Pilot randomized controlled study of dexamphetamine substitution for amphetamine dependence

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.

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.

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.

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.

Treatment for Substance Use Disorder With Co-Occurring Mental Illness

Substance use disorder is a highly prevalent condition, leading to significant morbidity, mortality, and burden on the health care system. Substance use disorders are overrepresented among individuals with a mental illness. The term "dual diagnosis" was introduced by the World Health Organization in the mid-1990s and refers to the co-occurrence of a substance use disorder with mental illness-a more recently used term is "co-occurring disorders." In the past decade, substantial progress has been made toward expanding psychotherapeutic and pharmacotherapeutic treatments for treating co-occurring disorders. Yet management remains a challenge among clinicians and has been a source of confusion and considerable controversy. This review describes the epidemiology and treatment of co-occurring disorders, with a focus on major depressive disorder, anxiety disorders, and attention-deficit hyperactivity disorder. Substance use may make diagnosis of the underlying psychiatric condition difficult, and a period of abstinence may be necessary. Findings from efficacy studies of medications used to treat co-occurring disorders are reviewed, as are results of preliminary studies of newer treatments, such as topiramate, ketamine, noninvasive brain stimulation, and deep brain stimulation. Treatment recommendations that combine medications and psychosocial interventions are summarized.

Human Drug Discrimination: Elucidating the Neuropharmacology of Commonly Abused Illicit Drugs

Drug-discrimination procedures empirically evaluate the control that internal drug states have over behavior. They provide a highly selective method to investigate the neuropharmacological underpinnings of the interoceptive effects of drugs in vivo. As a result, drug discrimination has been one of the most widely used assays in the field of behavioral pharmacology. Drug-discrimination procedures have been adapted for use with humans and are conceptually similar to preclinical drug-discrimination techniques in that a behavior is differentially reinforced contingent on the presence or absence of a specific interoceptive drug stimulus. This chapter provides a basic overview of human drug-discrimination procedures and reviews the extant literature concerning the use of these procedures to elucidate the underlying neuropharmacological mechanisms of commonly abused illicit drugs (i.e., stimulants, opioids, and cannabis) in humans. This chapter is not intended to review every available study that used drug-discrimination procedures in humans. Instead, when possible, exemplary studies that used a stimulant, opioid, or Δ9-tetrahydrocannabinol (the primary psychoactive constituent of cannabis) to assess the discriminative-stimulus effects of drugs in humans are reviewed for illustrative purposes. We conclude by commenting on the current state and future of human drug-discrimination research.

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.

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.

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.

English and American Drug Clients' Views of the Acceptability, Advantages, and Disadvantages of Treatment and Harm Reduction Interventions

Although drug abusers present to clinics and drop-in centers requesting various treatments and harm reduction interventions, clinicians and administrators have little direct empirical evidence of the degree to which clients find various therapies acceptable or the perceived advantages and disadvantages of specific interventions. A structured interview was administered to 48 male and female outpatient or detoxification ward clients in Nottingham, England, and 40 female residential treatment program clients in Northwest Ohio, to assess the acceptability of and related attitudes regarding a broad range of interventions. Large proportions of respondents in both samples, and especially in the English sample, reported somewhat or complete acceptance of various abstinence-oriented treatments and harm reduction interventions for those still taking drugs. Respondents also discriminated among these interventions, as evidenced by differing levels of acceptance of many and outright rejection of other interventions. Although there were differences in acceptance and experience of the specific interventions between the two samples, respondents in both countries provided balanced appraisals of the advantages and disadvantages of each intervention.

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.

Future pharmacological treatments for substance use disorders

Substance use disorders represent a serious public health and social issue worldwide. Recent advances in our understanding of the neurobiological basis of the addictive processes have led to the development of a growing number of pharmacological agents to treat addictions. Despite this progress, there are no approved pharmacological treatments for cocaine, methamphetamine and cannabis addiction. Moving treatment development to the next stage will require novel ways of approaching substance use disorders. One such novel approach is to target individual vulnerabilities, such as cognitive function, sex differences and psychiatric comorbidities. This review provides a summary of promising pharmacotherapies for alcohol, opiate, stimulant and nicotine addictions. Many medications that target positive and negative reinforcement of drugs, as well as individual vulnerabilities to addiction, are in different phases of development. Clinical trials testing the efficacy of these medications for substance use disorder are warranted.

Agonist replacement for stimulant dependence: a review of clinical research

Stimulant use disorders are an unrelenting public health concern worldwide. Agonist replacement therapy is among the most effective strategies for managing substance use disorders including nicotine and opioid dependence. The present paper reviewed clinical data from human laboratory self-administration studies and clinical trials to determine whether agonist replacement therapy is a viable strategy for managing cocaine and/or amphetamine use disorders. The extant literature suggests that agonist replacement therapy may be effective for managing stimulant use disorders, however, the clinical selection of an agonist replacement medication likely needs to be based on the pharmacological mechanism of the medication and the stimulant abused by patients. Specifically, dopamine releasers appear most effective for reducing cocaine use whereas dopamine reuptake inhibitors appear most effective for reducing amphetamine use.

