An open multicentric study evaluating 4-hydroxybutyric acid sodium salt in the medium-term treatment of 179 alcohol dependent subjects. GHB Study Group

Long-term Efficacy and Safety of Sodium Oxybate in Treating Alcohol Use Disorder: A Systematic Review and Meta-Analysis

BACKGROUND

Worldwide, three million deaths each year are reported due to the harmful use of alcohol. To date, only a few drugs have been approved for the treatment of Alcohol Use Disorder (AUD). This systematic review and meta-analysis aim to assess the long-term efficacy and safety of sodium oxybate (SMO) treatment in patients with AUD.

METHODS

We followed the PRISMA statement guidelines and searched PubMed and ISI Web of Science to retrieve the studies of interest. In total, 13 studies on long-term (>12 weeks) SMO administration in patients with AUD were included in this systematic review, and 7 were included in the metaanalysis.

RESULTS

Overall, the abstinence rate after 12 weeks of treatment was similar in the SMO and placebo groups, while it was significantly in favour of SMO compared to Naltrexone (NTX). The completion rate was similar in all three conditions. Mean corpuscular volume (MCV) levels favoured SMO over NTX, while Alcohol Craving Scale (ACS) scores did not favour SMO. The incidence of adverse reactions varied widely between studies.

CONCLUSION

SMO in the chronic treatment of patients with AUD showed no superiority to placebo in our analysis of published RCTs, although many observational studies reported its beneficial effect in the long term. On the contrary, SMO was superior to NTX treatment on abstinence. The rate of study completion was similar in the three groups. Safety was not an issue in any of the studies included. Further studies are needed to better assess SMO efficacy and safety in the long term.

Sodium oxybate: A comprehensive review of efficacy and safety in the treatment of alcohol withdrawal syndrome and alcohol dependence

Alcohol dependence (AD) significantly impacts public health, affecting 3.4% of people aged 18-64 and contributing to around 12% of overall mortality. Individuals with AD have a markedly reduced life expectancy, dying up to 28 years earlier than the general population. Current treatments for AD show limited efficacy, with many patients not responding to these interventions, highlighting the need for new therapeutic options with novel mechanisms of action. Sodium oxybate (SMO), the sodium salt of GHB, is one such candidate, pharmacologically similar to alcohol; it acts on several neurotransmitters including GABA, potentially mitigating withdrawal symptoms and craving for alcohol. SMO has been clinically used in Italy and Austria since the 1990s, approved for treating alcohol withdrawal syndrome (AWS) and for maintaining abstinence in AD patients. Several randomized clinical trials (RCTs) and meta-analyses showed evidence of SMO to be effective and safe in these indications. For AWS, SMO was more effective than placebo and as effective as benzodiazepines in reducing withdrawal symptoms. For maintaining abstinence, SMO significantly improved continuous abstinence duration and abstinence rate compared to placebo. Comprehensive clinical data indicate that SMO is well-tolerated, with main adverse effects being mild, such as dizziness and vertigo, and serious adverse events being rare. The effectiveness and safety of SMO, coupled with its approval in two EU countries affirm its potential as a treatment option for AD, particularly in severe cases. Further RCTs, especially with stratification by severity of dependence, are suggested to refine our understanding of its efficacy across different patient subgroups.

Serotonin transporter knockdown relieves depression-like behavior and ethanol-induced CPP in mice after chronic social defeat stress

Patients with stress-triggered major depression disorders (MDD) can often seek comfort or temporary relief through alcohol consumption, as they may turn to it as a means of self-medication or coping with overwhelming emotions. The use of alcohol as a coping mechanism for stressful events can escalate, fostering a cycle where the temporary relief it provides from depression can deepen into alcohol dependence, exacerbating both conditions. Although, the specific mechanisms involved in stress-triggered alcohol dependence and MDD comorbidities are not well understood, a large body of literature suggests that the serotonin transporter (SERT) plays a critical role in these abnormalities. To further investigate this hypothesis, we used a lentiviral-mediated knockdown approach to examine the role of hippocampal SERT knockdown in social defeat stress-elicited depression like behavior and ethanol-induced place preference (CPP). The results showed that social defeat stress-pro depressant effects were reversed following SERT knockdown demonstrated by increased sucrose preference, shorter latency to feed in the novelty suppressed feeding test, and decreased immobility time in the tail suspension and forced swim tests. Moreover, and most importantly, social stress-induced ethanol-CPP acquisition and reinstatement were significantly reduced following hippocampal SERT knockdown using short hairpin RNA shRNA-expressing lentiviral vectors. Finally, we confirmed that SERT hippocampal mRNA expression correlated with measures of depression- and ethanol-related behaviors by Pearson's correlation analysis. Taken together, our data suggest that hippocampal serotoninergic system is involved in social stress-triggered mood disorders as well as in the acquisition and retrieval of ethanol contextual memory and that blockade of this transporter can decrease ethanol rewarding properties.

Ethnopharmacological Applications Targeting Alcohol Abuse: Overview and Outlook

Excessive alcohol consumption is the cause of several diseases and thus is of a major concern for society. Worldwide alcohol consumption has increased by many folds over the past decades. This urgently calls for intervention and relapse counteract measures. Modern pharmacological solutions induce complete alcohol self-restraint and prevent relapse, but they have many side effects. Natural products are most promising as they cause fewer adverse effects. Here we discuss in detail the medicinal plants used in various traditional/folklore medicine systems for targeting alcohol abuse. We also comprehensively describe preclinical and clinical studies done on some of these plants along with the possible mechanisms of action.

Anticraving therapy for alcohol use disorder: A clinical review

Aim

In this review, the author focused on anticraving therapy for alcohol use disorder (AUD) defined by DMS‐5. A comprehensive review was carried out on the available published papers on anticraving drugs for treating AUD patients.

Methods

The author described all drugs with anticraving benefits for treating AUD patients approved by the Food and Drug Administration of the United States (US FDA) and European Medicines Agency of the European Union. Then, the commonly prescribed anticraving drugs and those under development were also described.

Results

The US FDA‐approved anticraving drugs included acamprosate and naltrexone, and those approved by European Medicines Agency were gamma‐hydroxybutyrate and nalmefene. The author also highlighted topiramate, gabapentin, ondansetron, LY196044, ifenprodil, varenicline, ABT‐436, mifepristone, citicoline, and baclofen. The putative mechanisms of action of and the use in clinical practice of those anticraving drugs were also described.

