Heroin self-administration by means of 'chasing the dragon': pharmacodynamics and bioavailability of inhaled heroin

Rats chasing the dragon: A new heroin inhalation method

BACKGROUND

Despite extensive human use of inhalation for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization.

NEW METHOD

Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration.

RESULTS

Ten minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure.

COMPARISON WITH EXISTING METHODS

Inhalation of directly volatilized heroin successfully produces heroin-typical effects, comparable to EDDS inhalation delivery.

CONCLUSIONS

This study shows that "chasing the dragon" methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into the middle age of rats.

Rats Chasing the Dragon: A new heroin inhalation method

Rationale

Despite extensive human use of the inhalation route for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization.

Objective

This study was designed to determine if direct volatilization of heroin hydrochloride delivers effective heroin doses to rodents.

Methods

Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration.

Results

Ten minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure.

Conclusions

This study shows that "chasing the dragon" methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into middle age of rat species.

Heroin and its metabolites: relevance to heroin use disorder

Heroin is an opioid agonist commonly abused for its rewarding effects. Since its synthesis at the end of the nineteenth century, its popularity as a recreational drug has ebbed and flowed. In the last three decades, heroin use has increased again, and yet the pharmacology of heroin is still poorly understood. After entering the body, heroin is rapidly deacetylated to 6-monoacetylmorphine (6-MAM), which is then deacetylated to morphine. Thus, drug addiction literature has long settled on the notion that heroin is little more than a pro-drug. In contrast to these former views, we will argue for a more complex interplay among heroin and its active metabolites: 6-MAM, morphine, and morphine-6-glucuronide (M6G). In particular, we propose that the complex temporal pattern of heroin effects results from the sequential, only partially overlapping, actions not only of 6-MAM, morphine, and M6G, but also of heroin per se, which, therefore, should not be seen as a mere brain-delivery system for its active metabolites. We will first review the literature concerning the pharmacokinetics and pharmacodynamics of heroin and its metabolites, then examine their neural and behavioral effects, and finally discuss the possible implications of these data for a better understanding of opioid reward and heroin addiction. By so doing we hope to highlight research topics to be investigated by future clinical and pre-clinical studies.

Drivers of absolute systemic bioavailability after oral pulmonary inhalation in humans

There are few studies in humans dealing with the relationship between physico-chemical properties of drugs and their systemic bioavailability after administration via oral inhalation route (Fpulm). Getting further insight in the determinants of Fpulm after oral pulmonary inhalation could be of value for drugs considered for a systemic delivery as a result of poor oral bioavailability, as well as for drugs considered for a local delivery to anticipate their undesirable systemic effects. To better delineate the parameters influencing the systemic delivery after oral pulmonary inhalation in humans, we studied the influence of physico-chemical and permeability properties obtained in silico on the rate and extent of Fpulm in a series of 77 compounds with or without marketing approval for pulmonary delivery, and intended either for local or for systemic delivery. Principal component analysis (PCA) showed mainly that Fpulm was positively correlated with Papp and negatively correlated with %TPSA, without a significant influence of solubility and ionization fraction, and no apparent link with lipophilicity and drug size parameters. As a result of the small sample set, the performance of the different models as predictive of Fpulm were quite average with random forest algorithm displaying the best performance. As a whole, the different models captured between 50 and 60% of the variability with a prediction error of less than 20%. Tmax data suggested a significant positive influence of lipophilicity on absorption rate while charge apparently had no influence. A significant linear relationship between Cmax and dose (R² = "0.79) highlighted that Cmax was primarily dependent on dose and absorption rate and could be used to estimate Cmax in humans for new inhaled drugs.

DARK Classics in Chemical Neuroscience: Heroin and Desomorphine

Opioids are arguably one of the most important pharmacologic classes, mainly due to their rich history, their useful and potent analgesic effects, and also, just as importantly, their "Dark Side", constituted by their reinforcing properties that have led countless of users to a spiral of addiction, biological dependence, tolerance, withdrawal syndromes, and death. Among the most significant abused and addictive known opioids are heroin and desomorphine, both synthetic derivatives of morphine that belong to the 4,5-epoxymorphinan structural chemical group of the opioid family drugs. These agents share not only structural, pharmacological, and epidemiological features but also a common geographical distribution. A drop in Afghan heroin production and its "exports" to Russia gave rise to widespread consumption of desomorphine in ex-Soviet republics during the first decade of the 21st century, representing an economical and accessible alternative for misusers to this sort of derivative. Herein we review the state of the art of history, chemistry and synthesis, pharmacology, and impact on society of these "cursed cousins".

[Foil Smoking/Heroin Inhalation]

Foil Smoking/Heroin Inhalation Abstract. Foil smoking is generally heroin consumption by inhalation. By heating an aluminum foil with a fire lighter the heroin on top of the foil starts melting and the smoke is then inhaled using a straw. Foil smoking is the second most common form of heroin consumption after the intravenous use. In contrast to the IV administration, heroin inhalation effects are delayed by a few minutes and the risk of transmission of HIV, Hepatitis or other infectious diseases is not relevant. Severe bronchospasms can occur in patients with or without prior pulmonary disease such as asthma bronchiale. One cerebral consequence of foil smoking is leukoencephalopathy, a spongiform degeneration of the white matter. This is likely triggered by the pyrolysate generated during the heating process. Multiple drug use and concomitant cigarette smoking in heroin addicts make cause-effect relationships difficult to assess. In general, the history of inhalative heroin consumption should be considered in patients presenting with any unkown pulmonary disease with severe bronchospasms as may happen in a severe asthma exacerbation.

Heroin in Malaysia and Singapore

Clandestine heroin laboratories have been a feature of the Malaysian illicit drug scene since soon after the abuse of heroin emerged in 1972. The first few clandestine heroin laboratories which synthesised heroin via the acetylation of imported morphine were uncovered in 1973 and 1977. By the mid-1980s, this type of laboratory was replaced by heroin-cutting laboratories whereby imported high-grade heroin was cut to street heroin. This was to meet the rising demand for the drug owing to the rapid escalation of the number of drug users. Over the years, the most significant change in the composition of the street heroin is the decrease in its purity from 30%-50% to 3%-5%. Caffeine has remained the major adulterant and chloroquine is detected in virtually all recent seizures.

