Cocaine abuse among heroin addicts in Spain

Dopamine Supersensitivity: A Novel Hypothesis of Opioid-Induced Neurobiological Mechanisms Underlying Opioid-Stimulant Co-use and Opioid Relapse

Emergent harms presented by the co-use of opioids and methamphetamine highlight the broader public health challenge of preventing and treating opioid and stimulant co-use. Development of effective therapeutics requires an understanding of the physiological mechanisms that may be driving co-use patterns, specifically the underlying neurobiology of co-use and how they may facilitate (or be leveraged to prevent) continued use patterns. This narrative review summarizes largely preclinical data that demonstrate clinically-meaningful relationships between the dopamine and opioid systems with direct implications for opioid and stimulant co-use. Synthesized conclusions of this body of research include evidence that changes in the dopamine system occur only once physical dependence to opioids develops, that the chronicity of opioid exposure is associated with the severity of changes, and that withdrawal leaves the organism in a state of substantive dopamine deficit that persists long after the somatic or observed signs of opioid withdrawal appear to have resolved. Evidence also suggests that dopamine supersensitivity develops soon after opioid abstinence and results in increased response to dopamine agonists that increases in magnitude as the abstinence period continues and is evident several weeks into protracted withdrawal. Mechanistically, this supersensitivity appears to be mediated by changes in the sensitivity, not quantity, of dopamine D2 receptors. Here we propose a neural circuit mechanism unique to withdrawal from opioid use with implications for increased stimulant sensitivity in previously stimulant-naïve or inexperienced populations. These hypothesized effects collectively delineate a mechanism by which stimulants would be uniquely reinforcing to persons with opioid physical dependence, would contribute to the acute opioid withdrawal syndrome, and could manifest subjectively as craving and/or motivation to use that could prompt opioid relapse during acute and protracted withdrawal. Preclinical research is needed to directly test these hypothesized mechanisms. Human laboratory and clinical trial research is needed to explore these clinical predictions and to advance the goal of developing treatments for opioid-stimulant co-use and/or opioid relapse prevention and withdrawal remediation.

Ethical and policy issues in using vaccines to treat and prevent cocaine and nicotine dependence

PURPOSE OF REVIEW

To describe the rationale of vaccines against cocaine and nicotine, to review progress in developing and trialing vaccines to treat dependence on these drugs and to discuss some of the ethical issues that may arise from their use in legally coerced addiction treatment or for prevention of addiction in adolescents.

RECENT FINDINGS

Several randomized controlled trials of cocaine and nicotine vaccines for relapse prevention have produced mixed results. The studies demonstrate that it is possible to raise antibodies to cocaine and nicotine in humans. In abstinent patients who show high levels of drug antibodies, the rewarding effects of these drugs are attenuated. Phase 2 trials have not found nicotine vaccines to be superior to placebo because only a third of those vaccinated develop sufficient levels of antibody to block the effects of nicotine.

SUMMARY

Vaccines are a novel approach to relapse prevention that need to more reliably induce immunity in a larger proportion of vaccinated patients if they are to protect against relapse after achieving abstinence. Vaccines are unlikely to prevent addiction in adolescents. Their use under legal coercion should only be considered after considerable experience with their use in voluntary patients.

Powerful behavioral interactions between methamphetamine and morphine

Use of drugs of abuse in combination is common among recreational users and addicts. The combination of a psychomotor stimulant with an opiate, known as a 'speedball,' reportedly produces greater effects than either drug alone and has been responsible for numerous deaths. Historically, the most popular speedball combination is that of cocaine and heroin. However, with the growing popularity of methamphetamine in recent years, there has been increased use of this drug in combination with other drugs of abuse, including opiates. Despite this, relatively little research has examined interactions between methamphetamine and opiates. In the current research, behavioral interactions between methamphetamine and the prototypical opiate, morphine, were examined across a variety of dose combinations in Sprague-Dawley rats. The combination of methamphetamine and morphine produced stimulation of behavior that was dramatically higher than either drug alone; however, the magnitude of the interaction was dependent on the dose of the drugs and the specific behaviors examined. The results demonstrate complex behavioral interactions between these drugs, but are consistent with the idea that this combination is used because it produces a greater effect than either drug alone.

