Deaths associated with inhalant abuse in Virginia from 1987 to 1996

Sudden death due to butane abuse - An overview

Volatile Solvents Abuse (VSA) poses major health risks, especially for young people and those living in precarious socio-economic conditions. Such substances can in fact bring about psychoactive effects such as euphoria, and even lead to sudden death from cardiac arrhythmias, respiratory depression, myocardial infarction, laryngospasm, encephalopathy, and rhabdomyolysis. The present case report is centered around a 23-year-old man who died in prison due to inhalation of a cooker gas mixture (n-butane, propane, and isobutane) inside a plastic bag. External examination and autopsy showed non-specific signs of asphyxia associated with edema and brain swelling. Histological signs of early myocardial damage and hypoxic-ischemic injury (HII) were highlighted in the brain and cerebellum, as well as activated macrophages and anthracotic-like material in the lungs. Toxicological investigations revealed the presence of propane, isobutane and n-butane in liquids and biological samples. Besides the cardiotoxic effect, there was an asphyctic component due to the plastic bag that may have facilitated death. The assessment of cerebral HII and cardiopulmonary damage in acute cases is very important to prove death by butane inhalation. In the forensic field, it may be useful to shed more light on intoxications, deaths, and butane encephalopathies, as the latter can be mistaken for a hypoxic-ischemic encephalopathy.

The Clinical Presentations of Nitrous Oxide Users in an Emergency Department

Today, the concomitant abuse of nitrous oxide (N₂O) and illicit drugs is evident and problematic. However, there are few reports regarding the clinical manifestations of N₂O users when they present to the emergency department (ED). The purpose of this study was to describe the clinical presentations, the associated illicit substances used in combination, and the outcomes in N₂O users visiting the ED. This was a retrospective observational cohort study. All N₂O adult users admitted to the ED at Linkou Chang Gung Memorial Hospital between 2012 and 2020 were included. Demographic variables, clinical symptoms, and examination results were collected from medical records. Univariate comparisons were conducted between pure N₂O users and combined illicit drug users. A total of 40 patients were included, 24 of which were pure N₂O users. Limb weakness and numbness accounted for the majority of chief complaints. Neurologic symptoms were the most common clinical manifestations (90%). A more severe ED triage level, faster heart rate, greater agitation, and cardiovascular symptoms were significantly noted in combined illicit drug users. In ED, limb numbness/weakness should arouse physicians’ awareness of patients using N₂O. Combined use of N₂O and illicit drugs can cause great harm to health.

The last two decades on preclinical and clinical research on inhalant effects

This paper reviews the scientific evidence generated in the last two decades on the effects and mechanisms of action of most commonly misused inhalants. In the first section, we define what inhalants are, how they are used, and their prevalence worldwide. The second section presents specific characteristics that define the main groups of inhalants: (a) organic solvents; (b) aerosols, gases, and volatile anesthetics; and (c) alkyl nitrites. We include a table with the molecular formula, structure, synonyms, uses, physicochemical properties and exposure limits of representative compounds within each group. The third and fourth sections review the direct acute and chronic effects of common inhalants on health and behavior with a summary of mechanisms of action, respectively. In the fifth section, we address inhalant intoxication signs and available treatment. The sixth section examines the health effects, intoxication, and treatment of nitrites. The seventh section reviews current intervention strategies. Finally, we propose a research agenda to promote the study of (a) solvents other than toluene; (b) inhalant mixtures; (c) effects in combination with other drugs of abuse; (d) age and (e) sex differences in inhalant effects; (f) the long-lasting behavioral effects of animals exposed in utero to inhalants; (g) abstinence signs and neurochemical changes after interrupting inhalant exposure; (h) brain networks involved in inhalant effects; and finally (i) strategies to promote recovery of inhalant users.

Effects of inhaled combined Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX): Toward an environmental exposure model

Combined environmental exposures to the volatile organic compounds (VOCs) Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) pose clear risks to public health. Research into these risks is under-studied even as BTEX levels in the atmosphere are predicted to rise. This review focuses on the available literature using single- and combined-BTEX component inhaled solvent exposures in animal models, necessarily also drawing on findings from models of inhalant abuse and occupational exposures. Health effects of these exposures are discussed for multiple organ systems, but with particular attention on neurobehavioral outcomes such as locomotor activity, impulsivity, learning, and psychopharmacological responses. It is clear that animal models have significant differences in the concentrations, durations and patterns of exposure. Experimental evidence of the deleterious health and neurobehavioral consequences of exposures to the individual components of BTEX were found, but these effects were typically assessed using concentrations and exposure patterns not characteristic of environmental exposure. Future studies with animal models designed appropriately to explore combined BTEX will be necessary and advantageous to discovering health outcomes and more subtle neurobehavioral impacts of long-term environmental exposures.

Cardiac arrest by inhalation of deodorant spray

Drug abuse by inhalation of volatile household product substances is uncommon, however, it can have devastating consequences. This case report describes the fatal outcome of deodorant inhalation by a 19-year-old patient in a detoxification clinic who developed a cardiac arrest after inhaling butane from a deodorant spray. Despite initial successful resuscitation, he developed a postanoxic encephalopathy with a status epilepticus resistant to extensive treatment. Inhalant abuse can be a cause of death in young patients.

Fatal butane toxicity and delayed onset of refractory ventricular fibrillation

A 30-year-old male was presented to the Emergency Department (ED) by the Emergency Medical Services (EMS). He was found unconscious but breathing normally, and had a seizure for more than 30 minutes. He was no previous history of systemic disease, previous operation, medication and any known allergy. According to the witnesses, he was alone in the coffee shop, and besides him was a lighter refill canister containing 250 ml extra purified butane gas, and he suddenly collapsed and had seizure. Six hours later, he developed ventricular fibrillation and he was not responding to amiodarone infusion, and 4 times defibrillation and cardioversion. He died after 45 minutes of resuscitation.