Un Jalón, Un Volteón, y Otra Vez: High-Risk Crack Smoking Paraphernalia in México City

During the past decade, crack smoking has increased in Mexico among poor urban populations. Despite this increasing prevalence, little is known about the types of paraphernalia used and related sharing practices and physical harms. Data come from in-depth semi-structured interviews and observations with 156 current crack smokers in Mexico City. Findings reveal a complex, crack-smoking process in Mexico City that represents an interconnected structure of paraphernalia items and pipes that could contribute to detrimental health consequences. Specifically, we identify essential paraphernalia items that make the smoking of crack possible; describe the homemade construction of two categories of pipes; and detail the sharing practices and physical harms associated with these paraphernalia. Results point towards a smoking process that is embedded in impoverished urban neighborhoods sustained by an accessible street-level crack market. Discussed are the policy and intervention implications associated with reducing crack-related health consequences in Mexico and other Latin American countries.

Pyrolysis of drugs of abuse: a comprehensive review

This review summarizes the literature to date relating to pyrolysis and heated vapour ingestion of drugs of abuse. In this context, heating is referred to as smoking or pyrolysis, but these are generic descriptors that encompass numerous methods of vapour generation and inhalation. Depending on the amount of drug used, diluents and contaminants present, heating conditions, and the oxidative/reductive environment, many thermal decomposition products can be formed. In addition to the recognized hazard of rapid onset of pharmacological effects of the parent drug, thermal decomposition products may be pharmacologically active as well as acutely/chronically toxic. For example, several published reports have linked heroin smoking to a form of brain encephalopathy and to the development of movement disorders. Early qualitative studies focusing on the thermal decomposition of drugs have evolved into more complex investigations employing mass spectral identification, confirmation, and elucidation of formation mechanism. In most cases, thermal decomposition begins with cleavage of the weakest bond (often C-N) to generate free radicals that then form the most stable sterically favoured products. Several reports of rearrangements at higher temperatures have been identified and hint at an underlying complexity that arises from the variety of smoking methods and conditions. Given that many designer drugs such as synthetic cannabinoids are ingested primarily through smoking, this issue has taken on new importance.

Toxic leukoencephalopathies

Leukoencephalopathy is a syndrome of neurologic deficits, including alteration of mental status, caused by pathologic changes in the cerebral white matter. The term, toxic leukoencephalopathy, encompasses a wide variety of exposures and clinical presentations. The diagnosis in these Frontiers in Clinical Neurotoxicology syndromes is made by careful attention to the history, clinical features, and radiologic findings. This article details three of the best-defined toxic leukoencephalopathies: delayed posthypoxic leukoencephalopathy, including delayed neurologic sequelae after carbon monoxide poisoning; heroin inhalation leukoencephalopathy; and posterior reversible encephalopathy syndrome.

Staff concerns in heroin-assisted treatment centres

Heroin-assisted treatment (HAT) is a solution for improving the condition of treatment-resistant heroin addicts. Since 1994, six randomized controlled trials have concluded that HAT is more efficacious than oral methadone for severe heroin addicts. We visited seven HAT treatment centres in four countries in order to observe diacetylmorphine (DAM) administration and to study the main concerns of the staff. Nurses were concerned by the risk taken if a previously intoxicated patient received his dose of DAM. Another concern was the smuggling of DAM doses. The HAT centres face a dilemma: treating patients while at the same time allowing their risky street habits in the centre.

Craving and illicit heroin use among patients in heroin-assisted treatment

AIMS

To investigate in heroin-assisted treatment (HAT) compared to methadone maintenance treatment (MMT): the course of heroin craving and illicit heroin use, their mutual association, and their association with multi-domain treatment response.

DESIGN

RCTs on the efficacy of 12 months co-prescribed injectable or inhalable HAT compared to 12 months continued oral MMT.

SETTING

Outpatient treatment in MMT- or specialized HAT-centers in the Netherlands.

PARTICIPANTS

Chronic, treatment-refractory heroin dependent patients (n=73). STUDY PARAMETERS: General craving for heroin (Obsessive Compulsive Drug Use Scale); self-reported illicit heroin use; multi-domain treatment response in physical, mental and social health and illicit drug use.

FINDINGS

The course of heroin craving and illicit heroin use differed significantly, with strong reductions in HAT but not in MMT. General heroin craving was significantly related to illicit heroin use. Heroin craving was not and illicit heroin use was marginally related to multi-domain treatment response, but only in MMT and not in HAT.

CONCLUSIONS

Heroin craving and illicit heroin use were significantly associated and both strongly decreased in HAT but not in MMT. Craving was not related to multi-domain treatment response and illicit heroin use was marginally related to treatment response in MMT, but not in HAT. The latter was probably due to the strong reduction in illicit heroin use in most patients in HAT and the small sample size of the sub-study. It is hypothesized that the strong reductions in craving for heroin in HAT are related to the stable availability of prescribed, pharmaceutical grade heroin.

Heroin maintenance for chronic heroin-dependent individuals

BACKGROUND

Several types of medications have been used for stabilizing heroin users: Methadone, Buprenorphine and levo-alpha-acetyl-methadol (LAAM.) The present review focuses on the prescription of heroin to heroin-dependent individuals.

OBJECTIVES

To compare heroin maintenance to methadone or other substitution treatments for opioid dependence regarding: efficacy and acceptability, retaining patients in treatment, reducing the use of illicit substances, and improving health and social functioning.

SEARCH METHODS

A review of the Cochrane Central Register of Trials (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to november 2009), EMBASE (1980 to 2005) and CINAHL until 2005 (on OVID) was conducted. Personal communications with researchers in the field of heroin prescription identified ongoing trials.

SELECTION CRITERIA

Randomised controlled trials of heroin maintenance treatment (alone or combined with methadone) compared with any other pharmacological treatment for heroin-dependent individuals.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Eight studies involving 2007 patients met the inclusion criteria. Five studies compared supervised injected heroin plus flexible dosages of methadone treatment to oral methadone only and showed that heroin helps patients to remain in treatment (valid data from 4 studies, N=1388 Risk Ratio 1.44 (95%CI 1.19-1.75) heterogeneity P=0.03), and to reduce use of illicit drugs. Maintenance with supervised injected heroin has a not statistically significant protective effect on mortality (4 studies, N=1477 Risk Ratio 0.65 (95% CI 0.25-1.69) heterogeneity P=0.89), but it exposes at a greater risk of adverse events related to study medication (3 studies N=373 Risk Ratio 13.50 (95% CI 2.55-71.53) heterogeneity P=0.52). Results on criminal activity and incarceration were not possible to be pooled but where the outcome were measured results of single studies do provide evidence that heroin provision can reduce criminal activity and incarceration/imprisonment. Social functioning improved in all the intervention groups with heroin groups having slightly better results. If all the studies comparing heroin provision in any conditions vs any other treatment are pooled the direction of effect remain in favour of heroin.

