The neurobiology, clinical efficacy and safety of acamprosate in the treatment of alcohol dependence

Substance Use Disorder

Substance use disorders (SUDs) present a challenge in the emergency department (ED) setting. This article provides an overview of SUDs, their clinical assessment, legal considerations in drug testing, diagnosis, and treatment approaches. SUDs are prevalent and coexist with mental health disorders, necessitating comprehensive evaluation and management. Clinical assessment involves screening tools, substance use history, and identification of comorbidities. Diagnosis relies on a thorough evaluation of substance abuse patterns and associated medical conditions. Treatment approaches encompass a multidisciplinary approach, incorporating counseling, medications, and social support. Effective management of SUDs in the ED requires a comprehensive understanding of these complex disorders.

Adolescent alcohol drinking interaction with the gut microbiome: implications for adult alcohol use disorder

Reciprocal communication between the gut microbiota and the brain, commonly referred to as the "gut-brain-axis" is crucial in maintaining overall physiological homeostasis. Gut microbiota development and brain maturation (neuronal connectivity and plasticity) appear to be synchronized and to follow the same timeline during childhood (immature), adolescence (expansion) and adulthood (completion). It is important to note that the mesolimbic reward circuitry develops early on, whereas the maturation of the inhibitory frontal cortical neurons is delayed. This imbalance can lead to increased acquirement of reward-seeking and risk-taking behaviors during adolescence, and consequently eventuate in heightened risk for substance abuse. Thus, there is high initiation of alcohol drinking in early adolescence that significantly increases the risk of alcohol use disorder (AUD) in adulthood. The underlying causes for heightened AUD risk are not well understood. It is suggested that alcohol-associated gut microbiota impairment during adolescence plays a key role in AUD neurodevelopment in adulthood. Furthermore, alcohol-induced dysregulation of microglia, either directly or indirectly through interaction with gut microbiota, may be a critical neuroinflammatory pathway leading to neurodevelopmental impairments and AUD. In this review article, we highlight the influence of adolescent alcohol drinking on gut microbiota, gut-brain axis and microglia, and eventual manifestation of AUD. Furthermore, novel therapeutic interventions via gut microbiota manipulations are discussed briefly.

Plasma TNFSF10 levels associated with acamprosate treatment response in patients with alcohol use disorder

Acamprosate is an anti-craving drug used in alcohol use disorder (AUD) pharmacotherapy. However, only a subset of patients achieves optimal treatment outcomes. The identification of predictive biomarkers of acamprosate treatment response in patients with AUD would be a substantial advance in addiction medicine. We designed this study to use proteomics data as a quantitative biological trait as a step toward identifying inflammatory modulators that might be associated with acamprosate treatment outcomes. The NIAAA-funded Mayo Clinic Center for the Individualized Treatment of Alcoholism study had previously recruited 442 AUD patients who received 3 months of acamprosate treatment. However, only 267 subjects returned for the 3-month follow-up visit and, as a result, had treatment outcome information available. Baseline alcohol craving intensity was the most significant predictor of acamprosate treatment outcomes. We performed plasma proteomics using the Olink target 96 inflammation panel and identified that baseline plasma TNF superfamily member 10 (TNFSF10) concentration was associated with alcohol craving intensity and variation in acamprosate treatment outcomes among AUD patients. We also performed RNA sequencing using baseline peripheral blood mononuclear cells from AUD patients with known acamprosate treatment outcomes which revealed that inflammation-related pathways were highly associated with relapse to alcohol use during the 3 months of acamprosate treatment. These observations represent an important step toward advancing our understanding of the pathophysiology of AUD and molecular mechanisms associated with acamprosate treatment response. In conclusion, applying omics-based approaches may be a practical approach for identifying biologic markers that could potentially predict alcohol craving intensity and acamprosate treatment response.

Diagnosis and Management of Alcohol Use Disorder in Patients with Liver Disease: Lights and Shadows

Alcohol use disorder is the most common cause of advanced liver disease in the Western world. Diagnosis of alcohol use disorder can be difficult because patients with liver disease tend to deny alcohol intake for the fear of being excluded from treatment and because available biomarkers of alcohol intake have poor specificity in these patients. Alcohol abstinence is the cornerstone of the therapy in these patients. However, pharmacological treatments for alcohol use disorders have not been formally tested in patients with advanced liver disease, except for baclofen. Psychosocial intervention became crucial in these patients considering the limited pharmacological choice. However, psychosocial approach and an appropriate team to manage these patients are not still well defined. In this review, we critically discuss the diagnosis and the management of alcohol use disorder in patients with liver disease.

