Gamma-hydroxybutyrate and ethanol effects and interactions in humans

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.

The prevalence of selected licit and illicit drugs in drug facilitated sexual assaults

Little is known about the prevalence of incapacitating substances present in drug facilitated sexual assaults (DFSA). Presented here is a literature review conducted to provide background information, such as symptoms, exacerbations, and drug interactions, on drugs typically implicated in DFSA, namely gamma-hydroxybutyrate (GHB), gamma-butyrolactone (GBL), 1,4-butanediol (1,4-BD), ketamine, diazepam, oxycodone, methamphetamine, and alcohol. Literature found through Scopus and Pubmed was reviewed to determine the current prevalence of these substances in DFSA with a focus on Australian data. The global literature revealed that there is a wide variety of substances used in DFSA and the prevalence varied by country. For example, it was found that in Northern Ireland, opioids were most prevalent whereas in France, benzodiazepines were most prevalent. In Australia the review revealed a lack of contemporary data with the most recent report in Victoria using data collected during 2011-2013. The literature also revealed there can be an important difference between self-reported substance use and substances discovered via toxicological analysis. This can be due to the challenges of biological detection, reliability of self-reporting, and the possibility of a substance being introduced to a person's food or drink without their knowledge. This review highlights the need for the collection and analysis of current data pertaining to DFSA reports and the drugs detected, and due to the constantly evolving picture of both licit and illicit drug use an assessment of the role of prescription medications in DFSA due to drug-drug interactions as well as potential to incapacitate is warranted.

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.

Ethanol inhibits dopamine uptake via organic cation transporter 3: Implications for ethanol and cocaine co-abuse

Concurrent cocaine and alcohol use is among the most frequent drug combination, and among the most dangerous in terms of deleterious outcomes. Cocaine increases extracellular monoamines by blocking dopamine (DA), norepinephrine (NE) and serotonin (5-HT) transporters (DAT, NET and SERT, respectively). Likewise, ethanol also increases extracellular monoamines, however evidence suggests that ethanol does so independently of DAT, NET and SERT. Organic cation transporter 3 (OCT3) is an emergent key player in the regulation of monoamine signaling. Using a battery of in vitro, in vivo electrochemical, and behavioral approaches, as well as wild-type and constitutive OCT3 knockout mice, we show that ethanol's actions to inhibit monoamine uptake are dependent on OCT3. These findings provide a novel mechanistic basis whereby ethanol enhances the neurochemical and behavioral effects of cocaine and encourage further research into OCT3 as a target for therapeutic intervention in the treatment of ethanol and ethanol/cocaine use disorders.

Gamma-hydroxybutyrate (GHB), 1,4-butanediol (1,4BD), and gamma-butyrolactone (GBL) intoxication: A state-of-the-art review

γ-hydroxybutyrate (GHB) is synthesized endogenously from γ-aminobutyric acid (GABA) or exogenously from 1,4-butanediol (butane-1,4-diol; 1,4-BD) or γ-butyrolactone (GBL). GBL, and 1,4-BD are rapidly converted to GHB. The gastric absorption time, volume of distribution, and half-life of GHB are between 5 and 45 min, 0.49 ± 0.9 L/kg, and between 20 and 60 min, respectively. GHB and its analogues have a dose-dependent effect on the activation of GHB receptor, GABA-B, and GABA localized to the central nervous system. After ingestion, most patients present transient neurological disorders (lethal dose: 60 mg/kg). Chronic GHB consumption is associated with disorders of use and a withdrawal syndrome when the consumption is discontinued. GHB, GBL, and 1,4-BD are classified as narcotics but only the use of GHB is controlled internationally. They are used for drug facilitated (sexual) assault, recreational purposes, slamsex, and chemsex. To confirm an exogenous intake or administration of GHB, GBL, or 1-4-BD, the pre-analytical conservation is crucial. The antemortem cutoff doses for detection are 5 and 5-15 mg/L, with detection windows of 6 and 10 h in the blood and urine, respectively Control of GHB is essential to limit the number of users, abuse, associated risks, and death related to their consumption.

Alcohol perturbed locomotor behavior, metabolism, and pharmacokinetics of gamma-hydroxybutyric acid in rats

Gamma-hydroxybutyric acid (GHB), both a metabolic precursor and product of gamma-aminobutyric acid (GABA), is a central nervous system depressant used for the treatment of narcolepsy-associated cataplexy and alcohol withdrawal. However, administration of GHB with alcohol (ethanol) is a major cause of hospitalizations related to GHB intoxication. In this study, we investigated locomotor behavior as well as metabolic and pharmacokinetic interactions following co-administration of GHB and ethanol in rats. The locomotor behavior of rats was evaluated following the intraperitoneal administration of GHB (sodium salt, 500 mg/kg) and/or ethanol (2 g/kg). Further, time-course urinary metabolic profiling of GHB and its biomarker metabolites glutamic acid, GABA, succinic acid, 2,4-dihydroxybutyric acid (OH-BA), 3,4-OH-BA, and glycolic acid as well as pharmacokinetic analysis were performed. GHB/ethanol co-administration significantly reduced locomotor activity, compared to the individual administration of GHB or ethanol. The urinary and plasma concentrations of GHB and other target compounds, except for 2,4-OH-BA, were significantly higher in the GHB/ethanol co-administration group than the group administered only GHB. The pharmacokinetic analysis results showed that the co-administration of GHB and ethanol significantly increased the half-life of GHB while the total clearance decreased. Moreover, a comparison of the metabolite-to-parent drug area under the curve ratios demonstrated that the metabolic pathways of GHB, such α- and β-oxidation, were inhibited by ethanol. Consequently, the co-administration of GHB and ethanol aggravated the metabolism and elimination of GHB and enhanced its sedative effect. These findings will contribute to clinical interpretation of GHB intoxication.