Irish adolescents with ADHD and comorbid substance use disorder

Objectives:

To examine the literature for drug treatment of attention deficit hyperactivity disorder (ADHD) in adolescents with co-occurring substance use disorder (SUD), the challenges posed by this, and make recommendations taking into account current trend in Ireland.

Methods:

Articles published from 1992-2008 were identified using OVID-MEDLINE search using the search terms attention deficit hyperactivity disorder and substance use disorder. Studies cited include review articles, epidemiological studies, experimental researches, open and controlled trials of drugs in ADHD with comorbid SUD and clinical guidelines. No non-English language papers were included.

Results:

Thirty-six studies were examined. A number of the papers reported on the link between ADHD and SUD, that they frequently co-occur, and there is evidence that treating ADHD can reduce the risk of future SUD. Some of the studies reviewed demonstrated the safety and effectiveness of ADHD medication on the ADHD symptoms but less so on the SUD. Concerns around stimulant abuse and diversion are valid. Although there is no current evidence of frequent diversion of ADHD medications in Ireland, this practice is prevalent in the US. Consequently psychiatrists should remain vigilant to the possibility of such diversions and take measures to address them if identified.

Conclusions:

The available evidence suggests that medication is not hazardous in ADHD comorbid with SUD. Pharmacological treatment of ADHD, following consideration of potential risks and benefits, is justified in the presence of SUD. Both methylphenidate and atomoxetine can be used. Stabilisation of serious SUD before pharmacotherapy is preferable, and it is advisable to provide psychological treatment to address SUD in these patients.

Pharmacotherapeutics for substance-use disorders: a focus on dopaminergic medications

INTRODUCTION

Illicit substance-use is a substantial public health concern, contributing over $150 billion in costs annually to Americans. A complex disease, a substance-use disorder affects neural circuits involved in reinforcement, motivation, learning and memory, and inhibitory control.

AREAS COVERED

The modulatory influence of dopamine in mesocorticolimbic circuits contributes to encoding the primary reinforcing effects of substances and numerous studies suggest that aberrant signaling within these circuits contributes to the development of a substance-use disorder in some individuals. Decades of research focused on the clinical development of medications that directly target dopamine receptors has led to recent studies of agonist-like dopaminergic treatments for stimulant-use disorders and, more recently, cannabis-use disorder. Human studies evaluating the efficacy of dopaminergic agonist-like medications to reduce reinforcing effects and substance-use provide some insight into the design of future pharmacotherapy trials. A search of PubMed using specific brain regions, medications, and/or the terms 'dopamine', 'cognition', 'reinforcement', 'cocaine', 'methamphetamine', 'amphetamine', 'cannabis', 'treatment/pharmacotherapy', 'addiction/abuse/dependence' identified articles relevant to this review.

EXPERT OPINION

Conceptualization of substance-use disorders and their treatment continues to evolve. Current efforts increasingly focus on a strategy fostering combination pharmacotherapies that target multiple neurotransmitter systems.

Efficacy of psychostimulant drugs for amphetamine abuse or dependence

BACKGROUND

Amphetamine dependence is a public health problem with medical, psychiatric, cognitive, legal and socioeconomic consequences. To date, no pharmacological treatment has been approved for this disorder, and psychotherapy remains the mainstay of treatment. In recent years, psychostimulants have been investigated as a possible replacement therapy.

OBJECTIVES

To evaluate the efficacy and safety of psychostimulant medications for amphetamine abuse or dependence. The influences of type of drug, type of dependence, comorbid disorders, clinical trial risk of bias and publication of data were also studied.

SEARCH METHODS

Relevant trials were searched in the following sources: PubMed (January 1966 to 6 June 2012), EMBASE (January 1988 to 6 June 2012), CENTRAL (The Cochrane Library, Issue 5 of 12, May 2012), PsycINFO (January 1985 to 6 June 2012) and the Specialised Register of the Cochrane Drug and Alcohol Group (June 2012). We also searched the reference lists of retrieved trials, the list of studies citing the included trials and the main electronic registers of ongoing trials (ClinicalTrials.gov, International Clinical Trials Registry Platform and EU Clinical Trials Register). Finally, we contacted investigators to request information about unpublished trials. Searches included non-English language literature.

SELECTION CRITERIA

All randomised, placebo-controlled, parallel-group clinical trials investigating the efficacy or safety of psychostimulants for amphetamine dependence or abuse conducted in an outpatient setting.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

Eleven studies were included in the review (791 participants). Studied psychostimulants included dexamphetamine, bupropion, methylphenidate and modafinil. No significant differences were found between psychostimulants and placebo for any of the studied efficacy outcomes. Overall retention in studies was low (50.4%). Psychostimulants did not reduce amphetamine use (mean difference (MD) -0.26, 95% confidence interval (CI) -0.85 to 0.33) or amphetamine craving (MD 0.07, 95% CI -0.44 to 0.59) and did not increase sustained abstinence (relative risk (RR) 1.12, 95% CI 0.84 to 1.49). The proportion of adverse events inducing dropout was similar for psychostimulants and placebo (risk difference (RD) 0.01, 95% CI -0.03 to 0.04). The main findings did not change in any subgroup analysis.

