Popping and snorting volatile nitrites: a current fad for getting high

'Poppers Maculopathy' and the adverse ophthalmic outcomes from the recreational use of alkyl nitrate inhalants: a systematic review

OBJECTIVE

The aim of this systematic review and meta-analysis was to provide an overview of reported cases of poppers maculopathy and a statistical analysis of the clinical presentations, anatomical changes and treatment and follow-up of the rare disease.

METHODS

A systematic search of CINAHL, Embase and PubMed databases was conducted, including a search of the grey literature. Data were pooled to provide a summary of the clinical characteristics and outcomes of poppers maculopathy. Studies were critically appraised using the Joanna Briggs Institute or the Authority, Accuracy, Coverage, Objectivity, Date, Significance checklists.

RESULTS

Of the 493 articles obtained, 32 were included, consisting of 113 participants with a mean age of 40.2. Most patients were male with bilateral maculopathy and presented with either vision loss or a visual disturbance. Cessation of popper use was the most common form of management prescribed. The mean VA at baseline was 0.22 (logMAR units). For those followed-up, the mean VA significantly improved from 0.24 to 0.11 (Z = -5.800, p = <0.001). Bilateral yellow foveal spots were viewed on fundoscopy in 53 patients, and a sub-foveal disturbance of the ellipsoid layer was reported on spectral domain optical coherence tomography in 89 patients. By 6 months, SD-OCT anatomical changes mostly improved or resolved.

CONCLUSION

Recreational users of poppers who develop maculopathy generally present with vision loss or a visual disturbance secondary to foveal disruption. Patients have a good visual prognosis, with cessation of poppers potentially having a role in improved outcomes. With the high prevalence of use among gay and bisexual men, awareness of related maculopathy and presenting symptoms by clinicians is important to mitigate side effects.

Association of nitrite inhalants use and unprotected anal intercourse and HIV/syphilis infection among MSM in China: a systematic review and meta-analysis

Background

Nitrite inhalant use is very common among men who have sex with men (MSM) in China. However, there is lack of national representative data on use among Chinese MSM, and the mechanism of how nitrite inhalant use impacts HIV infection in MSM is unclear. This meta-analysis aims to understand the characteristics of Chinese MSM nitrite inhalant users and to determine the associations between nitrite inhalant use and sexual behaviors, the prevalence of HIV, and the prevalence of syphilis.

Methods

We searched PubMed, Web of Science, Chinese National Knowledge Infrastructure, Chinese Wanfang Data, and VIP Chinese Journal Database for relevant literature published from January 1985 to December 2017.

Results

Fifteen eligible studies, with a total of 18,981 Chinese MSM participants, were included. Compared with nitrite inhalant nonusers, users were more likely to be younger, have a higher level of education, and seek sexual partners using the Internet. Nitrite inhalant users were more likely to engage in high-risk sexual behaviors, including condomless anal intercourse (odds ratio [OR] = 1.33), group sex (OR = 2.26), and commercial intercourse (OR = 1.50). Nitrite inhalants users had a higher prevalence of HIV (OR = 1.83), higher prevalence of syphilis (OR = 1.38) and had higher lifetime HIV testing rates (OR = 1.33) compared with nonusers (each p < 0.05).

Conclusions

Nitrite inhalant users have higher HIV and syphilis prevalence by increasing levels of high-risk sexual behaviors. China should expand HIV testing, treatment as prevention (TasP), and Pre-exposure prophylaxis (PrEP) among MSM, especially among nitrite inhalants using MSM, to reduce their risk of HIV infection and transmission.

Multimodal imaging of a patient with poppers maculopathy

Objective: To describe the findings and the imaging characteristics of a patient with poppers maculopathy.

Methods: The ocular findings were evaluated with fundus autofluorescence imaging, spectral optical coherence tomography and optical coherence tomography angiography.

Results: A 36-year-old man presented with a history of blurring vision after using poppers. Best-corrected visual acuity was 0.9 and intraocular pressure was normal in both eyes. Fundus examination revealed hyperreflective appearence at macula with a faint foveolar reflex. Optical coherence tomography revealed focal hyperreflectivity and irregularity of the ellipsoid zone at the fovea. Fundus autofluorescence was normal. Optical Coherence Tomography Angiography revealed no vascular changes. The patient received hyperbaric oxygen therapy for 10 days. After one month VA increased, and OCT improved.

Conclusion: Inhalation of poppers may be associated with bilateral vision loss due to the disruption of photoreseptors which is clearly demonstrated with OCT.

