Clinical relevance of nalmefene versus placebo in alcohol treatment: reduction in mortality risk

Role of histaminergic regulation of astrocytes in alcohol use disorder

Alcohol use disorder (AUD) is a severe, yet not fully understood, mental health problem. It is associated with liver, pancreatic, and gastrointestinal diseases, thereby highly increasing the morbidity and mortality of these individuals. Currently, there is no effective and safe pharmacological therapy for AUD. Therefore, there is an urgent need to increase our knowledge about its neurophysiological etiology to develop new treatments specifically targeted at this health condition. Recent findings have shown an upregulation in the histaminergic system both in alcohol dependent individuals and in animals with high alcohol preference. The use of H3 histaminergic receptor antagonists has given promising therapeutic results in animal models of AUD. Interestingly, astrocytes, which are ubiquitously present in the brain, express the three main histamine receptors (H1, H2 and H3), and in the last few years, several studies have shown that astrocytes could play an important role in the development and maintenance of AUD. Accordingly, alterations in the density of astrocytes in brain areas such as the prefrontal cortex, ventral striatum, and hippocampus that are critical for AUD-related characteristics have been observed. These characteristics include addiction, impulsivity, motor function, and aggression. In this work, we review the current state of knowledge on the relationship between the histaminergic system and astrocytes in AUD and propose that histamine could increase alcohol tolerance by protecting astrocytes from ethanol-induced oxidative stress. This increased tolerance could lead to high levels of alcohol intake and therefore could be a key factor in the development of alcohol dependence.

A Community-Based Therapeutic Education Programme for People with Alcohol Use Disorder in France: A Qualitative Study (ETHER)

Therapeutic patient education (TPE) aims to help people with chronic disease strengthen their empowerment and psychosocial skills to better manage their condition. Although TPE has great potential for addiction medicine, studies on its benefits for reducing alcohol-related harms and increasing empowerment are sparse. We conducted a qualitative study of people with alcohol use disorder (AUD) who participated in the community-based TPE programme Choizitaconso to assess their perceptions and experiences of it. Semi-structured interviews were conducted with 16 participants who had completed the TPE programme at least six months previously. The interviews were transcribed and analysed using a sequential thematic analysis. We identified four general themes: (1) the context of participation: the TPE programme could be a strategy to facilitate engagement in AUD care; (2) representations and experiences: the programme helped to “normalize” participants’ relationship with alcohol use by increasing empowerment; (3) TPE strengths: improved knowledge about alcohol use, self-image, weight loss, self-stigma reduction; (4) TPE limitations: difficulty putting learning into practice after the programme ended. The Choizitaconso programme met participants’ health and psychosocial expectations, strengthening their empowerment and reducing self-stigma, thereby facilitating engagement in AUD care.

The World Health Organization Risk Drinking Levels Measure of Alcohol Consumption: Prevalence and Health Correlates in Nationally Representative Surveys of U.S. Adults, 2001-2002 and 2012-2013

OBJECTIVE

Little is known about change over time in the prevalence of World Health Organization (WHO) risk drinking levels (very high, high, moderate, low) and their association with health conditions, overall and by gender. The authors used two sets of nationally representative U.S. survey data to determine whether changes over time varied by gender and to examine whether health conditions related to alcohol were associated with WHO risk drinking level within each survey, and whether these associations differed by gender.

METHODS

Data on current drinkers from the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; N=26,655) and the 2012-2013 NESARC-III (N=25,659) were analyzed using logistic regression. Prevalence differences between surveys were estimated for each drinking level overall and by gender. Within each survey, prevalence differences by WHO risk drinking level were estimated for alcohol use disorder (AUD), drug use disorders, functional impairment, liver disease, and depressive and anxiety disorders.

