Naltrexone in alcohol dependence: a randomised controlled trial of effectiveness in a standard clinical setting

Patient perspectives on emergency department initiation of medication for alcohol use disorder

OBJECTIVE

Alcohol use disorder (AUD) is a leading cause of preventable death and is a frequent diagnosis in the emergency department (ED). Treatment in the ED, however, typically focuses on managing the sequelae of AUD, such as acute withdrawal, rather than addressing the underlying addiction. For many patients, these ED encounters are a missed opportunity to connect with medication for AUD. In 2020, our ED created a pathway to offer patients with AUD treatment with naltrexone (NTX) during their ED visit. The aim of this study was to identify what barriers and facilitators patients perceive to NTX initiation in the ED.

METHODS

Adopting the theoretical framework of the behavior change wheel (BCW), we conducted qualitative interviews with patients to elicit their perspectives on ED initiation of NTX. Interviews were coded and analyzed using both inductive and deductive approaches. Themes were categorized according to patients' capabilities, opportunities, and motivations. Barriers were then mapped through the BCW to design interventions that will improve our treatment pathway.

RESULTS

Twenty-eight patients with AUD were interviewed. Facilitators of accepting NTX included having recently experienced sequelae of AUD, rapid management of withdrawal symptoms by the ED provider, having a choice between intramuscular and oral formulations of the medication, and experiencing positive interactions in the ED that destigmatized the patient's AUD. Barriers to accepting treatment included lack of provider knowledge about NTX, dependence on alcohol as self-treatment for psychiatric trauma and physical pain, perceived discriminatory treatment and stigma about AUD, aversion to potential side effects, and lack of access to continued treatment.

CONCLUSIONS

Initiation of treatment of AUD with NTX in the ED is acceptable to patients and can be facilitated by knowledgeable ED providers who create a destigmatizing environment, effectively manage withdrawal symptoms, and connect patients to providers who will continue treatment.

Patterns of publicly funded naltrexone use among patients diagnosed with alcohol use disorder in Ontario

AIMS

Naltrexone is recommended first-line to manage alcohol use disorder (AUD). With previous studies indicating poor retention on naltrexone, we determined duration of naltrexone use and assessed the association between prescription setting and time to discontinuation in Ontario.

METHODS

We conducted a retrospective population-based cohort study among Ontario public drug beneficiaries diagnosed with AUD who initiated publicly funded naltrexone from June 2018 to September 2019. The primary outcome was time to naltrexone discontinuation, with a secondary analysis assessing receipt of at least one prescription refill. We used Cox proportional hazards models and logistic regression to test the association between prescription setting and each medication persistence outcome.

RESULTS

Among 2531 new naltrexone patients with AUD, the median duration of naltrexone use was 31 days and 394 (15.6%) continued naltrexone for 6 months or longer. There was no association between setting of initiation and duration of naltrexone use; however, those initiating naltrexone following an acute inpatient hospital stay were more likely to fill a second prescription (aOR 1.43, 95% CI 0.96-2.14), while those initiating after an ED visit were less likely to be dispensed a second prescription (aOR = 0.69, 95% CI 0.52-0.90) compared to those starting in a physician's office.

CONCLUSION

Persistence on naltrexone to treat an AUD is low, regardless of the setting of initiation. Further research is needed to elucidate the barriers encountered by patients with AUD that lead to poor treatment persistence in order to develop interventions that facilitate patient-centered access to evidence-based treatment for AUD in the province.

Provider perspectives on emergency department initiation of medication assisted treatment for alcohol use disorder

Background

Alcohol use disorder (AUD) is ubiquitous and its sequelae contribute to high levels of healthcare utilization, yet AUD remains undertreated. The ED encounter represents a missed opportunity to initiate medication assisted treatment (MAT) for patients with AUD. The aims of this study are to identify barriers and facilitators to the treatment of AUD in the ED, and to design interventions to address identified barriers.

Methods

Using an implementation science approach based on the Behavior Change Wheel framework, we conducted qualitative interviews with staff to interrogate their perspectives on ED initiation of AUD treatment. Subjects included physicians, nurses, nurse practitioners, clinical social workers, and pharmacists. Interviews were thematically coded using both inductive and deductive approaches and constant comparative analysis. Themes were further categorized as relating to providers’ capabilities, opportunities, or motivations. Barriers were then mapped to corresponding intervention functions.

Results

Facilitators at our institution included time allotted for continuing education, the availability of clinical social workers, and favorable opinions of MAT based on previous experiences implementing buprenorphine for opioid use disorder. Capability barriers included limited familiarity with naltrexone and difficulty determining which patients are candidates for therapy. Opportunity barriers included the limited supply of naltrexone and a lack of clarity as to who should introduce naltrexone and assess readiness for change. Motivation barriers included a sense of futility in treating patients with AUD and stigmas associated with alcohol use. Evidence-based interventions included multi-modal provider education, a standardized treatment algorithm and order set, selection of clinical champions, and clarification of roles among providers on the team.

Conclusions

A large evidence-practice gap exists for the treatment of AUD with Naltrexone, and the ED visit is a missed opportunity for intervention. ED providers are optimistic about implementing AUD treatment in the ED but described many barriers, especially related to knowledge, clarification of roles, and stigma associated with AUD. Applying a formal implementation science approach guided by the Behavior Change Wheel allowed us to transform qualitative interview data into evidence-based interventions for the implementation of an ED-based program for the treatment of AUD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-07862-1.

Brain Correlates of the Alcohol Use Disorder Pharmacotherapy Response: A Systematic Review of Neuroimaging Studies

Background: Although Alcohol Use Disorder (AUD) is highly prevalent worldwide, treating this condition remains challenging. Further, potential treatments for AUD do not fully address alcohol-induced neuroadaptive changes. Understanding the effects of pharmacotherapies for AUD on the human brain may lead to tailored, more effective treatments, and improved individual clinical outcomes. Objectives: We systematically reviewed the literature for studies investigating pharmacotherapies for AUD that included neuroimaging-based treatment outcomes. We searched the PubMed, Scielo, and PsycINFO databases up to January 2021. Study eligibility criteria, participants, and interventions: Eligible studies included those investigating pharmacotherapies for AUD and employing functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and/or proton magnetic resonance spectroscopy (H-MRS). Study appraisal and synthesis methods: Two independent reviewers screened studies’ titles and abstracts for inclusion. Data extraction forms were shared among all the authors to standardize data collection. We gathered information on the following variables: sample size; mean age; sociodemographic and clinical characteristics; alcohol use status; study design and methodology; main neuroimaging findings and brain-regions of interest (i.e., brain areas activated by alcohol use and possible pharmacological interactions); and limitations of each study. Results: Out of 177 studies selected, 20 studies provided relevant data for the research topic. Findings indicate that: (1) Acamprosate and gabapentin may selectively modulate limbic regions and the anterior cingulate cortex; (2) Naltrexone and disulfiram effects may involve prefrontal, premotor, and cerebellar regions; (3) Pharmacotherapies acting on glutamate and GABA neurotransmission involve primarily areas underpinning reward and negative affective states, and; (4) Pharmacotherapies acting on opioid and dopamine systems may affect areas responsible for the cognitive and motor factors of AUD. Limitations: Most of the studies were focused on naltrexone. A small number of studies investigated the action of disulfiram and gabapentin, and no neuroimaging studies investigated topiramate. In addition, the time between medication and neuroimaging scans varied widely across studies. Conclusions: We identified key-brain regions modulated by treatments available for AUD. Some of the regions modulated by naltrexone are not specific to the brain reward system, such as the parahippocampal gyrus (temporal lobe), parietal and occipital lobes. Other treatments also modulate not specific regions of the reward system, but play a role in the addictive behaviors, including the insula and dorsolateral prefrontal cortex. The role of these brain regions in mediating the AUD pharmacotherapy response warrants investigation in future research studies.