The Effect of Oral Administration of Black Sticky Rice with Giant Embryo on Brain GABA Concentrations

OBJECTIVE

Black sticky rice with giant embryo (BSRGE) contains high GABA content and affects alcohol-related indices among social drinkers, and alcohol intake and anxiety-related behavior of mice. However, it is unknown whether the intake of BSRGE affects GABAergic activity of brain directly. The purpose of this study is to elucidate the effect of oral administration of BSRGE on brain GABA concentrations compared with commercially available GABA compound and regular feeds.

METHODS

Twenty-one male C57BL/6 mice were assigned to BSRGE, a regular feed (AIN-76) lacking GABA, and a regular feed containing GABA compound. After feeding freely for 48 h, the cortex and striatum were separated from the brain. An enzyme-linked immunosorbent assay was conducted to measure GABA and glutamate concentrations in mouse brain.

RESULTS

The GABA concentration of the BSRGE group was higher than that of regular feed and GABA compound group (p<0.001). However, the GABA compound group showed no significant difference from the regular feed group (p=0.50).

CONCLUSION

Intake of BSRGE containing high GABA content increased GABA concentrations in mouse brain compared with regular feed unlike GABA compound. The results of this study constitute an important basis for further investigations into the clinical applications of BSRGE.

Cognitive effects of labeled addictolytic medications

INTRODUCTION

Alcohol, tobacco, and illegal drug usage is pervasive throughout the world, and abuse of these substances is a major contributor to the global disease burden. Many pharmacotherapies have been developed over the last 50years to target addictive disorders. While the efficacy of these pharmacotherapies is largely recognized, their cognitive impact is less known. However, all substance abuse disorders are known to promote cognitive disorders like executive dysfunction and memory impairment. These impairments are critical for the maintenance of addictive behaviors and impede cognitive behavioral therapies that are regularly administered in association with pharmacotherapies. It is also unknown if addictolytic medications have an impact on preexisting cognitive disorders, and if this impact is modulated by the indication of prescription, i.e. abstinence, reduction or substitution, or by the specific action of the medication.

METHOD

We reviewed the cognitive effects of labeled medications for tobacco addiction (varenicline, bupropion, nicotine patch and nicotine gums), alcohol addiction (naltrexone, nalmefene, baclofen, disulfiram, sodium oxybate, acamprosate), and opioid addiction (methadone, buprenorphine) in human studies. Studies were selected following MOOSE guidelines for systematic reviews of observational studies, using the keywords [Cognition] and [Cognitive disorders] and [treatment] for each medication.

RESULTS

971 articles were screened and 77 studies met the inclusion criteria and were reported in this review (for alcohol abuse, n=21, for tobacco n=22, for opioid n=34. However, very few comparative clinical trials have explored the chronic effects of addictolytic medications on cognition in addictive behaviors, and there are no clinical trials on the cognitive impact of nalmefene in patients suffering from alcohol use disorders.

DISCUSSION

Although some medications seem to enhance cognition in patients suffering from cognitive disorders, others could promote cognitive impairments, and our work highlights a lack of literature on this subject. In conclusion, more comparative clinical trials are needed to better understand the cognitive impact of addictolytic medications.

Alcohol addiction - the safety of available approved treatment options

INTRODUCTION

Alcohol Use Disorders (AUD) is a leading cause of mortality and morbidity worldwide. At present disulfiram, naltrexone and acamprosate are approved for the treatment of AUD in U.S. and Europe. Nalmefene is approved in Europe and sodium oxybate is approved in Italy and Austria only. Baclofen received a 'temporary recommendation for use' in France.

AREAS COVERED

The safety of the above mentioned medications on liver, digestive system, kidney function, nervous system, pregnancy and lactation and their possible side effects are described and discussed.

EXPERT OPINION

Mechanism of action and metabolism of these drugs as well as patients' clinical characteristics can affect the safety of treatment. All approved medications are valid tools for the treatment of AUD in patients without advanced liver disease. For some drugs, attention should be paid to patients with renal failure and medications may be used with caution, adjusting the dosage according to kidney function. In patients with AUD and advanced liver disease, at present only baclofen has been formally tested in randomized controlled trials showing its safety in this population.

