consumption, and TAAR1 function determines sensitivity to aversive effects of methamphetamine that may curb intake. The genes, gene interaction partners, and protein products identified in this genetic mouse model represent treatment target candidates for methamphetamine addiction.

The effects of varenicline on methamphetamine self-administration and drug-primed reinstatement in female rats

While research has revealed heightened vulnerability to meth addiction in women, preclinical models rarely use female subjects when investigating meth seeking and relapse. The goal of the present study was to examine the effects of varenicline (Chantix(®)), a partial α4β2 and full α7 nicotinic acetylcholine receptor agonist, on meth self-administration and reinstatement in female rats. Sprague-Dawley rats were surgically implanted with an indwelling jugular catheter. Half of the rats were then trained to self-administer meth (0.056 mg/kg/infusion) on a variable ratio 3 schedule of reinforcement; the other half earned intravenous saline during daily, 2h sessions. When responding stabilized, varenicline (0.0, 0.3, 1.0, 3.0mg/kg) was tested to determine how it altered meth taking. Varenicline was probed on 4 test days; each test separated by 2 standard self-administration sessions to assure responding remained stable. Following this testing was 15 extinction sessions. Twenty-four hours after the last extinction session were four consecutive days of meth-primed reinstatement. The same 4 doses of varenicline were examined to determine how it altered reinstatement triggered by 0.3mg/kg meth (IP). Rats readily self-administered meth. The higher doses of varenicline did not affect meth-taking in a specific fashion as active lever pressing was also slightly reduced in rats that has access to saline in the self-administration phase. Female rats displayed robust meth-primed reinstatement. Notably, the lower doses of varenicline increased meth-primed reinstatement. This amplified susceptibility to reinstatement (i.e., relapse) may be an impediment for the use of varenicline as a therapeutic to treat meth use disorder.

Effects of 7-day continuous D-amphetamine, methylphenidate, and cocaine treatment on choice between methamphetamine and food in male rhesus monkeys

BACKGROUND

Methamphetamine addiction is a significant public health problem for which no Food and Drug Administration-approved pharmacotherapies exist. Preclinical drug vs. food choice procedures have been predictive of clinical medication efficacy in the treatment of opioid and cocaine addiction. Whether preclinical choice procedures are predictive of candidate medication effects for other abused drugs, such as methamphetamine, remains unclear. The present study aim was to determine continuous 7-day treatment effects with the monoamine releaser d-amphetamine and the monoamine uptake inhibitor methylphenidate on methamphetamine vs. food choice. In addition, 7-day cocaine treatment effects were also examined.

METHODS

Behavior was maintained under a concurrent schedule of food delivery (1-g pellets, fixed-ratio 100 schedule) and methamphetamine injections (0-0.32mg/kg/injection, fixed-ratio 10 schedule) in male rhesus monkeys (n=4). Methamphetamine choice dose-effect functions were determined daily before and during 7-day periods of continuous intravenous treatment with d-amphetamine (0.01-0.1mg/kg/h), methylphenidate (0.032-0.32mg/kg/h), or cocaine (0.1-0.32mg/kg/h).

RESULTS

During saline treatment, increasing methamphetamine doses resulted in a corresponding increase in methamphetamine vs. food choice. Continuous 7-day treatments with d-amphetamine, methylphenidate or cocaine did not significantly attenuate methamphetamine vs. food choice up to doses that decreased rates of operant responding. However, 0.1mg/kg/h d-amphetamine did eliminate methamphetamine choice in two monkeys.

CONCLUSIONS

The present subchronic treatment results support the utility of preclinical methamphetamine choice to evaluate candidate medications for methamphetamine addiction. Furthermore, these results confirm and extend previous results demonstrating differential pharmacological mechanisms between cocaine choice and methamphetamine choice.