Pharmacogenetics of Addiction Therapy

Drug addiction is a serious relapsing disease that has high costs to society and to the individual addicts. Treatment of these addictions is still in its nascency, with only a few examples of successful therapies. Therapeutic response depends upon genetic, biological, social, and environmental components. A role for genetic makeup in the response to treatment has been shown for several addiction pharmacotherapies with response to treatment based on individual genetic makeup. In this chapter, we will discuss the role of genetics in pharmacotherapies, specifically for cocaine, alcohol, and opioid dependences. The continued elucidation of the role of genetics should aid in the development of new treatments and increase the efficacy of existing treatments.

Efficacy of pharmacotherapeutics for patients comorbid with alcohol use disorders and depressive symptoms-A bayesian network meta-analysis

Background

We aimed to compare and rank the efficacy of different pharmacotherapeutics for patients comorbid with alcohol use disorders and depressive symptoms.

Method

Bayesian network meta‐analysis was performed for three different outcome parameters: alcohol use disorders (AUD) remission rate, percent abstinent days, and scores of depression scales. The surface under the cumulative ranking curves (SUCRA) was used for ranking the efficacy of interventions. Sensitivity analysis and direct pairwise analysis were conducted to validate the main results.

Results

A total of 68 RCTs consisting of 5890 patients were included. Disulfiram could significantly increase the AUD remission rates (OR 5.02, 1.97‐12.95) and the percent abstinent days (MD 17.08, 3.48‐30.93). Disulfiram was associated with the best efficacy in achieving remission (SUCRA 95.1%) and increasing abstinent days (SUCRA 87.6%). Noradrenaline reuptake inhibitor was significantly more efficacious than controls (SMD −2.44, −3.53 to −1.36) and have the first rank (SUCRA 99.0%) in reducing the scores of depression scales. Antiepileptics have relatively higher ranks in efficacy for both AUD and depressive symptoms.

Conclusions

Disulfiram was associated with the best efficacy in achieving abstinence for comorbidity patients. Noradrenaline reuptake inhibitor was demonstrated to be associated with the best efficacy in reducing scores of depression scales. Antiepileptics might be beneficial to both alcohol‐related and depressive symptoms.

Vibration of effects from diverse inclusion/exclusion criteria and analytical choices: 9216 different ways to perform an indirect comparison meta-analysis

BACKGROUND

Different methodological choices such as inclusion/exclusion criteria and analytical models can yield different results and inferences when meta-analyses are performed. We explored the range of such differences, using several methodological choices for indirect comparison meta-analyses to compare nalmefene and naltrexone in the reduction of alcohol consumption as a case study.

METHODS

All double-blind randomized controlled trials (RCTs) comparing nalmefene to naltrexone or one of these compounds to a placebo in the treatment of alcohol dependence or alcohol use disorders were considered. Two reviewers searched for published and unpublished studies in MEDLINE (August 2017), the Cochrane Library, Embase, and ClinicalTrials.gov and contacted pharmaceutical companies, the European Medicines Agency, and the Food and Drug Administration. The indirect comparison meta-analyses were performed according to different inclusion/exclusion criteria (based on medical condition, abstinence of patients before inclusion, gender, somatic and psychiatric comorbidity, psychological support, treatment administered and dose, treatment duration, outcome reported, publication status, and risk of bias) and different analytical models (fixed and random effects). The primary outcome was the vibration of effects (VoE), i.e. the range of different results of the indirect comparison between nalmefene and naltrexone. The presence of a "Janus effect" was investigated, i.e. whether the 1st and 99th percentiles in the distribution of effect sizes were in opposite directions.

RESULTS

Nine nalmefene and 51 naltrexone RCTs were included. No study provided a direct comparison between the drugs. We performed 9216 meta-analyses for the indirect comparison with a median of 16 RCTs (interquartile range = 12-21) included in each meta-analysis. The standardized effect size was negative at the 1st percentile (- 0.29, favouring nalmefene) and positive at the 99th percentile (0.29, favouring naltrexone). A total of 7.1% (425/5961) of the meta-analyses with a negative effect size and 18.9% (616/3255) of those with a positive effect size were statistically significant (p < 0.05).

CONCLUSIONS

The choice of inclusion/exclusion criteria and analytical models for meta-analysis can result in entirely opposite results. VoE evaluations could be performed when overlapping meta-analyses on the same topic yield contradictory result.

TRIAL REGISTRATION

This study was registered on October 19, 2016, in the Open Science Framework (OSF, protocol available at https://osf.io/7bq4y/ ).

Adding Psychotherapy to the Naltrexone Treatment of Alcohol Use Disorder: Meta-analytic Review

Background

It remains unclear if naltrexone combined with psychotherapy is superior to naltrexone alone in treating alcohol use disorders (AUD). The current meta-analysis examined the hypothesis that psychotherapy is a significant moderator that influences AUD-related outcomes and that naltrexone combined with psychotherapy is associated with significantly better AUD-related outcomes than naltrexone alone.

Methods

A total of 30 studies (N_naltrexone = 2317; N_placebo = 2056) were included. Random effects model meta-analyses were carried out for each of the studied outcomes. Subsequently, the random effects model pooled estimates from studies with and without psychotherapy were compared using a Wald test. A mixed-effect model, incorporating psychotherapy as a moderator, was used to examine the impact of psychotherapy on treatment outcomes.

Results

Naltrexone had a significant treatment effect on abstinence relapse and Gamma-Glutamyl Transferase levels, but not cravings. The pooled estimates for studies with and without psychotherapy were not significantly different for any of the studied outcomes. Psychotherapy was not a significant moderator in the mixed effects models for any of the studied outcomes.

Conclusions

Naltrexone treatment is efficacious in reducing alcohol consumption, but not reducing cravings. Adding psychotherapy on top naltrexone did not result in any significant additional benefit for AUD patients.

Implementation of a Process for Initiating Naltrexone in Patients Hospitalized for Alcohol Detoxification or Withdrawal

BACKGROUND

Naltrexone trials have demonstrated improved outcomes for patients with alcohol use disorders. Hospital initiation of naltrexone has had limited study.

OBJECTIVE

To describe the implementation and impact of a process for counseling hospitalized patients with alcohol withdrawal about naltrexone.

DESIGN

A pre-post study analysis.

SETTING

A tertiary academic center.

PATIENTS

Patients hospitalized for alcohol withdrawal.

INTERVENTION

(1) Provider education about the efficacy and contraindications of naltrexone and (2) algorithms for evaluating patients for naltrexone.

MEASUREMENTS

The percentages of patients counseled about and prescribed naltrexone before discharge and the percentages of pre- and postintervention patients with 30-day emergency department (ED) revisits and rehospitalizations.

RESULTS

We identified 128 patient encounters before and 114 after implementation. The percentage of patients counseled about naltrexone rose from 1.6% preimplementation to 63.2% postimplementation (P<.001); the percentage of patients prescribed naltrexone rose from 1.6% to 28.1% (P<.001). Comparing preintervention versus postintervention groups, there were no unadjusted differences in 30-day ED revisits (25.8% vs 19.3%; P=.23) or rehospitalizations (10.2% vs 11.4%; P=.75). When adjusted for demographics and comorbidities, postintervention patients had lower odds of 30-day ED revisits (odds ratio [OR]=0.47; 95% confidence interval [CI], 0.24-0.94) but no significant difference in rehospitalizations (OR=0.76; 95% CI, 0.30-1.92). In subgroup analysis, postintervention patients counseled versus those not counseled about naltrexone were less likely to have 30-day ED revisits (9.7% vs 35.7%; P=.001) and rehospitalizations (2.8% vs 26.2%; P<.001).

