First injection of ketamine among young injection drug users (IDUs) in three U.S. cities

Proteomic Characteristics of the Prefrontal Cortex and Hippocampus in Mice with Chronic Ketamine-Induced Anxiety and Cognitive Impairment

Schizophrenia, a complex psychiatric disorder with diverse symptoms, has been linked to ketamine, known for its N-methyl-D-aspartate (NMDA) receptor antagonistic properties. Understanding the distinct roles and mechanisms of ketamine is crucial, especially regarding its induction of schizophrenia-like symptoms. Recent research highlights the impact of ketamine on key brain regions associated with schizophrenia, specifically the prefrontal cortex (PFC) and hippocampus (Hip). This study focused on these regions to explore proteomic changes related to anxiety and cognitive impairment in a chronic ketamine-induced mouse model of schizophrenia. After twelve consecutive days of ketamine administration, brain tissues from these regions were dissected and analyzed. Using tandem mass tag (TMT) labeling quantitative proteomics techniques, 34,797 and 46,740 peptides were identified in PFC and Hip, corresponding to 5,668 and 6,463 proteins, respectively. In the PFC, a total of 113 proteins showed differential expression, primarily associated with the immuno-inflammatory process, calmodulin, postsynaptic density protein, and mitochondrial function. In the Hip, 129 differentially expressed proteins were screened, mainly related to synaptic plasticity proteins and mitochondrial respiratory chain complex-associated proteins. Additionally, we investigated key proteins within the glutamatergic synapse pathway and observed decreased expression levels of phosphorylated CaMKII and CREB. Overall, the study unveiled a significant proteomic signature in the chronic ketamine-induced schizophrenia mouse model, characterized by anxiety and cognitive impairment in both the PFC and Hip, and this comprehensive proteomic dataset may not only enhance our understanding of the molecular mechanisms underlying ketamine-related mental disorders but also offer valuable insights for future disease treatments.

Overdoses and deaths related to the use of ketamine and its analogues: a systematic review

Background: Although the misuse of ketamine constitutes a worldwide issue, ketamine is quickly taking its place as a therapeutic option in the management of several mental disorders. However, the use of ketamine and/or its analogues, as well as combinations with other drugs, can be fatal.Objective: To outline the cases of overdoses and deaths related to the use of ketamine and/or its analogues, as reported in the scientific literature. To investigate if ketamine is safe in a therapeutic context, particularly in its use as an antidepressant.Methods: Electronic searches were performed on three medical databases. Articles describing cases of overdose and/or death associated with ketamine and/or its analogues were included. After the removal of duplicates, title analysis and full-text analysis, 34 articles were included in this review.Results: Eighteen articles described fatal cases and sixteen described overdoses. Poly-substance use was mentioned in 53% of the selected articles. Most cases were males and the ages varied from two to 65 years old. A total of 312 overdose cases and 138 deaths were reported. In both death reports and overdose cases, ketamine was preponderant: 89.1% and 79%, respectively. No cases of overdose or death related to the use of ketamine as an antidepressant in a therapeutic setting were found; most of the deaths occurred in the circumstances of polydrug use and overdoses left no sequelae.Conclusion: There is legitimate concern about the risks involving the use of ketamine and its analogues, especially in recreational settings. On the other hand, ketamine as medicine is considered safe and it is listed as an essential medicine by the World Health Organization. Although clinicians must remain vigilant, this should not deter appropriate prescription.

Long-term ketamine administration induces bladder damage and upregulates autophagy-associated proteins in bladder smooth muscle tissue

Long-term ketamine abuse can cause significant lower urinary tract symptoms in humans, termed ketamine-associated cystitis (KC). Here, we established a model of long-term (6 months) ketamine administration in wild-type (C57BL/6) mice. We elucidated the pathological effects of ketamine in the bladder and investigated changes in autophagy-associated protein expression (i.e., LC3, Beclin-1, and P62) and inflammatory cytokines (i.e., IL-6 and IL-1β) in the bladder smooth muscle tissue. Long-term ketamine administration reduced the number of layers in the bladder mucosal epithelial cells (4-5 layers in the saline group vs. 2-3 layers in the ketamine groups), but increased the number of mast cells and collagen fibers. LC3-II/LC3-I, Beclin-1, IL-6, and IL-1β protein expression in the bladder smooth muscle tissues of ketamine-treated mice was significantly increased. The mRNA and protein levels of P62 in the Ket-60 mg/kg group were also significantly increased, but not the Ket-30 mg/kg group. Our results reveal that long-term ketamine administration can cause cystitis-like pathological changes in mice, and the disordered autophagy in the bladder tissue may be involved in the persistent bladder damage following long-term administration of ketamine at 60 mg/kg.

Prevalence and Correlates of Providing and Receiving Assistance With the Transition to Injection Drug Use

Preventing the transition to injection drug use is an important public health goal, as people who inject drugs (PWID) are at high risk for overdose and acquisition of infectious disease. Initiation into drug injection is primarily a social process, often involving PWID assistance. A better understanding of the epidemiology of this phenomenon would inform interventions to prevent injection initiation and to enhance safety when assistance is provided. We conducted a systematic review of the literature to 1) characterize the prevalence of receiving (among injection-naive persons) and providing (among PWID) help or guidance with the first drug injection and 2) identify correlates associated with these behaviors. Correlates were organized as substance use behaviors, health outcomes (e.g., human immunodeficiency virus infection), or factors describing an individual's social, economic, policy, or physical environment, defined by means of Rhodes' risk environments framework. After screening of 1,164 abstracts, 57 studies were included. The prevalence of receiving assistance with injection initiation (help or guidance at the first injection) ranged 74% to 100% (n = 13 estimates). The prevalence of ever providing assistance with injection initiation varied widely (range, 13%-69%; n = 13 estimates). Injecting norms, sex/gender, and other correlates classified within Rhodes' social risk environment were commonly associated with providing and receiving assistance. Nearly all PWID receive guidance about injecting for the first time, whereas fewer PWID report providing assistance. Substantial clinical and statistical heterogeneity between studies precluded meta-analysis, and thus local-level estimates may be necessary to guide the implementation of future psychosocial and sociostructural interventions. Further, estimates of providing assistance may be downwardly biased because of social desirability factors.

