Randomized clinical trial of disulfiram for cocaine dependence or abuse during buprenorphine treatment

Disulfiram for the treatment of cocaine dependence

BACKGROUND

Cocaine is a psychostimulant used by approximately 0.4% of the general population worldwide. Cocaine dependence is a chronic mental disorder characterised by the inability to control cocaine use and a host of severe medical and psychosocial complications. There is current no approved pharmacological treatment for cocaine dependence. Some researchers have proposed disulfiram, a medication approved to treat alcohol use disorder. This is an update of a Cochrane review first published in 2010.

OBJECTIVES

To evaluate the efficacy and safety of disulfiram for the treatment of cocaine dependence.

SEARCH METHODS

We updated our searches of the following databases to August 2022: the Cochrane Drugs and Alcohol Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and PsycINFO. We also searched for ongoing and unpublished studies via two trials registries. We handsearched the references of topic-related systematic reviews and included studies. The searches had no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials that evaluated disulfiram alone or associated with psychosocial interventions versus placebo, no intervention, other pharmacological interventions, or any psychosocial intervention for the treatment of cocaine dependence.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

Thirteen studies (1191 participants) met our inclusion criteria. Disulfiram versus placebo or no treatment Disulfiram compared to placebo may increase the number of people who are abstinent at the end of treatment (point abstinence; risk ratio (RR) 1.58, 95% confidence interval (CI) 1.05 to 2.36; 3 datasets, 142 participants; low-certainty evidence). However, compared to placebo or no pharmacological treatment, disulfiram may have little or no effect on frequency of cocaine use (standardised mean difference (SMD) -0.11 standard deviations (SDs), 95% CI -0.39 to 0.17; 13 datasets, 818 participants), amount of cocaine use (SMD -0.00 SDs, 95% CI -0.30 to 0.30; 7 datasets, 376 participants), continuous abstinence (RR 1.23, 95% CI 0.80 to 1.91; 6 datasets, 386 participants), and dropout for any reason (RR 1.20, 95% CI 0.92 to 1.55; 14 datasets, 841 participants). The certainty of the evidence was low for all these outcomes. We are unsure about the effects of disulfiram versus placebo on dropout due to adverse events (RR 12.97, 95% CI 0.77 to 218.37; 1 study, 67 participants) and on the occurrence of adverse events (RR 3.00, 95% CI 0.35 to 25.98), because the certainty of the evidence was very low for these outcomes. Disulfiram versus naltrexone Disulfiram compared with naltrexone may reduce the frequency of cocaine use (mean difference (MD) -1.90 days, 95% CI -3.37 to -0.43; 2 datasets, 123 participants; low-certainty evidence) and may have little or no effect on amount of cocaine use (SMD 0.12 SDs, 95% CI -0.27 to 0.51, 2 datasets, 123 participants; low-certainty evidence). We are unsure about the effect of disulfiram versus naltrexone on dropout for any reason (RR 0.86, 95% CI 0.56 to 1.32, 3 datasets, 131 participants) and dropout due to adverse events (RR 0.50, 95% CI 0.07 to 3.55; 1 dataset, 8 participants), because the certainty of the evidence was very low for these outcomes.

AUTHORS' CONCLUSIONS

Our results show that disulfiram compared to placebo may increase point abstinence. However, disulfiram compared to placebo or no pharmacological treatment may have little or no effect on frequency of cocaine use, amount of cocaine use, continued abstinence, and dropout for any reason. We are unsure if disulfiram has any adverse effects in this population. Caution is required when transferring our results to clinical practice.

Disulfiram: A Repurposed Drug in Preclinical and Clinical Development for the Treatment of Infectious Diseases

This article reviews preclinical and clinical studies on the repurposed use of disulfiram (Antabuse) as an antimicrobial agent. Preclinical research covered on the alcohol sobriety aid includes uses as an anti-MRSA agent, a carbapenamase inhibitor, antifungal drug for candidiasis, and treatment for parasitic diseases due to protozoa (e.g., giardiasis, leishmaniasis, malaria) and helminthes (e.g., schistosomiasis, trichuriasis). Past, current, and pending clinical studies on disulfiram as a post-Lyme disease syndrome (PTLDS) therapy, an HIV latency reversal agent, and intervention for COVID-19 infections are also reviewed..