CONCLUSIONS

The implementation of a process for counseling patients hospitalized for alcohol withdrawal about using naltrexone for the maintenance of sobriety was associated with lower 30-day ED revisits but no statistically significant difference in rehospitalizations.

Medications development for the treatment of alcohol use disorder: insights into the predictive value of animal and human laboratory models

Development of effective treatments for alcohol use disorder (AUD) represents an important public health goal. This review provides a summary of completed preclinical and clinical studies testing pharmacotherapies for the treatment of AUD. We discuss opportunities for improving the translation from preclinical findings to clinical trial outcomes, focusing on the validity and predictive value of animal and human laboratory models of AUD. Specifically, while preclinical studies of medications development have offered important insights into the neurobiology of the disorder and alcohol's molecular targets, limitations include the lack of standardized methods and streamlined processes whereby animal studies can readily inform human studies. Behavioral pharmacology studies provide a less expensive and valuable opportunity to assess the feasibility of a pharmacotherapy prior to initiating larger scale clinical trials by providing insights into the mechanism of the drug, which can then inform recruitment, analyses, and assessments. Summary tables are provided to illustrate the wide range of preclinical, human laboratory, and clinical studies of medications development for alcoholism. Taken together, this review highlights the challenges associated with animal paradigms, human laboratory studies, and clinical trials with the overarching goal of advancing treatment development and highlighting opportunities to bridge the gap between preclinical and clinical research.

Mice expressing a "hyper-sensitive" form of the CB1 cannabinoid receptor (CB1) show modestly enhanced alcohol preference and consumption

We recently characterized S426A/S430A mutant mice expressing a desensitization-resistant form of the CB1 receptor. These mice display an enhanced response to endocannabinoids and ∆9-THC. In this study, S426A/S430A mutants were used as a novel model to test whether ethanol consumption, morphine dependence, and reward for these drugs are potentiated in mice with a "hyper-sensitive" form of CB1. Using an unlimited-access, two-bottle choice, voluntary drinking paradigm, S426A/S430A mutants exhibit modestly increased intake and preference for low (6%) but not higher concentrations of ethanol. S426A/S430A mutants and wild-type mice show similar taste preference for sucrose and quinine, exhibit normal sensitivity to the hypothermic and ataxic effects of ethanol, and have normal blood ethanol concentrations following administration of ethanol. S426A/S430A mutants develop robust conditioned place preference for ethanol (2 g/kg), morphine (10 mg/kg), and cocaine (10 mg/kg), demonstrating that drug reward is not changed in S426A/S430A mutants. Precipitated morphine withdrawal is also unchanged in opioid-dependent S426A/S430A mutant mice. Although ethanol consumption is modestly changed by enhanced CB1 signaling, reward, tolerance, and acute sensitivity to ethanol and morphine are normal in this model.

Kappa-opioid receptors differentially regulate low and high levels of ethanol intake in female mice

INTRODUCTION

Studies in laboratory animals and humans indicate that endogenous opioids play an important role in regulating the rewarding value of various drugs, including ethanol (EtOH). Indeed, opioid antagonists are currently a front-line treatment for alcoholism in humans. Although roles for mu- and delta-opioid receptors have been characterized, the contribution of kappa-opioid receptors (KORs) is less clear. There is evidence that changes in KOR system function can decrease or increase EtOH drinking, depending on test conditions. For example, female mice lacking preprodynorphin - the precursor to the endogenous KOR ligand dynorphin - have reduced EtOH intake. Considering that KORs can regulate dopamine (DA) transmission, we hypothesized that KORs expressed on DA neurons would play a prominent role in EtOH intake in females.

METHODS

We used a Cre/loxP recombination strategy to ablate KORs throughout the body or specifically on dopamine uptake transporter (DAT)-expressing neurons to investigate the role of KORs on preference for and intake of EtOH (2-bottle choice), the transition from moderate to excessive EtOH drinking (intermittent EtOH access), and binge EtOH drinking (drinking in the dark [DID]).

RESULTS

KOR deletion decreased preference for EtOH, although this effect was less pronounced when EtOH intake increased beyond relatively low levels.

DISCUSSION

Our findings indicate that KOR activation increases EtOH drinking via effects mediated, at least in part, by KORs on DA neurons. While the mechanisms of this regulation remain unknown, previous work suggests that alterations in negative reinforcement processes or sensitivity to the sensory properties of EtOH can affect preference and intake.

Naltrexone: A Pan-Addiction Treatment?

Addiction is a major public health problem with few efficacious and safe treatments. The goal of this review is to provide an evidence-based assessment of the therapeutic role of the opioid antagonist naltrexone across the addiction spectrum-substance-based and behavioral. The PubMed database was searched for randomized, placebo-controlled clinical trials that investigated the oral or intramuscular long-acting formulation of naltrexone in substance use disorders or behavioral addictions such as pathological gambling, kleptomania, and trichotillomania. Thirty-nine efficacy studies were retrieved, covering alcohol use disorder (n = 22), opioid use disorder (n = 6), nicotine use disorder (n = 5), stimulant use disorder (n = 2), gambling disorder (n = 2), trichotillomania (n = 1), and kleptomania (n = 1). Despite the very different presentations within and between both addiction categories, the data, as a whole, show consistency in favor of naltrexone's relative efficacy and safety. Given the potential benefit and good tolerability revealed in the studies, the high morbidity associated with addiction, and the dearth of alternate treatments, naltrexone would seem like an underutilized treatment option. Further, naltrexone's seemingly broad anti-addiction efficacy supports a shared role for brain opioid pathways in the pathophysiology of addiction, broadly defined. More studies investigating the efficacy and tolerability of naltrexone and other opioid modulators are warranted. Studies should also further examine the effect of combining psychotherapy with naltrexone, as well as the potential role of naltrexone in treating comorbid addictions.

Current insights into the mechanisms and development of treatments for heavy drinking cigarette smokers

There is a strong association between cigarette smoking and alcohol use at the epidemiological, behavioral, and molecular levels, and this co-use creates substantial impediments to smoking cessation among smokers who are also heavy drinkers. Compared with individuals who only smoke, those who both drink and smoke heavily experience more severe health consequences and have greater difficulty in quitting smoking. During smoking abstinence, greater alcohol use is associated with decreased odds of smoking cessation, and smokers are substantially more likely to experience a smoking lapse during drinking episodes. As heavy drinking smokers are less responsive to the currently available pharmacological treatments, this subgroup of high-risk substance users possesses a unique clinical profile and treatment needs. Thus, treatment development for heavy drinking smokers represents a significant and understudied research area within the field of smoking cessation. This review will briefly describe findings from epidemiological, behavioral, and molecular studies illustrating alcohol and tobacco co-use and identify how the behavioral and neurobiological mechanisms underlying the interaction of alcohol and nicotine may inform the development of targeted treatments for this unique population of smokers.

Roles for the endocannabinoid system in ethanol-motivated behavior

Alcohol use disorder represents a significant human health problem that leads to substantial loss of human life and financial cost to society. Currently available treatment options do not adequately address this human health problem, and thus, additional therapies are desperately needed. The endocannabinoid system has been shown, using animal models, to modulate ethanol-motivated behavior, and it has also been demonstrated that chronic ethanol exposure can have potentially long-lasting effects on the endocannabinoid system. For example, chronic exposure to ethanol, in either cell culture or preclinical rodent models, causes an increase in endocannabinoid levels that results in down-regulation of the cannabinoid receptor 1 (CB1) and uncoupling of this receptor from downstream G protein signaling pathways. Using positron emission tomography (PET), similar down-regulation of CB1 has been noted in multiple regions of the brain in human alcoholic patients. In rodents, treatment with the CB1 inverse agonist SR141716A (Rimonabant), or genetic deletion of CB1 leads to a reduction in voluntary ethanol drinking, ethanol-stimulated dopamine release in the nucleus accumbens, operant self-administration of ethanol, sensitization to the locomotor effects of ethanol, and reinstatement/relapse of ethanol-motivated behavior. Although the clinical utility of Rimonabant or other antagonists/inverse agonists for CB1 is limited due to negative neuropsychiatric side effects, negative allosteric modulators of CB1 and inhibitors of endocannabinoid catabolism represent therapeutic targets worthy of additional examination.