Long-term ketamine administration causes Tau protein phosphorylation and Tau protein-dependent AMPA receptor reduction in the hippocampus of mice

As a recreational drug of abuse and an injectable anesthetic, ketamine has been shown to cause cognitive dysfunction and induce psychotic states. Although the specific mechanism is still unclear, it may be linked to synaptic receptors, including the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor. Recent evidence suggests that Tau protein phosphorylation and targeted delivery to the postsynaptic area is involved in maintaining neuronal plasticity, indicating that the neurotoxicity induced by ketamine may be related to the transfer of Tau protein after phosphorylation. In this study, we established a model of long-term (6 months) ketamine administration in wild-type (C57BL/6) and Tau knockout mice to investigate the effects of different doses of ketamine administration on Tau protein expression and phosphorylation in the mouse hippocampus. We also investigated changes in AMPA receptor expression in the synaptic membrane of wild-type and Tau knockout mice. Our results showed that long-term ketamine administration led to excessive Tau protein phosphorylation at Ser202/Thr205 and Ser396, but not at Ser199, Ser262 and Ser404. Most importantly, long-term ketamine administration decreased AMPA receptor levels in the hippocampal cell membrane in a Tau protein-dependent manner. Our results reveal the role of Tau protein phosphorylation in the mechanism of ketamine neurotoxicity, suggesting that the changes of membrane AMPA receptor and synaptic function induced by ketamine are mediated by abnormal phosphorylation of Tau protein at specific sites.

The experience of initiating injection drug use and its social context: a qualitative systematic review and thematic synthesis

BACKGROUND AND AIM

Understanding the experience of initiating injection drug use and its social contexts is crucial to inform efforts to prevent transitions into this mode of drug consumption and support harm reduction. We reviewed and synthesized existing qualitative scientific literature systematically to identify the socio-structural contexts for, and experiences of, the initiation of injection drug use.

METHODS

We searched six databases (Medline, Embase, PsychINFO, CINAHL, IBSS and SSCI) systematically, along with a manual search, including key journals and subject experts. Peer-reviewed studies were included if they qualitatively explored experiences of or socio-structural contexts for injection drug use initiation. A thematic synthesis approach was used to identify descriptive and analytical themes throughout studies.

RESULTS

From 1731 initial results, 41 studies reporting data from 1996 participants were included. We developed eight descriptive themes and two analytical (higher-order) themes. The first analytical theme focused on injecting initiation resulting from a social process enabled and constrained by socio-structural factors: social networks and individual interactions, socialization into drug-using identities and choices enabled and constrained by social context all combine to produce processes of injection initiation. The second analytical theme addressed pathways that explore varying meanings attached to injection initiation and how they link to social context: seeking pleasure, responses to increasing tolerance to drugs, securing belonging and identity and coping with pain and trauma.

CONCLUSIONS

Qualitative research shows that injection drug use initiation has varying and distinct meanings for individuals involved and is a dynamic process shaped by social and structural factors. Interventions should therefore respond to the socio-structural influences on injecting drug use initiation by seeking to modify the contexts for initiation, rather than solely prioritizing the reduction of individual harms through behavior change.

An Update on Nonopioids: Intravenous or Oral Analgesics for Perioperative Pain Management

Despite an appreciation for many unwanted physiologic effects from inadequate postoperative pain relief, moderate to severe postoperative pain remains commonplace. Although treatment options have evolved in recent years, the use of nonopioid analgesics agents can reduce acute pain-associated morbidity and mortality. This review focuses on the importance of effective postoperative nonopioid analgesic agents, such as acetaminophen, nonsteroidal anti-inflammatory agents, gabapentinoid agents, NMDA antagonists, alpha 2 agonists, and steroids, in opioid sparing and enhancing recovery. A careful literature review focusing on these treatment options, potential benefits, and side effects associated with these strategies is emphasized in this review.

Effects of Ketamine on Levels of Inflammatory Cytokines IL-6, IL-1β, and TNF-α in the Hippocampus of Mice Following Acute or Chronic Administration

Ketamine is an injectable anesthetic and recreational drug of abuse commonly used worldwide. Many experimental studies have shown that ketamine can impair cognitive function and induce psychotic states. Neuroinflammation has been suggested to play an important role in neurodegeneration. Meanwhile, ketamine has been shown to modulate the levels of inflammatory cytokines. We hypothesized that the effects of ketamine on the central nervous system are associated with inflammatory cytokines. Therefore, we set out to establish acute and chronic ketamine administration models in C57BL/6 mice, to evaluate spatial recognition memory and emotional response, to analyze the changes in the levels of the inflammatory cytokines interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in the mouse hippocampus, employing behavioral tests, Western blot, quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and immunohistochemistry. Our results showed that ketamine at the dose of 60 mg/kg induced spatial recognition memory deficit and reduced anxiety-like behaviors in mice after chronic administration. Moreover, we found that ketamine increased the hippocampal levels of IL-6 and IL-1β after single, multiple and long-term administration in a dose-dependent manner. However, the expression level of TNF-α differed in the mouse hippocampus under different conditions. Single administration of ketamine increased the level of TNF-α, whereas multiple and long-term administration decreased it significantly. We considered that TNF-α expression could be controlled by a bi-directional regulatory pathway, which was associated with the dose and duration of ketamine administration. Our results suggest that the alterations in the levels of inflammatory cytokines IL-6, IL-1β, and TNF-α may be involved in the neurotoxicity of ketamine.

