Blood GHB concentrations and results of medical examinations in 25 car drivers in Norway

Comprehensive evaluation of the pharmacological and toxicological effects of γ-valerolactone as compared to γ-hydroxybutyric acid: Insights from in vivo and in silico models

Γ-valerolactone (GVL), marketed online as "Tranquilli-G" and "excellent Valium", is used as a legal substitute for γ-hydroxybutyric acid (GHB); however, until now, GVL has only been connected to one Drug-Facilitated Sexual Assault (DFSA) case. Moreover, the pharmaco-toxicological effects of GVL are poorly studied. The aim of this study was to investigate the 1) in vivo effects of gavage administration of GVL (100-3000 mg/kg) on neurological (myoclonia, convulsions), sensorimotor (visual, acoustic, and overall tactile) responses, righting reflex, thermoregulation, motor activity (bar, drag, and accelerod test) and cardiorespiratory changes (heart rate, breath rate, oxygen saturation, and pulse distension) in CD-1 male mice and the 2) in silico ADMET profile of GVL in comparison to GHB and the open active form γ-hydroxyvaleric acid (GHV). The present study demonstrates that GVL inhibits, in a dose-dependent manner, sensorimotor and motor responses and induces cardiorespiratory depression (at a dose of 3000 mg/kg) in mice. The determination of the ED50 in sensorimotor and motor responses revealed that GVL is about 4-5 times less potent than GHB. In silico prediction of ADMET profiles revealed toxicokinetic similarities between GHB and GHV, and differences with GVL. These results suggest that GVL could be used as a substitute for GHB and should be added to forensic toxicology screenings.

Comparison of N-methyl-2-pyrrolidone (NMP) and the "date rape" drug GHB: behavioral toxicology in the mouse model

N-methyl-2-pyrrolidone (NMP) and γ-hydroxybutyrate acid (GHB) are synthetic solvents detected in the recreational drug market. GHB has sedative/hypnotic properties and is used for criminal purposes to compromise reaction ability and commit drug-facilitated sexual assaults and other crimes. NMP is a strong solubilizing solvent that has been used alone or mixed with GHB in case of abuse and robberies. The aim of this experimental study is to compare the acute pharmaco-toxicological effects of NMP and GHB on neurological signs (myoclonia, convulsions), sensorimotor (visual, acoustic, and overall tactile) responses, righting reflex, thermoregulation, and motor activity (bar, drag, and accelerod test) in CD-1 male mice. Moreover, since cardiorespiratory depression is one of the main adverse effects related to GHB intake, we investigated the effect of NMP and GHB on cardiorespiratory changes (heart rate, breath rate, oxygen saturation, and pulse distension) in mice. The present study demonstrates that NMP inhibited sensorimotor and motor responses and induced cardiorespiratory depression, with a lower potency and efficacy compared to GHB. These results suggest that NMP can hardly be used alone as a substance to perpetrate sexual assault or robberies.

Characteristics of patients with analytically confirmed γ-hydroxybutyric acid/γ-butyrolactone (GHB/GBL)-related emergency department visits in Taiwan

The recreational drug γ-hydroxybutyric acid (GHB) is a central nervous system depressant, and can produce euphoria at low doses. GHB is a controlled substance in Taiwan. However, the organic solvents γ-butyrolactone (GBL) and 1,4-butanediol (BD), which are unregulated, may be used as an alternative source of GHB. There is no clinical report of analytically confirmed GHB use in Taiwan. We retrospective reviewed the clinical characteristics from the medical charts between May 2017 and April 2020. The urine samples of patients presented to the emergency departments with drug-related complaints were sent for toxicological analysis. Patients with urine samples detected GHB >10 μg/mL by liquid chromatography/tandem mass spectrometry were included. Overall, 11 men and one woman with an average age of 35.3 ± 8.7 years were included. Most patients co-ingested amphetamine (n = 6) and initially presented with depressed consciousness levels (n = 7). One patient presented with out-of-hospital cardiac arrest and one with respiratory depression. All patients regained consciousness within 6 h of admission. All patients used GBL to evade conviction. Although patients recovered with supportive care, respiratory failure and cardiac arrest occurred after GHB/GBL use. It is important to legislate GBL and BD as controlled chemical substances in Taiwan.