Conclusion

Although slowly developing, the field of anticraving drugs is getting into shape as a promising entity of a pharmaceutical class of drugs. Then, the author addressed on the underused issues of those recommended, and suggested anticraving drugs by the practice guideline of the American Psychiatric Association. The author urges that clinicians should be more “adventurous” in prescribing those promising drugs because benefits of those anticraving drugs are far‐outweighing the possible side effects of anticraving drugs, or the harms of untreated AUD itself.

Building better strategies to develop new medications in Alcohol Use Disorder: Learning from past success and failure to shape a brighter future

Alcohol Use Disorder (AUD) is a chronic disease that develops over the years. The complexity of the neurobiological processes contributing to the emergence of AUD and the neuroadaptive changes occurring during disease progression make it difficult to improve treatments. On the other hand, this complexity offers researchers the possibility to explore new targets. Over years of intense research several molecules were tested in AUD; in most cases, despite promising preclinical data, the clinical efficacy appeared insufficient to justify futher development. A prototypical example is that of corticotropin releasing factor type 1 receptor (CRF1R) antagonists that showed significant effectiveness in animal models of AUD but were largely ineffective in humans. The present article attempts to analyze the most recent venues in the development of new medications in AUD with a focus on the most promising drug targets under current exploration. Moreover, we delineate the importance of using a more integrated translational framework approach to correlate preclinical findings and early clinical data to enhance the probability to validate biological targets of interest.

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.

A Brief Up-Date of the Use of Sodium Oxybate for the Treatment of Alcohol Use Disorder

The treatment of alcohol use disorder (AUD) with sodium oxybate (SMO) or gamma-hydroxybutyric acid (GHB) was introduced in Italy and Austria more than 20 years and 15 years ago, respectively, and it is now widely employed to treat alcohol withdrawal syndrome (AWS) and to maintain alcohol abstinence. These indications derive from its similar structure to the inhibitory neurotransmitter γ-amino-butyric acid (GABA), exerting an ethanol-mimicking effect, because it binds to GABAB receptors. Craving for, and abuse of, SMO remain a controversial issue; even though these unfavorable effects are evident in poly-drug addicted patients and in those with psychiatric diagnosis of borderline personality disorder. In addition, despite cases of severe intoxication and deaths being widely documented when GHB is used as "street drug"; its clinical use remains safe. Thus, the aim of the present review is to examine the role of SMO in the treatment of AUD, its possible implications in reducing alcohol consumption, and cases of abuse, and severe intoxication due to SMO during its clinical use in the treatment of AUD.

Pharmacodynamic interactions of a solid formulation of sodium oxybate and ethanol in healthy volunteers

AIM

The pharmacologic effects of sodium oxybate (SO) have a number of similarities with those of alcohol. This study evaluated the pharmacodynamic interaction of SMO.IR (a solid immediate release formulation of SO) and alcohol (0.7 (males) or 0.57 (females) g kg(-1) alcohol using 40% vodka).

METHODS

In a randomized, double-blind, double-dummy, crossover trial, 24 healthy volunteers received randomly a) 2.25 g SMO.IR and placebo alcohol preparation, b) 2.25 g f SMO.IR and alcohol, c) 2.25 g SMO.IR matching placebo and alcohol and d) 2.25 g of SMO.IR matching placebo and placebo alcohol preparation. Objective and subjective cognitive parameters, adverse events and vital signs were assessed before, 15 and 165 min after treatment administration.

RESULTS

Alcohol produced the expected cognitive impairment and the expected subjective sedation rapidly after intake (from 15 min). The objective effects of SMO.IR were much less pronounced than those of alcohol. The reverse was observed for subjective complaints, which were related to lesser stimulation and greater sedation. Nevertheless, 165 min after administration this sedation feeling was less with SMO.IR than with alcohol. There was a significant interaction between SMO.IR and alcohol at 15 min (i.e. increase in alertness and stimulation and decrease in sedation). In addition, an isolated mild decrease in digit vigilance accuracy occurred at 165 min post-dose after the combination. The co-administration of SMO.IR and alcohol was safe and well-tolerated.

CONCLUSION

SMO.IR and alcohol have distinct adverse effect profiles. The objective effects of SMO.IR are much less marked than those of alcohol. No deleterious interaction was observed.

Pharmacotherapy for alcohol use disorder: current and emerging therapies

Alcohol use disorder is a heterogeneous illness with a complex biology that is controlled by many genes and gene-by-environment interactions. Several efficacious, evidence-based treatments currently exist for treating and managing alcohol use disorder, including a number of pharmacotherapies that target specific aspects of biology that initiate and maintain dangerous alcohol misuse. This article reviews the neurobiological and neurobehavioral foundation of alcohol use disorder, the mechanisms of action and evidence for the efficacy of currently approved medications for treatment, and the literature on other emerging pharmacotherapies.

Pharmacotherapy for alcoholic patients with alcoholic liver disease

PURPOSE

An update on pharmacotherapy for achieving and maintaining abstinence and mitigating hepatic damage in patients with alcoholic liver disease (ALD) is presented.

SUMMARY

Currently there are limited pharmacotherapy options for managing ALD, which encompasses a broad spectrum of disorders ranging from steatosis and alcoholic hepatitis to fibrosis, cirrhosis, and hepatocellular cancer. Individual variation in the severity, presentation, and complex pathologenesis of ALD defines barriers to effective treatment. Scoring of disease severity using validated assessment instruments should guide treatment approaches; abstinence and proper nutrition continue to be the cornerstones of management. A literature search (through December 31, 2013) identified no reports of randomized controlled trials using Food and Drug Administration (FDA)-approved medications for the treatment of alcohol dependence in ALD-spectrum disorders. Disulfiram, acamprosate, and naltrexone (oral and intramuscular), while approved by FDA for treatment of alcohol dependence, are not currently approved for use in patients with ALD. Baclofen (also not FDA-approved for use in ALD) is the only medication available in the United States with demonstrated safety and efficacy in reducing alcoholic behavior that has been formally tested in clinical trials in patients with ALD. Pharmacotherapy of alcoholic hepatitis using glucocorticoids or pentoxifylline has shown promise, but these options are reserved for severe ALD only.