AUTHORS' CONCLUSIONS

Results of this review do not support the use of psychostimulant medications at the tested doses as a replacement therapy for amphetamine abuse or dependence. Future research could change this conclusion, as the numbers of included studies and participants are limited and information on relevant outcomes, such as efficacy according to the severity of dependence or craving, is still missing.

Extended-release methylphenidate for treatment of amphetamine/methamphetamine dependence: a randomized, double-blind, placebo-controlled trial

AIMS

To assess the efficacy of methylphenidate as a substitution therapy for amphetamine/methamphetamine dependence in Finland and New Zealand.

DESIGN

Parallel-group, double-blind, randomized placebo-controlled trial.

SETTING

Out-patient care.

PARTICIPANTS

Amphetamine-/methamphetamine-dependent, aged 16-65 years.

MEASUREMENTS

The primary outcome measure was presence/absence of amphetamine/methamphetamine in urine samples collected twice weekly. Secondary measures included treatment adherence, alterations in craving scores and self-reported use. Primary analysis was by intention-to-treat (ITT). The study drug, methylphenidate (as Concerta(®) ), was up-titrated over 2 weeks to a maximum dose of 54 mg daily and continued for a further 20 weeks. Doses were given under daily supervision at the clinics.

FINDINGS

Seventy-nine participants were randomized (40 methylphenidate; 39 placebo); 76 received allocated treatment and 27 completed the trial. ITT analysis (n = 78) showed no statistically significant difference in the percentage of positive urines between the methylphenidate and placebo arms (odds ratio: 0.95, 95% confidence interval: 0.83-1.08). However, there was a significant difference (P < 0.05) between the active and placebo arms in retention, the placebo arm displaying a significantly lower retention from 6 weeks that persisted until the end of the trial.

CONCLUSIONS

The trial failed to replicate earlier findings suggesting that methylphenidate was superior to placebo. The low retention rate confounded the ability to draw firm conclusions about efficacy. The higher retention rate was observed in the methylphenidate arm. Any replication of this work would need to consider alternatives to the rigid clinic attendance criteria, and consider an increased dose.

Methamphetamine use: a comprehensive review of molecular, preclinical and clinical findings

Methamphetamine (MA) is a highly addictive psychostimulant drug that principally affects the monoamine neurotransmitter systems of the brain and results in feelings of alertness, increased energy and euphoria. The drug is particularly popular with young adults, due to its wide availability, relatively low cost, and long duration of psychoactive effects. Extended use of MA is associated with many health problems that are not limited to the central nervous system, and contribute to increased morbidity and mortality in drug users. Numerous studies, using complementary techniques, have provided evidence that chronic MA use is associated with substantial neurotoxicity and cognitive impairment. These pathological effects of the drug, combined with the addictive properties of MA, contribute to a spectrum of psychosocial issues that include medical and legal problems, at-risk behaviors and high societal costs, such as public health consequences, loss of family support and housing instability. Treatment options include pharmacological, psychological or combination therapies. The present review summarizes the key findings in the literature spanning from molecular through to clinical effects.

Pharmacotherapy of amphetamine-type stimulant dependence: an update

ISSUES

Methamphetamine- or amphetamine-type stimulants are the second most frequently used illicit drug worldwide, second only to cannabis. Behavioural treatments are efficacious, but their impact is limited underscoring the need for other treatment options, notably, pharmacotherapy.

APPROACH

A review of randomised controlled trials of pharmacotherapies for methamphetamine- or amphetamine-type stimulants was performed using PubMed and Google Scholar databases. Evidence for efficacy of medications is reported.

KEY FINDINGS

Clinical trials have yielded no broadly effective pharmacotherapy. Promising signals have been observed for methylphenidate, naltrexone, bupropion and mirtazapine in subgroups of patients in reducing stimulant use (e.g. patients with less severe dependence at baseline and men who have sex with men), though none has produced an unambiguous, replicable signal of efficacy.

IMPLICATIONS

Problems in Phase II trials, including high dropout rates, missing data and a lack of agreement on outcomes, complicate efforts to find a broadly effective pharmacotherapy for amphetamine-type stimulant disorders. Efforts to address these problems include calls for better validation of pharmacological target exposure, receptor binding and functional modulation. As well, there is a need for agreement in using findings from preclinical and early phases of the medication development process for selecting better pharmacotherapy candidates.

CONCLUSION

After over 20 years of efforts worldwide to develop a broadly effective medication for dependence on methamphetamine- or amphetamine-type stimulants, no candidate has emerged. This highlights the need for new compounds, consistent and stringent research methods, better integration between preclinical and clinical stages of medication development, and improved collaboration between government, industry and researchers.

