The clinical toxicology of γ-hydroxybutyrate, γ-butyrolactone and 1,4-butanediol

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.

Prospective Investigation of the Performance of 2 Gamma-Hydroxybutyric Acid Tests: DrugCheck GHB Single Test and Viva-E GHB Immunoassay

BACKGROUND

Gamma-hydroxybutyric acid (GHB) is a recreational drug with central nervous system depressing effects that is often abused. A urine GHB point-of-care test can be of great diagnostic value. The objective of this prospective study was to determine the performance of the new DrugCheck GHB Single Test and the Viva-E GHB immunoassay for urine samples in emergency department patients.

METHODS

Patients presented to the emergency department of the OLVG hospital in Amsterdam with a Glasgow Coma Scale score <15 and potential drug of abuse intoxication were included in the study. Between June 2016 and October 2017, 375 patients were included. Using the DrugCheck GHB Single Test (Express Diagnostics Int'l, Blue Earth, MN) and the Viva-E GHB immunoassay (Siemens Healthineers, The Hague, the Netherlands), patients' urine samples were tested for GHB (cutoff for a positive result, 10 or 50 mcg/mL GHB). To ensure quality, the results obtained were compared with those generated using a validated gas chromatography method. The tests were considered reliable if specificity and sensitivity were both >90%. Possible cross-reactivity with ethanol was investigated by analyzing ethanol concentrations in patients' samples.

RESULTS

Seventy percentage of the included patients was men, and the median age was 34 years old. The DrugCheck GHB Single Test's specificity and sensitivity were 90.0% and 72.9%, respectively, and using 50 mcg/mL as a cutoff value, its specificity and sensitivity improved to 96.7% and 75.0%, respectively. Serum and urine ethanol levels in the false-positive group were significantly higher compared with those in the true-negative group. The specificity and sensitivity of the Viva-E GHB immunoassay (cutoff value of 50 mcg/mL and excluding samples with ethanol levels ≥2.0 g/L) were 99.4% and 93.5%, respectively.

CONCLUSIONS

The DrugCheck GHB Single Test's specificity was sufficient, whereas its sensitivity was poor, making it unsuitable for use at point-of-care. Contrarily, using 50 mcg/mL as the cutoff value and excluding samples with ethanol levels ≥2.0 g/L, the Viva-E GHB immunoassay showed acceptable results to detect clinically relevant GHB intoxications.

1,4-Butanediol overdose mimicking toxic alcohol exposure

Context: 1,4-butanediol (1,4-BD) is a gamma-hydroxybutyrate (GHB) analogue with a similarly narrow therapeutic window that is becoming a more common cause of recreational overdose. Reports of confirmed exposures are limited.Case details: A 44 year-old man who had consumed alcohol subsequently became unconscious after ingesting what was thought to be GHB. The presentation was not entirely consistent with GHB poisoning, including a longer duration of unconsciousness and features that mimicked toxic alcohol exposure including a high anion gap metabolic acidosis (HAGMA) and osmol gap. The patient was treated supportively with intubation, haemodiafiltration and intravenous ethanol until the diagnosis was refined using specific laboratory testing. The concentration of 1,4-BD was the highest reported in the literature and the outcome favourable.Discussion: This case highlights pharmacokinetic issues peculiar to 1,4-BD, including the interaction with ethanol which delays the onset of psychoactive effects from 1,4-BD's metabolite GHB, and dose-dependent pharmacokinetics. In overdose, 1,4-BD can induce a HAGMA and other features of toxic alcohol poisoning. Managing an unconscious patient with these features can prompt certain treatments until the diagnosis is refined, which can require specific laboratory testing to identify the culprit. The actual risk of toxic alcohol and other causes is adjusted on a case-by-case basis from the history of exposure and local epidemiology of substance use and poisoning.

GHB receptors - a new trend in psychopharmacology?

Introduction: Gamma-hydroxybutyric acid (GHB) is commonly known as a recreation drug or the so-called “date rape drug”. It is also used in medicine to treat narcolepsy and alcohol addiction. GHB has an affinity for two types of receptors: GABAB and the relatively recently discovered GHB receptors. GHB receptors were first cloned in 2003 in mice and then in 2007 in humans. So far, evidence has been presented for their impact on dopaminergic transmission, which may imply that they play a role in the pathogenesis of diseases such as schizophrenia. At the same time, it has been demonstrated that benzamide antipsychotic drugs have an affinity for GHB receptors, which is why it is postulated that some of the effects of these drugs may result precisely from this affinity.

Aim: The study presents the current state of knowledge about GHB receptors and their potential role in the pathogenesis of schizophrenia, and discusses drugs which show an affinity for this receptor.

Material and method: The literature review was based on a search of articles indexed between 1965 and 2018 in Medline, Google Scholar, ScienceDirect and Research Gate databases. The following search terms were used: GHB receptor, GHB, sulpiride, and amisulpride.

Result and discussion: 1. It is possible that GHB receptors are involved in the pathogenesis of schizophrenia, although more research is needed in this area. 2. Part of the effects of some benzamide antipsychotic drugs (such as amisulpride) may be due to their affinity for GHB receptors.

