Gamma-hydroxybutyric acid

Severe gamma-hydroxybutyrate withdrawal with delirium, hemodynamic lability, and rhabdomyolysis: A case series

BACKGROUND AND OBJECTIVES

Gamma-hydroxybutyrate (GHB) use is clinically important in both the settings of overdose and withdrawal. GHB withdrawal varies in severity, and although mild cases can be managed outpatient, there are a range of presentations that include progression to severe withdrawal that require inpatient hospitalization.

METHODS

We report a case series of two patients with severe GHB withdrawal who experienced complications of delirium, hemodynamic lability, and rhabdomyolysis and describe the treatment of these two cases of complex withdrawal.

RESULTS

The first patient was successfully treated with a combination of a benzodiazepine taper and symptom-triggered benzodiazepines with baclofen as an adjunct. The second patient had more severe symptoms and required intubation with a midazolam infusion, dexmedetomidine infusion, phenobarbital, baclofen, and a combination of a benzodiazepine taper and symptom-triggered benzodiazepines.

DISCUSSION AND CONCLUSIONS

This case series highlights the potential complications of GHB withdrawal including delirium, hemodynamic lability, and rhabdomyolysis. Although rare in the United States, those working in addiction should have familiarity with the clinical course and complications of severe GHB withdrawal.

SCIENTIFIC SIGNIFICANCE

As one of the few detailed reports on severe GHB withdrawal and its potential complications, our findings extend the current body of literature by detailing the successful application of a multi-modal treatment of severe GHB withdrawal.

The Glutamate/GABA-Glutamine Cycle: Insights, Updates, and Advances

Synaptic homeostasis of the principal neurotransmitters glutamate and GABA is tightly regulated by an intricate metabolic coupling between neurons and astrocytes known as the glutamate/GABA-glutamine cycle. In this cycle, astrocytes take up glutamate and GABA from the synapse and convert these neurotransmitters into glutamine. Astrocytic glutamine is subsequently transferred to neurons, serving as the principal precursor for neuronal glutamate and GABA synthesis. The glutamate/GABA-glutamine cycle integrates multiple cellular processes, including neurotransmitter release, uptake, synthesis, and metabolism. All of these processes are deeply interdependent and closely coupled to cellular energy metabolism. Astrocytes display highly active mitochondrial oxidative metabolism and several unique metabolic features, including glycogen storage and pyruvate carboxylation, which are essential to sustain continuous glutamine release. However, new roles of oligodendrocytes and microglia in neurotransmitter recycling are emerging. Malfunction of the glutamate/GABA-glutamine cycle can lead to severe synaptic disruptions and may be implicated in several brain diseases. Here, I review central aspects and recent advances of the glutamate/GABA-glutamine cycle to highlight how the cycle is functionally connected to critical brain functions and metabolism. First, an overview of glutamate, GABA, and glutamine transport is provided in relation to neurotransmitter recycling. Then, central metabolic aspects of the glutamate/GABA-glutamine cycle are reviewed, with a special emphasis on the critical metabolic roles of glial cells. Finally, I discuss how aberrant neurotransmitter recycling is linked to neurodegeneration and disease, focusing on astrocyte metabolic dysfunction and brain lipid homeostasis as emerging pathological mechanisms. Instead of viewing the glutamate/GABA-glutamine cycle as individual biochemical processes, a more holistic and integrative approach is needed to advance our understanding of how neurotransmitter recycling modulates brain function in both health and disease.

Efficacy and Safety of Sodium Oxybate in Isolated Focal Laryngeal Dystonia: A Phase IIb Double-Blind Placebo-Controlled Cross-Over Randomized Clinical Trial

OBJECTIVE

To examine the efficacy and safety of sodium oxybate versus placebo in a phase IIb randomized double-blind placebo-controlled 2-period cross-over clinical trial in patients with isolated laryngeal dystonia (LD).

METHODS

The study was conducted from January 2018 to December 2021, pausing during the COVID-19 pandemic, at Massachusetts Eye and Ear in 106 patients with alcohol-responsive (EtOH+) and alcohol-non-responsive (EtOH-) LD (53 to receive 1.5g of sodium oxybate first, 53 to receive matching placebo first). The primary outcome was a change from baseline in LD symptom severity 40 minutes after drug intake. Safety was based on vital signs, cognitive function, suicidality, daytime sleepiness, and adverse events. Patients, investigators, and outcome assessors were masked to study procedures.

RESULTS

Compared to baseline, EtOH+ but not EtOH- patients had a statistically significant improvement in LD symptoms following sodium oxybate versus placebo (EtOH+: 98.75% confidence interval [CI] = 0.6-26.9; p = 0.008; EtOH-: 98.75% CI = -6.2 to 18.7; p = 0.42). Statistically significant minimum drug efficacy in EtOH+ patients was found at ≥16% symptom improvement (OR = 2.09; 98.75% CI = 0.75-5.80; p = 0.036), with an average of 40.81% benefits (98.75% CI = 34.7-48.6). Drug efficacy waned by 300 minutes after intake without a rebound. No changes were found in cognitive function, suicidality, or vital signs. Common adverse events included mild dizziness, nausea, and daytime sleepiness.

INTERPRETATION

Sodium oxybate showed clinically meaningful improvement of symptoms in EtOH+ LD patients, with acceptable tolerability. Sodium oxybate offers the first pathophysiologically relevant oral treatment for laryngeal dystonia. ANN NEUROL 2025;97:329-343.

GHB, Chemsex and Chemical Submission: Investigating the Role of Sexuality on Victim Empathy and Blame Attribution in Drug-Facilitated Sexual Assault against Men

Literature is sparse regarding men's attitudes towards male sexual assault and the role that the sexuality of those involved may have. Despite the high prevalence of chemsex and GHB (gamma-hydroxybutyrate) participation among men who have sex with men, no study has yet investigated attitudes towards such. Utilising a community sample of 141 UK men, participants were randomly assigned into one of six conditions based on victim sexuality (heterosexual or homosexual) and the drug used present during the sexual assault (chemsex, chemical submission, or no drugs). All participants completed the Male Rape Victim and Perpetrator Blaming Scale and Victim-Blaming Empathy Scale to measure victim-blame and empathy attributions. Results of a two-way MANOVA revealed a significant difference between participant gender and empathic ratings, with heterosexual participants significantly less likely to empathise than their homosexual counterparts. A non-significant difference was observed between the conditions alongside a non-significant interaction. Nevertheless, results indicate that victims in the chemsex condition, along with heterosexual victims, encountered the greatest victim-blaming attributions and the lowest rates of participant empathy overall. Findings overall appear to indicate a general decline in victim-blame attitudes towards men who have sex with men, though a level of uncertainty was apparent among the sample. Implications and limitations of the work are discussed alongside the importance of future research and psychoeducation interventions.