Psychostimulants: Basic and Clinical Pharmacology

Substance use disorder, and particularly psychostimulant use disorder, has considerable socioeconomic burden globally. The psychostimulants include several chemical classes, being derivatives of benzoylecgonine, phenethylamine, phenylpropanolamine, or aminoaryloxazoline. Psychostimulant drugs activate the brain reward pathways of the mesoaccumbal system, and continued use leads to persistent neuroplastic and dysfunctional changes of a variety of structures involved in learning and memory, habit-forming learning, salience attribution, and inhibitory control. There are a variety of neurochemical and neurobehavioral changes in psychostimulant addiction, for example, dopaminergic, glutamatergic, serotonergic (5-HT-ergic), and γ-amino butyric acid (GABA) changes have all noted. In this chapter, we will review pharmacological changes associated with psychostimulant use and abuse in humans and animals, and on the basis of the best characterized and most widely abused psychostimulants (amphetamines, cocaine) discuss why use transitions into abuse and review basic science and clinical strategies that might assist in treating psychostimulant abuse.

Sustained-release methylphenidate in methamphetamine dependence treatment: a double-blind and placebo-controlled trial

BACKGROUND

The objective of this randomized, double-blind, placebo-controlled study was to evaluate the efficacy of sustained-release methylphenidate (MPH-SR) in treatment of methamphetamine dependence.

METHODS

Fifty-six individuals who met DSM-IV-TR criteria for methamphetamine dependence participated in this 10-week trial. The participants were randomly allocated into two groups and received 18 to 54 mg/day sustained-released methylphenidate or placebo for 10 weeks. Craving was evaluated by a visual analogue craving scale every week. Urinary screening test for methamphetamine was carried out each week. The Beck Depression Inventory-II (BDI-II) was used to monitor participant depressive symptoms at baseline and bi-weekly during the treatment period.

RESULTS

At the end of the trial, the MPH-SR group was less methamphetamine positive compared to the placebo group and the difference was significant (p = 0.03). By the end of the study, MPH-SR group showed significantly less craving scores compared to the placebo group [MD (95% CI) = -10.28(0.88-19.18), t(54) = 2.19, p = 0.03]. There was greater improvement in the depressive symptoms scores in the intervention group compared to the placebo group [MD (95% CI) =2.03(0.31-3.75), t (54) =2.37, p = 0.02].

CONCLUSION

Sustained-released methylphenidate was safe and well tolerated among active methamphetamine users and significantly reduced methamphetamine use, craving and depressive symptoms.

TRIAL REGISTRATION

IRCT201202281556N38.

Methamphetamine self-administration in humans during D-amphetamine maintenance

Agonist replacement may be a viable treatment approach for managing stimulant use disorders. This study sought to determine the effects of D-amphetamine maintenance on methamphetamine self-administration in stimulant using human participants. We predicted that D-amphetamine maintenance would reduce methamphetamine self-administration. Eight participants completed the protocol, which tested 2 D-amphetamine maintenance conditions in counterbalanced order (0 and 40 mg/d). Participants completed 4 experimental sessions under each maintenance condition in which they first sampled 1 of 4 doses of intranasal methamphetamine (0, 10, 20, or 30 mg). Participants then had the opportunity to respond on a computerized progressive-ratio task to earn portions of the sampled methamphetamine dose. Subject-rated drug effect and physiological measures were completed at regular intervals prior to and after sampling methamphetamine. Methamphetamine was self-administered as an orderly function of dose regardless of the maintenance condition. Methamphetamine produced prototypical subject-rated effects on 12 items of the drug-effects questionnaires, 8 of which were attenuated by D-amphetamine maintenance (eg, increased ratings were attenuated on items such as Any Effect, Like Drug, and Willing to Take Again on the Drug Effect Questionnaire). Methamphetamine produced significant increases in systolic blood pressure, which were attenuated by D-amphetamine maintenance compared to placebo maintenance. Methamphetamine was well tolerated during D-amphetamine maintenance and no adverse events occurred. Although D-amphetamine attenuated some subject-rated effects of methamphetamine, the self-administration results are concordant with those of clinical trials showing that D-amphetamine did not reduce methamphetamine use. Unique pharmacological approaches may be needed for treating amphetamine use disorders.