Acamprosate in the treatment of alcohol dependence

Reward and relief dimensions of temptation to drink: construct validity and role in predicting differential benefit from acamprosate and naltrexone

Researchers have sought to distinguish between individuals whose alcohol use disorder (AUD) is maintained by drinking to relieve negative affect ('relief drinkers') and those whose AUD is maintained by the rewarding effects of alcohol ('reward drinkers'). As an opioid receptor antagonist, naltrexone may be particularly effective for reward drinkers. Acamprosate, which has been shown to down-regulate the glutamatergic system, may be particularly effective for relief drinkers. This study sought to replicate and extend prior work (PREDICT study; Glöckner-Rist et al. ) by examining dimensions of reward and relief temptation to drink and subtypes of individuals with distinct patterns of reward/relief temptation. We utilized data from two randomized clinical trials for AUD (Project MATCH, n = 1726 and COMBINE study, n = 1383). We also tested whether classes of reward/relief temptation would predict differential response to naltrexone and acamprosate in COMBINE. Results replicated prior work by identifying reward and relief temptation factors, which had excellent reliability and construct validity. Using factor mixture modeling, we identified five distinct classes of reward/relief temptation that replicated across studies. In COMBINE, we found a significant class-by-acamprosate interaction effect. Among those most likely classified in the high relief/moderate reward temptation class, individuals had better drinking outcomes if assigned to acamprosate versus placebo. We did not find a significant class-by-naltrexone interaction effect. Our study questions the orthogonal classification of drinkers into only two types (reward or relief drinkers) and adds to the body of research on moderators of acamprosate, which may inform clinical decision making in the treatment of AUD.

Emerging concepts in alcoholic hepatitis

Severe alcoholic hepatitis is implicated as a costly, worldwide public health issue with high morbidity and mortality. The one-month survival for severe alcoholic hepatitis is low with mortality rates high as 30%-50%. Abstinence from alcohol is the recommended first-line treatment. Although corticosteroids remain as the current evidence based option for selected patients with discriminant function > 32, improvement of short-term survival rate may be the only benefit. Identification of individuals with risk factors for the development of severe alcoholic hepatitis may provide insight to the diverse clinical spectrum and prognosis of the disease. The understanding of the complex pathophysiologic processes of alcoholic hepatitis is the key to elucidating new therapeutic treatments. Newer research describes the use of gut microbiota modification, immune modulation, stimulation of liver regeneration, caspase inhibitors, farnesoid X receptors, and the extracorporeal liver assist device to aid in hepatocellular recovery. Liver transplantation can be considered as the last medical option for patients failing conventional medical interventions. Although the preliminary data is promising in patients with low risk of recividism, controversy remains due to organ scarcity. This review article comprehensively summarizes the epidemiology, pathophysiology, risk factors, and prognostic indicators of severe alcoholic hepatitis with a focus on the current and emerging therapeutics.

A Phase 2, Double-Blind, Placebo-Controlled Randomized Trial Assessing the Efficacy of ABT-436, a Novel V1b Receptor Antagonist, for Alcohol Dependence

Alcohol use disorder has been linked to dysregulation of the brain stress systems, producing a negative emotional state leading to chronic relapsing behavior. Vasopressin receptors appear to have a regulatory role in stress, anxiety, and alcohol. This study evaluated the novel compound, ABT-436, a V1b receptor antagonist, in alcohol-dependent participants in a 12-week clinical trial. Men and women (n=150) who met criteria for DSM-IV alcohol dependence were recruited across four sites. Participants received double-blind ABT-436 or placebo, and a computerized behavioral intervention. ABT-436 was titrated to 800 mg/day during weeks 2-12. Although the primary outcome, percentage of heavy drinking days, was lower in participants receiving ABT-436 compared with placebo, this difference was not statistically significant (31.3 vs 37.6, respectively; p=0.172; d=0.20). However, participants receiving ABT-436 had significantly greater percentage of days abstinent than those receiving placebo (51.2 vs 41.6, respectively; p=0.037; d=0.31). No significant differences were found between treatment groups on any other measures of drinking, alcohol craving, or alcohol-related consequences. Smokers receiving ABT-436 smoked significantly fewer cigarettes per week than those receiving placebo (p=0.046). ABT-436 was well tolerated, with diarrhea (mild-to-moderate severity) being the most common side effect. In subgroup analyses, participants with relatively higher baseline levels of stress responded better to ABT-436 than placebo on select drinking outcomes, suggesting there may be value in testing medications targeting the vasopressin receptor in high stress, alcohol-dependent patients.