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.

A phase 1 study to assess potential interaction between ASP8062 and alcohol in healthy adult subjects

BACKGROUND

ASP8062 is a novel orally active GABA_B receptor positive allosteric modulator in clinical development for the treatment of alcohol use disorder (AUD) and opioid use disorder (OUD).

AIMS

This study assessed the potential pharmacokinetic/pharmacodynamic interaction between ASP8062 and alcohol under single-dose conditions in healthy adults.

METHODS

A double-blind, placebo-controlled, crossover phase 1 study was conducted in which 20 subjects were randomly assigned to four treatment sequences (ASP8062 + alcohol; ASP8062 + placebo alcohol; placebo + alcohol; placebo + placebo alcohol) each consisting of four treatment periods, separated by washout periods of at least 14 days. An analysis of variance was used to assess pharmacokinetic interaction and a mixed-effects analysis of covariance was used to assess pharmacodynamic interaction.

RESULTS/OUTCOMES

After administration of alcohol, a mild to minimal increase in plasma exposure (AUC_inf and C_max) of ASP8062 was observed, but t_max and t_½ for ASP8062 remained unchanged after administration of alcohol. In contrast, ASP8062 did not affect the AUC_last and C_max of ethanol. No clinically relevant differences in cognition measurements were observed with ASP8062 compared with placebo, but there were expected impairments in psychomotor and executive function with alcohol alone. ASP8062 in combination with alcohol resulted in worse scores in cognition measurements than alcohol alone, but this potentiation was not consistent. ASP8062 administered alone was safe and well-tolerated and safety findings in subjects administered alcohol alone were not augmented when ASP8062 was administered in combination with alcohol.

CONCLUSION/INTERPRETATION

The data support further clinical studies investigating ASP8062 in patients with AUD.

Clinical effect of ethanol co-use in patients with acute drug toxicity involving the use of central nervous system depressant recreational drugs

BACKGROUND AND IMPORTANCE

Patients who use recreational drugs frequently co-ingest ethanol, which is considered a central nervous system (CNS) depressant. The clinical relevance of this in acute toxicity involving other CNS depressants is not well described.

OBJECTIVE

To assess the clinical impact of ethanol co-use in patients presenting to the emergency department (ED) with acute toxicity involving the use of CNS depressant drugs.

DESIGN, SETTINGS AND PARTICIPANTS

A retrospective multicentre study using data from the Euro-DEN Plus database from January 2014 to December 2019.

OUTCOMES MEASURE AND ANALYSIS

Comparison of epidemiologic and clinical characteristics, ED and hospital management of patients with CNS depressant intoxication with or without ethanol co-use.

MAIN RESULTS

Although 7644 (17.5%) of the 43 633 presentations were included, ethanol was co-ingested in 3811 (49.9%). In total 53.3% required medical treatment, 14 patients died. Patients with ethanol co-use more frequently presented with a Glasgow Coma Scale (GCS) ≤8 (34.1% vs. 22.4%; P  < 0.001), vomiting (8.1% vs. 4.6%; P  < 0.001), anxiety (12 % vs. 6.4%; P  < 0.001), agitation/aggression (22% vs. 14.7%; P  < 0.001), seizures (3.8% vs. 2.4%; P  < 0.001) and hypotension (7.5% vs. 4.6%; P  < 0.001). They more often required ambulance transport (85.5% vs. 76.5%; P  < 0.001), medical treatment (57.3% vs. 48.0%; P  < 0.001), hospitalization (27.7% vs. 18.9%; P  < 0.001), and admission to intensive care (12.2% vs. 4.0%; P  < 0.001). Subgroup analysis showed that GCS ≤8 was particularly common in patients who combined ethanol with opioids or gamma-hydroxybutyrate (GHB)/gamma-butyrolactone (GBL).

CONCLUSION

Co-use of ethanol with CNS-depressant drugs appears to increase the risk of adverse effects and is associated with a higher need for medical treatment, especially when ethanol is combined with opioids or GHB/GBL.

Characteristics and dose-effect relationship of clinical gamma-hydroxybutyrate intoxication: A case series

Gamma-Hydroxybutyrate (GHB) overdoses cause respiratory depression, coma, or even death. Symptoms and severity of poisoning depend on blood-concentrations and individual factors such as tolerance. A retrospective case study was conducted, evaluating GHB intoxication cases. GHB-concentrations in blood and urine were determined by gas chromatography-mass spectrometry (GC-MS) along with, in part, via enzymatic assay. GHB-concentrations, demographic data, and additional drug use, as well as specific clinical information, were evaluated. The correlation between GHB-levels in blood and associated symptoms were examined. In total, 75 cases originating from the Emergency Departments (EDs) of Hamburg and surrounding hospitals were included. Fifty-four of the patients (72%) were male. The mean GHB-concentration in blood was 248 mg/L (range 21.5-1418 mg/L). Out of the group with detailed clinical information (n = 18), the comatose group (n = 10/18) showed a mean of 244 mg/L (range 136-403 mg/L), which was higher than that of the somnolent and awake patients. Of the comatose collective, 70% (n = 7) showed co-use of one or more substances, with the additional use of cocaine being the most frequently detected (n = 5). In conclusion, a moderate dose-effect relationship was observed, although, there was some overlap in dosage concentration levels of GHB in awake and comatose patients. In GHB-intoxication cases, co-use was common as were clinical effects such as acidosis, hypotension, and impact on the heart rate. Timely analytical determination of the GHB-concentration in blood could support correct diagnosis of the cause of unconsciousness.

Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank

There are many nonopioid central nervous system depressant substances that share a gamma-aminobutyric acid (GABA) receptor-related mechanism of action. These sedatives-hypnotics can be indicated to treat anxiety, seizures, depression, and insomnia but are also used as substances of abuse and used to facilitate sexual assault. Barbiturates, methaqualone, and glutethimide were among the first type A GABA receptor-mediated sedative-hypnotics. Their clinical use was limited for most indications by serious adverse events and strong abuse potential but continue to be used illicitly around the world. The benzodiazepines supplanted barbiturates for most indications because they were less likely to cause severe adverse events in monotherapy. Flunitrazepam is a newer benzodiazepine that is preferentially used recreationally and to facilitate sexual assault. Flunitrazepam has greater potency and higher affinity for the type A GABA receptor than most benzodiazepines. Gamma-hydroxybutyric acid is sought illicitly for its hypnotic, euphoric and anabolic effects as well as to facilitate sexual assault. When any of these GABAergic drugs are used in high doses or with other sedative hypnotic agents, respiratory depression, coma, and death have occurred. Chronic use of these GABAergic drugs can lead to significant withdrawal syndromes. Phenibut and selank are poorly studied Russian drugs with GABAergic mechanisms that are inexplicably sold to US consumers as dietary supplements. Poison control center calls regarding phenibut have increased substantially over the past 5 years. Desired euphoriant effects account for the recreational and illicit use of many GABA-modulating agents. However, illicit use can lead to significant toxicities related to abuse, dependence, and subsequent withdrawal syndromes. Significant evaluation of developing agents with GABA properties should be conducted to determine abuse potential before public access ensues.

γ-Hydroxybutyric Acid-Ethanol Drug-Drug Interaction: Reversal of Toxicity with Monocarboxylate Transporter 1 Inhibitors

The drug of abuse, γ-hydroxybutyric acid (GHB), is commonly co-ingested with ethanol, resulting in a high incidence of toxicity and death. Our laboratory has previously reported that GHB is a substrate for the monocarboxylate transporters (MCTs), necessary for its absorption, renal clearance, and tissue distribution, including across the blood-brain barrier. Our goal was to investigate the drug-drug interaction (DDI) between GHB and ethanol and to evaluate MCT1 inhibition as a strategy to reverse toxicity. The toxicokinetics of this DDI were investigated, including brain-to-plasma concentration ratios, in the presence and absence of ethanol. The toxicodynamic parameters examined were respiratory depression (breathing frequency, tidal volume) and sedation (time of return-of-righting reflex). Ethanol was administered (2 g/kg i.v.) 5 minutes before the intravenous or oral administration of GHB, and MCT1 inhibitors AZD-3965 and AR-C155858 (5 mg/kg i.v.) were administered 60 minutes after GHB administration. Ethanol administration did not alter the toxicokinetics or respiratory depression caused by GHB after intravenous or oral administration; however, it significantly increased the sedation effect, measured by return-to-righting time. AZD-3965 or AR-C155858 significantly decreased the effects of the co-administration of GHB and ethanol on respiratory depression and sedation of this DDI and decreased brain concentrations and the brain-to-plasma concentration ratio of GHB. The results indicate that ethanol co-administered with GHB increases toxicity and that MCT1 inhibition is effective in reversing toxicity by inhibiting GHB brain uptake when given after GHB-ethanol administration. SIGNIFICANCE STATEMENT: These studies investigated the enhanced toxicity observed clinically when γ-hydroxybutyric acid (GHB) is co-ingested with alcohol and evaluated strategies to reverse this toxicity. The effects of the novel monocarboxylate transporter 1 (MCT1) inhibitors AR-C155858 and AZD-3965 on this drug-drug interaction have not been studied before, and these preclinical studies indicate that MCT1 inhibitors can decrease brain concentrations of GHB by inhibiting brain uptake, even when administered at times after GHB-ethanol. AZD-3965 represents a potential treatment strategy for GHB-ethanol overdoses.

γ-Hydroxybutyric Acid: Pharmacokinetics, Pharmacodynamics, and Toxicology

Gamma-hydroxybutyrate (GHB) is a short-chain fatty acid present endogenously in the brain and used therapeutically for the treatment of narcolepsy, as sodium oxybate, and for alcohol abuse/withdrawal. GHB is better known however as a drug of abuse and is commonly referred to as the "date-rape drug"; current use in popular culture includes recreational "chemsex," due to its properties of euphoria, loss of inhibition, amnesia, and drowsiness. Due to the steep concentration-effect curve for GHB, overdoses occur commonly and symptoms include sedation, respiratory depression, coma, and death. GHB binds to both GHB and GABAB receptors in the brain, with pharmacological/toxicological effects mainly due to GABAB agonist effects. The pharmacokinetics of GHB are complex and include nonlinear absorption, metabolism, tissue uptake, and renal elimination processes. GHB is a substrate for monocarboxylate transporters, including both sodium-dependent transporters (SMCT1, 2; SLC5A8; SLC5A12) and proton-dependent transporters (MCT1-4; SLC16A1, 7, 8, and 3), which represent significant determinants of absorption, renal reabsorption, and brain and tissue uptake. This review will provide current information of the pharmacology, therapeutic effects, and pharmacokinetics/pharmacodynamics of GHB, as well as therapeutic strategies for the treatment of overdoses. Graphical abstract.

