Strategies to improve compliance with narcotic antagonists

Naltrexone treatment for opioid dependence: does its effectiveness depend on testing the blockade?

BACKGROUND

FDA approval of long-acting injectable naltrexone (Vivitrol) for opioid dependence highlights the relevance of understanding mechanisms of antagonist treatment. Principles of learning suggest an antagonist works through extinguishing drug-seeking behavior, as episodes of drug use ("testing the blockade") fail to produce reinforcement. We hypothesized that opiate use would moderate the effect of naltrexone, specifically, that opiate-positive urines precede dropout in the placebo group, but not in the active-medication groups.

METHODS

An 8-week, double-blind, placebo-controlled trial (N=57), compared the efficacy of low (192 mg) and high (384 mg) doses of a long-acting injectable naltrexone (Depotrex) with placebo (Comer et al., 2006). A Cox proportional hazard model was fit, modeling time-to-dropout as a function of treatment assignment and urine toxicology during treatment.

RESULTS

Interaction of opiate urines with treatment group was significant. Opiate-positive urines predicted dropout on placebo and low-dose, but less so on high-dose naltrexone, where positive urines were more likely followed by sustained abstinence. Among patients with no opiate-positive urines, retention was higher in both low- and high-dose naltrexone conditions, compared to placebo.

CONCLUSIONS

Findings confirm that injection naltrexone produces extinction of drug-seeking behavior after episodes of opiate use. Adequate dosage appears important, as low-dose naltrexone resembled the placebo group; opiate positive urines were likely to be followed by dropout from treatment. The observation of high treatment retention among naltrexone-treated patients who do not test the blockade, suggests naltrexone may also exert direct effects on opiate-taking behavior that do not depend on extinction, perhaps by attenuating craving or normalizing dysregulated hedonic or neuroendocrine systems.

Assessing the usefulness of health data linkage in obtaining adverse event data in a randomised controlled trial of oral and implant naltrexone in the treatment of heroin dependence

Background

The completeness of self-reported serious adverse events (SAEs) in clinical trials can be reduced by inaccuracies in subject reporting and lost to follow-up.

Purpose

This study assesses the usefulness of a health data linkage system in obtaining SAE data in a randomised controlled study of oral and implant naltrexone.

Methods

SAEs were collected from 68 heroin-dependent subjects during a randomised controlled trial of oral and implant naltrexone with follow-up to 26 weeks. Patient self-report data were cross-matched against hospital and emergency department (ED) attendances for the same period using a health data linkage system.

Results

A total of 29 hospital admissions and 74 ED attendances were identified using health data linkage. Of these, 12 (41.4%) hospital admissions and 50 (67.7%) of ED attendances had not been reported as SAE in the randomised controlled trial. In subjects participating in the trial at the time of the event, there was a 1.25-fold increase in the number of hospital admissions and a 2.25-fold increase in the number of ED attendances recorded using data linkage. Overall (including withdrawn subjects or those lost to follow-up), there was a 1.71-fold increase in hospital admission and a 3.09-fold increase in ED attendance recorded.

Limitations

The use of data linkage should not be used as a replacement for thorough follow-up, as the datasets can take substantial periods to update, making them a poor substitute for real-time follow-up. Additionally, some SAEs such as life-threatening events that do not involve ED or hospital attendance may be overlooked as would SAEs that occurred outside the dataset’s range, for example, interstate or overseas.

Conclusions

Health data linkage can be used to effectively reduce the extent of missing health data in a clinical trial.

The use of incentives to reinforce medication adherence

OBJECTIVE

Poor medication adherence is a longstanding problem, and is especially pertinent for individuals with chronic conditions or diseases. Adherence to medications can improve patient outcomes and greatly reduce the cost of care. The purpose of the present review is to describe the literature on the use of incentives as applied to the problem of medication adherence.

METHODS

We conducted a systematic review of peer-reviewed empirical evaluations of incentives provided to patients contingent upon medication adherence.

RESULTS

This review suggests that incentive-based medication adherence interventions can be very effective, but there are few controlled studies. The studies on incentive-based medication adherence interventions most commonly feature patients taking medication for drug or alcohol dependence, HIV, or latent tuberculosis. Across studies that reported percent adherence comparisons, incentives increased adherence by a mean of 20 percentage points, but effects varied widely. Cross-study comparisons indicate a positive relationship between the value of the incentive and the impact of the intervention. Post-intervention evaluations were rare, but tended to find that adherence effects diminish after the interventions are discontinued.