New paradigms in management of alcoholic hepatitis: a review

Severe alcoholic hepatitis (SAH) is defined by modified Maddrey discriminant function ≥32 or Model for End-Stage Liver Disease (MELD) >21 and/or hepatic encephalopathy. It has a 3-month mortality rate ≥30-70 %. Patients with severe alcoholic hepatitis need combined, i.e., static (MELD score) and dynamic (Lille's score), prognostication. Systemic inflammation and poor regeneration are hallmarks of SAH, rather than intrahepatic inflammation. SAH is characterized by dysregulated and uncontrolled systemic inflammatory response followed by weak compensatory antiinflammatory response that leads to increased susceptibility to infection and multiple organ failure. Massive necrosis of hepatocytes exceeds the proliferative capacity of hepatocytes. Liver progenitor cells proliferate to form narrow ductules which radiate out into the damaged liver parenchyma. Corticosteroids have been the standard-of-care therapy, albeit controversial. However, the recent Steroids or Pentoxifylline for Alcoholic Hepatitis (STOPAH) trial revealed that prednisolone was not associated with a significant reduction in 28-day mortality, with no improvement in outcomes at 90 days or 1 year. A paradigm shift from antiinflammatory therapy such as corticosteroids to liver regeneration treatment, e.g., granulocyte-colony stimulating factor, molecular targeted treatments, and fecal microbiota transplantation, for severe alcoholic hepatitis is taking place. Liver transplantation should be offered to select patients with severe alcoholic hepatitis who are nonresponsive to medical treatment.

Pharmacotherapy of alcoholic liver disease in clinical practice

AIMS

Alcohol is the most commonly used addictive substance and alcoholic liver disease (ALD) is a major cause of chronic liver disease worldwide, responsible for 47.9% of all liver chronic deaths. Despite ALD has a significant burden on the health, few therapeutic advances have been made in the last 40 years, particularly in the long-term management of these patients.

METHODS

we searched in PubMed, Scopus, Google Scholar, and MEDLINE databases to identify relevant English language publications focused on long-term therapy of ALD.

RESULTS

From the huge literature on this topic, including about 755 studies, 75 were selected as eligible including clinical trials and meta-analysis.

CONCLUSIONS

Abstinence remains the cornerstone of ALD therapy but it is also the most difficult therapeutic target to achieve and the risk of recidivism is very high at any time. Several drugs (disulfiram, naltrexone, acamprosate, sodium oxybate) have proven to be effective to prevent alcohol relapse and increase the abstinence, although the psychotherapeutic support remains crucial. Baclofen seems to be effective to improve abstinence, showing an excellent safety and tolerability. ALD is often complicated by a state of malnutrition, which is related to a worst mortality. A nutritional therapy may improve survival in cirrhotic patients, reversing muscle wasting, weight loss and specific nutritional deficiencies. While in aggressive forms of alcoholic hepatitis are recommended specific drug treatments, including glucocorticoids or pentoxifylline, for the long-term treatment of ALD, specific treatments aimed at stopping the progression of fibrosis are not yet approved, but there are some future perspective in this field, including probiotics and antibiotics, caspase inhibitors, osteopontin and endocannabinoids.

