Predictors of severe outcome following opioid intoxication in children.

INTRODUCTION: While the opioid crisis has claimed the lives of nearly 500,000 in the U.S. over the past two decades, and pediatric cases of opioid intoxications are increasing, only sparse data exist regarding risk factors for severe outcome in children following an opioid intoxication. We explore predictors of severe outcome (i.e., intensive care unit [ICU] admission or in-hospital death) in children who presented to the Emergency Department with an opioid intoxication. METHODS: In this prospective cohort study we collected data on all children (0-18 years) who presented with an opioid intoxication to the 50 medical centers in the US and two international centers affiliated with the Toxicology Investigators Consortium (ToxIC) of the American College of Medical Toxicology, from August 2017 through June 2020, and who received a bedside consultation by a medical toxicologist. We collected relevant demographic, clinical, management, disposition, and outcome data, and we conducted a multivariable logistic regression analysis to explore predictors of severe outcome. The primary outcome was a composite severe outcome endpoint, defined as ICU admission or in-hospital death. Covariates included sociodemographic, exposure and clinical characteristics. RESULTS: Of the 165 (87 females, 52.7%) children with an opioid intoxication, 89 (53.9%) were admitted to ICU or died during hospitalization, and 76 did not meet these criteria. Seventy-four (44.8%) children were exposed to opioids prescribed to family members. Fentanyl exposure (adjusted OR [aOR] = 3.6, 95% CI: 1.0-11.6; p = 0.03) and age ≥10 years (aOR = 2.5, 95% CI: 1.2-4.8; p = 0.01) were independent predictors of severe outcome. CONCLUSIONS: Children with an opioid toxicity that have been exposed to fentanyl and those aged ≥10 years had 3.6 and 2.5 higher odds of ICU admission or death, respectively, than those without these characteristics. Prevention efforts should target these risk factors to mitigate poor outcomes in children with an opioid intoxication.

Gamma-Hydroxybutyrate (GHB), gamma-butyrolactone (GBL), and 1,4-butanediol (1,4-BD) reduce the volume of cerebral infarction in rodent transient middle cerebral artery occlusion.

gamma-Hydroxybutyric acid (GHB), an endogenous organic acid catabolite of gamma-aminobutyric acid (GABA), has been shown to have tissue-protective effects in various organs, including the brain. We examined the potential neuroprotective effect of GHB and its chemical precursors, gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), in the rodent ischemic stroke model by intraluminal filament middle cerebral artery occlusion (MCAO). Adult male Sprague-Dawley rats underwent transient left-sided MCAO and received intraperitoneal treatment with 300 mg/kg of GHB, GBL, 1,4-BD, or control vehicle given at 30 min before, as well as 180 and 360 min after the onset of ischemia. Infarct volumes were determined 24 h after MCAO. In transient MCAO, the mean volume of infarction for control rats was 464.4 +/- 17.9 cu.mm versus 273.6 +/- 53.1, 233.3 +/- 44.7, and 275.4 +/- 39.9 cu.mm for rats treated with 1,4-BD (P < 0.05), GBL (P < 0.05), and GHB (P < 0.05), respectively. We conclude that GHB, GBL, and 1,4-BD protect against rat focal cerebral ischemia from transient MCAO.

Evaluation for the withdrawal syndrome from gamma-hydroxybutyric acid (GHB), gamma-butyrolactone (GBL), and 1,4-butanediol (1,4-BD) in different rat lines.

A severe and life-threatening gamma-hydroxybutyric acid (GHB) withdrawal syndrome, clinically similar to the alcohol withdrawal syndrome, is increasingly being reported in GHB addicts. We investigated for the occurrence of withdrawal in Wistar and Sprague-Dawley rats, and in the selectively bred lines of GHB-sensitive (GHB-S) and Sardinian alcohol-preferring (sP) rats, following chronic administration of GHB, gamma-butyrolactone (GBL), and/or 1,4-butanediol (1,4-BD). Using validated rodent alcohol withdrawal scoring scales, little to no spontaneous or pharmacologically precipitated withdrawal effects were observed in Wistar, Sprague-Dawley, or GHB-S rats. Conversely, sP rats displayed both spontaneous and precipitated audiogenic seizures following abrupt cessation of chronic GHB or 1,4-BD administration and following pharmacological challenge with the GABA(B) receptor-selective antagonist, SCH 50911, respectively.