CONCLUSIONS

Incentive-based medication adherence interventions are promising but understudied. A significant challenge for research in this area is the development of sustainable and cost-effective long-term interventions.

Opioid detoxification and naltrexone induction strategies: recommendations for clinical practice

BACKGROUND

Opioid dependence is a significant public health problem associated with high risk for relapse if treatment is not ongoing. While maintenance on opioid agonists (i.e., methadone, buprenorphine) often produces favorable outcomes, detoxification followed by treatment with the μ-opioid receptor antagonist naltrexone may offer a potentially useful alternative to agonist maintenance for some patients.

METHOD

Treatment approaches for making this transition are described here based on a literature review and solicitation of opinions from several expert clinicians and scientists regarding patient selection, level of care, and detoxification strategies.

CONCLUSION

Among the current detoxification regimens, the available clinical and scientific data suggest that the best approach may be using an initial 2-4 mg dose of buprenorphine combined with clonidine, other ancillary medications, and progressively increasing doses of oral naltrexone over 3-5 days up to the target dose of naltrexone. However, more research is needed to empirically validate the best approach for making this transition.

Current and potential pharmacological treatment options for maintenance therapy in opioid-dependent individuals

Opioid dependence, manifesting as addiction to heroin and pharmaceutical opioids is increasing. Internationally, there are an estimated 15.6 million illicit opioid users. The global economic burden of opioid dependence is profound both in terms of HIV and hepatitis C virus transmission, direct healthcare costs, and indirectly through criminal activity, absenteeism and lost productivity. Opioid agonist medications, such as methadone and buprenorphine, that stabilize neuronal systems and provide narcotic blockade are the most effective treatments. Prolonged provision of these medications, defined as maintenance treatment, typically produces improved outcomes when compared with short-duration tapers and withdrawal. The benefits of opioid agonist maintenance include decreased illicit drug use, improved retention in treatment, decreased HIV risk behaviours and decreased criminal behaviour. While regulations vary by country, these medications are becoming increasingly available internationally, especially in regions experiencing rapid transmission of HIV due to injection drug use. In this review, we describe the rationale for maintenance treatment of opioid dependence, discuss emerging uses of opioid antagonists such as naltrexone and sustained-release formulations of naltrexone and buprenorphine, and provide a description of the experimental therapies.

Pharmacological enhancement of naltrexone treatment for opioid dependence: a review

PURPOSE: Opioid dependence (OD) is a serious and growing clinical condition with increasing social costs that requires expanding treatment beyond opioid agonist substitution. The opioid antagonist naltrexone has displayed a remarkable association of theoretical effectiveness and poor clinical utility in treating OD due to noncompliant behavior and low acceptability among patients, only partly modified by psychosocial interventions. We reviewed pharmacological studies, including naltrexone depot formulations and combination treatments. METHOD: We searched PubMed for clinical studies on the use of naltrexone implants and slow-release injections in OD, and investigations using adjunct medications to improve naltrexone maintenance therapy of OD. We discussed the results in view of their application to the clinical practice. RESULTS: Significant reduction in opioid use and improved retention in treatment have been found in several studies using depot naltrexone formulations, some of which are controlled clinical trials. Pilot investigations have gathered initial positive results on the use of naltrexone in combination with serotonin reuptake inhibitors, α-2 adrenergic, opioid, and γ-aminobutyric acid agonist medications. CONCLUSION: Current evidence suggests that more research on effectiveness and safety is needed in support of depot naltrexone treatment for OD. Further research comparing slow-release with oral naltrexone and opioid agonist medications will help characterize the role of opioid antagonist-mediated treatment of OD. Preliminary investigations on naltrexone combination treatments suggest the opportunity to continue study of new mixed receptor activities for the treatment of OD and other drug addictions.