Prevalence and Patterns of Prescription Drug Misuse among Young Ketamine Injectors

In recent years, epidemiological monitoring data has indicated sharp increases in prescription drug misuse. Despite these increases, little is known about the context or patterns associated with prescription drug misuse, particularly among youth or young injection drug users (IDUs). A three-city study of 213 young IDUs found prescription drug misuse to be pervasive, specifically the use of opioids and benzodiazepines. Particular practices not commonly associated with prescription drugs were reported, such as sniffing, smoking, and injection. Associated health risks included initiation into injection drug use, polydrug use, drug overdose, and drug dependency. A greater awareness of the potential health risks associated with prescription drug misuse should be incorporated into services that target IDUs, including street outreach, syringe exchanges, and drug treatment.

The fibrosis of ketamine, a noncompetitive N-methyl-d-aspartic acid receptor antagonist dose-dependent change in a ketamine-induced cystitis rat model

Ketamine abusers have greatly increased in number worldwide during recent years. The consumption of ketamine has increased, as have the number of published accounts of devastating urological sequelae. However, the mechanism of ketamine-associated urinary tract dysfunction remains unclear. This study was to evaluate the ketamine dose-dependency of ketamine-induced cystitis (KC) in a rat model. A total of 42 Sprague-Dawley rats (female, 10-week-old) were used. Each of the 7 KC rat models were induced by 1, 5, 10, 25 and 50 mg/kg ketamine intravenous injection for two weeks. For the sham group (n = 7), a phosphate-buffered saline (PBS) vehicle was used rather than ketamine hydrochloride. The cystometric parameters, histological examinations, staining for Masson's trichome, cytokeratin, toluidine blue and quantitative PCR were measured at two weeks following the intervention. The voiding interval gradually decreased depending upon the ketamine dose of 1, 5, 10, 25, or 50 mg/kg, respectively, and was decreased compared with Sham. Bladder capacity was decreased as ketamine dose increased. In particular, the increase of fibrosis and submucosal apoptosis were found according to the increase of the ketamine dose. The bladder apoptosis in the KC rat model makes the fibrotic bladder change, and led us to hypothesize that fibrosis could contribute to the lower urinary-tract symptoms. We suggest that according to the pathophysiology evidence, fibrosis induced by apoptosis plays a key role in KC.

Factors associated with being asked to initiate someone into injection drug use

AIMS

Injection drug use initiation typically involves an established person who injects drugs (PWID) helping the injection-naïve person to inject. Prior to initiation, PWID may be involved in behaviors that elevate injection initiation risk for non-injectors such as describing how to inject and injecting in front of injection-naïve people. In this analysis, we examine whether PWID who engage in either of these behaviors are more likely to be asked to initiate someone into drug injection.

METHODS

Interviews with PWID (N = 602) were conducted in California between 2011 and 2013. Multivariate analysis was conducted to determine factors associated with being asked to initiate someone.

RESULTS

The sample was diverse in terms of age, race/ethnicity, and drug use patterns. Seventy-one percent of the sample had ever been asked to initiate someone. Being asked to initiate someone was associated with having injected in front of non-injectors (Adjusted Odds Ratio [AOR] = 1.80, 95% Confidence Interval [CI] = 1.12, 2.91), having described injection to non-injectors (AOR = 3.63; 95% CI = 2.07, 6.36), and doing both (AOR = 9.56; 95% CI = 4.43, 20.65) as compared to doing neither behavior (referent). Being female (AOR = 1.73; 95% CI = 1.10, 2.73) and non-injection prescription drug misuse in the last 30 days (AOR = 1.69; 95% CI = 1.12, 2.53) were also associated with having been asked to initiate someone.

CONCLUSION

Reducing initiation into injection drug use is an important public health goal. Intervention development to prevent injection initiation should include established PWID and focus on reducing behaviors associated with requests to initiate injection and reinforcing refusal skills and intentions among established PWID.

Factors associated with initiating someone into illicit drug injection

AIMS

Most people who inject drugs (PWID) were first initiated into injection by a current PWID. Few studies have examined PWID who assist others into drug injection. Our goal is to describe the prevalence of and risk factors for initiating someone into injection in the last 12 months.

METHODS

We recruited a cross-sectional sample of PWID (N=605) in California from 2011 to 2013. We examined bivariate and multivariate risk factors for initiating someone into injection with a focus on behaviors that might encourage injection initiation such as injecting in front of non-PWID, describing how to inject to non-PWID, and willingness to initiate someone into drug injection.

RESULTS

Having initiated someone into injection was reported by 34% of PWID overall and 7% in the last 12 months. Forty-four PWID had assisted 431 people into injection in the past year. Factors independently associated with initiating someone into injection in the last 12 months were self-reported likelihood of initiating someone in the future (Adjusted Odds Ratio [AOR]=7.09; 95% Confidence Interval [CI]=3.40, 14.79), having injected another PWID in past month (AOR=4.05; 95% confidence interval [CI]=1.94, 8.47), having described how to inject to non-injectors (2.61; 95% CI=1.19, 5.71), and non-injection powder cocaine use in past month (AOR=4.97; 95% CI=2.08, 11.84) while controlling for study site.

CONCLUSION

Active PWID are important in facilitating the process of drug injection uptake. Interventions to reduce initiation should include efforts to change behaviors and intentions among PWID that are associated with injection uptake among others.