AUTHORS' CONCLUSIONS

The available evidence suggests an added value of heroin prescribed alongside flexible doses of methadone for long-term, treatment refractory, opioid users, to reach a decrease in the use of illicit substances, involvement in criminal activity and incarceration, a possible reduction in mortaliity; and an increase in retention in treatment. Due to the higher rate of serious adverse events, heroin prescription should remain a treatment for people who are currently or have in the past failed maintenance treatment, and it should be provided in clinical settings where proper follow-up is ensured.

Valsalva manoeuvre effect on distribution of lung damage in heroin inhalation

This article reports the case of a patient demonstrating acute bilateral pneumonitis almost completely confined to the upper lobes as a result of inhaling heroin. We attribute this distribution to the patient performing the Valsalva manoeuvre immediately after inhaling heroin. This pattern has not been reported before and we believe it may be seen more frequently owing to a switch amongst drug users from intravenous to inhaled heroin.

Refined sewer epidemiology mass balances and their application to heroin, cocaine and ecstasy

The detection of illicit drugs in environmental matrices may be a cause for concern, both from the perspective of their potential environmental impacts and the fact that their presence in detectable concentrations would be an indicator of significant drug use. The primary goal behind recent studies on this subject has been to use measured influent concentrations of selected illicit drugs or their in vivo metabolites in the environment as a means of estimating the abuse level of these drugs and patterns of consumption. Thus-far, such calculations have hinged on the use of solitary excretion estimates from single studies of limited scope and/or studies of limited applicability. Therefore, the need exists to conduct a comprehensive meta-analysis of metabolic disposition studies to construct excretions profiles for the various illicit drugs and their in vivo metabolites. The constructed excretory profiles should not only provide mean excretion values but also indicate the expected variations in excreted fractions that arise due to differences not only in the metabolic capacity of users but also in the efficiencies of various routes of administration for a given illicit drug. Therefore, the primary goal of the research presented here was to refine sewer epidemiology extrapolation mass balances for various illicit drugs of interest by constructing their excretory profiles segregated by route-of-administration. After conducting such a study with a multi-national scope on illicit drugs including cocaine, heroin and ecstasy, the results obtained clearly indicate that extrapolation factors currently being used in literature for these drugs to enumerate prevalence of abuse required significant refinement to increase their reliability.

High rates of transitions to injecting drug use among Mexican American non-injecting heroin users in San Antonio, Texas (never and former injectors)

OBJECTIVE

To assess the incidence and rate of transition to injecting among Mexican American noninjecting heroin users.

METHODS

In a prospective cohort study of street-recruited MA-NIU in San Antonio, Texas, 2002-2005, participants were administered structured interviews and tested for Human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). The analysis sample comprised former injection drug users (last injected >6 months ago, n=47) and those who had never injected drugs and tested HCV negative (n=219). A transition to injecting was defined as the first injection of illicit drugs since baseline interview. Transition rates were based on person-years at-risk (PYAR). Proportional hazards regression was used to estimate crude and adjusted (for significant differences between former and never injectors) hazard ratios and 95% confidence intervals of injecting history on transitioning to injecting.

RESULTS

Sixty-three (24%) participants transitioned to injecting at a rate of 22.3/100 PYAR (95% CI: 17.2-28.2). Former-injectors were significantly more likely to transition than never injectors (43% or 20/47 vs. 20% or 43/219; p<0.001), and did so at a faster rate (40.4/100 PYAR, 95% CI: 24.6-60.0 vs. 18.5/100 PYAR, 95% CI: 13.4-24.4), with the crude HR=1.931 (95% CI: 1.116, 3.341) and adjusted HR=2.263 (95% CI: 1.192-4.294).

CONCLUSIONS

The rate of transitioning to injecting was high and greater among former injectors. Of particular concern is the high rate of injecting initiation among never injectors. Future analyses will examine factors associated with injecting initiation, including individual susceptibility and behaviors, social networks, and the cultural and drug market context.

Heroin maintenance for chronic heroin-dependent individuals

BACKGROUND

Several types of medications have been used for stabilizing heroin users: Methadone, Buprenorphine and levo-alpha-acetyl-methadol (LAAM.) The present review focuses on the prescription of heroin to heroin-dependent individuals.

OBJECTIVES

To compare heroin maintenance to methadone or other substitution treatments for opioid dependence regarding: efficacy and acceptability, retaining patients in treatment, reducing the use of illicit substances, and improving health and social functioning.

SEARCH STRATEGY

A review of the Cochrane Central Register of Trials (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to 2008), EMBASE (1980 to 2005) and CINAHL until 2005 (on OVID) was conducted. Personal communication with researchers in the field of heroin prescription identified other ongoing trials.

SELECTION CRITERIA

Randomised controlled trials of heroin maintenance treatment (alone or combined with methadone) were compared with any other pharmacological treatment for heroin-dependent individuals.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Eight studies involving 2007 patients were included. Results show marginal significance in favour of heroin for remaining in treatment until the end of the study (8 studies, N= 2007, RR=1.23, 95%CI=0.96-1.57; heterogeneity P < 0.01). Adverse events are significantly more frequent in the heroin group. Heroin plus methadone prescription for maintenance treatment in adult chronic opioid users who failed previous methadone treatment attempts decreases the use of other illicit substances (3 Studies, N=1289, RR=0.63, 95%CI=0.49, 0.81, heterogeneity P=0.21), and reduces the risk of being incarcerated (2 studies, N=1103, RR=0.64, 95%CI=0.51-0.79, heterogeneity P=0.31). In addition, we also found a marginally significant protective effect of heroin prescription plus methadone for the use of street heroin (3 studies, N=1512, RR=0.70, 95%CI=0.49-1.00, heterogeneity P < 0.01) and for criminal activity (4 studies, N=1377, RR=0.80, 95%CI=0.61-1.04, heterogeneity P=0.31). There was not enough power to detect statistically significant results for the risk of death (5 studies, N=1817, RR=0.77, 95%CI=0.32-1.87, heterogeneity P=0.79).

AUTHORS' CONCLUSIONS

The available evidence suggests a small added value of heroin prescribed alongside flexible doses of methadone for long-term, treatment-refractory opioid users, considering a decrease in the use of street heroin and other illicit substances, and in the probability of being imprisoned; and an increase in retention in treatment. Due to the higher rate of serious adverse events, heroin prescription should remain a treatment of last resort for people who are currently or have in the past failed maintenance treatment.