Human behavioral pharmacology, past, present, and future: symposium presented at the 50th annual meeting of the Behavioral Pharmacology Society

A symposium held at the 50th annual meeting of the Behavioral Pharmacology Society in May 2007 reviewed progress in the human behavioral pharmacology of drug abuse. Studies on drug self-administration in humans are reviewed that assessed reinforcing and subjective effects of drugs of abuse. The close parallels observed between studies in humans and laboratory animals using similar behavioral techniques have broadened our understanding of the complex nature of the pharmacological and behavioral factors controlling drug self-administration. The symposium also addressed the role that individual differences, such as sex, personality, and genotype play in determining the extent of self-administration of illicit drugs in human populations. Knowledge of how these factors influence human drug self-administration has helped validate similar differences observed in laboratory animals. In recognition that drug self-administration is but one of many choices available in the lives of humans, the symposium addressed the ways in which choice behavior can be studied in humans. These choice studies in human drug abusers have opened up new and exciting avenues of research in laboratory animals. Finally, the symposium reviewed behavioral pharmacology studies conducted in drug abuse treatment settings and the therapeutic benefits that have emerged from these studies.

Cocaine vaccine for the treatment of cocaine dependence in methadone-maintained patients: a randomized, double-blind, placebo-controlled efficacy trial

CONTEXT

Cocaine dependence, which affects 2.5 million Americans annually, has no US Food and Drug Administration-approved pharmacotherapy.

OBJECTIVES

To evaluate the immunogenicity, safety, and efficacy of a novel cocaine vaccine to treat cocaine dependence.

DESIGN

A 24-week, phase 2b, randomized, double-blind, placebo-controlled trial with efficacy assessed during weeks 8 to 20 and follow-up to week 24.

SETTING

Cocaine- and opioid-dependent persons recruited from October 2003 to April 2005 from greater New Haven, Connecticut.

PARTICIPANTS

One hundred fifteen methadone-maintained subjects (67% male, 87% white, aged 18-46 years) were randomized to vaccine or placebo, and 94 subjects (82%) completed the trial. Most smoked crack cocaine along with using marijuana (18%), alcohol (10%), and nonprescription opioids (44%).

INTERVENTION

Over 12 weeks, 109 of 115 subjects received 5 vaccinations of placebo or succinylnorcocaine linked to recombinant cholera toxin B-subunit protein. Main Outcome Measure Semiquantitative urinary cocaine metabolite levels measured thrice weekly with a positive cutoff of 300 ng/mL.

RESULTS

The 21 vaccinated subjects (38%) who attained serum IgG anticocaine antibody levels of 43 microg/mL or higher (ie, high IgG level) had significantly more cocaine-free urine samples than those with levels less than 43 microg/mL (ie, low IgG level) and the placebo-receiving subjects during weeks 9 to 16 (45% vs 35% cocaine-free urine samples, respectively). The proportion of subjects having a 50% reduction in cocaine use was significantly greater in the subjects with a high IgG level than in subjects with a low IgG level (53% of subjects vs 23% of subjects, respectively) (P = .048). The most common adverse effects were injection site induration and tenderness. There were no treatment-related serious adverse events, withdrawals, or deaths.

CONCLUSIONS

Attaining high (>or=43 microg/mL) IgG anticocaine antibody levels was associated with significantly reduced cocaine use, but only 38% of the vaccinated subjects attained these IgG levels and they had only 2 months of adequate cocaine blockade. Thus, we need improved vaccines and boosters. Trial Registration clinicaltrials.gov Identifier: NCT00142857.

Therapeutic options and challenges for substances of abuse

Addiction to substances continues to be a significant public health concern in the United States. The following review of current pharmacological treatments discusses a range of substances: nicotine, alcohol, cocaine, and opioids. The goal is to provide an overview of currently available and new pharmacological treatments for substance use disorders, while also addressing the pharmacothera-peutic challenges remaining. The significant advances in pharmacotherapy have had limited utilization, however. For example, naltrexone for alcoholism is infrequently prescribed, buprenorphine for opiates still has relatively few qualified prescribers, and stimulants have no Food and Drug Administration-approved pharmacotherapy. These pharmacotherapies are needed, with the rate of even the relatively uncommon abuse of opiates now rising sharply.

Sustained-release naltrexone: novel treatment for opioid dependence

The devastating costs of opioid abuse and dependence underscore the need for effective treatments for these disorders. At present, several different maintenance medications exist for treating opioid dependence, including methadone, buprenorphine and naltrexone. Of these, naltrexone is the only one that possesses no opioid agonist effects. Instead, naltrexone occupies opioid receptors and prevents or reverses the effects produced by opioid agonists. Despite its clear pharmacologic effectiveness, its clinical effectiveness in treating opioid dependence has been disappointing, primarily due to non-compliance with taking the medication. However, the recent availability of sustained-release formulations of naltrexone has renewed interest in this medication. The present paper describes the development of sustained-release naltrexone formulations and discusses the clinical issues associated with their use in treating opioid dependence.