Participation of voltage-gated sodium and calcium channels in the acute cardiac effects of toluene

Inhaling solvents can lead to occurrence of cardiac arrhythmias and sudden sniffing death. Mechanisms related to this phenomenon are not fully understood. The purpose of this study was to investigate the effect of acute toluene exposure on heart reactivity to epinephrine and the participation of voltage-gated sodium and calcium channels. We found that acute toluene exposure increased perfusion pressure, left ventricular developed pressure, and heart rate. These actions were inhibited by lidocaine and nifedipine. Our results suggest that acute toluene exposure modify voltage-gated sodium and calcium channel function and expression likely due to a cardiac adrenergic mechanism and these effects could be participating, at least in part, in the presence of cardiac arrhythmias. To our best knowledge, this is the first report to establish a direct participation of voltage-gated Na⁺ and Ca²⁺ channels, toluene and epinephrine on cardiac function in rats.

Up: The rise of nitrous oxide abuse. An international survey of contemporary nitrous oxide use

In recent years the recreational use of inhaled nitrous oxide gas (N2O) is becoming increasingly popular, yet little is known about the characteristics of its users or the effects they experience. This paper presents original research from the 2014 Global Drug Survey (GDS) (n=74,864). GDS runs the largest survey of recreational drug use in the world. The findings confirm N2O as a very common drug of use, in particular in the UK and US (38.6% and 29.4% lifetime prevalence). In the UK N2O was reported to be the eighth most commonly used substance. N2O was generally consumed via gas-filled balloons, at festivals and clubs where use of other substances was common. The vast majority of users use infrequently, and their use is not associated with significant harm. However, there appears to be a subpopulation of heavy users who may be using in a dependent pattern. Analysis of last year N2O users (n=4883), confirms that N2O is associated with hallucinations and confusion (which may be the desired effects) and persistent numbness and accidental injury (27.8%, 23.9%, 4.3% and 1.2% of last year users, respectively). Accidental injury is associated with the highest number of 'hits' per session, suggesting a dose-response relationship. The presence of significant harm is discussed in the light of public education on the risks of N2O use and harm-reduction strategies appropriate to N2O use. Further work needs to be completed to confirm the presence of persistent neurological symptoms in recreational users.

Neurologic, psychiatric, and other medical manifestations of nitrous oxide abuse: A systematic review of the case literature

BACKGROUND/OBJECTIVES

Nitrous oxide (N2 O) is known to have abuse potential, although debate regarding the toxic effects of such abuse continues. Our objective was to review the case literature and present the neurologic, psychiatric and medical consequences of N2 O abuse.

METHODS

A systematic literature review was completed for case reports using keywords "nitrous oxide" with "abuse/abusing" or "misuse/misusing" or "overuse/overusing" or "addiction." Non-English-language cases and cases not involving direct toxic effects of N2 O were excluded as were commentaries or personal essays. Clinical presentation, frequency of N2 O abuse, laboratory studies, imaging, ancillary tests, treatments and outcomes were collected from case reports.

RESULTS

Our review returned 335 Pubmed, 204 Web of Science, 73 PsycINFO, 6 CINAHL, 55 EMBASE and 0 Grey Literature results, and after exclusion and removal of duplicates, 91 individual cases across 77 publications were included. There were also 11 publications reporting 29 cases of death related to N2 O abuse. The majority of cases (N = 72) reported neurologic sequelae including myeloneuropathy and subacute combined degeneration, commonly (N = 39) with neuroimaging changes. Psychiatric (N = 11) effects included psychosis while other medical effects (N = 8) included pneumomediastinum and frostbite. Across all cases N2 O abuse was correlated with low or low-normal Vitamin B12 (cyanocobalamin) levels (N = 52) and occasionally elevated homocysteine and methylmalonic acid.

CONCLUSIONS/SCIENTIFIC SIGNIFICANCE

N2 O abuse represents a significant problem because of the difficulty involved with identification and the toxicity related to chronic abuse including possible death. Health professionals should be aware of the toxic effects of N2 O and be able to identify potential N2 O abuse. (Am J Addict 2016;25:358-369).

Laboratory approach for diagnosis of toluene-based inhalant abuse in a clinical setting

The steady increase of inhalant abuse is a great challenge for analytical toxicologists. This review describes an overview of inhalant abuse including the extent of the problem, types of products abused, modes of administration, pharmacology and effects of inhalants, the role of laboratory, interpretation of laboratory results and clinical considerations. Regular laboratory screening for inhalant abuse as well as other substance abuse and health risk behaviors must be a part of standard clinical care.

Air Duster abuse causing rapid airway compromise

Inhalant abuse is potentially life-threatening and has resulted in many complications such as central nervous system depression, cardiac dysrhythmia and hypoxia. Inhalant abuse causing angioedema is rarely reported in the medical literature. In this report we present a case of rapidly progressive airway compromise following recreational huffing. Our patient required intubation and intensive care unit admission with complete recovery after 5 days. The aetiology of airway compromise is postulated to be due to commonly reported frost bite injury and rarely reported angioedema. To the best of our knowledge this the second case reporting angioedema secondary to huffing Air Duster.

Patterns of substance use, delinquency, and risk factors among adolescent inhalant users

BACKGROUND

Despite insidious effects, use of inhalant substances by adolescents remains an understudied phenomenon.

OBJECTIVE

This research was designed to identify patterns of past year substance use and delinquency among adolescent inhalant users.

METHOD

The study used a sample of adolescent inhalant users (ages ranged from 12-17 years, n = 7,476) taken from a pooled sample of the 2002 through 2012 National Survey of Drug Use and Health (NSDUH). Three-step latent class analyses were conducted with past year substance use and delinquency behaviors as class indicators. Demographic and social covariates were included in the analyses.