Heroin-assisted treatment in the Netherlands: History, findings, and international context

This monograph describes the history, findings and international context of heroin-assisted treatment (HAT) in the Netherlands. The monograph consists of (1) a short introduction and seven paragraphs describing the following aspects of HAT in the Netherlands: (2) history of HAT studies and implementation of routine HAT in the Netherlands; (3) main findings on efficacy, safety and cost-effectiveness from the two randomized controlled HAT trials in the Netherlands; (4) new findings from a large cohort study on the effectiveness of HAT in routine clinical practice in the Netherlands; (5) unique data on the patient's perspective of HAT; (6) data on the pharmacological and pharmaceutical basis for HAT in the Netherlands; (7) description of the registration process; and (8) account of the international context of HAT. Together, these data show that HAT can now be considered a safe and proven-effective intervention for the treatment of chronic, treatment-resistant heroin dependent patients.

Outcome of long-term heroin-assisted treatment offered to chronic, treatment-resistant heroin addicts in the Netherlands

AIMS

To describe 4-year treatment retention and treatment response among chronic, treatment-resistant heroin-dependent patients offered long-term heroin-assisted treatment (HAT) in the Netherlands.

DESIGN

Observational cohort study.

SETTING AND INTERVENTION

Out-patient treatment in specialized heroin treatment centres in six cities in the Netherlands, with methadone plus injectable or inhalable heroin offered 7 days per week, three times per day. Prescription of methadone plus heroin was supplemented with individually tailored psychosocial and medical support.

PARTICIPANTS

Heroin-dependent patients who had responded positively to HAT in two randomized controlled trials and were eligible for long-term heroin-assisted treatment (n = 149).

MEASUREMENTS

Primary outcome measures were treatment retention after 4 years and treatment response on a dichotomous, multi-domain response index, comprising physical, mental and social health and illicit substance use.

FINDINGS

Four-year retention was 55.7% [95% confidence interval (CI): 47.6-63.8%].

TREATMENT

Response was significantly better for patients continuing 4 years of HAT compared to patients who discontinued treatment: 90.4% versus 21.2% [difference 69.2%; odds ratio (OR) = 48.4, 95% CI: 17.6-159.1]. Continued HAT treatment was also associated with an increasing proportion of patients without health problems and who had stopped illicit drug and excessive alcohol use: from 12% after the first year to 25% after 4 years of HAT.

CONCLUSIONS

Long-term HAT is an effective treatment for chronic heroin addicts who have failed to benefit from methadone maintenance treatment. Four years of HAT is associated with stable physical, mental and social health and with absence of illicit heroin use and substantial reductions in cocaine use. HAT should be continued as long as there is no compelling reason to stop treatment.

Prescription of heroin for the management of heroin dependence: current status

The prescription of heroin (diamorphine) for the management of heroin dependence is a controversial treatment approach that was limited to Britain until the 1990s. Since then a number of countries have embarked upon clinical trials of this approach, and it is currently licensed and available in several European countries. To date, six randomized controlled trials (RCTs) with over 1600 patients and several cohort studies have examined injected (or inhaled) heroin treatment. This article reviews relevant clinical pharmacology, how heroin treatment programmes are delivered, and the evidence regarding safety, efficacy and cost-effectiveness from RCTs. Heroin is usually prescribed in intravenous dosages of 300-500 mg/day, divided in two or three doses. Uncommon but serious side effects include seizures and respiratory depression immediately following injection. Despite methodological shortcomings, RCTs generally indicate that heroin treatment results in a comparable retention, improved general health and psychosocial functioning, and less self-reported illicit heroin use than oral methadone treatment. Cost-effectiveness studies indicate heroin treatment to be more expensive to deliver but to result in savings in the criminal justice sector. There has been debate regarding how heroin treatment should be positioned within the range of treatment approaches for this condition. There is increasing consensus that, in countries that have robust and accessible treatment systems for heroin users, heroin treatment is suited to a minority of heroin users as a second-line treatment for those individuals who do not respond to methadone or buprenorphine treatment delivered under optimal conditions.

Pharmacokinetics and pharmacodynamics of high doses of pharmaceutically prepared heroin, by intravenous or by inhalation route in opioid-dependent patients

A pharmacokinetic-pharmacodynamic study was performed in opioid-dependent patients in the Netherlands, who were currently treated with high doses of pharmaceutically prepared heroin on medical prescription. Besides intravenous heroin, heroin was prescribed for inhalation by "chasing the dragon" method. In this technique, heroin base is heated on aluminium foil, and heroin vapours are inhaled into the lungs. Not much is known about the pharmacokinetics profile and bioavailability of this specific administration method. Therefore, a study was performed on pharmacokinetics and pharmacodynamics of heroin inhalation and intravenous use. Eleven patients who injected heroin and 9 patients who inhaled heroin entered the study. They were on steady-state heroin treatment for at least 12 months. For safety reasons, there was no crossing-over between heroin injection or inhalation. In a double-blind randomised study, 67-100-150% of the regular heroin maintenance dose was administered to each patient. Maximal single heroin dose was 450 mg. Plasma concentrations of heroin and its metabolites 6-monoacetylmorphine, morphine and morphine-glucuronides were analysed using LC-MS-MS. Blood pressure, heart rate, skin temperature and reaction time were assessed. Furthermore, visual analogue scales regarding craving and appreciation of heroin effect were scored by the subjects. Both in inhaling and injecting patients, the areas under curve of heroin and all measured metabolites were linearly related to heroin dose. Mean C(max) of heroin and its metabolites were 2-6 times lower after inhalation, than after intravenous injection. Bioavailability (F) of heroin inhalation was estimated as 52% (95% CI 44-61%). Heroin was rapidly cleared from plasma. Cl/F was 930 l/hr (95% CI 799-1061 l/hr) after intravenous administration, and 1939 l/hr (95% CI 1661-2217 l/hr) after inhalation. Heroin Cl and Vd were correlated to body weight (R(2) 15-19%). Morphine-glucuronides levels were inversely related to creatinine clearance. After heroin administration, the reaction time was significantly prolonged with 28+/-5.3 msec. in injecting and 13+/-4.9 msec. in inhaling patients. Cardiovascular changes were only mild after heroin administration. Craving-scores declined immediately after heroin administration in both administration groups. Subjective heroin effect was rated more positively in heroin inhaling than in injecting patients, despite the lower C(max) levels following heroin inhalation. In both groups, in this blinded study heroin dose increments were more appreciated than dose reductions. Increments of 50% of the regular heroin dose did not cause any serious side effect.