Substance abuse/dependence treatment: a European perspective

During the past decade, substantial progress has been made in the field of addiction medicine in Europe, particularly regarding the development of new treatment interventions, resulting in a wide range of therapeutic options for patients with substance use disorders. However, not all interventions are evidence based. Patients with cannabis and cocaine/amphetamine use disorders and special patient populations especially lack evidence-based treatment recommendations. Many patients undergo treatment that has not been scientifically evaluated for quality and efficacy. Moreover, there are large disparities regarding availability and treatment access across Europe, with the new member states of the European Union (EU) reporting long waiting lists and low treatment coverage. Even in Austria, which ranks among the countries with relatively high treatment coverage and good diversification of treatment in opioid maintenance therapy due to the availability of methadone, buprenorphine, and slow-release oral morphine (SROM), a considerable population of untreated or inadequately treated patients exists. Treatment for substance use disorders in Europe still has scope for improvement in terms of treatment availability and access, which is ideally provided by further development and implementation of evidence-based interventions.

Efficacy and safety of the glycine transporter-1 inhibitor org 25935 for the prevention of relapse in alcohol-dependent patients: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Org 25935 is a glycine transporter inhibitor that increases extracellular glycine levels and attenuates alcohol-induced dopaminergic activity in the nucleus accumbens. In animal models, Org 25935 has dose-dependent effects on ethanol intake, preference, and relapse-like behavior without tolerance. The current study aimed to translate these animal findings to humans by examining whether Org 25935 prevents relapse in detoxified alcohol-dependent patients.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled clinical trial. Adult patients diagnosed with alcohol dependence were randomly assigned to receive Org 25935 12 mg twice a day or placebo for 84 days. The primary end point was percentage heavy drinking days (defined as ≥ 5 standard drinks per day for men and ≥ 4 for women). Secondary end points included other measures of relapse-related drinking behavior (e.g., drinks per day, time to relapse), as well as measures of global functioning, alcohol-related thoughts and cravings, and motivation.

RESULTS

A total of 140 subjects were included in the intent-to-treat analysis. The trial was stopped approximately midway after a futility analysis showing that the likelihood of detecting a signal at study term was <40%. There was no significant difference between Org 25935 and placebo on percentage heavy drinking days or any other measure of relapse-related drinking behavior. Org 25935 showed no safety issues and was fairly well tolerated, with fatigue, dizziness, and transient visual events as the most commonly occurring side effects.

CONCLUSIONS

Org 25935 demonstrated no benefit over placebo in preventing alcohol relapse. Study limitations and implications are discussed.

Long-term drug treatment of patients with alcohol dependence

Drug therapy for alcohol dependence should only be used in conjunction with a comprehensive treatment plan. Naltrexone and acamprosate have well established efficacy and are first-line treatments. Naltrexone is recommended for patients aiming to cut down their alcohol intake who do not have severe liver disease or an ongoing need for opioids. Acamprosate is recommended for those who have achieved and wish to maintain abstinence. Disulfiram is no longer considered first-line treatment due to difficulties with compliance and toxicity. Although baclofen and topiramate have evidence of benefit, they are not registered for alcohol dependence and should only be considered in specialist practice.

Regulator of G protein signaling 6 is a critical mediator of both reward-related behavioral and pathological responses to alcohol

Alcohol is the most commonly abused drug worldwide, and chronic alcohol consumption is a major etiological factor in the development of multiple pathological sequelae, including alcoholic cardiomyopathy and hepatic cirrhosis. Here, we identify regulator of G protein signaling 6 (RGS6) as a critical regulator of both alcohol-seeking behaviors and the associated cardiac and hepatic morbidities through two mechanistically divergent signaling actions. RGS6(-/-) mice consume less alcohol when given free access and are less susceptible to alcohol-induced reward and withdrawal. Antagonism of GABA(B) receptors or dopamine D2 receptors partially reversed the reduction in alcohol consumption in RGS6(-/-) animals. Strikingly, dopamine transporter inhibition completely restored alcohol seeking in mice lacking RGS6. RGS6 deficiency was associated with alterations in the expression of genes controlling dopamine (DA) homeostasis and a reduction in DA levels in the striatum. Taken together, these data implicate RGS6 as an essential regulator of DA bioavailability. RGS6 deficiency also provided dramatic protection against cardiac hypertrophy and fibrosis, hepatic steatosis, and gastrointestinal barrier dysfunction and endotoxemia when mice were forced to consume alcohol. Although RGS proteins canonically function as G-protein regulators, RGS6-dependent, alcohol-mediated toxicity in the heart, liver, and gastrointestinal tract involves the ability of RGS6 to promote reactive oxygen species-dependent apoptosis, an action independent of its G-protein regulatory capacity. We propose that inhibition of RGS6 might represent a viable means to reduce alcohol cravings and withdrawal in human patients, while simultaneously protecting the heart and liver from further damage upon relapse.

