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

Substitution therapy for patients with alcohol dependence: Mechanisms of action and efficacy

New approaches for the treatment of alcohol dependence (AD) may improve patient outcomes. Substitution maintenance therapy is one of the most effective treatment options for opioid and nicotine use disorders. So far, there has been little attention to substitution therapy for the treatment of AD. Here, we explain the mechanistic foundations of alcohol substitution maintenance therapy. Alcohol has many primary targets in the brain (and other organs) and the physical interaction of ethanol molecules with these specific ethanol-sensitive sites on a variety of ionotropic receptors (e.g. GABA-A, NMDA, and nicotinic acetylcholine (nACh) receptors) and ion channels provides the rationale for substitution. As such, a variety of compounds can interact with those ethanol-sensitive sites and can thus substitute for some of the effects of alcohol. For some of these compounds, alcohol discrimination studies have shown their substitution potential. Accordingly, potential substitution treatments include agonists acting at GABA receptors such as sodium oxybate, baclofen and benzodiazepines, NMDA receptor antagonists such as ketamine and memantine, or nAChRs agonists such as varenicline. All these compounds are already approved for other indications and we present clinical evidence for these drugs in the treatment of alcohol withdrawal syndrome (AWS) and in the long-term treatment of AD, and outline future steps for their acceptance as substitution treatment in AD. Finally, we discuss the substitution approach of managed alcohol programs for the most severely affected homeless populations. Results showed that sodium oxybate is probably the closest to a substitution therapy for AD and is already approved for the treatment of AWS and in the long-term treatment of AD in some countries. In conclusion, we argue that better AD treatment can be provided if substitution maintenance treatments for alcohol are implemented at a similar scale as for opioid and nicotine use disorder.

Interaction between γ-Hydroxybutyric Acid and Ethanol: A Review from Toxicokinetic and Toxicodynamic Perspectives

Gamma-hydroxybutyric acid (GHB) is a potent, short-acting central nervous system depressant as well as an inhibitory neurotransmitter or neuromodulator derived from gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter. The sodium salt of GHB, sodium oxybate, has been used for the treatment of narcolepsy and cataplexy, whereas GHB was termed as a date rape drug or a club drug in the 1990s. Ethanol is the most co-ingested drug in acute GHB intoxication. In this review, the latest findings on the combined effects of GHB and ethanol are summarized from toxicokinetic and toxicodynamic perspectives. For this purpose, we mainly discussed the pharmacology and toxicology of GHB, GHB intoxication under alcohol consumption, clinical cases of the combined intoxication of GHB and ethanol, and previous studies on the toxicokinetic and toxicodynamic interactions between GHB and ethanol in humans, animals, and an in vitro model. The combined administration of GHB and ethanol enhanced sedation and cardiovascular dysfunction, probably by the additive action of GABA receptors, while toxicokinetic changes of GHB were not significant. The findings of this review will contribute to clinical and forensic interpretation related to GHB intoxication. Furthermore, this review highlights the significance of studies aiming to further understand the enhanced inhibitory effects of GHB induced by the co-ingestion of ethanol.

Cognitive Impairment Following Clinical or Recreational Use of Gammahydroxybutyric Acid (GHB): A Systematic Review

BACKGROUND

GHB (gamma-hydroxybutyric acid; sodium oxybate) is a general anaesthetic that is clinically used for the treatment of narcolepsy, cataplexy, alcohol withdrawal and alcohol relapse prevention. In addition, GHB is recreationally used. Most clinical and recreational users regard GHB as an innocent drug devoid of adverse effects, despite its high dependence potential and possible neurotoxic effects. At high doses, GHB may lead to a comatose state. This paper systematically reviews possible cognitive impairments due to clinical and recreational GHB use.

METHODS

PubMed and PsychINFO were searched for literature data about the acute and residual cognitive deficits following GHB use. This review is conducted using the PRISMA protocol.