Prognosis and treatment of patients with acute alcoholic hepatitis

Despite alcoholic hepatitis (AH) is the most acute manifestation of alcohol-related liver disease, its treatment remains controversial. Corticosteroids, given either as monotherapy or together with N-acetylecysteine, have been associated with a moderate short-term survival benefit in patients with severe disease. The Maddrey's discriminant function; Glasgow alcoholic hepatitis score; age, bilirubin, INR and creatinine score; and the Model for end-stage liver disease have been proposed for stratifying prognosis in AH enabling selection of the patients to treat. Definition of treatment non-responders using the Lille model after 7 days of therapy may prevent a detrimental impact of prolonged corticosteroids. Pentoxifylline is an effective alternative reducing the occurrence of hepatorenal syndrome. Emerging evidence supports use of liver transplantation in a strictly selected subset of corticosteroid non-responders.

Management of alcoholic hepatitis: Current concepts

Alcoholic hepatitis is a devastating form of acute liver injury seen in chronic alcohol abusers with significant morbidity and mortality. It is a multisystem disease that is precipitated by ingesting large quantities of alcohol with genetic and environmental factors playing a role. Prognostic criteria have been developed to predict disease severity and these criteria can serve as indicators to initiate medical therapy. Primary therapy remains abstinence and supportive care, as continued alcohol abuse is the most important risk factor for disease progression. The cornerstone of supportive care remains aggressive nutritional support, and although acute alcoholic hepatitis has been extensively studied, few specific medical therapies have been successful. Corticosteroids remain the most effective medical therapy available in improving short term survival in a select group of patients with alcoholic hepatitis; however, the long-term outcome of drug therapies is still not entirely clear and further clinical investigation is necessary. While liver transplantation for acute alcoholic hepatitis have demonstrated promising results, this practice remains controversial and has not been advocated universally, with most transplant centers requiring a prolonged period of abstinence before considering transplantation. Extracorporeal liver support devices, although still experimental, have been developed as a form of liver support to give additional time for liver regeneration. These have the potential for a significant therapeutic option in the future for this unfortunately dreadful disease.

Meta-analyses of placebo-controlled trials of acamprosate for the treatment of alcohol dependence: impact of the combined pharmacotherapies and behavior interventions study

OBJECTIVES

: The Combined Pharmacotherapies and Behavior Interventions Study (COMBINE) reported no significant difference between acamprosate and placebo in the treatment of alcohol dependence. To evaluate the impact of COMBINE, we performed a meta-analysis of acamprosate placebo-controlled trials with the inclusion of data from COMBINE. As a secondary analysis, we added the COMBINE data to a recently published meta-analysis of naltrexone placebo-controlled trials.

METHODS

: A structured literature search of major databases was performed from January 1990 to August 2007 for acamprosate placebo-controlled randomized trials. Mean differences in cumulative abstinent days (CAD) and abstinence rates (AR) from eligible studies were statistically combined to calculate point estimates and 95% CI for differences in CAD and AR.

RESULTS

: Ten and 16 studies evaluating CAD and AR, respectively were suitable for statistical pooling. The findings revealed that acamprosate was superior to placebo in the mean number of CAD (P < 0.001) and AR (pooled AR = 1.58; P < 0.001). The pooled AR for naltrexone was also significant indicating a relative benefit over placebo (AR = 1.27; P < 0.001). The COMBINE trial results contributed a weight of less than 15% to the final pooled statistical outcomes for both agents.

CONCLUSIONS

: The current study confirmed that acamprosate and naltrexone are both effective agents for the treatment of patients with alcohol dependence. Systematic reviews with meta-analyses of randomized controlled trials and randomized controlled trials with adequate sample sizes are in the same (highest) level of evidence. Therefore, clinicians should use both these sources of information as their foundation for selecting optimal therapy for patients with alcohol dependence.