Effect of copper on the antifungal activity of disulfiram (Antabuse®) in fluconazole-resistant Candida strains

Disulfiram (Antabuse®) is an alcohol use disorder medication that exhibits antifungal activity against Candida species. The purpose of this investigation was to determine if copper potentiates the antifungal effects of disulfiram based on prior observations that the combination demonstrates increased antitumor activity. Our findings revealed that copper addition conferred up to an eight-fold reduction in the minimum inhibitory concentrations (MICs) of disulfiram by broth microdilution assessment. Unexpectedly, copper was also found to nullify the fungicidal activity of disulfiram despite the significant reduction in MICs. It was therefore concluded that copper likely increased the antifungal potency of disulfiram through formation of a fungistatic chelation complex.

LAY SUMMARY

The effect of copper on the antifungal activity of disulfiram was evaluated against fluconazole-resistant Candida species. The study establishes that copper addition confers greater inhibition of disulfiram-treated Candida cultures, but the combination antagonizes the killing effects of disulfiram.

Molecular genetics of cocaine use disorders in humans

Drug addiction, one of the major health problems worldwide, is characterized by the loss of control in drug intake, craving, and withdrawal. At the individual level, drugs of abuse produce serious consequences on health and have a negative impact on the family environment and on interpersonal and work relationships. At a wider scale, they have significant socio-economic and public health consequences and they cause delinquency and citizen insecurity. Cocaine, a psychostimulant substance, is one of the most used illicit drugs, especially in America, Western Europe, and Australia. Cocaine use disorders (CUD) are complex multifactorial conditions driven by both genetic and environmental influences. Importantly, not all people who use cocaine develop CUD, and this is due, at least in part, to biological factors that are encoded in the genome of individuals. Acute and repeated use of cocaine induces epigenetic and gene expression changes responsible for the neuronal adaptations and the remodeling of brain circuits that lead to the transition from use to abuse or dependence. The purpose of this review is to delineate such factors, which should eventually help to understand the inter-individual variability in the susceptibility to cocaine addiction. Heritability estimates for CUD are high and genetic risk factors for cocaine addiction have been investigated by candidate gene association studies (CGAS) and genome-wide association studies (GWAS), reviewed here. Also, the high comorbidity that exists between CUD and several other psychiatric disorders is well known and includes phenotypes like schizophrenia, aggression, antisocial or risk-taking behaviors. Such comorbidities are associated with a worse lifetime trajectory, and here we report shared genetic factors that may contribute to them. Gene expression changes and epigenetic modifications induced by cocaine use and chronic abuse in humans are addressed by reviewing transcriptomic studies performed on neuronal cells and on postmortem brains. We report some genes which expression is altered by cocaine that also bear genetic risk variants for the disorder. Finally, we have a glance to the pharmacogenetics of CUD treatments, still in early stages. A better understanding of the genetic underpinnings of CUD will foster the search of effective treatments and help to move forward to personalized medicine.

Pharmacotherapy treatment of stimulant use disorder

Stimulant use disorder (SUD) is a public health problem in the United States that is associated with increased morbidity and mortality. Psychosocial interventions, such as cognitive behavioral therapy and contingency management, are the main treatment modality for SUDs and no pharmacotherapy is currently FDA approved for this indication. Although some medications show promising data for the treatment of SUD, the evidence remains inconsistent, and the clinical application is limited due to the heterogenicity of the population and the lack of studies in patients with various comorbidities. Selection of pharmacotherapy treatment for methamphetamine intoxication, persistent methamphetamine-associated psychosis with methamphetamine use disorder, and cocaine use disorder in patients with co-occurring OUD are discussed in 3 patient cases.

Advantages and disadvantages of disulfiram coadministered with popular addictive substances

Disulfiram (DSF) is a well-known anti-alcohol agent that inhibits aldehyde dehydrogenase and results in extreme 'hangover' symptoms when consumed with alcohol. This drug, however, has been suggested as useful in other forms of drug addiction due to its beneficial potential in both drug abuse reduction and withdrawal. However, among other drugs used in alcohol dependence, it carries the greatest risk of pharmacological interactions. Concomitant use of DSF and central nervous system stimulants usually leads to harmful, undesirable effects. To date, there is still limited data regarding the detailed safety profile of DSF as a concomitant drug. In this review article, we outline the current state of knowledge about DSF, its broad pharmacological action, as well as therapeutic effects, with a particular emphasis on the molecular understanding of its potential pharmacodynamic interactions with common addictive substances (e.g., alcohol, cocaine, cannabinoids, opioids) supported by relevant examples.