Metabolism of gamma-hydroxybutyrate to d-2-hydroxyglutarate in mammals: further evidence for d-2-hydroxyglutarate transhydrogenase.

gamma-Hydroxybutyratic acid (GHB), and its prodrugs 4-butyrolactone and 1,4-butanediol, represent expanding drugs of abuse, although GHB is also used therapeutically to treat narcolepsy and alcoholism. Thus, the pathway by which GHB is metabolized is of importance. The goal of the current study was to examine GHB metabolism in mice with targeted ablation of the GABA degradative enzyme succinic semialdehyde dehydrogenase (SSADH(-/-) mice), in whom GHB persistently accumulates, and in baboons intragastrically administered with GHB immediately and persistently. Three hypotheses concerning GHB metabolism were tested: (1) degradation via mitochondrial fatty acid beta-oxidation; (2) conversion to 4,5-dihydroxyhexanoic acid (a putative condensation product of the GHB derivative succinic semialdehyde); and (3) conversion to d-2-hydroxyglutaric acid (d-2-HG) catalyzed by d-2-hydroxyglutarate transhydrogenase (a reaction previously documented only in rat). Both d-2-HG and 4,5-dihydroxyhexanoic acid were significantly increased in neural and nonneural tissue extracts derived from SSADH(-/-) mice. In vitro studies demonstrated the ability of 4,5-dihydroxyhexanoic acid to displace the GHB receptor ligand NCS-382 (IC(50) = 38 micromol/L), although not affecting GABA(B) receptor binding. Blood and urine derived from baboons administered with GHB also accumulated d-2-HG, but not 4,5-dihydroxyhexanoic acid. Our results indicate that d-2-HG is a prominent GHB metabolite and provide further evidence for the existence of d-2-hydroxyglutarate transhydrogenase in different mammalian species.

Resuscitative treatments on 1,4-butanediol mortality in mice.

STUDY OBJECTIVE: Recent reports on fatalities associated with overdoses from 1,4-butanediol (1,4-BD), a precursor of the drug of abuse gamma-hydroxybutyric acid (GHB), pose the need for investigations focusing on possible pharmacologic remedies. Accordingly, the present study investigates whether 4-methylpyrazole (4-MP; also termed fomepizole and Antizol), an inhibitor of alcohol dehydrogenase (the enzyme involved in the first step of the conversion of 1,4-BD into GHB), and the gamma-aminobutyric acid B (GABAB) receptor antagonist (2S)(+)-5,5-dimethyl-2-morpholineacetic acid (SCH 50911), provides protection against 1,4-BD-induced mortality in CD1 mice. METHODS: Two sets of experiments were conducted with mortality as the outcome measure. In all experiments, mice were initially treated with a lethal dose of 1,4-BD (3 g/kg, intragastric [i.g.]). In the first set of experiments (dose-response curves), once mice had displayed clear signs of 1,4-BD intoxication, animals were randomly allocated in separate groups (n=10) and treated acutely with either 4-MP (vehicle, 3, 10, 30, and 100 mg/kg, intraperitoneal [i.p.]) or SCH 50911 (vehicle, 75, 150, and 300 mg/kg, i.p.). Mortality was recorded every hour for the first 9 hours and 12, 18, and 24 hours after 1,4-BD injection. In the second set of experiments (time course), mice were randomly allocated in separate groups (n=10). A single dose of either 4-MP (30 mg/kg, i.p.) or SCH 50911 (150 mg/kg, i.p.) was administered 15, 30, 60, 90, or 120 minutes after administration of 3 g/kg 1,4-BD (i.g.). Again, mortality was recorded every hour for the first 9 hours and 12, 18, and 24 hours after 1,4-BD injection. RESULTS: In the dose-response experiments, the acute administration of 4-MP and SCH 50911 exerted a dose-dependent resuscitative effect in mice acutely intoxicated by 3 g/kg 1,4-BD. Specifically, 30 and 100 mg/kg 4-MP and 150 mg/kg SCH 50911 protected all treated mice against 1,4-BD-induced mortality. Conversely, all mice treated with 4-MP- and SCH 50911-vehicle died. In the time-course experiments, protection induced by 30 mg/kg 4-MP was complete when administered up to 90 minutes after 1,4-BD injection. Vice versa, the complete protection induced by 150 mg/kg SCH 50911 progressively diminished as the time between 1,4-BD and SCH 50911 administration was increased from 15 to 120 minutes. CONCLUSION: These results indicate that both 4-MP and SCH 50911 protected against mortality induced by 1,4-BD. Further, these results suggest that 1,4-BD-induced mortality in mice is a result of conversion of 1,4-BD into GHB and GHB-induced activation of the GABAB receptor. Because both 4-MP and GABAB receptor antagonists are available for human use, clinical studies on their ability to reverse the consequences of 1,4-BD and GHB intoxication, including fatal events, might be considered.