CONCLUSION

Although various treatments have been investigated for ALD in patients with alcoholism, complete abstinence from alcohol is currently the only recommended form of hepatoprotection for the entire spectrum of ALD diagnoses.

Pharmacological approaches to reducing craving in patients with alcohol use disorders

Research on the concept of craving may lead to better understanding of the biobehavioural circuitries that contribute to the complexity of alcohol use disorders (AUDs). The experiences described as craving or desire to drink are often associated with physical responses such as increased salivation and heart rate, and alteration of stress hormones, as well as psychological responses such as anxiety and depression. Greater craving has been associated with an increased probability of alcohol relapse. Reversal of craving, which is understood as a symptom of protracted abstinence, offers the possibility of preventing relapses and treating alcoholism. Various medications have been studied to establish whether they are able to reduce craving; however, the results obtained from clinical studies have been inconsistent. Here, we review the interdisciplinary models developed to evaluate craving, then the different approaches used to assess and measure craving and, finally, the medications utilized and tested to lessen craving in patients suffering from AUDs.

Combined pharmacotherapies for the management of alcoholism: rationale and evidence to date

Pharmacotherapies for alcohol use disorders (AUDs) have limited efficacy. One approach to improving treatment outcomes for AUDs is to combine pharmacotherapies that have shown some efficacy as individual agents. The rationale for combining medications rests on the following principles: a combination of medications can target more than one neurotransmitter system that is dysfunctional in AUDs, can target different drinking behaviors (i.e., positive and negative reinforcement), can treat co-morbid psychiatric and medical disorders, and can minimize side effects, improving adherence to treatment by using lower doses of each drug in combination. Combined pharmacotherapy strategies may produce additive or even synergistic effects to decrease alcohol craving and consumption. Here, we reviewed the literature investigating the effect on alcohol-related outcomes of combinations of medications that have shown efficacy as single agents to reduce drinking in animal studies and clinical trials. We focused on 17 clinical studies investigating the combination of medications in AUDs, 11 of which were randomized, double-blind, and placebo-controlled. Ten of the 11 studies showed the combination to be superior to placebo, but only three showed an advantage of the combination compared with the single agent. Overall, these studies used diverse methodologies, assessments of severity, outcome measures, and adjunctive psychosocial treatments. Limitations of the current published studies and possible future directions for new combinations are discussed.

The effectiveness of pharmacological approaches in the treatment of alcohol withdrawal syndrome (AWS): a literature review

Mortality statistics for excessive alcohol consumption show no signs of abatement, with a report published in 2011 from the World Health Organization (WHO) estimating that 2.5 million people worldwide died because of their alcohol consumption. Serious physiological, psychological, social and legal problems are thought to affect many more. Alcohol withdrawal syndrome (AWS) is a potentially life-threatening condition that often occurs in those individuals who significantly reduce or stop their intake after a prolonged and excessive period of drinking. Pharmacological treatment of the AWS has traditionally been undertaken by the use of the benzodiazepines, but recent years have witnessed the emergence of several alternatives. The aim of this paper was (1) to review the evidence base supporting the use of various pharmacological agents currently employed to treat AWS, and (2) to consider the efficacy and safety of the emerging alternatives to the benzodiazepines. The Cochrane Database of Systematic Reviews, CINAHL, Embase, PsycINFO, MEDLINE and BNI databases were extensively searched in order to retrieve the maximum number of relevant articles. Reference lists from relevant literature were also used to identify other potential studies for inclusion. All studies concerned with measuring the efficacy and safety of the various pharmacological treatment options for AWS were considered and a total of 63 trials were included in this review. Findings support the use of benzodiazepines as the recommended drug of choice for the treatment of AWS in the absence of adequate evidence to support the use of alternative agents. There is a lack of evidence of a superior pharmacological agent to the benzodiazepines for the treatment of AWS. There are several studies that have shown that there are pharmacological alternatives that could compete or act as an adjunct with the benzodiazepines in terms of high efficacy and safety in the treatment of AWS, but there is a need for further quality research to be carried out before definitive conclusions can be drawn.

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.

Acamprosate in the treatment of alcoholism: a budget impact analysis for the National Health Service in Italy

Objective

Alcohol dependence is a common condition associated with high direct and indirect health care costs. The purpose of this analysis was to estimate the economic consequences of acamprosate used as adjuvant therapy in the treatment of alcoholism, defining a budget impact analysis (BIA) from the point of view of the Italian National Health Service (NHS).

Methods

We developed a model of disease evolution related to alcoholism using data from the PRAMA study. The hypothetical population included in the decision model was obtained from data from the Ministry of Health. We compared the following treatment strategies: no treatment, standard care (psychotherapy), sodium oxybate (sodium salt-4-hydroxybutyric acid), and acamprosate. The time horizon of the model was 10 years. The costs were evaluated from the NHS perspective.

Results

We simulated the path for 69,348 patients treated at the outpatient clinics of the Addiction Services (SerT), and 38,911 patients discharged from hospital. Patients in the acamprosate group had lower alcohol-related events, with a reduction of the total cost. The BIA shows that the increase in the use of acamprosate was associated with a progressive decrease of total costs, calculated as the sum of the diagnosis-related groups (DRG), rehabilitation, and drug costs. The increasing use of acamprosate instead of standard care and sodium oxybate would generate cost savings up to over €6 million over 10 years of simulation.

Conclusion

The estimates in the model are based on hypothetical situations; the assumptions of the model as well as their specific impact on treatment effect estimations and clinical implications should be validated in real life. Public health care authorities would benefit from mathematical models designed to estimate the future burden of alcohol dependence together with the impact of treatment and the potential to reduce the incidence and progression of this condition, and the costs of its complications.

Dihydrocodeine/Agonists for alcohol dependents

OBJECTIVE

Alcohol addiction too often remains insufficiently treated. It shows the same profile as severe chronic diseases, but no comparable, effective basic treatment has been established up to now. Especially patients with repeated relapses, despite all therapeutic approaches, and patients who are not able to attain an essential abstinence to alcohol, need a basic medication. It seems necessary to acknowledge that parts of them need any agonistic substance, for years, possibly lifelong. For >14 years, we have prescribed such substances with own addictive character for these patients.