Poppers, queer sex and a Canadian crackdown: Examining the experiences of alkyl nitrite use among young sexual minority men

BACKGROUND

Poppers (i.e., alkyl nitrites) are commonly used during sex by gay, bisexual, and other men who have sex with men (sexual minority men). Poppers act as vasodilators when inhaled, resulting in a sensation some users refer to as a 'head rush', while also relaxing smooth muscles and facilitating penetration during anal sex. In 2013, Health Canada initiated a crackdown on poppers products. The current study aims to examine the experiences and perspectives of young sexual minority men who use poppers in the context of the federal crackdown.

METHODS

We draw on 50 semi-structured, in-depth interviews collected from 2018 to 2019 in Vancouver with sexual minority men ages 15-30. We used a combination of both inductive and deductive techniques during data analysis to identify several key themes.

RESULTS

Participants' discussions reflected positive effects of poppers use relating to sexual pleasure and bodily control. Participants used poppers to enhance pleasure, reduce pain and injury (e.g., from tears in anal tissue), and improve their capacity to "let go" and enjoy sex. Conversely, some participants described a loss of control resulting from poppers use, including experiences of dependency on poppers for sexual pleasure. Poppers were also discussed as linked to participants' personal identities as sexual minority men. In the context of the federal crackdown, uncertainty about the health effects of poppers use was high, while knowledge to safely and comfortably procure poppers in Canada was, at times, low.

CONCLUSION

Poppers play an important role in the experience of sexual pleasure and the ability to reduce harms during anal sex. Unfortunately, the current crackdown restricts access to a safe and regulated supply while creating uncertainty and confusion about poppers use. We call on the federal government to bring the voices of sexual minority men to the forefront in the revisiting of the federal crackdown on poppers in Canada.

The prevalence of visual symptoms in poppers users: a global survey

Introduction and aims

The use of ‘poppers’ (volatile alkyl nitrites) has been associated with the development of visual symptoms secondary to the development of maculopathy. There are currently no data regarding the prevalence of this condition among poppers users. The aim of this study was to quantify the presence of visual symptoms among poppers users from a global cohort.

Design and methods

The Global Drug Survey (GDS) conducts annual anonymous online surveys of drug and alcohol use. Within the 2012 GDS, questions were inserted regarding the presence of visual symptoms in poppers users.

Results

The GDS received a total of 21 575 valid responses, with a total of 17 479 from the UK, Australia, USA and Eurozone. Within these areas, 5152 (29.5%) had used poppers within their lifetime and 1322 (7.6%) within the previous year. Of the ‘last year’ users, when asked the question: ‘Do you think poppers use has affected your eyesight?’, 29 (2.2%) people responded ‘yes’, 130 (10.0%) responded ‘maybe’ and 1146 (87.8%) responded ‘no (17 people did not answer). Both multiple choice and free-text responses regarding the nature of visual symptoms correlated with the central visual disturbance that would be expected from maculopathy. There was significant increased symptom prevalence with age (likelihood ratio (χ²)=19.0; p<0.001).

Discussion and conclusions

This study demonstrates that a small, yet significant from a public health perspective, proportion of poppers users have visual symptoms. Clinical correlation is required to determine whether these reported symptoms are due to poppers associated maculopathy, or an alternative cause.

Adverse ophthalmic reaction in poppers users: case series of 'poppers maculopathy'

BACKGROUND

Poppers are a recreational substance of abuse belonging to the alkyl nitrite family of compounds. In the United Kingdom, where they are legal to purchase but illegal to sell for human consumption, 10% of the general population have tried them. They are considered low risk to physical and mental health. Two recent case series from France demonstrated foveal pathology in individuals associated with poppers use.

METHOD

A case series of seven patients presenting to four hospitals in the United Kingdom with visual impairment and maculopathy associated with inhalation of poppers.

RESULTS

All patients experienced visual symptoms associated with poppers use. The majority had impaired visual acuity, central scotomata, distortion, or phosphenes. Clinical signs on fundoscopy ranged from normal foveal appearance to yellow, dome-shaped lesions at the foveola. Spectral domain optical coherence tomography (SD-OCT) showed varying degrees of disruption of the presumed inner segment/outer segment (IS/OS) junction.

DISCUSSION

Although poppers have been in use for several decades, in 2007, following legislative changes, there was a change in the most commonly used compound from isobutyl nitrite to isopropyl nitrite. There were no reports of 'poppers maculopathy' before this. Poppers maculopathy may be missed if patients are not directly questioned about their use. The disruption or loss of the presumed IS/OS junction on SD-OCT are a characteristic feature. Further study of maculopathy in poppers users is now needed. Raising public awareness of the ocular risks associated with their use may be necessary.