The efficacy of acamprosate and naltrexone in the treatment of alcohol dependence, Europe versus the rest of the world: a meta-analysis

AIMS

To determine the efficacy of acamprosate and naltrexone in the treatment of those who are alcohol-dependent in reducing lapse/relapse to alcohol consumption and treatment discontinuation, and to examine whether a proportion of the variance in study outcome can be explained by the country in which the trials have taken place.

METHOD

A systematic review and meta-analysis of randomized controlled trials published before September 2013 was conducted. The primary outcome measures were the efficacy of acamprosate or naltrexone in reducing lapse/relapse compared to placebo in the treatment of alcohol dependence and treatment discontinuation. Twenty-two randomized controlled trials (RCTs) of the efficacy of acamprosate met inclusion criteria for the meta-analysis, with a total of 2649 participants in the acamprosate group and 2587 in the placebo group. Twenty-seven RCTs of the efficacy of naltrexone met inclusion criteria for the meta-analysis, with a total of 2253 participants in the naltrexone group and 1946 in the placebo group. A random-effects model using a Mantel-Haenszel method was applied to conduct the meta-analysis. Variance in study outcomes was explored using subgroup analysis of Europe versus the rest of the world (ROW).

RESULTS

The risk of returning to any drinking at 6 months was significantly lower for acamprosate [risk ratio (RR) = 0.83, 95% confidence interval (CI) = 0.78-0.89]. There was little difference in the risk of participants discontinuing treatment for any reason (RR = 0.91, 95% CI = 0.83-1.00) or due to adverse events (RR = 1.30, 95% CI = 0.96-1.75) for the acamprosate compared to placebo groups. The risk of individuals returning to any drinking at approximately 3 months was reduced significantly for the naltrexone group (RR = 0.92, 95% CI = 0.86-1.00), as was the risk of individuals relapsing to heavy drinking at 3 months (RR = 0.85, 95% CI = 0.78-0.93). There was no significant difference between naltrexone and placebo for the risk of individuals discontinuing treatment for any reason (RR = 0.94, 95% CI = 0.84-1.05). There was a significantly greater risk of participants in the naltrexone group discontinuing treatment due to adverse events compared to placebo (RR = 1.72, 95% CI = 1.10-2.70). Subgroup analysis by country (Europe versus ROW) revealed no difference in risk between acamprosate and placebo for the outcomes returning to any drinking at 6 months and discontinuing treatment due to adverse events. For the outcome discontinuation of treatment for any reason, there was a significant difference in RR between Europe and the ROW (χ(2)  = 11.65, P <0.001) for acamprosate. Acamprosate was associated with a reduction in risk of discontinuing treatment for Europe (RR = 0.86, 95% CI = 0.79-0.95), but an increase in risk of discontinuing treatment for ROW (RR = 1.23, 95% CI = 1.03-1.48).

CONCLUSIONS

Both acamprosate and naltrexone appear to reduce the risk of individuals returning to drinking alcohol in those who are alcohol-dependent. The country in which a randomized control trial (RCT) for the efficacy of acamprosate and naltrexone is completed does not appear to explain the variance in trial outcomes for returning to drinking alcohol or discontinuing drinking due to adverse effects. However, the country in which the RCT of acamprosate are completed may be important for explaining the variance between studies for the outcome 'discontinuing treatment for any reason'.

Neuropeptides: metabolism to bioactive fragments and the pharmacology of their receptors

The proteolytic processing of neuropeptides has an important regulatory function and the peptide fragments resulting from the enzymatic degradation often exert essential physiological roles. The proteolytic processing generates, not only biologically inactive fragments, but also bioactive fragments that modulate or even counteract the response of their parent peptides. Frequently, these peptide fragments interact with receptors that are not recognized by the parent peptides. This review discusses tachykinins, opioid peptides, angiotensins, bradykinins, and neuropeptide Y that are present in the central nervous system and their processing to bioactive degradation products. These well-known neuropeptide systems have been selected since they provide illustrative examples that proteolytic degradation of parent peptides can lead to bioactive metabolites with different biological activities as compared to their parent peptides. For example, substance P, dynorphin A, angiotensin I and II, bradykinin, and neuropeptide Y are all degraded to bioactive fragments with pharmacological profiles that differ considerably from those of the parent peptides. The review discusses a selection of the large number of drug-like molecules that act as agonists or antagonists at receptors of neuropeptides. It focuses in particular on the efforts to identify selective drug-like agonists and antagonists mimicking the effects of the endogenous peptide fragments formed. As exemplified in this review, many common neuropeptides are degraded to a variety of smaller fragments but many of the fragments generated have not yet been examined in detail with regard to their potential biological activities. Since these bioactive fragments contain a small number of amino acid residues, they provide an ideal starting point for the development of drug-like substances with ability to mimic the effects of the degradation products. Thus, these substances could provide a rich source of new pharmaceuticals. However, as discussed herein relatively few examples have so far been disclosed of successful attempts to create bioavailable, drug-like agonists or antagonists, starting from the structure of endogenous peptide fragments and applying procedures relying on stepwise manipulations and simplifications of the peptide structures.

Pharmacological Options for Smoking Cessation in Heavy-Drinking Smokers

There is a high prevalence of comorbid tobacco use and alcohol use disorder (AUD), affecting more than 6 million people in the US. Globally, tobacco and alcohol use rank fourth and fifth, respectively, for disability-adjusted life-years lost. Levels of alcohol use are higher in smokers than nonsmokers, and the prevalence of smoking is higher in heavy drinkers compared with nondrinkers. This relationship is driven by many different factors, including genetics, neurobiological mechanisms, conditioning processes, and psychosocial influences. Although this unique population tends to experience more negative health consequences, more severe AUD, and poorer response to treatment than those with either AUD or tobacco use disorder alone, there are currently no available treatment protocols tailored to this comorbid condition. In this review, we provide a comprehensive review of ongoing clinical research into smoking cessation options for heavy-drinking smokers (HDS) through an evaluation of the effect of promising novel pharmacotherapies as well as combination therapies, including varenicline, naltrexone, the combination of varenicline and naltrexone, and the combination of naltrexone and nicotine replacement therapy (NRT). These treatments are considered in light of the standard of care for smoking cessation, and seek to improve upon the available guidelines for this sizeable subgroup of smokers, namely those smokers who drink heavily.

Varenicline, low dose naltrexone, and their combination for heavy-drinking smokers: human laboratory findings

RATIONALE

Heavy-drinking smokers constitute a sizeable and hard-to-treat subgroup of smokers, for whom tailored smoking cessation therapies are not yet available.

OBJECTIVES

The present study used a double-blind, randomized, 2 × 2 medication design, testing varenicline alone (VAR; 1 mg twice daily), low dose naltrexone alone (L-NTX; 25 mg once daily), varenicline plus naltrexone, and placebo for effects on cigarette craving and subjective response to alcohol and cigarettes in a sample (n = 130) of heavy-drinking daily smokers (≥10 cigarettes/day).

