A screening trial of amantadine as a medication for cocaine dependence

Pharmacological Treatments for Cocaine Craving: What Is the Way Forward? A Systematic Review

BACKGROUND

cocaine craving is a core feature of cocaine use disorder and remains a critical challenge for abstinence and relapse prevention. This review summarizes the anti-craving efficacy of pharmacotherapies tested for cocaine use disorder, in the context of randomized-controlled clinical trials.

OBJECTIVES

we assessed the databases of the U.S. National Library of Medicine, Google Scholar, and PsycINFO, without date restrictions up to August 2022, to identify relevant studies.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

we included double-blinded randomized-controlled trials investigating pharmacotherapies for cocaine craving and/or cocaine use disorder whose outcomes included cocaine craving.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two authors screened studies' titles and abstracts for inclusion, and both read all the included studies. We systematically gathered information on the following aspects of each study: title; author(s); year of publication; sample size; mean age; sample characteristics; study set-ting; whether participants were treatment-seeking; study design; craving measures; study interventions; drop-out rates; and other relevant outcomes.

RESULTS

Overall, we appraised 130 clinical trials, including 8137 participants. We further considered the drugs from the studies that scored equal to or greater than six points in the quality assessment. There was a correlation between craving and cocaine use outcomes (self-reports, timeline follow-back or urinary benzoylecgonine) in the vast majority of studies. In the short-term treatment, acute phenylalanine-tyrosine depletion, clonidine, fenfluramine, meta-chlorophenylpiperazine (m-CPP) and mecamylamine presented promising effects. In the long term, amphetamine, biperiden, carbamazepine, lisdexamfetamine, lorcaserin, methamphetamine, mirtazapine, pioglitazone, progesterone, guanfacine, levodopa, nefazodone presented promising anti-craving effects. Unfortunately, the highly tested medications were not successful in most of the trials, as follows: propranolol in the short term; amantadine, aripiprazole, bromocriptine, citicoline, ketamine, modafinil, olanzapine, topiramate in the long term. The remaining 52 medications had no positive anti-craving outcomes.

LIMITATIONS

Our review was limited by high heterogeneity of craving assessments across the studies and by a great range of pharmacotherapies. Further, the majority of the studies considered abstinence and retention in treatment as the main outcomes, whereas craving was a secondary outcome and some of the studies evaluated patients with cocaine use disorder with comorbidities such as opioid or alcohol use disorder, schizophrenia, bipolar disorder or attention deficit hyperactivity. Lastly, most of the studies also included non-pharmacological treatments, such as counseling or psychotherapy.

CONCLUSIONS

There is a direct association between craving and cocaine use, underscoring craving as an important treatment target for promoting abstinence among persons with cocaine use disorder. Clonidine, fenfluramine and m-CPP showed to be promising medications for cocaine craving in the short-term treatment, and amphetamine, biperiden, carbamazepine, lisdexamfetamine, lorcaserin, methamphetamine, mirtazapine, pioglitazone, progesterone, guanfacine, levodopa, nefazodone in the long-term treatment.

Comparison of Treatments for Cocaine Use Disorder Among Adults: A Systematic Review and Meta-analysis

IMPORTANCE

In the US and the United Kingdom, cocaine use is the second leading cause of illicit drug overdose death. Psychosocial treatments for cocaine use disorder are limited, and no pharmacotherapy is approved for use in the US or Europe.

OBJECTIVE

To compare treatments for active cocaine use among adults.

DATA SOURCES

PubMed and the Cochrane Database of Systematic Reviews were searched for clinical trials published between December 31, 1995, and December 31, 2017.

STUDY SELECTION

This meta-analysis was registered on Covidence.org (study 8731) on December 31, 2015. Clinical trials were included if they (1) had the term cocaine in the article title; (2) were published between December 31, 1995, and December 31, 2017; (3) were written in English; (4) enrolled outpatients 18 years or older with active cocaine use at baseline; and (5) reported treatment group size, treatment duration, retention rates, and urinalysis results for the presence of cocaine metabolites. A study was excluded if (1) more than 25% of participants were not active cocaine users or more than 80% of participants had negative test results for the presence of cocaine metabolites at baseline and (2) it reported only pooled urinalysis results indicating the presence of multiple substances and did not report the specific proportion of positive test results for cocaine metabolites. Multiple reviewers reached criteria consensus. Of 831 records screened, 157 studies (18.9%) met selection criteria and were included in the analysis.

DATA EXTRACTION AND SYNTHESIS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline. Search results were imported from PubMed XML into Covidence.org then Microsoft Excel. Data extraction was completed in 2 iterations to ensure fidelity. Analyses included a multilevel random-effects model, a multilevel mixed-effects meta-regression model, and sensitivity analyses. Treatments were clustered into 11 categories (psychotherapy, contingency management programs, placebo, opioids, psychostimulants, anticonvulsants, dopamine agonists, antidepressants, antipsychotics, miscellaneous medications, and other therapies). Missing data were imputed using multiple imputation by chained equations. The significance threshold for all analyses was P = .05. Data were analyzed using the metafor and mice packages in R software, version 3.3.2 (R Foundation for Statistical Computing). Data were analyzed from January 1, 2018, to February 28, 2021.

MAIN OUTCOMES AND MEASURES

The primary outcome was the intention-to-treat logarithm of the odds ratio (OR) of having a negative urinalysis result for the presence of cocaine metabolites at the end of each treatment period compared with baseline. The hypothesis, which was formulated after data collection, was that no treatment category would have a significant association with objective reductions in cocaine use.

RESULTS

A total of 157 studies comprising 402 treatment groups and 15 842 participants were included. Excluding other therapies, the largest treatment groups across all studies were psychotherapy (mean [SD] number of participants, 40.04 [36.88]) and contingency management programs (mean [SD] number of participants, 37.51 [25.51]). Only contingency management programs were significantly associated with an increased likelihood of having a negative test result for the presence of cocaine (OR, 2.13; 95% CI, 1.62-2.80), and this association remained significant in all sensitivity analyses.

CONCLUSIONS AND RELEVANCE

In this meta-analysis, contingency management programs were associated with reductions in cocaine use among adults. Research efforts and policies that align with this treatment modality may benefit those who actively use cocaine and attenuate societal burdens.