Acamprosate: safety and tolerability in the treatment of alcohol dependence

Acamprosate, in conjunction with psychosocial treatment, has demonstrated efficacy in maintaining abstinence in alcohol-dependent patients in multiple clinical trials. Data from 13 short-term (≤26 weeks) and long-term (≥48 weeks) clinical trials were analyzed to assess the safety and tolerability of acamprosate: 4234 patients were randomized to placebo (N = 1962), acamprosate 1332 mg/d (N = 440), 1998 mg/d (N = 1749), or 3000 mg/d (N = 83). Overall incidence of treatment-emergent adverse events (AEs) was 61% for acamprosate and 56% for placebo (P < 0.01). The majority of AEs in all groups were reported as transient and considered "mild" or "moderate" in severity, and discontinuation rates due to AEs were comparable. Most common AEs were diarrhea (16% acamprosate versus 10% placebo, P < 0.01) and flatulence (3% acamprosate versus 2% placebo, P < 0.01). Patients taking concomitant medications commonly used to treat alcohol dependence reported comparable AEs between placebo- and acamprosate-treated groups.Acamprosate was shown to be safe in patients with hepatic impairment. A dose reduction is recommended in patients with renal impairment. No clinically meaningful between-group differences were reported for clinical chemistry tests or vital sign parameters. This ad hoc analysis demonstrates that acamprosate can be used safely in alcohol-dependent patients, including those taking concomitant medications, or having renal or hepatic impairment.

Therapeutic drug monitoring for drugs used in the treatment of substance-related disorders: literature review using a therapeutic drug monitoring appropriateness rating scale

BACKGROUND

The efficacy of drugs for the treatment of substance-related disorders is moderate at best. Therapeutic drug monitoring (TDM) could be an instrument to improve outcomes. Because TDM for most of those drugs is not established, the authors reviewed the literature and built a rating scale to detect the potential added value of TDM for these pharmacologic agents.

METHODS

A literature search was performed for acamprosate, bupropion, buprenorphine, clomethiazole, disulfiram, methadone, naltrexone, and varenicline. The rating scale included 22 items and was divided in five categories: efficacy, toxicity, pharmacokinetics, patient characteristics, and cost-effectiveness. Three reference substances with established TDM were similarly assessed for comparison: clozapine, lithium, and nortriptyline. The three reference substances achieved scores of 15, 12, and 14 points, respectively.

RESULTS

Drugs for treatment of substance-related disorders achieved 3 to 17 points, 17 for methadone, 11 for buprenorphine, 10 for disulfiram, also 10 for naltrexone for the indication opioid-dependence and 9 for the indication alcohol dependence as well as bupropion, 7 points for acamprosate, 6 points for clomethiazole, and 3 for varenicline.

CONCLUSIONS

It is concluded that systematic evaluation of drug- and patient-related variables with the new rating scale can estimate the appropriateness of TDM. Because their rating revealed similar scores as the three reference drugs, it is proposed that TDM should be established for bupropion, buprenorphine, disulfiram or a metabolite, methadone, and naltrexone. An objective rating of drug- and patient-related characteristics could help laboratories focus their method development on the most likely drugs to require TDM along with a thorough drug use evaluation.

Neuronal nicotinic acetylcholine receptors as pharmacotherapeutic targets for the treatment of alcohol use disorders

Alcohol use disorders (AUDs) are complex, and developing effective treatments will require the combination of novel medications and cognitive behavioral therapy approaches. Epidemiological studies have shown there is a high correlation between alcohol consumption and tobacco use, and the prevalence of smoking in alcoholics is as high as 80% compared to about 30% for the general population. Both preclinical and clinical data provide evidence that nicotine administration increases alcohol intake and non-specific nicotinic receptor antagonists reduce alcohol-mediated behaviors. As nicotine interacts specifically with the neuronal nicotinic acetylcholine receptor (nAChR) system, this suggests that nAChRs play an important role in the behavioral effects of alcohol. In this review, we discuss the importance of nAChRs for the treatment of AUDs and argue that the use of FDA approved nAChR ligands, such as varenicline and mecamylamine, approved as smoking cessation aids may prove to be valuable treatments for AUDs. We also address the importance of combining effective medications with behavioral therapy for the treatment of alcohol dependent individuals.

Acamprosate

IMPORTANCE OF THE FIELD

Alcohol abuse and dependence are major causes of morbidity and mortality and come with a high societal cost. The illness is notoriously difficult to treat and relapse is a common occurrence. Acamprosate represents an effective addition to the treatment options available for alcohol dependence with a novel mechanism of action.