METHODS

All participants were tested after a 9-day titration period designed to reach a steady state on the target medication. Testing was completed at 12 h of nicotine abstinence, after consuming a standard dose of alcohol (target breath alcohol concentration = 0.06 g/dl) and after smoking the first cigarette of the day.

RESULTS

The combination of VAR + L-NTX was superior to placebo, and at times superior to monotherapy, in attenuating cigarette craving, cigarette and alcohol "high," and in reducing ad-lib consumption of both cigarettes and alcohol during the 9-day medication titration period.

CONCLUSIONS

These preliminary findings indicate that clinical studies of the combination of VAR + L-NTX for heavy drinkers trying to quit smoking are warranted and may ultimately improve clinical care for this sizeable and treatment-resistant subgroup of smokers.

Pharmacogenetics of addiction therapy

Drug addiction is a serious relapsing disease that has high costs to society and to the individual addicts. Treatment of these addictions is still in its nascency, with only a few examples of successful therapies. Therapeutic response depends upon genetic, biological, social, and environmental components. A role for genetic makeup in the response to treatment has been shown for several addiction pharmacotherapies. For several addiction pharmacotherapies, response to treatment varies based on individual genetic makeup. In this chapter, we discuss the role of genetics in pharmacotherapies, specifically for cocaine, alcohol, and opioid dependences. The elucidation of the role of genetics should aid in the development of new treatments and increase the efficacy of existing treatments.

Treating obesity: is it all in the gut?

Obesity is a leading cause of preventable mortality worldwide, with current strategies for treatment including life-style changes, pharmacological intervention and bariatric surgery. With pharmacological intervention showing at best modest patient benefits, new treatments are required. Modulation of anorectic gut hormones could offer the potential to elicit the required life-changing level of efficacy only currently seen with bariatric surgery, and without the cardiovascular risk associated with a number of the current marketed therapies. This review will discuss the gut hormones glucagon-like peptide-1 (GLP-1), Ghrelin and cholecystokinin (CCK)--for which more advanced non-peptide chemical matter has been discovered acting through these hormone pathways and/or their receptors.

Improving clinical outcomes for naltrexone as a management of problem alcohol use

Despite being a relatively effective and safe treatment, the clinical management of alcohol abuse/dependence by oral naltrexone can be compromised due to the patient's non-compliance with daily use of this medication. Over the past decade an increasing body of research has suggested that the use of sustained release depot naltrexone preparations can overcome this issue and deliver improved clinical outcomes. However, at the same time, research findings from diverse areas of pharmacogenetics, neurobiology and behavioural psychology have also been converging to identify variables including genetic markers, patient psychosocial characteristics and drug use history differences, or clusters of these variables that play a major role in mediating the response of alcohol abuse/dependent persons to treatment by naltrexone. While this article does not attempt to review all available data pertaining to an individual alcohol dependent patient's response to treatment by naltrexone, it does identify relevant research areas and highlights the importance of data arising from them. The characterization of clinical markers, to identify those patients who are most likely to benefit from naltrexone and to tailor a more individual naltrexone treatment, will ultimately provide significant benefit to both patients and clinicians by optimizing treatment outcome.

Naltrexone (50 mg) plus psychotherapy in alcohol-dependent patients: a meta-analysis of randomized controlled trials

BACKGROUND

Alcoholism is a chronic and potentially fatal disease. One of the therapeutic options is pharmacotherapy with the opioid antagonist naltrexone in combination with psychotherapy.

OBJECTIVES

The objective of this review was to compare the clinical effectiveness of naltrexone (50 mg/day) versus that of a placebo in alcohol-dependent patients receiving psychotherapy.

METHODS

The clinical effectiveness of the treatment was assessed in accordance with the principles of systematic review, as outlined in the Cochrane Collaboration guidelines (Cochrane Reviewer's Handbook) and the guidelines of the Polish Agency for Health Technology Assessment (AHTAPol).

RESULTS

Statistical significances in favor of the treatment modality were found in both the percentage of patients maintaining total abstinence and the percentage of relapsed patients.

CONCLUSION

The analysis herein demonstrates that for short (12-16 weeks) period of treatment, a combination of naltrexone administration and psychotherapy results in high clinical efficacy with a safety profile comparable to that of the placebo in the treatment of alcohol-dependent patients. The side effects of naltrexone treatment are usually mild and transient.

Placebo group improvement in trials of pharmacotherapies for alcohol use disorders: a multivariate meta-analysis examining change over time

OBJECTIVE

Placebo group improvement in pharmacotherapy trials has been increasing over time across several pharmacological treatment areas. However, it is unknown to what degree increasing improvement has occurred in pharmacotherapy trials for alcohol use disorders or what factors may account for placebo group improvement. This meta-analysis of 47 alcohol pharmacotherapy trials evaluated (1) the magnitude of placebo group improvement, (2) the extent to which placebo group improvement has been increasing over time, and (3) several potential moderators that might account for variation in placebo group improvement.

METHOD

Random-effects univariate and multivariate analyses were conducted that examined the magnitude of placebo group improvement in the 47 studies and several potential moderators of improvement: (a) publication year, (b) country in which the study was conducted, (c) outcome data source/type, (d) number of placebo administrations, (e) overall severity of study participants, and (f) additional psychosocial treatment.

RESULTS

Substantial placebo group improvement was found overall and improvement was larger in more recent studies. Greater improvement was found on moderately subjective outcomes, with more frequent administrations of the placebo, and in studies with greater participant severity of illness. However, even after controlling for these moderators, placebo group improvement remained significant, as did placebo group improvement over time.

CONCLUSIONS

Similar to previous pharmacotherapy placebo research, substantial pretest to posttest placebo group improvement has occurred in alcohol pharmacotherapy trials, an effect that has been increasing over time. However, several plausible moderator variables were not able to explain why placebo group improvement has been increasing over time.

The placebo effect in clinical trials for alcohol dependence: an exploratory analysis of 51 naltrexone and acamprosate studies

BACKGROUND

The placebo effect often undermines efforts to determine treatment effectiveness in clinical trials. A significant placebo response occurs in alcohol trials, but it is not well understood. The purpose of this study was to characterize the placebo response across multiple naltrexone and acamprosate studies.

METHODS

Fifty-one trials, 3 with a naltrexone and an acamprosate arm, 31 with at least 1 naltrexone arm, and 17 with at least 1 acamprosate arm, were identified from Cochrane reviews and PubMed search. To be included in this study, patients had to be at least 18 years old, abstinent from alcohol before randomization, and meet a diagnosis of alcohol dependence. Pearson correlation coefficients (rp ) and simple linear regression were used to describe the strength of linear relationships between placebo response and treatment effect size. Spearman's rank correlation coefficients (rs ) were used to examine the strength of associations between study characteristics and placebo response.

RESULTS

For the end point measures of percent days abstinent and total abstinence, a negative relationship was evident between placebo response and treatment effect size in the naltrexone trials (rp  = -0.55, p < 0.01 and rp  = -0.20, p = 0.35, respectively) as well as in the acamprosate trials (rp  = -0.45, p = 0.09 and rp  = -0.56, p = 0.01, respectively). The placebo response for percent days abstinent was negatively correlated with mean age of participants (rs  = -0.42, p = 0.05) across naltrexone trials and positively correlated with publication year (rs  = 0.57, p = 0.03) across acamprosate trials. However, these 2 study characteristics were not significantly correlated with treatment effect size.

CONCLUSIONS

The placebo response varied considerably across trials and was negatively correlated with the treatment effect size. Additional studies are required to fully understand the complex nature of the placebo response and to evaluate approaches to minimize its effects.