Evaluation of the "Pipeline" for Development of Medications for Cocaine Use Disorder: A Review of Translational Preclinical, Human Laboratory, and Clinical Trial Research

Cocaine use disorder is a persistent public health problem for which no widely effective medications exist. Self-administration procedures, which have shown good predictive validity in estimating the abuse potential of drugs, have been used in rodent, nonhuman primate, and human laboratory studies to screen putative medications. This review assessed the effectiveness of the medications development process regarding pharmacotherapies for cocaine use disorder. The primary objective was to determine whether data from animal and human laboratory self-administration studies predicted the results of clinical trials. In addition, the concordance between laboratory studies in animals and humans was assessed. More than 100 blinded, randomized, fully placebo-controlled studies of putative medications for cocaine use disorder were identified. Of the 64 drugs tested in these trials, only 10 had been examined in both human and well-controlled animal laboratory studies. Within all three stages, few studies had been conducted for each drug and when multiple studies had been conducted conclusions were sometimes contradictory. Overall, however, there was good concordance between animal and human laboratory results when the former assessed chronic drug treatment. Although only seven of the ten reviewed drugs showed fully concordant results across all three types of studies reviewed, the analysis revealed several subject-related, procedural, and environmental factors that differ between the laboratory and clinical trial settings that help explain the disagreement for other drugs. The review closes with several recommendations to enhance translation and communication across stages of the medications development process that will ultimately speed the progress toward effective pharmacotherapeutic strategies for cocaine use disorder.

Barriers to Condom Use: Results for Men and Women Enrolled in HIV Risk Reduction Trials in Outpatient Drug Treatment

HIV transmission often occurs through heterosexual high-risk sex. Even in the era of HIV combination prevention, promoting condom use, and understanding condom barriers, remain priorities, especially among substance-dependent individuals. Men and women (N=729) in outpatient drug treatment participated in a five-session gender-specific risk reduction group or one-session HIV Education group. Condom barriers (Motivation, Partner-related, Access/Availability, Sexual experience) were assessed at baseline and 6-month follow-up. Completing either intervention was associated with fewer motivation and partner-related barriers. Among women, reductions in motivation and sexual experience barriers were associated with less sexual risk with primary partners. Condom barriers are important to gender-specific HIV prevention; given limited resources, brief interventions maximizing active components are needed.

Dopamine agonists for the treatment of cocaine dependence

BACKGROUND

Cocaine misuse is a disorder for which no pharmacological treatment of proven efficacy exists. Advances in neurobiology could guide future medication development.

OBJECTIVES

To investigate the efficacy and acceptability of dopamine agonists alone or in combination with any psychosocial intervention for the treatment of of people who misuse cocaine.

SEARCH METHODS

We run the search on 12 January 2015. We searched the Cochrane Drugs and Alcohol Group (CDAG) Specialized Register, PubMed, EMBASE, CINAHL, PsycINFO, ICTRP, clinicaltrials.gov and screened reference lists.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing dopamine agonists alone or associated with psychosocial intervention with placebo, no treatment or other pharmacological interventions.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

Twenty four studies, including 2147 participants, met the inclusion criteria. Comparing any dopamine agonist versus placebo, we found no differences for any of the outcomes considered: dropout (moderate quality of evidence), abstinence (low quality of evidence), severity of dependence (low quality of evidence), adverse events (moderate quality of evidence). This was also observed when single dopamine agonists were compared against placebo. Comparing amantadine versus antidepressants, we found low quality of evidence that antidepressants performed better for abstinence (RR 0.25, 95% CI 0.12 to 0.53) based on two studies with 44 participants. No differences were found for dropout or adverse events, for both moderate quality of evidence.The major flaws of the included studies concerned selection bias because most studies did not report information about sequence generation (80%) and allocation concealment methods (86%): half of the included studies were judged at unclear risk of performance bias and 62.5% at unclear risk of detection bias for what concerns subjective outcomes.

AUTHORS' CONCLUSIONS

Current evidence from RCTs does not support the use of dopamine agonists for treating cocaine misuse. This absence of evidence may leave to clinicians the alternative of balancing the possible benefits against the potential adverse effects of the treatment. Even the potential benefit of combining a dopamine agonist with a more potent psychosocial intervention, which was suggested by the previous Cochrane Review (Soares 2003), is not supported by the results of this Cochrane Review update.

The prescription of addiction medications after implementation of chronic care management for substance dependence in primary care

People with addictive disorders commonly do not receive efficacious medications. Chronic care management (CCM) is designed to facilitate delivery of effective therapies. Using data from the CCM group in a trial testing its effectiveness for addiction (N=282), we examined factors associated with the prescription of addiction medications. Among participants with alcohol dependence, 17% (95% CI 12.0-22.1%) were prescribed alcohol dependence medications. Among those with drug dependence, 9% (95% CI 5.5-12.6%) were prescribed drug dependence medications. Among those with opioids as a substance of choice, 15% (95% CI 9.3-20.9%) were prescribed opioid agonist therapy. In contrast, psychiatric medications were prescribed to 64% (95% CI 58.2-69.4%). Absence of co-morbid drug dependence was associated with prescription of alcohol dependence medications. Lower alcohol addiction severity and recent opioid use were associated with prescription of drug dependence medications. Better understanding of infrequent prescription of addiction medications, despite a supportive clinical setting, might inform optimal approaches to delivering addiction medications.

Achieving cannabis cessation -- evaluating N-acetylcysteine treatment (ACCENT): design and implementation of a multi-site, randomized controlled study in the National Institute on Drug Abuse Clinical Trials Network

Despite recent advances in behavioral interventions for cannabis use disorders, effect sizes remain modest, and few individuals achieve long-term abstinence. One strategy to enhance outcomes is the addition of pharmacotherapy to complement behavioral treatment, but to date no efficacious medications targeting cannabis use disorders in adults through large, randomized controlled trials have been identified. The National Institute on Drug Abuse Clinical Trials Network (NIDA CTN) is currently conducting a study to test the efficacy of N-acetylcysteine (NAC) versus placebo (PBO), added to contingency management, for cannabis cessation in adults (ages 18-50). This study was designed to replicate positive findings from a study in cannabis-dependent adolescents that found greater odds of abstinence with NAC compared to PBO. This paper describes the design and implementation of an ongoing 12-week, intent-to-treat, double-blind, randomized, placebo-controlled study with one follow-up visit four weeks post-treatment. Approximately 300 treatment-seeking cannabis-dependent adults will be randomized to NAC or PBO across six study sites in the United States. The primary objective of this 12-week study is to evaluate the efficacy of twice-daily orally-administered NAC (1200 mg) versus matched PBO, added to contingency management, on cannabis abstinence. NAC is among the first medications to demonstrate increased odds of abstinence in a randomized controlled study among cannabis users in any age group. The current study will assess the cannabis cessation efficacy of NAC combined with a behavioral intervention in adults, providing a novel and timely contribution to the evidence base for the treatment of cannabis use disorders.

Predictors and moderators of outcomes of HIV/STD sex risk reduction interventions in substance abuse treatment programs: a pooled analysis of two randomized controlled trials

Background

The objective of the current study was to examine predictors and moderators of response to two HIV sexual risk interventions of different content and duration for individuals in substance abuse treatment programs.

Methods

Participants were recruited from community drug treatment programs participating in the National Institute on Drug Abuse Clinical Trials Network (CTN). Data were pooled from two parallel randomized controlled CTN studies (one with men and one with women) each examining the impact of a multi-session motivational and skills training program, in comparison to a single-session HIV education intervention, on the degree of reduction in unprotected sex from baseline to 3- and 6- month follow-ups. The findings were analyzed using a zero-inflated negative binomial (ZINB) model.