Glymphatic dysfunction coincides with lower GABA levels and sleep disturbances in succinic semialdehyde dehydrogenase deficiency

Succinic semialdehyde dehydrogenase deficiency (SSADHD) is an inherited metabolic disorder of γ-aminobutyrate (GABA) catabolism. Cerebral waste clearance along glymphatic perivascular spaces depends on aquaporin 4 (AQP4) water channels, the function of which was shown to be influenced by GABA. Sleep disturbances are associated independently with SSADHD and glymphatic dysfunction. This study aimed to determine whether indices of the hyperGABAergic state characteristic of SSADHD coincide with glymphatic dysfunction and sleep disturbances and to explicate the modulatory effect that GABA may have on the glymphatic system. The study included 42 individuals (21 with SSADHD; 21 healthy controls) who underwent brain MRIs and magnetic resonance spectroscopy (MRS) for assessment of glymphatic dysfunction and cortical GABA, plasma GABA measurements, and circadian clock gene expression. The SSADHD subjects responded to an additional Children's Sleep Habits Questionnaire (CSHQ). Compared with the control group, SSADHD subjects did not differ in sex and age but had a higher severity of enlarged perivascular spaces in the centrum semiovale (p < 0.001), basal ganglia (p = 0.01), and midbrain (p = 0.001), as well as a higher MRS-derived GABA/NAA peak (p < 0.001). Within the SSADHD group, the severity of glymphatic dysfunction was specific for a lower MRS-derived GABA/NAA (p = 0.04) and lower plasma GABA (p = 0.004). Additionally, the degree of their glymphatic dysfunction correlated with the CSHQ-estimated sleep disturbances scores (R = 5.18, p = 0.03). In the control group, EPVS burden did not correlate with age or cerebral and plasma GABA values. The modulatory effect that GABA may exert on the glymphatic system has therapeutic implications for sleep-related disorders and neurodegenerative conditions associated with glymphatic dysfunction.

Treatment of Gamma Hydroxybutyrate Withdrawal in a Pregnant Female: A Case Report

BACKGROUND

Gamma hydroxybutyrate (GHB) is used illicitly for its sedative hypnotic effects, and those who take it regularly are at risk of developing a substance use disorder. Withdrawal from GHB can include severe symptoms that may require medical management. For GHB use and withdrawal during pregnancy, there are no evidence- or practice-based guidelines to follow, and there is only minimal research literature.

CASE SUMMARY

We present the case of a 32-year-old woman, G1P0 at 29 weeks and 6 days of gestation, admitted to the perinatal unit at a tertiary hospital for GHB withdrawal management and stabilization. GHB withdrawal was managed with a combination of baclofen and diazepam. We report the dosing and tapering of these medications throughout her 14-day admission. Withdrawal symptoms were well managed with this medication protocol, and she did not experience any features of complicated withdrawal. The patient later presented to hospital in preterm labor and precipitously delivered a healthy, preterm infant male at 34 weeks and 5 days of gestation. At 7 months postpartum, the patient continued to engage with perinatal addiction service, reported no use of GHB since her admission, and was parenting her healthy son.

CLINICAL SIGNIFICANCE

There is a paucity of guidelines for managing GHB withdrawal in pregnancy. This case demonstrates good clinical outcomes administering a short-term combination of diazepam and baclofen during the third trimester of pregnancy. This case helps to fill a gap in the literature and may inform future research or clinical decision-making in similar situations.

Current treatments of alcohol use disorder

Emerging treatments for alcohol dependence reveal an intricate interplay of neurobiological, psychological, and circumstantial factors that contribute to Alcohol Use Disorder (AUD). The approved strategies balancing these factors involve extensive manipulations of neurotransmitter systems such as GABA, Glutamate, Dopamine, Serotonin, and Acetylcholine. Innovative developments are engaging mechanisms such as GABA reuptake inhibition and allosteric modulation. Closer scrutiny is placed on the role of Glutamate in chronic alcohol consumption, with treatments like NMDA receptor antagonists and antiglutamatergic medications showing significant promise. Complementing these neurobiological approaches is the progressive shift towards Personalized Medicine. This strategy emphasizes unique genetic, epigenetic and physiological factors, employing pharmacogenomic principles to optimize treatment response. Concurrently, psychological therapies have become an integral part of the treatment landscape, tackling the cognitive-behavioral dimension of addiction. In instances of AUD comorbidity with other psychiatric disorders, Personalized Medicine becomes pivotal, ensuring treatment and prognosis are closely defined by individual characteristics, as exemplified by Lesch Typology models. Given the high global prevalence and wide distribution of AUD, a persistent necessity exists for development and improvement of treatments. Current research efforts are steadily paving paths towards more sophisticated, effective typology-based treatments: a testament to the recognized imperative for enhanced treatment strategies. The potential encapsulated within the ongoing research suggests a promising future where the clinical relevance of current strategies is not just maintained but significantly improved to effectively counter alcohol dependence.