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

BACKGROUND

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

ARGUMENT

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

CONCLUSION

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

A systematic review and meta-analysis of medications for stimulant use disorders in patients with co-occurring opioid use disorders

BACKGROUND

Stimulant (cocaine and/or methamphetamine) use has increased among people with opioid use disorder. We conducted a systematic review of medications for stimulant use disorders in this population.

METHODS

We searched for randomized controlled trials in multiple databases through April 2019, and dual-screened studies using pre-specified inclusion criteria. Primary outcomes were abstinence defined as stimulant-negative urine screens for ≥3 consecutive weeks; overall use as the proportion of stimulant-negative urine specimens; and retention as the proportion of participants who completed treatment. We rated strength of evidence using established criteria and conducted meta-analyses of comparable interventions and outcomes.

RESULTS

Thirty-four trials of 22 medications focused on cocaine use disorder in patients with opioid use disorder. Most studies enrolled participants stabilized on opioid maintenence therapy, generally methadone. None of the six studies that assessed abstinence found significant differences between groups. We found moderate-strength evidence that antidepressants (desipramine, bupropion, and fluoxetine) worsened retention. There was moderate-strength evidence that disulfiram worsened treatment retention (N = 605, RR 0.86, 95 % CI 0.77 to 0.95). We found low-strength evidence that psychostimulants (mazindol and dexamphetamine) may reduce cocaine use, though the difference was not statistically significant (standard mean difference 0.35 [95 % CI -0.05 to 0.74]). There was only 1 trial for methamphetamine use disorder, which showed insufficient-strength evidence for naltrexone.

CONCLUSIONS

Co-occurring stimulant/opioid use disorder is an important problem for targeting future research. Medication trials for methamphetamine use disorder are lacking in this population. Most of the medications studied for cocaine use were ineffective, although psychostimulants warrant further study.

Clinical effects beyond cocaine use of sustained-release dexamphetamine for the treatment of cocaine dependent patients with comorbid opioid dependence: secondary analysis of a double-blind, placebo-controlled randomized trial

BACKGROUND AND AIMS

Sustained-release (SR) formulations of dexamphetamine and mixed amphetamine salts have shown positive effects in the treatment of patients with a cocaine use disorder. We previously demonstrated the efficacy of SR-dexamphetamine for patients with cocaine dependence in terms of cocaine use reductions. In this secondary analysis, we assessed whether SR-dexamphetamine treatment also improves the health status of these patients.

DESIGN

Multi-centre randomized, double-blind placebo-controlled trial.

SETTING

Four supervised heroin-assisted treatment (HAT) out-patient clinics in the Netherlands. In HAT, methadone treatment-refractory opioid-dependent patients can self-administer individually titrated doses of pharmaceutical grade diacetylmorphine, coprescribed with oral methadone.

PARTICIPANTS

Seventy-three cocaine-dependent patients (90% males; average age = 48.7 years), participating in HAT for their treatment-refractory comorbid opioid dependence.

INTERVENTIONS

Twelve weeks pharmacotherapy with once-daily, supervised intake of two tablets of SR-dexamphetamine (2 × 30 mg/day) or two identical placebo tablets.

MEASUREMENTS

Assessment every 4 weeks: cocaine use (time-line follow-back), physical health (Maudsley Addiction Profile-Health Symptoms Scale), mental health (Brief Symptom Inventory) and illegal activities (Addiction Severity Index). Primary outcome was 'overall health', a dichotomous, multi-domain response index based on physical health, mental health and social functioning.

FINDINGS

Compared with placebo, SR-dexamphetamine resulted in larger increases in the number of cocaine abstinent days (P = 0.004) and the proportion of overall health treatment responders (P = 0.045) from the 4 weeks preceding baseline to the final 4 weeks of treatment. While the number of cocaine abstinent days was not associated with overall health in the total study sample, it was positively associated with overall health among patients in poor overall health at the start of SR-dexamphetamine treatment (n = 50), i.e. patients with the potential to improve on this multi-domain response index (odds ratio = 1.076; 95% confidence interval = 1.025-1.130).