Newly Emerging Drugs of Abuse

Drug use and the associated overdose deaths have been a serious public health threat in the United States and the world. While traditional drugs of abuse such as cocaine remain popular, recreational use of newer synthetic drugs has continued to increase, but the prevalence of use is likely underestimated. In this review, epidemiology, chemistry, pharmacophysiology, clinical effects, laboratory detection, and clinical treatment are discussed for newly emerging drugs of abuse in the following classes: (1) opioids (e.g., fentanyl, fentanyl analogues, and mitragynine), (2) cannabinoids [THC and its analogues, alkylindole (e.g., JWH-018, JWH-073), cyclohexylphenol (e.g., CP-47,497), and indazole carboxamide (e.g., FUB-AMB, ADB-FUBINACA)], (3) stimulants and hallucinogens [β-keto amphetamines (e.g., methcathinone, methylone), pyrrolidinophenones (e.g., α-PVP, MDPV), and dimethoxyphenethylamine ("2C" and "NBOMe")], (4) dissociative agents (e.g., 3-MeO-PCP, methoxetamine, 2-oxo-PCE), and (5) sedative-hypnotics (e.g., gabapentin, baclofen, clonazolam, etizolam). It is critically important to coordinate hospital, medical examiner, and law enforcement personnel with laboratory services to respond to these emerging threats.

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.

Prevalence and Psychosocial Correlates of Party-Drug Use and Associated Problems among University Students in the Netherlands

BACKGROUND

Recent developments in drug use patterns call for an investigation of current party-drug use and associated problems among college students, who appear to be an important target population for harm reduction interventions.

OBJECTIVES

In addition to reporting on party-drug use prevalence, we investigated whether initial use and continuation of party-drug use among students was associated with demographic, personality and psychosocial factors.

METHODS

An online questionnaire was administered to 446 students from a Dutch university, inquiring about party-drug use, demographic characteristics, social norms and personality (big five, impulsiveness, aggression). Univariate and multivariate bootstrapped linear regression analyses were used.

RESULTS

Of all students, 22.9% indicated having used party-drugs at least once, with a notable sex difference (39.2% of men vs. 16.2% of women). In contrast to the reported trends in Dutch nightlife, GHB was used rarely (lifetime 1.6%) and new psychoactive substances (NPS; 6.7%) appeared almost equally popular as amphetamines (7.6%) and cocaine (7%). Mild health/psychosocial problems (e.g., doing embarrassing things, feeling unwell) were common (65%), whereas serious problems (e.g., being hospitalized) were rare. Neuroticism, extraversion, conscientiousness and impulsiveness were associated with lifetime but not regular party-drug use. Of all predictors, lifetime and regular party-drug use were most strongly related to lenient injunctive and descriptive norms in friends, and a low motivation to comply with parents.

CONCLUSIONS

Our findings indicate that harm reduction/preventive interventions might profit from focusing on social norms, and targeting students who are highly involved in a pro-party-drug environment while experiencing less parental influence.

Interpreting γ-hydroxybutyrate concentrations for clinical and forensic purposes

INTRODUCTION

γ-Hydroxybutyric acid is an endogenous substance, a therapeutic agent, and a recreational drug of abuse. This psychoactive substance acts as a depressant of the central nervous system and is commonly encountered in clinical and forensic practice, including impaired drivers, poisoned patients, and drug-related intoxication deaths.

OBJECTIVE

The aim of this review is to assist clinical and forensic practitioners with the interpretation of γ-hydroxybutyric acid concentrations in blood, urine, and alternative biological specimens from living and deceased persons.

METHODS

The information sources used to prepare this review were PubMed, Scopus, and Web-of-Science. These databases were searched using keywords γ-hydroxybutyrate (GHB), blood, urine, alternative specimens, non-conventional biological matrices, saliva, oral fluid, sweat, hair, vitreous humor (VH), brain, cerebrospinal fluid (CSF), dried blood spots (DBS), breast milk, and various combinations thereof. The resulting 4228 references were screened to exclude duplicates, which left 1980 articles for further consideration. These publications were carefully evaluated by taking into account the main aims of the review and 143 scientific papers were considered relevant. Analytical methods: The analytical methods used to determine γ-hydroxybutyric acid in blood and other biological specimens make use of gas- or liquid-chromatography coupled to mass spectrometry. These hyphenated techniques are accurate, precise, and specific for their intended purposes and the lower limit of quantitation in blood and other specimens is 0.5 mg/L or less. Human pharmacokinetics: GHB is rapidly absorbed from the gut and distributes into the total body water compartment. Only a small fraction of the dose (1-2%) is excreted unchanged in the urine. The plasma elimination half-life of γ-hydroxybutyric acid is short, being only about 0.5-0.9 h, which requires timely sampling of blood and other biological specimens for clinical and forensic analysis. Endogenous concentrations of GHB in blood: GHB is both an endogenous metabolite and a drug of abuse, which complicates interpretation of the laboratory results of analysis. Moreover, the concentrations of GHB in blood and other specimens tend to increase after sampling, especially in autopsy cases. This requires the use of practical "cut-off" concentrations to avoid reporting false positive results. These cut-offs are different for different biological specimen types. Concentrations of GHB in clinical and forensic practice: As a recreational drug GHB is predominantly used by young males (94%) with a mean age of 27.1 years. The mean (median) and range of concentrations in blood from apprehended drivers was 90 mg/L (82 mg/L) and 8-600 mg/L, respectively. The concentration distributions in blood taken from living and deceased persons overlapped, although the mean (median) and range of concentrations were higher in intoxication deaths; 640 mg/L (280 mg/L) and 30-9200 mg/L, respectively. Analysis of GHB in alternative specimens: All biological fluids and tissue containing water are suitable for the analysis of GHB. Examples of alternative specimens discussed in this review are CSF, saliva, hair strands, breast milk, DBS, VH, and brain tissue.