Results

Severity of drug use (p < .01), gender (p < .001), and age (p < .001) were significant main effect predictors of number of unprotected sexual occasions (USOs) at follow-up in the non-zero portion of the ZINB model (men, younger participants, and those with greater severity of drug/alcohol abuse have more USOs). Monogamous relationship status (p < .001) and race/ethnicity (p < .001) were significant predictors of having at least one USO vs. none (monogamous individuals and African Americans were more likely to have at least one USO). Significant moderators of intervention effectiveness included recent sex under the influence of drugs/alcohol (p < .01 in non-zero portion of model), duration of abuse of primary drug (p < .05 in non-zero portion of model), and Hispanic ethnicity (p < .01 in the zero portion, p < .05 in the non-zero portion of model).

Conclusion

These predictor and moderator findings point to ways in which patients may be selected for the different HIV sexual risk reduction interventions and suggest potential avenues for further development of the interventions for increasing their effectiveness within certain subgroups.

Reducing Sexual Risk Behaviors for HIV/STDs in Women with Alcohol Use Disorders

Objective: A pilot randomized clinical trial (RCT) examined effectiveness of HIV/STD Safer Sex Skills Building + Alcohol (SSB+A) intervention for women with Alcohol Use Disorders (AUDs) in a residential treatment setting. Method: After randomizing thirty-six women with AUDs and reporting having intercourse with a male partner in the past 180 days to SSB+A or HE (standard HIV/STD education) groups, rates of penetrative intercourse with and without condoms at 60 day and 180 day follow-up were compared between SSB+A or HE groups. Results: There was a significant difference in mean number of sex acts with condoms between SSB+A and HE groups over time. Specifically, SSB+A and HE groups did not differ at 60 day follow-up, but at 180 day follow-up, mean sex acts with condoms among SSB+A group was significantly higher than HE. Conclusion: Pilot study findings affirm the effectiveness of the SSB+A in reducing sexual risk behaviors of AUD women and support the need for further research, testing the SSB+A intervention in a larger sample of women and across different treatment modalities. The present study also illustrates the critical link between practice and use of a step by step model of intervention research.

A double-blind, placebo-controlled trial of modafinil for cocaine dependence

This is a randomized, double-blind, placebo-controlled study of modafinil treatment for cocaine dependence. Patients (N = 210) who were actively using cocaine at baseline were randomized to 8 weeks of modafinil (0 mg/day, 200 mg/day, or 400 mg/day) combined with once-weekly cognitive-behavioral therapy. Our primary efficacy measure was cocaine abstinence, based on urine benzoylecgonine (BE) levels, with secondary measures of craving, cocaine withdrawal, retention, and tolerability. We found no significant differences between modafinil and placebo patients on any of these measures. However, there was a significant gender difference in that male patients treated with 400 mg/day tended to be more abstinent than their placebo-treated counterparts (p = .06). Our negative findings might be explained by gender differences and/or inadequate psychosocial treatment intensity in patients with severe cocaine dependence.

Amantadine in the treatment of pathological gambling: a case report

Despite almost a decade of intense research, effective treatment strategies for Pathological Gambling (PG) remain very challenging. This paper details a case report suggesting that the treatment of PG may benefit from the use of the non-specific glutamate blocker amantadine. The drug was well-tolerated and effective, leading to a 43-64% reduction in severity of gambling symptoms (as measured with G-SAS). Our result is discussed in the context of the glutamatergic hypothesis of addiction and in light of previous observations on the potential impact of glutamatergic agents in the treatment of PG. The role of the dopaminergic system, and its interaction with the glutamatergic system, is also explored. Further studies are required to define the true benefits of amantadine for the treatment of PG.

NIDA's Clinical Trials Network: an opportunity for HIV research in community substance abuse treatment programs

BACKGROUND/OBJECTIVES

HIV continues to be a significant problem among substance users and their sexual partners in the United States. The National Drug Abuse Treatment Clinical Trials Network (CTN) offers a national platform for effectiveness trials of HIV interventions in community substance abuse treatment programs. This article presents the HIV activities of the CTN during its first 10 years.

RESULTS

While emphasizing CTN HIV protocols, this article reviews the (1) HIV context for this work; (2) the collaborative process among providers, researchers, and National Institute on Drug Abuse CTN staff, on which CTN HIV work was based; (3) results of CTN HIV protocols and HIV secondary analyses in CTN non-HIV protocols; and (4) implications for future HIV intervention effectiveness research in community substance abuse treatment programs.

CONCLUSION/SIGNIFICANCE

While the feasibility of engaging frontline providers in this research is highlighted, the limitations of small to medium effect sizes and weak adoption and sustainability in everyday practice are also discussed.

Dopamine agonists for the treatment of cocaine dependence

BACKGROUND

Cocaine dependence is a disorder for which no pharmacological treatment of proven efficacy exists, advances in the neurobiology could guide future medication development

OBJECTIVES

To investigate the efficacy and acceptability of dopamine agonists alone or in combination with any psychosocial intervention for the treatment of cocaine abuse and dependence

SEARCH METHODS

We searched the Cochrane Drugs and Alcohol Group (CDAG) Specialized Register, PubMed, EMBASE and CINAHL, PsycINFO in June 2011 and researchers for unpublished trials

SELECTION CRITERIA

Randomised and controlled clinical trials comparing dopamine agonists alone or associated with psychosocial intervention with placebo, no treatment, other pharmacological interventions

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data

MAIN RESULTS

Twenty three studies, 2066 participants, met the inclusion criteria. Comparing any dopamine agonist versus placebo, placebo performed better for severity of dependence, four studies, 232 participants, SMD 0.43 (95% CI 0.15 to 0.71), depression, five studies, 322 participants, SMD 0.42 (95% CI 0.19 to 0.65) and abstinent at follow up RR 0.57 (95% CI 0.35 to 0.93). No statistically significant different for the other outcomes considered. Comparing amantadine versus placebo, results never gain the statistical significance, but there is a trend in favour of amantadine for dropouts and depression. Results on adverse events and depression, were in favour of placebo although the difference do not reach the statistical significance. Comparing bromocriptine and Ldopa/Carbidopa versus placebo, results never reached statistical significance. Comparing amantadine versus antidepressants, antidepressants performed better for abstinence. The other two outcomes considered did not show statistically significant differences although dropouts and adverse events tended to be more common in the antidepressant group.The quality of evidence, assessed according to GRADE method, may be judged as moderate for the efficacy of any dopamine agonist versus placebo and as moderate to high for amantadine versus placebo and versus antidepressants.

AUTHORS' CONCLUSIONS

Current evidence from randomised controlled trials does not support the use of dopamine agonists for treating cocaine dependence. This absence of evidence may leave to clinicians the alternative of balancing the possible benefits against the potential adverse effects of the treatment. Even the potential benefit of combining a dopamine agonist with a more potent psychosocial intervention which was suggested by the previous Cochrane review (Soares 2003), is not supported by the results of this updated review.