Noninvasive in vivo monitoring of methemoglobin formation and reduction with broadband diffuse optical spectroscopy

We present noninvasive, quantitative in vivo measurements of methemoglobin formation and reduction in a rabbit model using broadband diffuse optical spectroscopy (DOS). Broadband DOS combines multifrequency frequency-domain photon migration (FDPM) with time-independent near infrared (NIR) spectroscopy to quantitatively measure bulk tissue absorption and scattering spectra between 600 nm and 1,000 nm. Tissue concentrations (denoted by brackets) of methemoglobin ([MetHb]), deoxyhemoglobin ([Hb-R]), and oxyhemoglobin ([HbO2]) were determined from absorption spectra acquired in "real time" during nitrite infusions in nine pathogen-free New Zealand White rabbits. As little as 30 nM [MetHb] changes were detected for levels of [MetHb] that ranged from 0.80 to 5.72 microM, representing 2.2 to 14.9% of the total hemoglobin content (%MetHb). These values agreed well with on-site ex vivo cooximetry data (r2= 0.902, P < 0.0001, n = 4). The reduction of MetHb to functional hemoglobins was also carried out with intravenous injections of methylene blue (MB). As little as 10 nM changes in [MB] were detectable at levels of up to 150 nM in tissue. Our results demonstrate, for the first time, the ability of broadband DOS to noninvasively quantify real-time changes in [MetHb] and four additional chromophore concentrations ([Hb-R], [HbO2], [H2O], and [MB]) despite significant overlapping spectral features. These techniques are expected to be useful in evaluating dynamics of drug delivery and therapeutic efficacy in blood chemistry, human, and preclinical animal models.

Poppers: epidemiology and clinical management of inhaled nitrite abuse

Commonly referred to as "poppers," inhaled nitrites have a long history of abuse. Poppers are rapid-onset, short-acting potent vasodilators that produce a rush characterized by warm sensations and feelings of dizziness. Poppers sometimes are used to facilitate anal intercourse because of their actions on the anal sphincter. Epidemiologically, the frequent use of nitrites by men who have sex with men has led some experts to implicate these chemicals in the pathogenesis of Kaposi's sarcoma and acquired immunodeficiency syndrome. Controlled clinical trials to examine this potential correlation have not been conducted, and the use of nitrites simply may be a marker for other high-risk behaviors such as unprotected sex. Although regulated in the United States, many nitrite compounds and isomers are sold at various venues including bars, bookstores, and over the Internet. Adverse effects associated with these products vary from mild allergic reactions to life-threatening methemoglobinemia. The potential for drug-drug interactions and a propensity toward unsafe sex also exist. Clinicians should be familiar with the populations most likely to abuse these agents and with the clinical effects and management guidelines for acute ingestions.

Reduction of organic nitrites to nitric oxide catalyzed by xanthine oxidase: possible role in metabolism of nitrovasodilators

Xanthine oxidase (XO) was shown to catalyze the reduction of isoamyl and isobutyl nitrites to nitric oxide (NO) in the presence of xanthine under anaerobic conditions. NO was produced at a stoichiometric ratio of 2:1 versus urate generation, steady-state analysis of which showed Michaelis-Menten kinetics with xanthine as varied substrate and substrate inhibition with varied organic nitrite. Under the conditions of NO generation from isoamyl nitrite, XO was progressively inactivated by a mechanism involving conversion of Mo=S to Mo=O, yielding "desulfo" enzyme. It is proposed that XO is involved in the metabolism of organic nitrites to NO in vivo and that the observed inactivation serves to explain the phenomenon of tolerance.

Relationship between pharmacokinetics and hemodynamic effects of inhaled isobutyl nitrite in conscious rats

Our objective was to examine the pharmacokinetic/hemodynamic properties of inhaled isobutyl nitrite (ISBN) in rats. ISBN is one of the volatile organic nitrites that has been used primarily as a drug of abuse. Recent studies indicate, however, that these compounds may be superior to organic nitrates for cardiovascular use because they do not produce vascular tolerance. Rats inhaled ISBN over an exposure range of 20 to 1200 ppm for 1 hour. The effects of ISBN on blood pressure and heart rate were determined and blood concentrations of ISBN were analyzed with use of gas chromatography. Apparent steady-state blood levels of ISBN were achieved during inhalation and were linear with exposure concentration (blood concentration: 0.05 to 3.5 microM; exposure concentration: 23 to 1177 ppm; r2= 0.92). Inhaled ISBN caused rapid, dose-dependent, and parallel reductions in systolic and diastolic pressure, while heart rate increased maximally to 22%. A sigmoid Emax model could describe the mean arterial pressure effect of inhaled ISBN (Emax= 55%; EC50= 0.51 microM). After inhalation, blood pressure and heart rate quickly returned to baseline, without any withdrawal rebound effect. Inhaled ISBN produced a rapid onset of action on heart rate and blood pressure, and these effects were sustained over 60 minutes of exposure. Abrupt drug withdrawal did not lead to hemodynamic rebound. The blood pressure effects were related to ISBN blood concentration by the sigmoid Emax model. These results provide new information on the pharmacokinetic/pharmacodynamic relationship of a representative nitrite inhalant.