AREAS COVERED IN THIS REVIEW

We review the published acamprosate literature focusing on major and recent comparative clinical trials and meta-analyses. We included all studies found in National Library of Medicine's PubMed database searching on Mesh term: acamprosate excluded animal studies excluding non-English publications, and focusing on efficacy/effectiveness studies. Additionally, we discuss background information on alcohol dependence and acamprosate's putative mechanism of action. Safety and tolerability data are also presented.

WHAT THE READER WILL GAIN

The reader will gain a better understanding of the role of acamprosate in the treatment of alcohol dependence and find a useful synopsis of the more recently published literature evaluating acamprosate's effectiveness based on what are not always identically defined primary study outcomes.

TAKE HOME MESSAGE

Acamprosate is safe and effective in the maintenance of abstinence from alcohol use/abuse and is most commonly used in combination with nonpharmacologic therapeutic modalities. The effect size ranged from 1.3 to 2 for most of the studies included in this review.

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

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

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

IMPORTANCE TO THE FIELD

Acamprosate, marketed under the brand name Campral, (Forest Pharmaceuticals, Inc., Saint Louis, MO, USA; Merck Sante s.a.s., Lyon, France) is an orally administered drug approved in the US and throughout much of the world for treating alcohol dependence. Its safety and efficacy have been demonstrated in a number of clinical trials worldwide and as with all pharmacotherapies for alcoholism, it is used in conjunction with psychosocial interventions.

AREAS COVERED IN THIS REVIEW

This article reviews the mechanism of action, clinical efficacy and safety of acamprosate in Phase I, II and III randomized controlled trials involving healthy and alcohol-dependent populations using published reports from 1984 to 2009.

WHAT THE READER WILL GAIN

This review provides an update of the mechanism of action and the safety and efficacy profile of acamprosate.

TAKE HOME MESSAGE

Acamprosate appears to act centrally to restore the normal activity of glutamatergic neurotransmission altered by chronic alcohol exposure. Acamprosate's excellent safety profile along with several pharmacokinetic and pharmacodynamic characteristics make it well suited for treating a broad population of alcohol-dependent patients.

Alcoholic liver disease

These recommendations provide a data-supported approach. They are based on the following: (i) a formal review and analysis of the recently published world literature on the topic (Medline search); (ii) American College of Physicians Manual for Assessing Health Practices and Designing Practice Guidelines (1); (iii) guideline policies, including the American Association for the Study of Liver Diseases (AASLD) Policy on the development and use of practice guidelines and the AGA Policy Statement on Guidelines (2); and (iv) the experience of the authors in the specified topic. Intended for use by physicians, these recommendations suggest preferred approaches to the diagnostic, therapeutic, and preventive aspects of care. They are intended to be flexible, in contrast to the standards of care, which are inflexible policies to be followed in every case. Specific recommendations are based on relevant published information. To more fully characterize the quality of evidence supporting the recommendations, the Practice Guideline Committee of the AASLD requires a Class (reflecting the benefit vs. risk) and Level (assessing the strength or certainty) of Evidence to be assigned and reported with each recommendation (Table 1, adapted from the American College of Cardiology and the American Heart Association Practice Guidelines) (3,4).

The pharmacotherapy of alcohol dependence: a state of the art review

The psychopharmacology of alcohol dependence is today poised at interesting crossroads. Three major drugs Naltrexone, Disulfiram and Acamprosate have been tried and tested in various trials and have many meta-analyses each to support them. While Naltrexone may reduce craving, Acamprosate scores on cost effectiveness worldwide with Disulfiram being an alcohol deterrent drug. Studies support, refute and criticize the use of each of these drugs. Combining one or more of them is also a trend seen. The most important factor in efficacy has been the combination of psychosocial treatment with medication. Studies from the early 1970s to date have been reviewed and the findings presented in a manner useful for the busy clinician to judge the best pharmacological option in the management of alcohol dependence. The role of depot disulfiram, naltrexone, and medications like Topiramate and SSRIs under research for alcohol dependence, are also addressed.