Teaching condom use skills: practice is superior to observation

Men exposed to a condom skills practice exercise were hypothesized to perform better on condom skills measures than those exposed only to a demonstration or to no intervention. As part of a larger National Institute on Drug Abuse (NIDA) Clinical Trials Network HIV Prevention protocol, men in substance abuse treatment were administered male and female condom use skills measures (MCUS, FCUS) at preintervention, 2 weeks, 3 months, and 6 months postintervention. The MCUS and FCUS scores were compared for 3 intervention exposure groups (demonstration only [DO, n = 149], demonstration plus practice [D+P; n = 112], attended no sessions [NS, n = 139]) across the 4 assessment time points using a mixed effects linear regression model. There is a statistically significant intervention group-by-time effect (P < .0001) for both the MCUS and FCUS. Post hoc, pairwise linear trends across time indicated that for both the MCUS and the FCUS, the D+P group is significantly superior to the DO group and the NS group.

Gender differences in the rates and correlates of HIV risk behaviors among drug abusers

This study examined gender differences in the rates and correlates of HIV risk behaviors among 1,429 clients participating in multi-site trials throughout the United States between 2001 and 2005 as part of the National Institute on Drug Abuse-funded Clinical Trials Network. Women engaged in higher risk sexual behaviors. Greater alcohol use and psychiatric severity were associated with higher risk behaviors for women, while impaired social relations were associated with decreased risk for men. Specific risk factors were differentially predictive of HIV risk behaviors for women and men, highlighting the need for gender-specific risk-reduction interventions. Limitations of the study are discussed.

Men in methadone maintenance versus psychosocial outpatient treatment: differences in sexual risk behaviors and intervention effectiveness from a multisite HIV prevention intervention trial

The effectiveness of the Real Men Are Safe (REMAS) HIV prevention intervention was examined as a function of treatment program modality. REMAS was associated with significantly larger decreases in unprotected sexual occasions than an HIV education control condition in both treatment modalities. REMAS had superior effectiveness for reducing unprotected sexual occasions in the psychosocial outpatient compared to methadone. At the 6-month follow-up, the adjusted mean change for REMAS completers in psychosocial outpatient (M=6.4, d=0.38) was greater than for REMAS completers in methadone programs (M=2.3, d=0.25). Reasons for why REMAS appears to be especially effective in psychosocial outpatient programs are explored.

Pharmacotherapy of addictive disorders

Substance use disorders are highly prevalent in the United States and cause considerable damage to our society. They are underrecognized and undertreated despite a vast body of literature demonstrating the efficacy of treatment using both psychosocial and psychopharmacological modalities. For the last decade, research and progress into the biological basis of the addictive process has led to a rapidly growing number of pharmacological agents used to interrupt the addictive process at its various stages such as the initiation of substance abuse, the transition from abuse to dependence, and the prevention of drug reinstatement or relapse. Food and Drug Administration-approved medications exist for nicotine, alcohol, and opioid use disorders, and progress is being made to develop agents for stimulant use disorders. Regarding nicotine use disorders, nicotine replacement therapies,bupropion and varenicline, have Food and Drug Administration approval, and future options exist with endocannabinoid antagonists and immune therapy. Aversive agents, opiate antagonists, and glutamate based interventions are currently approved to treat alcohol use disorders with future promise with GABAergic, serotonergic, and endocannabinoid system agents. Opiate addiction is treated by approved agonist and antagonist mu-opioid medications with the future potential for agents that can modulate the stress systems and the iboga alkaloids. Although no pharmacotherapies are currently approved for cocaine addiction, promising lines of research include agents that affect dopaminergic, GABAergic, serotonergic,and glutamatergic systems as well as the promise for immune therapies.

Cocaine-induced neuroadaptations in glutamate transmission: potential therapeutic targets for craving and addiction

A growing body of evidence indicates that repeated exposure to cocaine leads to profound changes in glutamate transmission in limbic nuclei, particularly the nucleus accumbens. This review focuses on preclinical studies of cocaine-induced behavioral plasticity, including behavioral sensitization, self-administration, and the reinstatement of cocaine seeking. Behavioral, pharmacological, neurochemical, electrophysiological, biochemical, and molecular biological changes associated with cocaine-induced plasticity in glutamate systems are reviewed. The ultimate goal of these lines of research is to identify novel targets for the development of therapies for cocaine craving and addiction. Therefore, we also outline the progress and prospects of glutamate modulators for the treatment of cocaine addiction.

The impact of trauma-focused group therapy upon HIV sexual risk behaviors in the NIDA Clinical Trials Network "Women and trauma" multi-site study

Women in drug treatment struggle with co-occurring problems, including trauma and post-traumatic stress disorder (PTSD), which can heighten HIV risk. This study examines the impact of two group therapy interventions on reduction of unprotected sexual occasions (USO) among women with substance use disorders (SUD) and PTSD. Participants were 346 women recruited from and receiving treatment at six community-based drug treatment programs participating in NIDA's Clinical Trials Network. Participants were randomized to receive 12-sessions of either seeking safety (SS), a cognitive behavioral intervention for women with PTSD and SUD, or women's health education (WHE), an attention control psychoeducational group. Participants receiving SS who were at higher sexual risk (i.e., at least 12 USO per month) significantly reduced the number of USO over 12-month follow up compared to WHE. High risk women with co-occurring PTSD and addiction may benefit from treatment addressing coping skills and trauma to reduce HIV risk.

WITHDRAWN: Dopamine agonists for cocaine dependence

BACKGROUND

Cocaine dependence is a common and serious condition, which has become a substantial public health problem. There is a wide and well documented range of consequences associated to chronic use of cocaine, such as medical, psychological and social problems.. Therapeutic management of the cocaine addicts includes an initial period of abstinence from the drug. During this phase the subjects may experience, besides the intense craving for cocaine, symptoms such as depression, fatigue, irritability, anorexia, and sleep disturbances. It was demonstrated that the acute use of cocaine may enhance dopamine transmission and chronically it decreases dopamine concentrations in the brain. Pharmacological treatment that affects dopamine could theoretically reduce these symptoms and contribute to a more successful therapeutic approach.

OBJECTIVES

To evaluate the efficacy and acceptability of dopamine agonists for treating cocaine dependence.

SEARCH STRATEGY

Electronic searches of Cochrane Library, EMBASE, MEDLINE, PsycLIT, Biological Abstracts and LILACS; reference searching; personal communication; conference abstracts; unpublished trials from pharmaceutical industry; book chapters on treatment of cocaine dependence, was performed for the primary version of this review in 2001. Another search of the electronic databases was done in December of 2002 for this update. The specialised register of trials of the Cochrane Group on Drugs and Alcohol was searched until February 2003.