CONCLUSIONS

SR-dexamphetamine reduces cocaine use and may improve clinically relevant health-related outcomes in patients with cocaine dependence who are participating in heroin-assisted treatment for their comorbid heroin dependence.

Pharmacotherapy for Cocaine Use Disorder-a Systematic Review and Meta-analysis

BACKGROUND

Currently, there are no accepted FDA-approved pharmacotherapies for cocaine use disorder, though numerous medications have been tested in clinical trials. We conducted a systematic review and meta-analysis to better understand the effectiveness of pharmacotherapy for cocaine use disorder.

METHODS

We searched multiple data sources (MEDLINE, PsycINFO, and Cochrane Library) through November 2017 for systematic reviews and randomized controlled trials (RCTs) of pharmacological interventions in adults with cocaine use disorder. When possible, we combined the findings of trials with comparable interventions and outcome measures in random-effects meta-analyses. We assessed the risk of bias of individual trials and the strength of evidence for each outcome using standardized criteria. Outcomes included continuous abstinence (3+ consecutive weeks); cocaine use; harms; and study retention. For relapse prevention studies (participants abstinent at baseline), we examined lapse (first cocaine positive or missing UDS) and relapse (two consecutive cocaine positive or missed UDS').

RESULTS

Sixty-six different drugs or drug combinations were studied in seven systematic reviews and 48 RCTs that met inclusion criteria. Antidepressants were the most widely studied drug class (38 RCTs) but appear to have no effect on cocaine use or treatment retention. Increased abstinence was found with bupropion (2 RCTs: RR 1.63, 95% CI 1.02 to 2.59), topiramate (2 RCTs: RR 2.56, 95% CI 1.39 to 4.73), and psychostimulants (14 RCTs: RR 1.36, 95% CI 1.05 to 1.77), though the strength of evidence for these findings was low. We found moderate strength of evidence that antipsychotics improved treatment retention (8 RCTs: RR 1.33, 95% CI 1.03 to 1.75).

DISCUSSION

Most of the pharmacotherapies studied were not effective for treating cocaine use disorder. Bupropion, psychostimulants, and topiramate may improve abstinence, and antipsychotics may improve retention. Contingency management and behavioral interventions along with pharmacotherapy should continue to be explored.

SR REGISTRATION

Prospero CRD42018085667.

Medications to treat cocaine use disorders: current options

PURPOSE OF REVIEW

Cocaine is a highly addictive substance with serious medical and mental health consequences. Despite these concerns, there are no Food and Drug Administration-approved medications for the treatment of cocaine use disorder (CUD). Although many medication-assisted treatments (MATs) have been investigated, no clear guidelines exist for clinicians treating patients with CUDs.

RECENT FINDINGS

There are a limited number of recent data examining MATs for CUD. Multiple high-quality reviews of existing literature have been performed with psychostimulants, modafinil, bupropion, topiramate and disulfiram showing the most promise. Evidence is limited by heterogeneity of studies, small sample sizes and inconsistent results.

SUMMARY

The current literature does not strongly support any individual MAT for CUD. Psychosocial interventions, namely contingency management, have the most evidence for treatment of CUD, but it is worth seriously considering MAT for patients who do not respond well to psychosocial interventions alone given limitations in access to care, relatively low risks associated with MAT and significant morbidity associated with CUD. Further research into MAT for CUD is necessary, as the combination of MAT and psychosocial interventions may be better than either alone.

Pharmacogenetic role of dopamine transporter (SLC6A3) variation on response to disulfiram treatment for cocaine addiction

BACKGROUND AND OBJECTIVES

Disulfiram has been beneficial in treating cocaine addiction in several studies. Patients with two SLC6A3 (DAT1) rs28363170 10-repeat alleles who have with genetically high dopamine transporter (DAT) levels may benefit from increased dopamine levels resulting from disulfiram treatment.

METHODS

After stabilization for 2 weeks on methadone, 70 cocaine and opioid codependent patients were randomized into disulfiram and placebo groups for 12 weeks of treatment. We genotyped the SLC6A3 (DAT1) 40 bp 3'-untranslated region variable number tandem repeat variant and evaluated its role in moderating disulfiram efficacy for cocaine dependence.