Depot naltrexone: antagonism of the reinforcing, subjective, and physiological effects of heroin

RATIONALE

Naltrexone is an opioid antagonist that is currently approved as a treatment for opioid and alcohol dependence. Although it is highly effective in completely antagonizing the effects of opioids, medication noncompliance is a difficult obstacle to treatment. Therefore, a sustained-release form of naltrexone may improve treatment outcome.

OBJECTIVE

The present study was designed to evaluate the time course, safety, and effectiveness of a depot formulation of naltrexone (Depotrex).

MATERIALS AND METHODS

Five heroin-dependent individuals participated in an 8-week inpatient study. After a 1-week detoxification period, the effects of a range of heroin doses (0, 6.25, 12.5, and 25 mg, i.v.) were examined. Participants then received 384 mg naltrexone base. The effects of heroin were again evaluated for the next 6 weeks. One dose of heroin was tested per day and the entire dose range was tested each week. Doses were administered in non-systematic order. During a morning sample session, participants received a dose of heroin and $20 and subjective, performance, and physiological effects were measured both before and after drug administration. During an afternoon choice session, participants were given the opportunity to choose the sampled heroin dose and/or amount of money using a modified progressive ratio procedure.

RESULTS

Depot naltrexone antagonized both the reinforcing and subjective effects of heroin for 4-5 weeks. Subjective ratings of withdrawal were reduced after week 2 and throughout the remainder of the study. The effects of heroin on mean trough pupil diameter began to emerge by week 5. There were no clinically significant effects on respiratory or cardiovascular function.

CONCLUSIONS

The present results extend our previous findings by showing that the reinforcing effects of heroin were reduced for 4-5 weeks after administration of 384 mg depot naltrexone.

Injectable, sustained-release naltrexone for the treatment of opioid dependence: a randomized, placebo-controlled trial

CONTEXT

Oral naltrexone can completely antagonize the effects produced by opioid agonists. However, poor compliance with naltrexone has been a major obstacle to the effective treatment of opioid dependence.

OBJECTIVE

To evaluate the safety and efficacy of a sustained-release depot formulation of naltrexone in treating opioid dependence.

DESIGN AND SETTING

Randomized, double-blind, placebo-controlled, 8-week trial conducted at 2 medical centers.

PARTICIPANTS

Sixty heroin-dependent adults.

INTERVENTIONS

Participants were stratified by sex and years of heroin use (> or = 5 vs < 5) and then were randomized to receive placebo or 192 or 384 mg of depot naltrexone. Doses were administered at the beginning of weeks 1 and 5. All participants received twice-weekly relapse prevention therapy, provided observed urine samples, and completed other assessments at each visit.

MAIN OUTCOME MEASURES

Retention in treatment and percentage of opioid-negative urine samples.

RESULTS

Retention in treatment was dose related, with 39%, 60%, and 68% of patients in the placebo, 192 mg of naltrexone, and 384 mg of naltrexone groups, respectively, remaining in treatment at the end of 2 months. Time to dropout had a significant main effect of dose, with mean time to dropout of 27, 36, and 48 days for the placebo, 192 mg of naltrexone, and 384 mg of naltrexone groups, respectively. The percentage of urine samples negative for opioids, methadone, cocaine, benzodiazepines, and amphetamine varied significantly as a function of dose. When the data were recalculated without the assumption that missing urine samples were positive, a main effect of group was not found for any drugs tested except cocaine, where the percentage of cocaine-negative urine samples was lower in the placebo group. Adverse events were minimal and generally mild. This formulation of naltrexone was well tolerated and produced a robust, dose-related increase in treatment retention.

CONCLUSION

These data provide new evidence of the feasibility, efficacy, and tolerability of long-lasting antagonist treatments for opioid dependence.

Attenuation of ethanol self-administration and of conditioned reinstatement of alcohol-seeking behaviour by the antiopioid peptide nociceptin/orphanin FQ in alcohol-preferring rats

RATIONALE

Nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the opioid-like orphan receptor NOP, was shown to reduce home-cage ethanol consumption, ethanol-induced conditioned place preference and stress-induced reinstatement of alcohol-seeking behaviour.