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

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

BAP updated guidelines: evidence-based guidelines for the pharmacological management of substance abuse, harmful use, addiction and comorbidity: recommendations from BAP

The British Association for Psychopharmacology guidelines for the treatment of substance abuse, harmful use, addiction and comorbidity with psychiatric disorders primarily focus on their pharmacological management. They are based explicitly on the available evidence and presented as recommendations to aid clinical decision making for practitioners alongside a detailed review of the evidence. A consensus meeting, involving experts in the treatment of these disorders, reviewed key areas and considered the strength of the evidence and clinical implications. The guidelines were drawn up after feedback from participants. The guidelines primarily cover the pharmacological management of withdrawal, short- and long-term substitution, maintenance of abstinence and prevention of complications, where appropriate, for substance abuse or harmful use or addiction as well management in pregnancy, comorbidity with psychiatric disorders and in younger and older people.

Distinguishing symptoms of ADHD from other psychiatric disorders in the adult primary care setting

Attention-deficit/hyperactivity disorder (ADHD) is frequently misdiagnosed or undiagnosed in adults. Owing to the relatively recent recognition of adult ADHD as a valid mental disorder and its overlapping symptomatology with other conditions, primary care physicians often fail to screen for ADHD in patients who present with inattention, impulsivity, and hyperactivity. A substantial proportion of adults with ADHD also have psychiatric comorbidities. Physicians need to recognize the ways in which ADHD symptoms are expressed in adults and distinguish them from symptoms of other disorders, including mood, anxiety, and substance abuse disorders.

Subjective and physiological effects of acute intranasal methamphetamine during d-amphetamine maintenance

RATIONALE

Methamphetamine abuse and dependence are significant public-health concerns. Behavioral therapies are effective for reducing methamphetamine use. However, many patients enrolled in behavioral therapies are unable to achieve significant periods of abstinence, suggesting other strategies like pharmacotherapy are needed.

OBJECTIVES

This experiment determined the subjective and physiological effects of intranasal methamphetamine during D: -amphetamine maintenance in eight non-treatment-seeking stimulant-dependent participants. We predicted D: -amphetamine maintenance would attenuate the acute subjective effects of intranasal methamphetamine. We also predicted intranasal methamphetamine would be well tolerated during D: -amphetamine maintenance.

METHODS

After at least 7 days of maintenance on sustained-release D: -amphetamine (0 and 45 mg/day), participants were administered ascending doses of intranasal methamphetamine (0, 2.5, 5, 10, and 20 mg) across two experimental sessions. Intranasal methamphetamine doses were separated by 90 min.

RESULTS

Intranasal methamphetamine produced prototypical subjective and physiological effects (e.g., increased ratings of Like Drug; increased heart rate, blood pressure, and body temperature). The acute effects of intranasal methamphetamine were significantly diminished during D: -amphetamine maintenance relative to placebo maintenance.

CONCLUSIONS

These results are concordant with those of clinical trials and provide further support for the use of agonist replacement therapy to manage methamphetamine dependence. Additional research in humans is needed to determine the effectiveness of D: -amphetamine under different experimental conditions that more closely reflect use in the natural environment (e.g., higher methamphetamine doses) and behavioral arrangements that are predictive of pharmacotherapy effectiveness (e.g., drug self-administration).

Neuroscience of behavioral and pharmacological treatments for addictions

Although substantial advances have been made in behavioral and pharmacological treatments for addictions, moving treatment development to the next stage may require novel ways of approaching addictions, particularly ways based on new findings regarding the neurobiological underpinnings of addictions that also assimilate and incorporate relevant information from earlier approaches. In this review, we first briefly review theoretical and biological models of addiction and then describe existing behavioral and pharmacologic therapies for the addictions within this framework. We then propose new directions for treatment development and targets that are informed by recent evidence regarding the heterogeneity of addictions and the neurobiological contributions to these disorders.

A randomized, placebo-controlled trial of sustained-release dextroamphetamine for treatment of methamphetamine addiction

Sixty treatment-seeking individuals with methamphetamine (MA) dependence entered a randomized, placebo-controlled, double-blind clinical trial of oral dextroamphetamine (d-AMP) as a replacement therapy for MA dependence. The subjects took 60 mg sustained-release d-AMP for 8 weeks, during which time they received eight 50-min sessions of individual psychotherapy. Adverse events and urine toxicology for MA were assessed two times a week. There were no serious adverse events. Urine samples containing <1,000 ng/ml of MA were classified as negative for MA. The MA-negative scores in the d-AMP group (3.1 ± SD 4.6) were no higher than those in the placebo group (3.3 ± SD 5.3; P > 0.05). However, withdrawal and craving scores were significantly lower in the d-AMP group (P < 0.05 for both). Although subjects taking d-AMP did not reduce their use of MA, the significant reductions observed in withdrawal and craving scores in this group support the need for further exploration of d-AMP as a pharmacologic intervention for MA dependence, possibly at higher doses.