Therapeutic Strategies for Mitigating Driving Risk in Patients with Narcolepsy

Narcolepsy is a central nervous system hypersomnia disorder characterized by uncontrollable episodes of daytime sleep, sleep state instability, and cataplexy (sudden loss of muscle tone precipitated by emotion). Individuals with narcolepsy report more frequent sleep-related crashes, near crashes, and drowsy driving than drivers with other sleep disorders. As such, evaluating risk of sleep-related crashes is of great importance for this patient population. There are no established guidelines for ensuring driving safety in patients with narcolepsy; however, many providers currently use a combination of subjective report, report of prior crashes or near-misses, report of previously falling asleep while driving, sleepiness screening tools, and maintenance of wakefulness testing (MWT) to determine risk. Driving simulator tests, though often unavailable to the clinician, provide data to support the use of MWT for evaluation of alertness in drivers with narcolepsy. Treatments such as modafinil may improve driving performance; however, the impact of other treatments such as stimulants and sodium oxybate on driving has not been extensively studied. Behavioral and lifestyle modifications may also reduce risk, including scheduled naps, driving only short distances, and avoiding driving after meals, sedating medications, and alcohol intake. Even with effective treatment, alertness in patients with narcolepsy may never reach that of normal drivers; however, studies have suggested that narcolepsy patients may be able to drive safely with appropriate limitations.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

The prevalence of gamma-hydroxybutyrate (GHB) in motor vehicle drivers and its co-administration with amphetamine type substances (ATS) in Queensland, Australia (2011-2018)

The routine analysis of driver specimens for gamma-hydroxybutyrate (GHB) is rarely performed by toxicology laboratories as the physical and chemical properties of GHB make it unamenable to the screening methods usually employed. The prevalence of the drug in driver populations has therefore only rarely been reported. This study outlines the results of the routine analysis for GHB in the blood of motor vehicle drivers in Queensland, Australia, over an eight-year period (2011-2018). The methodology for GHB analysis was updated over the course of the study; screening for GHB was conducted using GC/FID or GC/MS between 2011 and 2016 and by LC/MS/MS from 2017 onwards. Due to the endogenous nature of GHB, any specimens containing greater than 5mg/kg GHB were subjected to quantitative analysis by either; GC/MS after liquid-liquid extraction and derivatisation with BSTFA+1%TMCS (2011-2016), or by LC/MS/MS analysis after solvent precipitation from 2017 onwards. Of the 15,061 specimens analysed, 160 were positive for GHB (1.1% of all cases, range 0.4-1.8%). GHB positive drivers were 66.9% male (33.1% female) and had an average age of 32 years. The mean GHB concentration identified was 89mg/kg (range 6-354mg/kg). GHB was found to be closely associated with amphetamine type substances (ATS), particularly methylamphetamine. Though GHB was present in only 2.2% of all ATS positive specimens submitted to the laboratory, 91.2% of all GHB positive cases contained an ATS. Other drugs commonly co-administered with GHB were THC, cocaine, benzodiazepines and erectile dysfunction drugs. GHB was found to be more commonly identified in drivers from city areas and a geographical localisation of the use of the drug was identified in the Gold Coast region of Queensland.

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.

Cognitive effects of labeled addictolytic medications

INTRODUCTION

Alcohol, tobacco, and illegal drug usage is pervasive throughout the world, and abuse of these substances is a major contributor to the global disease burden. Many pharmacotherapies have been developed over the last 50years to target addictive disorders. While the efficacy of these pharmacotherapies is largely recognized, their cognitive impact is less known. However, all substance abuse disorders are known to promote cognitive disorders like executive dysfunction and memory impairment. These impairments are critical for the maintenance of addictive behaviors and impede cognitive behavioral therapies that are regularly administered in association with pharmacotherapies. It is also unknown if addictolytic medications have an impact on preexisting cognitive disorders, and if this impact is modulated by the indication of prescription, i.e. abstinence, reduction or substitution, or by the specific action of the medication.