METHODS

We present a documented best possible practice, no designed study. Since 1997, we prescribed Dihydrocodeine (DHC) to 102 heavily alcohol addicted patients, later, also Buprenorphine, Clomethiazole (>6 weeks), Baclofen, and in one case Amphetamine, each on individual indication. This paper focuses on the data with DHC, especially. The Clomethiazole-data has been submitted to a German journal. The number of treatments with the other substances is still low.

RESULTS

The 102 patients with the DHC treatment had 1367 medically assisted detoxifications and specialized therapies before! The 4 years-retention rate was 26.4%, including 2.8% successfully terminated treatments. In our 12-steps scale on clinical impression, we noticed a significant improvement from mean 3.7 to 8.4 after 2 years. The demand for medically assisted detoxifications in the 2 years remaining patients was reduced by 65.5%. Mean GGT improved from 206.6 U/l at baseline to 66.8 U/l after 2 years. Experiences with the other substances are similar but different in details.

CONCLUSION

Similar to the Italian studies with GHB and Baclofen, we present a new approach, not only with new substances, but also with a new setting and much more trusting attitude. We observe a huge improvement, reaching an almost optimal, stable, long term status in around 1/4 of the patients already. Many further optimizations are possible.

Anti-Alcohol and Anxiolytic Properties of a New Chemical Entity, GET73

N-[(4-trifluoromethyl)benzyl]4-methoxybutyramide (GET73) is a newly synthesized compound structurally related to the clinically used, alcohol-substituting agent, gamma-hydroxybutyric acid (GHB). The present study was designed to assess whether GET73 may share with GHB the capacity to reduce alcohol intake in rats. Additionally, the effect of treatment with GET73 on anxiety-related behaviors and cognitive tasks in rats was investigated. A series of in vitro binding assays investigated the capacity of GET73 to bind to the GHB binding site and multiple other receptors. GET73 (10(-9)-10(-3) M) failed to inhibit [(3)H]GHB binding at both high- and low-affinity GHB recognition sites in rat cortical membranes. GET73 displayed minimal, if any, binding at dopamine, serotonin, GABA, and glutamate receptors in membranes from different rat brain areas. Acute treatment with low-to-moderate, non-sedative doses of GET73 (5-50 mg/kg, i.g. or i.p.) (a) reduced alcohol intake and suppressed "alcohol deprivation effect" (a model of alcohol relapse) in selectively bred, Sardinian alcohol-preferring (sP) rats, (b) exerted anxiolytic effects in Sprague-Dawley (SD) and sP rats exposed to the Elevated Plus Maze test, and (c) tended to induce promnestic effects in SD rats exposed to a modified water version of the Hebb-Williams maze test. Although the mechanism of GET73 action is currently unknown, the results of the present study suggest that GET73 has a multifaceted pharmacological profile, including the capacity to reduce alcohol drinking and anxiety-related behaviors in rats.

Substitution therapy for alcoholism: time for a reappraisal?

A number of compounds already in use as medications for various indications substitute for ethanol at clinically relevant brain pathways, in particular, at gamma-aminobutyric acid (GABA) receptors. Nevertheless, although substitute medications have been recognized for heroin and tobacco dependence, patients with alcohol dependence are rarely offered an analogous approach. Benzodiazepines may have paradoxical effects, and abuse and dependence are known. Baclofen (GABA(B) agonist) has not been associated with dependence or misuse and has been effective in several trials in preventing relapse, although research is required to establish the optimal dosing regimen. GABA-ergic anticonvulsants, helpful in treating withdrawal, have yet to emerge as effective in relapse prevention. Clomethiazole and sodium oxybate, the latter having been shown to be effective in relapse prevention, have incurred a reputation for dependence and abuse. However, data have emerged showing that the risk of abuse of sodium oxybate is lower than many clinicians had foreseen. For a condition where existing therapies are only effective in a proportion of patients, and which has high morbidity and mortality, the time now seems right for reappraising the use of substitute prescribing for alcohol dependence.

Suppression by γ-Hydroxybutyric Acid of "Alcohol Deprivation Effect" in Rats: Preclinical Evidence of its anti-Relapse Properties

γ-Hydroxybutyric acid (GHB) reduces (a) alcohol intake and alcohol motivational properties in alcohol-preferring rats and (b) alcohol drinking and craving for alcohol in human alcoholics. The present study was designed to extend to relapse-like drinking the capacity of GHB to suppress different alcohol-related behaviors in alcohol-preferring rats. The "alcohol deprivation effect," defined as the temporary increase in alcohol intake occurring in laboratory animals after a period of alcohol deprivation, was used as model of alcohol relapse. Acute administration of non-sedative doses of GHB (0, 100, 200, and 300 mg/kg, i.p.) resulted in the complete suppression of the extra-amount of alcohol consumed by Sardinian alcohol-preferring rats during the first hour of re-access to alcohol after a 14-day period of deprivation. These data demonstrate that GHB suppressed relapse-like drinking in a rat model of excessive alcohol consumption.

Long-term γ-hydroxybutyric acid (GHB) and disulfiram combination therapy in GHB treatment-resistant chronic alcoholics

Leading Italian studies support the use of γ-hydroxybutyric acid (GHB), not only in the treatment of the alcohol withdrawal syndrome, but also in maintaining alcohol abstinence. GHB gives a better result than naltrexone and disulfiram in maintaining abstinence, and it has a better effect on craving than placebo or disulfiram. The problem is that about 30–40% of alcoholics are non-responders to GHB therapy. In our clinical practice, we speculate that by combining disulfiram with GHB treatment we may be able to achieve a kind of ‘antagonist’ effect by using the ‘psychological threat’ of disulfiram (adversative effect) while taking advantage of the anticraving effect of GHB, despite the limitation of its ‘non-blockade’ effect on alcohol. In this context, to improve the outcome in GHB long-term treated alcoholics, we added disulfiram to GHB in the management of GHB treatment-resistant alcoholics. In this study we compared retention in treatment of 52 patients who were treated with the GHB-disulfiram combination for up to six months, with retention for the same subjects considering their most recent unsuccessful outpatient long-term treatment with GHB only. An additional comparison was carried out on the days of complete abstention from alcohol. Thirty four patients (65.4%) successfully completed the protocol and were considered to be responders; 18 (34.6%) left the programme, and were considered to be non-responders. Considering the days of complete abstinence from alcohol, 36 patients stayed in treatment longer with the GHB-Disulfiram combination, 12 stayed for a shorter time and four for the same time. The results of this study seem to indicate a higher efficacy of the GHB-disulfiram association compared with GHB alone. Randomized controlled trials are now needed to verify this hypothesis.