SELECTION CRITERIA

The inclusion criteria for all randomised controlled trials were that they should focus on the use of dopamine agonists on the treatment of cocaine dependence.

DATA COLLECTION AND ANALYSIS

The reviewers extracted the data independently and Relative Risks, weighted mean difference and number needed to treat were estimated. The reviewers assumed that people who died or dropped out had no improvement and tested the sensitivity of the final results to this assumption.

MAIN RESULTS

Seventeen studies were included, with 1224 participants randomised. Amantadine, bromocriptine, and pergolide were the drugs evaluated. The main outcomes evaluated were positive urine sample for cocaine metabolites, for efficacy, and retention in treatment, as an acceptability measure. There were no significant differences between interventions, and in trials where participants had primary cocaine dependence or had additional diagnosis of opioid dependence and/or were in methadone maintenance treatment.

AUTHORS' CONCLUSIONS

Current evidence does not support the clinical use of dopamine agonists in the treatment of cocaine dependence. Given the high rate of dropouts in this population, clinicians may consider adding other supportive measures aiming to keep patients in treatment.

Novel pharmacological approaches to drug abuse treatment

The field of pharmacologic addiction treatment is expanding rapidly. While there are currently several FDA-approved medications for nicotine, alcohol, and opiate dependence, research into novel pharmacological approaches for these and additional substances is legion. Each drug of abuse, while sharing a common final neural pathway of increasing dopaminergic tone, has unique and individual characteristics that are important in developing improved and varied treatments. In this chapter, we discuss such research and present the neurobiological underpinnings of these explorations. In general, addiction treatment is focused on four areas: (1) reducing withdrawal discomfort, (2) diminishing cravings, (3) blocking rewarding effects of the drug, and (4) treating comorbidities, such as depression or ADHD. We present current ideas in pharmacologic research for nicotine, alcohol, cannabis, stimulants, and opiates.

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.

Gender differences in predictors of treatment attrition with high dose naltrexone in cocaine and alcohol dependence

Recently, we reported that naltrexone at 150 mg/day significantly decreased cocaine and alcohol use for men but not women with co-occurring cocaine and alcohol dependence. The present study is an exploratory investigation of predictors that explain the different gender responses to naltrexone, with a particular focus on differential predictors of treatment attrition. No significant predictors were associated with treatment discontinuation in men. Women, however, were more likely to discontinue treatment when reporting severe pre-treatment psychiatric problems or nausea while in treatment. Further research on the impact of pre-treatment and in-treatment gender differences with naltrexone is warranted.

Bupropion hydrochloride versus placebo, in combination with cognitive behavioral therapy, for the treatment of cocaine abuse/dependence

Bupropion hydrochloride is a dopamine and norepinephrine reuptake inhibitor which may be an effective treatment for cocaine dependence due to its ability to reverse deficits in dopaminergic functioning that occur in chronic cocaine users. We performed a randomized, double-blind, placebo controlled trial comparing outpatient treatment with bupropion (N = 37) and placebo (N = 33) in combination with standard cognitive behavioral therapy. There were no statistically significant differences between bupropion and placebo in treatment outcomes, including aggregate measures of urine drug screen results (Joint Probability Index at 16 weeks: 0.43 for bupropion and 0.38 for placebo), treatment retention, cocaine craving ratings, and assessments of depressive symptoms. The failure to find an effect for bupropion relative to placebo, when combined with standard cognitive behavioral therapy, dampens enthusiasm for future development of bupropion as a cocaine pharmacotherapy.

Gender differences with high-dose naltrexone in patients with co-occurring cocaine and alcohol dependence

This is a randomized, double-blind, placebo-controlled clinical trial that evaluated the efficacy of a higher-than-typical daily dose of naltrexone (150 mg/day), taken for 12 weeks, in 164 patients (n = 116 men and n = 48 women) with co-occurring cocaine and alcohol dependence. Patients were stratified by gender and then randomly assigned to either naltrexone or placebo, and to either cognitive-behavioral therapy or a type of medical management. The two primary outcomes were cocaine use and alcohol use. Significant Gender x Medication interactions were found for cocaine use via urine drug screens (three way, with time) and self-reports (two way) for drug severity (two way) and alcohol use (two way). The type of psychosocial treatment did not affect outcomes. Thus, 150 mg/day naltrexone added to a psychosocial treatment resulted in reductions in cocaine and alcohol use and drug severity in men, compared to higher rates of cocaine and alcohol use and drug severity in women.

A double blind, placebo-controlled trial that combines disulfiram and naltrexone for treating co-occurring cocaine and alcohol dependence

BACKGROUND

This is a double blind, placebo-controlled trial that evaluated the efficacy of disulfiram, naltrexone and their combination in patients with co-occurring cocaine and alcohol dependence.

METHODS

208 patients were randomized to disulfiram (250 mg/day), naltrexone (100 mg/day), the combination, or placebo for 11 weeks. Outcomes were in-trial abstinence from cocaine and/or alcohol.

RESULTS

Few safety concerns were reported, although medication adherence was low in a number of patients for both medications, alone or in combination. In the primary analyses (GEE modeling), abstinence from cocaine as measured by cocaine-negative urines and days of self-reported abstinence from cocaine or alcohol did not differ between placebo and any of the medication groups. However, patients taking disulfiram (alone or in combination) were most likely to achieve combined abstinence from cocaine and alcohol. Secondary analyses revealed that patients taking the disulfiram-naltrexone combination were most likely to achieve 3 consecutive weeks of abstinence from cocaine and alcohol.

CONCLUSION

There was an association between disulfiram treatment and abstinence from cocaine and alcohol. More patients taking the disulfiram-naltrexone combination achieved 3 consecutive weeks of abstinence in treatment than placebo-treated patients.

Therapeutic options and challenges for substances of abuse

Addiction to substances continues to be a significant public health concern in the United States. The following review of current pharmacological treatments discusses a range of substances: nicotine, alcohol, cocaine, and opioids. The goal is to provide an overview of currently available and new pharmacological treatments for substance use disorders, while also addressing the pharmacothera-peutic challenges remaining. The significant advances in pharmacotherapy have had limited utilization, however. For example, naltrexone for alcoholism is infrequently prescribed, buprenorphine for opiates still has relatively few qualified prescribers, and stimulants have no Food and Drug Administration-approved pharmacotherapy. These pharmacotherapies are needed, with the rate of even the relatively uncommon abuse of opiates now rising sharply.