CONCLUSIONS

Body fluids for the analysis of GHB must be obtained as quickly as possible after a poisoned patient is admitted to hospital or after a person is arrested for a drug-related crime to enhance chances of detecting the drug. The sampling of urine lengthens the window of detection by 3-4 h compared with blood samples, but with longer delays between last intake of GHB and obtaining specimens, hair strands, and/or nails might be the only option. In postmortem toxicology, the concentrations of drugs tend to be more stable in bladder urine, VH, and CSF compared with blood, because these sampling sites are protected from the spread of bacteria from the gut. Accordingly, the relationship between blood and urine concentrations of GHB furnishes useful information when drug intoxication deaths are investigated.

Slimming to the Death: Herbalife®-Associated Fatal Acute Liver Failure-Heavy Metals, Toxic Compounds, Bacterial Contaminants and Psychotropic Agents in Products Sold in India

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The safety evaluation of food flavouring substances: the role of metabolic studies

The safety assessment of a flavour substance examines several factors, including metabolic and physiological disposition data. The present article provides an overview of the metabolism and disposition of flavour substances by identifying general applicable principles of metabolism to illustrate how information on metabolic fate is taken into account in their safety evaluation. The metabolism of the majority of flavour substances involves a series both of enzymatic and non-enzymatic biotransformation that often results in products that are more hydrophilic and more readily excretable than their precursors. Flavours can undergo metabolic reactions, such as oxidation, reduction, or hydrolysis that alter a functional group relative to the parent compound. The altered functional group may serve as a reaction site for a subsequent metabolic transformation. Metabolic intermediates undergo conjugation with an endogenous agent such as glucuronic acid, sulphate, glutathione, amino acids, or acetate. Such conjugates are typically readily excreted through the kidneys and liver. This paper summarizes the types of metabolic reactions that have been documented for flavour substances that are added to the human food chain, the methodologies available for metabolic studies, and the factors that affect the metabolic fate of a flavour substance.

Baclofen to Prevent Relapse in Gamma-Hydroxybutyrate (GHB)-Dependent Patients: A Multicentre, Open-Label, Non-Randomized, Controlled Trial

BACKGROUND

Gamma-hydroxybutyrate (GHB) dependence is associated with a severe, potentially lethal, withdrawal syndrome and relapse rates as high as 60% within 3 months of detoxification. Baclofen has been shown to decrease self-administration of GHB in mice and reduce relapse in a case series of GHB-dependent patients. Controlled studies on the effectiveness of baclofen to prevent relapse in GHB-dependent patients are lacking.

AIM

The aim of this study was to assess effectiveness of baclofen in preventing relapse in GHB-dependent patients.

METHODS

This was an out-patient, multicentre, open-label, non-randomized, controlled trial in GHB-dependent patients (n = 107) in the Netherlands. Treatment as usual (TAU, n = 70) was compared with TAU plus baclofen 45-60 mg/day for 3 months (n = 37). Outcome measures were rates of lapse (any use) and relapse (using GHB on average once a week or more), based on self-report. Side effects were monitored with a baclofen side-effects questionnaire. Treatment groups were compared using Chi square analyses, with both per-protocol (PP) and intention-to-treat (ITT) analyses.

RESULTS

GHB-dependent patients treated with baclofen after detoxification showed no reduced lapse rates, but reduced relapse and dropout rates, compared with patients receiving TAU only (24 vs 50%). While both ITT and PP analyses revealed similar results, the effectiveness of baclofen prescribed PP was slightly higher than in ITT analysis. Patients reported overall limited side effects, with the most frequently reported being feeling tired (28%), sleepiness (14%) and feeling depressed (14%). No serious adverse events were reported.

CONCLUSIONS

This study showed potential effectiveness of baclofen in preventing relapse in patients with GHB dependence after detoxification. Though promising, future studies with longer follow-up and a randomized double-blind design should confirm these findings before recommendations for clinical practice can be made.

CLINICAL TRIAL REGISTRATION

Netherlands Trial Register with number NTR4528.

Intoxication with GHB/GBL: characteristics and trends from ambulance-attended overdoses

BACKGROUND

Overdoses from so-called "club drugs" (GHB/GBL) have become a more frequent cause of overdoses attended by ambulance services. Given its availability, affordability, and lack of awareness of risks, there is a common misconception among users that the drug is relatively safe.

METHODS

This study reviewed ambulance records in Bergen, Norway between 2009 and 2015 for cases of acute poisonings, particularly from suspected GHB/GBL intoxication.