Modular access to chiral bridged piperidine-γ-butyrolactones via catalytic asymmetric allylation/aza-Prins cyclization/lactonization sequences

Chiral functionalized piperidine and lactone heterocycles are widely spread in natural products and drug candidates with promising pharmacological properties. However, there remains no general asymmetric methodologies that enable rapid assemble both critical biologically important units into one three-dimensional chiral molecule. Herein, we describe a straightforward relay strategy for the construction of enantioenriched bridged piperidine-γ-butyrolactone skeletons incorporating three skipped stereocenters via asymmetric allylic alkylation and aza-Prins cyclization/lactonization sequences. The excellent enantioselectivity control in asymmetric allylation with the simplest allylic precursor is enabled by the synergistic Cu/Ir-catalyzed protocol; the success of aza-Prins cyclization/lactonization can be attributed to the pivotal role of the ester substituent, which acts as a preferential intramolecular nucleophile to terminate the aza-Prins intermediacy of piperid-4-yl cation species. The resulting chiral piperidine-γ-butyrolactone bridged-heterocyclic products show impressive preliminary biological activities against a panel of cancer cell lines.

Stereodivergent synthesis of α-fluoro α-azaaryl γ-butyrolactones via cooperative copper and iridium catalysis

The development of stereodivergent synthetic methods to access all four stereoisomers of biologically important α-fluoro γ-butyrolactones containing vicinal stereocenters is of great importance and poses a formidable challenge owing to ring strain and steric hindrance. Herein, a novel asymmetric [3+2] annulation of α-fluoro α-azaaryl acetates with vinylethylene carbonate was successfully developed through Cu/Ir-catalyzed cascade allylic alkylation/lactonization, affording a variety of enantioenriched α-fluoro γ-butyrolactones bearing vicinal stereogenic centers with high reaction efficiency and excellent levels of both stereoselectivity and regioselectivity (up to 98% yield, generally >20:1 dr and >99% ee). Notably, all four stereoisomers of these pharmaceutically valuable molecules could be accessed individually via simple permutations of two enantiomeric catalysts. In addition, other azaaryl acetates bearing α-methyl, α-chlorine or α-phenyl group were tolerated well in this transformation. Reaction mechanistic investigations were conducted to explore the process of this bimetallic catalysis based on the results of reaction intermediates, isotopic labelling experiments, and kinetic studies.

Reduced evoked cortical beta and gamma activity and neuronal synchronization in succinic semialdehyde dehydrogenase deficiency, a disorder of γ-aminobutyric acid metabolism

Succinic semialdehyde dehydrogenase deficiency is a rare autosomal recessively inherited metabolic disorder of γ-aminobutyric acid catabolism manifested by intellectual disability, expressive aphasia, movement disorders, psychiatric ailments and epilepsy. Subjects with succinic semialdehyde dehydrogenase deficiency are characterized by elevated γ-aminobutyric acid and related metabolites, such as γ-guanidinobutyric acid, and an age-dependent downregulation of cerebral γ-aminobutyric acid receptors. These findings indicate impaired γ-aminobutyric acid and γ-aminobutyric acid sub-type A (GABAA) receptor signalling as major factors underlying the pathophysiology of this neurometabolic disorder. We studied the cortical oscillation patterns and their relationship with γ-aminobutyric acid metabolism in 18 children affected by this condition and 10 healthy controls. Using high-density EEG, we recorded somatosensory cortical responses and resting-state activity. Using electrical source imaging, we estimated the relative power changes (compared with baseline) in both stimulus-evoked and stimulus-induced responses for physiologically relevant frequency bands and resting-state power. Stimulus-evoked oscillations are phase locked to the stimulus, whereas induced oscillations are not. Power changes for both evoked and induced responses as well as resting-state power were correlated with plasma γ-aminobutyric acid and γ-guanidinobutyric acid concentrations and with cortical γ-aminobutyric acid measured by proton magnetic resonance spectroscopy. Plasma γ-aminobutyric acid, γ-guanidinobutyric acid and cortical γ-aminobutyric acid were higher in patients than in controls (P < 0.001 for both). Beta and gamma relative power were suppressed for evoked responses in patients versus controls (P < 0.01). No group differences were observed for induced activity (P > 0.05). The mean gamma frequency of evoked responses was lower in patients versus controls (P = 0.002). Resting-state activity was suppressed in patients for theta (P = 0.011) and gamma (P < 0.001) bands. Evoked power changes were inversely correlated with plasma γ-aminobutyric acid and with γ-guanidinobutyric acid for beta (P < 0.001) and gamma (P < 0.001) bands. Similar relationships were observed between the evoked power changes and cortical γ-aminobutyric acid for all tested areas in the beta band (P < 0.001) and for the posterior cingulate gyrus in the gamma band (P < 0.001). We also observed a negative correlation between resting-state activity and plasma γ-aminobutyric acid and γ-guanidinobutyric acid for theta (P < 0.001; P = 0.003), alpha (P = 0.003; P = 0.02) and gamma (P = 0.02; P = 0.01) bands. Our findings indicate that increased γ-aminobutyric acid concentration is associated with reduced sensory-evoked beta and gamma activity and impaired neuronal synchronization in patients with succinic semialdehyde dehydrogenase deficiency. This further elucidates the pathophysiology of this neurometabolic disorder and serves as a potential biomarker for therapeutic trials.

Sodium Oxybate in Alcohol-Responsive Essential Tremor of Voice: An Open-Label Phase II Study

BACKGROUND

Essential tremor of voice (ETv) is characterized by involuntary oscillations of laryngeal and upper airway muscles, causing rhythmic alterations in pitch and loudness during both passive breathing and active laryngeal tasks, such as speaking and singing. Treatment of ETv is challenging and typically less effective compared with treatment of ET affecting extremities.

OBJECTIVE

We conducted a proof-of-concept, open-label phase II study to examine the efficacy and central effects of sodium oxybate in patients with alcohol-responsive ETv.

METHODS

All subjects received 1.0 to 1.5 g of oral sodium oxybate and underwent brain functional magnetic resonance imaging. The primary endpoint was the number of patients (% from total) with reduced ETv symptoms by at least 10% at about 40 to 45 minutes after sodium oxybate intake based on the combined visual analog scale score of ETv symptom severity. The secondary endpoint included changes in brain activity after sodium oxybate intake compared to baseline.

RESULTS

Sodium oxybate reduced ETv symptoms on average by 40.8% in 92.9% of patients. Drug effects were observed about 40 to 45 minutes after intake, lasting about 3.5 hours, and gradually wearing off by the end of the fifth hour. The central effects of sodium oxybate were associated with normalized activity in the cerebellum, inferior/superior parietal lobules, inferior frontal gyrus, and insula and re-established functional relationships between these regions.