Pharmacological approaches to methamphetamine dependence: a focused review

Methamphetamine dependence is a serious worldwide public health problem with major medical, psychiatric, socioeconomic and legal consequences. Various neuronal mechanisms implicated in methamphetamine dependence have suggested several pharmacological approaches. A literature search from a range of electronic databases (PubMed, EMBASE, PsycInfo, the NIDA research monograph index and the reference list of clinicaltrials.gov) was conducted for the period from January 1985 to October 2009. There were no restrictions on the identification or inclusion of studies in terms of publication status, language and design type. A variety of medications have failed to show efficacy in clinical trials, including a dopamine partial agonist (aripiprazole), GABAergic agents (gabapentin) and serotonergic agents (SSRI, ondansetron, mirtazapine). Three double-blind placebo-controlled trials using modafinil, bupropion and naltrexone have shown positive results in reducing amphetamine or methamphetamine use. Two studies employing agonist replacement medications, one with d-amphetamine and the other with methylphenidate, have also shown promise. Despite the lack of success in most studies to date, increasing efforts are being made to develop medications for the treatment of methamphetamine dependence and several promising agents are targets of further research.

Effects of chronic d-amphetamine administration on the reinforcing strength of cocaine in rhesus monkeys

RATIONALE

Agonist medications have been proven effective in treating opioid and nicotine dependence; results from clinical studies suggest that the indirect dopamine agonist d-amphetamine may reduce cocaine abuse. In preclinical studies, chronic d-amphetamine treatment decreased ongoing cocaine self-administration.

OBJECTIVES

The present study extended previous results by determining effects of chronic d-amphetamine treatment on the reinforcing strength of cocaine under conditions in which access to cocaine was suspended during d-amphetamine treatment.

METHODS

Daily operant conditioning sessions consisted of morning access to food pellets delivered under a 50-response fixed-ratio schedule and evening access to cocaine (0.005-0.48 mg/kg per injection, i.v.) under a progressive-ratio schedule. After responding maintained by 0.045 mg/kg per injection cocaine stabilized, self-administration sessions were suspended and d-amphetamine (0.01-0.1 mg/kg per hr, i.v.) was administered continuously for 5 days. On the following day, d-amphetamine treatment was discontinued and daily self-administration sessions resumed.

RESULTS

Following termination of d-amphetamine treatment, food- and cocaine-maintained responding was decreased in a dose-related manner. Decreases in the reinforcing strength of cocaine were larger and lasted longer than effects on food reinforcement. However, cocaine self-administration was unaltered if 6 days elapsed between discontinuation of d-amphetamine treatment and the next cocaine self-administration session.

CONCLUSIONS

The necessity of a self-administration session in the presence of d-amphetamine suggests that the protracted decrease in cocaine self-administration may be a manifestation of behavioral tolerance. Regarding treatment of cocaine dependence, data suggest that prolonged d-amphetamine treatment may be necessary to produce a sustained reduction in the reinforcing effects of cocaine.

Agonist-like pharmacotherapy for stimulant dependence: preclinical, human laboratory, and clinical studies

A variety of natural and synthetic agents have long been used for stimulant properties, with nontherapeutic use producing multiple waves of stimulant abuse and dependence. The multitude of effects of stimulants exist on continua, and accordingly, here we characterize stimulant abuse/dependence and candidate pharmacotherapies in this manner. Behavioral therapy and medications have been investigated for treatment of stimulant abuse/dependence. Effectiveness of some behavioral interventions has been demonstrated. Most medications studied have been found to lack efficacy. However, an expanding literature supports use of agonist-like medications to treat stimulant abuse/dependence, a strategy effective for nicotine and opiate dependence. The agonist-like conceptualization for stimulant dependence posits that medications with properties similar to that of the abused drug, but possessing lesser abuse liability, will normalize neurochemistry and stabilize behavior, thus reducing drug use. Data suggest use of a range of medications, from l-dopa/carbidopa to amphetamine preparations, depending on the severity of use. This report reviews preclinical, human laboratory, and clinical trial data supporting the agonist-like approach, including risks and benefits. Future directions for development of agonist-like medications are also discussed.

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

AIM

To investigate the safety and efficacy of once-daily supervised oral administration of sustained-release dexamphetamine in people dependent on methamphetamine.

DESIGN

Randomized, double-blind, placebo-controlled trial.

PARTICIPANTS

Forty-nine methamphetamine-dependent drug users from Drug and Alcohol Services South Australia (DASSA) clinics.

INTERVENTION

Participants were assigned randomly to receive up to 110 mg/day sustained-release dexamphetamine (n = 23) or placebo (n = 26) for a maximum of 12 weeks, with gradual reduction of the study medication over an additional 4 weeks. Medication was taken daily under pharmacist supervision.

MEASUREMENTS

Primary outcome measures included treatment retention, measures of methamphetamine consumption (self-report and hair analysis), degree of methamphetamine dependence and severity of methamphetamine withdrawal. Hair samples were analysed for methamphetamine using liquid chromatography-mass spectrometry.

FINDINGS

Treatment retention was significantly different between groups, with those who received dexamphetamine remaining in treatment for an average of 86.3 days compared with 48.6 days for those receiving placebo (P = 0.014). There were significant reductions in self-reported methamphetamine use between baseline and follow-up within each group (P < 0.0001), with a trend to a greater reduction among the dexamphetamine group (P = 0.086). Based on hair analysis, there was a significant decrease in methamphetamine concentration for both groups (P < 0.0001). At follow-up, degree of methamphetamine dependence was significantly lower in the dexamphetamine group (P = 0.042). Dexamphetamine maintenance was not associated with serious adverse events.