Determining effective methadone doses for individual opioid-dependent patients

BACKGROUND

Randomized clinical trials of methadone maintenance have found that on average high daily doses are more effective for reducing heroin use, and clinical practice guidelines recommend 60 mg/d as a minimum dosage. Nevertheless, many clinicians report that some patients can be stably maintained on lower methadone dosages to optimal effect, and clinic dosing practices vary substantially. Studies of individual responses to methadone treatment may be more easily translated into clinical practice.

METHODS AND FINDINGS

A volunteer sample of 222 opioid-dependent US veterans initiating methadone treatment was prospectively observed over the year after treatment entry. In the 168 who achieved at least 1 mo of heroin abstinence, methadone dosages on which patients maintained heroin-free urine samples ranged from 1.5 mg to 191.2 mg (median = 69 mg). Among patients who achieved heroin abstinence, higher methadone dosages were predicted by having a diagnosis of posttraumatic stress disorder or depression, having a greater number of previous opioid detoxifications, living in a region with lower average heroin purity, attending a clinic where counselors discourage dosage reductions, and staying in treatment longer. These factors predicted 42% of the variance in dosage associated with heroin abstinence.

CONCLUSIONS

Effective and ineffective methadone dosages overlap substantially. Dosing guidelines should focus more heavily on appropriate processes of dosage determination rather than solely specifying recommended dosages. To optimize therapy, methadone dosages must be titrated until heroin abstinence is achieved.

Heroin maintenance treatment for chronic heroin-dependent individuals: A Cochrane systematic review of effectiveness

The provision of prescribed heroin to chronic heroin-dependent individuals failing other treatments has been supported during the last 70 years on the ground that the first goal of interventions on drug users is to keep them in treatment to protect them from criminal activities and to promote social integration. To assess heroin prescription effectiveness, we conducted a Cochrane systematic review of all relevant randomized controlled trials. We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Library and contacted leading researchers for ongoing studies. We found 19 eligible studies, of which 4 met our inclusion criteria (577 patients). In 1 study, patients in the heroin arm remained in treatment longer than those in the methadone arm (n = 96, RR = 2.82, 95% CI = 1.70-4.68); in 2 studies, there was no difference; and in 1 study, patients given heroin left the study earlier than those given methadone (n = 235, RR = 0.79, 95% CI = 0.68-0.90). Heroin was more effective than methadone in refraining people from using street heroin in 2 studies (n = 96, RR = 1.10, 95% CI = 0.79-1.53; n = 51, RR = 0.33, 95% CI = 0.15-0.72). In 1 study, heroin reduced the risk of being charged (RR = 0.32, 95% CI = 0.14-0.78); 2 studies showed no difference, and another 2 studies adopted a multidomain outcome enclosing criminal offense and social functioning and found improvements with heroin + methadone over methadone only. It is unclear if heroin attracts people in treatment; those in treatment use less street heroin and are likely to have less criminal activities. This review systematizes and compares studies showing some inconsistencies between their aims, their adopted outcomes, and their conclusions drawn from results.

Population Pharmacokinetics of Heroin and its Major Metabolites

BACKGROUND

In several European countries and in Canada, clinical trials are being conducted in which heroin-addicted patients are treated with pharmaceutically prepared heroin in order to reduce the destructive behaviour that is so often associated with this drug.

OBJECTIVE

To develop an integrated population pharmacokinetic model for heroin (diamorphine) and its pharmacodynamically active metabolites 6-acetylmorphine, morphine, morphine-3-glucuronide and morphine-6-glucuronide. Additionally, the influence on heroin pharmacokinetics of several covariates that are typical for this population was determined.

METHOD

Plasma concentration data from 106 heroin-dependent patients in The Netherlands (74 heroin inhalers and 32 injectors) were obtained. The 'chasing the dragon' technique was used for inhalation, in which the fumes of heroin base, heated on aluminum foil, were inhaled. Heroin doses varied between 66 and 450 mg. Heroin, 6-acetylmorphine and morphine data were fitted simultaneously using sequential two-compartment models. Morphine-3-glucuronide and morphine-6-glucuronide data were fitted separately to one-compartment models. All data analysis was performed using nonlinear mixed-effect modelling.

RESULTS

The bioavailability of inhaled heroin was estimated to be 53% (95% CI 43.7, 62.3). The terminal half-lives of heroin and 6-acetylmorphine were estimated to be 7.6 and 21.8 minutes, respectively. The clearances of morphine and the morphine-glucuronides were estimated to be 73.6 L/h (95% CI 62.8, 84.4) and between 6 and 10 L/h, respectively. The terminal half-life of 6-acetylmorphine was 13% lower in cocaine users (p < 0.05). No other significant relationships between covariates and pharmacokinetic parameters were discovered.

CONCLUSIONS

Pharmacokinetic parameters of heroin and its five major metabolites were assessed simultaneously in one integrated model. Covariate analyses revealed that sex, bodyweight, benzodiazepine use and creatinine clearance (>60 mL/min) do not need to be taken into account in the medical prescription of pharmaceutically prepared heroin for the treatment of heroin dependency.

Development of pharmaceutical heroin preparations for medical co-prescription to opioid dependent patients

Presently, there is a considerable interest in heroin-assisted treatment: co-prescription of heroin to certain subgroups of chronic, treatment-resistant, opioid dependent patients. In 2002, nine countries had planned (Australia, Belgium, Canada, France, Spain) or ongoing (Germany, The Netherlands, Switzerland, United Kingdom) clinical trials on this subject. These trials (and the routine heroin-assisted treatment programs that might result) will need pharmaceutical heroin (diacetylmorphine) to prescribe to the patients. Research into the development of pharmaceutical forms of heroin for prescription to addicts can benefit from the large amount of knowledge that already exists regarding this substance. Therefore, in this paper we review the physicochemical and pharmaceutical properties of diacetylmorphine and the clinically investigated routes of administration, as well as routes of administration utilised on the street in the context of developing pharmaceutical heroin formulations for prescription to addicts. Patient acceptability of the formulation is essential, because heroin-assisted treatment is aimed at treatment-resistant addicts, who often have to be encouraged to participate (or to maintain participation) in a treatment program. This means that the most suitable products would have pharmacokinetic profiles mimicking that of diacetylmorphine for injection, with rapid peak concentrations of diacetylmorphine and 6-acetylmorphine, ensuring the 'rush effect' and the sustained presence of morphine(-6-glucuronide) creating the prolonged euphoria. Diacetylmorphine for inhalation after volatilisation (via 'chasing the dragon') seems to be a suitable candidate, while intranasal and oral diacetylmorphine are currently thought to be unsuitable. However, oral and intranasal delivery systems might be improved and become suitable for use by heroin dependent patients.