Acute toxicity and withdrawal syndromes related to γ-hydroxybutyrate (GHB) and its analogues γ-butyrolactone (GBL) and 1,4-butanediol (1,4-BD)

Gamma-hydroxybutyrate (GHB) has been used as a recreational drug since the 1990s and over the last few years there has been increasing use of its analogues gamma-butyrolactone (GBL) and to a lesser extent 1,4-butanediol (1,4BD). This review will summarize the literature on the pharmacology of these compounds; the patterns and management of acute toxicity associated with their use; and the clinical patterns of presentation and management of chronic dependency associated with GHB and its analogues.

Intravenous self-administration of γ-hydroxybutyrate (GHB) in baboons

BACKGROUND

Abuse of gamma-hydroxybutyrate (GHB) poses a public health concern. In previous studies, intravenous (IV) self-administration of GHB doses up to 10 mg/kg was not maintained in non-human primates under limited-access conditions, which was inconsistent with the usual good correspondence between drugs abused by humans and those self-injected by laboratory animals.

METHODS

Self-administration of GHB was studied in 10 baboons using procedures standard for our laboratory to assess drug abuse liability. Each self-injection depended on completion of 120 or 160 lever responses. Sessions ran continuously; a 3-h timeout limited the number of injections per 24h to 8. Self-injection was established at 6-8 injections/day with cocaine (0.32 mg/kg/injection) prior to substitution of each GHB dose (3.2-178 mg/kg/injection) or vehicle for 15 days. Food pellets were available 24h/day.

RESULTS

GHB maintained significantly greater numbers of injections when compared to vehicle in 6 of the 9 baboons that completed GHB evaluations that included 32 mg/kg/injection or higher. The baboons that self-administered GHB at high rates were ones for which GHB was the first drug each had tested under the 24-h/day cocaine baseline procedure. Self-injection of the highest doses of GHB decreased food-maintained responding.

CONCLUSIONS

High-dose GHB can function as a reinforcer in non-human primates under 24-h access, but self-administration history may be important. The findings are consistent with the demonstrated abuse liability of GHB in humans, and remove GHB as an exception to the typical good correspondence between those drugs abused by humans and those self-administered by nonhuman primates.

Behavioral effects of gamma-hydroxybutyrate in humans

Despite the therapeutic use and abuse potential of gamma-hydroxybutyrate (GHB or Xyrem), relatively few studies have examined the behavioral effects of GHB in humans under controlled laboratory conditions. Thus, this eight-session study examined in 10 non-substance-abusing volunteers the behavioral effects of GHB at each of the following doses: 0, 0.32, 0.56, 0.75, 1.0, 1.8, 2.4, 3.2 g/70 kg, orally. Order of dose testing was random, except that the first two participants received active doses in ascending order and 2.4 g/70 kg was always tested before 3.2 g/70 kg. Before drug administration and at several postdrug time points, self-report, observer report, physiological, and psychomotor performance measures were obtained. Analyses based on area under the curve showed that GHB produced dose-related increases in subjective ratings of sedative-like, stimulant-like, positive mood, and dissociative effects, but no changes in psychomotor performance measures or blood pressure. Analyses based on peak effects generally showed dose-related increases in ratings indicating sedative-like, dissociative, and drug liking, although some measures showed U-shaped dose-related changes. These initial findings suggest that GHB at doses of 0.32-3.2 g/70 kg produces dissociative, sedating and some stimulant-like effects in humans without a history of sedative abuse.

Gamma-hydroxybutyrate (GHB) for treatment of alcohol withdrawal and prevention of relapses

BACKGROUND

Chronic excessive alcohol consumption may lead to dependence, and to alcohol withdrawal syndrome (AWS) in case of abrupt drinking cessation. Gamma-hydroxybutyric acid (GHB) can prevent and suppress withdrawal symptoms, and improve the medium-term abstinence rate. A clear balance between effectiveness and harmfulness has not been yet established.

OBJECTIVES

To evaluate the efficacy and safety of GHB for treatment of AWS and prevention of relapse

SEARCH STRATEGY

We searched Cochrane Drugs and Alcohol Group' Register of Trials (October 2008), PubMed, EMBASE, CINAHL (January 2005 - October 2008), EconLIT (1969 to February 2008), reference list of retrieved articles

SELECTION CRITERIA

Randomized controlled trials (RCTs) and Controlled Prospective Studies (CPS) evaluating the efficacy and the safety of GHB vs placebo or other pharmacological treatments.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed the methodological quality of studies.

MAIN RESULTS

Thirteen RCTs were included. Eleven studies were conducted in Italy.For withdrawal syndrome, comparing GHB 50mg with placebo, results from 1 study, 23 participants favour GHB for withdrawal symptoms: WMD -12.1 (95% CI, -15.9 to -8.29) and side effects were more frequent in the placebo group: RR 16.2 (95% CI, 1.04 to 254.9).In the comparison with Chlormetiazole, for GHB 50mg, results from 1 study, 21 participants favour GHB for withdrawal symptoms: MD -3.40 (95% CI -5.09 to -1.71), for GHB 100mg, results from 1 study, 98 participants favour anticonvulsants for side effects: RR 1.84 (95% CI 1.19 to 2.85).At mid-term, comparing GHB with placebo, results favour GHB for abstinence rate (RR 5.35; 1.28-22.4), controlled drinking (RR 2.13; 1.07-5.54), relapses (RR 0.36; 0.21-0.63), and number of daily drinks (WMD -4.60; -6.18 to -3.02). GHB performed better than NTX and Disulfiram on abstinence (RR 2.59; 1.35-4.98, RR 1.66; 0.99-2.80 respectively). The association of GHB and NTX was better than NTX on abstinence (RR 12.2; 1.79-83.9), as well was the association of NTX, GHB and Escitalopram versus Escitalopram alone (RR 4.58; 1.28-16.5). For Alcohol Craving Scale results favour GHB versus placebo (WMD -1.90; -2.45 to 1.35) and Disulfiram (WMD -1.40; -1.86 to-0.94).