RESULTS

In total, 1112 cases of GHB and GBL poisoning were identified. GHB was suspected for 995 (89%) of the patients. Men made up the majority of the cases (n = 752, 67.6%) with a median age of 27 years old. Temporal trends for GHB/GBL overdoses displayed a late-night, weekend pattern. The most frequent initial symptoms reported were unconsciousness, or reduced consciousness. Most of the patients required further treatment and transport. During the period from 2009 to 2015, there was a nearly 50% decrease in GHB/GBL overdoses from 2013 to 2014.

DISCUSSION

The characteristics of GHB/GBL overdose victims shed light on this patient group. The decrease in incidence over the years may be partly due to a legal ban on GBL in Norway, declared in 2010. It may also be due to an increase in the use of MDMA/ecstasy.

CONCLUSION

The review of ambulance records on the prehospital treatment of overdoses can be beneficial in monitoring, preparing, and prevention efforts aimed to benefit this vulnerable group.

Effect of chronic γ-hydroxybutyrate (GHB) administration on GHB toxicokinetics and GHB-induced respiratory depression

BACKGROUND

γ-hydroxybutyrate (GHB) has a high potential for illicit use; overdose of this compound results in sedation, respiratory depression and death. Tolerance to the hypnotic/sedative and electroencephalogram effects of GHB occurs with chronic GHB administration; however, tolerance to respiratory depression has not been evaluated. GHB toxicodynamic effects are mediated predominantly by GABA_B receptors. Chronic treatment may affect monocarboxylate transporters (MCTs) and alter the absorption, renal clearance and brain uptake of GHB.

OBJECTIVES

To determine effects of chronic GHB dosing on GHB toxicokinetics, GHB-induced respiratory depression, and MCT expression.

METHODS

Rats were administered GHB 600 mg/kg intravenously daily for 5 days. Plasma, urine and tissue samples and respiratory measurements were obtained on days 1 and 5. Plasma and urine were analyzed for GHB by LC/MS/MS and tissue samples for expression of MCT1, 2 and 4 and their accessory proteins by QRT-PCR.

RESULTS

No differences in GHB pharmacokinetics or respiratory depression were observed between days 1 and 5. Opposing changes in MCT1 and MCT4 mRNA expression were observed in kidney samples on day 5 compared to GHB-naïve animals, and MCT4 expression was increased in the intestine.

CONCLUSIONS

The lack of tolerance observed with GHB-induced respiratory depression, in contrast to the tolerance reported for the sedative/hypnotic and electroencephalogram effects, suggests that different GABA_B receptor subtypes may be involved in different GABA_B-mediated toxicodynamic effects of GHB. Chronic or binge users of GHB may be at no less risk for fatality from respiratory arrest with a GHB overdose than with a single dose of GHB.

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.

Guidelines for biological treatment of substance use and related disorders, part 1: Alcoholism, first revision

These practice guidelines for the biological treatment of alcohol use disorders are an update of the first edition, published in 2008, which was developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP). For this 2016 revision, we performed a systematic review (MEDLINE/PUBMED database, Cochrane Library) of all available publications pertaining to the biological treatment of alcoholism and extracted data from national guidelines. The Task Force evaluated the identified literature with respect to the strength of evidence for the efficacy of each medication and subsequently categorised it into six levels of evidence (A-F) and five levels of recommendation (1-5). Thus, the current guidelines provide a clinically and scientifically relevant, evidence-based update of our earlier recommendations. These guidelines are intended for use by clinicians and practitioners who evaluate and treat people with alcohol use disorders and are primarily concerned with the biological treatment of adults with such disorders.

Detoxification with titration and tapering in gamma-hydroxybutyrate (GHB) dependent patients: The Dutch GHB monitor project

BACKGROUND AND AIMS

Gamma-hydroxybutyrate (GHB) detoxification procedures have been insufficiently studied for effectiveness and safety. Based on case reports, benzodiazepines are generally regarded as first-choice agents in GHB detoxification. Detoxification by titration and tapering (DeTiTap) with pharmaceutical GHB in an open-label consecutive case series of 23 GHB-dependent patients showed to be feasible, effective and safe. This study further explored the feasibility, effectiveness and safety of this detoxification procedure in a large group of patients.

METHOD

A large observational multicenter study was carried out in six addiction treatment centers in the Netherlands. GHB-dependent inpatients (229 unique patients, 274 admissions) were titrated on and tapered off with pharmaceutical GHB.

RESULTS

Successful detoxification was achieved in 85% of cases. Detoxification was carried out in 12.5days in most patients. The DeTiTap procedure proved to be feasible and significantly reduced the experienced withdrawal symptoms and craving (p≤0.001). Several symptoms were found to influence the course of subjective withdrawal symptoms. During detoxification, psychological symptoms such as depression, anxiety, and stress decreased (p≤0.05). The main complications were hypertension and anxiety. Six patients were sent to the general hospital for observation, but all six were able to continue detoxification in the addiction treatment centers. Most patients (69%) relapsed within three months after detoxification.

CONCLUSIONS

The DeTiTap procedure using pharmaceutical GHB seems a safe alternative to benzodiazepines as a GHB detoxification procedure. However, the high relapse rates warrant further investigation.