CONCLUSIONS

Sodium oxybate showed high efficacy in ETv patients, with a likely central action on disorder pathophysiology. Sodium oxybate may be an effective novel oral drug for treatment of alcohol-responsive ETv patients. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

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.

Facile access to chiral γ-butyrolactones via rhodium-catalysed asymmetric hydrogenation of γ-butenolides and γ-hydroxybutenolides

The highly efficient Rh/ZhaoPhos-catalysed asymmetric hydrogenation of γ-butenolides and γ-hydroxybutenolides was successfully developed. This protocol provides an efficient and practical approach to the synthesis of various chiral γ-butyrolactones, which are synthetically valuable building blocks of diverse natural products and therapeutic substances, with excellent results (up to >99% conversion and 99% ee). Further follow-up transformations have been revealed to accomplish creative and efficient synthetic routes for several enantiomerically enriched drugs via this catalytic methodology.

Nocturnal sodium oxybate increases the anterior cingulate cortex magnetic resonance glutamate signal upon awakening

Clinical guidelines recommend sodium oxybate (SXB; the sodium salt of γ-hydroxybutyrate) for the treatment of disturbed sleep and excessive daytime sleepiness in narcolepsy, yet the underlying mode of action is elusive. In a randomised controlled trial in 20 healthy volunteers, we aimed at establishing neurochemical changes in the anterior cingulate cortex (ACC) following SXB-enhanced sleep. The ACC is a core neural hub regulating vigilance in humans. At 2:30 a.m., we administered in a double-blind cross-over manner an oral dose of 50 mg/kg SXB or placebo, to enhance electroencephalography-defined sleep intensity in the second half of nocturnal sleep (11:00 p.m. to 7:00 a.m.). Upon scheduled awakening, we assessed subjective sleepiness, tiredness and mood and measured two-dimensional, J-resolved, point-resolved magnetic resonance spectroscopy (PRESS) localisation at 3-Tesla field strength. Following brain scanning, we used validated tools to quantify psychomotor vigilance test (PVT) performance and executive functioning. We analysed the data with independent t tests, false discovery rate (FDR) corrected for multiple comparisons. The morning glutamate signal (at 8:30 a.m.) in the ACC was specifically increased after SXB-enhanced sleep in all participants in whom good-quality spectroscopy data were available (n = 16; p_FDR  < 0.002). Further, global vigilance (10th-90th inter-percentile range on the PVT) was improved (p_FDR  < 0.04) and median PVT response time was shorter (p_FDR  < 0.04) compared to placebo. The data indicate that elevated glutamate in the ACC could provide a neurochemical mechanism underlying SXB's pro-vigilant efficacy in disorders of hypersomnolence.

Astrocytes regulate inhibitory neurotransmission through GABA uptake, metabolism, and recycling

Synaptic regulation of the primary inhibitory neurotransmitter γ-aminobutyric acid (GABA) is essential for brain function. Cerebral GABA homeostasis is tightly regulated through multiple mechanisms and is directly coupled to the metabolic collaboration between neurons and astrocytes. In this essay, we outline and discuss the fundamental roles of astrocytes in regulating synaptic GABA signaling. A major fraction of synaptic GABA is removed from the synapse by astrocytic uptake. Astrocytes utilize GABA as a metabolic substrate to support glutamine synthesis. The astrocyte-derived glutamine is subsequently transferred to neurons where it serves as the primary precursor of neuronal GABA synthesis. The flow of GABA and glutamine between neurons and astrocytes is collectively termed the GABA-glutamine cycle and is essential to sustain GABA synthesis and inhibitory signaling. In certain brain areas, astrocytes are even capable of synthesizing and releasing GABA to modulate inhibitory transmission. The majority of oxidative GABA metabolism in the brain takes place in astrocytes, which also leads to synthesis of the GABA-related metabolite γ-hydroxybutyric acid (GHB). The physiological roles of endogenous GHB remain unclear, but may be related to regulation of tonic inhibition and synaptic plasticity. Disrupted inhibitory signaling and dysfunctional astrocyte GABA handling are implicated in several diseases including epilepsy and Alzheimer's disease. Synaptic GABA homeostasis is under astrocytic control and astrocyte GABA uptake, metabolism, and recycling may therefore serve as relevant targets to ameliorate pathological inhibitory signaling.

Withdrawal of Gamma-Hydroxybutyrate in a Saudi Male Patient: A Case Report

Gamma-hydroxybutyrate (GHB) is a central nervous system (CNS) depressant with limited clinical use but has been misused in the last few decades. During intoxication, the patient may develop CNS depression and may have agitation, while during withdrawal, the patient can present with severe agitation or delirium. Here, we report the case of a 30-year-old Saudi male patient who was brought by his brother to the emergency department (ED) with agitation and delirium. The patient's friend stated the patient had been misusing GHB mixed with alcohol for the last seven months, with the last use occurring 24 hours before the ED presentation. The patient was put on a five-point restraint for safety concerns and received supportive therapy. After two days of admission, the patient completely recovered. As the patient provided a limited history of his GHB misuse, the clinician lacked sufficient information to determine whether the patient was intoxicated or withdrawing. Clinicians in Saudi Arabia need to be highly suspicious of GHB misuse when treating patients with drug intoxication or withdrawal.

Metabolomics insights into the prenatal exposure effects of polybrominated diphenyl ethers on neonatal birth outcomes

BACKGROUND

Effects of polybrominated diphenyl ethers (PBDEs) on neonatal birth outcomes vary across previous studies, and the related mechanism investigation remains poorly understood, especially at the metabolic level.

OBJECTIVES

To evaluate the associations between prenatal PBDEs exposure and neonatal birth outcomes including gestational age, neonatal weight, birth length, head circumference (HC), Apgar score at 1 min (Apgar1) and 5 min, and further reveal the underlying metabolic disorders in a population-based birth cohort study.