AUTHORS' CONCLUSIONS

GHB 50mg is effective compared to placebo in the treatment of AWS, and in preventing relapses in previously detoxified alcoholics at 3 months follow-up, but the results of this review do not provide sufficient evidence in favour of GHB compared to benzodiazepines and Chlormethiazole for AWS prevention. GHB is better than NTX and Disulfiram in maintaining abstinence and it has a better effect on craving than placebo and Disulfiram. Side effects of GHB are not statistically different from those with BZD, NTX or Disulfiram. However, concern has been raised regarding the risk of developing addiction, misuse or abuse, especially in polydrug abusers.

Calcium and cAMP signaling induced by gamma-hydroxybutyrate receptor(s) stimulation in NCB-20 neurons

The NCB-20 neurohybridoma cells differentiated with dibutyryl-cyclic-AMP represent an interesting model to study several components of the gamma-hydroxybutyrate (GHB) system in brain. In particular, an active Na(+)-dependent uptake and a depolarization-evoked release of GHB is expressed by these cells, together with high affinity specific binding sites for this substance. However, only little is known about cellular mechanisms following GHB receptor(s) stimulation in these neurons. Electrophysiological data indicate that GHB can differently affect Ca(2+) currents. L-type calcium channels were typically inhibited by GHB when NCB-20 cells were depolarized. In contrast, when NCB-20 cells were at resting potential, GHB induced a specific Ca(2+) entry through T-type calcium channels. In this study, we investigated the effect induced on cytosolic free Ca(2+) level and cAMP production by GHB receptor(s) stimulated with micromolar concentrations of GHB or structural analogues of GHB. Ca(2+) movements studied by cellular imaging were dose-dependently increased but disappeared for GHB concentrations >25 microM. In addition, nanomolar doses of GHB inhibited forskolin-stimulated adenylate cyclase. This effect was also rapidly desensitized at higher GHB concentrations. Acting as an antagonist, NCS-382 decreased GHB receptor(s) mediated cAMP and calcium signals. The agonist NCS-356 mimicked GHB effects which were not affected by the GABA(B) receptor antagonist CGP-55-845. Our results reveal the occurrence of Ca(2+)-dependent adenylate cyclase inhibition in NCB-20 neurons after GHB receptor(s) stimulation by GHB concentrations <50 microM. Above this dose, GHB effects were inactivated. In addition, at GHB concentrations exceeding 50 microM, GTP-gammaS binding was also reduced, confirming the desensitization of GHB receptor(s). Taken together, these results support the existence in NCB-20 neurons of GHB receptors belonging to GPCR family that may recruit various G protein subtypes.

A review of tolerability and abuse liability of gamma-hydroxybutyric acid for insomnia in patients with schizophrenia

BACKGROUND

Approved therapeutic uses for gamma-hydroxybutyric acid (GHB) (or sodium oxybate), a gamma-aminobutyric acid type B and GHB receptor agonist, include narcolepsy in the United States and Europe and alcohol abuse treatment in Italy. Possible efficacy of GHB in schizophrenia has also been proposed. A tolerability concern regarding use of GHB is its abuse potential. Given the high comorbidity of substance disorders and schizophrenia, a systematic assessment of the published literature is crucial.

OBJECTIVE

The aim of this review was to assess the tolerability and abuse liability of GHB in the context of future clinical studies as a potential treatment for insomnia in patients with schizophrenia.

METHODS

A literature search in English (inception through April 2009, inclusive) was conducted of MEDLINE, EMBASE, and PsycINFO using the search term GHB. All articles whose abstracts mentioned human use of GHB were read in their entirety. The reference sections of identified articles were reviewed for publications that might have been missed by the initial search.

RESULTS

GHB is abused by a small percentage of people (<1%) as a "club drug" and is commonly associated with enhanced sexual experiences (65%), euphoria (41%), somnolence (71%), and confusion (24%), according to a recent study. A review of all available emergency room case series suggests that while GHB can be associated with serious coma necessitating intubation, the number of reported fatal cases associated with GHB appears limited. Clarity on the lethality of GHB is complicated by instability of GHB in postmortem samples and frequent concomitant ingestions. Furthermore, formal abuse liability studies do not support high abuse propensity for GHB, mainly because oversedation and dizziness may lead most individuals to find GHB unpleasant at high doses. As supported by 2 large studies, there is limited evidence to suggest widespread use as an agent in sexual assault. Years of clinical use in narcolepsy do not support the development of tolerance or withdrawal in those subjects without substance dependence.

CONCLUSIONS

Tolerability and abuse liability issues, while a concern with GHB given its abuse potential, do not preclude further study of the potential use for insomnia in nondually diagnosed schizophrenia. Full cognizance must be taken of risk/benefit tradeoffs, and to the development of improved formulations with decreased abuse liability.

Incidence of craving for and abuse of gamma-hydroxybutyric acid (GHB) in different populations of treated alcoholics: an open comparative study

Gamma-hydroxybutyric acid (GHB) is a drug currently used for the treatment of alcohol dependence. The aim of our study was to investigate the incidence of craving for and abuse of GHB in 47 patients enrolled and divided into four groups: group A (pure alcoholics), group B (alcoholics with a sustained full remission from cocaine dependence), group C (alcoholics with a sustained full remission from heroin dependence) and group D (alcoholics in a methadone maintenance treatment [MMT] programme). All patients were treated with an oral dose of GHB (50 mg/kg of body weight t.i.d.) for three months. Craving for GHB was statistically significant higher in group B than in group A (P < 0.001), C (P = 0.01) and D (P < 0.001), and in group C than in group D (P < 0.05). Abuse of GHB proved to be statistically significant higher in group B than in group A (P < 0.001) and D (P < 0.01), and in group C than in group A (P = 0.01) and D (P < 0.05). Thus, the administration of GHB in alcoholics with a sustained full remission from heroin or cocaine dependence is not recommended; however, this should not discourage physicians from using GHB for the treatment of pure alcoholics or alcohol dependents following a MMT.