RESULTS

In the 2012-2013 survey, the prevalences of moderate, high, and very high risk drinking were 5.9%, 3.2%, and 3.5%, respectively, representing significant increases from the prevalences in the 2001-2002 survey, which were 1.0%, 0.6%, and 0.9%, respectively. The increase for very high risk drinking among men (0.5%) was smaller than the increase among women (1.4%). Within both surveys, compared with low risk, health conditions were significantly associated with very high risk (range of prevalence differences, 2.2%-57.8%), high risk (2.6%-41.3%), and moderate risk (0.6%-29.8%) drinking. Associations were similar by gender, except that there were stronger effects for AUD in men and for functional impairment and depressive and anxiety disorders in women.

CONCLUSIONS

The increase in potentially problematic drinking levels among U.S. adults emphasizes the need for better prevention and treatment strategies. The study results support the validity of the WHO risk drinking levels, which show clinical utility as nonabstinent drinking reduction treatment goals. Such goals could engage more people in treatment, improving public health by decreasing personal and societal consequences of risk drinking.

SF-6D utility scores for alcohol use disorder status and alcohol consumption risk levels in the US population

AIMS

To estimate US population health utilities for subgroups defined by alcohol use disorder (AUD) status and consumption level.

DESIGN

Cross-sectional survey.

SETTING

Community settings in the United States (i.e. excluding institutional settings).

PARTICIPANTS

A total of 36,042 adults (age 18+) in non-institutional settings in the United States.

MEASUREMENTS

We used 12-item Short Form Survey (SF-12) data from the National Epidemiologic Survey on Alcohol and Related Conditions-III to calculate mean Short Form-6 dimension (SF-6D) utility scores across World Health Organization alcohol consumption risk levels-very high risk, high risk, medium risk, low risk and an additional abstinent level-for three groups: (1) the general population (n = 36,042), (2) individuals with life-time AUD (n = 9925) and (3) individuals with current AUD (n = 5083), and assessed minimally important differences (MIDs) between consumption levels. Each group is a subset of the previous group.

FINDINGS

The general population's mean SF-6D utility was higher than that of individuals with life-time or current AUD across all consumption risk levels (0.79 versus 0.76 for both AUD groups). For all groups, SF-6D utilities increased as consumption risk level decreased to non-abstinent levels, and reducing consumption from very high risk to any lower level was associated with a statistically significant and meaningful improvement in utility. For individuals with life-time or current AUD, becoming abstinent from high-, medium- and low-risk levels was associated with significantly and meaningfully worse utilities.

CONCLUSIONS

Higher alcohol consumption risk levels appear to be associated with lower health index scores for the general population and individuals with a history of alcohol use disorder, meaning that higher alcohol consumption is associated with worse health-related quality of life.

Reduction in World Health Organization Risk Drinking Levels and Cardiovascular Disease

BACKGROUND

Reductions in World Health Organization (WHO) risk drinking levels have recently been shown to lower the risk of multiple adverse health outcomes, but prior work has not examined reductions in WHO risk drinking levels in relation to cardiovascular disease (CVD), the leading cause of death for men and women in the United States and of global mortality. This study examined associations between reductions in WHO risk drinking levels and subsequent risk for CVD.

METHODS

In a US national survey, 1,058 very-high-risk and high-risk drinkers participated in Wave 1 interviews (2001 to 2002) and Wave 2 follow-ups (2004 to 2005). Self-reported CVD history that was communicated to the participant by a doctor or other healthcare professionals included arteriosclerosis, hypertension, angina, tachycardia, or myocardial infarction. We used logistic regression to estimate adjusted odds ratios (aOR) evaluating relationships between ≥2-level reductions in WHO risk drinking levels from Wave 1 to Wave 2 and the risk of Wave 2 CVD, controlling for baseline characteristics.