PODSE: a computer program for optimal design of trials with discrete-time survival endpoints

In experimental settings, one or more groups of subjects receive a treatment and they are compared to a group of subjects that receives a standard treatment or no treatment at all. These compared groups might have an equal number of subjects or some of the groups might have more participants relative to the other groups. Moreover, subjects in these groups can be followed over a short or a long period. To conduct experiments in a sufficient way, researchers should find a good design in the planning phase of the trial. The optimal design for experimental studies on event occurrence with discrete-time survival endpoints where two treatment groups are followed over time, is an optimal combination of the number of time periods, the total number of participants in the trial and the proportion of subjects in the experimental group. It is easy to find the best design for such studies using the PODSE program.

Meta-analysis of naltrexone and acamprosate for treating alcohol use disorders: when are these medications most helpful?

AIMS

Although debates over the efficacy of oral naltrexone and acamprosate in treating alcohol use disorders tend to focus on their global efficacy relative to placebo or their efficacy relative to each other, the underlying reality may be more nuanced. This meta-analysis examined when naltrexone and acamprosate are most helpful by testing: (i) the relative efficacy of each medication given its presumed mechanism of action (reducing heavy drinking versus fostering abstinence) and (ii) whether different ways of implementing each medication (required abstinence before treatment, detoxification before treatment, goal of treatment, length of treatment, dosage) moderate its effects.

METHODS

A systematic literature search identified 64 randomized, placebo-controlled, English-language clinical trials completed between 1970 and 2009 focused on acamprosate or naltrexone.

RESULTS

Acamprosate had a significantly larger effect size than naltrexone on the maintenance of abstinence, and naltrexone had a larger effect size than acamprosate on the reduction of heavy drinking and craving. For naltrexone, requiring abstinence before the trial was associated with larger effect sizes for abstinence maintenance and reduced heavy drinking compared with placebo. For acamprosate, detoxification before medication administration was associated with better abstinence outcomes compared with placebo.

CONCLUSIONS

In treatment for alcohol use disorders, acamprosate has been found to be slightly more efficacious in promoting abstinence and naltrexone slightly more efficacious in reducing heavy drinking and craving. Detoxification before treatment or a longer period of required abstinence before treatment is associated with larger medication effects for acamprosate and naltrexone respectively.

Do manualized psychosocial interventions help reduce relapse among alcohol-dependent adults treated with naltrexone or placebo? A meta-analysis

BACKGROUND

 During the past decade, several novel medication treatments and psychosocial interventions have been tested. Overall, their impact on reducing alcohol use and preventing relapse has been modest. These outcomes have spurred researchers to investigate whether the addition of manualized psychosocial therapies with demonstrated efficacy to pharmacotherpy would have a synergistic effect.

OBJECTIVES

 We conducted a meta-analysis to test the hypothesis that the addition of manualized psychosocial therapies would reduce the frequency of relapse.

RESULTS

 This review analyzed data from six studies. Among studies that used random assignment to manually guided psychosocial interventions, the rates of relapse between the naltrexone plus a psychosocial intervention and naltrexone without a psychosocial intervention were very similar. Among patients allocated to placebo, similar rates of relapse were also found between Cognitive Behavioral Therapy (CBT) and non-CBT. In studies which used manualized psychotherapies as a platform, relapse rates were similar between naltrexone and placebo. In contrast, studies using Treatment As Usual psychotherapy as a platform demonstrated lower rates of relapse in the naltrexone group, compared to placebo group.

CONCLUSIONS

 We conclude that CBT does not appear to offer benefits beyond those derived from study medications.

SCIENTIFIC SIGNIFICANCE

 The benefit of the addition of CBT to medication in preventing relapse may be limited.

Delta and kappa opioid receptor polymorphisms influence the effects of naltrexone on subjective responses to alcohol

Naltrexone, one of four FDA-approved pharmacotherapies for alcohol dependence, has shown moderate efficacy in clinical trials. Pharmacogenetic effects have been reported such that allelic variation at the gene encoding the mu-opioid receptor (OPRM1, rs1799971) predicts naltrexone-induced blunting of the positively reinforcing effects of alcohol. However, naltrexone also binds, albeit to a lesser degree, to kappa and delta opioid receptors in the brain. This alternate binding presents the possibility that single nucleotide polymorphisms (SNPs) in the kappa and delta opioid receptor (OPRK1 and OPRD1) genes may contribute to naltrexone pharmacogenetics. Therefore, the goal of this exploratory study was to re-examine data from a double-blind placebo controlled laboratory trial of naltrexone for pharmacogenetic effects at kappa and delta opioid receptor tag SNPs. Participants were 40 heavy drinkers (12 female) who underwent an intravenous alcohol challenge paradigm after receiving naltrexone (50mg) or placebo in randomized and crossover fashion. Dependent variables were self-reported alcohol-induced stimulation, sedation, and craving. Multilevel models revealed a significant Naltrexone×OPRK1 Genotype (rs997917) interaction predicting alcohol-induced sedation, such that TT homozygotes reported lower naltrexone-induced alcohol sedation as compared to carriers of the C allele. Moreover, there was a significant Naltrexone×OPRD1 Genotype (rs4654327) interaction predicting alcohol-induced stimulation and craving, such that carriers of the A allele at this locus reported greater naltrexone-induced blunting of alcohol stimulation and alcohol craving compared to GG homozygotes. These findings suggest that additional pharmacogenetic effects in the opioid receptor system may account for individual differences in response to naltrexone in the human laboratory.

Understanding naltrexone mechanism of action and pharmacogenetics in Asian Americans via behavioral economics: a preliminary study

A behavioral economic approach to understanding the relative value of alcohol may be useful for advancing medication development for alcoholism. Naltrexone is a heavily researched and moderately effective treatment for alcohol dependence making it a good candidate for a proof-of-concept study of behavioral economics and alcoholism pharmacotherapy. This study examines naltrexone efficacy and pharmacogenetics in terms of the relative value of alcohol, assessed via demand curve analysis. Participants were 35 heavy drinking (AUDIT ≥8) Asian Americans. A within-subjects cross-over medication design was used along with an intravenous alcohol challenge completed after 4 days of both naltrexone and placebo. At baseline and BrAC = 0.06g/dl, participants completed an Alcohol Purchase Task, which assessed estimated alcohol consumption along escalating prices. Behavioral economic demand curve analysis yielded measures of intensity, elasticity, maximum expenditure (O(max)), proportionate price insensitivity (P(max)) and breakpoint. Compared to placebo, naltrexone significantly reduced intensity, O(max) and breakpoint. There were also trend-level medication effects on P(max). BrAC was associated with increases in P(max) and breakpoint. A significant naltrexone × OPRM1 genotype interaction was observed for intensity of demand. The present study extends the literature on naltrexone's mechanisms through the application of a novel behavioral economic paradigm. These results indicate that naltrexone reduces several indices of demand for alcohol. This preliminary report provides further evidence for the effectiveness of naltrexone and supports the utility of a behavioral economic approach to alcoholism pharmacotherapy development.

A randomized clinical trial of naltrexone and behavioral therapy for problem drinking men who have sex with men

OBJECTIVE

This study tested the comparative effectiveness of modified behavioral self-control therapy (MBSCT) and naltrexone (NTX), as well as the added benefit of combining the 2, in problem drinking men who have sex with men (MSM) seeking to reduce but not quit drinking.

METHOD

Participants (N = 200) were recruited and urn randomized to 1 of 2 medication conditions, NTX or placebo (PBO), and either MSBCT or no behavioral intervention, yielding 4 conditions: PBO, NTX, MSBCT, and NTX + MSBCT. In addition, all participants received a brief medication compliance intervention. Participants were treated for 12 weeks and assessed 1 week after treatment completion. Two primary outcomes-sum of standard drinks and number of heavy drinking days-and 1 secondary outcome-percentage of those drinking in a nonhazardous manner (NoH)-were selected a priori.