Analysis of isobutyl nitrite inhalant in rat and human blood: application for pharmacokinetic investigations

Organic nitrites have been used therapeutically for the treatment of angina pectoris and as diagnostic agents for the evaluation of cardiac heart murmurs. In addition, these highly volatile vasodilators are being used as inhalant drugs of abuse. We developed a gas chromatographic assay using electron capture detection for the analysis of a representative nitrite inhalant, isobutyl nitrite (ISBN), in rat and human whole blood. Unconventional sampling and processing techniques were required because of the high volatility and chemical instability of nitrites in biological fluids. Our method produced a mean recovery of ISBN from rat blood of about 86% over a concentration range of 1.0 to 400 ng/ml. The inter-day coefficient of variation was below 15% at the lowest quantifiable concentration of 1 ng/ml ISBN in rat blood. In this report, we applied the analytical method to obtain new pharmacokinetic information about ISBN. Results show that rats inhaling 900 ppm ISBN for 45 min produced steady-state blood concentrations of about 290 ng/ml, and a rapid elimination half-life of 1.4 min.

Neural basis of inhalant abuse

It should be apparent from this review that far less is known about the neural basis for inhalant abuse than for other forms of drug abuse. This reflects a lack of research interest in this area (Balster, 1997). Indeed, conclusions are difficult to draw. In the case of the volatile alkyl nitrites, the most reasonable hypothesis at this time is that the cellular basis for their abuse resides in their actions on smooth muscles to produce vasodilation and relaxation, however, direct effects on the brain cannot be ruled out. Although there is some evidence that analgesic effects of nitrous oxide may involve opiate systems, even this conclusion is controversial. There is no evidence that opiate systems play a role in nitrous oxide intoxication or reinforcement. The mechanisms for these effects are unknown. They may reflect the same actions on lipid membranes or on hydrophobic sites on unspecified proteins that have been proposed as mechanisms for nitrous oxide anesthesia. In the case of the volatile solvents, fuels and anesthetics we are faced with a wide variety of specific chemicals which may produce different profiles of pharmacological effects. There is evidence that the prototypic abused solvents toluene and trichloroethane produce acute effects similar to subanesthetic concentrations of general anesthetics, as well as to the effects of classical CNS depressant drugs, such as alcohol and the barbiturates. For the anesthetics, evidence suggests that enhancement of GABAergic inhibition may be an important cellular target for their acute effects, just as it is for alcohol and other depressant drugs. For toluene, as with alcohol, recent evidence suggests a possible role for inhibition of glutamatergic neurotransmission involving NMDA receptors. Toluene has also been shown to have some dopaminergic effects which may be important to its abuse. As for the large number of other abused vapors, practically no information can be found on their cellular actions, and certainly not on actions that may be relevant to their abuse. This entire area would seem an important direction for future research.

Solvent-free sample preparation by headspace solid-phase microextraction applied to the tracing of n-butyl nitrite abuse

The most common alkyl nitrites encountered in forensic toxicology are iso-butyl, n-butyl and iso-pentyl(amyl) nitrites. All have become popular as an aphrodisiac, especially among the homosexual population. Alkyl nitrites are a volatile and unstable group of compounds, which hydrolyse in aqueous matrices to the alcohol and nitrite ion. Here we describe a fast, clean and sensitive procedure for the detection of hydrolysed n-butyl nitrite in whole human blood using a new, solvent-free sampling technique, the headspace solid-phase micro-extraction (HSPME), combined with GC/FID analysis. Sample preparation was investigated using two different stationary phases (100 microns polydimethylsiloxane and 85 microns polyacrylate), coating a fused silica fibre. The effect of different sampling times at fixed temperatures was also studied. Our results demonstrate that the HSPME/GC/FID procedure allows tracing of n-butyl nitrite abuse and detects hydrolysed n-butyl nitrite, i.e., released n-butanol, in whole blood at the 1 ng/mL level.