CONCLUSIONS

The results of this preliminary study have demonstrated that a maintenance pharmacotherapy programme of daily sustained-release amphetamine dispensing under pharmacist supervision is both feasible and safe. The increased retention in the dexamphetamine group, together with the general decreases in methamphetamine use, degree of dependence and withdrawal symptom severity, provide preliminary evidence that this may be an efficacious treatment option for methamphetamine dependence.

Cognitive enhancement as a pharmacotherapy target for stimulant addiction

BACKGROUND

No medications have been proven to be effective for cocaine and methamphetamine addiction. Attenuation of drug reward has been the main strategy for medications development, but this approach has not led to effective treatments. Thus, there is a need to identify novel treatment targets in addition to the brain reward system.

AIM

To propose a novel treatment strategy for stimulant addiction that will focus on medications enhancing cognitive function and attenuating drug reward.

METHODS

Pre-clinical and clinical literature on potential use of cognitive enhancers for stimulant addiction pharmacotherapy was reviewed.

RESULTS AND CONCLUSIONS

Cocaine and methamphetamine users show significant cognitive impairments, especially in attention, working memory and response inhibition functions. The cognitive impairments seem to be predictive of poor treatment retention and outcome. Medications targeting acetylcholine and norepinephrine are particularly well suited for enhancing cognitive function in stimulant users. Many cholinergic and noradrenergic medications are on the market and have a good safety profile and low abuse potential. These include galantamine, donepezil and rivastigmine (cholinesterase inhibitors), varenicline (partial nicotine agonist), guanfacine (alpha(2)-adrenergic agonist) and atomoxetine (norepinephrine transporter inhibitor). Future clinical studies designed optimally to measure cognitive function as well as drug use behavior would be needed to test the efficacy of these cognitive enhancers for stimulant addiction.

A review of psychosocial interventions for amphetamine use

There are clear signs that amphetamine use is increasing in Australia and internationally, yet there are few services that offer amphetamine-specific interventions. This review examines the evidence for the use of psychosocial interventions for amphetamine users. The literature is very limited in the number of well-conducted, controlled studies, but the evidence available suggests that cognitive-behavioural therapy appears to be current best practice. Motivational interviewing has been recommended as a strategy to assist those ambivalent for treatment. There is also some evidence that contingency management is effective while clients are in treatment. The effectiveness of other types of intervention is not well supported. The literature is particularly hindered by a paucity of well-conducted studies among primary amphetamine users. Recommendations about appropriate interventions for use in clinical settings are offered and directions for future research are considered.

Pharmacotherapies for problematic psychostimulant use: a review of current research

This review summarizes the current status of clinical research on pharmacotherapies for problematic psychostimulant use. The use of psychostimulants, including amphetamine, cocaine and ecstasy, is increasingly a feature of Australian life as is the presentation of patients with psychostimulant disorders. A lack of experience, resources and treatment options have constrained the response of treatment services to such problems. Despite extensive research, particularly in the area of cocaine, no pharmacotherapy has been proven effective in the management of psychostimulant disorders. The harms associated with problematic psychostimulant use warrant further controlled research in innovative approaches integrated with psychosocial interventions.

Pharmacotherapy of methamphetamine addiction: an update

Methamphetamine dependence is a serious public health problem worldwide for which there are no approved pharmacological treatments. Psychotherapy is still the mainstay of treatment; however, relapse rates are high. The search for effective pharmacological treatment has intensified in the last decade. This review will highlight progress in pharmacological interventions to treat methamphetamine dependence as well as explore new pharmacological targets. Published data from clinical trials for stimulant addiction were searched using PubMed and summarized, as well as highlights from a recent symposium on methamphetamine pharmacotherapy presented at the ISAM 2006 meeting, including interim analysis data from an ongoing D-amphetamine study in Australia. Early pilot data are encouraging for administering D-amphetamine and methylphenidate as treatment for heavy amphetamine users. Abilify at 15 mg/day dose increased amphetamine use in an outpatient pilot study. Sertraline, ondansetron, baclofen, tyrosine, and imipramine were ineffective in proof-of-concept studies. Development of pharmacotherapy for methamphetamine dependence is still in an early stage. Data suggesting D-amphetamine and methylphenidate as effective pharmacotherapy for methamphetamine addiction will need to be confirmed by larger trials. Preclinical data suggest that use of GVG, CB1 antagonist, and lobeline are also promising therapeutic strategies.

Use of stimulants to treat cocaine and methamphetamine abuse

The concept of using stimulants to treat cocaine and methamphetamine dependence is largely based on the "replacement" therapy model that has shown efficacy for treating nicotine and opiate dependence. Although results have been mixed, some evidence supports using stimulant medication to reduce cocaine use. There are not enough data to date to determine the efficacy of stimulants for methamphetamine dependence. Drawbacks of stimulants as treatments include the potential for abuse of the treatment, which necessitates careful screening and monitoring of patients. Possible reasons for efficacy of stimulants include enhancement of monoamine function dysregulated by chronic cocaine or methamphetamine use. Newer medications that enhance dopamine function but lack the abuse potential of older stimulants are being studied. It is hoped that these medications will provide safe, effective treatment for cocaine and methamphetamine dependence, but more research on this topic is needed.