RESULTS

There was a significant main effect for MBSCT (all ps < .01) but not NTX on all 3 outcomes. In addition, the combination of NTX and MBSCT was not more effective than either MSCBT or PBO. There was a significant interaction effect on NoH, such that NTX significantly increased the likelihood (odds ratio = 3.3) of achieving a nonhazardous drinking outcome relative to PBO. In addition, NTX was significantly more effective than PBO on a descriptive outcome: negative consequences of drinking.

CONCLUSIONS

There was no advantage to adding NTX to MBSCT. In addition, MBSCT showed stronger evidence of efficacy than NTX. At the same time, NTX delivered in the context of a minimal medication compliance intervention was significantly more effective than PBO on an important clinical indicator. Results provide new information to guide the treatment of problem drinking, including in primary care settings.

Pharmacogenetics of naltrexone in asian americans: a randomized placebo-controlled laboratory study

Recent clinical and laboratory studies have shown that the effects of naltrexone for alcoholism may be moderated by the Asn40Asp single-nucleotide polymorphism (SNP) of the μ-opioid receptor gene (OPRM1). Allele frequencies for this polymorphism, however, have been shown to vary substantially as a function of ethnic background, such that individuals of Asian descent are more likely to carry the minor (Asp40) allele. The objective of this study is to test the naltrexone pharmacogenetic effects of the Asn40Asp SNP in a sample of Asian Americans. This study consists of a double-blinded, randomized, placebo-controlled laboratory trial of naltrexone. Participants (n=35, 10 females; 13 Asn40Asn and 22 Asp40 carriers) were non-treatment-seeking heavy drinkers recruited from the community. After taking naltrexone or placebo, participants completed an intravenous alcohol administration session. The primary outcome measures were subjective intoxication and alcohol craving. Results suggested that Asp40 carriers experienced greater alcohol-induced sedation, subjective intoxication, and lower alcohol craving on naltrexone, as compared to placebo, and to Asn40 homozygotes. There results were maintained when controlling for ALDH2 (rs671) and ADH1B (rs1229984) markers and when examining the three levels of OPRM1 genotype, thereby supporting an OPRM1 gene dose response. These findings provide a much-needed extension of previous studies of naltrexone pharmacogenetics to individuals of Asian descent, an ethnic group more likely to express the minor allele putatively associated with improved biobehavioral and clinical response to this medication. These findings help further delineate the biobehavioral mechanisms of naltrexone and its pharmacogenetics.

Nondopaminergic treatments for Parkinson’s disease

SUMMARY The main treatment strategy for Parkinson’s disease (PD) is focused on dopamine replacement. However, PD is no longer seen purely as a disease of the dopaminergic system, as the pathological processes involve neurodegeneration and altered neurotransmission of several nondopaminergic systems that are involved in both motor and nonmotor features of the disease. This article reviews current and experimental nondopaminergic pharmacological approaches to treatments for PD with a focus on motor symptoms, treatments of L-dopa-induced motor complications and treatments of nonmotor symptoms including mood disorders, cognition, psychosis and autonomic problems.

Evolving therapeutic indications for N-type calcium channel blockers: from chronic pain to alcohol abuse

Clinical exploitation of the therapeutic potential of calcium channels has long been limited to L-type blockers for cardiovascular diseases. Recently, N-type blockers have been fully validated for the treatment of chronic pain, following approval of the intrathecally active ziconotide (Prialt(®)). This review describes the successful efforts to broaden the therapeutic scope of this mechanism to other major CNS indications, based on the discovery of N-type blockers orally active against pain. In animal models, the N-type blocker and pain-reducing NP078585 is efficacious against key elements of ethanol dependency, including self-administration and relapse. NP078585 moderately stimulates brain dopamine release without inducing reward or hyperlocomotion. N-type blockers may emerge as a novel class of 'dopamine stabilizers' for the treatment of drug dependency and other neuropsychiatric disorders without the side effects of current therapies.

Pharmacotherapy for substance abuse disorders in adolescence

The public health effects of adolescent substance abuse disorders (SUD) reaches further than the immediate intoxicating effects. Medications play a limited role in the treatment of youth beyond addressing short-term symptoms but may improve longer-term outcomes for some patients. Given the potential devastating consequences of SUD, clinicians should become familiar with all available treatment options. This article reviews the pharmacotherapy for adolescent SUD to inform clinicians considering the use of this modality for selected groups of patients.

Medical treatment of alcohol dependence: a systematic review

OBJECTIVE

To summarize published data on pharmacologic treatments for alcohol dependence alone and in combination with brief psychosocial therapies that may be feasible for primary care and specialty medical settings.

METHODS

We conducted electronic searches of published original research articles and reviews in MEDLINE, SCOPUS, CINAHL, Embase, and PsychINFO. In addition, hand searches of reference lists of review articles, supplemental searches of internet references and contacts with experts in the field were conducted. Randomized controlled studies published between January 1960 and August 2010 that met our inclusion/exclusion criteria were included.

RESULTS

A total of 85 studies, representing 18,937 subjects, met our criteria for inclusion. The evidence base for oral naltrexone (6% more days abstinent than placebo in the largest study) and topiramate (prescribed off-label) (e.g., 26.2% more days abstinent than placebo in a recent study) is positive but modest. Acamprosate shows modest efficacy with recently abstinent patients, with European studies showing better results than U.S. ones. The evidence-base for disulfiram is equivocal. Depot naltrexone shows efficacy (25% greater reduction in rate of heavy drinking vs. placebo, in one of the largest studies) in a limited number of studies. Some studies suggest that patients do better with extensive psychosocial treatments added to medications while others show that brief support can be equally effective.

CONCLUSIONS

Although treatment effects are modest, medications for alcohol dependence, in conjunction with either brief support or more extensive psychosocial therapy, can be effective in primary and specialty care medical settings.

Opioid antagonists for alcohol dependence

BACKGROUND

Alcohol dependence belongs to the globally leading health risk factors. Therapeutic success of psychosocial programs for relapse prevention is moderate and could be increased by an adjuvant treatment with the opioid antagonists naltrexone and nalmefene.

OBJECTIVES

To determine the effectiveness and tolerability of opioid antagonists in the treatment of alcohol dependence.

SEARCH STRATEGY

We searched the Cochrane Drugs and Alcohol Group (CDAG) Specialized Register, PubMed, EMBASE and CINAHL in January 2010 and inquired manufacturers and researchers for unpublished trials.

SELECTION CRITERIA

All double-blind randomised controlled trials (RCTs) which compare the effects of naltrexone or nalmefene with placebo or active control on drinking-related outcomes.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted outcome data. Trial quality was assessed by one author and cross-checked by a second author.

MAIN RESULTS

Based on a total of 50 RCTs with 7793 patients, naltrexone reduced the risk of heavy drinking to 83% of the risk in the placebo group RR 0.83 (95% CI 0.76 to 0.90) and decreased drinking days by about 4%, MD -3.89 (95% CI -5.75 to -2.04). Significant effects were also demonstrated for the secondary outcomes of the review including heavy drinking days, MD - 3.25 (95% CI -5.51 to -0.99), consumed amount of alcohol, MD - 10.83 (95% CI -19.69 to -1.97) and gamma-glutamyltransferase, MD - 10.37 (95% CI -18.99 to -1.75), while effects on return to any drinking, RR 0.96 (95 CI 0.92 to 1.00) missed statistical significance. Side effects of naltrexone were mainly gastrointestinal problems (e.g. nausea: RD 0.10; 95% CI 0.07 to 0.13) and sedative effects (e.g. daytime sleepiness: RD 0.09; 95% CI 0.05 to 0.14). Based on a limited study sample, effects of injectable naltrexone and nalmefene missed statistical significance. Effects of industry-sponsored studies, RR 0.90 (95% CI 0.78 to 1.05) did not significantly differ from those of non-profit funded trials, RR 0.84 (95% CI 0.77 to 0.91) and the linear regression test did not indicate publication bias (P = 0.765).