Chasing "chasing the dragon" with MRI: leukoencephalopathy in drug abuse

Spongiform leukoencephalopathy is a rare complication from inhalation of heated heroin vapour, a practice called "chasing the dragon". The MRI findings are considered pathognomonic, making MRI important for diagnosis. This is especially true in busy urban emergency departments where a variety of patients may present obtunded, unable or unwilling to provide a useful history. Even though the MR pattern of "chasing" toxicity is considered pathognomonic, there are mimickers. We compare the MRI findings of two classic cases of chasing leukoencephalopathy with one case of mimickery from cocaine exposure only. All three cases had diffuse symmetrical white matter changes. MR spectroscopy (MRS) in chasing patients showed increased lactic acid and myo-inositol, decreased N-acetyl aspartate and creatine, normal to slightly decreased choline, and normal lipid peak. MRS in the cocaine exposure patient showed marked increase in lactic acid and lipids. MR perfusion in one chasing patient was normal.

IN CONCLUSION

(1) All three cases have MR findings suggestive of spongiform leukoencephalopathy. MRS may help differentiate toxicity due to inhaled heroin from other non-heroin related toxicities. (2) Discordance between perfusion and spectroscopy in one chasing patient adds evidence that the disease is due to impaired energy metabolism at the cellular level. (3) MR findings of spongiform leukoencephalopathy secondary to chasing heroin can progress despite apparent abstinence of the drug and during clinical improvement, suggesting the MR changes may represent an evolving injury.

Pharmaceutical heroin for inhalation: Thermal analysis and recovery experiments after volatilisation

Pharmaceutical heroin for inhalation was developed for a clinical trial on co-prescription of heroin and methadone to chronic treatment-resistant heroin addicts. Diacetylmorphine base was selected as the active pharmaceutical ingredient for this product with caffeine anhydrate added as an excipient. Differential scanning calorimetry and thermogravimetric analysis showed that addition of caffeine resulted in a lower melting temperature and a higher volatilisation rate for the mixture than for diacetylmorphine base alone. Recovery experiments showed that 40.8+/-5.3% of diacetylmorphine base could be found in smoke condensate after volatilisation of diacetylmorphine-caffeine tablets. All of the caffeine from each tablet was recovered unchanged in the fumes, while 85.6% of the diacetylmorphine from each tablet was recovered, either unchanged in the fumes or as non-volatilised residue. Recovery was found to be reproducible and only small differences were found between the tablet types. The experimental set-up was found to efficiently collect the vapours resulting from heating the powder. Under the tested experimental conditions, no evidence was found that degradation products of diacetylmorphine or caffeine, other than 6-acetylmorphine (5.9%) had volatilised, even though a decomposed residue was present after heating diacetylmorphine-caffeine samples. Diacetylmorphine-caffeine was found to be a suitable basis for pharmaceutical heroin to be used by 'chasing the dragon'.

Pharmacokinetic comparison of two methods of heroin smoking: 'chasing the dragon' versus the use of a heating device

In preparation for a trial on co-prescription of inhalable heroin and methadone, two methods for inhalation of heroin/caffeine tablets were compared: the commonly used method of 'chasing the dragon' and a standardised procedure for inhalation of volatilised heroin, using a heating device. Five male addicts inhaled a tablet of smokable heroin daily for 5 days, alternating the inhalation method. Plasma concentrations of heroin, 6-acetylmorphine, morphine and morphine-3- and -6-glucuronide were determined using a liquid chromatography method with tandem mass spectrometric detection. The exposure to heroin and its metabolites (expressed as areas under the concentration-time curve) was significantly lower after smoking via the heating device than after 'chasing the dragon': heroin 80% and 6-acetylmorphine 73% lower (p < 0.05). Maximal concentrations of heroin and 6-acetylmorphine were also 80% and 70% lower (p < 0.05) after using the heating device. 'Chasing the dragon' is a more efficient inhalation method than inhalation via the heating device.

Heroin maintenance for chronic heroin dependents

BACKGROUND

Many medications have been used for stabilizing heroin users: Methadone, Buprenorphine and LAAM. The present review focus on the prescription of heroin to heroin dependents.

OBJECTIVES

To assess the efficacy and acceptability of heroin maintenance versus methadone or other substitution treatments for opioid dependence, in retaining patients in treatment; reducing the use of illicit substances and improving health and social functioning.

SEARCH STRATEGY

The Cochrane Central Register of Trials (CENTRAL) issue 1, 2005; MEDLINE 1966-2005, EMBASE 1980-2005 and CINAHL till 2005 (on OVID) were searched. There was no language or publication year restrictions. Many researchers were contacted for information.

SELECTION CRITERIA

Randomised controlled trials of heroin (alone or combined with methadone) maintenance treatment compared with any other pharmacological treatments for heroin dependents.

DATA COLLECTION AND ANALYSIS

The trials were independently assessed for inclusion and methodological quality by the reviewers. Data were extracted independently and double checked. Studies were not pooled together because of heterogeneity.

MAIN RESULTS

2400 references were obtained and 20 studies were eligible, 4 met the inclusion criteria for a total of 577 patients. The studies could not be analysed cumulatively because of heterogeneity of interventions and outcomes. Retention in treatment: no groups difference was found in two studies; one study (N=96) found RR=2.82 (95% CI 1.70-4.68) favouring heroin; one study (N=235) found RR 0.79 (95%CI 0.68-0.90) favouring methadone. Relapse to illegal heroin use (self- reported): in one study people using heroin in treatment was 64% (heroin group)and 59% (methadone group); in the other study the RR of heroin use was 0.33 (95%CI 0.15-0.72) favouring heroin. Criminal offence: one study showed the potential of heroin prescription in reducing the risk of being charged RR 0.32 (95% CI 0.14-0.78). Social functioning: two studies did not show statistical difference between intervention groups, and two studies considered criminal offence and social functioning as part of a multidomain outcome measure showing improvements among those treated with heroin plus methadone over those on methadone only.

AUTHORS' CONCLUSIONS

No definitive conclusions about the overall effectiveness of heroin prescription is possible. Results favouring heroin treatment come from studies conducted in countries where easily accessible Methadone Maintenance Treatment at effective dosages is available. In those studies heroin prescription was addressed to patients who had failed previous methadone treatments. The present review contains information about ongoing trials which results will be integrated as soon as available.