RESULTS

Reductions of ≥2 WHO risk drinking levels were associated with significantly lower odds of CVD in individuals who at Wave 1 were very-high-risk (aOR = 0.58 [0.41 to 0.80]) or high-risk drinkers (aOR = 0.81 [0.70 to 0.94]). Interaction terms showed that this relationship varied by age. Among individuals >40 years old at Wave 1, reductions of ≥2 WHO risk drinking levels were associated with significantly lower odds of CVD among very-high-risk drinkers (aOR = 0.42 [0.28 to 0.63]) but not high-risk drinkers (p = 0.50). Among individuals ≤40 years old at Wave 1, reductions of ≥2 WHO risk drinking levels were associated with significantly lower odds of CVD among high-risk drinkers (aOR = 0.50 [0.37 to 0.69]) but not very-high-risk drinkers (p = 0.27).

CONCLUSIONS

These results show that reductions in WHO risk drinking levels are associated with reduced CVD risk among very-high-risk and high-risk drinkers in the US general population, and provide further evidence that reducing high levels of drinking provides important benefit across multiple clinical domains.

Estimating Long-Term Drinking Patterns for People with Lifetime Alcohol Use Disorder

Background. There is a lack of data on alcohol consumption over time. This study characterizes the long-term drinking patterns of people with lifetime alcohol use disorders who have engaged in treatment or informal care. Methods. We developed multinomial logit models using the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) to estimate short-term transition probabilities (TPs) among the 4 World Health Organization drinking risk levels (low, medium, high, and very high risk) and abstinence by age, sex, and race/ethnicity. We applied an optimization algorithm to convert 3-year TPs from NESARC to 1-year TPs, then used simulated annealing to calibrate TPs to a propensity-scored matched set of participants derived from a separate 16-year study of alcohol consumption. We validated the resulting long-term TPs using NESARC-III, a cross-sectional study conducted on a different cohort. Results. Across 24 demographic groups, the 1-year probability of remaining in the same state averaged 0.93, 0.81, 0.49, 0.51, and 0.63 for abstinent, low, medium, high, and very high-risk states, respectively. After calibration to the 16-year study data (N = 420), resulting TPs produced state distributions that hit the calibration target. We find that the abstinent or low-risk states are very stable, and the annual probability of leaving the very high-risk state increases by about 20 percentage points beyond 8 years. Limitations. TPs for some demographic groups had small cell sizes. The data used to calibrate long-term TPs are based on a geographically narrow study. Conclusions. This study is the first to characterize long-term drinking patterns by combining short-term representative data with long-term data on drinking behaviors. Current research is using these patterns to estimate the long-term cost effectiveness of alcohol treatment.

Alcohol use disorders

Alcohol use disorders consist of disorders characterised by compulsive heavy alcohol use and loss of control over alcohol intake. Alcohol use disorders are some of the most prevalent mental disorders globally, especially in high-income and upper-middle-income countries; and are associated with high mortality and burden of disease, mainly due to medical consequences, such as liver cirrhosis or injury. Despite their high prevalence, alcohol use disorders are undertreated partly because of the high stigma associated with them, but also because of insufficient systematic screening in primary health care, although effective and cost-effective psychosocial and pharmacological interventions do exist. Primary health care should be responsible for most treatment, with routine screening for alcohol use, and the provision of a staggered treatment response, from brief advice to pharmacological treatment. Clinical interventions for these disorders should be embedded in a supportive environment, which can be bolstered by the creation of alcohol control policies aimed at reducing the overall level of consumption.

Reduction in non-abstinent World Health Organization (WHO) drinking risk levels and drug use disorders: 3-year follow-up results in the US general population

BACKGROUND

To provide information on the clinical relevance of a reduction in the World Health Organization (WHO) drinking risk categories, we examined their relationship to an important indicator of how individuals feel and function: drug use disorders (DUDs), i.e., those involving substances other than alcohol.

METHOD

Current drinkers in a U.S. national survey (n = 22,005) were interviewed in 2001-02 and re-interviewed 3 years later. WHO drinking risk levels and DSM-IV-defined DUD were assessed at both waves. The relationship of changes in WHO drinking risk levels to the presence of DUD were examined using adjusted odds ratios (aOR).