OBJECTIVES

The present study, using genetically selected Marchigian Sardinian alcohol-preferring (msP) rats, was designed to evaluate the effect of this opioid peptide on 10% ethanol and 10% sucrose self-administration, under a fixed-ratio 1 (FR 1) or a progressive-ratio (PR) schedule of reinforcement. Furthermore, using an experimental model of relapse in which rats were trained to lever press for ethanol in the presence of the discriminative stimulus of an orange odour (S(+)) and a 1-s cue light (CS(+)) or for water in the presence of anise odour (S(-)) and 1-s white noise (CS(-)), the effect of N/oFQ on cue-induced reinstatement of extinguished ethanol responding was investigated.

RESULTS

Sub-chronic (6 days) intracerebroventricular (i.c.v.) injection of 0.5 microg or 1.0 microg N/OFQ per rat significantly reduced alcohol self-administration under both the FR 1 and PR schedules of reinforcement. Conversely, i.c.v. administration of 0.5, 1.0 or 4.0 microg of the peptide per rat did not affect sucrose self-administration. In addition, i.c.v. N/OFQ (1.0-2.0 microg per rat) significantly inhibited the reinstatement of extinguished ethanol responding under an S(+)/CS(+) condition, whereas lever pressing under S(-)/CS(-) was not altered.

CONCLUSIONS

The present study demonstrates that the reinforcing effects of ethanol are markedly blunted by activation of the opioidergic N/OFQ receptor system. Moreover, the data provide evidence of the efficacy of N/OFQ to prevent reinstatement of ethanol-seeking behaviour elicited by environmental conditioned stimuli.

Hypericum perforatum CO2 Extract and Opioid Receptor Antagonists Act Synergistically to Reduce Ethanol Intake in Alcohol-Preferring Rats

BACKGROUND

Hypericum perforatum extracts attenuate ethanol intake in alcohol-preferring rats. The opioid receptor antagonists, naloxone and naltrexone, reduce ethanol intake in rats and humans. The combination of different agents that reduce ethanol intake has been proposed as an approach to the pharmacotherapy of alcoholism. This study evaluated the effect on ethanol intake of the combined administration of a CO2 H. perforatum extract and naloxone or naltrexone in genetically selected Marchigian Sardinian alcohol-preferring rats.

METHODS

Ten percent (v/v) ethanol intake was offered 2 hr per day at the beginning of the dark phase of the reverse light-dark cycle. H. perforatum CO2 extract was given intragastrically, 1 hr before access to ethanol. Naloxone or naltrexone was given by intraperitoneal injection 10 min before the extract.

RESULTS

H. perforatum CO2 extract reduced ethanol intake at 31 or 125 mg/kg, but not 7 mg/kg. These doses neither modified food or water intake during access to ethanol, nor reduce 0.2% saccharin intake. Naloxone reduced ethanol and food intake at 3 or 5 mg/kg, but not 1 mg/kg. When naloxone 1 mg/kg was combined with the three doses of H. perforatum CO2 extract, the attenuation of ethanol intake was more pronounced than that observed after the administration of the extract alone. Alcohol intake was also significantly reduced by 7 mg/kg of H. perforatum CO2 extract combined with naloxone 1 mg/kg. The combined treatments never modified the rat's locomotor activity nor the simultaneous intake of food, water or 0.2% saccharin. Naltrexone reduced ethanol intake at 1 and 3 mg/kg, but not at 0.5 mg/kg. When naltrexone 0.5 mg/kg was combined with H. perforatum CO2 extract 7 mg/kg, ethanol intake was markedly reduced.

CONCLUSIONS

These findings provide evidence that H. perforatum CO2 extract and opiate receptor antagonists act synergistically to induce a pronounced and selective reduction of voluntary ethanol consumption in alcohol-preferring rats.

Behavioral family counseling and naltrexone for male opioid-dependent patients

Men (N = 124) entering treatment for opioid dependence who were living with a family member were randomly assigned to one of two 24-week treatments: (a) behavioral family counseling (BFC) plus individual treatment (patients had both individual and family sessions and took naltrexone daily in presence of family member) or (b) individual-based treatment only (IBT; patients were given naltrexone and were asked in counseling sessions about their compliance, but there was no family involvement). BFC patients, compared with their IBT counterparts, ingested more doses of naltrexone, attended more scheduled treatment sessions, had more days abstinent from opioids and other drugs during treatment and during the year after treatment, and had fewer drug-related, legal, and family problems at 1-year follow-up.