Rate of elimination of γ-hydroxybutyrate from blood determined by analysis of two consecutive samples from apprehended drivers in Norway

AIM

Gamma-hydroxybutyrate (GHB) is a common drug of abuse with an elimination half-life of 20-45 min. However, there is some evidence that GHB might exhibit saturation kinetics after ingesting high recreational doses. The aim of this study was to investigate the elimination kinetics of GHB from blood in people apprehended by the police for impaired driving and secondary to describe concentrations in all GHB-positive drivers.

METHODS

Two consecutive blood samples were taken about 30-40 min apart from N = 16 apprehended drivers in Norway. GHB was determined in blood by an Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method. The changes in GHB between the two consecutive blood samples allowed estimating GHB's elimination half-life, assuming first-order and zero-order elimination kinetics. GHB concentrations are also reported for N = 1276 apprehended drivers with GHB in blood.

RESULTS

The median time interval between collecting the two blood samples was 36 min (range 20-56 min). The median concentration of GHB in the first blood sample was 56.5 mg/L (range 14.1-142 mg/L) compared with 47.8 mg/L in the second sample (range 9.75-113 mg/L). The median elimination half-life was 103 min (range 21-187 min), and GHB's median zero-order elimination rate constant was 21.0 mg/L/h (range 6.71-45.4 mg/L/h). Back-calculation to the time of driving resulted in GHB concentrations up to 820 mg/L assuming first-order kinetics and up to 242 mg/L assuming zero-order kinetics. In all drivers (N = 1276), the median GHB concentration was 73.7 mg/L and highest was 484 mg/L.

CONCLUSION

The elimination half-life of GHB in blood samples from apprehended drivers was longer than expected compared with results of controlled dosing studies. Zero-order kinetics seems a more appropriate model for GHB when concentrations are back-calculated, and the median elimination rate was 21 mg/L/h.

Intensive sex partying with gamma-hydroxybutyrate: factors associated with using gamma-hydroxybutyrate for chemsex among Australian gay and bisexual men - results from the Flux Study

Background Gamma-hydroxybutyrate (GHB) use among gay and bisexual men (GBM) has increased in recent years. It is commonly cited as a sexual-enhancement drug. There is, however, little evidence for factors associated with GHB use or the consequences of its use among GBM.

AIM

Factors associated with GHB use, its relationship to sexual risk behaviour, and the contexts, consequences, and motivations for its use were examined.

METHODS

The Following Lives Undergoing Change (Flux) Study is an online prospective observational study of Australian GBM. At baseline, a total of 3190 GBM provided details about their use of GHB. Data on frequency, methods, pleasures and consequences of their drug use, alongside key demographic variables were collected.

RESULTS

Mean age was 35.0 years. One in five men (19.5%) had a history of GHB use and 5.4% reported use within the past 6 months, with 2.7% having used it monthly or more frequently. Overdose had been experienced by 14.7%, this was more common among men who used GHB at least monthly. Being HIV-positive, having more gay friends, greater social engagement with gay men who use drugs, a greater number of sexual partners, group sex, and condomless anal intercourse with casual partners were independently associated with GHB use in the past 6 months. Greater social engagement with gay men who use drugs and group sex were independently associated with at least monthly use. More frequent GHB use was independently associated with experiencing overdose among GHB users.

CONCLUSION

Most men used GHB infrequently and it was often used explicitly to enhance sexual experiences, often in the context of intensive sex partying. Men who used GHB frequently, were at greater risk of overdose and other negative health outcomes. GHB use should be considered alongside other drugs that have been implicated in sexual risk behaviour and HIV transmission. Harm-reduction interventions need to consider the particular impact of frequent GHB use.

[Knockout Drugs: Diagnostics in the Emergency Unit and Clinical Practice]

Knockout Drugs: Diagnostics in the Emergency Unit and Clinical Practice Abstract. Every now and then, physicians are challenged with date rape drugs. If there is a suspicion of substance administration, the question of involving forensic medicine is commonly raised. In obscure situations or questionable offences, however, patients may wish for an initial diagnosis in the emergency department or the private practice. The physicians are often greatly challenged by the variety of substances, the limited analytical methods and difficulties with the interpretion of results. The major goal of this article is to present diagnostic options including their limitations. An overview of frequently involved substances is provided. Particular focus will be placed on practical aspects, including questions regarding pre-analytics and health insurance coverage.

DARK Classics in Chemical Neuroscience: Gamma-Hydroxybutyrate (GHB)

Gamma-hydroxybutyrate (GHB) is a naturally occurring short-chain fatty acid that rose to prominence as a popular club drug in the 1990s. Originally developed as an anesthetic in the early 1960s, it was later sold as an over-the-counter dietary supplement before becoming a rising substance of abuse in the following decades as one of the "date rape" drugs. Despite its abuse potential, there has been a recent surge in therapeutic interest in the drug due to its clinical viability in the treatment of narcolepsy and alcohol abuse/withdrawal. Its interactions with the GABAergic framework of higher mammals has made it the prototypical example for the study of the chief inhibitory mechanism in the human central nervous system. Though relatively obscure in terms of popular culture, it has a storied history with widespread usage in therapeutic, recreational ("Chemsex"), and some disturbingly nefarious contexts. This Review aims to capture its legacy through review of the history, synthesis, pharmacology, drug metabolism, and societal impact of this DARK classic in chemical neuroscience.