RESULTS

Analyses yielded a six-class solution comprised of classes of users characterized by low substance use/low delinquency, high substance use/low delinquency, low substance use/fighting, cigarettes/alcohol/marijuana, high substance use/high delinquency, and cigarettes/alcohol/ marijuana/opioids/moderate delinquency.

CONCLUSIONS

Findings provide insight into the taxonomy of adolescent inhalant user heterogeneity, and may inform future efforts at detection and prevention of inhalant use by suggesting warning signs of co-occurring externalizing behaviors and possible indications of underlying internalized issues.

Community Influence on Youth's Use of Inhalants and Other Legal Products to Get High in Rural Alaska

This study examines the use of inhalants and other harmful legal products (HLPs) to get high among pre-adolescents in frontier Alaska communities. Community factors that may influence use of HLPs are highlighted. This study uses secondary data from two NIH studies in 19 Alaska communities. A hierarchal generalized linear modeling technique was used to model community level effects on HLP use. The results show that lifetime use was reported by 18% of the pre-adolescents. Pre-adolescents in "dry" communities (with laws restricting alcohol use) had much higher lifetime and past 30-day HLP use. The results suggest that additional study of the relationship between use of HLPs and local laws governing availability is warranted.

Pharmacological classification of the abuse-related discriminative stimulus effects of trichloroethylene vapor

Inhalants are distinguished as a class primarily based upon a shared route of administration. Grouping inhalants according to their abuse-related in vivo pharmacological effects using the drug discrimination procedure has the potential to provide a more relevant classification scheme to the research and treatment community. Mice were trained to differentiate the introceptive effects of the trichloroethylene vapor from air using an operant procedure. Trichloroethylene is a chlorinated hydrocarbon solvent once used as an anesthetic as well as in glues and other consumer products. It is now primarily employed as a metal degreaser. We found that the stimulus effects of trichloroethylene were similar to those of other chlorinated hydrocarbon vapors, the aromatic hydrocarbon toluene and the vapor anesthetics methoxyflurane and isoflurane. The stimulus effects of trichloroethylene overlapped with those of the barbiturate methohexital, to a lesser extent the benzodiazepine midazolam and to ethanol. NMDA antagonists, the kappa opioid agonist U50,488 and the mixed 5-HT agonist mCPP largely failed to substitute for trichloroethylene. These data suggest that stimulus effects of chlorinated hydrocarbon vapors are mediated at least partially by GABA_A receptor positive modulatory effects.

Review of toluene action: clinical evidence, animal studies and molecular targets

It has long been known that individuals will engage in voluntary inhalation of volatile solvents for their rewarding effects. However, research into the neurobiology of these agents has lagged behind that of more commonly used drugs of abuse such as psychostimulants, alcohol and nicotine. This imbalance has begun to shift in recent years as the serious effects of abused inhalants, especially among children and adolescents, on brain function and behavior have become appreciated and scientifically documented. In this review, we discuss the physicochemical and pharmacological properties of toluene, a representative member of a large class of organic solvents commonly used as inhalants. This is followed by a brief summary of the clinical and pre-clinical evidence showing that toluene and related solvents produce significant effects on brain structures and processes involved in the rewarding aspects of drugs. This is highlighted by tables highlighting toluene's effect on behaviors (reward, motor effects, learning, etc.) and cellular proteins (e.g. voltage and ligand-gated ion channels) closely associated the actions of abused substances. These sections demonstrate not only the significant progress that has been made in understanding the neurobiological basis for solvent abuse but also reveal the challenges that remain in developing a coherent understanding of this often overlooked class of drugs of abuse.

Binge toluene exposure in pregnancy and pre-weaning developmental consequences in rats

Binge Toluene Exposure in Pregnancy and Pre-weaning Developmental Consequences in Rats. Bowen, S.E. and Hannigan, J.H. The persistent rate of abuse of inhaled organic solvents, especially among women of child-bearing age, raises the risk for teratogenic effects of maternal toluene abuse. In this study, timed-pregnant Sprague Dawley rats were exposed from Gestation Day (GD) 8 to GD20 to 12,000 or 8000 parts per million (ppm) toluene, or 0ppm (controls) for 30min twice daily, 60min total daily exposure. Pups were assessed from postnatal day (PN) 4 to PN21 using a developmental battery measuring growth (i.e., body weight), maturational milestones (e.g., eye opening & incisor eruption), and biobehavioral development (e.g., negative geotaxis & surface righting). Pups exposed in utero to 12,000ppm or 8000ppm toluene weighed significantly less than the non-exposed control pups beginning at PN4 and PN12 (respectively) until PN21. Toluene resulted in significant increases in an index of poor perinatal outcome, specifically a composite of malformations, defined "runting" and neonatal death. No significant delays were observed in reaching maturational milestones. The results reveal that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth retardation and malformations in rats. A comparison of the present, conservative results with findings in previous studies implies that binge patterns of toluene exposure in pregnant rats modeling human solvent abuse can result in developmental and morphological deficits in offspring. These results do not exclude the possibility that maternal toxicity as well as teratogenic effects of toluene may contribute to outcomes. The results suggest that abuse of inhaled organic solvents like toluene may result in similar early developmental outcomes in humans.

Inhalant abuse (typewriter correction fluid) in street children

BACKGROUND

: Inhalant abuse is a growing concern in India among street children.

AIM

: To describe the sociodemographic and clinical characteristics of 9 street children and adolescents with typewriter correction fluid abuse.

METHOD

: Nine street children who presented to the psychiatry department of Dr. Ram Manohar Lohia Hospital, New Delhi for treatment of inhalant abuse were interviewed.