Perceived Drug Use Functions and Risk Reduction Practices Among High-Risk Nonmedical Users of Prescription Drugs

Nonmedical use of prescription drugs has become the fastest growing drug problem in the United States, particularly among young adults. This study examines the reasons young polydrug users misuse prescription drugs, and explores how young users employ risk reduction strategies to minimize adverse consequences. The sample was recruited during 2008 and 2009 in Los Angeles and New York, and comprised 45 nonmedical users of prescription drugs, aged 16 to 25. Data from a semistructured interview were analyzed quantitatively and qualitatively. Participants reported nonmedical use of prescription drugs to change mood, to facilitate activity, and to monitor the intake of other substances. Commonly employed risk reduction strategies included calculating pill timing, dosage, and access, and monitoring frequency of use, particularly when combining different substances. Most study participants often planned drug use to occur within socially acceptable parameters, such that prescription drug misuse was a normalized feature of their everyday lives.

Control over drug acquisition, preparation and injection: Implications for HIV and HCV risk among young female injection drug users

Young female injection drug users (IDUs) are at risk for HIV/HCV, and initiating the use of a new drug may confer additional and unexpected risks. While gender differences in the social context of injection drug use have been identified, it is unknown whether those differences persist during the initiation of a new drug. This mixed-methods study examined the accounts of 30 young female IDUs in Los Angeles, CA, USA from 2004 to 2006, who described the social context of initiating injection drug use and initiating ketamine injection. The analysis aimed to understand how the social context of young women's injection events contributes to HIV/HCV risk. Women's initiation into ketamine injection occurred approximately 2 years after their first injection of any drug. Over that time, women experienced changes in some aspects of the social context of drug injection, including the size and composition of the using group. A significant proportion of women described injection events characterized by a lack of control over the acquisition, preparation, and injection of drugs, as well as reliance on friends and sexual partners. Findings suggest that lack of control over drug acquisition, preparation, and injection may elevate women's risk; these phenomena should be considered as a behavioral risk factor when designing interventions.

Predictors of Transience Among Homeless Emerging Adults

This study identified predictors of transience among homeless emerging adults in three cities. A total of 601 homeless emerging adults from Los Angeles, Austin, and Denver were recruited using purposive sampling. Ordinary least squares regression results revealed that significant predictors of greater transience include White ethnicity, high school degree or equivalent, homeless residence in the 6 months prior to the study, longer period of homelessness, history of arrest and juvenile detention, earning income through informal sources, history of physical abuse, alcohol/drug addiction, and resilience characteristics. Quantitative findings were expanded upon with data from in-depth interviews with 145 of these homeless emerging adults regarding their reasons and motivations for transience. Identifying predictors of transience will facilitate customizing interventions that, when needed, aim to stabilize homeless emerging adults, prevent their mobility, and/or offer mobile services to them on the road.

Risk factor profiles among intravenous drug using young adults: a latent class analysis (LCA) approach

Using data from a cross-sectional study that examined health risk behaviors among urban intravenous drug-using (IDU) adolescents and young adults, this study investigated risk profiles among a high-risk sample (n=274). Risk profiles were empirically derived through latent class analysis based on indicators of engagement in health-risking behaviors, experience of abuse and violence as well as individual and family risk factors. The best fitting model was a 3-class model. Class 1 (n=95) captured participants with the lowest risk across all indicators. Compared to Class 1, Class 2 (n=128) and Class 3 (n=51) had elevated rates of engagement in health-risking behaviors as well as individual and family risk factors; however, Class 3 had the highest rate of engagement in sexual risk behavior, and backgrounds of substantial abuse and violence as well as familial psychopathology. Class 2 was the group most socioeconomically disadvantaged, with the highest percentage of participants coming from poor backgrounds, spending the longest time homeless and working the fewest months. Identifying subgroups of IDU has the potential to guide the development of more targeted and effective strategies for prevention and treatment of this high-risk population.

Patterns of prescription drug misuse among young injection drug users

Misuse of prescription drugs and injection drug use has increased among young adults in the USA. Despite these upward trends, few studies have examined prescription drug misuse among young injection drug users (IDUs). A qualitative study was undertaken to describe current patterns of prescription drug misuse among young IDUs. Young IDUs aged 16-25 years who had misused a prescription drug, e.g., opioids, tranquilizers, or stimulants, at least three times in the past 3 months were recruited in 2008 and 2009 in Los Angeles (n = 25) and New York (n = 25). Informed by an ethno-epidemiological approach, descriptive data from a semi-structured interview guide were analyzed both quantitatively and qualitatively. Most IDUs sampled were both homeless and transient. Heroin, prescription opioids, and prescription tranquilizers were frequently misused in the past 30 days. Qualitative results indicated that young IDUs used prescription opioids and tranquilizers: as substitutes for heroin when it was unavailable; to boost a heroin high; to self-medicate for health conditions, including untreated pain and heroin withdrawal; to curb heroin use; and to reduce risks associated with injecting heroin. Polydrug use involving heroin and prescription drugs resulted in an overdose in multiple cases. Findings point to contrasting availability of heroin in North American cities while indicating broad availability of prescription opioids among street-based drug users. The results highlight a variety of unmet service needs among this sample of young IDUs, such as overdose prevention, drug treatment programs, primary care clinics, and mental health services.

Denial of prescription opioids among young adults with histories of opioid misuse

OBJECTIVES

An exploratory study was undertaken to examine how being denied prescription opioids to treat pain impacted the drug-using careers of young adults with a history of misuse of prescription drugs.

DESIGN

Ethno-epidemiological methodology utilizing a cross-sectional design, semi-structured interviews, and qualitative/quantitative data analysis. Settings.  Non-clinical participants were recruited from natural settings, such as streets, parks, beaches, and college campuses, in New York City and Los Angeles during 2008 and 2009.

PARTICIPANTS

One hundred fifty participants aged 16 to 25 who had misused a prescription opioid, tranquilizer, or stimulant in the past 90 days. Outcome Measures.  Analyses focused on denial of opioids and associated consequences, including self-medication with prescription opioids and heroin.