Alcohol Interaction with Cocaine, Methamphetamine, Opioids, Nicotine, Cannabis, and γ-Hydroxybutyric Acid

Millions of people around the world drink alcoholic beverages to cope with the stress of modern lifestyle. Although moderate alcohol drinking may have some relaxing and euphoric effects, uncontrolled drinking exacerbates the problems associated with alcohol abuse that are exploding in quantity and intensity in the United States and around the world. Recently, mixing of alcohol with other drugs of abuse (such as opioids, cocaine, methamphetamine, nicotine, cannabis, and γ-hydroxybutyric acid) and medications has become an emerging trend, exacerbating the public health concerns. Mixing of alcohol with other drugs may additively or synergistically augment the seriousness of the adverse effects such as the withdrawal symptoms, cardiovascular disorders, liver damage, reproductive abnormalities, and behavioral abnormalities. Despite the seriousness of the situation, possible mechanisms underlying the interactions is not yet understood. This has been one of the key hindrances in developing effective treatments. Therefore, the aim of this article is to review the consequences of alcohol's interaction with other drugs and decipher the underlying mechanisms.

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.

Effect of γ-hydroxybutyrate (GHB) on driving as measured by a driving simulator

RATIONALE

Gamma-hydroxybutyrate acid (GHB), a GABA_B receptor agonist approved for treatment of narcolepsy, impairs driving ability, but little is known about doses and plasma concentrations associated with impairment and time course of recovery.

OBJECTIVE

To assess effects of oral GHB (Xyrem®) upon driving as measured by a driving simulator, and to determine plasma concentrations associated with impairment and the time course of recovery.

METHODS

Randomized, double-blind, two-arm crossover study, during which 16 participants received GHB 50 mg/kg orally or placebo. GHB blood samples were collected prior to and at 1, 3, and 6 h post dosing. Driving simulator sessions occurred immediately after blood sampling.

RESULTS

Plasma GHB was not detectable at baseline or 6 h post dosing. Median GHB concentrations at 1 and 3 h were 83.1 mg/L (range 54-110) and 24.4 mg/L (range 7.2-49.7), respectively. Compared to placebo, at 1 h post GHB dosing, significant differences were seen for the life-threatening outcome collisions (p < 0.001) and off-road accidents (p = 0.018). Although driving was not faster, there was significantly more weaving and erratic driving with GHB as measured by speed deviation (p = 0.002) and lane position deviation (p = 0.004). No significant impairment regarding driving outcomes was found in the GHB group at 3 and 6 h post dose.

CONCLUSION

GHB in doses used to treat narcolepsy resulted in severe driving impairment at 1 h post dosing. After 3 to 6 h, there was full recovery indicating that safe driving is expected the next morning after bedtime therapeutic GHB use in the absence of other substances.

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.

Impact of acute administration of sodium oxybate on heart rate variability in children with type 1 narcolepsy

BACKGROUND

Currently, cardiovascular measurements in children affected with type 1 narcolepsy (NT1) have never been investigated, and neither have their modulation by the administration of sodium oxybate (SO).

METHODS

Twelve drug-naïve NT1 children (four males, eight females) with a mean age of 11 ± 3.16 years underwent a nocturnal polysomnography, at baseline and during the first night of SO administration. Data were contrasted with those recorded in 23 age-matched healthy controls. Heart rate variability (HRV) analysis was performed by analyzing the electrocardiogram signal for automatic detection of R waves with a computer program calculating a series of standard time-domain measures and obtaining spectral parameters, by means of a Fast-Fourier Transform.

RESULTS

In sleep stages N2 and N3, NT1 children showed increased power in the low-frequency (LF) and very-LF (VLF) ranges, when compared to controls. In addition, HRV (as measured by time domain parameters) during all sleep stages tended to be slightly higher in patients when compared to controls. Treatment with SO did not change significantly any parameter, but an overall trend to mildly decreased HRV that reached a significant value only during R sleep.

CONCLUSIONS

HRV during all sleep stages tended to be slightly higher in young patients when compared to controls, confirming the presence of a slight sympathovagal system imbalance even in NT1 children. SO tends to decrease these values especially during REM sleep and in that regard, further studies supporting these preliminary findings and considering the long-term effects of SO on heart rate parameters are warranted.

Lack of Effect of Vortioxetine on the Pharmacokinetics and Pharmacodynamics of Ethanol, Diazepam, and Lithium

INTRODUCTION

Because the multimodal antidepressant vortioxetine is likely to be coadministered with other central nervous system (CNS)-active drugs, potential drug-drug interactions warrant examination.

OBJECTIVE

These studies evaluated whether there are pharmacokinetic and/or pharmacodynamic interactions between vortioxetine and ethanol, diazepam, or lithium.

METHODS

This series of phase I studies included healthy men and women (only men in the lithium study) aged 18-45 years. The ethanol study was a randomized, double-blind, two-parallel group, four-period crossover study in which subjects received a single dose of vortioxetine (20 or 40 mg) or placebo with or without ethanol, and the diazepam study was a randomized, double-blind, placebo-controlled, two-sequence, two-period crossover study in which subjects received a single dose of diazepam following multiple doses of vortioxetine 10 mg/day or placebo. These two studies evaluated the effect of coadministration on standardized psychomotor parameters and on selected pharmacokinetic parameters of each drug. The lithium study was a single-blind, single-sequence study evaluating the effect of multiple doses of vortioxetine 10 mg/day on the steady-state pharmacokinetics of lithium.

RESULTS

Concomitant administration of vortioxetine and single doses of either ethanol or diazepam had no significant effect on the psychomotor performance of subjects compared with administration of ethanol or diazepam alone. Vortioxetine had no significant effect on the pharmacokinetics of ethanol, diazepam, or lithium, and ethanol had no significant effect on the pharmacokinetics of vortioxetine.

CONCLUSIONS

Concomitant administration of these agents with vortioxetine was generally well tolerated, with no clinically relevant drug-drug pharmacokinetic or pharmacodynamic interactions identified.