METHODS

Gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) based targeted method and GC-MS based untargeted method were respectively conducted to obtain PBDE levels and metabolic profiles of 200 placental tissue samples from a typical e-waste recycling area (Guiyu) and reference area (Haojiang) in China. Spearman correlation and regression analyses were applied to assess the associations between the placental PBDE levels and birth outcomes. Metabolome-wide association studies and the meet-in-the-middle approach were employed to explore disruptions linking PBDE exposures and the corresponding adverse birth outcomes.

RESULTS

Eight out of 27 PBDE congeners were detected in placenta with more than 50% frequency in at least one district and significantly higher in Guiyu than those in Haojiang. The lower HC and Apgar1 had significant associations with PBDE exposures after adjustment for potential confounders. A total of 66, 16 and 14 metabolites were significantly correlated with PBDE exposures, HC and Apgar1, respectively. 4 and 12 PBDE-related metabolites were significantly associated with the risks of decreasing neonatal HC and Apgar1. The disrupted metabolites were mainly involved in the pentose phosphate pathway, ascorbate metabolism, threonine metabolism, butanoate metabolism, lipid metabolism, and arginine biosynthesis.

CONCLUSIONS

In this birth cohort, higher placental PBDE levels were significantly associated with the lower HC and Apgar1. The associations might be modified by multiple metabolic disturbances through increasing oxidative stress, mediating neurotoxicity, maternal gut microbiota dysbiosis and vasodilatation regulation.

Toxicological Characterization of GHB as a Performance-Enhancing Drug

Performance-enhancing drugs (PEDs) are represented by several compounds used to ameliorate the image, the appearance, or an athletic or non-athletic performance. Gamma-hydroxybutyrate (GHB) is an endogenous molecule first used as anesthetic and then marketed as a nutritional supplement with a wide diffusion in the bodybuilding community. The aim of the present work is to provide a toxicological characterization of the use of GHB as a PED, including the scientific basis for its use, the patterns of use/abuse, and the health risks arising from its consumption in this peculiar recreative setting. A literature search was performed on multiple databases including experimental studies on humans and animals as well as epidemiological reports and forensic case reports/series. Experimental studies demonstrated that the use of GHB as a PED is motivated by the release of growth hormone and the induction of sleep. However, the panel of desired performance-related effects was much wider in real cases and epidemiological studies. Even though the use of GHB among bodybuilders has decreased, its use to enhance some kind of performance, particularly sexual ones or social-communicative ones, as well as means to increase mood and perceived energy, is still common.

Stereodivergent Synthesis of Enantioenriched γ-Butyrolactones Bearing Two Vicinal Stereocenters Enabled by Synergistic Copper and Iridium Catalysis

By virtue of a fundamentally new reaction model of azomethine ylide serving as a two-atom synthon, we present the first example of stereodivergent preparation of γ-butyrolactones via synergistic Cu/Ir-catalyzed asymmetric cascade allylation/lactonization, and all four stereoisomers of γ-butyrolactones bearing two vicinal stereocenters are accessible with excellent diastereoselective and enantioselective control. The chiral Ir^III -π-allyl intermediate was separated and characterized to understand the origin of the regio- and stereoselectivity of the initial C-C bond formation process. Control experiments shed some light on the catalyst/substrate and catalyst/catalyst interactions in this dual catalytic system to rationalize the related kinetic/dynamic kinetic resolution process with different catalyst combinations. The enantioenriched γ-butyrolactone products were converted into an array of structurally complex chiral molecules and organocatalysts that were otherwise inaccessible.

ADHD symptoms in neurometabolic diseases: Underlying mechanisms and clinical implications

Neurometabolic diseases (NMDs) are typically caused by genetic abnormalities affecting enzyme functions, which in turn interfere with normal development and activity of the nervous system. Although the individual disorders are rare, NMDs are collectively relatively common and often lead to lifelong difficulties and high societal costs. Neuropsychiatric manifestations, including ADHD symptoms, are prominent in many NMDs, also when the primary biochemical defect originates in cells and tissues outside the nervous system. ADHD symptoms have been described in phenylketonuria, tyrosinemias, alkaptonuria, succinic semialdehyde dehydrogenase deficiency, X-linked ichthyosis, maple syrup urine disease, and several mitochondrial disorders, but are probably present in many other NMDs and may pose diagnostic and therapeutic challenges. Here we review current literature linking NMDs with ADHD symptoms. We cite emerging evidence that many NMDs converge on common neurochemical mechanisms that interfere with monoamine neurotransmitter synthesis, transport, metabolism, or receptor functions, mechanisms that are also considered central in ADHD pathophysiology and treatment. Finally, we discuss the therapeutic implications of these findings and propose a path forward to increase our understanding of these relationships.

Successful Treatment of Severe Gamma-Hydroxybutyric Acid Withdrawal Syndrome With Dantrolene

The prevalence of gamma-butyrolactone/gamma-hydroxybutyric acid (GBL/GHB) use is increasing. The gravity and number of incidents with this drug are relatively high. A feared complication is addiction and its withdrawal syndrome, which can be life-threatening and is difficult to treat. We present the case of a 31-year-old man, admitted to the ICU because of accidental GBL withdrawal. The patient was tachycardic, sweaty, extremely agitated, and showed signs of psychosis. High doses of benzodiazepines, propofol, sufentanil, and quetiapine could not sedate the patient sufficiently. Dosing with pharmaceutical GHB was challenging due to severe gastric retention. As the patient developed hyperthermia and rhabdomyolysis, signs of a neuroleptic malignant syndrome (NMS), he was treated with dantrolene. After 14 days, the patient was discharged to a psychiatric clinic for further treatment. GHB affects multiple neurotransmitters and chronic use causes the up- or down-regulation of several receptors. During GHB withdrawal, the patient developed a hyperexcitable state, in which there was insufficient gamma-aminobutyric acid (GABA) (the most important inhibiting neurotransmitter) and an abundance of glutamate (the most important excitatory neurotransmitter). High-dose benzodiazepines are often advocated as the first-line treatment, but benzodiazepine resistance has frequently been reported. Therefore, treatment with pharmaceutical GHB is advised. Patients with GHB-withdrawal who have clinical signs of NMS can be treated with dantrolene because it regulates the distorted calcium secretion and affects the serotonin and cholinergic system.