Novel Psychoactive Substances-Recent Progress on Neuropharmacological Mechanisms of Action for Selected Drugs

A feature of human culture is that we can learn to consume chemical compounds, derived from natural plants or synthetic fabrication, for their psychoactive effects. These drugs change the mental state and/or the behavioral performance of an individual and can be instrumentalized for various purposes. After the emergence of a novel psychoactive substance (NPS) and a period of experimental consumption, personal and medical benefits and harm potential of the NPS can be estimated on evidence base. This may lead to a legal classification of the NPS, which may range from limited medical use, controlled availability up to a complete ban of the drug form publically accepted use. With these measures, however, a drug does not disappear, but frequently continues to be used, which eventually allows an even better estimate of the drug's properties. Thus, only in rare cases, there is a final verdict that is no more questioned. Instead, the view on a drug can change from tolerable to harmful but may also involve the new establishment of a desired medical application to a previously harmful drug. Here, we provide a summary review on a number of NPS for which the neuropharmacological evaluation has made important progress in recent years. They include mitragynine ("Kratom"), synthetic cannabinoids (e.g., "Spice"), dimethyltryptamine and novel serotonergic hallucinogens, the cathinones mephedrone and methylone, ketamine and novel dissociative drugs, γ-hydroxybutyrate, γ-butyrolactone, and 1,4-butanediol. This review shows not only emerging harm potentials but also some potential medical applications.

Pharmacological Treatment in γ-Hydroxybutyrate (GHB) and γ-Butyrolactone (GBL) Dependence: Detoxification and Relapse Prevention

The misuse of γ-hydroxybutyrate (GHB) for recreational purposes has resulted in an increase in GHB-related problems such as intoxications, dependence and withdrawal in several countries in Europe, Australia and the US over the last decade. However, prevalence rates of misuse of GHB and its precursor, γ-butyrolactone (GBL), are still relatively low. In this qualitative review paper, after a short introduction on the pharmacology of GHB/GBL, followed by a summary of the epidemiology of GHB abuse, an overview of GHB dependence syndrome and GHB/GBL withdrawal syndrome is provided. Finally, the existing literature on management of GHB detoxification, both planned and unplanned, as well as the available management of GHB withdrawal syndrome, is summarized. Although no systematic studies on detoxification and management of withdrawal have been performed to date, general recommendations are given on pharmacological treatment and preferred treatment setting.

The Neurobiological Mechanisms of Gamma-Hydroxybutyrate Dependence and Withdrawal and Their Clinical Relevance: A Review

OBJECTIVE

x03B3;-Hydroxybutyrate (GHB) has gained popularity as a drug of abuse. In the Netherlands the number of patients in treatment for GHB dependence has increased sharply. Clinical presentation of GHB withdrawal can be life threatening. We aim, through this overview, to explore the neurobiological pathways causing GHB dependency and withdrawal, and their implications for treatment choices.

METHODS

In this work we review the literature discussing the findings from animal models to clinical studies focused on the neurobiological pathways of endogenous but mainly exogenous GHB.

RESULTS

Chronic abuse of GHB exerts multifarious neurotransmitter and neuromodulator effects on x03B3;-aminobutyric acid (GABA), glutamate, dopamine, serotonin, norepinephrine and cholinergic systems. Moreover, important effects on neurosteroidogenesis and oxytocin release are wielded. GHB acts mainly via a bidirectional effect on GABAB receptors (GABABR; subunits GABAB1 and GABAB2), depending on the subunit of the GIRK (G-protein-dependent ion inwardly rectifying potassium) channel involved, and an indirect effect of the cortical and limbic inputs outside the nucleus accumbens. GHB also activates a specific GHB receptor and β1-subunits of α4-GABAAR. Reversing this complex interaction of neurobiological mechanisms by the abrupt cessation of GHB use results in a withdrawal syndrome with a diversity of symptoms of different intensity, depending on the pattern of GHB abuse.

CONCLUSION

The GHB withdrawal symptoms cannot be related to a single mechanism or neurological pathway, which implies that different medication combinations are needed for treatment. A single drug class, such as benzodiazepines, gabapentin or antipsychotics, is unlikely to be sufficient to avoid life-threatening complications. Detoxification by means of titration and tapering of pharmaceutical GHB can be considered as a promising treatment that could make polypharmacy redundant.

An observed rise in γ-hydroxybutyrate-associated deaths in London: Evidence to suggest a possible link with concomitant rise in chemsex

BACKGROUND

Gamma-hydroxybutyrate (GHB) is the drug most linked to acute harm out of those used in chemsex, the incidence of which is reported to be increasing. However, there have been few systematic studies of the harms associated with GHB use. We investigated GHB-associated deaths from London coroners' jurisdictions between 2011 and 2015.

METHODS

Blood and urine samples were collected by pathologists and submitted for toxicological analysis at the request of coroners. Data from the Toxicology Unit, Imperial College London was retrospectively analysed. This comprised of 6633 cases from seven out of eight coroners' jurisdictions in London that underwent toxicological analysis between January 2011 and December 2015.

RESULTS

A total of 61 GHB-associated deaths (0.92% of total cases), 184 cocaine-associated deaths (2.8% of total cases) and 83 MDMA-associated deaths (1.3% of total cases) were identified. There was a 119% increase in the proportion of GHB-associated deaths detected in 2015 compared to 2014. Over the same time period there was a 25% increase in cocaine-associated deaths and a 10% decrease in MDMA-associated deaths.