Microsomal formation of S-nitrosoglutathione from organic nitrites: possible role of membrane-bound glutathione transferase

The formation of S-nitrosoglutathione (GSNO) from amyl nitrite and n-butyl nitrite was studied in rat liver microsomes, employing N-ethylmaleimide (MalNEt) as an activator and indomethacin as an inhibitor of microsomal glutathione S-transferase (GST). Rates were compared with GST activity measured with 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate. MalNEt stimulated GST activity and the formation of GSNO from amyl nitrite and n-butyl nitrite about 10-fold. Increasing concentrations of indomethacin inhibited both reactions in parallel. N-Acetyl-L-cysteine but not L-cysteine could substitute for GSH. It is concluded that rat liver microsomal GST catalyses the formation of GSNO from amyl nitrite and n-butyl nitrite. The activity of the MalNEt-stimulated microsomal GST is calculated to be about 17 units/mg of enzyme with the alkyl nitrites and about 16 units/mg of enzyme with CDNB as a substrate, assuming that 3% of microsomal protein is GST. These rates are comparable with those obtained for cytosolic GSTs. Thus microsomal GST may play a significant role in the metabolism of alkyl nitrites in biological membranes.

Human glutathione transferase catalysis of the formation of S-nitrosoglutathione from organic nitrites plus glutathione

The kinetics of spontaneous and human glutathione transferase catalysed formation of S-nitrosoglutathione (GSNO) from glutathione (GSH) and n-butyl- or amyl nitrite have been studied. At physiological pH and temperature, k2 values of 22.3 and 21.0 M-1.min-1 were obtained for n-butyl- and amyl nitrites, respectively. Rate enhancements, (kcat/Km x k2) x 10(-4), due to purified human GSH transferases A1-1, A2-2 and M1a-1a were, respectively, 7.00, 2.94 and 10.6 for n-butyl nitrite and 121, 3.92 and 34.5 for amyl nitrite. GSH transferase P1-1 showed no detectable catalysis of the formation of GSNO. The data suggest that the presence of GSTs A1-1, A2-2 or M1-1 contribute substantially to intracellular metabolism of alkyl nitrites to GSNO. The results may be significant with regard to the immunotoxicity of alkyl nitrites.

Fatal methemoglobinemia due to inhalation of isobutyl nitrite

Isobutyl nitrite is a popular recreational drug among both homosexuals and heterosexuals as it is alleged to enhance sexual pleasure and prolong orgasm. In contrast to the ingestion of this volatile nitrite, inhalation is associated only rarely with serious sequelae, though symptomatic methemoglobinemia may occur. The case reported is the first documented fatality from inhalation of isobutyl nitrite. The widespread use of isobutyl nitrite is a cause for concern and physicians should be aware of the potentially fatal consequence of abuse, particularly in those with ischemic heart disease, and its management.

S-nitrosyl glutathione-mediated hepatocyte cytotoxicity

1. The addition of n-butyl nitrite (BN) to isolated rat hepatocytes caused rapid S-nitrosyl glutathione (GSNO) formation, then a concomitant decrease in protein thiols, followed by a marked ATP depletion. Cytotoxic concentrations of BN also caused lipid peroxidation after a long lag period but before cytotoxicity ensued. 2. Prior glutathione (GSH) depletion protected hepatocytes against the BN-induced decrease in protein thiols, ATP depletion, lipid peroxidation and cytotoxicity. Thus cytotoxic effects were thought to be mediated via GSNO formed by reaction of BN with GSH, a reaction catalysed by the cytosolic fraction. 3. Cytotoxicity and lipid peroxidation, but not depletion of GSH, protein thiols or ATP, could be averted by the subsequent addition of antioxidants or the iron chelator, desferoxamine. 4. Addition of the thiol reductant, dithiothreitol to BN-treated hepatocytes restored GSH and protein thiols and also prevented cytotoxicity.

Volatile substance abuse

Volatile substance abuse has been reported in the literature over the past 20 years or so, and has apparently increased as countries have become more industrialised. This review attempts to clarify trends in volatile substance abuse, problems associated with this behaviour and possible solutions. Data sources included a Medline Search on volatile substance abuse over the last five years, Commonwealth publications, recent State and Territory inhouse publications, three research monographs from the National Institute on Drug Abuse (NIDA) and an article library from the author's workplace. Some 250 articles and monographs were identified, reviewed and categorised into sections relating to epidemiology (including mortality), physiological effects and responses to the problem. Articles were used for reference where they reflected the most up-to-date information or where they were seen as authoritative statements. While the body of knowledge concerning volatile substance abuse has improved, little progress has been made in finding effective solutions to the problem. The fact that users are typically young and that there is a real risk of sudden death associated with even initial use suggests that continuing research is needed to develop innovative approaches to the problem.