Behavioral naltrexone therapy: an integrated treatment for opiate dependence

Treatment of opiate dependence with naltrexone has been limited by poor compliance. Behavioral Naltrexone Therapy (BNT) was developed to promote adherence to naltrexone and lifestyle changes supportive of abstinence, by incorporating components from empirically validated treatments, including Network Therapy with a significant other to monitor medication compliance, the Community Reinforcement Approach, and voucher incentives. An overview is presented of the BNT treatment manual. In an uncontrolled Stage I trial (N = 47), 19% completed the 6-month course of treatment. Retention was especially poor in the subsample of patients who were using methadone at baseline (N = 18; 39% completed 1 month, none completed 6 months), and more encouraging among heroin-dependent patients (N = 29; 65% completed 1 month, 31% completed 6 months). Thus, attrition continues to be a serious problem for naltrexone maintenance, although further efforts to develop interventions such as BNT are warranted.

A comparison of antagonist-precipitated withdrawal under anesthesia to standard inpatient withdrawal as a precursor to maintenance naltrexone treatment in heroin users: outcomes at 6 and 12 months

To compare two methods of heroin withdrawal, 51 heroin users were randomised to undergo a 1 day precipitated withdrawal procedure using naloxone under anaesthetic. About 50 participants were randomised to receive the current standard inpatient withdrawal treatment using clonidine plus symptomatic medication. Following withdrawal, both groups were offered 9 months of naltrexone treatment and supportive counselling. Outcome measures were: commencement of naltrexone, retention in treatment and heroin use at 6 and 12 months. Significantly more of the precipitated withdrawal group completed withdrawal, commenced naltrexone and stayed in treatment for the first 3 months. Overall, there was a significant reduction in both self-reported heroin use and morphine concentration in hair over the 12 month study period, with participants in the precipitated withdrawal group showing significantly lower morphine concentration at 6 months. Being younger and having a lower level of dependence were predictors of abstinence at 6 and 12 months. The advantage of precipitated withdrawal under anesthesia did not persist beyond 3 months with respect to retention in naltrexone treatment or beyond 6 months with respect to heroin use. Long-term follow-up is crucial in assessing the effects of treatment interventions for heroin dependence.

The neurobiology of opioid dependence: implications for treatment

Opioid tolerance, dependence, and addiction are all manifestations of brain changes resulting from chronic opioid abuse. The opioid abuser's struggle for recovery is in great part a struggle to overcome the effects of these changes. Medications such as methadone, LAAM, buprenorphine, and naltrexone act on the same brain structures and processes as addictive opioids, but with protective or normalizing effects. Despite the effectiveness of medications, they must be used in conjunction with appropriate psychosocial treatments.

Depot naltrexone: long-lasting antagonism of the effects of heroin in humans

RATIONALE

Naltrexone, an opioid antagonist, is currently approved as a treatment for heroin dependence. However, naltrexone is generally not well accepted by patients, and medication non-compliance is a difficult obstacle to treatment. A sustained-release form of naltrexone may improve compliance.

OBJECTIVE

The present study was designed to evaluate the time course, safety, and effectiveness of a depot formulation of naltrexone (Depotrex).

METHODS

Twelve heroin-dependent individuals participated in an 8-week inpatient study. After a 1-week detoxification period, six participants received 192 mg naltrexone base and six participants received 384 mg naltrexone base. For safety, the low dose of depot naltrexone was tested before the high dose. The effects of heroin (0, 6.25, 12.5, 18.75, 25 mg, i.v.) were evaluated for the next 6 weeks. One dose of heroin was tested per day on Mondays through Fridays, and the entire dose range was tested each week. Active heroin doses were administered in ascending order during the week, while placebo could be administered on any day. Subjective, performance, and physiological effects were measured both before and after heroin administration. The hypotheses were that depot naltrexone would antagonize the effects of heroin, and that the high dose of depot naltrexone would produce a more effective and longer-lasting antagonism than the low dose.