FINDINGS

: The inhalant abusers were boys of 10 to 17 years, school dropouts who had run away from villages of Bihar and Uttar Pradesh. In two-third of children there was domestic violence and conflict in their family, along with physical abuse by family members; in one-third it was due to alcoholic fathers. They used to "huff" typewriter correction fluid, and abused other substances as well.

CONCLUSION

: There is a need to systematically study inhalant abuse in the street children in India.

GABAA-positive modulator selective discriminative stimulus effects of 1,1,1-trichloroethane vapor

BACKGROUND

The abuse-related behavioral effects of inhalant vapors are poorly understood but probably involve multiple neurotransmitter receptor mechanisms. The present study examined the receptor systems responsible for transducing the discriminative stimulus of the abused chlorinated hydrocarbon 1,1,1-trichloroethane (TCE) in mice.

METHODS

Thirty mice were trained to discriminate 10 min of 12,000 ppm TCE vapor exposure from air using an operant procedure. Substitution tests were then conduced with positive GABA(A) receptor modulators and/or NMDA receptor antagonists.

RESULTS

The nonselective benzodiazepines midazolam and diazepam produced 62% and 61% and the barbiturate pentobarbital produced 68% TCE-lever selection. Zaleplon, an alpha1 subunit-preferring positive GABA(A) receptor benzodiazepine-site positive modulator resulted in 29% TCE-lever selection. The direct extrasynaptic GABA(A) agonist gaboxodol (THIP) and the GABA reuptake inhibitor tiagabine failed to substitute for TCE. No substitution was elicited by a competitive (CGS-19755), noncompetitive (dizocilpine) or glycine-site (L701,324) NMDA antagonist. The mixed benzodiazepine/noncompetitive NMDA antagonist anesthetic Telazol and the anticonvulsant valproic acid exhibited low levels of partial substitution for TCE (38% and 39%, respectively). Ethanol and nitrous oxide failed to substitute for TCE.

CONCLUSIONS

The results suggest that the discriminative stimulus effects of TCE are fairly selectively mediated by positive modulation of GABA(A) receptors. The failure of gaboxadol to substitute and the poor substitution by zaleplon suggests that extrasynaptic GABA(A) receptors as well as GABA(A) receptors containing alpha1 subunits and are not involved in transducing the discriminative stimulus of TCE. Studies with additional GABA(A) benzodiazepine-site positive modulators will be necessary to confirm and extend these findings.

Two serious and challenging medical complications associated with volatile substance misuse: sudden sniffing death and fetal solvent syndrome

Volatile substance misuse is a prevalent and often overlooked behavior among adolescents, including reported use among young pregnant women. Several medical repercussions can arise from the improper use of volatile substances, yet they are often underappreciated among scientists and health professionals. This brief review reports on the recent advances made in the preclinical and clinical data about two serious medical complications surrounding volatile substance misuse: sudden sniffing death and fetal solvent syndrome. Suggestions for treatment interventions are discussed. The paper's limitations are noted.

Work-related cerebro-cardiovascular diseases in Korea

Cerebro-cardiovascular disease (CVD) is one of compensable occupational diseases in Korea as in Japan or Taiwan. However, most countries accept only cardiovascular diseases (ischemic heart diseases) as compensable occupational diseases if any, but not cerebrovascular diseases. Korea has a prescribed list of compensable occupational diseases. CVD was not included in the list until 1993. In the early 1990s, a case of cerebral infarction was accepted as occupational disease by the Supreme Court. The decision was based on the concept that workers' compensation system is one of the social security systems. In 1994, the government has established a diagnostic criterion of CVD. The crude rate of compensated cerebrovascular disease decreased by 60.0% from 18.5 in 2003 to 7.4 in 2008 per 100,000 workers, and that of compensated coronary heart disease decreased by 60.5% from 3.8 in 2003 to 1.5 in 2008 per 100,000 workers. The compensated cases of CVD dramatically increased and reached its peak in 2003. Since many preventive activities were performed by the government and employers, the compensated cases have slowly decreased since 2003 and sharply decreased after 2008 when the diagnostic criterion was amended. The strategic approach is needed essentially because CVDs are common, serious and preventable diseases which lead to economic burden.

Accidental deaths due to inhalant misuse in North Carolina: 2000-2008

This study describes the number and characteristics of accidental deaths associated with recreational inhalant misuse in North Carolina from 2000 to 2008. Inhalant-related deaths were identified via an electronic search of records of the North Carolina Office of the Chief Medical Examiner. Thirty deaths were attributed to recreational inhalant use, and nearly a third involved the inhalation of compressed-air products. Polydrug use and comorbid psychiatric disorders were common among decedents. The types of inhalants most often resulting in death differed from previous studies, as did the somewhat older mean age of decedents. Further research on inhalant-related mortality is warranted.

Comparison of toluene-induced locomotor activity in four mouse strains

The mechanisms by which abused inhalants exert their neurobehavioral effects are only partially understood. In research with other drugs of abuse, specific inbred mouse strains have been useful in exploring genetic loci important to variation in behavioral reactions to these drugs. In the present investigation, mice from three inbred strains (Balb/cByj, C57BL/6J and DBA/2J) and one outbred strain (Swiss Webster) were studied for their acute and chronic sensitivity to toluene-induced changes in locomotor activity. Mice were exposed to toluene (0, 100, 2000, 8000, and 10,000 ppm) for 30 min in static exposure chambers equipped with activity monitors. In the acute condition, concentrations of toluene <8000 ppm increased ambulatory distance while the concentrations of > or =8000 ppm induced temporally biphasic effects with initial increases in activity followed by hypoactivity. Between-group differences in absolute locomotor activity levels were evident. The inbred Balb/cByj and DBA/2J strains as well as the outbred Swiss Webster strain of mice showed greater increases in activity after an acute challenge exposure to 2000 ppm than the inbred C57BL/6J strain. The same animals were then exposed 30 min/day to 8000 ppm toluene for 14 consecutive days. Re-determination of responses to 2000-ppm challenge exposures revealed that sensitization developed in locomotor activity and that the DBA/2J strain showed the greatest increase in sensitivity. These baseline differences in acute sensitivity and the differential shifts in sensitivity after repeated exposures among the inbred mouse strains suggest a genetic basis for the behavioral effects to toluene. The results support the notion that like for other drugs of abuse, using various strains of mice may be useful for investigating mechanisms that underlie risk for inhalant abuse.