RESULTS

At Wave 1, 2.5% of respondents were WHO very-high-risk drinkers, and 2.5%, 4.8%, and 90.2% were high-risk, moderate-risk, and low-risk drinkers, respectively. Among Wave 1 very-high-risk drinkers, significantly lower odds of DUD at Wave 2 were predicted by reductions in WHO risk levels of one, two or three levels (aOR = 0.15, 0.01, 0.24, respectively; all p-values <.0001). Among participants who initially were drinking at lower risk levels, reductions in drinking or abstinence were generally associated with significantly lower odds of DUD, although the results were less consistent.

CONCLUSIONS

Among very-high-risk drinkers, reduction in the WHO drinking risk categories were associated with lower risk of a DUD. These results add to findings indicating that reductions in WHO drinking risk levels are a meaningful indicator of how individuals feel and function and could therefore serve as informative outcomes in alcohol clinical trials. WHO risk levels can also guide treatment goals and clinical recommendations on drinking reduction.

Reduction in non-abstinent WHO drinking risk levels and depression/anxiety disorders: 3-year follow-up results in the US general population

BACKGROUND

Non-abstinent drinking reductions that predict improvement in how individuals feel or function, such as the World Health Organization (WHO) drinking risk levels, may be useful outcomes in clinical trials for alcohol use disorders (AUD).

METHODS

Current drinkers in a U.S. national survey (n = 22,005) were interviewed in 2001-02 (Wave 1) and re-interviewed 3 years later (Wave 2). WHO drinking risk levels, a 4- level categorization system (very-high-risk, high-risk, moderate-risk, and low-risk drinkers) defined using estimated mean ethanol consumption (grams) per day in the prior 12 months, and DSM-IV depressive and anxiety disorders were assessed at both waves. Logistic regression was used to produce adjusted odds ratios (aOR) testing the associations of changes between Wave 1 and Wave 2 WHO risk levels to the presence or persistence of depression and/or anxiety disorder by each initial Wave 1 risk level.

RESULTS

Among Wave 1 very-high-risk drinkers, lower odds of depression and/or anxiety disorders at Wave 2 were predicted by reductions in WHO risk levels of one-, two- or three-levels (aOR = 0.42, 0.37, 0.67, p-values 0.04-<.0001), as was the persistence of depression and/or anxiety disorders among those with such disorders at Wave 1 (aOR = 0.37, 0.29, 0.51, p-values .03-<.0001). Results were less consistent for participants initially drinking at lower risk levels.

CONCLUSIONS

Among very-high-risk drinkers, reductions in the WHO drinking risk categories were associated with lower risk of depression and/or anxiety disorders. These results add to findings indicating reductions in WHO risk levels are a meaningful indicator of how individuals feel and function.

Reduction in Nonabstinent WHO Drinking Risk Levels and Change in Risk for Liver Disease and Positive AUDIT-C Scores: Prospective 3-Year Follow-Up Results in the U.S. General Population

BACKGROUND

Abstinence is often the treatment aim for alcohol use disorders (AUD), but this may deter individuals who prefer drinking reduction goals from entering treatment, and be an overly restrictive end point in alcohol clinical trials. Nonabstinent drinking reductions that predict improvement in how individuals feel or function may be useful clinical trial outcomes, for example, reductions in the 4-category World Health Organization (WHO) drinking risk levels. To investigate the clinical relevance of these reductions, we examined their relationship with 2 outcomes of interest to medical providers: liver disease, and positive scores on an alcohol screening measure.

METHODS

Current drinkers in a U.S. national survey (n = 21,925) were interviewed in 2001 to 2002 (Wave 1) and re-interviewed 3 years later (Wave 2). WHO drinking risk levels, liver disease, and the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) were assessed at both waves. Adjusted odds ratios (aORs) were used to indicate the association of change in WHO drinking risk levels with Wave 2 liver disease and AUDIT-C scores.