CONCLUSIONS

Our data suggest that GHB-associated deaths are increasing in London, and that this is likely at least in part due to increasing use of GHB for chemsex. Further studies on the use of GHB are urgently required to understand the extent of its use, whether this is as prevalent in other major urban areas in the UK, and the full extent of the harms it causes.

Presentations to an urban emergency department in Switzerland due to acute γ-hydroxybutyrate toxicity

Background

γ-Hydroxybutyrate (GHB) is a drug of abuse with dose-dependent sedative effects. Systematic data on the acute toxicity of GHB from emergency department (ED) presentations over a long period of time are currently missing from the literature. The present study described the clinical features of GHB toxicity.

Methods

Retrospective case series of GHB intoxications seen in an urban ED.

Results

From January 2002 to September 2015, 78 GHB-related intoxication cases were recorded (71 % male patients). The mean ± SD age was 29 ± 8 years. The co-use of alcohol and/or other illicit drugs was reported in 65 % of the cases. Neurological symptoms other than central nervous system depression included agitation (40 %) and clonus (21 %). The most frequent reasons for admission were coma (64 %) and agitation (23 %). The median time to regain consciousness was 90 min (range, 3–400 min). Sudden recovery was reported in 25 cases (32 %). Coma was not significantly associated with polyintoxication. Coma occurred in 77 % of the alcohol co-users and in 62 % ofthe non-alcohol users (p=0.052). The mean recovery time in comatose patients was 142 min in patients with co-use of alcohol compared with 89 min in patients without alcohol co-use (p=0.07). Alcohol co-use was not significantly associated with nausea/vomiting (p=0.07). The co-use of stimulants was not significantly associated with non-responsive coma (Glasgow Coma Scale = 3) or mean recovery time. Analytical confirmation of GHB was available in 37 cases (47 %), with additional quantitative analysis in 20 cases. The median GHB concentration was 240 mg/L (range, 8.3–373 mg/L). Intoxication was severe in 72 % of the cases. No fatalities occurred, and 72 % of the patients were discharged directly home from the ED.

Discussion

There were trend associations between alcohol co-use and frequency and length of coma and nausea/vomiting which did not reach the significance level (all p=0.05-0.07) but may nevertheless be clinically relevant. As the exact time of use is not always known, and co-use of other substances can affect the severity of poisoning, no definitive conclusions can be drawn regarding the association between GHB concentration and severity.

Conclusion

Impaired consciousness and agitation were typical findings of GHB intoxication. The co-use of alcohol and/or other illicit substances is common but was not significantly associated with the severity of the intoxications in our study.

Pharmacologic, Pharmacokinetic, and Clinical Assessment of Illicitly Used γ-Hydroxybutyrate

γ-Hydroxybutyrate (GHB) is a common drug of abuse and poses important health risks to users in the form of respiratory, cardiovascular, mental, or traumatic adverse events. GHB has non-dose-proportional effects and pharmacologic effects such as sedation and retrograde amnesia, which can incapacitate people targeted for assault. It has Krebs cycle metabolism, rapid clearance, relative hydrophilicity, and unique drug interactions. Promptly seeking medical attention during intentional or inadvertent overdose is critical to survival, as is prompt supportive care once medical personnel are alerted. People drugged before assault also need to promptly notify authorities because the period to detect the drug in the urine or blood is brief and the ultimate metabolites are carbon dioxide and water. After acute treatment has passed, withdrawal could be severe in chronic abusers that could harm the patient directly or drive them back into reuse.

Outpatient treatment of acute poisoning by substances of abuse: a prospective observational cohort study

Background

Procedures for the clinical assessment of acute poisoning by substances of abuse should identify patients in need of hospital admission and avoid hazardous discharges, while keeping the observation time short. We assess the safety of a systematic procedure developed at the Oslo Accident and Emergency Outpatient Clinic (OAEOC).

Methods

All patients 12 years and older treated for acute poisoning by substances of abuse at the OAEOC were included consecutively from October 2011 to September 2012. Data were collected on pre-set registration forms. Information on re-presentations to health services nation-wide during the first week following discharge was retrieved from the Norwegian Patient Register and from local electronic medical records. Information on fatalities was obtained from the Norwegian Cause of Death Registry.

Results

There were 2343 cases of acute poisoning by substances of abuse. The main toxic agent was ethanol in 1291 (55 %) cases, opioids in 539 (23 %), benzodiazepines in 194 (8 %), central stimulants in 132 (6 %), and gamma-hydroxybutyrate (GHB) in 105 (4 %). Median observation time was four hours. The patient was hospitalised in 391 (17 %) cases. Two patients died during the first week following discharge, both from a new opioid poisoning. Among 1952 discharges, 375 (19 %) patients re-presented at the OAEOC or a hospital within a week; 13 (0.7 %) with a diagnosis missed at the index episode, 169 (9 %) with a new poisoning, 31 (2 %) for follow-up of concomitant conditions diagnosed at index, and 162 (8 %) for unrelated events. Among the patients with missed diagnoses, five needed further treatment for the same poisoning episode, two were admitted with psychosis, one had hemorrhagic gastritis, another had fractures in need of surgery and four had minor injuries.