RESULTS

Thirty-four participants (22.7%) described being denied prescription opioids for the treatment of a painful condition. Current opioid misuse and current pain problems were higher in this group compared to those who had never been denied prescription opioids. Reasons for denial included being identified as a drug user by a physician, lack of health insurance, and having medication withheld by a parent or authority figure. Approximately half reported self-medicating pain with either illegally obtained prescription opioids or heroin. Self-medication often coincided with initiation of new risk behaviors and more intensive drug use.

CONCLUSION

Being denied prescription opioids was an important moment in the drug using careers of many study participants. Results suggest that effective pain management techniques are needed to prevent high-risk young adults with pain problems from engaging in escalated opioid misuse and risk behaviors.

"A costly turn on": patterns of use and perceived consequences of mephedrone based head shop products amongst Irish injectors

BACKGROUND

Mephedrone injecting has recently been reported in Romania, Slovenia, Guernsey and Ireland. The research reported here aimed to describe the experiences of a group of Irish injecting drug users, who were injecting mephedrone based headshop products prior to the introduction of legislative controls in Ireland, with particular focus on pre- and post-legislative use, effects of injecting mephedrone, settings and contexts for injecting, polydrug use and serial drug injecting, risk perceptions and harm reduction practises.

METHODS

Following a predevelopment phase with a Privileged Access Interviewer, in-depth interviews using a phenomenological approach were conducted with eleven attendees of a low threshold harm reduction service.

RESULTS

The findings describe the abuse potential of these mephedrone based headshop products when used by intravenous injection. Although participants were aware of risks and safe injecting practises, compulsive re injecting with excessive binge use over long periods of time was common. Nasal to injection route transitions, intense paranoia, violent behaviour and aggression, emergence of Parkinson type symptomatologies (in the form of spasms and 'wobbling'), and permanent numbness in lower extremities were reported. Multi and serial drug injecting with heroin was used in efforts to manage the intense rush and avoid unpleasant comedown. Participants reported limb abscesses, vein clotting, damage and recession resulting from product toxicity, crystallisation of the products when diluted and flushing practises. Seven participants were homeless, with groin and street injecting common. Following legislative changes use of mephedrone products declined due to closure of headshops, increased street prices, concerns around contamination and the emergence of new street stimulant drugs.

CONCLUSION

Continued monitoring of drug displacement patterns in post legislative time frames is advised, alongside longitudinal ethnographic research to track the diffusion of mephedrone and other cathinone derivatives within injecting networks. Further investigation of the adverse health consequences of these drugs on injection is warranted.

Initiation into prescription opioid misuse amongst young injection drug users

BACKGROUND

Prescription opioids are the most frequently misused class of prescription drugs amongst young adults. Initiation into prescription opioid misuse is an important public health concern since opioids are increasingly associated with drug dependence and fatal overdose. Descriptive data about initiation into prescription opioid misuse amongst young injection drug users (IDUs) are scarce.

METHODS

An exploratory qualitative study was undertaken to describe patterns of initiation into prescription opioid misuse amongst IDUs aged 16-25 years. Those young IDUs who had misused a prescription drug at least three times in the past three months were recruited during 2008 and 2009 in Los Angeles (n=25) and New York (n=25). Informed by an ethno-epidemiological approach, descriptive data from a semi-structured interview guide were analysed both quantitatively and qualitatively.

RESULTS

Initiation into prescription opioid misuse was facilitated by easy access to opioids via participant's own prescription, family, or friends, and occurred earlier than misuse of other illicit drugs, such as heroin. Nearly all transitioned into sniffing opioids, most injected opioids, and many initiated injection drug use with an opioid. Motives for transitions to sniffing and injecting opioids included obtaining a more potent high and/or substituting for heroin; access to multiple sources of opioids was common amongst those who progressed to sniffing and injecting opioids.

CONCLUSION

Prescription opioid misuse was a key feature of trajectories into injection drug use and/or heroin use amongst this sample of young IDUs. A new pattern of drug use may be emerging whereby IDUs initiate prescription opioid misuse before using heroin.

Permanent deficits in brain functions caused by long-term ketamine treatment in mice

Ketamine, an injectable anesthetic, is also a popular recreational drug used by young adults worldwide. Ketamine is a non-competitive antagonist of N-methyl-d-aspartate receptor, which plays important roles in synaptic plasticity and neuronal learning. Most previous studies have examined the immediate and short-term effects of ketamine, which include learning and cognitive deficits plus impairment of working memory, whereas little is known about the long-term effects of repeated ketamine injections of common or usual recreational doses. Therefore, we aimed to evaluate the deficits in brain functions with behavioral tests, including wire hang, hot plate and water maze tests, plus examine prefrontal cortex apoptotic markers, including Bax, Bcl-2 and caspase-3, in mice treated with 6 months of daily ketamine administration. In our study, following 6 months of ketamine injection, mice showed significant deterioration in neuromuscular strength and nociception 4 hours post-dose, but learning and working memory were not affected nor was there significant apoptosis in the prefrontal cortex. Our research revealed the important clinical finding that long-term ketamine abuse with usual recreational doses can detrimentally affect neuromuscular strength and nociception as part of measurable, stable and persistent deficits in brain function.

Longitudinal trajectories of ketamine use among young injection drug users

BACKGROUND

Ketamine is a dissociative anaesthetic that became increasingly popular in the club and rave scene in the 1980s and 1990s. Reports surfaced in the late 1990s indicating that ketamine was being injected in several U.S. cities by young injection drug users (IDUs). Since all studies on ketamine injection were cross-sectional, a longitudinal study was undertaken in 2005 to determine: characteristics of young IDUs who continue to inject ketamine; frequency of ketamine injection over an extended time period; risks associated with ongoing ketamine injection; and environmental factors that impact patterns of ketamine use.