Preventing youths' use of inhalants and other harmful legal products in frontier Alaskan communities: a randomized trial

This study tests for the efficacy of a school-based drug prevention curriculum (Think Smart) that was designed to reduce use of Harmful Legal Products (HLPs, such as inhalants and over-the-counter drugs), alcohol, tobacco, and other drugs among fifth- and sixth-grade students in frontier Alaska. The curriculum consisted of 12 core sessions and 3 booster sessions administered 2 to 3 months later, and was an adaptation of the Schinke life skills training curriculum for Native Americans. Fourteen communities, which represented a mixture of Caucasian and Alaska Native populations in various regions of the state, were randomly assigned to intervention or control conditions. Single items measuring 30-day substance use and multi-item scales measuring the mediators under study were taken from prior studies. Scales for the mediators demonstrated satisfactory construct validity and internal reliability. A pre-intervention survey was administered in classrooms in each school in the fall semester of the fifth and sixth grades prior to implementing the Think Smart curriculum, and again in the spring semester immediately following the booster session. A follow-up survey was administered 6 months later in the fall semester of the sixth and seventh grades. A multi-level analysis found that the Think Smart curriculum produced a decrease (medium size effect) in the proportion of students who used HLPs over a 30-day period at the 6 month follow-up assessment. There were no effects on other drug use. Further, the direct effect of HLPs use was not mediated by the measured risk and protective factors that have been promoted in the prevention field. Alternative explanations and implications of these results are discussed.

Abused inhalants enhance GABA-mediated synaptic inhibition

Abused inhalants are widely used, especially among school-age children and teenagers, and are 'gateway' drugs leading to the abuse of alcohol and other addictive substances. In spite of this widespread use, little is known about the effects produced by inhalants on the central nervous system. The similarity in behavioral effects produced by inhalants and inhaled anesthetics, together with their common chemical features, prompted this study of inhalant actions on a well-characterized anesthetic target, GABA synapses. Whole-cell patch clamp recordings were conducted on CA1 pyramidal neurons in rat hippocampal brain slices to measure effects on resting membrane properties, action potential discharge, and GABA-mediated inhibitory responses. Toluene, 1,1,1-trichloroethane, and trichloroethylene depressed CA1 excitability in a concentration-dependent and reversible manner. This depression appeared to involve enhanced GABA-mediated inhibition, evident in its reversal by a GABA receptor antagonist. Consistent with this, the abused inhalants increased inhibitory postsynaptic potentials produced using minimal stimulation of stratum radiatum inputs to CA1 neurons, in the presence of CNQX and APV to block excitatory synaptic responses and GGP to block GABA(B) responses. The enhanced inhibition appeared to come about by a presynaptic action on GABA nerve terminals, because spontaneous inhibitory postsynaptic current (IPSC) frequency was increased with no change in the amplitude of postsynaptic currents, both in the presence and absence of tetrodotoxin used to block interneuron action potentials and cadmium used to block calcium influx into nerve terminals. The toluene-induced increase in mIPSC frequency was blocked by dantrolene or ryanodine, indicating that the abused inhalant acted to increase the release of calcium from intracellular nerve terminal stores. This presynaptic action produced by abused inhalants is shared by inhaled anesthetics and would contribute to the altered behavioral effects produced by both classes of drugs, and could be especially important in the context of a disruption of learning and memory by abused inhalants.

Neurochemical changes after acute binge toluene inhalation in adolescent and adult rats: a high-resolution magnetic resonance spectroscopy study

Inhalant abuse in young people is a growing public health concern. We reported previously that acute toluene intoxication in young rats, using a pattern of exposures that approximate abuse patterns of inhalant use in humans, significantly altered neurochemical measures in select brain regions. In this study, adolescent and young adult rats were exposed similarly to an acute (2 x 15 min), high dose (8000-12,000 ppm) of toluene and high-resolution magic angle spinning proton magnetic resonance spectroscopy (HR-MAS 1H-MRS) was used to assess neurochemical profiles of tissue samples from a number of brain regions collected immediately following solvent exposure. The current investigation focused on N-acetyl-aspartate (NAA), choline-containing compounds, creatine, glutamate, GABA, and glutamine. Contrary to our predictions, no significant alterations were found in the levels of NAA, choline, creatine, glutamate, or glutamine in adolescent animals. In contrast to these minimal effects in adolescents, binge toluene exposure altered several neurochemical parameters in young adult rats, including decreased levels of choline and GABA in the frontal cortex and striatum and lowered glutamine and NAA levels in the frontal cortex. One of the more robust findings was a wide-ranging increase in lactate after toluene exposure in adult animals, an effect not observed in adolescents. These age-dependent effects of toluene are distinct from those reported previously in juvenile rats and suggest a developmental difference in vulnerability to the effects of inhalants. Specifically, the results suggest that the neurochemical response to toluene in adolescents is attenuated compared to adults, and imply an association between these neurochemical differences and age-influenced differences in solvent abuse in humans.