RESULTS

Among the 10,10-repeat genotype group, cocaine-positive urines dropped from 78% to 48% and from 80% to 75% among the 9-repeat carrier group in the disulfiram group (P = 0.0001, with an effect size of 0.09). No difference was observed in cocaine-positive urines in the placebo group between the 10,10-repeat genotype and the 9-allele carrier patients.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

We found that patients with genetically higher DAT levels had better treatment outcomes with disulfiram pharmacotherapy of cocaine dependence than those with lower DAT levels. (Am J Addict 2019;28:311-317).

Pharmacogenetics of Dopamine β-Hydroxylase in cocaine dependence therapy with doxazosin

The α₁ -adrenergic antagonist, doxazosin, has improved cocaine use disorder (CUD) presumably by blocking norepinephrine (NE) stimulation and reward from cocaine-induced NE increases. If the NE levels for release were lower, then doxazosin might more readily block this NE stimulation and be more effective. The NE available for release can be lower through a genetic polymorphism in dopamine β-hydroxylase (DBH) (C-1021T, rs1611115), which reduces DβH's conversion of dopamine to NE. We hypothesize that doxazosin would be more effective in CUD patients who have these genetically lower DβH levels. This 12-week, double-blind, randomized, placebo-controlled trial included 76 CUD patients: 49 with higher DβH levels from the DBH CC genotype and 27 with lower DβH levels from T-allele carriers (CT or TT). Patients were randomized to doxazosin (8 mg/day, N = 47) or placebo (N = 29) and followed with thrice weekly urine toxicology and once weekly cognitive behavioral psychotherapy. Cocaine use was reduced at a higher rate among patients in the doxazosin than in the placebo arm. We found significantly lower cocaine use rates among patients carrying the T-allele (CT/TT) than the CC genotype. The percentage of cocaine positive urines was reduced by 41 percent from baseline in the CT/TT group with low DβH and NE levels, as compared with no net reduction in the CC genotype group with normal DβH and NE levels. The DBH polymorphism appears play an important role in CUD patients' response to doxazosin treatment, supporting a pharmacogenetic association and potential application for personalized medicine.

Treatment-refractory substance use disorder: Focus on alcohol, opioids, and cocaine

Substance use disorders are common, but only a small minority of patients receive adequate treatment. Although psychosocial therapies are effective, relapse is common. This review focusses on novel pharmacological and other treatments for patients with alcohol, opioid, or cocaine use disorders who do not respond to conventional treatments. Disulfiram, acamprosate, and the opioid antagonist naltrexone have been approved for the treatment of alcoholism. A novel, "as needed" approach is the use of the mu-opioid antagonist and partial kappa agonist nalmefene to reduce alcohol consumption. Other novel pharmacological approaches include the GABA-B receptor agonist baclofen, anticonvulsants such as topiramate and gabapentin, the partial nicotine receptor agonist varenicline, and other drugs. For opioid dependence, opioid agonist therapy with methadone or buprenorphine is the first-line treatment option. Other options include oral or depot naltrexone, morphine sulfate, depot or implant formulations, and heroin (diacetylmorphine) in treatment-refractory patients. To date, no pharmacological treatment has been approved for cocaine addiction; however, 3 potential pharmacological treatments are being studied, disulfiram, methylphenidate, and modafinil. Pharmacogenetic approaches may help to optimize treatment response in otherwise treatment-refractory patients and to identify which patients are more likely to respond to treatment, and neuromodulation techniques such as repeated transcranial magnetic stimulation and deep brain stimulation also may play a role in the treatment of substance use disorders. Although no magic bullet is in sight for treatment-refractory patients, some novel medications and brain stimulation techniques have the potential to enrich treatment options at least for some patients.

Psychotic Symptoms Associated with the use of Dopaminergic Drugs, in Patients with Cocaine Dependence or Abuse

BACKGROUND

In the field of dual diagnosis, physicians are frequently presented with pharmacological questions. Questions about the risk of developing psychotic symptoms in cocaine users who need treatment with dopaminergic drugs could lead to an undertreatment.

OBJECTIVE

Review the presence of psychotic symptoms in patients with cocaine abuse/dependence, in treatment with dopaminergic drugs.

METHODS

Systematic PubMed searches were conducted including December 2014, using the keywords: "cocaine", dopaminergic drug ("disulfuram-methylphenidate-bupropion-bromocriptine-sibutramineapomorphine- caffeine") and ("psychosis-psychotic symptoms-delusional-paranoia"). Articles in English, Spanish, Portuguese, French, and Italian were included. Articles in which there was no history of cocaine abuse/dependence, absence of psychotic symptoms, systematic reviews, and animal studies, were excluded.