Nitrite inhalants: patterns of abuse in Baltimore and Washington, D.C

Nitrite inhalants, as drugs of abuse, have received a new prominence in the literature since their use has been associated with Kaposi's Sarcoma and possibly other manifestations of acquired immunodeficiency syndrome (AIDS). Changes in patterns and prevalence of use have not been investigated since the onset of the AIDS epidemic. We have examined the abuse patterns of nitrite inhalants (poppers) in several different groups. The use of poppers among drug abusers in the Baltimore-Washington, D.C. metropolitan area has remained constant over the past 5 years, with the prevalence of use being approximately 11% for recreational drug users and 22% for heavy abusers. Self-reported use by a homosexual group had decreased over the same time period. Sixty-nine percent of the homosexual sample had experience with nitrities, but only 21% had used them in the 6 months prior to being surveyed. The mean interval since last use was 25 months, and since peak use, 4.1 years. Among substance abusers, nitrites appear to be a drug whose use starts late, with the mean age of first use being 25.6 years compared to 14.6 years for glue, 17.6 years for marijuana, and 18.5 years for heroin. We found both heterosexual and homosexual groups utilize nitrites primarily to "get high," but homosexuals more often use them during overt sexual activity. Experience with amyl nitrite was much more prevalent than that with the butyl derivative in both populations. We conclude that the prevalence of nitrite abuse among drug users has not changed as a result of the AIDS epidemic, but such use appears to have decreased within the homosexual community.

Massive hemolysis following inhalation of volatile nitrites

Volatile nitrites are drugs which have become widely used for their mood-altering and aphrodisiac effects. Their use has been associated with methemoglobinemia and mild hemolysis; more significant hemolysis has been noted in a patient with G6PD deficiency. We report here a case of massive hemolysis following inhalation of volatile nitrites in the absence of an apparent intrinsic red cell defect. It is important that health care workers are aware of side effects from these commonly abused substances.

Trauma and other noninfectious problems in homosexual men

Homosexual men are at risk for problems unique to their sexual orientation, and the management of even standard problems must often be altered. The recognition and management of problems related to the anorectum, breasts, and external genitalia in homosexual men are discussed.

Uptake of inhaled n-butyl nitrite and in vivo transformation in rats

The uptake of butyl nitrite by rats (500 g, one rat/chamber) was determined over a 5-min exposure period. About 44% of the starting amount (771-3855 ppm) of n-butyl nitrite was consumed in 5 min. Three rats per exposure concentration were individually studied for 0-150 min after exposure. Concentrations of blood methemoglobin and plasma nitrate, nitrite, butyl nitrite, and butyl alcohol were examined. No free nitrite ion or butyl nitrite was detectable in the plasma at any time (6.5-150 min) following the exposure. Concentrations at 6.5 min of butyl alcohol, nitrate ion, and methemoglobin increased with increasing exposure concentrations. Plasma concentrations of butyl alcohol were detectable only briefly at 6.5 and 20 min. Methemoglobin levels decreased linearly at higher concentrations and as an approximate first-order process at lower concentrations (less than 15 g/L of whole blood). By 20 min after the inhalation period, plasma nitrate concentrations had decreased from peak levels to higher than baseline steady-state nitrate concentrations. Nitrosothiols were not detectable in the plasma protein fraction.

Subchronic toxicology of butyl nitrites in mice by inhalation

Mice were exposed by inhalation to n-butyl, iso-butyl sec-butyl or tert-butyl nitrite in a dynamic airflow chamber 7 h per day for 60 days at concentrations that caused less than 20% fatalities. Under these conditions, body-weight gain was depressed over the first 30 days by all four compounds, but returned to normal over the final 30 days for all compounds except tert-butyl nitrite. Spleen weights were increased by all four butyl nitrites, and lung weights were increased by all except sec-butyl nitrite. Kidney weights were increased by iso-butyl and sec-butyl nitrites, but decreased by the tert-butyl compound. Liver weights were increased by iso-butyl nitrite exposure and decreased by tert-butyl nitrite exposure. The results are consistent with the hypothesis that a significant aspect of butyl nitrite toxicity is due to the resultant methemoglobinemia.