Sustained release d-amphetamine reduces cocaine but not 'speedball'-seeking in buprenorphine-maintained volunteers: a test of dual-agonist pharmacotherapy for cocaine/heroin polydrug abusers

The aim of this study was to determine whether oral sustained release d-amphetamine (SR-AMP) reduces cocaine and opioid/cocaine combination ('speedball'-like) seeking in volunteers with current opioid dependence and cocaine dependence. Following outpatient buprenorphine (BUP) 8 mg/day stabilization without SR-AMP, eight participants completed a 3-week in-patient study with continued BUP 8 mg/day maintenance and double-blind ascending SR-AMP weekly doses of 0, 30, and 60 mg/day, respectively. After 3 days (Saturday-Monday) stabilization at each SR-AMP weekly dose (0, 15, or 30 mg administered at 0700 and 1225 each day), on Tuesday-Friday mornings (0900-1200 hours), participants sampled four drug combinations in randomized, counterbalanced order under double-blind, double-dummy (intranasal cocaine and intramuscular hydromorphone) conditions: cocaine (COC 100 mg+saline); hydromorphone (COC 4 mg+HYD 24 mg); 'speedball' (COC 100 mg+HYD 24 mg); and placebo (COC 4 mg+saline). Subjective and physiological effects of these drug combinations were measured. From 1230 to 1530 hours, participants could respond on a choice, 12-trial progressive ratio schedule to earn drug units (1/12th of total morning dose) or money units (US$2). SR-AMP significantly reduced COC, but not HYD or speedball, choices and breakpoints. SR-AMP also significantly reduced COC subjective (eg, abuse-related) effects and did not potentiate COC-induced cardiovascular responses. This study shows the ability of SR-AMP to attenuate COC self-administration, as well as its selectivity, in cocaine/heroin polydrug abusers. Further research is warranted to ascertain whether SR-AMP combined with BUP could be a useful dual-agonist pharmacotherapy.

Current trends in tramadol-related fatalities, Tehran, Iran 2005-2008

Tramadol is a widely prescribed drug. Abuse of tramadol as well as tramadol-related deaths have been increasing in Iran. The objective of the present study is to evaluate the trends of tramadol-related deaths that occurred between 2005 and 2008 in Tehran, Iran. Biological samples obtained during the autopsy were analyzed. Tramadol was detected in 294 cases by itself or together with other drugs. The majority of the cases were young male adults. Tramadol-related deaths in 2008 were 32.5 times more than in 2005. These results suggest that tramadol-related fatalities are growing in Iran especially among substance abusers.

Increased risk for hepatitis C associated with solvent use among Canadian Aboriginal injection drug users

Background

Solvent abuse is a particularly serious issue affecting Aboriginal people. Here we examine the association between solvent use and socio-demographic variables, drug-related risk factors, and pathogen prevalence in Aboriginal injection drug users (IDU) in Manitoba, Canada.

Methods

Data originated from a cross-sectional survey of IDU from December 2003 to September 2004. Associations between solvent use and variables of interest were assessed by multiple logistic regression.

Results

A total of 266 Aboriginal IDU were included in the analysis of which 44 self-reported recent solvent use. Hepatitis C infection was 81% in solvent-users, compared to 55% in those reporting no solvent use. In multivariable models, solvent-users were younger and more likely to be infected with hepatitis C (AOR: 3.5; 95%CI: 1.3,14.7), to have shared needles in the last six months (AOR: 2.6; 95%CI:1.0,6.8), and to have injected talwin & Ritalin (AOR: 10.0; 95%CI: 3.8,26.3).

Interpretation

High hepatitis C prevalence, even after controlling for risky injection practices, suggests that solvent users may form closed networks of higher risk even amongst an already high-risk IDU population. Understanding the social-epidemiological context of initiation and maintenance of solvent use is necessary to address the inherent inequalities encountered by this subpopulation of substance users, and may inform prevention strategies for other marginalized populations.