What can the Swiss and Dutch trials tell us about the potential risks associated with heroin prescribing?

Following on from last edition's Harm Reduction Digest on drug consumption facilities this Digest investigates what can be learnt from the Swiss and Dutch trials of heroin prescribing about the unintended consequences of this controversial intervention to reduce heroin-related harm. The authors of the paper bring considerable experience in the implementation and evaluation of such schemes in Europe and their consideration in Australia. The paper systematically addresses concerns about heroin prescribing and suggests further research to respond to some unanswered questions.

Population Pharmacokinetics of Caffeine and its Metabolites Theobromine, Paraxanthine and Theophylline after Inhalation in Combination with Diacetylmorphine

The stimulant effect of caffeine, as an additive in diacetylmorphine preparations for study purposes, may interfere with the pharmacodynamic effects of diacetylmorphine. In order to obtain insight into the pharmacology of caffeine after inhalation in heroin users, the pharmacokinetics of caffeine and its dimethylxanthine metabolites were studied. The objectives were to establish the population pharmacokinetics under these exceptional circumstances and to compare the results to published data regarding intravenous and oral administration in healthy volunteers. Diacetylmorphine preparations containing 100 mg of caffeine were used by 10 persons by inhalation. Plasma concentrations of caffeine, theobromine, paraxanthine and theophylline were measured by high performance liquid chromatography. Non-linear mixed effects modelling was used to estimate population pharmacokinetic parameters. The model was evaluated by the jack-knife procedure. Caffeine was rapidly and effectively absorbed after inhalation. Population pharmacokinetics of caffeine and its dimethylxanthine metabolites could adequately and simultaneously be described by a linear multi-compartment model. The volume of distribution for the central compartment was estimated to be 45.7 l and the apparent elimination rate constant of caffeine at 8 hr after inhalation was 0.150 hr(-1) for a typical individual. The bioavailability was approximately 60%. The presented model adequately describes the population pharmacokinetics of caffeine and its dimethylxanthine metabolites after inhalation of the caffeine sublimate of a 100 mg tablet. Validation proved the stability of the model. Pharmacokinetics of caffeine after inhalation and intravenous administration are to a large extent similar. The bioavailability of inhaled caffeine is approximately 60% in experienced smokers.

Matching of treatment-resistant heroin-dependent patients to medical prescription of heroin or oral methadone treatment: results from two randomized controlled trials

AIMS

To investigate which baseline patient characteristics of treatment-resistant heroin addicts differentially predicted treatment response to medical heroin prescription compared to standard methadone maintenance treatment.

DESIGN

Two open-label randomized controlled trials; pooled data.

SETTING

Methadone maintenance programmes and heroin treatment centres in six cities in the Netherlands.

PARTICIPANTS

Four hundred and thirty heroin addicts.

INTERVENTION

Methadone plus injectable heroin or methadone plus inhalable heroin compared to methadone alone prescribed over 12 months: heroin maximum 1000 mg per day, methadone maximum 150 mg per day.

MAIN OUTCOME MEASURE

Dichotomous, multi-domain response index, including validated indicators of physical health, mental status and social functioning.

FINDINGS

Data of the inhalable and injectable heroin trials were pooled. Intention-to-treat analysis showed that treatment with medically prescribed heroin plus methadone was significantly more effective (51.8% response) than standard methadone maintenance treatment (28.7%) (95% CI of response difference: 14.1-32.2%). Multivariate logistic regression analyses showed that only one of all baseline characteristics was predictive of a differential treatment effect: patients who had previously participated in abstinence-orientated treatment responded significantly better to heroin-assisted treatment than to methadone treatment (61% versus 24%), while patients without experience in abstinence-orientated treatment did equally well in heroin-assisted or methadone maintenance treatment (39% and 38%, respectively).

CONCLUSIONS

The effect of heroin-assisted treatment is not dependent on clinical characteristics, with the exception of previous abstinence-orientated treatment: medical prescription of heroin is most effective for those patients who have previously participated in abstinence-orientated treatment.

Process characterisation, optimisation and validation of production of diacetylmorphine/caffeine sachets: a design of experiments approach

Powder filled sachets containing a 3:1 (w/w) powder mixture of diacetylmorphine base and caffeine anhydrate were developed as a dosage form for smokable heroin used for the treatment of chronic, treatment-resistant heroin addicts. The powder mixture was filled into sachets using a micro dose auger filler machine. The goal of this study was to identify the most important process variables that influence precision of dosing. Five variables were tested: auger speed, agitator speed, hopper fill level, dose interval, and dose. An experimental design was used to study the effects of each of these variables, including possible non-linear and interaction effects. A 9-term regression model was constructed, explaining 94% of the observed variation in dose weight variation coefficient. Dose, agitator speed and hopper fill level were the most important variables. The regression model was used to identify optimal settings of the variables for four sachet doses intended for routine manufacture. The results of four test batches manufactured with these optimised settings showed that accurate (accuracy: 99.0-101.0%) and precise (CV: 3.2-5.3%) filling of diacetylmorphine/caffeine sachets is possible using the micro dose auger filler machine.

Development and Manufacture of Diacetylmorphine/Caffeine Sachets for Inhalation Via ‘Chasing the Dragon’ by Heroin Addicts

In 1998, two clinical trials were started in The Netherlands to evaluate the effect of coprescription of heroin and methadone on the mental and physical health and social functioning of chronic, treatment-resistant, heroin-dependent patients. Since 75-85% of the heroin addicts in The Netherlands use their heroin by "chasing the dragon," one of the two study arms concerned the coprescription of inhalable heroin. A pharmaceutical dosage form for inhalable heroin was developed for this trial, consisting of a 3:1 powder mixture of diacetylmorphine base and caffeine anhydrate. We describe the manufacturing process that was developed for filling sachets with this mixture in four dosages using a micro dose auger filler. In order to control product quality, in-process controls were developed to monitor the filling process and quality control tests were performed on the finished product. In-process control results have shown the filling process to be accurate and precise. The diacetylmorphine/caffeine sachets were shown to comply with the specifications for content and uniformity of mass. The finished product was found to be stable for 2 years when stored at 25 degrees C, 60% relative humidity and for 6 months when stored at 40 degrees C, 75% relative humidity.

A Fatal Case of Spongiform Leukoencephalopathy Linked to “Chasing the Dragon”

BACKGROUND

"Chasing the dragon" involves placing heroin on aluminum foil, heating it from below with a flame, and inhaling the pyrolysate through a straw. It has rarely been associated with the development of a progressive spongiform leukoencephalopathy.