Volatile nitrites. Use and adverse effects related to the current epidemic of the acquired immune deficiency syndrome

Early reports of the acquired immune deficiency syndrome (AIDS) in homosexual men suggested that the cause might be related to homosexual life-style practices, including use of recreational drugs. Inhalation of volatile nitrites is a possible contributing factor in AIDS because their pharmacologic properties lead to toxicity. Metabolism of N-nitroso compounds produces mutagens, teratogens, and potent carcinogens in 39 different animal species, and volatile nitrites have deleterious effects on human lymphocytes in vitro and in vivo. In relation to the current AIDS epidemic, the timing of production and sales of volatile nitrites for recreational use is the only new life-style factor that might answer the question "why AIDS now?" Prevalence of nitrite use among male homosexuals is very high, and almost every reported case of Kaposi's sarcoma during the past three years includes a history of prior nitrite use. The age of the group of patients in whom Kaposi's sarcoma and AIDS are developing is consistent with a cohort initially exposed seven to 10 years ago. Cessation of nitrite use could reduce the epidemic.

Abusing the volatile organic chemicals

Intentional inhalation of volatile organic chemicals is not a new phenomenon. It has existed since ancient times. Abusing household and other commercially available products, containing volatile organic solvents, has been recognized since the early 1950s. Products containing volatile organic chemicals include everything ranging from gasoline to paints, aerosolized foods, cosmetics, and other solvent-based household products. These products are easily available, legal, and usually inexpensive when compared to the alternative, illegal substances. While inhalant abuse is small when compared to the abuse of other substances, the problem can, in some cases, be fatal to the abuser. The public sector, industry, and government all are trying to find a solution. This paper reviews the history of perverted use of commercial products, the inhalant abuser, the signs and symptoms, the pharmacotoxicology, and the various approaches to solutions.

Subchronic inhalation toxicity of isobutyl nitrite in BALB/c mice. I. Systemic toxicity

The effects of subchronic inhalation exposure to isobutyl nitrite (IBN) on body weight, selected organ weights, hematology, and gross pathology and histopathology of BALB/c mice were evaluated. Mice of both sexes were exposed at 0, 20, 50, or 300 ppm IBN for 6.5 h/d, 5 d/wk for up to 18 wk. Most changes in measured indices occurred in mice exposed at 300 ppm IBN and included decreased thymus weight (females); decreased liver weight (males); decreased white blood cell counts (males); mild focal hyperplasia and vacuolization of the epithelium lining bronchi and bronchioles of the lungs (males and females). Organ weight and hematologic changes, however, were not accompanied by any observed histologic changes. In addition, elevated methemoglobin concentrations were detected in mice of both sexes exposed at 50 and 300 ppm IBN. Body weights were not adversely affected by exposure. These data suggest that mild tissue injury, restricted to the lung, and methemoglobinemia are the major toxic effects observed following exposures of mice to IBN at concentrations up to 300 ppm for 18 wk. No treatment-related effects were noted in mice exposed at 20 or 50 ppm IBN, except for slight elevations in methemoglobin concentrations in mice exposed at 50 ppm.

Recreational drugs: relationship to AIDS

Current data suggest that a transmissible agent causes AIDS, but undefined cofactors may also play a role. This paper reviews published data on the relationship between recreational drugs and immune alterations, with particular emphasis on nitrite inhalant (NI) use by homosexual men. In our original cohort of 15 homosexual men, helper:suppressor (H:S) T-cell ratios are stable, but persistently lower in the NI users. A recent analysis of 245 homosexual men shows that NI use is associated with low H:S ratios in homosexual men in Washington, D.C., but not in New York. Although NI use could increase the risk of AIDS by direct or indirect effects, it could also be a surrogate for a lifestyle practice that predisposes homosexual men to the putative AIDS agent. The current evidence concerning use of NI and the risk of AIDS is inconclusive, as is true for two other recreational drugs, heroin and cocaine. Future studies may not be able to dissect the complex interrelationships of drug use and other variables until precise laboratory tests are available for defining exposure to the putative AIDS agent and suspect cofactors.

Toxicity, immunosuppressive effects and carcinogenic potential of volatile nitrites: possible relationship to Kaposi's sarcoma