GHB-involved crimes among intoxicated patients

INTRODUCTION

In recent years, the involvement of GHB in drug facilitated sexual assaults has been one of the most frequently studied aspects of GHB in both clinical and non-clinical settings. GHB-involved acquisitory crimes, however, can be mentioned as understudied research topics, as well as the poisoning severity properties of GHB.

MEASURES

The medical reports of Péterfy Sándor Street Hospital Clinic and Casualty Centre's 408 GHB-intoxication cases (352 patients) were reviewed and registered. Analyzed data consisted of epicrisis, serum and urine concentration of various substances (including GHB), scores of Glasgow Coma Scale and Poisoning Severity Score.

RESULTS

Majority of the patients were males, in their twenties. GHB was detected in 34.1% and it was solely consumed in 27.7% of all the cases. Ethanol was found to be the most frequently co-ingested substance. A higher rate of severe poisonings was observed among males. We found significant difference in the frequency of enduring sexual assaults and acquisitory crimes between intentional and unintentional GHB intake cases. Among unintentional GHB intake cases, 6.5% endured GHB-involved sexual assaults, whereas 21.7% endured an acquisitory crime. Among recurrent GHB intoxication cases generated by the same patients, voluntary and sole GHB consumptions were more frequently observed, however, enduring any crime was less characteristic.

DISCUSSION

Our results regarding demographic and substance use characteristics and the frequency of GHB-facilitated sexual assaults are in line with former findings. Enduring acquisitory crimes due to unintentional GHB intake was found to be more inherent than enduring sexual assaults. Authors emphasise that the victims of these acquisitory crimes were typically males.

CONCLUSION

GHB's role in drug facilitated acquisitory crimes seems to be significant, although the decrease in GHB's popularity is observed among intoxicated patients as well. The need for further research on GHB's impact on cognitive impairment and on sexual correlates of intentional GHB use is addressed by the authors.

Pharmacokinetics and pharmacodynamics of γ-hydroxybutyrate in healthy subjects

AIMS

γ-Hydroxybutyrate (GHB) is used as a treatment for narcolepsy and alcohol withdrawal and as a recreational substance. Nevertheless, there are limited data on the pharmacokinetics and pharmacokinetic-pharmacodynamic relationships of GHB in humans. We characterized the pharmacokinetic profile and exposure-psychotropic effect relationship of GHB in humans.

METHODS

Two oral doses of GHB (25 and 35 mg kg(-1) ) were administered to 32 healthy male subjects (16 for each dose) using a randomized, placebo-controlled, cross-over design.

RESULTS

Maximal concentrations of GHB were (geometric mean and 95% CI): 218 (176-270) nmol ml(-1) and 453 (374-549) nmol ml(-1) for the 25 and 35 mg kg(-1) GHB doses, respectively. The elimination half-lives (mean ± SD) were 36 ± 9 and 39 ± 7 min and the AUC∞ values (geometric mean and 95% CI) were 15 747 (12 854-19 290) and 40 113 (33 093-48 622) nmol∙min ml(-1) for the 20 and 35 mg kg(-1) GHB doses, respectively. Thus, plasma GHB exposure (AUC0-∞ ) rose disproportionally (+40%) with the higher dose. γ-Hydroxybutyrate produced mixed stimulant-sedative effects, with a dose-dependent increase in sedation and dizziness. It did not alter heart rate or blood pressure. A close relationship between plasma GHB exposure and its psychotropic effects was found, with higher GHB concentrations associated with higher subjective stimulation, sedation, and dizziness. No clockwise hysteresis was observed in the GHB concentration effect plot over time (i.e., no acute pharmacological tolerance).

CONCLUSION

Evidence was found of a nonlinear dose-exposure relationship (i.e., no dose proportionality) at moderate doses of GHB. The effects of GHB on consciousness were closely linked to its plasma exposure and exhibited no acute tolerance.

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.

GHB pharmacology and toxicology: acute intoxication, concentrations in blood and urine in forensic cases and treatment of the withdrawal syndrome

The illicit recreational drug of abuse, γ-hydroxybutyrate (GHB) is a potent central nervous system depressant and is often encountered during forensic investigations of living and deceased persons. The sodium salt of GHB is registered as a therapeutic agent (Xyrem®), approved in some countries for the treatment of narcolepsy-associated cataplexy and (Alcover®) is an adjuvant medication for detoxification and withdrawal in alcoholics. Trace amounts of GHB are produced endogenously (0.5-1.0 mg/L) in various tissues, including the brain, where it functions as both a precursor and a metabolite of the major inhibitory neurotransmitter γ-aminobutyric acid (GABA). Available information indicates that GHB serves as a neurotransmitter or neuromodulator in the GABAergic system, especially via binding to the GABA-B receptor subtype. Although GHB is listed as a controlled substance in many countries abuse still continues, owing to the availability of precursor drugs, γ-butyrolactone (GBL) and 1,4-butanediol (BD), which are not regulated. After ingestion both GBL and BD are rapidly converted into GHB (t½ ~1 min). The Cmax occurs after 20-40 min and GHB is then eliminated from plasma with a half-life of 30-50 min. Only about 1-5% of the dose of GHB is recoverable in urine and the window of detection is relatively short (3-10 h). This calls for expeditious sampling when evidence of drug use and/or abuse is required in forensic casework. The recreational dose of GHB is not easy to estimate and a concentration in plasma of ~100 mg/L produces euphoria and disinhibition, whereas 500 mg/L might cause death from cardiorespiratory depression. Effective antidotes to reverse the sedative and intoxicating effects of GHB do not exist. The poisoned patients require supportive care, vital signs should be monitored and the airways kept clear in case of emesis. After prolonged regular use of GHB tolerance and dependence develop and abrupt cessation of drug use leads to unpleasant withdrawal symptoms. There is no evidence-based protocol available to deal with GHB withdrawal, apart from administering benzodiazepines.