Pharmacologic mechanisms of crystal meth

Crystal meth is a form of the stimulant drug methamphetamine that, when smoked, can rapidly achieve high concentrations in the brain. Methamphetamine causes the release of the neurotransmitters dopamine, norepinephrine and serotonin and activates the cardiovascular and central nervous systems. The levels of dopamine are low in the brain of some drug users, but whether this represents neuronal loss is uncertain. The areas of the brain involved in methamphetamine addiction are unknown but probably include the dopamine-rich striatum and regions that interact with the striatum. There is no medication approved for the treatment of relapses of methamphetamine addiction; however, potential therapeutic agents targeted to dopamine and nondopamine (e.g., opioid) systems are in clinical testing.

A placebo-controlled trial of mirtazapine for the management of methamphetamine withdrawal

INTRODUCTION AND AIMS

As an antidepressant with sedative and anxiolytic properties, mirtazapine may be an appropriate pharmacotherapy for methamphetamine withdrawal. This study sought to examine whether mirtazapine improves retention and alleviates methamphetamine withdrawal symptoms in an out-patient setting.

DESIGN AND METHODS

An out-patient double-blind, randomised placebo-controlled trial of mirtazapine for the treatment of methamphetamine withdrawal was conducted (15 mg nocte for 2 days, 30 mg nocte for 12 days). Both groups were offered narrative therapy counselling. Measures recorded on days 0, 3, 7, 14 and 35 included: treatment retention, Amphetamine Cessation Symptoms Assessment, the Athens Insomnia Scale, the Brief Symptom Inventory, the Depression-Anxiety-Stress Scale (DASS), Severity of Dependence scale and the Opiate Treatment Index Drug Use subscale.

RESULTS

Thirty-one participants were recruited (18 placebo, 13 mirtazapine) and 52% completed the 2-week medication phase. No significant differences between the mirtazapine and placebo groups in retention, or any symptom measure were observed, except greater DASS-anxiety and longer sleep duration were measured at baseline among the mirtazapine group.

DISCUSSION AND CONCLUSIONS

Results suggest that mirtazapine does not facilitate retention or recruitment in out-patient methamphetamine withdrawal treatment, although recruitment may have been insufficient to identify a significant treatment effect. The potential role of narrative therapy for methamphetamine dependent patients deserves further exploration.

The principles of agonist pharmacotherapy for psychostimulant dependence

ISSUES

Psychostimulant dependence is a chronic, relapsing condition which is highly treatment refractory. No medications to date have been any more successful than placebo in reducing psychostimulant use in dependent patients. Agonist strategies have attracted limited attention.

APPROACH

Successful examples of agonist pharmacotherapy in the treatment of heroin and nicotine dependence are first considered. Agonist pharmacological approaches to the treatment of psychostimulant dependence are then examined, based on the dopamine receptor agonist and indirect dopamine agonist strategies. Finally, the potential extension of the concept of agonist pharmacotherapy to include the novel non-amphetamine-type stimulant, modafinil, is discussed.

CONCLUSIONS

Agonist approaches appear to be viable with risks outweighed by benefits in carefully selected, monitored and motivated patients. On the other hand, the effectiveness of indirect agonists such as dexamphetamine and methylphenidate are not established. Further research is required to determine optimal treatment models (whether maintenance or withdrawal), effective safe dosages and duration (short or long term).

A preliminary randomized, double-blind, placebo-controlled study of the safety and efficacy of ondansetron in the treatment of methamphetamine dependence

Methamphetamine dependence is an increasing public health problem in the United States. No efficacious medication for methamphetamine dependence has been developed. As ondansetron, a 5-HT3 receptor antagonist and modulator of cortico-mesolimbic dopamine function, has been shown to reduce some of the rewarding effects of d-amphetamine in animal and human laboratory studies, we decided to test whether it would be superior to placebo at reducing methamphetamine use. In a preliminary, multi-site, randomized, double-blind, 8-wk controlled trial, 150 methamphetamine-dependent men and women received ondansetron (0.25 mg, 1 mg, or 4 mg b.i.d.) or placebo. Participants were assessed on several measures of methamphetamine use including urine methamphetamine level up to three times per week. As a psychosocial adjunct to the medication condition, cognitive behavioural therapy also was administered three times per week. Ondansetron was well tolerated and was less likely than placebo to be associated with serious adverse events. Nevertheless, none of the ondansetron doses was superior to placebo at decreasing any of the measures of methamphetamine use, withdrawal, craving, or clinical severity of methamphetamine dependence. Our preliminary results do not support the utility of ondansetron, at the doses tested, as a treatment for methamphetamine dependence. These findings should be viewed in light of the possibility that a less intensive cognitive behavioural therapy regimen might have yielded more positive results in this initial phase II trial exploring for the efficacy of ondansetron.