RESULTS

Wave 1 very-high-risk drinkers who reduced 1, 2, or 3 WHO drinking risk levels had significantly lower odds of Wave 2 liver disease (aORs = 0.34, 0.23, 0.17) and positive AUDIT-C scores (aORs = 0.27, 0.09, 0.03). Wave 1 high-risk drinkers who reduced 1 or 2 WHO risk levels had significantly lower odds of positive AUDIT-C scores (aORs = 0.61, 0.25). Adjusting for alcohol dependence or AUDIT-C scoring variations did not affect results.

CONCLUSIONS

In the highest-risk drinkers, reductions in WHO drinking risk levels predicted lower likelihood of liver disease and positive AUDIT-C scores. Results add to findings that reductions in the 4-category WHO drinking risk levels are a meaningful indicator of how individuals feel and function, and could serve as nonabstinent end points in clinical trials. Results also connect the WHO risk drinking levels to commonly used alcohol screening questions, which may be more familiar to healthcare providers.

Effects of naltrexone on alcohol self-administration and craving: meta-analysis of human laboratory studies

Randomized clinical trials have established the efficacy of naltrexone for reducing quantity of alcohol consumption and incidence of relapse to heavy drinking. To evaluate putative treatment mechanisms, human laboratory studies have examined naltrexone's effects on alcohol responses and self-administration during short-term medication protocols. Results from these studies are inconsistent and have yet to be examined in aggregate. This meta-analysis aimed to quantify naltrexone's effects on alcohol self-administration and craving in the context of placebo-controlled human laboratory trials. Potential moderators of medication effects were also examined. Meta-analyses of alcohol self-administration (k = 9, N = 490) and craving (k = 16, N = 748) confirmed that, under controlled experimental conditions, naltrexone reduces the quantity of consumption (Hedges' g = -.277, SE = .074, 95 percent CI = -.421, -.133, p < .001) and magnitude of self-reported craving (g = -.286, SE = .066, 95 percent CI = -.416, -.156, p < .001) relative to placebo. Subgroup and moderation analyses found no evidence that effect sizes differed by study population (dependent versus non-dependent drinkers), laboratory paradigm or duration of medication exposure. These results substantiate prior evidence for reductions in event-level craving and consumption as potential treatment mediators, also establishing effect sizes to inform future human laboratory trials. From a clinical perspective, these results may provide additional evidence regarding naltrexone's efficacy in the context of acute or subacute dosing regimens.

Change in non-abstinent WHO drinking risk levels and alcohol dependence: a 3 year follow-up study in the US general population

BACKGROUND

Alcohol dependence is often untreated. Although abstinence is often the aim of treatment, many drinkers prefer drinking reduction goals. Therefore, if supported by evidence of benefit, drinking reduction goals could broaden the appeal of treatment. Regulatory agencies are considering non-abstinent outcomes as efficacy indicators in clinical trials, including reduction in WHO drinking risk levels-very high, high, moderate, and low-defined in terms of mean ethanol consumption (in grams) per day. We aimed to study the relationship between reductions in WHO drinking risk levels and subsequent reduction in the risk of alcohol dependence.

METHODS

In this population-based cohort study, we included data from 22 005 drinkers who were interviewed in 2001-02 (Wave 1) and re-interviewed 3 years later (2004-05; Wave 2) in the US National Epidemiologic Survey on Alcohol and Related Conditions. Alcohol consumption (WHO drinking risk levels) and alcohol dependence (at least three of seven DSM-IV criteria in the previous 12 months) were assessed at both waves. We used logistic regression to test the relationship between change in WHO drinking risk levels between Waves 1 and 2, and alcohol dependence at Wave 2.