Behavioral economic analysis of opioid consumption in heroin-dependent individuals: effects of alternative reinforcer magnitude and post-session drug supply

This study investigated the extent to which hydromorphone (HYD) choice and behavioral economic demand were influenced by HYD unit price (UP), alternative money reinforcement magnitude and post-session HYD supply. Heroin-dependent research volunteers (n=13) stabilized on buprenorphine 8 mg/day first sampled two HYD doses (12 and 24 mg IM, labeled Drug A [session 1] and Drug B [session 2]). In each of the final six sessions, volunteers were given access to a 12-trial choice progressive ratio (PR) task and could earn a HYD unit dose (2 mg, fixed) or money ($2 or $4, varied across sessions), administered immediately after the work session. Before the PR task, volunteers were told which HYD supplemental dose (none, Drug A or B) would be available 3h after receiving the PR-contingent dose. PR-contingent HYD choice significantly decreased when $4 relative to $2 was concurrently available. Information about the post-session HYD supplement moderated this effect: when subjects were told a supplemental dose was available, HYD-seeking behavior decreased when the money alternative was smaller ($2), but this information did not further attenuate HYD choice, which was already low, when the money alternative was higher ($4). HYD demand elasticity was only increased by the $4 relative to $2 alternative without the HYD supplement. In summary, opioid-seeking behavior is influenced by the availability of concurrent non-drug and drug alternatives. These findings show that drug availability and non-drug alternatives interact to modulate drug-seeking behavior.

The association between cocaine use and short-term outcomes for the treatment of heroin dependence: findings from the Australian Treatment Outcome Study (ATOS)

The aim of this study was to determine the prevalence of cocaine use among individuals presenting for treatment for heroin dependence, describe the clinical profile of heroin users who also use cocaine and to establish the effects of cocaine use on short term outcomes for the treatment for heroin dependence. A longitudinal follow-up of 549 heroin users recruited in Sydney for the Australian Treatment Outcome Study was conducted at 3-month post-baseline interview. At baseline, current cocaine use was common (39%) and was associated with increased drug use, needle risk taking and criminality. The 3-month prevalence of cocaine use declined significantly to 19%. Thirty-five per cent of those who had used cocaine at baseline continued to use at 3 months, while 9% of the sample had commenced cocaine use. Those who entered residential rehabilitation at baseline were less likely than other treatment entrants and the non-treatment group to have used cocaine at follow-up. Treatment retention was not affected by baseline cocaine use status; however, baseline cocaine users (CU) displayed higher levels of heroin use, polydrug use and drug-related problems. A poorer outcome was associated with the commencement or continuation of cocaine use, while cessation of cocaine use resulted in significant improvements on these measures. Cocaine use was common among individuals seeking treatment for heroin dependence and was an important moderator of treatment outcome. It appears that cocaine use has a strong negative effect on treatment outcome over and above that caused by polydrug use generally.

Injecting drug users and the Human Immunodeficiency Virus: what do we know?

This article examines the results of 10 years of research on the relationship between injecting drug use and the Human Immunodeficiency Virus (HIV). The two main transmission modes of HIV among injecting drug users (IDU)-parenteral drug use and sexual behaviour-are examined in detail, as well as the efficacy of attempted interventions to reduce the spread of HIV among this population.

Meta-analysis of depression and substance use and impairment among cocaine users

BACKGROUND

The study evaluated, among cocaine users, the hypothesized positive association of depression and concurrent cocaine use and impairment, alcohol use and impairment, and general drug use and impairment. The hypothesis that gender would moderate these associations, with women showing a stronger correlation between depression and measures of substance use and impairment, was also tested. Also examined was the association of depression with future cocaine use and impairment and substance use treatment participation.

METHODS

Empirical reports on adult cocaine users published in English in peer-reviewed journals since 1986 that contained data on depression and substance use outcome(s) were obtained using a systematic search. Studies that placed restrictions on range of depression scores to select the sample, experiments that administered cocaine to subjects, and trials of antidepressant medications were excluded. The search yielded 60 studies for the analysis including 53 reports that collected data from clinical venues and seven that were community-based.