METHOD

We reviewed the cognitive effects of labeled medications for tobacco addiction (varenicline, bupropion, nicotine patch and nicotine gums), alcohol addiction (naltrexone, nalmefene, baclofen, disulfiram, sodium oxybate, acamprosate), and opioid addiction (methadone, buprenorphine) in human studies. Studies were selected following MOOSE guidelines for systematic reviews of observational studies, using the keywords [Cognition] and [Cognitive disorders] and [treatment] for each medication.

RESULTS

971 articles were screened and 77 studies met the inclusion criteria and were reported in this review (for alcohol abuse, n=21, for tobacco n=22, for opioid n=34. However, very few comparative clinical trials have explored the chronic effects of addictolytic medications on cognition in addictive behaviors, and there are no clinical trials on the cognitive impact of nalmefene in patients suffering from alcohol use disorders.

DISCUSSION

Although some medications seem to enhance cognition in patients suffering from cognitive disorders, others could promote cognitive impairments, and our work highlights a lack of literature on this subject. In conclusion, more comparative clinical trials are needed to better understand the cognitive impact of addictolytic medications.

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.

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

INTRODUCTION

Gamma-hydroxybutyrate (GHB) and its precursors, gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), are drugs of abuse which act primarily as central nervous system (CNS) depressants. In recent years, the rising recreational use of these drugs has led to an increasing burden upon health care providers. Understanding their toxicity is therefore essential for the successful management of intoxicated patients. We review the epidemiology, mechanisms of toxicity, toxicokinetics, clinical features, diagnosis, and management of poisoning due to GHB and its analogs and discuss the features and management of GHB withdrawal.

METHODS

OVID MEDLINE and ISI Web of Science databases were searched using the terms "GHB," "gamma-hydroxybutyrate," "gamma-hydroxybutyric acid," "4-hydroxybutanoic acid," "sodium oxybate," "gamma-butyrolactone," "GBL," "1,4-butanediol," and "1,4-BD" alone and in combination with the keywords "pharmacokinetics," "kinetics," "poisoning," "poison," "toxicity," "ingestion," "adverse effects," "overdose," and "intoxication." In addition, bibliographies of identified articles were screened for additional relevant studies including nonindexed reports. Non-peer-reviewed sources were also included: books, relevant newspaper reports, and applicable Internet resources. These searches produced 2059 nonduplicate citations of which 219 were considered relevant.

EPIDEMIOLOGY

There is limited information regarding statistical trends on world-wide use of GHB and its analogs. European data suggests that the use of GHB is generally low; however, there is some evidence of higher use among some sub-populations, settings, and geographical areas. In the United States of America, poison control center data have shown that enquiries regarding GHB have decreased between 2002 and 2010 suggesting a decline in use over this timeframe.

MECHANISMS OF ACTION

GHB is an endogenous neurotransmitter synthesized from glutamate with a high affinity for GHB-receptors, present on both on pre- and postsynaptic neurons, thereby inhibiting GABA release. In overdose, GHB acts both directly as a partial GABA(b) receptor agonist and indirectly through its metabolism to form GABA.

TOXICOKINETICS

GHB is rapidly absorbed by the oral route with peak blood concentrations typically occurring within 1 hour. It has a relatively small volume of distribution and is rapidly distributed across the blood-brain barrier. GHB is metabolized primarily in the liver and is eliminated rapidly with a reported 20-60 minute half-life. The majority of a dose is eliminated completely within 4-8 hours. The related chemicals, 1,4-butanediol and gamma butyrolactone, are metabolized endogenously to GHB. CLINICAL FEATURES OF POISONING: GHB produces CNS and respiratory depression of relatively short duration. Other commonly reported features include gastrointestinal upset, bradycardia, myoclonus, and hypothermia. Fatalities have been reported. MANAGEMENT OF POISONING: Supportive care is the mainstay of management with primary emphasis on respiratory and cardiovascular support. Airway protection, intubation, and/or assisted ventilation may be indicated for severe respiratory depression. Gastrointestinal decontamination is unlikely to be beneficial. Pharmacological intervention is rarely required for bradycardia; however, atropine administration may occasionally be warranted. WITHDRAWAL SYNDROME: Abstinence after chronic use may result in a withdrawal syndrome, which may persist for days in severe cases. Features include auditory and visual hallucinations, tremors, tachycardia, hypertension, sweating, anxiety, agitation, paranoia, insomnia, disorientation, confusion, and aggression/combativeness. Benzodiazepine administration appears to be the treatment of choice, with barbiturates, baclofen, or propofol as second line management options.