Epidemiology of Volatile Substance Abuse (VSA) Cases Reported to US Poison Centers

Volatile substance abuse (VSA) is believed to be widespread. The Toxic Exposure Surveillance System (TESS) of the American Association of Poison Control Systems offers an opportunity to evaluate the epidemiology of volatile substance abuse using a data set that captures data from a large geographic area covering a wide-ranging group of socioeconomic strata, ethnic groups, and demographics. To utilize this potential we analyzed a data set of TESS for the 6-year period of 1996 through 2001 involving all cases of intentional inhalational abuse of nonpharmaceutical substances. Over the study period there was a mean annual decline of 9% of reported VSA with an overall decline of 37% from 1996 to 2001. Volatile substance abuse was reported primarily in children, with 6358 cases (54%) in children 13-19 yr and 1803 (15%) cases in children 6-12 yr. Fifty-two cases were reported in children < 5 or = 5 yr. A total of 2330 (20%) VSA cases had a serious outcome, defined as either moderate effect (n = 2000), major effect (n = 267), or death (n = 63). The top five categories of substances abused were gasoline (41%), paint (13%), propane/butane (6%), air fresheners (6%), and formalin (5%). Three categories were responsible for the majority of deaths: gasoline (45%), air fresheners (26%), and propane/butane (11%). While there was a decline in reported cases, there was no decline in major outcomes or fatalities. Volatile substance abuse was reported in all 50 states, with case distribution similar to population distribution. However, seven states had > 2 times the expected rate based on their population; three western states, two midwestern states, and two Appalachian states. The role of urban vs. rural population may possibly explain the difference in numbers, with a greater incidence of VSA cases reported in states with large rural populations. The mean monthly occurrence rate was 162 VSA cases/month (S.D. +/- 10.85). There were 4 months that were > 2 standard deviations from the mean, with two peak months (May, 192/month and March, 187/month) and two trough months (December, 126/month and January, 137/month). This report presents a broad picture of VSA in the United States. Volatile substance abuse, as reported to U.S. poison centers, appears to be on the decline, but continues to be an ongoing problem. Volatile substance abuse is reported throughout the U.S. in all areas of the country, with a higher incidence in states with large rural populations. A small group of substances appears responsible for the majority of deaths. It is imperative that we continue to educate the public and healthcare professionals regarding the risks of VSA and hopefully impact the incidence of VSA.

Adolescent Inhalant Use among Male Patients in Treatment for Substance and Behavior Problems: Two-Year Outcome

Adolescent inhalant users are significantly more likely than other patients to have conduct disorder, to report abuse and neglect, and to have previously attempted suicide. Yet little has been published regarding treatment outcome for inhalant users.

METHODS

Eighty male adolescents admitted to a residential treatment program underwent baseline assessment during treatment, and follow-up assessment at two-years post admission. Subjects reporting any lifetime inhalant use at baseline (n = 34) were compared to the other patients (n = 46) on 4 outcome variables.

RESULTS

Adolescents reporting any lifetime inhalant use at baseline assessment reported twice as many past-year conduct disorder symptoms at two-year follow up (p = 0.03). The relationship between inhalant use and conduct disorder symptoms remained significant (p = 0.03) in analyses that controlled for age, time in jail or restricted environments in the 6-months preceding follow-up, as well as baseline-reported lifetime number of conduct disorder symptoms. Inhalant users were not significantly worse on these other outcome measures: crime in the last month (p = 0.60), days of nontobacco substance use in the last 6 months (p = 0.65), or, commission of selected crimes in the last 6 months (p = 0.06).

CONCLUSIONS

Inhalant use among adolescent males in treatment for substance and behavior problems may predict more severe conduct disorder symptoms after treatment.

Characterization of an inhaled toluene drug discrimination in mice: effect of exposure conditions and route of administration

The drug discrimination procedure in animals has been extensively utilized to model the abuse related, subjective effects of drugs in humans, but it has seldom been used to examine abused volatile inhalants like toluene. The present study sought to characterize the temporal aspects of toluene's discriminative stimulus as well assess toluene blood concentrations under identical exposure conditions. B6SJLF1/J mice were trained to discriminate 10 min of exposure to 6000 ppm inhaled toluene vapor from air. Toluene vapor concentration dependently substituted for the training exposure condition with longer exposures to equivalent concentrations producing greater substitution than shorter exposures. Toluene's discriminative stimulus effects dissipated completely by 60 min after the cessation of exposure. Injected liquid toluene dose-dependently substituted for toluene vapor as well as augmenting the discriminative stimulus effects of inhaled toluene. Toluene blood concentrations measured under several exposure conditions which produced full substitution were all nearly identical suggesting that the concentration of toluene in the animal tissues at the time of testing determined discriminative performance. These results indicate that the discriminative stimulus effects of inhaled toluene vapor are likely mediated by CNS effects rather than by its pronounced peripheral stimulus effects.

Alterations in rat fetal morphology following abuse patterns of toluene exposure

Toluene is a commonly abused organic solvent. Inhalant abusers are increasingly women in their prime childbearing years. Children born to mothers who abused solvents during pregnancy may exhibit characteristics of a "fetal solvent syndrome" which may include dysmorphic features. This study examined the teratological effects of an abuse pattern of binge toluene exposure during gestation on skeletal and soft tissue abnormalities, body weight, and body size in fetal rats. Pregnant Sprague-Dawley rats were exposed for 30 min, twice daily, from gestational day (GD) 8 through GD20 to either air (0 ppm), 8000 ppm, 12,000 ppm, or 16,000 ppm toluene. Two-thirds of each litter was prepared for skeletal examination using Alizarin Red S staining while the remaining third of each litter was fixed in Bouin's solution for Wilson's soft tissue evaluation. Exposure to toluene at all levels significantly reduced growth, including decreases in placental weight, fetal weight, and crown-rump length. In addition, numerous gross morphological anomalies were observed such as short or missing digits and missing limbs. Skeletal examination revealed that ossification of the extremities was significantly reduced as a result of toluene exposure at all levels. Specific skeletal defects included misshapen scapula, missing and supernumerary vertebrae and ribs, and fused digits. Soft tissue anomalies were also observed at all toluene levels and there was a dose-dependent increase in the number of anomalies which included cryptorchidism, displaced abdominal organs, gastromegaly, distended/hypoplastic bladder, and delayed cardiac development, among others. These results indicate that animals exposed prenatally to levels and patterns of toluene typical of inhalant abuse are at increased risk for skeletal and soft tissue abnormalities.