Withdrawal syndrome from gamma-hydroxybutyric acid (GHB) and 1,4-butanediol (1,4-BD) in Sardinian alcohol-preferring rats.

Gamma-hydroxybutyric acid (GHB) and its precursors, 1,4-butanediol (1,4-BD) and gamma-butyrolactone (GBL), are recreational drugs widely abused in the US, Europe and Australasia. A severe withdrawal syndrome from GHB, 1,4-BD and GBL has been increasingly documented over the last years, necessitating the development of a reliable animal model for investigations of potential therapeutic approaches. The present study describes the induction and occurrence of audiogenic seizures as a sign of withdrawal from GHB and 1,4-BD in selectively bred Sardinian alcohol-preferring (sP) rats, treated with escalating doses of GHB (1.5-3.5 g/kg, twice daily; i.g.) or 1,4-BD (500-1000 mg/kg, twice daily; i.g.) for 9 consecutive days. Acute administration of the selective GABA(B) receptor antagonist, SCH 50911, dramatically increased seizure occurrence. We propose that the inherent sensitivity of sP rats to different GHB-associated responses may have contributed to the unraveling of a phenomenon which was otherwise not recognizable in other rat strains.

4-methylpyrazole decreases 1,4-butanediol toxicity by blocking its in vivo biotransformation to gamma-hydroxybutyric acid.

1,4-Butanediol (1,4-BD), a prodrug converted in vivo to gamma-hydroxybutyric acid by alcohol dehydrogenase, has resulted in life-threatening overdoses and deaths. We investigated whether 4-methylpyrazole (4-MP), an alcohol dehydrogenase antagonist, can be used as an antidote in a murine model of 1,4-BD overdose. CD-1 mice were overdosed with 1,4-BD, 600 mg/kg i.p. Mice then received 4-MP, 25 mg/kg i.p., or control injections after 1 min, 5 min, and symptom appearance. Mice were then evaluated for toxicity by the righting reflex and rotarod test every 10 min after intervention. When 4-MP was administered 1 and 5 min after 1,4-BD overdose, mice completely maintained their righting reflex. Conversely, control mice lost their righting reflex for 110 and 130 min, respectively (P < 0.05). When 4-MP was administered after symptomatic 1,4-BD overdose, mice lost their righting reflex but recovered it by 60 min. Conversely, control mice lost their righting reflex and recovered it by 140 min (P < 0.05). When 4-MP was administered at 1 min after 1,4-BD overdose, mice never failed the rotarod test. Conversely, control mice failed the rotarod test for 210 min (P < 0.05). When 4-MP was administered 5 min after 1,4-BD and after symptomatic 1,4-BD overdose, mice failed the rotarod test for 100 and 110 min, respectively. Conversely, control mice failed the rotarod test for 210 and 180 min, respectively (P < 0.05). In addition, treatment of mice with 4-MP significantly attenuated increases in blood gamma-hydroxybutyric acid concentrations and prevented loss of the righting reflex and failure of the rotarod test. In this murine model of 1,4-BD overdose, 4-MP conferred antidotal effects by inhibiting alcohol dehydrogenase-mediated biotransformation of 1,4-BD to gamma-hydroxybutyric acid.

Enzyme and receptor antagonists for preventing toxicity from the gamma-hydroxybutyric acid precursor 1,4-butanediol in CD-1 mice.

1,4-Butanediol (1,4-BD), the diol alcohol precursor of gamma-hydroxybutyric acid (GHB), undergoes in vivo enzymatic biotransformation to GHB by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase. The subsequent metabolite, GHB, is pharmacologically active at GABA(B) and GHB receptors. GHB can be metabolized in vivo to gamma-aminobutyric acid (GABA) and trans-4-hydroxycrotonic acid (T-HCA), which are also pharmacologically active at GABA(B) receptors and GHB receptors, respectively. Therefore, we speculate that 1,4-BD overdose toxicity can be prevented or attenuated with the ADH enzyme inhibitor 4-methylpyrazole (4-MP) as well as with CGP-35348 and NCS-382, novel high-affinity receptor antagonists of GABA(B) receptors and GHB receptors, respectively. In our murine model of acute 1,4-BD overdose, pretreatment of CD-1 mice with 4-MP significantly attenuated increases in blood GHB concentrations and prevented loss of the righting reflex and failure of the rotarod test. Also, pretreatment with CGP-35348 and its combination with NCS-382 significantly decreased the duration of failure for the rotarod test and the percentage of animals failing the rotarod test, respectively. However, pretreatment of CD-1 mice with NCS-382 alone produced prolonged failure of the rotarod test, an unexpected synergistic effect with 1,4-BD and presumably GHB, which has not previously been demonstrated.