Subjective and cardiovascular effects of cocaine during treatment with amantadine and baclofen in combination

This study assessed the subjective and cardiovascular effects of relevant doses of cocaine administration during steady-state treatment of the combination of amantadine and baclofen compared to placebo. Participants included 8 healthy, male, cocaine-dependent, non-treatment-seeking individuals (age=36.6+/-5.9; 75% African American, 25% Caucasian; using cocaine for an average of 15.3+/-6.5 years). Data were collected prior to and following double-blind intravenous administration of 0 mg, 20 mg, and 40 mg of cocaine. Data were collected at baseline, following 5 days of treatment with placebo, and again following 5 days of treatment with a combination of amantadine 100 mg t.i.d. and baclofen 30 mg t.i.d. counterbalanced for order of medication and placebo in a cross-over design. Results showed no significant alterations to cardiovascular variables (heart rate, systolic and diastolic blood pressure) from treatment using combination medication or placebo in the presence of cocaine. Self-rated "desire" for cocaine was significantly lower during cocaine administrations while participants were receiving treatment with amantadine-baclofen compared to infusions while taking placebo medication, although there was no difference in the intensity of cocaine-induced euphoria, or reduction in the likelihood to use cocaine if given access. Study findings support the safety of the amantadine-baclofen combination treatment for cocaine dependence.

New developments in the pharmacotherapy of cocaine abuse

Despite huge advances in the neuroscience of substance abuse and dependence in the past 20 years, no approved pharmacological treatment exists for cocaine abuse. The available drugs for the treatment of cocaine abuse are poorly effective, hence the need for new compounds to be screened and tested for efficacy: targeting symptoms might improve the effectiveness of the treatment of cocaine abuse and dependence. On the basis of the known neurochemistry of cocaine, some target compounds have been studied: among others, BP-897, a D3 partial agonist; vanoxerine, a highly selective inhibitor of dopamine uptake; aripiprazole, a partial mixed-action agonist approved for the treatment of schizophrenia. Recently modafinil, approved for the treatment of narcolepsy, proved effective in favouring cocaine abstinence in cocaine-abusing people. Some placebo-controlled studies also reported the effectiveness of topiramate, a licensed antiepileptic drug, and of tiagabine, a gamma-aminobutyric acid (GABA) re-uptake inhibitor also approved as an anticonvulsant; both compounds increased cocaine abstinence with no serious adverse events. Promising results came from two more compounds acting on the GABA circuits, baclofen and valproic acid. Finally disulfiram, prescribed with active psychosocial therapy, was found to favour higher retention rates and longer abstinence periods from both alcohol and cocaine in polydrug-abusing patients. An alternative approach rests on the use of vaccines, to date in the experimental stage still. Psychosocial treatments are a useful companion in the pharmacotherapy of cocaine abuse, with group therapy and contingency management therapies improving motivation and social functioning, particularly in patients abusing alcohol as well.

A double-blind, placebo-controlled trial of amantadine, propranolol, and their combination for the treatment of cocaine dependence in patients with severe cocaine withdrawal symptoms

BACKGROUND

This trial evaluated the efficacy of amantadine, propranolol and their combination in cocaine dependent patients with severe cocaine withdrawal symptoms.

METHODS

Cocaine withdrawal symptom severity was measured by the cocaine selective severity assessment (CSSA). One hundred and ninety-nine patients with high scores on the CSSA participated in a 10-week double-blind trial. Patients were randomly assigned to receive amantadine (300 mg/day), propranolol (100mg/day), a combination of amantadine (300 mg/day) and propranolol (100mg/day) or matching placebo capsules. The primary outcome measure was cocaine abstinence.

RESULTS

In the intent-to-treat sample, there were no significant differences between the four medication groups in treatment retention. The odds of cocaine abstinence showed a marginally significant increase over time in the propranolol group (p=0.06) but not in the other three groups. In highly medication-adherent patients, treatment retention was significantly better in the propranolol group compared to the placebo group (p=0.01) and the odds of cocaine abstinence increased significantly over time in the propranolol group but not in the other three groups.

CONCLUSION

In the intent-to-treat sample, none of the three active treatments (propranolol, amantadine or their combination) was significantly more effective than placebo in promoting abstinence from cocaine among patients who entered treatment with more severe cocaine withdrawal symptoms. Among patients highly adherent to study medication, propranolol treatment was associated with better treatment retention and higher rates of cocaine abstinence compared to placebo.

Gamma-hydroxybutyric acid affects the acquisition and reinstatement of cocaine-induced conditioned place preference in mice

Cocaine addicts very often use different combinations of cocaine and other drugs of abuse such as gamma-hydroxybutyric acid. The objective of the present work was to evaluate the impact of gamma-hydroxybutyric acid administration on the rewarding actions of cocaine, using the conditioned place preference procedure. Cocaine-induced conditioned place preference (50 mg/kg) was studied after pairing this drug with different gamma-hydroxybutyric acid doses (6.25, 12.5, 25, 50 and 100 mg/kg) during either the acquisition or the expression phase of the procedure. After conditioned place preference had been established, and the preference was extinguished, a reinstatement was induced by a dose of cocaine half of that used to produce conditioning, or by gamma-hydroxybutyric acid alone or by both drugs together. The doses of 12.5 and 100 mg/kg of gamma-hydroxybutyric acid blocked the acquisition of cocaine-induced conditioned place preference, and no dose affected the expression of this conditioning. Reinstatement was abolished only with the dose of 25 mg/kg gamma-hydroxybutyric acid, which did not reinstate the preference by itself. This is the first study evaluating the effects of gamma-hydroxybutyric acid on the rewarding properties of cocaine using the conditioned place preference procedure. The principal conclusion of the study is that gamma-hydroxybutyric acid does not enhance the rewarding effect of cocaine, and within a narrow margin of effective doses, blocks the acquisition and reinstatement of cocaine-induced preference.

Novel pharmacotherapeutic targets for the management of drug addiction

Despite individual variation in the liability to the abuse of psychoactive substances, there is substantial commonality shared by drugs of abuse. The knowledge of these common mechanisms together with the continued elucidation of the neurobiological underpinnings of withdrawal symptoms, drug intake, craving, relapse, and co-morbid psychiatric associations are critically important for the development of new therapeutic strategies. The present review will focus on recent advances in the development of innovative pharmacotherapeutic agents, which should promote higher efficacy (abstinence, prevention of relapse, long-term recovery) and patient compliance, as well as improved safety profiles.

Synthesis and water solubility of adamantyl-OEG-fullerene hybrids

[reaction: see text] A series of new adamantyl-oligoethyleneglycol-fullerene hybrids was prepared via Bingel-Hirsch functionalization of the C60 fullerene with various adamantyl-oligoethyleneglycol malonates. As NMDA-targeted antioxidants, these compounds may have the potential to be developed as therapeutic agents for the treatment of neurological disorders.