FINDINGS

At Wave 1, 2·5% (weighted proportion) of the respondents were very-high-risk drinkers, 2·5% were high-risk drinkers, 4·8% were moderate-risk drinkers, and most (90·2%) were low-risk drinkers. Reduction in WHO drinking risk level predicted significantly lower odds of alcohol dependence at Wave 2, particularly among very-high-risk drinkers (adjusted odds ratios 0·27 [95% CI 0·18-0·41] for reduction by one level, 0·17 [0·10-0·27] for two levels, and 0·07 [0·05-0·10] for three levels) and high-risk drinkers (0·64 [0·54-0·75] for one level and 0·12 [0·09-0·15] for two levels), and among those with alcohol dependence at Wave 1 (0·29 [0·15-0·57] for one level, 0·06 [0·04-0·10] for two levels, and 0·04 [0·03-0·06] for three levels in very-high-risk drinkers).

INTERPRETATION

Our results support the use of reductions in WHO drinking risk levels as an efficacy outcome in clinical trials. Because these risk levels can be readily translated into standard drink equivalents per day of different countries, the WHO risk levels could also be used internationally to guide treatment goals and clinical recommendations on drinking reduction.

FUNDING

US National Institute on Alcohol Abuse and Alcoholism, New York State Psychiatric Institute, the Alcohol Clinical Trials Initiative.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Nalmefene for the management of alcohol dependence: review on its pharmacology, mechanism of action and meta-analysis on its clinical efficacy

Nalmefene, a mu- and delta-opioid receptor (MOR, DOR) antagonist and a partial kappa-opioid receptor (KOR) agonist, is approved in the European Union and other countries for the reduction of alcohol consumption in alcohol dependent patients with a high drinking risk level according to WHO ("target population"). This review presents an overview of nalmefene׳s pharmacology, its mechanisms of action and a meta-analysis on its efficacy in reducing alcohol consumption. The review was based on a systematic search of the literature. Random effects meta-analyses were performed on published and unpublished trials directed at drinking reduction using the changes in heavy drinking days (HDDs) and daily total alcohol consumption (TAC) from baseline to the primary endpoint. For each included study and each dose, Hedges' g was used as an unbiased estimator of the standardised mean differences between nalmefene and placebo. Preclinical data suggests that nalmefene counters alcohol-induced dysregulations of the MOR/endorphine and the KOR/dynorphin system. Evidence further suggests that reduced alcohol consumption is an effective treatment strategy that appeals to patients not ready for abstinence. Finally, meta-analyses confirmed the efficacy of 20mg nalmefene for reducing HDDs in the ITT population (Hedge׳s g=-0.20; 95% CI -0.30 to -0.09) and the target population (Hedge׳s g=-0.33; 95% CI -0.48 to -0.18). Similar results were seen for TAC. Several meta-analyses, including this new meta-analysis, support nalmefene׳s efficacy in reducing alcohol consumption. In conclusion, because it does not require abstinence, this treatment has the potential to motivate more patients for treatment and thus helps to address a major public health concern.

Evaluation in alcohol use disorders - insights from the nalmefene experience

Nalmefene was the first treatment approved by the European Medicines Agency for reducing alcohol consumption in adult patients with alcohol dependence. It is often presented as a paradigm shift in therapeutics, but major issues limit the interpretation of the evidence supporting its use. The randomised trials submitted provided no evidence of harm reduction, the differences on consumption outcomes were of questionable clinical relevance, the target population was defined a posteriori and the drug was compared to a placebo although naltrexone was already used off-label. No post-approval randomised study is currently designed to clearly address these issues. In addition, nalmefene trials have been uncritically cited, even in guidelines. This experience reveals weaknesses in drug evaluations in alcohol dependence, which call for changes. We propose to dispense with alcohol consumption as a surrogate outcome, to consider comparative effectiveness issues, and to recommend randomised post-approval studies in case of controversial approval.