Inhalant abuse

Inhalant abuse is the intentional inhalation of a volatile substance for the purpose of achieving an altered mental state. As an important, yet-underrecognized form of substance abuse, inhalant abuse crosses all demographic, ethnic, and socioeconomic boundaries, causing significant morbidity and mortality in school-aged and older children. This clinical report reviews key aspects of inhalant abuse, emphasizes the need for greater awareness, and offers advice regarding the pediatrician's role in the prevention and management of this substance abuse problem.

Region-dependent alterations in glutamate and GABA measured by high-resolution magnetic resonance spectroscopy following acute binge inhalation of toluene in juvenile rats

Little is known about the neurochemical effects accompanying the high-concentration inhalant exposures characteristic of binge solvent abuse. In adult animals, prior studies with other patterns of exposure indicate that toluene, a commonly abused household and industrial solvent, has significant effects on the glutamatergic and GABAergic neurotransmitter systems and on other neurotransmitter systems as well. In the current investigation, high-resolution "magic angle" spinning proton magnetic resonance spectroscopy (HR-MAS (1)H-MRS) was used to assess the effect of acute binge toluene inhalation on regional brain concentrations of various neurochemicals including glutamate (GLU), GABA, and glutamine (GLN) in juvenile male and female rats. Acute toluene (8000 ppm or 12,000 ppm) significantly reduced levels of hippocampal GABA (-12%) and GLU (-8%), and the GLU/GLN ratio, an index of glutamatergic tone, was significantly reduced (-22%) in the dorsal anterior striatum, driven largely by a 28% increase in GLN. Significant increases in alanine and lactate in several brain regions after acute toluene may be indicative of altered oxygen-dependent metabolism associated with the inhalation of higher concentrations of toluene (e.g., >5000 ppm). Other components of the MR-visible neurochemical profile, such as N-acetylaspartate (NAA), myo-inositol, creatine, and various choline containing compounds, were unchanged by acute toluene. The results are consistent with the notion that binge toluene exposure affects juvenile neurochemistry in systems mediating the rewarding and emotional aspects of substance abuse. Moreover the results provide a framework to understand further (1)H-MRS studies in clinical populations.

Bithalamic lesions of butane encephalopathy

Butane inhalation can cause serious medical complications and is particularly toxic to the nervous system. This is a report of an acutely encephalopathic youth with prominent abulia. MRI revealed severe bithalamic injury attributed to butane toxicity. Clinical issues, including particular radiologic findings, related to butane inhalation are reviewed.

Inhalant use and disorders among adults in the United States

OBJECTIVE

To examine the patterns of adult inhalant use and correlates of inhalant use disorder.

METHOD

We drew study data from the 2002 and 2003 National Surveys on Drug Use and Health (NSDUH). We used logistic regression to identify the characteristics associated both with inhalant use and inhalant use disorder.

RESULTS

One in 10 of all adults had used an inhalant at least once in their lives, and 0.5% used one in the past year. Among all past year inhalant users, 8% met the criteria for an inhalant use disorder (i.e., 6.6% for abuse and 1.1% for dependence) within that period. We found an increased prevalence of past year inhalant use among young adults aged 18-25 years, Asians, past year alcohol abusers and dependents, lifetime drug users, white women, and men reporting symptoms of serious mental illness. Inhalant-using adults who met the criteria for an inhalant use disorder were predominantly adults aged 35-49 years and were less educated, had received recent professional treatment for emotional or psychological problems, used inhalants weekly, and had a coexisting alcohol use disorder.

CONCLUSION

The patterns and consequences of adult inhalant use differ from those of adolescents. Compared with adolescent inhalant users, adult users tend not to initiate inhalant use until adulthood, use inhalants less frequently, use fewer inhalants, and are less likely to engage in criminal activities.

The last decade of solvent research in animal models of abuse: mechanistic and behavioral studies

The abuse of volatile organic solvents (inhalants) leads to diverse sequelae at levels ranging from the cell to the whole organism. This paper reviews findings from the last 10 years of animal models investigating the behavioral and mechanistic effects of solvent abuse. In research with animal models of inhalant abuse, NMDA, GABA(A), glycine, nicotine, and 5HT(3) receptors appear to be important targets of action for several abused solvents with emerging evidence suggesting that other receptor subtypes and nerve membrane ion channels may be involved as well. The behavioral effects vary in magnitude and duration among the solvents investigated. The behavioral effects of acute and chronic inhalant abuse include motor impairment, alterations in spontaneous motor activity, anticonvulsant effects, anxiolytic effects, sensory effects, and effects on learning, memory and operant behavior (e.g., response rates and discriminative stimulus effects). In addition, repeated exposure to these solvents may produce tolerance, dependence and/or sensitization to these effects.

Increases in amphetamine-like discriminative stimulus effects of the abused inhalant toluene in mice

RATIONALE

Toluene, an abused solvent, shares behavioral and pharmacological effects with abused depressant drugs. These effects include ethanol- and pentobarbital-like discriminative stimulus effects. There is also emerging evidence that this abused inhalant may share stimulus effects with abused central nervous system (CNS) stimulants.

OBJECTIVE

To further explore the discriminative stimulus effects of one abused inhalant, this experiment evaluated the amphetamine-like discriminative stimulus effects of toluene.