Novel approaches to the treatment of cocaine addiction

Cocaine addiction continues to be an important public health problem with over 1.7 million users in the US alone. Although there are no approved pharmacotherapies for cocaine addiction, a number of medications have been tested with some promising results. In this review, we summarise some of the emerging targets for cocaine pharmacotherapy including dopaminergic and GABA medications, adrenoceptor antagonists, vasodilators and immunotherapies. The brain dopamine system plays a significant role in mediating the rewarding effects of cocaine. Among dopaminergic agents tested for cocaine pharmacotherapy, disulfiram has decreased cocaine use in a number of studies. Amantadine, another medication with dopaminergic effects, may also be effective in cocaine users with high withdrawal severity. GABA is the main inhibitory neurotransmitter in the brain, and accumulating evidence suggests that the GABA system modulates the dopaminergic system and cocaine effects. Two anticonvulsant medications with GABAergic effects, tiagabine and topiramate, have yielded positive findings in clinical trials. Baclofen, a GABA(B) receptor agonist, is also promising, especially in those with more severe cocaine use. Some of the physiological and behavioural effects of cocaine are mediated by activation of the adrenergic system. In cocaine users, propranolol, a beta-adrenoceptor antagonist, had promising effects in individuals with more severe cocaine withdrawal symptoms. Cerebral vasodilators are another potential target for cocaine pharmacotherapy. Cocaine users have reduced cerebral blood flow and cortical perfusion deficits. Treatment with the vasodilators amiloride or isradipine has reduced perfusion abnormalities found in cocaine users. The functional significance of these improvements needs to be further investigated. All these proposed pharmacotherapies for cocaine addiction act on neural pathways. In contrast, immunotherapies for cocaine addiction are based on the blockade of cocaine effects peripherally, and as a result, prevent or at least slow the entry of cocaine into the brain. A cocaine vaccine is another promising treatment for cocaine addiction. The efficacy of this vaccine for relapse prevention is under investigation. Many initial promising findings need to be replicated in larger, controlled clinical trials.

Pharmacogenetics and Human Molecular Genetics of Opiate and Cocaine Addictions and Their Treatments

Opiate and cocaine addictions are major social and medical problems that impose a significant burden on society. Despite the size and scope of these problems, there are few effective treatments for these addictions. Methadone maintenance is an effective and most widely used treatment for opiate addiction, allowing normalization of many physiological abnormalities caused by chronic use of short-acting opiates. There are no pharmacological treatments for cocaine addiction. Epidemiological, linkage, and association studies have demonstrated a significant contribution of genetic factors to the addictive diseases. This article reviews the molecular genetics and pharmacogenetics of opiate and cocaine addictions, focusing primarily on genes of the opioid and monoaminergic systems that have been associated with or have evidence for linkage to opiate or cocaine addiction. This evidence has been marshalled either through identification of variant alleles that lead to functional alterations of gene products, altered gene expression, or findings of linkage or association studies. Studies of polymorphisms in the mu opioid receptor gene, which encodes the receptor target of some endogenous opioids, heroin, morphine, and synthetic opioids, have contributed substantially to knowledge of genetic influences on opiate and cocaine addiction. Other genes of the endogenous opioid and monoaminergic systems, particularly genes encoding dopamine beta-hydroxylase, and the dopamine, serotonin, and norepinephrine transporters have also been implicated. Variants in genes encoding proteins involved in metabolism or biotransformation of drugs of abuse and also of treatment agents are reviewed.

A double-blind, placebo-controlled trial of modafinil for cocaine dependence

Despite years of active research, there are still no approved medications for the treatment of cocaine dependence. Modafinil is a glutamate-enhancing agent that blunts cocaine euphoria under controlled conditions, and the current study assessed whether modafinil would improve clinical outcome in cocaine-dependent patients receiving standardized psychosocial treatment. This was a randomized, double-blind, placebo-controlled trial conducted at a university outpatient center (from 2002 to 2003) on a consecutive sample of 62 (predominantly African American) cocaine-dependent patients (aged 25-63) free of significant medical and psychiatric conditions. After screening, eligible patients were randomized to a single morning dose of modafinil (400 mg), or matching placebo tablets, for 8 weeks while receiving manual-guided, twice-weekly cognitive behavioral therapy. The primary efficacy measure was cocaine abstinence based on urine benzoylecgonine levels. Secondary measures were craving, cocaine withdrawal, retention, and adverse events. Modafinil-treated patients provided significantly more BE-negative urine samples (p=0.03) over the 8-week trial when compared to placebos, and were more likely to achieve a protracted period (> or =3 weeks) of cocaine abstinence (p=0.05). There were no serious adverse events, and none of the patients failed to complete the study as a result of adverse events. This study provides preliminary evidence, which should be confirmed by a larger study, that modafinil improves clinical outcome when combined with psychosocial treatment for cocaine dependence.

Pharmacologic management of relapse prevention in addictive disorders

Substance use disorders are an important public health problem associated with significant mortality and morbidity. Effective maintenance pharmacotherapies are available for tobacco, alcohol, and opioid use disorders. For optimum treatment response, these medications should be used in conjunction with behavioral interventions. For other drugs of abuse, especially for cocaine, medication development is an active area of research. Further research is needed to develop new pharmacotherapies for substance use disorders and establish clinical guidelines on how to use these medications most effectively.

Recent advances in the pharmacotherapy of cocaine dependence

The pharmacotherapy of cocaine dependence is a rapidly developing field of research that may soon produce efficacious medications. Expanding research on reward-related brain circuitry, which is acutely activated and chronically dysregulated by cocaine, has helped reveal the neurobiological features of cocaine dependence and is guiding pharmacologic strategies that have significant potential to improve clinical outcome. Cocaine dependence is a multifaceted disorder with distinct clinical components that may respond to different pharmacologic approaches. Pharmacologic strategies for this disorder include blocking euphoria, reducing withdrawal and negative mood symptoms, ameliorating craving, and enhancing the prefrontal cortical function that seems to be impaired in cocaine-dependent patients. One medication may not be sufficient to treat these diverse elements of cocaine dependence because preliminary studies report efficacy with medications that have opposite actions on reward-related circuits. This review highlights pertinent advances in cocaine neurobiology, recent clinical trials, and controversies in the pharmacologic treatment of cocaine dependence.

Agonist-like, replacement pharmacotherapy for stimulant abuse and dependence

Stimulant abuse and dependence are disproportionately problematic due to the combination of legal and social issues added to the serious behavioural and biological features of the disorders. These problems are compounded by adverse consequences for families and society. Illegality and stigma multiply the consequences of use and difficulties in providing treatment. Specific behavioural interventions have been demonstrated as useful in treatment of substance use disorders (SUDs). Medications also have an important role in treatment. Effective agonist and antagonist pharmacotherapies as well as symptomatic treatments exist for opioid and nicotine dependence. Neither agonists nor antagonists have been approved as uniquely effective for treatment of stimulant abuse or dependence. Still, promising results are emerging for an agonist-like or 'replacement' strategy paralleling that for nicotine and opioid dependence. Supporting data have emerged from both preclinical and clinical research environments. There are scientific, clinical, social, and legal impediments to application of an agonist-like approach to stimulant abuse and dependence. Some resemble past and current concerns about opioid replacement. Others are unique to the stimulant agents, effects, and clinical features. Here, the authors consider (1) agonist and antagonist pharmacotherapy strategies; (2) preclinical research, including methodological approaches, opioid and nicotine replacement, and agonists for stimulant dependence; (3) clinical reports with stimulant medications in cocaine dependence, and the amphetamine replacement strategy for amphetamine dependence; (4) application of agonist-like/replacement strategies, including clinical requirements and risks; and (5) directions for research.