METHODS

Young IDUs aged 16-29 with a history of injecting ketamine (n=101) were recruited from public locations in Los Angeles and followed during a 2-year longitudinal study. A semi-structured instrument captured quantitative and qualitative data on patterns of ketamine injection and other drug use. A statistical model sorted IDUs who completed three or more interviews (n=66) into three groups based upon patterns of ketamine injection at baseline and follow-up. Qualitative analysis focused on detailed case studies within each group.

RESULTS

IDUs recruited at baseline were typically in their early 20s, male, heterosexual, white, and homeless. Longitudinal injection trajectories included: "Moderates," who injected ketamine several times per year (n=5); "Occasionals," who injected ketamine approximately once per year (n=21); and "Abstainers," who did not inject any ketamine during follow-up (n=40). Findings suggest that ketamine is infrequently injected compared to other drugs such as heroin, cocaine, and methamphetamine. Most IDUs who begin injecting ketamine will stop or curb use due to: negative or ambivalent experiences associated with ketamine; an inability to find the drug due to declining supply; or maturing out of injecting drugs more generally.

CONCLUSION

Reducing ketamine injection among young IDUs may best be accomplished by targeting particular groups of IDUs identified in this study, such as homeless youth and homeless travellers.

Recruiting and retaining mobile young injection drug users in a longitudinal study

Longitudinal studies that research homeless persons or transient drug users face particular challenges in retaining subjects. Between 2005 and 2006, 101 mobile young injection drug users were recruited in Los Angeles into a 2-year longitudinal study. Several features of ethnographic methodology, including fieldwork and qualitative interviews, and modifications to the original design, such as toll-free calls routed directly to ethnographer cell phones and wiring incentive payments, resulted in retention of 78% of subjects for the first follow-up interview. Longitudinal studies that are flexible and based upon qualitative methodologies are more likely to retain mobile subjects while also uncovering emergent research findings.

The toxic effect of ketamine on SH-SY5Y neuroblastoma cell line and human neuron

Ketamine used as an injectable anesthetic in human and animal medicine is also a recreational drug used primarily by young adults often at all night dance parties in nightclubs. The percentage of ketamine users has grown very fast in the last 5 years worldwide. However, this leads to the serious question of the long-term adverse effects of ketamine on our nervous system, particularly the brain, because ketamine as an NMDA antagonist could cause neurons to commit apoptosis. Our study therefore aimed to find out the chronic effect of ketamine on neuron using prolonged incubation (48 h) of neuronal cells with ketamine in culture. Our results showed that differentiated neuronal cells were prone to the toxicity of ketamine but probably less susceptible than undifferentiated neuronal cells and fibroblasts. This suggested that the ketamine abuse would be harmful to many other organs as well as the brain. Our results also confirmed that the toxicity of ketamine is related to apoptosis via the Bax/Bcl-2 ratio pathway and caspase-3 in the differentiated neuronal cells. Therefore, long-term ketamine treated cell or animal models should be sought to study this multiorgan effects of ketamine.

Hyperphosphorylated tau in the brains of mice and monkeys with long-term administration of ketamine

Ketamine, a non-competitive antagonist at the glutamatergic N-methyl-d-aspartate (NMDA) receptor, might impair memory function of the brain. Loss of memory is also a characteristic of aging and Alzheimer's disease. Hyperphosphorylation of tau is an early event in the aging process and Alzheimer's disease. Therefore, we aimed to find out whether long-term ketmaine administration is related to hyperphosphorylation of tau or not in the brains of mice and monkeys. Results showed that after 6 months' administration of ketamine, in the prefrontal and entorhinal cortical sections of mouse and monkey brains, there were significant increases of positive sites for the hyperphosphorylated tau protein as compared to the control animals receiving no ketamine administration. Furthermore, about 15% of hyperphosphorylated tau positive cells were also positively labeled by terminal dUTP nick end labeling (TUNEL) indicating there might be a relationship between hyperphosphorylation of tau and apoptosis. Therefore, the long-term ketamine toxicity might involve neurodegenerative process similar to that of aging and/or Alzheimer's disease.

THE FIRST INJECTION EVENT: DIFFERENCES AMONG HEROIN, METHAMPHETAMINE, COCAINE, AND KETAMINE INITIATES

This article describes how the drug type injected at the first injection event is related to characteristics of the initiate, risk behaviors at initiation, and future drug-using trajectories. A diverse sample (n=222) of young injection drug users (IDUs) were recruited from public settings in New York, New Orleans, and Los Angeles during 2004 and 2005. The sample was between 16 and 29 years old, and had injected ketamine at least once in the preceding two years. Interview data was analyzed both quantitatively and qualitatively. Young IDUs initiated with four primary drug types: heroin (48.6%), methamphetamine (20.3%), ketamine (17.1%), and cocaine (14%). Several variables evidenced statistically significant relationships with drug type: age at injection initiation, level of education, region of initiation, setting, mode of administration, patterns of self-injection, number of drugs ever injected, current housing status, and their hepatitis C virus (HCV) status. Qualitative analyses revealed that rationale for injection initiation and subjective experiences at first injection differed by drug type.

Multiple drug use and polydrug use amongst homeless traveling youth

Diverse forms of drug use are an emerging theme within research on young people and substance use. This manuscript, based on a three city study of health risks amongst young injection drug users, explores multiple drug use and polydrug use amongst a subset of homeless youth referred to as "travelers." In particular, we outline characteristics of homeless traveler youths and the various ways in which they practiced multiple drug use and polydrug use. From here, we discuss some theoretical and public health implications of multiple drug use and polydrug use amongst this particular population.