Volatile nitrite in the form of amyl nitrite was used for 100 years for the treatment of angina pectoris. In spite of recognized toxicity, its use in this form was considered safe. During the 1960s prescriptions were not required for purchase of amyl nitrite (called poppers) and its use for recreational purposes became popular. With reinstatement of the prescription requirement in 1969, non-medicinal, street-variety volatile nitrites were made commercially available in the form of mixtures of impure butyl and isobutyl nitrite; some of these preparations also included amyl nitrite. These products have been found to be profoundly immunosuppressive for human lymphocytes in vitro, and their by-products when metabolized into N-nitroso compounds have been known to be highly carcinogenic in many animal species. Recreational use of inhaled volatile nitrites is prevalent among male homosexuals and the compounds have been suspected as possible cofactors in Kaposi's sarcoma associated with the Acquired Immune Deficiency Syndrome (AIDS). This association could be explained by nitrite-induced vasodilation of rectal mucosal vessels providing a port of entry for a transmissible agent, by direct immunosuppression of the host allowing expression of a potentially oncogenic virus by co-carcinogenic effects of by-products by themselves or in conjunction with other putative cofactors such as cytomegalovirus. Nitrites should continue to be considered as a possible cofactor in the etiology of Kaposi's Sarcoma among male homosexuals and possibly those with other manifestations of AIDS.

Community-acquired opportunistic infections and defective cellular immunity in heterosexual drug abusers and homosexual men

Fourteen previously healthy young patients with unusual community-acquired opportunistic infections were seen over a period of three years. They differ from patients previously described in that 11 were heterosexual drug abusers (including two women) and only three were homosexual men. There were eight Puerto Ricans, five blacks, and one white. Infections included Pneumocystis carinii pneumonia (seven), disseminated Mycobacterium intracellulare infection, histoplasmosis, cryptococcosis, and cytomegalovirus infection (one each), oral thrush (13), and Candida esophagitis (two). All patients had impaired cellular immunity manifested by cutaneous anergy and lymphopenia, and all 11 tested had a markedly decreased ratio of T helper/inducer cells to T suppressor/cytotoxic cells. Twelve had evidence of associated viral infection (Epstein-Barr virus in nine, cytomegalovirus in five, Herpes simplex type 2 in two). Clinical presentation was with a severe opportunistic infection or with a prodrome consisting of oral thrush and nonspecific findings including malaise, fever, lymphadenopathy, or cough. The syndrome of immunodeficiency and opportunistic infection occurs in nonwhite heterosexual drug abusers, not exclusively in white homosexual men, and patients may present for medical care before the onset of a severe opportunistic infection.

Amyl nitrite may alter T lymphocytes in homosexual men

To evaluate the recent outbreak of Kaposi's sarcoma (KS) and opportunistic infections in homosexual men, clinical, virological, and immunological data on two homosexual men with KS and on fifteen healthy homosexual volunteers were collected. Both KS patients had regularly used amyl or butyl nitrite (AN); they had low helper/suppressor (H/S) T-lymphocyte ratios before chemotherapy and high titres of antibody against cytomegalovirus (CMV). Eight of the fifteen volunteers were regular AN users; seven of the eight had low H/S ratios due to larger than normal numbers of OKT8-positive suppressor cells and smaller numbers of OKT4-positive helper cells. In all eight AN users the fluorescence profile obtained with monoclonal antibody 9.6 (which detects the sheep E-rosette receptor) was bimodal, indicating a subpopulation of T cells with increased receptor density. A similar pattern was observed when OKT8, the antibody which detects cytotoxic suppressor cells, was used. Two of the seven men who did not use AN had abnormal fluorescence with reagent 9.6, and one of these also had a low H/S ratio. CMV-antibody titres were persistently high in fourteen of the fifteen healthy men, but the titres were not related to AN use of T-cell abnormalities. The data suggest that nitrites may be immunosuppressive in the setting of repeated viral antigenic stimulation and may contribute to the high frequency of DS and opportunistic infections in homosexual men.

Pharmacosexology: the effects of drugs on sexual function a review

The literature on the sexual side effects of drugs and chemicals has been reviewed. There are many substances which alter the human sociosexual response cycle either negatively, positively or both. Many of the drugs used therapeutically have been reported to have adverse effects on sexuality, and this must be taken into account when these drugs are used clinically. Many substances which are used for recreational purposes (or sometimes abused) also have profound effects on sexual response. Many of these substances are used in such a way that they can correct underlying sexual problems. Treatment of a drug abuser may well prove unsuccessful without consideration of preexistent sociosexual problems and concerns. From the dawn of recorded history, many substances have been used for the purpose of sexual enhancement. Some of these have known success and their reputations have been passed down through the millenia. The chapter has not yet been closed on aphrodisiacs, even though none have survived the rigors of scientific scrutiny. As long as humans place value on optimal sexual functioning, there will be a demand for sex-enhancing drugs. In order for the scientific and medical community to successfully meet these challenges, more effective and relevant study designs will have to be utilized in order to separate fact from fancy. The study of pharmacosexology is in its infancy, and in order for it to grow and contribute to the world body of knowledge, more researchers and clinicians must be trained in both pharmacology and sexology.