CONCLUSIONS

GHB poisoning can cause potentially life-threatening CNS and respiratory depression, requiring appropriate, symptom-directed supportive care to ensure complete recovery. Withdrawal from GHB may continue for up to 21 days and can be life-threatening, though treatment with benzodiazepines is usually effective.

Long-term stability of GHB in post-mortem samples and samples from living persons, stored at -20°C, using fluoride preservatives

PURPOSE

Reanalyses are frequently requested in forensic toxicology, and knowledge of the stability of drugs in biological samples is of major importance for the interpretation of the toxicological findings. Currently, the literature on stability of gammahydroxybutyrate (GHB) in blood samples from living subjects and in post-mortem blood is limited. The purpose of this study was to evaluate the long-term stability of GHB in both blood samples from persons suspected of drug use and post-mortem blood samples.

METHODS

A total of 59 reanalyses were performed in whole blood samples, 27 samples from living subjects and 32 samples taken at autopsies. The samples were stored in the freezer between 0.4 and 7.2 years at -20°C in vials containing preservatives. Analyses were performed by GC-FID, and cut-off level was 10.3 mg/L. The concentrations in 22 of the samples were below cut-off.

RESULTS

The mean change in concentration between initial analysis and reanalysis was -0.8% for the positive samples from living persons and -7.1% for the positive post-mortem samples. Changes ranged from -32.4% to 21.0% for samples from living and from -30.4% to 34.4% for post-mortem samples. All negative samples were still negative at the time of reanalysis.

CONCLUSION

Reanalysis of these forensic whole blood samples stored several years at -20°C with fluoride preservation did not exhibit changes in GHB concentrations of practical significance for the interpretation of toxicological findings.

Determination of γ-hydroxybutyrate (GHB), β-hydroxybutyrate (BHB), pregabalin, 1,4-butane-diol (1,4BD) and γ-butyrolactone (GBL) in whole blood and urine samples by UPLC-MSMS

The demand of high throughput methods for the determination of gamma-hydroxybutyrate (GHB) and its precursors gamma-butyrolactone (GBL) and 1,4-butane-diol (1,4BD) as well as for pregabalin is increasing. Here we present two analytical methods using ultra-high pressure liquid chromatography (UPLC) and tandem mass spectrometric (MS/MS) detection for the determination of GHB, beta-hydroxybutyrate (BHB), pregabalin, 1,4BD and GBL in whole blood and urine. Using the 96-well formate, the whole blood method is a simple high-throughput method suitable for screening of large sample amounts. With an easy sample preparation for urine including only dilution and filtration of the sample, the method is suitable for fast screening of urine samples. Both methods showed acceptable linearity, acceptable limits of detection, and limits of quantification. The within-day and between-day precisions of all analytes were lower than 10% RSD. The analytes were extracted from matrices with recoveries near 100%, and no major matrix effects were observed. Both methods have been used as routine screening analyses of whole blood and urine samples since January 2010.

[Abuse of γ-hydroxybutyrate]

BACKGROUND

Gamma-hydroxybutyrate (GHB) is naturally present in the human body, but may also be used as an intoxicating drug. Information from several sources has suggested its increased availability and use in Norway. There have also been reports of an increasing use of the chemical precursor gamma-butyrolactone (GBL).There is currently a need for knowledge on symptoms, addictiveness and overdoses, as well as targeted preventive measures.

MATERIAL AND METHODS

The article is based on a discretionary selection of articles resulting from a literature search in PubMed, as well as reports from Norwegian and European authorities and research institutions.

RESULTS

An intake of small amounts of GHB produces an intoxicating effect, whereas higher doses can result in poisoning. Deaths have been reported. The effect may be variable, due to a steep dose-response curve and interaction with alcohol and other intoxicants. Treatment of poisoning is symptomatic and supportive. Treatment of abstinence is also supportive, while delirium may be treated as delirium tremens.

INTERPRETATION

Preventive measures should be tailored specifically to potential user-groups.