AUTHORS' CONCLUSIONS

Naltrexone appears to be an effective and safe strategy in alcoholism treatment. Even though the sizes of treatment effects might appear moderate in their magnitudes, these should be valued against the background of the relapsing nature of alcoholism and the limited therapeutic options currently available for its treatment.

Neuropsychiatric adverse effects of centrally acting antiobesity drugs

INTRODUCTION

Central neurochemical systems including the monoamine, opioid, and cannabinoid systems have been promising targets for antiobesity drugs that modify behavioral components of obesity. In addition to modulating eating behavior, centrally acting antiobesity drugs are also likely to alter emotional behavior and cognitive function due to the high expression of receptors for the neurochemical systems targeted by these drugs within the fronto-striatal and limbic circuitry.

METHODS

This paper reviewed the neuropsychiatric adverse effects of past and current antiobesity drugs, with a central mechanism of action, linking the adverse effects to their underlying neural substrates and neurochemistry.

RESULTS

Antiobesity drugs were found to have varying neuropsychiatric adverse event profiles. Insomnia was the most common adverse effect with drugs targeting monoamine systems (sibutramine, bupropion and tesofensine). These drugs had some positive effects on mood and anxiety and may have added therapeutic benefits in obese patients with comorbid depression and anxiety symptoms. Sedation and tiredness were the most common adverse effects reported with drugs targeting the m-opioid receptors (i.e., naltrexone) and combination therapies targeting the opioid and monoamine systems (i.e., Contrave™). Cognitive impairments were most frequently associated with the antiepileptic drugs, topiramate and zonisamide, consistent with their sedative properties. Drugs targeting the cannabinoid system (rimonabant and taranabant) were consistently associated with symptoms of anxiety and depression, including reports of suicidal ideation. Similar adverse events have also been noted for the D₁/D₅ antagonist ecopipam.

CONCLUSION

These findings highlight the need to assess neuropsychiatric adverse events comprehensively using sensitive and validated methods early in the clinical development of candidate antiobesity drugs with a central mechanism of action.

Emerging drugs to treat alcoholism

IMPORTANCE OF THE FIELD

Alcoholism is a widespread disorder with substantial mortality and negative treatment outcomes. To date, few medications have been found to reduce relapse rates or drinking in alcohol-dependent patients.

AREAS COVERED IN THIS REVIEW

This review focuses on drugs that have been clinically tested for the treatment of alcohol dependence in clinical trials, pilot trials or which are considered to have a clinical perspective. For this purpose, a detailed Medline search was conducted on this issue. Although the neurochemical basis of alcoholism and the neuronal circuitry mediating its psychotropic effects have been explored in great detail in recent years, few drugs have emerged for the treatment of alcohol dependence, also because pharmaceutical companies have only a limited interest in this area of research. Acamprosate and the opioid antagonist naltrexone have been found to be effective, although data are mixed. A depot formula of naltrexone and the alternate opioid antagonist nalmefene have been studied in clinical trials and will presumably be introduced in the markets soon. Other emerging drugs are topiramate, novel acetaldehyde dehydrogenase (ALDH) inhibitors, baclofen, a combination therapy of gababentin and flumazenil and drugs targeting the cortitropin-releasing factor/neuropeptide Y mediated stress axis.

WHAT THE READER WILL GAIN

Insights on the neurochemical basis of alcohol dependence and possible targets of medications.

TAKE HOME MESSAGE

Acamprosate, naltrexone and the ALDH inhibitor disulfiram are proven medications for the treatment of alcohol dependence with modest efficacy. Novel alternate medications, a depot formulation of the opioid antagonist naltrexone and another oral opioid antagonist, nalmefene, are available now with good evidence for clinical efficacy. Novel ALDH inhibitors, antiepileptic drugs such as topiramate and drugs targeting the stress axis are currently among the most promising emerging drugs.

The Effects of Naltrexone Among Alcohol Non-Abstainers: Results from the COMBINE Study

These analyses of the COMBINE Study examined the effects of naltrexone among non-abstainers. Given that one of the most well-established mechanisms of action of naltrexone involves blunting of alcohol reward, it is hypothesized that naltrexone should be more effective among individuals who drank during treatment. Participants were 952 (78% of the total COMBINE Study sample) treatment-seeking alcohol-dependent men and women who received pharmacotherapy for alcoholism and drank at least once during the 16-week trial. Mixed model analyses revealed that individuals who drank more regularly during the trial seemed to benefit most from naltrexone and the effects of naltrexone on heavy drinking was significant in treatment months 2 through 4 among individuals who reported drinking on 81, 68, and 60% or more of days, respectively. Those drinking frequencies were observed in 11, 15, and 19% of the sample. Similar effects were not observed for drinks per drinking day. These results suggest that a small subgroup of non-abstainers, composed primarily of very regular drinkers, appears to benefit from naltrexone in reducing heavy drinking days. Naltrexone may be effective in the context of controlled-drinking approaches, even among very frequent drinkers.

Anti-relapse medications: preclinical models for drug addiction treatment

Addiction is a chronic relapsing brain disease and treatment of relapse to drug-seeking is considered the most challenging part of treating addictive disorders. Relapse can be modeled in laboratory animals using reinstatement paradigms, whereby behavioral responding for a drug is extinguished and then reinstated by different trigger factors, such as environmental cues or stress. In this review, we first describe currently used animal models of relapse, different relapse triggering factors, and the validity of this model to assess relapse in humans. We further summarize the growing body of pharmacological interventions that have shown some promise in treating relapse to psychostimulant addiction. Moreover, we present an overview on the drugs tested in cocaine or methamphetamine addicts and examine the overlap of existing preclinical and clinical data. Finally, based on recent advances in our understanding of the neurobiology of relapse and published preclinical data, we highlight the most promising areas for future anti-relapse medication development.

A placebo-controlled randomized clinical trial of naltrexone in the context of different levels of psychosocial intervention

BACKGROUND

Naltrexone is approved for the treatment of alcohol dependence when used in conjunction with a psychosocial intervention. This study was undertaken to examine the impact of 3 types of psychosocial treatment combined with either naltrexone or placebo treatment on alcohol dependency over 24 weeks of treatment: (1) Cognitive-Behavioral Therapy (CBT) + medication clinic, (2) BRENDA (an intervention promoting pharmacotherapy) + medication clinic, and (3) a medication clinic model with limited therapeutic content.

METHODS

Two hundred and forty alcohol-dependent subjects were enrolled in a 24-week double-blind placebo-controlled study of naltrexone (100 mg/d). Subjects were also randomly assigned to 1 of 3 psychosocial interventions. All patients were assessed for alcohol use, medication adherence, and adverse events at regularly scheduled research visits.

RESULTS

There was a modest main treatment effect for the psychosocial condition favoring those subjects randomized to CBT. Intent-to-treat analyses suggested that there was no overall efficacy of naltrexone and no medication by psychosocial intervention interaction. There was a relatively low level of medication adherence (50% adhered) across conditions, and this was associated with poor outcome.

CONCLUSIONS

Results from this 24-week treatment study demonstrate the importance of the psychosocial component in the treatment of alcohol dependence. Moreover, results demonstrate a substantial association between medication adherence and treatment outcomes. The findings suggest that further research is needed to determine the appropriate use of pharmacotherapy in maximizing treatment response.