CASE REPORT

A 43-year-old woman presented with 2 weeks of bizarre behavior, forgetfulness, and slowed speech and movements. Serum, cerebrospinal fluid, and head computed tomography (CT) scan were normal. The patient progressed to coma and expired during week 4 of hospital admission. The family confirmed that she "chased the dragon." Cause of death at post mortem examination was spongiform leukoencephalopathy.

CONCLUSION

The diagnosis of heroin pyrolysate-induced spongiform leukoencephalopathy should be considered in a patient with a history of "chasing the dragon" and neurobehavioral changes, including confusion, apathy, cerebellar signs, and motor restlessness.

Medical prescription of heroin to treatment resistant heroin addicts: two randomised controlled trials

OBJECTIVE

To determine whether supervised medical prescription of heroin can successfully treat addicts who do not sufficiently benefit from methadone maintenance treatment.

DESIGN

Two open label randomised controlled trials.

SETTING

Methadone maintenance programmes in six cities in the Netherlands.

PARTICIPANTS

549 heroin addicts.

INTERVENTIONS

Inhalable heroin (n = 375) or injectable heroin (n = 174) prescribed over 12 months. Heroin (maximum 1000 mg per day) plus methadone (maximum 150 mg per day) compared with methadone alone (maximum 150 mg per day). Psychosocial treatment was offered throughout.

MAIN OUTCOME MEASURES

Dichotomous, multidomain response index, including validated indicators of physical health, mental status, and social functioning.

RESULTS

Adherence was excellent with 12 month outcome data available for 94% of the randomised participants. With intention to treat analysis, 12 month treatment with heroin plus methadone was significantly more effective than treatment with methadone alone in the trial of inhalable heroin (response rate 49.7% v 26.9%; difference 22.8%, 95% confidence interval 11.0% to 34.6%) and in the trial of injectable heroin (55.5% v 31.2%; difference 24.3%, 9.6% to 39.0%). Discontinuation of the coprescribed heroin resulted in a rapid deterioration in 82% (94/115) of those who responded to the coprescribed heroin. The incidence of serious adverse events was similar across treatment conditions.

CONCLUSIONS

Supervised coprescription of heroin is feasible, more effective, and probably as safe as methadone alone in reducing the many physical, mental, and social problems of treatment resistant heroin addicts.

Beta-phenylethylamines and the isoquinoline alkaloids

This review covers beta-phenylethylamines and isoquinoline alkaloids and compounds derived from them, including further products of oxidation, condensation with formaldehyde and rearrangement, some of which do not contain an isoquinoline system, together with naphthylisoquinoline alkaloids, which have a different biogenetic origin. The occurrence of the alkaloids, with the structures of new bases, together with their reactions, syntheses and biological activities are reported. The literature from July 2001 to June 2002 is reviewed, with 581 references cited.

The resurgence and abuse of heroin by children in the United States

Heroin, one of the most addictive and "hardest" drugs of abuse, carries significant morbidity and mortality. Although its use is usually associated with the adult population in the United States, the last decade has witnessed a decrease in the median age of heroin users. An increase in the availability of inexpensive and pure heroin that could be snorted rather than injected made the drug accessible to adolescents and reduced the fear associated with the transmission of the human immunodeficiency virus (HIV). Because of the atypical demographics and the alternative drug use patterns, this young population of heroin users is not easily identified by parents or by healthcare providers. Lack of social support or access to healthcare prevents young heroin users from participation in detoxification programs, suggesting that changes may be needed in our healthcare and social systems to properly target and provide care to the youngest heroin abusers.

Heroin maintenance for chronic heroin dependents

BACKGROUND

Dependent heroin users are characterised by the persistence of use in spite of the difficulties they experience with health, law, social achievements and personal relationships. The present review will consider maintenance treatment in which the patients enter programs of pharmacological administration tailored to achieve patient stabilisation. Many medications have been used for this purpose such as: Methadone, Buprenorphine and LAAM. The present review will focus on maintenance treatment through the prescription of heroin.

OBJECTIVES

To assess the efficacy and acceptability of heroin maintenance versus methadone or other substitution treatments for opioid dependence, in retaining patients in treatment; reducing the use of illicit substances and improving health and social functioning.

SEARCH STRATEGY

The Cochrane Central Register of Trials (CENTRAL) issue 4, 2002; MEDLINE (on Silver Platter) 1966-2002; EMBASE (on OVID) 1980-2000 and CINAHL till 2000 were searched. There was no language or publication year restrictions. Many researchers were contacted for information.

SELECTION CRITERIA

Randomised controlled trials of heroin (alone or combined with methadone) maintenance treatment compared with any other pharmacological treatments.

DATA COLLECTION AND ANALYSIS

The trials were independently assessed for inclusion and methodological quality by the reviewers. Data were extracted independently and double checked. Studies were not pooled together because of heterogeneity.

MAIN RESULTS

2400 references were obtained and 20 studies were eligible, 4 met the inclusion criteria for a total of 577 patients. The studies included could not be analysed cumulatively because of heterogeneity of interventions and outcomes considered. Two studies compared injected heroin to oral methadone for 1 year (270 patients) but considered different outcomes; one study compared injected heroin and methadone to oral methadone for 6 months (51 patients); and one compared inhaled heroin and methadone to oral methadone for 1 year (235 patients). Retention in treatment: in two studies there was no statistical difference between groups; one study (N=90) had a RR=2.49 (95% CI 1.51-4.10) in favour of heroin; one study (N=235) had a RR 0.79 (95%CI 0.68-0.90) in favour of methadone. Relapse to illegal heroin use, based on self report: in one study the proportion of people still using heroin were 64% in the heroin group, 59% methadone group; in the other study the RR was 0.33 (95%CI 0.15-0.72) in favour of heroin. The remaining studies did not provide the data. Criminal offence: one of the two studies which provided details about this showed the potential of heroin prescription in reducing the risk of being charged RR 0.32 (95% CI 0.14-0.78). Social functioning: the two studies reporting this outcome did not show statistical difference between intervention groups. The two most recent studies considered criminal offence and social functioning as part of a multidomain outcome measure and showed higher improvement among those treated with heroin plus methadone over those on methadone only.

REVIEWER'S CONCLUSIONS

No definitive conclusions about the overall effectiveness of heroin prescription is possible because of non-comparability of the experimental studies available to be included in this review. Results favouring heroin treatment come from studies conducted in countries where the treatment system is comprehensive and easy accessible Methadone Maintenance Treatment at effective dosages is available. In those studies heroin prescription was addressed to patients who had failed previous methadone treatments.