MATERIALS AND METHODS

Mice were trained to discriminate between d-amphetamine (1.0 mg/kg) and saline in a two-lever drug discrimination procedure in which responding was under the control of a fixed-ratio 15 schedule. Mice were tested after 10-min inhalation exposures to air or toluene (500-6,000 ppm) and stimulus generalization was examined at 0, 15, 30, 45, 60, and 75 min post-exposure.

RESULTS

Concentration-related increases in amphetamine-lever responding were observed for amphetamine doses >0.56 mg/kg with full substitution occurring immediately after testing for 1.0 and 1.78 mg/kg. Partial amphetamine-lever responding was observed for all concentrations of toluene across the 75-min post-exposure test trials. Response rates that had decreased immediately after all toluene exposures recovered within 15-min post exposure.

CONCLUSION

This partial substitution of toluene for amphetamine suggests that studies of the effects of abused solvents on brain dopaminergic systems need to be included in the study of possible CNS mechanisms.

Autoerotic Accident by Inhalation of Propane-Butane Gas Mixture

We present a case of an accidental autoerotic death involving the inhalation of a propane-butane gas mixture, also known as LPG (liquefied petroleum gas). A 19-year-old male was found dead in supine position in his bed in a residential accommodation one day after he was last seen alive. On a personal computer at the end of the bed, a pornographic movie was still running. On his left shoulder, an empty rubber balloon and on the bedside 2 empty "Kisag-Gas" cartridges were found. Toxicologic investigations revealed an intoxication with propane and butane, together with a recent consumption of cannabis. This case report compares the toxicologic findings with other recently published cases, and the theories of the toxic effects are discussed.

Adolescent suicide due to inhalation of insect spray

A 17-year-old female who had been expressing suicidal ideation following domestic problems was found dead in her room next to a towel and an empty can of insect spray. There were no suspicious circumstances and it appeared that the deceased had inhaled insect spray using the towel to maintain the concentration of vapour around her nose and mouth. There was no history of recreational inhalation of volatile substances or other illicit drug use. Inhalation of insect spray is a rare method of suicide in keeping with the suggestion that young suicide victims utilize unusual methods of self-destruction determined to some degree by availability and accessibility.

Abuse pattern of gestational toluene exposure and early postnatal development in rats

Inhalant abuse in the United States trails only alcohol, marijuana and nicotine abuse. Toluene, found in glues and cleaners, is among the most commonly abused inhalants. While teratogenicity due to occupational exposure to organic solvents (i.e., relatively long-term exposure to lower concentrations) has been studied, the teratogenic potential of organic solvent abuse (i.e., brief inhalation exposures to very high concentrations) has not been thoroughly examined. In a preclinical model of abuse patterns of fetal solvent exposure, timed-pregnant rats were exposed to 8000 parts per million (ppm) or 12,000 ppm of toluene, or to air (0 ppm), for 15 min twice daily from gestation day 8 (GD8) through GD20. After parturition, pups were tested from postnatal day 4 (PN4) to PN21 in a developmental test battery including measures of growth (i.e., body weight), maturational milestones (i.e., pinnae unfolding, incisor eruption and eye opening) and biobehavioral development (e.g., negative geotaxis, surface righting and grip strength). Pups exposed in utero to 12,000 ppm toluene weighed significantly less than the control pups at all ages before PN16. There were significant toluene-induced increases in an index of poor perinatal outcome (i.e., a combination of malformations, "runting" and neonatal death) and deficits in negative geotaxis. There were no significant delays in reaching maturational milestones. The results demonstrate that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth restriction, malformation and impairments of biobehavioral development in rats. A comparison of the present outcomes to previous studies of occupational exposure patterns suggests that for a given daily "dose" of toluene, a binge pattern of exposure may pose a greater risk for fetal development. Since the pattern of exposure in this experiment models binge exposure in human solvent abuse, the results imply that abuse of inhaled organic solvents, such as toluene, can cause similar teratogenic outcomes in humans.

Street and working children of Delhi, India, misusing toluene: an ethnographic exploration

Our qualitative study explored: the perceptions of street children indulging in whitener fluid misuse; the social, economic, and cultural determinants of use; and users' views regarding effective preventive and control strategies. Forty-five in-depth interviews and three focus group discussions were conducted between March and December 2003. A purposive sample of those working children who were using toluene was selected by Snowball sampling. The paper discusses the: determinants of initiation and continued use; drug user social networks; psycho emotional deprivation and frustrations of these children; socio-cultural aspects like work driven need; others' attitudinal response towards them and their work; parental support or the lack of it; and strategies for prevention of this misuse.

Inhalant abuse and dependence among adolescents in the United States

OBJECTIVE

To examine the patterns of inhalant use and correlates of the progression from inhalant use to abuse and dependence among adolescents aged 12 to 17.

METHOD

Study data were drawn from the 2000 and 2001 National Household Surveys on Drug Abuse. Multinominal logistic regression was used to identify the characteristics associated with progression to inhalant abuse and dependence.

RESULTS

Inhalant use was common among the studied adolescents. Among adolescents aged 12 to 17, 0.4% met DSM-IV inhalant abuse or dependence criteria in the past year. Inhalant abuse and dependence affected adolescents regardless of gender, age, race/ethnicity, and family income. The progression from inhalant use to abuse or dependence was related to early first use, use of multiple inhalants, and weekly inhalant use. Adolescents with inhalant use disorders reported coexisting multiple drug abuse and dependence, mental health treatment, and delinquent behaviors.

CONCLUSIONS

Adolescents with an inhalant use disorder may represent a subgroup of highly troubled youths with multiple vulnerabilities. Because early use is associated with progression to abuse and dependence, prevention programs should target elementary school-age children.