Transcranial Magnetic Stimulation and Deep Brain Stimulation in the treatment of alcohol dependence

Alcohol dependence is a major social, economic, and public health problem. Alcoholism can lead to damage of the gastrointestinal, nervous, cardiovascular, and respiratory systems and it can be lethal, costing hundreds of billions to the health care system. Despite the existence of cognitive-behavioral therapy, psychosocial interventions, and spiritually integrated treatment to treat it, alcohol dependence has a high relapse rate and poor prognosis, albeit with high interindividual variability. In this review, we discuss the use of two neuromodulation techniques, namely repetitive transcranial magnetic stimulation (rTMS) and deep brain stimulation (DBS), and their advantages and disadvantages compared to first-line pharmacological treatment for alcohol dependence. We also discuss rTMS and DBS targets for alcohol dependence treatment, considering experimental animal and human evidence, with careful consideration of methodological issues preventing the identification of feasible targets for neuromodulation treatments, as well as inter-individual variability factors influencing alcoholism prognosis. Lastly, we anticipate future research aiming to tailor the treatment to each individual patient by combining neurofunctional, neuroanatomical and neurodisruptive techniques optimizing the outcome.

The development of acamprosate as a treatment against alcohol relapse

INTRODUCTION

Globally, alcohol abuse and dependence are significant contributors to chronic disease and injury and are responsible for nearly 4% of all deaths annually. Acamprosate (Campral), one of only three pharmacological treatments approved for the treatment of alcohol dependence, has shown mixed efficacy in clinical trials in maintaining abstinence of detoxified alcoholics since studies began in the 1980s. Yielding inconsistent results, these studies have prompted skepticism.

AREAS COVERED

Herein, the authors review the preclinical studies which have assessed the efficacy of acamprosate in various animal models of alcohol dependence and discuss the disparate findings from the major clinical trials. Moreover, the authors discuss the major limitations of these preclinical and clinical studies and offer explanations for the often-contradictory findings. The article also looks at the importance of the calcium moiety that accompanies the salt form of acamprosate and its relevance to its activity.

EXPERT OPINION

The recent discovery that large doses of calcium largely duplicate the effects of acamprosate in animal models has introduced a serious challenge to the widely held functional association between this drug and the glutamate neurotransmission system. Future research on acamprosate or newer pharmacotherapeutics should consider assessing plasma and/or brain levels of calcium as a correlate or mediating factor in anti-relapse efficacy. Further, preclinical research on acamprosate has thus far lacked animal models of chemical dependence on alcohol, and the testing of rodents with histories of alcohol intoxication and withdrawal is suggested.

The clinical pharmacology of acamprosate

Acamprosate is one of the few medications licensed for prevention of relapse in alcohol dependence, and over time it has proved to be significantly, if moderately, effective, safe and tolerable. Its use is now being extended into other addictions and neurodevelopmental disorders. The mechanism of action of acamprosate has been less clear, but in the decade or more that has elapsed since its licensing, a body of translational evidence has accumulated, in which preclinical findings are replicated in clinical populations. Acamprosate modulates N-methyl-d-aspartic acid receptor transmission and may have indirect effects on γ-aminobutyric acid type A receptor transmission. It is known to decrease brain glutamate and increase β-endorphins in rodents and man. Acamprosate diminishes reinstatement in ethanolized rodents and promotes abstinence in humans. Although acamprosate has been called an anticraving drug, its subjective effects are subtle and relate to diminished arousal, anxiety and insomnia, which parallel preclinical findings of decreased withdrawal symptoms in animals treated with acamprosate. Further understanding of the pharmacology of acamprosate will allow appropriate targeting of therapy in individuals with alcohol dependence and extension of its use to other addictions.