A TYPOLOGY OF DRUG-RELATED OFFENDING AMONG YOUNG HOMELESS INJECTION DRUG USERS

Research indicates a link between drug use and offending, particularly amongst high-risk individuals, such as homeless youth. The extent to which such youth interpret their offending as being related to their drug use, though, is understudied. This manuscript investigates the interpretations of drug-related offenses offered by 151 primarily white, male, homeless IDUs aged 16-29 years. Youth were asked specific questions about their drug-related offenses during in-depth interviews as part of a larger study investigating health risks surrounding drug injection between 2004 and 2006. The first section of the manuscript outlines offenses youth revealed committing either in pursuit of or after using a variety of substances. The second part of the manuscript examines the overall context (motivation, environment), and provides a seven-tiered typology of drug-related offending based on youth's interpretations, linking certain drugs to specific offenses within particular contexts. From here, some theoretical and practical implications of the findings are discussed.

Incidence and predictors of onset of injection drug use in a San Francisco cohort of homeless youth

Few studies document incidence of injection drug use among homeless youth. We followed a cohort of 70 street-recruited homeless youth in San Francisco, California who had never injected drugs for six months in 2004-5. We examined initiation of injection drug use and its predictors, informed by prior ethnographic findings. Data were analyzed using exact logistic regression. 11.4% of youth initiated injection drug use. Having no high school education, being over 21 years old, and being in disequilibrium predicted initiation. Limitations, implications and suggestions for future research are noted. Funding was provided by the National Institute for Child Health and Development.

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.

Apoptotic insults to human HepG2 cells induced by S-(+)-ketamine occurs through activation of a Bax-mitochondria-caspase protease pathway

BACKGROUND

Ketamine is widely used as an i.v. anaesthetic agent and as a drug of abuse. Hepatocytes contribute to the metabolism of endogenous and exogenous substances. This study evaluated the toxic effects of S-(+)-ketamine and possible mechanisms using human hepatoma HepG2 cells as the experimental model.

METHODS

HepG2 cells were exposed to S-(+)-ketamine. Cell viability and the release of lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GPT) were measured to determine the toxicity of S-(+)-ketamine to HepG2 cells. Cell morphology, DNA fragmentation, and apoptotic cells were analysed to evaluate the mechanism of S-(+)-ketamine-induced cell death. Amounts of Bax, an apoptotic protein, and cytochrome c in the cytoplasm or mitochondria were quantified by immunoblotting. Cellular adenosine triphosphate levels were analysed using a bioluminescence assay. Caspases-3, -9, and -6 were measured fluorometrically.

RESULTS

Exposure of HepG2 cells to S-(+)-ketamine increased the release of LDH and GPT, but decreased cell viability (all P<0.01). S-(+)-Ketamine time-dependently caused shrinkage of HepG2 cells. Exposure to S-(+)-ketamine led to significant DNA fragmentation and cell apoptosis (P=0.003 and 0.002). S-(+)-Ketamine increased translocation of Bax from the cytoplasm to mitochondria, but decreased the mitochondrial membrane potential and cellular adenosine triphosphate levels (all P<0.01). Sequentially, cytosolic cytochrome c levels and activities of caspases-9, -3, and -6 were augmented after S-(+)-ketamine administration (all P<0.001). Z-VEID-FMK, an inhibitor of caspase-6, alleviated the S-(+)-ketamine-induced augmentation of caspase-6 activity, DNA fragmentation, and cell apoptosis (all P<0.001).

CONCLUSIONS

This study shows that S-(+)-ketamine can induce apoptotic insults to human HepG2 cells via a Bax-mitochondria-caspase protease pathway. Thus, we suggest that S-(+)-ketamine at a clinically relevant or an abused concentration may induce liver dysfunction possibly due to its toxicity to hepatocytes.

Pregnancy and sexual health among homeless young injection drug users

Research on pregnancy and sexual health among homeless youth is limited. In this study, qualitative interviews were conducted with 41 homeless young injection drug users (IDUs) in Los Angeles with a history of pregnancy. The relationship between recent pregnancy outcomes, contraception practices, housing status, substance use, utilization of prenatal care, and histories of sexual victimization are described. A total of 81 lifetime pregnancies and 26 children were reported. Infrequent and ineffective use of contraception was common. While pregnancy motivated some homeless youth to establish housing, miscarriages and terminations were more frequent among youth who reported being housed. Widespread access to prenatal and medical services was reported during pregnancy, but utilization varied. Many women continued to use substances throughout pregnancy. Several youth reported childhood sexual abuse and sexual victimization while homeless. Pregnancy presents a unique opportunity to encourage positive health behaviors in a high-risk population seldom seen in a clinical setting.

Ecstasy and other club drugs: a review of recent epidemiologic studies

PURPOSE OF REVIEW

This review highlights the epidemiologic research on club drug use in the past year, with a focus on clinical epidemiology, social epidemiology, new methodological approaches, and alternative explanations for drug use behaviors.

RECENT FINDINGS

Although 3,4-methylenedioxy-N-methylamphetamine (MDMA) or ecstasy is currently classified as a type of hallucinogen and its withdrawal is not recognized in the Diagnostic and Statistical Manual of Mental Disorders, there is evidence for the association of withdrawal symptoms with MDMA abstinence. Findings from latent class analysis indicate that MDMA users have a significantly higher risk of dependence than lysergic acid diethylamide users. Research on sociodemographic factors associated with club drug use continues to be a main focus worldwide. New epidemiologic research methods have been developed to enable researchers to monitor real-time drug use behaviors and to conduct surveys on sensitive issues in public places. In addition to traditional behavioral models, researchers began to examine the club drug phenomenon in the context of economic environment.

SUMMARY

Recent findings on MDMA use further question the current drug classification in the diagnostic systems. Despite the continuous growth in the club drug research literature, there is no study on the influence of genetic factors on club drug use. More research in this area is needed.