RESULTS

The low and high doses of depot naltrexone antagonized heroin-induced subjective ratings for 3 and 5 weeks, respectively. Plasma levels of naltrexone remained above 1 ng/ml for approximately 3 and 4 weeks after administration of 192 mg and 384 mg naltrexone. Other than the initial discomfort associated with the injection of depot naltrexone, there were no untoward side-effects.

CONCLUSIONS

These results suggest that this depot formulation of naltrexone provides a safe, effective, long-lasting antagonism of the effects of heroin.

The use of medication for relapse prevention in substance dependence disorders

Substance abuse is a significant problem in itself and can greatly complicate the symptomatology and treatment of comorbid psychiatric disorders. In the article, the authors review literature concerning the use of medication to prevent relapse to substance abuse or decrease substance use. Five different general strategies are employed for this purpose: 1) use of a drug with pharmacological properties similar to the substance of concern (i.e., agonist or substitution therapy); 2) use of a receptor antagonist to block or lessen the effects of the substance of concern; 3) use of a medication that produces a conditioned aversive reaction to the substance of concern; 4) use of a medication to reduce the reinforcing properties of the substance of concern; and 5) use of a substance to increase the metabolism or clearance of the substance of concern from the body. The authors review pharmacological treatments that have been studied for the treatment of dependence on the following types of substances: alcohol, sedative-hypnotics, opioids, stimulants, nicotine, hallucinogens, cannabis, inhalants, anabolic steroids, phencyclidine, and designer drugs. The article ends with a brief discussion of the importance of including psychosocial and behavioral interventions in any substance abuse treatment program.

Improving the quality of substance dependency treatment with pharmacotherapy

This article provides an overview of current pharmacological treatments for alcohol, opioid, cocaine, and nicotine use disorders. Guidelines for a "patient-treatment" matching framework to physicians working with various "substance-abusing" patients are presented, as well as recommendations regarding when to initiate and discontinue pharmacotherapy. Standard and newer pharmacological treatments for substance dependence are reviewed, as well as therapies that may be especially useful when treating the patient with comorbid substance dependency and psychiatric disorders. To maximize the therapeutic benefits of substance dependency treatment, patients should be individually assessed and provided adjunctive medications as clinically indicated. Specific areas for future laboratory and/or clinical research are recommended.

Nociceptin/orphanin FQ and drugs of abuse

Nociceptin/orphanin FQ (NC) binds with high affinity to the opioid receptor-like1 (ORL1) receptor. NC has been reported to block opioid-induced supraspinal analgesia, and it has been proposed that it may represent a functional antiopioid peptide in the control of brain nociceptive processes. The wide distribution of NC and of its receptors in the central nervous system suggests, however, that it may be involved in the control of a variety of biologic functions. Increasing evidence indicates that it may influence the rewarding and reinforcing properties of drugs of abuse. NC has been shown to abolish the rewarding properties of ethanol and morphine in the place conditioning paradigm, to reduce ethanol consumption in alcohol-preferring rats and to inhibit stress-induced alcohol-seeking behavior. These findings suggest that drugs directed at central NC receptors may represent an interesting approach to the treatment of ethanol and opiate abuse.

Substance abuse and emergency psychiatry

Given the high rates of comorbidity, patients commonly present with multiple diagnoses to PESs or crisis services. Clinicians must be well versed in the evaluation, differential diagnosis, and treatment of patients with substance-abuse disorders or other Axis I, II, or III conditions if they are to provide state-of-the-art treatment of patients in need of emergency care.

Pain tolerance in opioid addicts on and off naltrexone pharmacotherapy: a pilot study

Under certain experimental and clinical conditions, opioid antagonists have been demonstrated to have analgesic properties. In this open-label, nonrandomized, within-subject comparison, the effect of chronic treatment with the antagonist, naltrexone, on tolerance for experimental pain was evaluated in a small sample of male opioid addicts (N = 10) receiving naltrexone maintenance. Cold-pressor pain tolerance was measured during (> or = 6 weeks) and after discontinuation (> or = 1 week) of naltrexone treatment. Intra-subject comparison revealed that eight of the ten subjects were more pain tolerant (median + 20 sec) while receiving naltrexone. It is suggested that either midbrain opioid system upregulation in the presence of naltrexone or underlying individual differences in pain tolerance in persons with addictive disease provide potential explanations for these findings.