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.

Effects of ethanol on the toxicokinetics of methamphetamine in rabbits

In the current study, the effects of ethanol (EtOH) on toxicokinetics of methamphetamine (MA) and its metabolite amphetamine (AP) were investigated. A single dose of MA hydrochloride at 15 mg/Kg was given intragastrically, either alone (MA group; n = 8) or in conjunction with 3 g/Kg EtOH (MA+EtOH group; n = 8) to rabbits. In placebo group, normal saline only was given (placebo group; n = 4). Plasma and urine samples were collected and analyzed by gas chromatography/mass spectrometry (GC/MS) for MA and AP. Toxicokinetic parameters of MA and AP were determined using WinNonlin. Our results showed that toxicokinetic profiles of MA and AP in the two experimental groups were both fitted to an open two-compartment model with first-order kinetics. These were not affected by co-administration of EtOH. However, concomitant intake of EtOH significantly increased MA plasma absorption constant (Ka) and maximum concentration (Cmax). The Ka of MA was increased from 0.679/h ± 0.023/h to 0.964/h ± 0.033/h (P < 0.05, the mean Cmax from 1.408 mg/L ± 0.072 mg/L to 1.676 mg/L ± 0.135 mg/L (P < 0.05), whereas the Tmax was significantly decreased from 1.620 h ± 0.062 h to 1.259h ± 0.033h (P < 0.05). In contrast, no significant difference was observed on MA elimination. Furthermore, the plasma AP area under the curve (AUC0-30 h) increased from 5.281 mg/h/L ± 0.264 mg/h/L to.13.052 mg/h/L ± 0.956 mg/h/L and Cmax increased from 0.315 mg/L ± 0.010 mg/L to 0.423 mg/L ± 0.042 mg/L (P < 0.01). Taken together, co-administration of EtOH with MA significantly accelerated MA absorption and subsequent metabolism to AP, but did not have significant effect on MA elimination.

Toxicokinetics/Toxicodynamics of γ-hydroxybutyrate-ethanol intoxication: evaluation of potential treatment strategies

γ-Hydroxybutyrate (GHB), a common drug of abuse, is often coingested with ethanol. Increasing renal clearance via monocarboxylate transporter (MCT) inhibition represents a potential therapeutic strategy in GHB overdose, as does inhibition of GABAB receptors. In this study, we investigate toxicokinetic/toxicodynamic interactions between GHB-ethanol and efficacy of treatment options for GHB-ethanol intoxication in rats. Sedation was assessed using the endpoint of return-to-righting reflex. Respiration was assessed using plethysmography. Coadministration of 2.0 g/kg ethanol i.v. with 600 mg/kg GHB i.v. increased sleep time compared with GHB alone. Administration of ethanol to steady-state concentrations of 0.1-0.2% and 0.3-0.4% (w/v) did not affect toxicokinetics of 600 mg/kg GHB i.v., or respiratory rate, but did result in significantly lower peak tidal volumes compared with GHB alone. Oral administration of 2.5 g/kg ethanol had no significant effect on toxicokinetics of 1500 mg/kg orally administered GHB. Pretreatment with specific receptor inhibitors indicated no effect of GABAA receptor inhibition on sleep time or respiratory depression in GHB-ethanol intoxication. GABAB receptor inhibition partially prevented sedation and completely prevented respiratory depression. Ethanol increased fatality when administered at 0.1-0.2% (4 of 10) and 0.3-0.4% (9 of 10) versus 1500 mg/kg GHB i.v. alone (0 of 10). Treatment with the MCT inhibitor, l-lactate, significantly decreased sleep time after GHB-ethanol and decreased fatality at 0.1-0.2% (0 of 10) and 0.3-0.4% ethanol (5 of 10). Treatment with a GABAB receptor antagonist completely prevented fatality at 0.3-0.4% (0 of 10). These data indicate that ethanol potentiates the sedative and respiratory depressant effects of GHB, increasing the risk of fatality. MCT and GABAB receptor inhibition represent potentially effective treatments in GHB-ethanol intoxication.

Comparative abuse liability of GHB and ethanol in humans

Gamma-hydroxybutyric acid (GHB; sodium oxybate) is approved for narcolepsy symptom treatment, and it is also abused. This study compared the participant-rated, observer-rated effects, motor/cognitive, physiological, and reinforcing effects of GHB and ethanol in participants with histories of sedative (including alcohol) abuse. Fourteen participants lived on a residential unit for ∼1 month. Sessions were conducted Monday through Friday. Measures were taken before and repeatedly up to 24 hours after drug administration. Participants were administered GHB (1, 2, 4, 6, 8, and 10 g/70 kg), ethanol (12, 24, 48, 72, 96, and 120 g/70 kg), or placebo in a double-blind, within-subjects design. For safety, GHB and ethanol were administered in an ascending dose sequence, with placebos and both drugs intermixed across sessions. The sequence for each drug was stopped if significant impairment or intolerable effects occurred. Only 9 and 10 participants received the full dose range for GHB and ethanol, respectively. The highest doses of GHB and ethanol showed onset within 30 minutes, with peak effects at 60 minutes. GHB effects dissipated between 4 and 6 hours, whereas ethanol effects dissipated between 6 and 8 hours. Dose-related effects were observed for both drugs on a variety of measures assessing sedative drug effects, abuse liability, performance impairment, and physiological effects. Within-session measures of abuse liability were similar between the two drugs. However, postsession measures of abuse liability, including a direct preference test between the highest tolerated doses of each drug, suggested somewhat greater abuse liability for GHB, most likely as a result of the delayed aversive ethanol effects (e.g., headache).