RESULTS

313 papers were reviewed. 7 articles fulfilled the inclusion-exclusion criteria. There is a clinical trial including 8 cocaine-dependent patients using disulfiram in which 3 of them presented psychotic symptoms and 6 case-reports: disulfuram (1), methylphenidate (1), disulfiram with methylphenidate (2), and bupropion (2), reporting psychotic symptoms, especially delusions of reference and persecutory ideation.

CONCLUSION

Few cases have been described, which suggests that the appearance of these symptoms is infrequent. The synergy of dopaminergic effects or the dopaminergic sensitization in chronic consumption are the explanatory theories proposed by the authors. In these cases, a relationship was found between taking these drugs and the appearance of psychotic symptoms. Given the low number of studies found, further research is required. The risk of psychotic symptoms seems to be acceptable if we compare it with the benefits for the patients but a closer monitoring seems to be advisable.

Novel interventions to prevent HIV and HCV among persons who inject drugs

Persons who inject drugs (PWID) are at high risk for infection with and poor outcomes from HIV and hepatitis C virus (HCV). Well-established interventions for HIV/HCV prevention among PWID include syringe access, opioid agonist maintenance treatment, and supervised injection facilities, yet these interventions remain unavailable or inadequately resourced in much of the world. We review recent literature on biomedical and behavioral interventions to reduce the burden of HIV/HCV among PWID, with an emphasis on randomized controlled trials and quasi-experimental studies. Since 2013, there have been significant advancements in utilizing antiviral therapy and behavioral interventions for prevention among PWID, including approaches that address the unique needs of couples and sex workers. In addition, there have been significant developments in pharmacotherapies for substance use and the implementation of naloxone for opioid overdose prevention. Notwithstanding multiple ongoing structural challenges in delivering HIV/HCV prevention interventions to PWID, these emerging and rigorously evaluated interventions expand possibilities for prevention among PWID.

Decision-making processes as predictors of relapse and subsequent use in stimulant-dependent patients

BACKGROUND

Decision-making processes have been posited to affect treatment outcome in addicted patients.

OBJECTIVE

The present multi-site study assessed whether two measures of decision-making predicted relapse and subsequent use in stimulant-dependent patients.

METHODS

A total of 160 methamphetamine- or cocaine-dependent patients participating in a multi-site clinical trial evaluating a modified 12-step facilitation intervention for stimulant-dependent patients (STAGE-12) were assessed. Decision-making processes of risk and delay (Iowa Gambling Task [IGT]) and response reversal (Wisconsin Card Sorting Task [WCST]) were obtained shortly after treatment admission followed by assessment of stimulant use over the next six months. The relationships of the IGT and WCST (Perseverative Errors) with relapse (yes/no) and days of stimulant use during the 6-month period following post-randomization were evaluated.

RESULTS

Performance on the IGT and WCST did not significantly predict relapse status or time to relapse. Unexpectedly, worse performance on the IGT was associated with a fewer number of stimulant use days (p = 0.001). In contrast, worse performance on the WCST (more perseverative errors) was associated with a greater number of stimulant use days (p = 0.0003). The predictive effects of perseverative errors on subsequent use were confined to methamphetamine-dependent and Minority participants.

CONCLUSIONS

Decision-making processes, as measured in the current study, do not uniformly predict relapse or subsequent use. A decrease in the salience attribution of non-drug reinforcers may explain the positive relationship between IGT performance and post-relapse use. More comprehensive and global measures of impulsiveness may better assess relapse risk and use.

Pilot study of the effects of lisdexamfetamine on cocaine use: A randomized, double-blind, placebo-controlled trial

BACKGROUND

Amphetamine analogs have been demonstrated to have some efficacy in reducing use in cocaine dependent individuals. However, these agents also have potential for abuse. Lisdexamfetamine (LDX), a lysine+dextroamphetamine formulation, has been approved for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD) and as a prodrug, has less abuse potential.

OBJECTIVE

This pilot study sought to evaluate the safety, tolerability, and efficacy of LDX as a candidate treatment for cocaine dependence.

METHODS

A randomized, double-blind, placebo-controlled parallel group study served to evaluate LDX in 43 cocaine-dependent individuals: (1) placebo (PBO; 0mg, n=21), (2) LDX (70mg, n=22). Participants received medication for 14 weeks. Cocaine use was determined based on urine analysis for benzoylecgonine (BE; a cocaine metabolite).