Conclusion

The procedure in use at the OAEOC can be considered safe and could be implemented elsewhere. The high re-presentation rate calls for better follow-up.

How to assess gay, bisexual and other men who have sex with men for chemsex

OBJECTIVES

Sexualised substance use, 'chemsex', is being increasingly reported by gay, bisexual and other men who have sex with men (GBMSM) in sexual health clinics. We aim to describe the evidence base and practical ways in which clinicians can assess and advise patients disclosing chemsex.

METHODS

We review published literature on chemsex, discuss vulnerability to substance use, highlight the importance of clinical communication and discuss a management approach.

RESULTS

GBMSM are vulnerable to substance use problems, which interplay with mental, physical and sexual health. Knowledge on sexualised drug use and related communication skills are essential to facilitating disclosure. Identifying sexual health and other consequences of harmful drug use may motivate patients to seek change.

CONCLUSIONS

Sexual health clinicians are well placed to make more holistic assessments of GBMSM accessing their services to promote broader sexual health and well-being beyond the management of HIV and sexually transmitted infections (STIs) alone.

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.

Biocompatibility of common polyimides with human endothelial cells for a cardiovascular microsensor

The cardiovasculature is an emerging niche for polyimide microdevices, yet the biocompatibility of polyimides with human endothelial cells has not been reported in the literature. In this study, we have evaluated an experimental polyimide-based pressure sensor for biological safety to determine its suitability for intravascular operation by using an in vitro model of human endothelium, following ISO 10993-5 protocols for extract tests and direct contact tests. First, SV-HCEC cells were incubated with extracts derived from common microfabrication polyimides utilized in the transducer (PMDA-ODA, BPDA-PPD, and a proprietary thermoplastic adhesive), and then labeled with selective probes to evaluate the effect of the polyimides on mitochondria and cell viability. Flow cytometry analysis showed that incubation of SV-HCECs with polyimide extracts resulted in no significant change in mitochondrial membrane potential (detected by JC-1) or apoptotic (annexin V) and necrotic (propidium iodide) cell death, when compared to incubation with extracts of high-density polyethylene (HDPE) and untreated cells used as negative controls. Second, primary human endothelial cells were incubated in direct contact with the completed sensor and then labeled with selective probes for live-dead analysis (calcein-AM, ethidium homodimer-1). Endothelial cells showed no loss of viability when compared to negative controls. Combined, the studies show no significant change in early markers of stress or more strict markers of viability in endothelial cells treated with the polyimides tested. We conclude that these common microfabrication polyimides and the derived sensor are not cytotoxic to human endothelial cells, the primary cell type that cardiovascular sensors will contact in vivo.

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.

Increasing use of 'party drugs' in people living with HIV on antiretrovirals: a concern for patient safety

Use of 'party drugs', a particular set of recreational drugs used in the context of 'ChemSex', is frequent among MSM living with HIV. A recently published observational study showed that more than half of HIV-infected MSM interviewed reported use of illicit substances in the previous 3 months, with frequent concomitant use of three or more drugs. These substances are a combination of 'club drugs' (methylenedioxymethamphetamine, gamma-hydroxybutyrate, ketamine, benzodiazepine) and drugs that are more specifically used in a sexualized context (methamphetamine, mephedrone, poppers and erectile dysfunction agents). Although formal data on pharmacokinetic or pharmacodynamic interactions between recreational drugs and antiretroviral agents are lacking, information regarding potentially toxic interactions can be theorized or sometimes conclusions may be drawn from case studies and cohort observational studies. However, the risk of coadministering party drugs and antiretrovirals should not be overestimated. The major risk for a drug-drug interaction is when using ritonavir-boosting or cobicistat-boosting agents, and maybe some nonnucleoside reverse transcriptase inhibitors. Knowledge of the metabolic pathways of 'party drugs' may help in advising patients on which illicit substances have a high potential for drug-drug interactions, as this is not the case for all.

GHB for cataplexy: Possible mode of action

The sleep disorder narcolepsy is caused by the loss of orexinergic neurones in the lateral hypothalamus. A troublesome symptom of narcolepsy is cataplexy, the sudden loss of muscle tone in response to strong emotions. It can be alleviated by antidepressants and sodium oxybate (γ-hydroxybutyric acid (GHB)). It is likely that the noradrenergic nucleus locus coeruleus (LC) is involved since it is essential for the maintenance of muscle tone, and ceases to fire during cataplectic attacks. Furthermore, alpha-2 adrenoceptors proliferate in the LC in cataplexy, probably due to 'heterologous denervation supersensitivity' resulting from the loss/weakening of the orexinergic input to the LC. This would lead to the sensitization of the autoinhibition mechanism of LC neurones mediated by inhibitory alpha-2 adrenoceptors ('autoreceptors'). Thus the excitatory input from the amygdala to the LC, activated by an emotional stimulus, would lead to the 'switching off' of LC activity via the supersensitive auto-inhibition mechanism. GHB is an agonist at both γ-aminobutyric acid (GABA) GABA (B) and GHB receptors that may be a subtype of an extrasynaptic GABA(A) receptor. GHB may prevent a cataplectic attack by dampening the tone of LC neurones via the stimulation of inhibitory extrasynaptic GABA receptors in the LC, and thus increasing the threshold for autoinhibition.