Gamma-Hydroxybutyrate Reduces both Withdrawal Syndrome and Hypercortisolism in Severe Abstinent Alcoholics: An Open Study vs. Diazepam

In 42 alcoholic inpatients we performed an open randomized study to compare the effects of diazepam and gamma-hydroxybutyrate (GHB) on the suppression of severe alcohol withdrawal syndrome and hypercortisolism. Both diazepam (.5 mg/kg bodyweight, q.i.d.) and GHB (50 mg/kg bodyweight, q.i.d.) were orally administered for three weeks. During all study period, GHB was more able than diazepam in reducing both withdrawal syndrome and hypercortisolism. These effects were evident during the first week of treatment and persisted throughout the study period. The results confirm a strict correlation between high levels of plasma cortisol and alcohol withdrawal symptoms and they show a slight superiority of GHB over diazepam in the suppression of both ethanol withdrawal and hypercortisolism. Taken together, our data suggest that GHB may act as potent anti-withdrawal agent in severe abstinent alcoholics.

Gamma hydroxybutyric acid (GHB) for the treatment of alcohol dependence: a review

Gamma-hydroxybutyric acid (GHB) is a short-chain fatty acid structurally similar to the inhibitory neurotransmitter gamma-aminobutyric acid. Clinical trials have demonstrated that 50-100 mg/kg of GHB fractioned into three or six daily doses is able to suppress alcohol withdrawal symptoms and facilitates the maintenance of abstinence from alcohol. These studies have also shown that GHB craving episodes are a very limited phenomenon (about 10-15%). Thus, physicians with access should consider the clinical efficacy of GHB as a valid pharmacological tool for the treatment of alcohol addiction.

Pharmacological doses of gamma-hydroxybutyrate (GHB) potentiate histone acetylation in the rat brain by histone deacetylase inhibition

Several small chain fatty acids, including butyrate, valproate, phenylbutyrate and its derivatives, inhibit several HDAC activities in the brain at a several hundred micromolar concentration. Gamma-hydroxy-butyrate (GHB), a natural compound found in the brain originating from the metabolism of GABA, is structurally related to these fatty acids. The average physiological tissue concentration of GHB in the brain is below 50 microM, but when GHB is administered or absorbed for therapeutic or recreative purposes, its concentration reaches several hundred micromolars. In the present scenario, we demonstrate that pharmacological concentrations of GHB significantly induce brain histone H3 acetylation with a heterogeneous distribution in the brain and reduce in vitro HDAC activity. The degree of HDAC inhibition was also different according to the region of the brain considered. Taking into account the multiple physiological and functional roles attributed to the modification of histone acetylation and its consequences at the level of gene expression, we propose that part of the therapeutic or toxic effects of high concentrations of GHB in the brain after therapeutic administration of the drug could be partly due to GHB-induced epigenetic factors. In addition, we hypothesize that GHB, being naturally synthesized in the cytosolic compartment of certain neurons, could penetrate into the nuclei and may reach sufficient levels that could significantly modulate histone acetylation and may participate in the epigenetic modification of gene expression.

Behavioral analyses of GHB: receptor mechanisms

GHB is used therapeutically and recreationally, although the precise mechanism of action responsible for its different behavioral effects is not entirely clear. The purpose of this review is to summarize how behavioral procedures, especially drug discrimination procedures, have been used to study the mechanism of action of GHB. More specifically, we will review several different drug discrimination procedures and discuss how they have been used to qualitatively and quantitatively study different components of the complex mechanism of action of GHB. A growing number of studies have provided evidence that the behavioral effects of GHB are mediated predominantly by GABAB receptors. However, there is also evidence that the mechanisms mediating the effects of GHB and the prototypical GABAB receptor agonist baclofen are not identical, and that other mechanisms such as GHB receptors and subtypes of GABAA and GABAB receptors might contribute to the effects of GHB. These findings are consistent with the different behavioral profile, abuse liability, and therapeutic indications of GHB and baclofen. A better understanding of the similarities and differences between GHB and baclofen, as well as the pharmacological mechanisms of action underlying the recreational and therapeutic effects of GHB, could lead to more effective medications with fewer adverse effects.

Gamma-hydroxybutyric acid in male and female cynomolgus monkeys trained to discriminate 1.0 or 2.0 g/kg ethanol

Gamma-hydroxybutyric acid has been proposed as a pharmacotherapy for alcoholism in part based on similar discriminative stimulus effects as ethanol. To date, drug discrimination studies with gamma-hydroxybutyric acid and ethanol have exclusively used rodents or pigeons as subjects. To evaluate possible differences between species, sex, and route of administration, this study investigated the substitution of gamma-hydroxybutyric acid (intragastrically or intramuscularly) for ethanol 30 or 60 min after administration in male (n=6) and female (n=7) cynomolgus monkeys trained to discriminate 1.0 and 2.0 g/kg ethanol. At least one dose of gamma-hydroxybutyric acid completely or partially substituted for ethanol in three of the 13 monkeys tested, with each case occurring in female monkeys. Ethanol-appropriate responding did not increase with gamma-hydroxybutyric acid dose. Monkeys were more sensitive to the response rate decreasing effects of gamma-hydroxybutyric acid administered intramuscularly compared with intragastrically. The lack of gamma-hydroxybutyric acid substitution for ethanol suggests that these drugs have different receptor bases for discrimination. Furthermore, the data do not strongly support shared discriminative stimulus effects as the rationale for gamma-hydroxybutyric acid pharmacotherapy for alcoholism.