Lipophilic nalmefene prodrugs to achieve a one-month sustained release

Nalmefene is an opioid antagonist which as a once-a-day tablet formulation has recently been approved for reducing ethanol intake in alcoholic subjects. In order to address the compliance issue in this patient population, a number of potential nalmefene prodrugs were synthesized with the aim of providing a formulation that could provide plasma drug concentrations in the region of 0.5-1.0ng/mL for a one-month period when dosed intramuscular to dogs or minipigs. In an initial series of studies, three different lipophilic nalmefene derivatives were evaluated: the palmitate (C16), the octadecyl glutarate diester (C18-C5) and the decyl carbamate (CB10). They were administered intramuscularly to dogs in a sesame oil solution at a dose of 1mg-eq. nalmefene/kg. The decyl carbamate was released relatively quickly from the oil depot and its carbamate bond was too stable to be used as a prodrug. The other two derivatives delivered a fairly constant level of 0.2-0.3ng nalmefene/mL plasma for one month and since there was no significant difference between these two, the less complex palmitate monoester was chosen to demonstrate that dog plasma nalmefene concentrations were dose-dependent at 1, 5 and 20mg-eq. nalmefene/kg. In a second set of experiments, the effect of the chain length of the fatty acid monoester promoieties was examined. The increasingly lipophilic octanoate (C8), decanoate (C10) and dodecanoate (C12) derivatives were evaluated in dogs and in minipigs, at a dose of 5mg-eq. nalmefene/kg and plasma nalmefene concentrations were measured over a four-week period. The pharmacokinetic profiles were very similar in both species with Cmax decreasing and Tmax increasing with increasing fatty acid chain length and the target plasma concentrations (0.5-1.0ng/mL over a month-long period) were achieved with the dodecanoate (C12) prodrug. These data therefore demonstrate that sustained plasma nalmefene concentrations can be achieved in both dog and minipig using nalmefene prodrugs and that the pharmacokinetic profile of nalmefene can be tuned by varying the length of the alkyl group.

Nalmefene for the treatment of alcohol use disorders: recent data and clinical potential

INTRODUCTION

Few pharmacotherapies are available for alcoholism. Numerous studies indicate the involvement of the opioid-endorphin system in mediating the reinforcing effects of alcohol via dopaminergic neurons. The opioid antagonist naltrexone was found to be effective in alcohol treatment, and the European Medicines Agency has now approved the mu-opioid antagonist und partial kappa agonist nalmefene.

AREAS COVERED

This article presents background information on the chemistry of nalmefene and pre-clinical and clinical findings. The three relevant Phase III studies, all of which followed a harm-reduction, "as needed" approach and found reduced alcohol consumption with nalmefene 18 (20) mg, are discussed in detail.

EXPERT OPINION

The integration of the "as needed" approach into conventional psychosocial alcohol therapies may be challenging but offers the opportunity to reach otherwise not treated patients. Nalmefene is the first medication to be approved specifically in this indication and seems to be most suitable for patients with alcohol misuse or a rather low physical dependence on alcohol who do not require immediate detoxification or inpatient treatment. Although a categorical distinction between patients who want to stop heavy drinking or drinking at all over time may be somewhat hypothetical, nalmefene offers new treatment options to patients with alcohol use disorder.

Ventral Tegmental Area Afferents and Drug-Dependent Behaviors

Drug-related behaviors in both humans and rodents are commonly thought to arise from aberrant learning processes. Preclinical studies demonstrate that the acquisition and expression of many drug-dependent behaviors involves the ventral tegmental area (VTA), a midbrain structure comprised of dopamine, GABA, and glutamate neurons. Drug experience alters the excitatory and inhibitory synaptic input onto VTA dopamine neurons, suggesting a critical role for VTA afferents in mediating the effects of drugs. In this review, we present evidence implicating the VTA in drug-related behaviors, highlight the diversity of neuronal populations in the VTA, and discuss the behavioral effects of selectively manipulating VTA afferents. Future experiments are needed to determine which VTA afferents and what neuronal populations in the VTA mediate specific drug-dependent behaviors. Further studies are also necessary for identifying the afferent-specific synaptic alterations onto dopamine and non-dopamine neurons in the VTA following drug administration. The identification of neural circuits and adaptations involved with drug-dependent behaviors can highlight potential neural targets for pharmacological and deep brain stimulation interventions to treat substance abuse disorders.