Amantadine does not modulate reinforcing, subjective, or cardiovascular effects of cocaine in humans

Data from several clinical studies have suggested that amantadine, which has dopaminergic agonist and glutamatergic antagonist effects, may be useful for the treatment of cocaine dependence. The interaction between amantadine and smoked cocaine was examined in 10 cocaine smokers (7 men, 3 women), who participated in a 26-day inpatient study. Participants were maintained on amantadine (0 and 100 mg bid) for 5 days prior to laboratory testing, using a double-blind crossover design. Under each medication condition, participants smoked a sample dose of cocaine base (0, 12, 25, and 50 mg) once, and were subsequently given five choice opportunities, 14 min apart, to self-administer that dose of cocaine or receive a merchandise voucher ($5.00). Each cocaine dose was tested twice under each medication condition, and the order of medication condition and cocaine dose varied systematically. Cocaine produced stimulant-like reinforcing, subjective, and physiological effects. Amantadine maintenance did not modify the choice to self-administer smoked cocaine. These findings, taken together with the decidedly mixed literature, suggest that amantadine (100 mg bid) will not have a role in the treatment of cocaine dependence.

Neurobiologic processes in drug reward and addiction

Neurophysiologic processes underlie the uncontrolled, compulsive behaviors defining the addicted state. These"hard-wired"changes in the brain are considered critical for the transition from casual to addictive drug use. This review of preclinical and clinical (primarily neuroimaging) studies will describe how the delineation between pleasure, reward, and addiction has evolved as our understanding of the biologic mechanisms underlying these processes has progressed. Although the mesolimbic dopaminergic efflux associated with drug reward was previously considered the biologic equivalent of pleasure, dopaminergic activation occurs in the presence of unexpected and novel stimuli (either pleasurable or aversive) and appears to determine the motivational state of wanting or expectation. The persistent release of dopamine during chronic drug use progressively recruits limbic brain regions and the prefrontal cortex, embedding drug cues into the amygdala (through glutaminergic mechanisms) and involving the amygdala, anterior cingulate, orbitofrontal cortex, and dorsolateral prefrontal cortex in the obsessive craving for drugs. The abstinent, addicted brain is subsequently primed to return to drug use when triggered by a single use of drug, contextual drug cues, craving, or stress, with each process defined by a relatively distinct brain region or neural pathway. The compulsive drive toward drug use is complemented by deficits in impulse control and decision making, which are also mediated by the orbitofrontal cortex and anterior cingulate. Within this framework, future targets for pharmacologic treatment are suggested.

Pharmacological treatments for heroin and cocaine addiction

AIMS

To provide an overview of the pharmacological options for the treatment of heroin- and cocaine-dependent patients based on known biochemical pathways to addiction and the chronic disease model as a starting point for treatment planning.

RESULTS

Recent pre-clinical and clinical studies indicate that different brain structures and different neurotransmitters are involved in different stages of the addiction process. In addition, clinical experience shows that heroin and cocaine addiction can best be conceptualised and treated as a chronic, relapsing disorder with the following treatment goals: crisis intervention, cure or recovery (detoxification, relapse prevention) and care or partial remission (stabilization and harm reduction). The various high-quality studies, systematic literature reviews and formal meta-analyses clearly demonstrate that today many proven effective interventions are available for crisis intervention, detoxification, stabilization and harm reduction for heroin-dependent patients. Interventions directed at relapse prevention are still problematic and only effective in a minority of motivated patients in stable living conditions and adequate social support. In contrast, no proven effective pharmacological interventions are available for the treatment of cocaine-dependent patients, maybe with the exception of some patient groups that seem to benefit from treatment with disulfiram or amantadine. Treatment innovations are primarily based on experimental animal studies. Newly developed cannabinoid receptor antagonists and cortisol synthesis inhibitors show great promise.

CONCLUSION

Heroin addiction is a chronic relapsing disease that is difficult to cure, but stabilization and harm reduction can greatly increase the life time expectancy and the quality of life of the patient, his direct environment and society as a whole. Currently, no proven effective pharmacological interventions are available for cocaine addiction, and treatment has to rely on existing cognitive behaviour therapies combined with contingency management strategies.

Dopamine agonists for cocaine dependence

BACKGROUND

Cocaine dependence is a common and serious condition, which has become nowadays a substantial public health problem. There is a wide and well documented range of consequences associated to chronic use of this drug, such as medical, psychological and social problems, including the spread of infectious diseases (e.g. AIDS, hepatitis and tuberculosis), crime, violence and neonatal drug exposure. Therapeutic management of the cocaine addicts includes an initial period of abstinence from the drug. During this phase the subjects may experience, besides the intense craving for cocaine, symptoms such as depression, fatigue, irritability, anorexia, and sleep disturbances. It was demonstrated that the acute use of cocaine may enhance dopamine transmission and chronically it decreases dopamine concentrations in the brain. Pharmacological treatment that affects dopamine could theoretically reduce these symptoms and contribute to a more successful therapeutic approach.

OBJECTIVES

To evaluate the efficacy and acceptability of dopamine agonists for treating cocaine dependence.

SEARCH STRATEGY

Electronic searches of Cochrane Library, EMBASE, MEDLINE, PsycLIT, Biological Abstracts and LILACS; reference searching; personal communication; conference abstracts; unpublished trials from pharmaceutical industry; book chapters on treatment of cocaine dependence, was performed for the primary version of this review in 2001. Another search of the electronic databases was done in December of 2002 for this update. The specialised register of trials of the Cochrane Group on Drugs and Alcohol was searched until February 2003.

SELECTION CRITERIA

The inclusion criteria for all randomised controlled trials were that they should focus on the use of dopamine agonists on the treatment of cocaine dependence.

DATA COLLECTION AND ANALYSIS

The reviewers extracted the data independently and Relative Risks, weighted mean difference and number needed to treat were estimated. The reviewers assumed that people who died or dropped out had no improvement and tested the sensitivity of the final results to this assumption.

MAIN RESULTS

Seventeen studies were included, with 1224 participants randomised. Amantadine, bromocriptine, and pergolide were the drugs evaluated. The main outcomes evaluated were positive urine sample for cocaine metabolites, for efficacy, and retention in treatment, as an acceptability measure. There were no significant differences between interventions, and in trials where participants had primary cocaine dependence or had additional diagnosis of opioid dependence and/or were in methadone maintenance treatment.

REVIEWER'S CONCLUSIONS

Current evidence does not support the clinical use of dopamine agonists in the treatment of cocaine dependence. Given the high rate of dropouts in this population, clinicians may consider adding other supportive measures aiming to keep patients in treatment.