Unity in diversity: A systematic review on the GHB using population

BACKGROUND

Over the past decades gamma-hydroxybutyrate (GHB) has emerged as a popular drug with high potential of (ab)use due to its euphoric and relaxing effects. An overview of different populations using GHB is urgently needed, since this would enable development of adequate prevention and treatment policies to diminish the risks associated with GHB use. We systematically reviewed literature on different GHB using populations, comparing demographic characteristics, GHB use patterns, psychosocial aspects and psychiatric comorbidity.

METHODS

We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using Rayyan software. Original studies published from January 1997 up to October 2019 on GHB use were included. Out of 80 full-text articles, 60 articles of 51 unique studies were included. Most studies included people using GHB 1) presenting at emergency departments (n = 22), 2) recruited from the general population (n = 11), or 3) presenting at addiction care (n = 8).

RESULTS

Three main sub-populations of people using GHB are described in the literature: people using GHB recreationally without adverse effects; people using GHB recreationally with adverse effects, and people with dependence on GHB. These groups show considerable overlap in gender, age range, and comorbid substance use, as well as amount of GHB use per occasion. Differences are related to frequency and function of GHB use, the number of comas experienced, as well as work status, and psychiatric comorbidity.

CONCLUSION

Policy interventions should aim at preventing the transition from recreational substance use to GHB use, as most users are experienced recreational substance users prior to starting GHB use. When people use GHB regularly, interventions should aim at reducing the level of GHB use and preventing GHB use-related harm. Longitudinal studies and population-based probability sampling are required for more insight in the dynamics of GHB use in different sub-populations, and the transition from one group to the other, ultimately leading to dependence on GHB.

Metabolic Alterations Associated with γ-Hydroxybutyric Acid and the Potential of Metabolites as Biomarkers of Its Exposure

γ-Hydroxybutyric acid (GHB) is an endogenous short chain fatty acid that acts as a neurotransmitter and neuromodulator in the mammalian brain. It has often been illegally abused or misused due to its strong anesthetic effect, particularly in drug-facilitated crimes worldwide. However, proving its ingestion is not straightforward because of the difficulty in distinguishing between endogenous and exogenous GHB, as well as its rapid metabolism. Metabolomics and metabolism studies have recently been used to identify potential biomarkers of GHB exposure. This mini-review provides an overview of GHB-associated metabolic alterations and explores the potential of metabolites for application as biomarkers of GHB exposure. For this, we discuss the biosynthesis and metabolism of GHB, analytical issues of GHB in biological samples, alterations in metabolic pathways, and changes in the levels of GHB conjugates in biological samples from animal and human studies. Metabolic alterations in organic acids, amino acids, and polyamines in urine enable discrimination between GHB-ingested animals or humans and controls. The potential of GHB conjugates has been investigated in a variety of clinical settings. Despite the recent growth in the application of metabolomics and metabolism studies associated with GHB exposure, it remains challenging to distinguish between endogenous and exogenous GHB. This review highlights the significance of further metabolomics and metabolism studies for the discovery of practical peripheral biomarkers of GHB exposure.

Functional analysis of thirty-four suspected pathogenic missense variants in ALDH5A1 gene associated with succinic semialdehyde dehydrogenase deficiency

Deficiency of succinate semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5a1 (ALDH5A1), OMIM 271980, 610045), the second enzyme of GABA degradation, represents a rare autosomal-recessively inherited disorder which manifests metabolically as gamma-hydroxybutyric aciduria. The neurological phenotype includes intellectual disability, autism spectrum, epilepsy and sleep and behavior disturbances. Approximately 70 variants have been reported in the ALDH5A1 gene, half of them being missense variants. In this study, 34 missense variants, of which 22 novel, were evaluated by in silico analyses using PolyPhen2 and SIFT prediction tools. Subsequently, the effect of these variants on SSADH activity was studied by transient overexpression in HEK293 cells. These studies showed severe enzymatic activity impairment for 27 out of 34 alleles, normal activity for one allele and a broad range of residual activities (25 to 74%) for six alleles. To better evaluate the alleles that showed residual activity above 25%, we generated an SSADH-deficient HEK293-Flp-In cell line using CRISPR-Cas9, in which these alleles were stably expressed. This model proved essential in the classification as deficient for one out of the seven studied alleles. For 8 out of 34 addressed alleles, there were discrepant results among the used prediction tools, and/or in correlating the results of the prediction tools with the functional data. In case of diagnostic urgency of missense alleles, we propose the use of the transient transfection model for confirmation of their effect on the SSADH catalytic function, since this model resulted in fast and robust functional characterization for the majority of the tested variants. In selected cases, stable transfections can be considered and may prove valuable.

Pharmacotherapeutic management of acute alcohol withdrawal syndrome in critically Ill patients

INTRODUCTION

Alcohol withdrawal syndrome is a common and life-threatening condition in patients suffering from alcohol use disorder. Treatment of this syndrome is challenging, especially in patients that are critically ill, either because of withdrawal symptoms or underlying conditions. For the treatment, several pharmacological agents exist, such as benzodiazepines, barbiturates, or dexmedetomidine. Nonetheless, as alcohol withdrawal syndromes can occur in every clinical setting, it is necessary to provide a guideline for clinicians confronted with this syndrome in varying clinical contexts.

AREAS COVERED

The authors provide a systematic review of the literature found in PubMed and Embase following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

EXPERT OPINION

For the treatment of alcohol withdrawal syndrome, medications targeting the GABA system are preferred. Benzodiazepines are regarded as the gold standard. However, as many adjunct therapeutic options exist, it is essential to find symptom-triggered approaches and treatment protocols for the variety of clinical contexts. Apart from that, it is necessary to compare protocols toward clinical variables rather than investigating medications that are in use for the treatment of alcohol withdrawal syndrome.

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.