Pharmacological means of reducing human drug dependence: a selective and narrative review of the clinical literature

Substance abuse or addictive disorder is a global problem. A greater understanding of the associated changes in brain pathophysiology supports the notion that pharmacological treatments are part of the necessary treatment options. Craving is a core symptom of addictive disorder. It refers to a strong desire to use drugs again either to re-experience positive effects or to diminish negative experiences. Currently there are a number of medicines that are effective in the treatment of addictive disorders. These medications can either be for substitution (same pharmacological effect as the abused substance) or anticraving (decrease the craving of the abused substance). In this MEDLNE based review, specific compounds (naltrexone, acamprosate, topiramate, disulfiram, baclofen, N-acetylcysteine and bupropion) were selected that are known to diminish desire to use (anticraving effect) and that have been trialled for a number of different substance addictive disorders. Their therapeutic potential in clinical practice is discussed in light of their efficacy.

Pharmacological strategies for detoxification

Detoxification refers to the safe discontinuation from a substance of dependence and is distinct from relapse prevention. Detoxification usually takes between a few days and a few weeks to complete, depending on the substance being misused, the severity of dependence and the support available to the user. Psychosocial therapies alongside pharmacological treatments are essential to improve outcome. The dependencies considered in this overview are detoxification from opioids (with methadone, buprenorphine, α2-adrenoceptor agonists and adjunct medications), alcohol (with benzodiazepines, anti-glutamatergics and γ-aminobutyric acid (GABA)-ergic drugs), stimulants and cannabis (with no clear recommended pharmacological treatments), benzodiazepines (with dose tapering) and nicotine (with nicotine replacement therapy, antidepressants and partial agonists). Evidence is limited by a lack of controlled trials robust enough for review bodies, and more research is required into optimal treatment doses and regimes, alone and in combination.

Treating the "unhealthy alcohol user" on medical wards: beyond withdrawal

BACKGROUND

Alcohol use disorders (AUDs) are common among patients admitted to general hospitals. Unfortunately, AUDs often go undetected and untreated. Psychiatrists are frequently called upon to assist in the management of cases involving alcohol withdrawal. However, there is a dearth of knowledge regarding potential therapeutic approaches to AUDs beyond the acute withdrawal stage.

OBJECTIVE

This article presents an overview of the epidemiology, clinical characteristics, and treatment of AUDs on medical wards, with a specific focus on the post alcohol-withdrawal phase.

METHOD

This article is based on a survey of the published literature on AUDs and their treatment in the medical ward using the PubMed database.

RESULTS

Various screening tools are available to facilitate the detection of AUDs. Among non-medically ill patients, brief psychological interventions have proven to be effective in primary care and emergency room settings, while pharmacotherapy has been shown to reduce the risk of relapse. Existing data on the implementation of these interventions in the general hospital setting remain scarce.

CONCLUSION

Current evidence suggests the need for additional research in this area with a view toward clarifying AUD treatment guidelines for medically ill inpatients. The hospital stay could provide a valuable opportunity to initiate interventions for AUDs with medically ill patients, leading to significant changes in alcohol use behaviors and better health-related outcomes.

Predictability of alcohol relapse by hippocampal volumetry and psychometric variables

We examined the relationship between relapse risk/duration of abstinence and hippocampal volume as well as the moderating role of various psychological factors in 34 patients who fulfilled the diagnostic criteria for alcohol dependence according to ICD-10 and DSM-IV and 16 healthy controls (9 females and 7 males). This study is part of a single-blind, placebo-controlled, parallel-group treatment trial with the anticraving substance acamprosate administered for 3 months. Patients underwent a psychometric evaluation and a measurement of the hippocampus with magnetic resonance imaging before beginning medication (T0). At 2, 4, 8, and 12 weeks after treatment, abstinence was evaluated by phone. Afterwards all patients switched to a long-term open label study with acamprosate. Hippocampal volume did not constitute a predictive factor for relapse probability in abstinent alcoholics. Furthermore, stress level, depressivity, gender, and treatment with the anticraving substance acamprosate did not show a significant correlation with relapse probability. The current investigation could not identify significant risk factors for relapses after successful alcohol withdrawal. Further studies are required to identify crucial factors which are responsible for successful or unsuccessful relapse prevention.