Glycine receptors in the nucleus accumbens involved in the ethanol intake-reducing effect of acamprosate

BACKGROUND

We have previously demonstrated that strychnine-sensitive glycine receptors (GlyRs) in the nucleus accumbens (nAc) and nicotinic acetylcholine receptors (nAChRs) in the ventral tegmental area are involved in mediating ethanol (EtOH)-induced elevation of dopamine in the rat mesolimbic dopamine system. This neuronal circuitry was also demonstrated to mediate dopamine elevation in the nAc after both taurine, an endogenous agonist of GlyRs, and acamprosate, a synthetic derivate of homotaurine. The aim of this study was to investigate whether the EtOH intake-reducing effect of acamprosate involves accumbal GlyRs.

METHODS

For this purpose, we used a voluntary EtOH consumption model where EtOH medium- and high-preferring rats were implanted with guide cannulae in the nAc. The animals received daily injections of acamprosate or 0.9% NaCl before accessing a bottle of 6% EtOH and a bottle of water. After 2 days, a microinjection of strychnine or vehicle preceded the daily systemic injection and bottle-access period.

RESULTS

Acamprosate, but not saline, decreased EtOH intake. Pretreatment with Ringer in the nAc did not influence EtOH intake in saline or acamprosate-treated animals. Pretreatment with strychnine had no effect on EtOH intake in saline-treated animals, whereas it completely reversed the EtOH intake-reducing effect of acamprosate.

CONCLUSIONS

Based on current and previous results, we suggest that acamprosate primarily interacts with accumbal GlyRs and secondarily with ventral tegmental nAChRs, in a similar manner to that previously observed with EtOH and taurine. The interaction between acamprosate and GlyRs does not only influence dopamine output in the nAc but also EtOH consumption, giving further support for our hypothesis that GlyRs are of importance in EtOH reinforcement.

Understanding attitudes towards use of medication in substance abuse treatment: A multilevel approach

Individual and organizational variables influence attitudes towards use of naltrexone, methadone, and buprenorphine for the treatment of alcohol and drug disorders. Prior research has not considered both sets of influences simultaneously. Hierarchical linear modeling tested the contribution of individual and organizational variables using data from the National Drug Abuse Treatment Clinical Trials Network treatment unit and workforce surveys (n = 2,269 staff nested within 247 treatment units). Individual-level variables consistently had more influence on attitudes, but a unique blend of variables existed for each medication. One predictor, support for psychiatric medications, influenced attitudes across all medications. Staff attitudes towards addiction medications varied significantly between treatment units. Implications for increasing the appropriate use of addiction medications are discussed.

Exposure to the taste of alcohol elicits activation of the mesocorticolimbic neurocircuitry

A growing number of imaging studies suggest that alcohol cues, mainly visual, elicit activation in mesocorticolimbic structures. Such findings are consistent with the growing recognition that these structures play an important role in the attribution of incentive salience and the pathophysiology of addiction. The present study investigated whether the presentation of alcohol taste cues can activate brain regions putatively involved in the acquisition and expression of incentive salience. Using functional magnetic resonance imaging, we recorded BOLD activity while delivering alcoholic tastes to 37 heavy drinking but otherwise healthy volunteers. The results yielded a pattern of BOLD activity in mesocorticolimbic structures (ie prefrontal cortex, striatum, ventral tegmental area/substantia nigra) relative to an appetitive control. Further analyses suggested strong connectivity between these structures during cue-elicited urge and demonstrated significant positive correlations with a measure of alcohol use problems (ie the Alcohol Use Disorders Identification Test). Thus, repeated exposure to the taste alcohol in the scanner elicits activation in mesocorticolimbic structures, and this activation is related to measures of urge and severity of alcohol problems.

Homers regulate drug-induced neuroplasticity: implications for addiction

Drug addiction is a chronic, relapsing disorder, characterized by an uncontrollable motivation to seek and use drugs. Converging clinical and preclinical observations implicate pathologies within the corticolimbic glutamate system in the genetic predisposition to, and the development of, an addicted phenotype. Such observations pose cellular factors regulating glutamate transmission as likely molecular candidates in the etiology of addiction. Members of the Homer family of proteins regulate signal transduction through, and the trafficking of, glutamate receptors, as well as maintain and regulate extracellular glutamate levels in corticolimbic brain regions. This review summarizes the existing data implicating the Homer family of protein in acute behavioral and neurochemical sensitivity to drugs of abuse, the development of drug-induced neuroplasticity, as well as other behavioral and cognitive pathologies associated with an addicted state.