Sleep-promoting effects of threonine link amino acid metabolism in Drosophila neuron to GABAergic control of sleep drive

Emerging evidence indicates the role of amino acid metabolism in sleep regulation. Here we demonstrate sleep-promoting effects of dietary threonine (SPET) in Drosophila. Dietary threonine markedly increased daily sleep amount and decreased the latency to sleep onset in a dose-dependent manner. High levels of synaptic GABA or pharmacological activation of metabotropic GABA receptors (GABA_B-R) suppressed SPET. By contrast, synaptic blockade of GABAergic neurons or transgenic depletion of GABA_B-R in the ellipsoid body R2 neurons enhanced sleep drive non-additively with SPET. Dietary threonine reduced GABA levels, weakened metabotropic GABA responses in R2 neurons, and ameliorated memory deficits in plasticity mutants. Moreover, genetic elevation of neuronal threonine levels was sufficient for facilitating sleep onset. Taken together, these data define threonine as a physiologically relevant, sleep-promoting molecule that may intimately link neuronal metabolism of amino acids to GABAergic control of sleep drive via the neuronal substrate of sleep homeostasis.

Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).

Clinical relevance of ethanol coingestion in patients with GHB/GBL intoxication

OBJECTIVE

Ethanol intake can increase the sedative effects of gamma-hydroxybutyrate/gamma-butyrolactone (GHB/GBL), although the real clinical impact is unknown. We studied the clinical impact of the co-ingestion of ethanol in patients presenting to the Emergency Department (ED) with acute toxicity related to GHB/GBL use.

METHOD

We performed a secondary analysis of the Euro-DEN Plus Registry (14 countries, 22 EDs) which includes 17,371 consecutive patients presenting to the ED with acute recreational drug toxicity over 39 consecutive months (October 2013 - December 2016). We compared the epidemiological and clinical characteristics and ED management of patients identified as presenting with acute toxicity related to lone GHB/GBL (Group A) or GHB/GBL combined with ethanol (Group B) without other concomitant drugs.

RESULTS

A total of 609 patients were included (age 32 (8) years; 116 women (19%); Group A: 183 patients and Group B: 426). The most common features were reduction in consciousness (defined as Glasgow Coma Score <13 points: 56.1%) and agitation/aggressiveness (33.6%). Those with ethanol co-ingestion were younger patients (Group A/B: 31.5/33.1 years, p = 0.029) and ethanol co-ingestion was associated with a lower frequency of bradycardia (23.5%/15.7%, p = 0.027) and more frequent arrival at the ED by ambulance (68.3/86.6%; p < 0.001), reduction in consciousness (58.9%/49.1%; p = 0.031), need for treatment in the ED (49.2%/60.4%; p = 0.011), use of sedatives (20.1%/12.8%; p = 0.034), admission to critical care units (22.4%/55.3%; p < 0.001), and longer hospital stay (stay longer than 6 h: 16.9%/28.4%; p = 0.003).

CONCLUSIONS

Co-ingestion of ethanol increases the adverse effects of patients intoxicated by GHB/GBL, leading to greater depression of consciousness, need for treatment, admission to the ICU and longer hospital stay.

Metabolomic study of polyamines in rat urine following intraperitoneal injection of γ-hydroxybutyric acid

INTRODUCTION

Recently, illegal abuse of γ-hydroxybutyric acid (GHB) has increased in drug-facilitated crimes, but the determination of GHB exposure and intoxication is difficult due to rapid metabolism of GHB. Its biochemical mechanism has not been completely investigated. And a metabolomic study by polyamine profile and pattern analyses was not performed in rat urine following intraperitoneal injection with GHB.

OBJECTIVES

Urinary polyamine (PA) profiling by gas chromatography-tandem mass spectrometry was performed to monitor an altered PA according to GHB administration.

METHODS

Polyamine profiling analysis by gas chromatography-mass spectrometry combined with star pattern recognition analysis was performed in this study. The multivariate statistical analysis was used to evaluate discrimination among control and GHB administration groups.

RESULTS

Six polyamines were determined in control, single and multiple GHB administration groups. Star pattern showed distorted hexagonal shapes with characteristic and readily distinguishable patterns for each group. N¹-Acetylspermine (p < 0.001), putrescine (p < 0.006), N¹-acetylspermidine (p < 0.009), and spermine (p < 0.027) were significantly increased in single administration group but were significantly lower in the multiple administration group than in the control group. N¹-Acetylspermine was the main polyamine for discrimination among control, single and multiple administration groups. Spermine showed similar levels in single and multiple administration groups.

CONCLUSIONS

The polyamine metabolic pattern was monitored in GHB administration groups. N¹-Acetylspermine and spermine were evaluated as potential biomarkers of GHB exposure and addiction.

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.

Metabolism of amino acid neurotransmitters: the synaptic disorder underlying inherited metabolic diseases

Amino acids are involved in various metabolic pathways and some of them also act as neurotransmitters. Since biosynthesis of L-glutamate and γ-aminobutyric acid (GABA) requires 2-oxoglutarate while 3-phosphoglycerate is the precursor of L-glycine and D-serine, evolutionary selection of these amino acid neurotransmitters might have been driven by their capacity to provide important information about the glycolytic pathway and Krebs cycle. Synthesis and recycling of amino acid neurotransmitters as well as composition and function of their receptors are often compromised in inherited metabolic diseases. For instance, increased plasma L-phenylalanine concentrations impair cerebral biosynthesis of protein and bioamines in phenylketonuria, while elevated cerebral L-phenylalanine directly acts via ionotropic glutamate receptors. In succinic semialdehyde dehydrogenase deficiency, the neurotransmitter GABA and neuromodulatory γ-hydroxybutyric acid are elevated. Chronic hyperGABAergic state results in progressive downregulation of GABA_A and GABA_B receptors and impaired mitophagy. In glycine encephalopathy, the neurological phenotype is precipitated by L-glycine acting both via cortical NMDA receptors and glycine receptors in spinal cord and brain stem neurons. Serine deficiency syndromes are biochemically characterized by decreased biosynthesis of L-serine, an important neurotrophic factor, and the neurotransmitters D-serine and L-glycine. Supplementation with L-serine and L-glycine has a positive effect on seizure frequency and spasticity, while neurocognitive development can only be improved if treatment starts in utero or immediately postnatally. With novel techniques, the study of synaptic dysfunction in inherited metabolic diseases has become an emerging research field. More and better therapies are needed for these difficult-to-treat diseases.

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.