Management of alcohol dependence in patients with liver disease

Alcohol dependence represents a chronic and relapsing disease affecting nearly 10 % of the general population both in the USA and in Europe, with a widespread burden of morbidity and mortality. Alcohol dependence represents the most common cause of liver damage in the Western world. Although alcoholic liver disease is associated primarily with heavy drinking, continued alcohol consumption, even in low doses after the onset of liver disease, increases the risk of severe consequences, including mortality. Consequently, the ideal treatment of patients affected by alcohol dependence and alcoholic liver disease should aim at achieving long-term total alcohol abstinence and preventing relapse. The aim of the present review is to provide an update on the management of alcohol dependence in patients with alcoholic liver disease. Increasing evidence suggests the usefulness of psychosocial interventions and medications combined in order to reduce alcohol intake, promote abstinence and prevent relapse in alcohol-dependent patients. Disulfiram, naltrexone and acamprosate have been approved for this indication; gamma-hydroxybutyric acid (GHB) is approved in Italy and Austria. However, these drugs have not been tested in patients with advanced liver disease. Amongst other emerging pharmacotherapies for alcoholism, topiramate, ondansetron, and baclofen seem the most promising ones. Both topiramate and ondansetron have a safe profile in alcoholic patients; however, none of them has been tested in alcoholic patients with advanced liver disease. To date, baclofen represents the only anti-craving medication formally tested in a randomized clinical trial in alcoholic patients affected by liver cirrhosis, although additional confirmatory studies are warranted.

NMDA Receptor Modulators in the Treatment of Drug Addiction

Glutamate plays a pivotal role in drug addiction, and the N-methyl-d-aspartate (NMDA) glutamate receptor subtype serves as a molecular target for several drugs of abuse. In this review, we will provide an overview of NMDA receptor structure and function, followed by a review of the mechanism of action, clinical efficacy, and side effect profile of NMDA receptor ligands that are currently in use or being explored for the treatment of drug addiction. These ligands include the NMDA receptor modulators memantine and acamprosate, as well as the partial NMDA agonist d-Cycloserine. Data collected to date suggest that direct NMDA receptor modulators have relatively limited efficacy in the treatment of drug addiction, and that partial agonism of NMDA receptors may have some efficacy with regards to extinction learning during cue exposure therapy. However, the lack of consistency in results to date clearly indicates that additional studies are needed, as are studies examining novel ligands with indirect mechanisms for altering NMDA receptor function.

Safety and efficacy of acamprosate for the treatment of alcohol dependence

Acamprosate (calcium acetylhomotaurine) is an amino acid modulator that has displayed efficacy in some clinical trials in reducing craving and promoting abstinence in alcohol dependent patients following detoxification. While acamprosate is safe and generally well-tolerated, not all studies have demonstrated clinical efficacy that is superior to placebo. In addition, the precise neurochemical mechanisms of action of acamprosate have still not yet been identified. In this review, we summarize current clinical data on the safety, efficacy, and pharmacokinetic properties of acamprosate, as well theories on its potential mechanism of action. We also discuss tolerability and patient preference issues and conclude with a discussion of the place of acamprosate in addiction medicine and therapy.

Aldehyde dehydrogenase inhibitors: a comprehensive review of the pharmacology, mechanism of action, substrate specificity, and clinical application

Aldehyde dehydrogenases (ALDHs) belong to a superfamily of enzymes that play a key role in the metabolism of aldehydes of both endogenous and exogenous derivation. The human ALDH superfamily comprises 19 isozymes that possess important physiological and toxicological functions. The ALDH1A subfamily plays a pivotal role in embryogenesis and development by mediating retinoic acid signaling. ALDH2, as a key enzyme that oxidizes acetaldehyde, is crucial for alcohol metabolism. ALDH1A1 and ALDH3A1 are lens and corneal crystallins, which are essential elements of the cellular defense mechanism against ultraviolet radiation-induced damage in ocular tissues. Many ALDH isozymes are important in oxidizing reactive aldehydes derived from lipid peroxidation and thereby help maintain cellular homeostasis. Increased expression and activity of ALDH isozymes have been reported in various human cancers and are associated with cancer relapse. As a direct consequence of their significant physiological and toxicological roles, inhibitors of the ALDH enzymes have been developed to treat human diseases. This review summarizes known ALDH inhibitors, their mechanisms of action, isozyme selectivity, potency, and clinical uses. The purpose of this review is to 1) establish the current status of pharmacological inhibition of the ALDHs, 2) provide a rationale for the continued development of ALDH isozyme-selective inhibitors, and 3) identify the challenges and potential therapeutic rewards associated with the creation of such agents.