RESULTS

As hypothesized, the analyses showed that depression is associated with concurrent cocaine-, alcohol-, and general drug use and impairment. Effect sizes were small. Hypothesized moderating effects of gender were not supported. Depression was not associated, at a statistically significant level, with treatment participation or future cocaine use and impairment.

CONCLUSIONS

Depression is consistently but modestly associated with measures of cocaine-, alcohol-, and general drug use and impairment among cocaine users. Associations of depression with treatment participation and with future cocaine use and impairment are not immediately evident, although limitations of data warrant cautious interpretation.

Meta-analysis of depression and substance use and impairment among intravenous drug users (IDUs)

AIMS

To evaluate, among intravenous drug users (IDUs), the hypothesized positive association of depression with substance-related behaviors including concurrent drug use and impairment, future drug use and impairment, alcohol use and impairment, needle sharing and substance use treatment participation, and to identify moderators of these associations.

DESIGN

Meta-analysis of reports on IDUs published in English in peer-reviewed journals since 1986 that contained data on depression and substance use outcome(s) with no restrictions on range of depression scores to select the sample.

SETTING

Fifty-five reports containing 55 samples met criteria, including 42 (76%) samples from clinical venues and 13 (24%) that were community-based.

PARTICIPANTS

Mean age was 34.3 (standard deviation = 4.5) years, comprising approximately 68% men and 43% white, non-Hispanic subjects.

MEASUREMENTS

Depression was assessed with the Beck Depression Inventory, Center for Epidemiological Studies Depression Scale (CES-D) and other validated scales or diagnostic interviews. The Addiction Severity Index was the most frequently used measure of substance-related outcomes.

FINDINGS

A priori hypotheses pertaining to depression and the substance-related variables were supported, with the exception of the predicted association of depression and future drug use and impairment. Effect sizes were small. Moderating effects of gender were identified, including greater associations of depression with substance use treatment participation and needle sharing among women and a greater association of depression with future drug use and impairment among men. Effect sizes of moderators were large.

CONCLUSIONS

Depression is associated with several substance-related behaviors, and select associations are stronger according to gender. Prospective associations of depression with future drug use and impairment are not immediately evident, but could be examined in subsequent research.

Dual diagnosis in an inpatient drug-abuse detoxification unit

In Spain, detoxification in general hospitals plays an important role in the medical care of patients. We aim to provide clinicians with information on the prevalence and correlates of psychiatric co-morbidity in drug abusers in detoxification. A sample of 115 substance-abuse inpatients (mean age 31.9 +/- 6.4 years) in a Detoxification Unit of a general university hospital was studied using the Spanish version of the PRISM. Most of the patients had multiple dependence diagnoses and co-morbid axis I or axis II psychiatric disorders. Patients with dual diagnosis showed lower psychosocial functioning than patients without co-morbidity and more dependence diagnoses due to cannabis and sedatives. A total of 80% of the patients successfully completed the detoxification process. The present results enhance the value of detoxification in a general hospital as a first step of the overall treatment strategy.

The effect of persistence of cocaine use on 12-month outcomes for the treatment of heroin dependence

AIMS

To determine the effects of cocaine use across the study period on outcomes of treatment for heroin dependence 12 months post-treatment entry.

DESIGN

Longitudinal cohort (12 months). Interviews were conducted at baseline, 3 and 12 months.

SETTING

Sydney, Australia.

PARTICIPANTS

Four hundred ninety-five heroin users recruited for the Australian Treatment Outcome Study and re-interviewed at 12-month follow-up.

FINDINGS

Cocaine was widely used among treatment entrants in NSW, with almost all having a lifetime history of cocaine use and almost half having used in the month preceding baseline. While there was an overall decline in cocaine use across the study period, individual use patterns varied widely. Approximately half of the cohort did not report cocaine use at any data point, with the remainder reporting having used at one (29%), two (12%), or at all three (5%) points. Cocaine use across the study period was an independent predictor of most major treatment outcomes, with more cocaine use points predicting poorer outcome. Persistent cocaine use predicted a higher prevalence of homelessness, heroin use, daily injecting, needle sharing and injection-related health problems at 12 months as well as more extensive recent polydrug use.