Baclofen as relapse prevention in the treatment of gamma-hydroxybutyrate dependence: a case series

In the last decade, gamma-hydroxybutyrate (GHB) abuse and dependence have increased. It has been reported that GHB dependence has a high rate of relapse, serious complications of intoxication, and a potentially life-threatening withdrawal syndrome. Nevertheless, in clinical practice, there is no known medical treatment to support GHB relapse prevention. We describe a case series of patients who were supported through an off-label treatment with baclofen to avoid a relapse into GHB abuse, for a period of 12 weeks. Nine of 11 patients did not relapse while taking a dose ranging from 30 to 60 mg per day, one patient relapsed after 5 weeks, and one stopped after 7 weeks. Baclofen was well tolerated; patients reported mild side effects such as fatigue, nausea, dry mouth, excessive sweating, and depressive feelings. Although systematic evidence is still lacking, our practice-based experience suggests that treatment with baclofen to assist abstinence might be effective in patients with GHB dependence. Further systematic controlled studies are necessary to establish the exact efficacy and safety of baclofen as relapse prevention for GHB-dependent patients.

Baclofen as relapse prevention in the treatment of Gamma- Hydroxybutyrate (GHB) dependence: an open label study

BACKGROUND

GHB dependence is a growing health problem in several western countries, especially the Netherlands. Attempts to stop using GHB are often followed by relapse shortly after successful detoxification. Craving for GHB use and co-morbid psychiatric symptom levels are thought to be the major factors contributing to the high relapse rates. Given its pharmacological profile, baclofen might prove an effective anti-craving agent for patients with GHB dependence. The aim of the current study is to assess the potential of baclofen as an anti-craving agent relapse prevention intervention in GHB dependent patients.

METHODS/DESIGN

In an open label non-randomized trial treatment with baclofen to a maximum of 60 mg/day will be compared with treatment as usual (TAU) in recently detoxified GHB dependent patients (n = 80). The primary outcome measure will be the level of GHB use. Secondary outcome measures are craving levels, psychiatric symptom levels and quality of life. Questionnaires will be administered during 12 weeks of baclofen treatment and at follow-up (six months after the start of treatment).

DISCUSSION

It is hypothesized that baclofen treatment compared to TAU will be associated with significantly reduced GHB use. In addition, we hypothesize that baclofen treatment will be associated with decreased craving and anxiety levels, and higher quality of life. If results are in line with our hypotheses, further studies on the efficacy of baclofen using placebo controlled designs and long term follow-up are warranted.

TRIAL REGISTRATION

The Netherlands Trial Register with number NTR4528 . Registered 19 April 2014.

Novel psychoactive substances of interest for psychiatry

Novel psychoactive substances include synthetic cannabinoids, cathinone derivatives, psychedelic phenethylamines, novel stimulants, synthetic opioids, tryptamine derivatives, phencyclidine-like dissociatives, piperazines, GABA-A/B receptor agonists, a range of prescribed medications, psychoactive plants/herbs, and a large series of performance and image enhancing drugs. Users are typically attracted by these substances due to their intense psychoactive effects and likely lack of detection in routine drug screenings. This paper aims at providing psychiatrists with updated knowledge of the clinical pharmacology and psychopathological consequences of the use of these substances. Indeed, these drugs act on a range of neurotransmitter pathways/receptors whose imbalance has been associated with psychopathological conditions, including dopamine, cannabinoid CB1, GABA-A/B, 5-HT2A, glutamate, and k opioid receptors. An overall approach in terms of clinical management is briefly discussed.

Evolving P450pyr monooxygenase for highly regioselective terminal hydroxylation of n-butanol to 1,4-butanediol

Directed evolution of a P450pyr created I83M/I82T mutant as the first catalyst for highly regioselective terminal hydroxylation of n-butanol to 1,4-butanediol.

The outcome of agitation in poisoned patients in an Iranian tertiary care university hospital

Introduction. This study was conducted to evaluate and document the frequency and causes of agitation, the symptoms accompanying this condition in intoxications, relationship between agitation score on admission and different variables, and the outcome of therapy in a tertiary care referral poisoning center in Iran. Methods. In this prospective observational study which was done in 2012, 3010 patients were screened for agitation at the time of admission using the Richmond Agitation Sedation Scale. Demographic data including age, gender, and the drug ingested were also recorded. The patients' outcome was categorized as recovery without complications, recovery with complications (hyperthermia, renal failure, and other causes), and death. Results. Agitation was observed in 56 patients (males, n = 41), mostly aged 19–40 years (n = 38) and more frequently in illegal substance (stimulants, opioids and also alcohol) abusers. Agitation score was not significantly related to the age, gender, and previous history of psychiatric disorders. Forty nine patients had recovery without any complication. The need for mechanical ventilation was the most frequent complication. None of the patients died. Conclusion. Drug abuse seems to be a must-to-consider etiology for patients presenting with acute agitation and its morbidity and mortality could be low in agitated poisoning cases if prompt supportive care is performed.