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

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

Adenosinergic system: an assorted approach to therapeutics for drug addiction

Adenosine is an endogenous purine nucleoside and it is extensively present in the brain. It exerts several metabolic and neuromodulatory roles in the body. Adenosine also acts as an important messenger molecule for extracellular signaling and shows a homeostatic neuromodulatory function at the synaptic level. Extracellular adenosine exerts a wide variety of biological actions through four cell surface G-protein-coupled receptor subtypes, namely A1, A2A, A2B and A3 adenosine receptors. The extracellular levels of adenosine have been found to be enhanced in several neuropathological conditions, including drug addiction, and thus a neuroprotective role of adenosine was perceived by various experimental studies. The aversive withdrawal symptoms emanating from drug discontinuation provokes rebound drug intake patterns. In addition, alteration of neurotransmitter(s) release and changes in receptor expression contribute to the behavioral changes of drug withdrawal. Furthermore, the abuse of major drugs such as alcohol and opioids are reported to modulate extracellular adenosine levels. In this context, the neuromodulatory functions of adenosine would be valuable if projected to the clinical applications and thus, an increasing attention is currently given to the functional role of adenosine in human addictive disorders. This review will focus on recent clinical and experimental studies that reveal the actions of adenosine and related ligands in drug addiction and various drug-withdrawal syndromes. The evidence and reports provided in this review highlight the looming therapeutic potential of purinergic drugs, with a hope that new therapeutic interventions based on the adenosinergic concept will emerge in the coming years for the management of drug withdrawal syndrome.

Acamprosate for treatment of alcohol dependence: mechanisms, efficacy, and clinical utility

Acamprosate, or N-acetyl homotaurine, is an N-methyl-D-aspartate receptor modulator approved by the Food and Drug Administration (FDA) as a pharmacological treatment for alcohol dependence. The exact mechanism of action of acamprosate is still under investigation, but the drug appears to work by promoting a balance between the excitatory and inhibitory neurotransmitters, glutamate and gamma-aminobutyric acid, respectively, and it may help individuals with alcohol dependence by reducing withdrawal-associated distress. Acamprosate has low bioavailability, but also has an excellent tolerability and safety profile. In comparison with naltrexone and disulfiram, which are the other FDA-approved treatments for alcohol dependence, acamprosate is unique in that it is not metabolized by the liver and is also not impacted by alcohol use, so can be administered to patients with hepatitis or liver disease (a common comorbid condition among individuals with alcohol dependence) and to patients who continue drinking alcohol. Acamprosate has demonstrated its efficacy in more than 25 placebo-controlled, double-blind trials for individuals with alcohol dependence, and has generally been found to be more efficacious than placebo in significantly reducing the risk of returning to any drinking and increasing the cumulative duration of abstinence. However, acamprosate appears to be no more efficacious than placebo in reducing heavy drinking days. Numerous trials have found that acamprosate is not significantly more efficacious than naltrexone or disulfiram, and the efficacy of acamprosate does not appear to be improved by combining acamprosate with other active medications (eg, naltrexone) or with psychosocial treatment (eg, cognitive-behavioral therapy). In this review, we present the data on acamprosate, including its pharmacology, efficacy, safety, and tolerability in the treatment of alcohol dependence.

The mGluR5 antagonist MPEP elevates accumbal dopamine and glycine levels; interaction with strychnine-sensitive glycine receptors