Preliminary web-based measures development for GHB: expectancies, functions, and withdrawal

BACKGROUND

Much of what is understood regarding gamma hydroxybutyrate (GHB) treatment is based on hospital case studies for overdose and withdrawal, and there are currently no measures developed specifically for GHB or its analogs (e.g., gamma butyrolactone and 1,4-butanediol) to assess drug effect expectancies, reasons for starting use, withdrawal effects, and knowledge and opinions about use.

OBJECTIVES

This pilot study (N = 61) was conducted to begin measures development to assess experiences, functions of use, and opinions regarding use as indicated by respondents taking a Web-based survey.

METHODS

Minimum average partial correlation and parallel analysis procedures are employed to create scales.

RESULTS

Scales were developed to assess expectancies, reasons for use, withdrawal, and knowledge/opinions of use with median α = .79 and that account for 8.69-24.17% of the variance.

CONCLUSION

Scales have relatively good psychometric properties and replication is needed.

SCIENTIFIC SIGNIFICANCE

GHB-specific measures may greatly assist in furthering our understanding of protective and risk factors for use, and withdrawal phenomena.

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.

Case series of 226 γ-hydroxybutyrate-associated deaths: lethal toxicity and trauma

γ-Hydroxybutyrate (GHB) and its prodrugs are drugs of abuse that were also sold as "dietary supplements." Users present to emergency departments with overdose, impaired driving, withdrawal, and associated trauma. We compiled a series of GHB-associated deaths to elucidate lethal risks, GHB concentrations, cointoxicants, products, uses, and medical interventions. Death records were reviewed for toxicology, autopsy findings, and history. Inclusion cutoffs were as follows: 5/10 mg/L of GHB (antemortem blood/urine) and 50/20/7 mg/L of GHB (postmortem blood/urine/vitreous). Of 226 deaths included, 213 had cardiorespiratory arrest and 13 had fatal accidents. Seventy-eight deaths (35%) had no cointoxicants. Sixteen deaths involved "supplements" and 1 involved pharmaceutical GHB (Xyrem, Jazz Pharmaceuticals, Palo Alto, CA). Postmortem blood GHB was 18 to 4400 mg/L (median, 347 mg/L) in deaths negative for cointoxicants. Cardiorespiratory arrest occurred prehospital in 100% of 184 cases with available history. Of 72 cases with antemortem adverse effects reported, medical assistance was delayed or absent in 66; of these, acute GHB ingestion was known in 51, including 40 left to "sleep off" adverse effects. Thirty others were left "sleeping" and found dead. γ-Hydroxybutyrate is lethal even without cointoxicants, directly and through fatal accidents. Medical interventions were frequently delayed or absent despite known GHB ingestion, and witnessed adverse events and cardiorespiratory arrest occurred prehospital. Education is needed about the lethality of GHB and the necessity for prompt medical intervention.

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.

Illicit gamma-hydroxybutyrate (GHB) and pharmaceutical sodium oxybate (Xyrem): differences in characteristics and misuse

There are distinct differences in the accessibility, purity, dosing, and misuse associated with illicit gamma-hydroxybutyrate (GHB) compared to pharmaceutical sodium oxybate. Gamma-hydroxybutyrate sodium and sodium oxybate are the chemical and drug names, respectively, for the pharmaceutical product Xyrem (sodium oxybate) oral solution. However, the acronym GHB is also used to refer to illicit formulations that are used for non-medical purposes. This review highlights important differences between illicit GHB and sodium oxybate with regard to their relative abuse liability, which includes the likelihood and consequences of abuse. Data are summarized from the scientific literature; from national surveillance systems in the U.S., Europe, and Australia (for illicit GHB); and from clinical trials and post-marketing surveillance with sodium oxybate (Xyrem). In the U.S., the prevalence of illicit GHB use, abuse, intoxication, and overdose has declined from 2000, the year that GHB was scheduled, to the present and is lower than that of most other licit and illicit drugs. Abuse and misuse of the pharmaceutical product, sodium oxybate, has been rare over the 5 years since its introduction to the market, which is likely due in part to the risk management program associated with this product. Differences in the accessibility, purity, dosing, and misuse of illicit GHB and sodium oxybate suggest that risks associated with illicit GHB are greater than those associated with the pharmaceutical product sodium oxybate.

Cognitive, psychomotor, and subjective effects of sodium oxybate and triazolam in healthy volunteers

RATIONALE

Illicit gamma-hydroxybutyrate (GHB) has received attention as a "date rape drug" that produces robust amnesia; however, there is little experimental evidence in support of GHB's amnestic effects.

OBJECTIVES

This study compared the cognitive effects of GHB (sodium oxybate) with those of triazolam in healthy volunteers.

MATERIALS AND METHODS

Doses of sodium oxybate (1.125, 2.25, and 4.5 g/70 kg), triazolam (0.125, 0.25, and 0.5 mg/70 kg), and placebo were administered to 15 volunteers under repeated measures, counterbalanced, double-blind, double-dummy conditions. The time course and peak physiological, psychomotor, subjective, and cognitive effects were examined.

RESULTS

Sodium oxybate and triazolam produced similar increases in participant ratings of drug effects. Performance on psychomotor, working memory, and episodic memory tasks was impaired to a greater extent after triazolam than sodium oxybate.

CONCLUSIONS

Together, these data suggest that sodium oxybate produces less psychomotor and cognitive impairment than triazolam at doses that produce equivalent participant-rated subjective effects in healthy volunteers.

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.