Controlling illegal stimulants: a regulated market model

Prohibition of illegal drugs is a failed social policy and new models of regulation of these substances are needed. This paper explores a proposal for a post-prohibition, public health based model for the regulation of the most problematic drugs, the smokable and injectable stimulants. The literature on stimulant maintenance is explored. Seven foundational principles are suggested that could support this regulatory model of drug control that would reduce both health and social problems related to illegal stimulants. Some details of this model are examined and the paper concludes that drug policies need to be subject to research and based on evidence.

Biological treatments for amfetamine dependence : recent progress

Amfetamine abuse has grown into a worldwide epidemic. Methamfetamine, a derivative of amfetamine made from readily accessible chemicals, has plagued the US since the 1960s, with an alarming recent surge in the numbers of those meeting the criteria for amfetamine abuse and dependence. We review this problem using a computerised literature search (PubMed 1964-2007) to summarise knowledge from animal and human studies about treatments for amfetamine dependence, while exploring the potential of pharmacogenetics to help uncover new treatment targets. Several promising therapeutic targets have come from animal models of reward, drug-taking behaviour and withdrawal. Although preclinical and selected clinical results have been promising, clinical studies have yielded inconsistent results. To improve these outcomes, pharmacogenetic studies may be used to identify candidate alleles that predict therapeutic response. Exciting preclinical findings and a steady progression of clinical results offer hope for the development of a treatment for amfetamine dependence.

Treatment strategies for co-occurring ADHD and substance use disorders

Attention-deficit hyperactivity disorder (ADHD) is a common co-occurring mental disorder among patients with substance use disorders (SUD). Clinicians must be cognizant of the complicated nature of diagnosis and treatment of ADHD when comorbid with SUD. Pharmacotherapy remains the mainstay of treatment for ADHD, although complementary psychotherapeutic approaches have been developed. Psychostimulant medications are the most commonly used medications to treat ADHD, but many clinicians are reluctant to prescribe stimulants to patients with SUD. Recommendations for treatment planning and clinical management for patients with co-occurring ADHD and SUD are discussed.

Acute d-amphetamine pretreatment does not alter stimulant self-administration in humans

Recent clinical research indicates that d-amphetamine is effective in treating cocaine and methamphetamine dependence. There is concern, however, with the use of d-amphetamine as a pharmacotherapy because acute administration of d-amphetamine decreases inhibition in cocaine-using individuals and may increase drug-taking behavior. The purpose of the present experiment was to determine whether acute d-amphetamine pretreatment would alter the reinforcing, subject-rated, and cardiovascular effects of d-amphetamine. To this end, 7 human volunteers first sampled doses of oral d-amphetamine (0, 8, and 16 mg). These doses engender moderate drug taking and were selected to avoid a ceiling or floor effect. Volunteers were then allowed to self-administer these sampled doses using a modified progressive-ratio procedure in two sessions in which they received pretreatment with either 0 or 15 mg oral d-amphetamine 2 h prior to completing the modified progressive-ratio procedure. d-Amphetamine produced prototypical stimulant-like effects (e.g., increased ratings of stimulated, elevated blood pressure) and maintained responding on the modified progressive-ratio schedule. Pretreatment with 15 mg oral d-amphetamine also produced prototypical stimulant-like effects, but failed to alter break points for d-amphetamine on the modified progressive-ratio procedure relative to placebo pretreatment. These results indicate that acute d-amphetamine pretreatment does not increase stimulant self-administration.

Therapeutic challenges of attention-deficit hyperactivity disorder with substance use disorders

Attention-deficit hyperactivity disorder (ADHD), a common neuropsychiatric disorder of childhood, adolescence and adulthood, is frequently comorbid with substance use disorders (SUDs) in both adolescents and adults. This paper will provide an overview of the relationship between ADHD and SUDs and discuss the primary areas of therapeutic challenge in the treatment of individuals with comorbid ADHD and SUDs, including the diagnosis of ADHD in populations with SUDs, selecting appropriate agents for use and prevention of abuse and/or diversion of the therapeutic pharmacological agents used in ADHD treatment. The authors will also provide a discussion on the future of research and treatment in this area and key issues for clinicians.

The methamphetamine epidemic: implications for HIV prevention and treatment

Methamphetamine and related amphetamine compounds are among the most commonly used illicit drugs, with over 35 million users worldwide. In the United States, admissions for methamphetamine treatment have increased dramatically over the past 10 years. Methamphetamine use is prevalent among persons with HIV infection and persons at risk for HIV, particularly among men who have sex with men. In addition to being associated with increased sexual risk behavior, methamphetamine causes significant medical morbidity, including neurologic deficits, cardiovascular compromise, dental decay, and skin infections, all of which may be worsened in the presence of HIV/AIDS. Methamphetamine use may also result in decreased medication adherence, particularly during "binging" episodes. Behavioral counseling remains the standard of treatment for methamphetamine dependence, although the effectiveness of most counseling interventions has not been rigorously tested. Pharmacologic and structural interventions may prove valuable additional interventions to reduce methamphetamine use.