Studies have indicated that the metabotropic glutamate receptor 5 (mGluR5) antagonist 6-methyl-2-(phenylethynyl)-pyridine (MPEP) decreases ethanol self-administration, and the same receptor type was also suggested to be involved in the mechanism of action of the anti-craving substance acamprosate. Our previous research suggested that glycine receptors (GlyRs) in the nucleus accumbens (nAc) play a major part in mediating the dopamine-elevating properties of ethanol and are highly involved in the ethanol intake-reducing effect of acamprosate. The aim of this study was to examine if modulation of nAc dopamine via mGluR5 antagonism or GlyR agonism is a linked or separated phenomena. The extracellular levels of dopamine as well as of the GlyR ligands, glycine, taurine and β-alanine were measured in the nAc by means of microdialysis after local perfusion of MPEP (100 or 500 µM) with or without pre-treatment with strychnine. MPEP increased dopamine levels, an effect that was blocked by pre-treatment with strychnine. In addition, the higher MPEP concentration increased glycine output, whereas no alterations of taurine or β-alanine were observed. These results indicate a relationship between the glutamatergic and glycinergic transmitter systems in regulating dopamine output, possibly via alteration of extracellular glycine levels. Taken together with our previous data demonstrating the importance of accumbal GlyRs both in ethanol-induced elevation of nAc dopamine and in ethanol consumption, it is plausible that the effects of MPEP treatment, on dopamine output and on ethanol intake, may be mediated via interaction with the same neuronal circuitry that previously has been demonstrated for ethanol, taurine and acamprosate.

Effects of acamprosate on cognition in a treatment study of patients with schizophrenia spectrum disorders and comorbid alcohol dependence

Problems with memory and attention are common to both schizophrenia and alcohol dependence. The objectives of this study were to examine the effect of acamprosate treatment on cognition and to assess whether the changes in drinking patterns or psychotic symptoms were related to changes in cognitive functioning. Outpatients with schizophrenia spectrum disorders and alcohol dependence (n = 23) were randomized (double-blind) to either acamprosate or placebo treatment for 12 weeks. Assessments (baseline and week 12) included alcohol use, symptoms of psychosis, memory, and attention. The results showed that acamprosate had no effect on cognitive functioning and that there was no relationship between change in alcohol consumption or psychotic symptoms and change in cognitive functioning in this sample of patients. The finding that acamprosate had no negative effects on cognition is clinically relevant and reinforces previous reports that acamprosate can be used safely for alcohol reduction in this group of patients.

Glutamatergic medications for the treatment of drug and behavioral addictions

Historically, most pharmacological approaches to the treatment of addictive disorders have utilized either substitution-based methods (i.e., nicotine replacement or opioid maintenance) or have targeted monoaminergic or endogenous opioidergic neurotransmitter systems. However, substantial evidence has accumulated indicating that ligands acting on glutamatergic transmission are also of potential utility in the treatment of drug addiction, as well as various behavioral addictions such as pathological gambling. The purpose of this review is to summarize the pharmacological mechanisms of action and general clinical efficacy of glutamatergic medications that are currently approved or are being investigated for approval for the treatment of addictive disorders. Medications with effects on glutamatergic transmission that will be discussed include acamprosate, N-acetylcysteine, d-cycloserine, gabapentin, lamotrigine, memantine, modafinil, and topiramate. We conclude that manipulation of glutamatergic neurotransmission is a relatively young but promising avenue for the development of improved therapeutic agents for the treatment of drug and behavioral addictions.

Neuroscience of behavioral and pharmacological treatments for addictions

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

Treatment With Acamprosate in Patients With Schizophrenia Spectrum Disorders and Comorbid Alcohol Dependence

OBJECTIVE

Alcohol use disorders and schizophrenia frequently co-occur with rates higher than in the general population. There is no consensus on the best treatment for patients with these comorbid conditions. Several clinical trials have shown that acamprosate is superior to placebo in reducing drinking and is particularly effective in sustaining abstinence. No study to date has examined the efficacy of acamprosate in patients with alcohol dependence and comorbid schizophrenia. The aims of this study are to assess the efficacy of acamprosate when compared to placebo in reducing drinking and to examine its effects on schizophrenic symptoms.

METHODS

This was a double-blind, randomized, 12-week treatment trial of acamprosate versus placebo. Twenty-three recently abstinent patients with diagnosed alcohol dependence and comorbid schizophrenia, schizoaffective disorder, or psychosis not otherwise specified were included in this study.

RESULTS

All participants significantly decreased their drinking during medication treatment, although acamprosate was not superior to placebo in increasing consecutive days of abstinence. There was a significant difference favoring the acamprosate group on obsessive thoughts of drinking but no significant group X time interaction. Overall, medication treatment significantly reduced positive symptoms of schizophrenia, but there were no group differences.

CONCLUSIONS

Acamprosate was not more effective than placebo in reducing drinking or symptoms of schizophrenia. It can be safely used in patients with alcohol dependence and comorbid schizophrenia spectrum disorders.