CONCLUSIONS

Cocaine use was common among individuals seeking treatment for primary heroin dependence in NSW. Any cocaine use over the study period was associated with poorer outcomes in virtually all areas. Persistent cocaine use over the study period, however, appeared particularly detrimental. Cocaine use among clients should evidently be a cause for concern amongst treatment providers and may warrant being specifically targeted during treatment.

Development of a screening method for the most commonly abused anticholinergic drugs in Jordan; trihexyphenidyl, procyclidine and biperiden

A sensitive and rapid method for the simultaneous determination of three commonly abused anticholinergic drugs in Jordan; trihexyphenidyl, procyclidine, and biperiden in plasma and urine has been developed using solid phase extraction and GC-MS. Linearity was established from therapeutic to fatal concentrations of the three drugs; 5-300 ng/ml in plasma, with correlation coefficient r(2) > or = 0.9978 and 10-800 ng/ml in urine r(2) > or = 0.9993. Recoveries were in the range of 86-92% and intra-day and inter-day relative standard deviations (n = 6) were in the range of 6.6-10.3% for the three drugs at three different concentrations in plasma and urine. The base peak m/z 98 for trihexyphenidyl, m/z 84 for procyclidine, and m/z 98 and 218 for biperiden, and m/z 339 for papaverine (internal standard) were monitored at selective ion monitoring; their retention times were 8.10, 8.67 and 8.92 min, respectively, and 14.79 min for the internal standard with analysis time of 16.75 min. The limit of detection of 0.5 ng/ml was attained for trihexyphenidyl and procyclidine, while for biperiden 2.0 and 1.0 ng/ml in spiked plasma and urine, respectively. This method has been applied to forensic and authentic samples taken from abuser and patients using these drugs. The method will offer the clinicians and the legal authority the right diagnosis regarding the anticholinergic involved in any case of abuse with less than 1 h per sample (plasma or urine) from the time of receiving.

Characteristics of heroin addicts entering methadone maintenance treatment: quality of life and gender

STUDY OBJECTIVE

To provide information on MMP patient's characteristics, particularly those related with Health Related Quality of Life (HRQoL) and gender.

DESIGN

Cross-sectional study. Data were collected on socio-demographic, toxicological variables, HIV risk behaviors, and HRQoL through the Nottingham Health Profile (NHP).

PATIENTS AND SETTING

Over a 30-month period (1996--1999) Barcelona's Municipal Drug Care Centres recruited 586 patients.

MAIN RESULTS

Mean age of patients was 31 years, 70% were males and 25% were HIV-infected. Rates of unemployment, criminal records and low educational level were high. Most poly-drug users used cocaine. NHP mean score was related with poly-drug use, educational level and HIV status. Consistent condom use was related with HIV status. Females' route of administration was less likely to be injection, even though they were more frequently HIV-positive and manifested contemporary poorer general health.

CONCLUSIONS

Patients QoL was poor. Nowadays harm reduction health strategies would need to face cocaine use, and sexual risk behaviors mainly among females and sexual partners.

Methadone maintenance reduces heroin- and cocaine-induced relapse without affecting stress-induced relapse in a rodent model of poly-drug use