RESULTS

A total of 43 reports covering human and animal data on GHB-induced cognitive impairments were eligible and reviewed. This systematic review found no indication for cognitive impairments after clinical GHB use. However, it supports the view that moderate GHB use may result in acute short-term cognitive impairments, whereas regular high-dose GHB use and/or multiple GHB-induced comas are probably neurotoxic resulting in long-term residual cognitive impairments.

CONCLUSION

These results emphasize the need for awareness among clinicians and recreational users to minimize negative health consequences of recreational GHB use, particularly when high doses are used and GHB-induced comas occur.

The recognition and management of protracted alcohol withdrawal may improve and modulate the pharmacological treatment of alcohol use disorder

About 50% of persons with an alcohol use disorder may have symptoms of alcohol withdrawal syndrome (AWS) when they reduce or discontinue their alcohol consumption. Protracted alcohol withdrawal (PAW), an underestimated and not yet clearly defined clinical condition that follows the acute stage of AWS, is characterized by the presence of substance-specific signs and symptoms (i.e. anxiety, irritability, mood instability, insomnia, craving) common to acute AWS, but persisting beyond the generally expected acute AWS time frames. Considering that PAW symptoms are mainly related to the neuro-adaptive changes of gamma-aminobutyric acid (GABA) and N-methyl-d-aspartate (NMDA) systems, naltrexone, nalmefene, and disulfiram may not be able to suppress the symptoms of PAW. After treatment of the acute phase of AWS, a more specifically pharmacological therapy able to suppress PAW symptoms could perhaps be used earlier and may be more helpful in preventing the risk of alcohol relapse, which remains higher during the first months of treatment. In light of this, medications acting on GABA and NMDA neurotransmitter systems to counterbalance the up-regulation of NMDA and the down-regulation of GABA could be employed in combination and started as soon as possible.

Diagnosis and treatment of acute alcohol intoxication and alcohol withdrawal syndrome: position paper of the Italian Society on Alcohol

The chronic use of alcohol can lead to the onset of an alcohol use disorder (AUD). About 50% of subjects with an AUD may develop alcohol withdrawal syndrome (AWS) when they reduce or discontinue their alcohol consumption and, in 3-5% of them, convulsions and delirium tremens (DTs), representing life-threatening complications, may occur. Unfortunately, few physicians are adequately trained in identifying and treating AWS. The Italian Society on Alcohol has, therefore, implemented a task force of specialists to draw up recommendations for the treatment of AWS with the following main results: (1) while mild AWS may not require treatment, moderate and severe AWS need to be pharmacologically treated; (2) out-patient treatment is appropriate in patients with mild or moderate AWS, while patients with severe AWS need to be treated as in-patients; (3) benzodiazepines, BDZs are the "gold standard" for the treatment of AWS and DTs; (4) alpha-2-agonists, beta-blockers, and neuroleptics may be used in association when BDZs do not completely resolve specific persisting symptoms of AWS; (5) in the case of a refractory form of DTs, the use of anaesthetic drugs (propofol and phenobarbital) in an intensive care unit is appropriate; (6) alternatively to BDZs, sodium oxybate, clomethiazole, and tiapride approved in some European Countries for the treatment of AWS may be employed for the treatment of moderate AWS; (7) anti-convulsants are not sufficient to suppress AWS, and they may be used only in association with BDZs for the treatment of refractory forms of convulsions in the course of AWS.

Drug-drug interactions in the treatment for alcohol use disorders: A comprehensive review