gamma-Hydroxybutyric acid (GHB) suppresses alcohol's motivational properties in alcohol-preferring rats

gamma-Hydroxybutyric acid (GHB) reduces alcohol drinking, promotes abstinence from alcohol, suppresses craving for alcohol, and ameliorates alcohol withdrawal syndrome in alcoholics. At preclinical level, GHB suppresses alcohol withdrawal signs and alcohol intake in rats. The present study was designed to investigate whether GHB administration was capable of affecting alcohol's motivational properties (the possible animal correlate of human craving for alcohol) in selectively bred Sardinian alcohol-preferring rats. To this aim, rats were initially trained to lever press for alcohol (15%, vol/vol) under a procedure of operant, oral alcohol self-administration (fixed ratio 4 in 30-min daily sessions). Once responding for alcohol had stabilized, rats were divided into two groups and allocated to two independent experiments. Experiment 1 assessed the effect of GHB (0, 25, 50, and 100mg/kg, i.p.) on breakpoint for alcohol, defined as the lowest response requirement not achieved by each rat when exposed to a single-session progressive ratio schedule of reinforcement. Experiment 2 assessed the effect of GHB (0, 25, 50, and 100mg/kg, i.p.) on single-session extinction responding for alcohol (alcohol was absent and unreinforced responding was recorded). Breakpoint and extinction responding for alcohol are reliable indexes of alcohol's motivational strength. In Experiment 1, all doses of GHB reduced--by approximately 20% in comparison to saline-treated rats--breakpoint for alcohol. In Experiment 2, administration of 25, 50, and 100mg/kg GHB reduced--by approximately 25%, 40%, and 50%, respectively, in comparison to saline-treated rats--extinction responding for alcohol. Conversely, no dose of GHB altered breakpoint and extinction responding for sucrose (3%, wt/vol) in two independent subsets of Sardinian alcohol-preferring rats. Together, these data suggest that GHB administration specifically suppressed alcohol's motivational properties in Sardinian alcohol-preferring rats. These results are consistent with the anticraving properties of GHB observed in clinical studies.

Baclofen and gamma-hydroxybutyrate withdrawal

INTRODUCTION

Benzodiazepine treatment of life-threatening gamma-hydroxybutyrate (GHB) withdrawal is frequently unsatisfactory. Animal studies suggest strongly that treatment with GABA(B) agonists, such as baclofen, will be a more effective strategy.

METHODS

A case report from the medical intensive care unit (ICU) of the university tertiary care hospital.

RESULTS

A 61-year-old woman was admitted to the medical ICU for severe withdrawal symptoms from chronic GHB use. This manifested as delirium, tremor, and seizures despite only small decreases in GHB dose and treatment with benzodiazepines. The addition of baclofen allowed the rapid sequential decreases in the GHB dose without seizure or delirium and resulted in long-term improvement of her tremor.

CONCLUSIONS

Baclofen, a GABA(B) agonist, may be a useful agent in the treatment of severe GHB withdrawal.

Comparing and combining gamma-hydroxybutyric acid (GHB) and naltrexone in maintaining abstinence from alcohol: an open randomised comparative study

Maintaining abstinence from alcohol is the main goal in treating alcohol dependence. Our aim was to evaluate the efficacy of gamma-hydroxybutyric acid (GHB) and naltrexone (NTX), and their combination in maintaining abstinence. Fifty-five alcoholics were randomly enrolled in three groups and treated for 3 months with GHB, GHB plus NTX, and NTX, respectively. At the end of treatments, abstinence was maintained by 13 patients (72.2%) in combination group, 8 patients (40%; P=0.03) in GHB group, and one patient (5.9%; P=0.0001) in NTX group. Relapses in heavy drinking tended to occur more frequently in GHB group (15%) than in either combination group (no cases) or NTX group (5.9%), but such differences were not statistically significant. The GHB/NTX combination was more effective than either drug given alone; this suggests that the two drugs combine their different actions synergistically without suppressing the favourable effects of each other.

Gamma-Hydroxybutyrate (GHB), gamma-butyrolactone (GBL), and 1,4-butanediol (1,4-BD) reduce the volume of cerebral infarction in rodent transient middle cerebral artery occlusion

gamma-Hydroxybutyric acid (GHB), an endogenous organic acid catabolite of gamma-aminobutyric acid (GABA), has been shown to have tissue-protective effects in various organs, including the brain. We examined the potential neuroprotective effect of GHB and its chemical precursors, gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), in the rodent ischemic stroke model by intraluminal filament middle cerebral artery occlusion (MCAO). Adult male Sprague-Dawley rats underwent transient left-sided MCAO and received intraperitoneal treatment with 300 mg/kg of GHB, GBL, 1,4-BD, or control vehicle given at 30 min before, as well as 180 and 360 min after the onset of ischemia. Infarct volumes were determined 24 h after MCAO. In transient MCAO, the mean volume of infarction for control rats was 464.4 +/- 17.9 cu.mm versus 273.6 +/- 53.1, 233.3 +/- 44.7, and 275.4 +/- 39.9 cu.mm for rats treated with 1,4-BD (P < 0.05), GBL (P < 0.05), and GHB (P < 0.05), respectively. We conclude that GHB, GBL, and 1,4-BD protect against rat focal cerebral ischemia from transient MCAO.

Relative abuse liability of GHB in humans: A comparison of psychomotor, subjective, and cognitive effects of supratherapeutic doses of triazolam, pentobarbital, and GHB

Although preclinical studies suggest that GHB has low likelihood for abuse, case reports indicate that GHB is abused. This study evaluated the relative abuse liability of GHB in 14 volunteers with histories of drug abuse. Psychomotor, subjective, and cognitive effects of a broad range of GHB doses (2-18 g/70 kg), up to a dose that produced severe behavioral impairment in each participant, were compared to placebo and two abused sedative/hypnotic drugs, triazolam (0.5 and 1 mg/70 kg) and pentobarbital (200 and 400 mg/70 kg), under double-blind, double-dummy conditions at a residential research facility. In general, GHB produced effects similar to triazolam and pentobarbital, although GHB was not identified as a benzodiazepine or barbiturate by participants that correctly identified triazolam and pentobarbital as such. On most measures of likelihood of abuse (eg ratings of liking, reinforcing effects), effects of pentobarbital were significantly greater than those of triazolam, with GHB being intermediate. GHB produced significantly greater negative subjective effects, including nausea, than the other drugs. Memory impairment after GHB was less than that after triazolam and pentobarbital. Within participants, the dose-effect function for sedation was steeper for GHB than for triazolam and pentobarbital. Also, at higher doses, GHB was associated with greater sedation and more variability across participants in sedation. Taken together, these data suggest that the profile of effects of GHB only partially overlaps with that of triazolam and pentobarbital. Although the likelihood for GHB to be abused is intermediate to triazolam and pentobarbital, the possibility of accidental overdose (ie greater sedation than intended) with GHB appears to be greater.