Although it is well established that methadone can be an effective treatment for opiate addiction, it is not clear how methadone maintenance affects cocaine use and cravings in individuals who self-administer both opiates and cocaine. In our attempt to explore the effect of methadone maintenance on the effects of cocaine, we first assessed the locomotor stimulatory effects of cocaine in rats maintained on methadone (0, 10, 20, or 30 mg/kg/day, via osmotic minipumps). Chronic methadone elevated baseline locomotion in a dose-dependent manner and did not reduce the direct stimulatory effects of cocaine (5 mg/kg). We then investigated the effects of the highest methadone maintenance dose (30 mg/kg/day) on heroin and cocaine seeking in extinction, and when it was precipitated by exposure to heroin, cocaine, or foot-shock stress in rats trained to self-administer both drugs in the same experimental context (heroin 0.05 mg/kg/inf; cocaine 0.5 mg/kg/inf, eight 3-h sessions each). In tests of reinstatement, rats responded selectively on the appropriate drug-associated lever after priming injections of heroin (0.25 mg/kg) or cocaine (20 mg/kg). Methadone maintenance blocked both cocaine- and heroin-induced reinstatement, but not stress-induced reinstatement, which was not lever selective. These results suggest that although methadone maintenance may not reduce the direct stimulatory effects of cocaine, it has the potential to reduce both spontaneous and cocaine-primed cocaine-seeking behavior.

Effects of cocaine in rats exposed to heroin

We investigated whether chronic exposure to heroin alters responses to cocaine in ways that might explain the use of cocaine by opioid addicts. To this end, the effects of cocaine (5 and 20 mg/kg) were assessed on locomotor activity of rats chronically exposed to heroin (0.0, 3.5, 7.0, and 14.0 mg/kg/day, over 14 days, via osmotic mini-pumps), or withdrawn from heroin (1 day, acute withdrawal, and 14 days, protracted withdrawal). Chronic heroin exposure, in itself, dose dependently increased locomotion and acute cocaine administration further elevated locomotor activity in a dose-dependent and additive manner. During acute withdrawal, there was a dose-dependent decrease in locomotion that was reversed by cocaine in a dose-dependent manner. During protracted withdrawal, spontaneous locomotion normalized, but rats previously exposed to heroin displayed cross-sensitization to cocaine as indicated by small, but significant, enhanced locomotor response to 5 mg/kg of cocaine, and enhanced intravenous self-administration of low doses of cocaine (0.13 mg/kg/infusion). In a separate study, we measured extracellular dopamine (DA) in the nucleus accumbens (Acb) using in vivo microdialysis before and after acute withdrawal from heroin. During chronic exposure to heroin, basal extracellular DA was elevated dose dependently, whereas in acute withdrawal, levels were not different from those in vehicle-treated rats. In response to cocaine, however, DA activity in the Acb was significantly lower in rats withdrawn from the highest dose of heroin.

Understanding polydrug use: review of heroin and cocaine co-use

The use of cocaine by heroin-dependent individuals, or by patients in methadone or buprenorphine maintenance treatment, is substantial and has negative consequences on health, social adjustment and outcome of opioid-addiction treatment. The pharmacological reasons for cocaine use in opioid-dependent individuals, however, are poorly understood and little is known about the patterns of heroin and cocaine co-use. We reviewed anecdotal evidence suggesting that cocaine is co-used with opioid drugs in a variety of different patterns, to achieve different goals. Clinical and preclinical experimental evidence indicates that the simultaneous administration of cocaine and heroin (i.e. 'speedball') does not induce a novel set of subjective effects, nor is it more reinforcing than either drug alone, especially when the doses of heroin and cocaine are high. There is mixed evidence that the subjective effects of cocaine are enhanced in individuals dependent on opioids, although it is clear that cocaine can alleviate the severity of symptoms of withdrawal from opioids. We also reviewed preclinical studies investigating possible neurobiological interactions between opioids and cocaine, but the results of these studies have been difficult to interpret mainly because the neurochemical mechanisms mediating the motivational effects of cocaine are modified by dependence on, and withdrawal from, opioid drugs. Our analysis encourages further systematic investigation of cocaine use patterns among opioid-dependent individuals and in laboratory animals. Once clearly identified, pharmacological and neuroanatomical methods can be employed in self-administering laboratory animals to uncover the neurobiological correlates of specific patterns of co-use.