RESULTS

Retention rates were higher though not significantly different in the PBO (71.4%) than the LDX condition (57.1%). Compared to those in the PBO condition, those receiving LDX were more likely to report experiencing (ps<0.05) diarrhea (45.5% vs. 14.3%), headaches (45.5% vs. 9.5%), and anxiety (31.8% vs. 4.8%). No differences in medication conditions were observed for blood pressure, heart rate, or body weight. In the randomized sample, no differences in cocaine use were seen. Those receiving LDX reported significantly less craving for cocaine than participants receiving PBO.

CONCLUSIONS

LDX did not significantly reduce cocaine use compared to PBO in the randomized sample.

Evaluation of the dopamine β-hydroxylase (DβH) inhibitor nepicastat in participants who meet criteria for cocaine use disorder

In the present study, we tested the hypothesis that the potent and selective dopamine-β-hydroxylase (DβH) inhibitor nepicastat would have minimal effects on cardiovascular and pharmacokinetic parameters associated with cocaine administration and would reduce the positive subjective effects produced by cocaine. We conducted a double-blind, placebo-controlled, inpatient study of oral nepicastat (0, 80 and 160mg) concurrent with intravenous (IV) cocaine (0, 10, 20 and 40mg) in non-treatment seeking participants who metcriteria for cocaine use disorder. Safety analyses revealed that nepicastat was well-tolerated and there were no differences in adverse events observed after nepicastat plus cocaine vs. cocaine alone. In addition, the pharmacokinetic properties of cocaine administration were not altered by nepicastat treatment. Cocaine-induced cardiovascular and subjective effects were evaluated for completers in the cohort randomized to nepicastat (n=13) using a within-subjects statistical analysis strategy. Specifically, the cardiovascular and subjective effects of cocaine were assessed in the presence of placebo (0mg), 80mg of nepicastat or 160mg of nepicastat on study Days 4, 8 and 12, respectively. Analyses revealed a main effect of nepicastat to reduce several cocaine-induced positive subjective effects. Taken together, these data indicate that nepicastat is safe when co-administered with cocaine and may suppress its positive subjective effects, and may be viable as a pharmacotherapy for treatment of cocaine use disorder.

Alcohol use disorders in opioid maintenance therapy: prevalence, clinical correlates and treatment

Maintenance therapy with methadone or buprenorphine is an established and first-line treatment for opioid dependence. Clinical studies indicate that about a third of patients in opioid maintenance therapy show increased alcohol consumption and alcohol use disorders. Comorbid alcohol use disorders have been identified as a risk factor for clinical outcome and can cause poor physical and mental health, including liver disorders, noncompliance, social deterioration and increased mortality risk. The effects of opioid maintenance therapy on alcohol consumption are controversial and no clear pattern has emerged. Most studies have not found a change in alcohol use after initiation of maintenance therapy. Methadone and buprenorphine appear to carry little risk of liver toxicity, but further research on this topic is required. Recent data indicate that brief intervention strategies may help reduce alcohol intake, but the existing evidence is still limited. This review discusses further clinical implications of alcohol use disorders in opioid dependence.

Emerging drugs for the treatment of cocaine use disorder: a review of neurobiological targets and pharmacotherapy

INTRODUCTION

Cocaine use is a global public health concern of significant magnitude, negatively impacting both the individual as well as larger society. Despite numerous trials, the discovery of an effective medication for treatment of cocaine use disorder remains elusive.

AREAS COVERED

This article reviews the emerging pharmacotherapies for treatment of cocaine use disorder, focusing on those medications that are currently in Phase II or III human clinical trials. Articles reviewed were obtained through searches of PubMed, Ovid MEDLINE, Clinicaltrials.gov and the Pharmaprojects database.

EXPERT OPINION

Research into cocaine pharmacotherapy must continue to show innovation. Given that medications targeting single neurotransmitter systems have demonstrated little efficacy in treatment of cocaine use disorder, the recent focus on pharmacotherapeutic agents with multiple neurobiochemical targets represents an exciting shift in trial design and approach. Additionally, consideration of pharmacogenetics may be helpful in identification of subpopulations of cocaine-dependent individuals who may preferentially respond to medications.