Drug interactions are one of the most common causes of side effects in polypharmacy. Alcoholics are a category of patients at high risk of pharmacological interactions, due to the presence of comorbidities, the concomitant intake of several medications and the pharmacokinetic and pharmacodynamic interferences of ethanol. However, the data available on this issue are limited. These reasons often frighten clinicians when prescribing appropriate pharmacological therapies for alcohol use disorder (AUD), where less than 15% of patients receive an appropriate treatment in the most severe forms. The data available in literature regarding the relevant drug-drug interactions of the medications currently approved in United States and in some European countries for the treatment of AUD (benzodiazepines, acamprosate, baclofen, disulfiram, nalmefene, naltrexone and sodium oxybate) are reviewed here. The class of benzodiazepines and disulfiram are involved in numerous pharmacological interactions, while they are not conspicuous for acamprosate. The other drugs are relatively safe for pharmacological interactions, excluding the opioid withdrawal syndrome caused by the combination of nalmefene or naltrexone with an opiate medication. The information obtained is designed to help clinicians in understanding and managing the pharmacological interactions in AUDs, especially in patients under multi-drug treatment, in order to reduce the risk of a negative interaction and to improve the treatment outcomes.

Sodium oxybate plus nalmefene for the treatment of alcohol use disorder: A case series

The treatment of alcohol use disorder still remains a challenge. The efficacy of the combined pharmacological treatment for alcohol use disorder has been widely investigated with controversial results. The aim of our case series was to investigate the effect of nalmefene in patients not responding to sodium oxybate therapy. We describe seven cases of consecutive patients affected by alcohol use disorder, and treated with sodium oxybate (50 mg/kg per day) who did not achieve complete alcohol abstinence after at least one month of pharmacological treatment. Then, in partial- and non-responder patients to sodium oxybate treatment, administration of nalmefene, 18 mg as needed, was commenced. Our data show that, during the first month of the combined treatment of sodium oxybate plus nalmefene, patients were able to achieve alcohol abstinence (two patients), to suppress (five cases) or reduce (two patients) episodes of heavy drinking days, and to suppress the onset of craving for sodium oxybate (one patient). Likely, nalmefene may act in modulating the excessive reward effect of sodium oxybate, which may be responsible for the persistence of alcohol intake and for the onset of craving for sodium oxybate. However, controlled clinical trials to confirm the safety and efficacy of sodium oxybate plus nalmefene in treating alcohol use disorder are warranted.

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.

The behavioural profile of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol in humans

Gamma-hydroxybutyrate (GHB) is a putative neurotransmitter, a drug of abuse, and a medical treatment for narcolepsy and other neuropsychiatric disorders. Its precursors gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) are endogenously converted to GHB and thereby exert their psychobehavioural effects. In humans, GHB has a wide spectrum of properties ranging from stimulation and euphoria in lower doses, to sedation, deep sleep, and coma after ingestion of high doses. However, behavioural studies in healthy volunteers remain scarce and are usually limited to psychomotor performance testing. Most available data arise from either qualitative studies with illicit users or clinical trials examining therapeutic properties of GHB (then usually termed sodium oxybate). Here, we present an overview of the behavioural effects of GHB, GBL, and 1,4-BD in these three populations. GHB and its precursors strongly influence behaviours related to core human autonomic functions such as control of food intake, sexual behaviour, and sleep-wake regulation. These effects are instrumentalised by illicit users and clinically utilised in neuropsychiatric disorders such as narcolepsy, fibromyalgia, and binge-eating syndrome. Considering the industry withdrawal from psychopharmacology development, repurposing of drugs according to their behavioural and clinical profiles has gained increasing relevance. As such, GHB seems to be an attractive candidate as an experimental therapeutic in depression.

Mechanisms for the Specific Properties of γ-Hydroxybutyrate in Brain

γ-Hydroxybutyrate (GHB) is both a natural brain compound with neuromodulatory properties at central GABAergic synapses (micromolar concentration range) and also a drug (Xyrem(R) ) clinically used for the treatment of various neurological symptoms (millimolar dose range). However, this drug has abuse potential and can be addictive for some patients. Here, we review the basic mechanistic role of endogenous GHB in brain as well as the properties and mechanisms of action for therapeutic clinical doses of exogenous GHB. Several hypotheses are discussed with a preference for a molecular mechanism that conciliates most of the findings available. This conciliatory model may help for the design of GHB-like drugs active at lower doses and devoid of major side effects.