Changes in HIV risk behaviors among cocaine-using methadone patients

Cocaine use among methadone patients has been related to higher prevalence of HIV risk behaviors. HIV risk behaviors for cocaine-using patients in methadone treatment (N = 207) were examined for two time periods, the current month in-treatment and the month previous to treatment admission. All needle-related and sexually-related risk behaviors (except for needle hygiene) significantly and substantially declined over the average two year time interval. Several variables were associated with needle and sexual risks in multivariate regression analyses. Dropping apparent opiate use underreporters from the analyses did not alter the results. From a harm reduction perspective, high priority should be given to retaining cocaine-using patients in methadone maintenance, intensifying in-program services for those with anti-social personality, bipolar disorder or alcoholism, as well as increasing access to needle exchanges and free condoms.

Cocaine use among heroin users in Spain: the diffusion of crack and cocaine smoking. Spanish Group for the Study on the Route of Administration of Drugs

STUDY OBJECTIVE

To describe the prevalence and patterns of use of crack and cocaine hydrochloride among heroin users in Spain. To explore if the expansion of heroin smoking is accompanied by a similar phenomenon for cocaine.

DESIGN

Cross sectional study in 1995. Face to face interviews using a structured questionnaire.

SETTING

Three cities with different prevalences of heroin use by smoking: high (Seville), intermediate (Madrid), and low (Barcelona).

PARTICIPANTS

909 heroin users, 452 in treatment and 457 out of treatment.

MAIN RESULTS

Last month prevalence of crack use was 62.3% in Seville, 19.4% in Madrid, and 7.7% in Barcelona. Most users in Madrid (86.5%) and Barcelona (100%) generally prepared their own crack, usually with ammonia as alkali; in Seville most users (69.7%) bought preprocessed crack. The proportion of users who began taking cocaine (crack or cocaine hydrochloride) by smoking has increased progressively since the seventies, rising to 74.1% in Seville, 61.5% in Madrid, and 28% in Barcelona in 1992-1995, with the earliest increase in Seville. The factors associated with crack use were: residence in Seville (odds ratio (OR) = 16.3), cocaine hydrochloride use mainly by smoking (OR = 5.0), by sniffing (OR = 2.7) or by injecting (OR = 2.5), heroin use mainly by smoking (OR = 2.8) and weekly use of cannabis (OR = 1.9).

CONCLUSIONS

In Spain smoking cocaine may be progressively diffusing from the south west to the north east, similar to what has happened with smoking heroin, but beginning later in time. The factors associated with smoking cocaine are basically ecological or cultural in nature (characteristics of the available drugs and the main route of heroin administration in each city).

Cocaine use immediately prior to entry in an inpatient heroin detoxification unit as a predictor of discharges against medical advice

Detection of benzyolecgonine, the major metabolite of cocaine, in the urinalysis conducted on the first day of an inpatient heroin detoxification treatment program was studied as a predictor of discharge against medical advice (AMA). With this aim, we conducted a chart-review procedure of 275 heroin dependents (DSM-III-R) who received methadone or dextropropoxyphene chlorhydrate to treat Opioid Withdrawal Syndrome. Data were analyzed following a case-control design. The 49 (17.8%) patients who did not complete the treatment due to discharged AMA were characterized by having achieved total heroin abstinence during fewer months from the time they began consumption of this substance to the time of hospitalization (p = .001). Moreover, those patients who requested discharge AMA were characterized by more frequent detection of benzoylecgonine in their urine on the day of admission (p = .004). The value of the odds ratio of this association was 3.81 (95% CI; 1.30 to 11.04). Lastly, noncompleters due to discharge AMA were more likely to be single than ever married (p = .037). The logistic regression model confirmed that there is a significant relationship between an AMA event and the presence of benzoylecgonine in urine upon beginning detoxification and to a shorter duration of the period of total heroin abstinence. In the discussion, the influence that recent interruption of cocaine consumption has on the decision to drop out of a detoxification program AMA is considered.