Risks and Benefits of Nalmefene in the Treatment of Adult Alcohol Dependence: A Systematic Literature Review and Meta-Analysis of Published and Unpublished Double-Blind Randomized Controlled Trials

BACKGROUND

Nalmefene is a recent option in alcohol dependence treatment. Its approval was controversial. We conducted a systematic review and meta-analysis of the aggregated data (registered as PROSPERO 2014:CRD42014014853) to compare the harm/benefit of nalmefene versus placebo or active comparator in this indication.

METHODS AND FINDINGS

Three reviewers searched for published and unpublished studies in Medline, the Cochrane Library, Embase, ClinicalTrials.gov, Current Controlled Trials, and bibliographies and by mailing pharmaceutical companies, the European Medicines Agency (EMA), and the US Food and Drug Administration. Double-blind randomized clinical trials evaluating nalmefene to treat adult alcohol dependence, irrespective of the comparator, were included if they reported (1) health outcomes (mortality, accidents/injuries, quality of life, somatic complications), (2) alcohol consumption outcomes, (3) biological outcomes, or (4) treatment safety outcomes, at 6 mo and/or 1 y. Three authors independently screened the titles and abstracts of the trials identified. Relevant trials were evaluated in full text. The reviewers independently assessed the included trials for methodological quality using the Cochrane Collaboration tool for assessing risk of bias. On the basis of the I2 index or the Cochrane's Q test, fixed or random effect models were used to estimate risk ratios (RRs), mean differences (MDs), or standardized mean differences (SMDs) with 95% CIs. In sensitivity analyses, outcomes for participants who were lost to follow-up were included using baseline observation carried forward (BOCF); for binary measures, patients lost to follow-up were considered equal to failures (i.e., non-assessed patients were recorded as not having responded in both groups). Five randomized controlled trials (RCTs) versus placebo, with a total of 2,567 randomized participants, were included in the main analysis. None of these studies was performed in the specific population defined by the EMA approval of nalmefene, i.e., adults with alcohol dependence who consume more than 60 g of alcohol per day (for men) or more than 40 g per day (for women). No RCT compared nalmefene with another medication. Mortality at 6 mo (RR = 0.39, 95% CI [0.08; 2.01]) and 1 y (RR = 0.98, 95% CI [0.04; 23.95]) and quality of life at 6 mo (SF-36 physical component summary score: MD = 0.85, 95% CI [-0.32; 2.01]; SF-36 mental component summary score: MD = 1.01, 95% CI [-1.33; 3.34]) were not different across groups. Other health outcomes were not reported. Differences were encountered for alcohol consumption outcomes such as monthly number of heavy drinking days at 6 mo (MD = -1.65, 95% CI [-2.41; -0.89]) and at 1 y (MD = -1.60, 95% CI [-2.85; -0.35]) and total alcohol consumption at 6 mo (SMD = -0.20, 95% CI [-0.30; -0.10]). An attrition bias could not be excluded, with more withdrawals for nalmefene than for placebo, including more withdrawals for safety reasons at both 6 mo (RR = 3.65, 95% CI [2.02; 6.63]) and 1 y (RR = 7.01, 95% CI [1.72; 28.63]). Sensitivity analyses showed no differences for alcohol consumption outcomes between nalmefene and placebo, but the weight of these results should not be overestimated, as the BOCF approach to managing withdrawals was used.

CONCLUSIONS

The value of nalmefene for treatment of alcohol addiction is not established. At best, nalmefene has limited efficacy in reducing alcohol consumption.