[Course and complications of GHB detoxification treatment: a 1-year case series]

BACKGROUND

Gamma-hydroxybutyrate (GHB) and its precursors have gained popularity over the last decade as a drug in the party and club scene; however, the clinical knowledge of these substances is low. In the literature there have been case reports of severe dependence and withdrawal but there is a lack of systematic knowledge about the clinical course and complications of detoxification treatment.

OBJECTIVE

The aim of this article is to evaluate the prevalence, treatment course, complications and compliance of GHB patients seeking inpatient qualified detoxification treatment (QDT).

METHODS

A retrospective evaluation of the hospital charts of all patients admitted to this clinic in 2017 for QDT of GHB. The Jewish Hospital in Berlin (Jüdisches Krankenhaus Berlin) provides specialized inpatient units for addictive diseases and a general intensive care unit. The control population came from a prospective study of all patients with addictive diseases who were treated in the same hospital in 2012.

RESULTS

In 2017 a total of 18 patients with GHB addiction were treated in this hospital. This corresponds to a 1‑year prevalence of 2.28% of all addictive diseases in this year. During detoxification treatment 52% of the GHB patients had to be temporarily transferred to the intensive care unit, 5% had to be temporarily mechanically ventilated and 26% suffered from withdrawal delirium. Of the patients 42% terminated treatment prematurely against medical advice.

CONCLUSION

Withdrawal treatment from GHB is a severe and potentially dangerous condition, the prevalence of complications was higher than for most other drugs and the rate of intensive care and withdrawal delirium was very high. Further studies are urgently needed with the aim of reducing the complication rates of GHB withdrawal and enhancing therapy adherence.

Designing Green Plasticizers: Linear Alkyl Diol Dibenzoate Plasticizers and a Thermally Reversible Plasticizer

Several linear alkyl diol dibenzoate compounds, ranging from C3 to C6 in central diol length, were evaluated for their plasticizing effectiveness in blends with poly(vinyl chloride) (PVC). The results were compared to blends of PVC/di(2-ethylhexyl) phthalate (DEHP), the most commonly used commercial plasticizer. DEHP has come under scrutiny, due to its suspected endocrine-disrupting behaviour, and the proposed diol dibenzoates have previously been shown to have the potential to be green, safe candidates for DEHP replacement. The thermal and mechanical properties of PVC/dibenzoate blends were determined, and include glass transition temperature (T_g), the elongation at break, maximum stress, apparent moduli, torsional modulus, and surface hardness. The C3, C5, and C6 dibenzoates performed as well as or better than DEHP, with the exception of torsional modulus, further supporting their use as green plasticizers. For blends with 1,4-butanediol dibenzoate, differential scanning calorimetry and torsional temperature sweeps suggested that the compound partly crystallizes within PVC blends over the course of two days, thereby losing the ability to effectively plasticize PVC. However, upon heating to temperatures above 60 °C, effective plasticization was again observed. 1,4-Butanediol dibenzoate is thereby a reversible heat-activated plasticizer or processing aid with excellent plasticizer properties at mildly elevated temperatures.

A continuing challenge: N-heterocyclic carbene-catalyzed syntheses of γ-butyrolactones

Catalytic, stereoselective N-heterocyclic carbene-catalyzed reactions facilitate efficient construction of many different heterocyclic compounds, such as the enantioenriched 5-membered (γ) lactones highlighted in this tutorial review. Herein, various strategies to enable formal [3+2] type annulations between electrophilic carbonyl equivalents and homoenolate nucleophiles for the synthesis of γ-lactones are summarized.

Alcohol addiction - the safety of available approved treatment options

INTRODUCTION

Alcohol Use Disorders (AUD) is a leading cause of mortality and morbidity worldwide. At present disulfiram, naltrexone and acamprosate are approved for the treatment of AUD in U.S. and Europe. Nalmefene is approved in Europe and sodium oxybate is approved in Italy and Austria only. Baclofen received a 'temporary recommendation for use' in France.

AREAS COVERED

The safety of the above mentioned medications on liver, digestive system, kidney function, nervous system, pregnancy and lactation and their possible side effects are described and discussed.

EXPERT OPINION

Mechanism of action and metabolism of these drugs as well as patients' clinical characteristics can affect the safety of treatment. All approved medications are valid tools for the treatment of AUD in patients without advanced liver disease. For some drugs, attention should be paid to patients with renal failure and medications may be used with caution, adjusting the dosage according to kidney function. In patients with AUD and advanced liver disease, at present only baclofen has been formally tested in randomized controlled trials showing its safety in this population.

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.

Treatment consumption and treatment re-enrollment in GHB-dependent patients in The Netherlands

BACKGROUND

The objective of this study was to assess treatment consumption and re-enrollment in treatment in patients with gamma-hydroxybutyrate (GHB)-dependence in Dutch Addiction Treatment Centers (ATCs) in comparison with other addictions.

METHODS

A cohort-study using nationwide administrative data from regular Dutch ATCs associated with the Dutch National Alcohol and Drugs Information System (LADIS), covering an estimated 95% of ATCs. We selected in- and out-patients with alcohol, drug and/or behavioral addictions with a first treatment episode in 2008-2011 and consecutive treatments until 2013 (n=71,679). Patients still in treatment at that date (n=3686; 5.1%), forensic patients (n=1949; 2.7%) and deceased patients (n=570; 0.8%) were excluded, leaving 65,474 patients (91.3%). Of those, 596 (0.9%) patients had GHB dependence. We analyzed number of treatment contacts, treatment duration, admissions and admission duration of the first treatment episode, and re-enrollment (defined as having started a second treatment episode in the study period).

RESULTS

GHB-dependent patients showed the highest number of treatment contacts, duration of treatment and chance of being admitted. Re-enrollment rates were 2-5 times higher in GHB-dependent patients than other patients with adjusted HR of other addictions ranging from 0.18 (95% confidence interval [CI]: 0.15-0.21) to 0.53 (95% CI: 0.47-0.61).

CONCLUSIONS

This study demonstrates high levels of treatment consumption and high rates of treatment re-enrollment in GHB-dependent patients. These findings highlight the urgency of developing effective relapse prevention interventions for GHB-dependent patients.