The significance of a coexisting opioid use disorder in cocaine dependence: an empirical study

This study was undertaken to compare cocaine-dependent patients with and without an opioid use disorder, in an effort to identify important clinical similarities and differences between the two groups. Ninety patients hospitalized for cocaine dependence were divided according to whether or not they had a coexisting opioid use disorder; 32 patients (35.6%) had an opioid diagnosis and 58 (64.4%) did not. The groups were compared on substance use histories, psychopathology, severity of drug-related problems, and 3-months cocaine use outcome. Patients with an opioid diagnosis had more current major depression, antisocial personality disorder, and other substance use disorders. They also had higher medical and drug scores on the Addiction Severity Index, and longer cocaine use histories. Nonetheless, 3-month cocaine use outcome was similar for both groups. Interestingly, patients with an opioid diagnosis engaged in more treatment during the follow-up period. Cocaine-dependent patients with a coexisting opioid use disorder may thus constitute a subgroup with worse prognostic characteristics, for whom differential treatments may improve outcome.

Methadone maintenance treatment in opiate dependence: a review

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The epidemiology of cocaine use in Spain

Trends and patterns of cocaine use in Spain are described with the aid of different information sources such as population surveys, the State Information System on Drug Abuse, and anthropological studies. In recent years the magnitude of cocaine supply indicators has increased greatly. High levels of last-month prevalence of cocaine use have been detected among the general population--consistently higher than those for heroin-- and cocaine consumption among heroin users has increased. Although the frequency of some health problems related to cocaine use--treatment admissions, hospital emergency admissions--has increased, it is still 30 times less than for heroin. Various hypotheses to explain these discrepancies are discussed.

Benzodiazepine use and HIV risk-taking behaviour among injecting drug users

This paper examines the prevalence of benzodiazepine use, and its relationship to other drug use and HIV risk-taking among a sample of 1245 injecting drug users (IDU). Approximately a third (36.6%) of the sample had used benzodiazepines during their last typical month of injecting. Benzodiazepine users had injected more frequently, injected more heroin and amphetamines, and had more poly-drug use than other IDU. They also had higher levels of HIV risk-taking, having shared injecting equipment more frequently and with more people. There were no differences between groups in number of sexual partners or condom use, although benzodiazepine users were more likely to have been paid for sex. The demographic and drug use variables indicate that benzodiazepine users are a more dysfunctional subgroup of IDU who require particular attention in HIV interventions.

Methadone maintenance and the human immunodeficiency virus: current issues in treatment and research

This paper examines the changes that have occurred in methadone maintenance programmes in response to the advent of HIV and the adoption of harm minimization policies, and the implications of these changes for research. A need for the use of more rigorous research methods is identified and recommendations are made that take into account both the ethical and practical difficulties of conducting research in this area. Both old, unanswered questions that have resurfaced with the recent massive growth in methadone programmes in some countries, and new questions that need to be answered in order to improve the effectiveness of methadone maintenance in the fight against HIV infection are identified as future areas in need of research.

Antagonism of acute cocaine toxicity by buprenorphine

The effect of buprenorphine pretreatment on the acute cocaine toxicity was assessed in male Swiss Webster mice. Buprenorphine pretreatment (0.15 or 0.30 mg/kg ip, 30 mins before) significantly attenuated the lethal effects of cocaine (60-140 mg/kg ip). The dose of cocaine which resulted in 50% mortality (LD50) in saline pretreated group was 100.61 mg/kg while the LD50 of cocaine in buprenorphine (0.15 and 0.3 mg/kg) pretreated groups were 113.57 and 118.16 mg/kg respectively. There was no significant change in the ratio of brain/plasma levels of cocaine in buprenorphine pretreated group when compared to the ratio from saline treated controls. Furthermore, neither naloxone (10 mg/kg ip, 15 mins before) nor naltrexone (3 mg/kg ip, 15 mins before) pretreatment affected the LD50 of cocaine. When tested 0.5, 1, 2, 4, 8 and 24 hrs after cocaine administration, sublethal dose of cocaine (80 mg/kg ip) injection resulted in significant increase in the plasma lactate dehydrogenase (LDH) levels. Buprenorphine pretreatment significantly attenuated cocaine-induced release of LDH. These results suggest that buprenorphine could be of potential advantage over naloxone in the management of cocaine and heroin ("speed ball") toxicity and in studies on the pharmacotherapy of cocaine-induced toxicity, LDH levels may be used as a biochemical marker to assess the protective effects of drugs.