Racial and ethnic changes in heroin injection in the United States: implications for the HIV/AIDS epidemic

BACKGROUND

Racial/ethnic differences in drug injection prevalence contribute to disparities in HIV infection rates in the US between Whites, Blacks and Hispanics. We examine trends in the demographic characteristics of heroin injection drug users (IDUs) that may impact future HIV rates.

METHODS

Descriptive analyses were conducted of (1) the national Treatment Episode Data Set for 1992-2004 and of the 2002-2004 baseline data from (2) CIDUS-III, a 5-city study that recruited 3285 young IDUs, and (3) NIHU-HIT, a Chicago study of 647 young noninjecting heroin users.

RESULTS

Between 1992 and 2004, heroin was the injected drug most often reported at admission to drug treatment. During this period, the proportion of admissions reporting injection declined 44% among Blacks but only 14% for Whites. The peak age for heroin IDUs in treatment increased 10 years for Blacks while declining over 10 years for Whites. CIDUS-III enrolled about 8 times more White (64%) than Black (8%) young IDUs despite recruiting two-thirds of the sample in cities where Blacks constituted 27-64% of the population. Blacks comprised 53% of noninjecting heroin users in the Chicago NIHU-HIT, but only 2% of Chicago's CIDUS-III sample of heroin IDUs. Among current noninjecting heroin users, Whites were more likely than Blacks to have ever injected (X(d.f.=1)(2)=17.1, p<0.001). Qualitative data supported greater resistance to injection among young Blacks than Whites.

CONCLUSIONS

Among heroin users, young Blacks are resisting injection while young Whites exhibit the opposite tendency. New research should investigate reasons for this trend and its impact on the HIV epidemic and future service needs.

"Research chemicals": tryptamine and phenethylamine use among high-risk youth

Tryptamines and phenethylamines are two broad categories of psychoactive substances with a long history of licit and illicit use. Profiles of users of recently emerging tryptamines and phenethylamines are nonexistent, however, since surveillance studies do not query the use of these substances. This manuscript describes the types, modes of administration, onset of use, and context of use of a variety of lesser known tryptamines and phenethylamines among a sample of high-risk youth. Findings are based upon in-depth interviews with 42 youth recruited in public settings in Los Angles during 2005 and 2006 as part of larger study examining health risks associated with injecting ketamine. Youth reported that their use of tryptamines and phenethylamines was infrequent, spontaneous, and predominately occurred at music venues, such as festivals, concerts, or raves. Several purchased a variety of these "research chemicals" from the Internet and used them in private locations. While many described positive experiences, reports of short-term negative health outcomes included nausea, vomiting, diarrhea, disorientations, and frightening hallucinations. These findings, based upon pilot study data, move toward an epidemiology of tryptamine and phenethylamine use among high-risk youth.

Towards an Explanation of Subjective Ketamine Experiences among Young Injection Drug Users

Ketamine is a dissociative anesthetic with powerful sedative and hallucinogenic properties. Despite the wide variability in reported subjective experiences, no study has attempted to describe the particular factors that shape these experiences. This manuscript is based upon a sample of 213 young injection drug users recruited in New York, New Orleans, and Los Angeles with histories of ketamine use. Qualitative interviews focused on specific ketamine events, such as first injection of ketamine, most recent injection of ketamine, and most recent experience sniffing ketamine. Findings indicate that six factors impacted both positive and negative ketamine experiences: polydrug use, drug using history, mode of administration, quantity and quality of ketamine, user group, and setting. Most subjective experiences during any given ketamine event were shaped by a combination of these factors. Additionally, subjective ketamine experiences were particularly influenced by a lifestyle characterized by homelessness and traveling.

HIV Sexual Risk Behaviors among Ketamine and Non-Ketamine Using Criminal Offenders Prior to Prison Entry

This study is the first to examine ketamine use and its association with HIV sexual risk behaviors among a criminal offending population in the United States. Data were collected from 716 inmates as part of the Transitional Case Management (TCM) protocol within the Criminal Justice Drug Abuse Treatment Studies (CJ-DATS) cooperative agreement. Bivariate analyses were used to identify differences between ketamine users (n=44) and non-ketamine users (n=672). Three Poisson regression models were used to identify the significant correlates of high risk sexual behaviors in the 30 days prior to incarceration-- (1) number of times had unprotected sex while high, (2) number of times had unprotected vaginal sex, and (3) number of times had unprotected anal sex. Results indicate that ketamine was a significant correlate in all of the Poisson regression models. Findings add to the literature and indicate that ketamine use may be a marker for engaging in HIV risk behaviors among criminal offenders.

Ketamina, da anestesia ao uso abusivo

Objetivo. Realizar uma revisão bibliográfica sobre a ketamina, enfocando aspectos químicos e farmacocinéticos, seus mecanismos de ação, efeitos farmacológicos, usos terapêuticos, bem como aborda o uso da ketamina como droga de abuso. Ketamina. Método. Estudo de revisão bibliográfica através das bases de dados Pubmed, SciELO, Lilacs e Medline, na qual foram selecionados estudos clássicos e recentes relevantes para a discussão do tema abordado. Resultados. Após análise dos artigos selecionados, conclui-se que a ketamina apresenta perspectivas promissoras. Alguns estudos demonstraram propriedades analgésicas em relação à dor pós-operatória e outros revelaram uma ação antidepressiva rápida. Além disto, a ketamina também apresentou efeitos neuroprotetores em vários estudos animais. Embora a ketamina seja um campo promissor, essas ações precisam ser melhor investigadas. Atualmente, observou-se que o seu uso não se restringe apenas à prática clínica ou pesquisa, sendo frequentemente utilizada como droga de abuso pelos jovens em festas como um potente alucinógeno. Conclusão. Pesquisas sobre o uso recreacional da ketamina também são necessárias, especialmente no Brasil, assim como dados que mostrem a morbidade e mortalidade pelo uso desta substância como droga de abuso.