Glutamatergic substrates of drug addiction and alcoholism

The past two decades have witnessed a dramatic accumulation of evidence indicating that the excitatory amino acid glutamate plays an important role in drug addiction and alcoholism. The purpose of this review is to summarize findings on glutamatergic substrates of addiction, surveying data from both human and animal studies. The effects of various drugs of abuse on glutamatergic neurotransmission are discussed, as are the effects of pharmacological or genetic manipulation of various components of glutamate transmission on drug reinforcement, conditioned reward, extinction, and relapse-like behavior. In addition, glutamatergic agents that are currently in use or are undergoing testing in clinical trials for the treatment of addiction are discussed, including acamprosate, N-acetylcysteine, modafinil, topiramate, lamotrigine, gabapentin and memantine. All drugs of abuse appear to modulate glutamatergic transmission, albeit by different mechanisms, and this modulation of glutamate transmission is believed to result in long-lasting neuroplastic changes in the brain that may contribute to the perseveration of drug-seeking behavior and drug-associated memories. In general, attenuation of glutamatergic transmission reduces drug reward, reinforcement, and relapse-like behavior. On the other hand, potentiation of glutamatergic transmission appears to facilitate the extinction of drug-seeking behavior. However, attempts at identifying genetic polymorphisms in components of glutamate transmission in humans have yielded only a limited number of candidate genes that may serve as risk factors for the development of addiction. Nonetheless, manipulation of glutamatergic neurotransmission appears to be a promising avenue of research in developing improved therapeutic agents for the treatment of drug addiction and alcoholism.

The treatment of alcohol dependence

PURPOSE OF REVIEW

The present review summarizes current research on the management of alcohol dependence, including pharmacotherapy, psychosocial interventions and treatment of alcohol dependence with comorbid psychiatric disorders.

RECENT FINDINGS

Among recent studies, naltrexone has demonstrated the most consistent effect in reducing alcohol consumption in the context of behavioral therapy. In contrast to most previous studies, acamprosate did not show significant benefits on treatment outcomes relative to placebo. The combined use of naltrexone and acamprosate appeared to be safe and well tolerated but there was no additional therapeutic benefit. With the exception of topiramate, there are currently no new, effective medications for alcohol dependence. Of the psychosocial interventions, such as social behavior and network therapy, cognitive behavioral therapy, and motivational enhancement therapy, no one appears to be superior to another. Psychiatric comorbidity is common in alcohol-dependent patients; however, there are too few studies to effectively guide treatment practice.

SUMMARY

Progress has been made with pharmacotherapy and psychosocial interventions for alcohol-dependent individuals. More research is needed, however, in developing newer medications and psychosocial interventions in alcohol-dependent populations and in those with comorbid psychiatric conditions, and to improve the strategies to engage patients in continuing care.

Sustained-release naltrexone formulations for the treatment of alcohol and opioid dependence

Naltrexone, an opioid receptor antagonist, is effective in the treatment of alcohol and opioid dependence. An important limitation of the use of oral naltrexone is the lack of efficacy among patients who do not consistently take the medication. The advent of a sustained-release naltrexone addresses the problem of noncompliance. Naltrexone can be compounded into microcapsules that can be injected or implanted, producing a clinical response lasting from 30 days to several months. Several randomized, placebo-controlled clinical trials demonstrate that sustained-release naltrexone is safe and effective for the treatment of both alcohol and opioid dependence. Sustained-release formulations of naltrexone may offer several advantages over its oral formulation with respect to medication compliance, pharmacokinetics, side effect profile and ease of use. Recently, one formulation of sustained-release naltrexone received approval from the US FDA and offers a new option for addiction treatment.