Efficacy and safety of two new methods of rapid intravenous detoxification in heroin addicts previously treated without success

BACKGROUND

New methods of rapid opiate detoxification, under intravenous sedation, can detoxify heroin-addicted patients in 24 hours. Their clinical application has been limited by the lack of studies establishing both efficacy and safety.

METHOD

In a randomised, controlled study, 300 treatment-refractory, heroin-addicted patients received rapid intravenous detoxification treatment (naloxone infusion, 0.06-0.08 mg/kg, then oral naltrexone 50 mg/day) under either monitored light intravenous sedation or unmonitored deep intravenous sedation.

RESULTS

All patients were successfully detoxified and 93% remained abstinent one month later. Severity of withdrawal, according to the Wang Scale modified by Loimer, was 4.9 (s.d. 3.0) points in the light sedation group and 4.8 (s.d. 2.9) in the deep sedation group (P = 0.26). Two patients (1.3%) in the light sedation group and four (2.6%) in the deep sedation group required tracheal intubation (P = 0.31). There was only one severe complication, a case of nosocomial aspirative pneumonia which improved with antibiotic treatment.

CONCLUSIONS

Successful rapid intravenous detoxification can be achieved using relatively light levels of sedation.

Pharmacotherapy for opioid and cocaine abuse

The need for continued development of medications to address opioid and cocaine addiction is unequivocal. Methadone maintenance, despite its limitations, remains the best-established pharmacologic treatment for opioid dependence. Continued participation in methadone programs is associated with decreased risk of acquiring HIV infection. Clonidine alone or combined with naltrexone may be used for opioid detoxification in the office practice. At the present time, no proven pharmacologic therapy for cocaine addiction exists.

Relapse prevention: an emerging technology for promoting long-term drug abstinence

This article reviews relapse prevention strategies that can be applied after primary drug treatment. To sustain their own recovery, ex-addicts must learn a program of self-management to cope with drug cravings and social pressures to use drugs, become integrated into a new social network, learn to find pleasure in drug-free activities, and find new ways of responding to emotional stress and physical pain. While additional research is needed to identify the very best methods, there is now sufficient evaluation data to argue that practitioners should incorporate this approach as an integral part of their treatment services.

Treatment of heroin addicts using buprenorphine

Thirty-nine opioid-dependent outpatients were treated with the partial agonist buprenorphine at 2 to 6 mg/day for 1 month. Treatment retention was good (72%), and illicit opioid use decreased from 50% overall to 17% for those who remained in treatment. Precipitated withdrawal symptoms were mild and related to dose of buprenorphine. At the end of this month, 28 subjects were abruptly discontinued from buprenorphine and given the antagonist naltrexone. Withdrawal symptoms from buprenorphine were quite mild, and naltrexone was initiated in 20 patients (51% of total or 71% of those 28 completing 30 days on buprenorphine), but only 4 patients (10% overall) were successfully maintained on naltrexone for at least 2 weeks.

Combining pharmacological antagonists and behavioural psychotherapy in treating addictions. Why it is effective but unpopular

Supervised administration of disulfiram is one of the very few treatments that can significantly reduce alcohol consumption, yet it is rarely used, despite being simple and cheap. Disulfiram is not 'aversion therapy', but a technique for facilitating exposure and response prevention, and it fits comfortably into a behavioural, social-learning model of addiction (or dependence) and its treatment. The availability of other effective antagonists, notably to opiates, suggests that an approach that is demonstrably effective in alcohol dependence may be helpful in treating other addictions. The reasons for the unpopularity of this approach appear to be largely ideological.

Opioid antagonist challenges in buprenorphine maintained patients

Following one month of sublingual buprenorphine treatment, 15 patients at either 2 mg (n = 7) or 3 mg (n = 8) were hospitalized and the buprenorphine was abruptly stopped by placebo substitution. On the morning following their last dose of buprenorphine, 10 patients were given 1 mg oral naltrexone and 5 were given 0.5 mg/kg intravenous naloxone in a double blind placebo controlled challenge. The naltrexone challenges produced no increase in opioid withdrawal symptoms, plasma MHPG levels, or blood pressure compared to placebo, while naloxone produced significant symptoms and blood pressure increases compared to placebo challenges.

A Rogerian view of drug abuse: implications for nursing

Drug abuse and the concept of addiction are explored utilizing Martha E. Rogers' conceptual system of unitary human beings, resulting in a novel and thought-provoking view of this health behavior. Following an overview of Rogers' concepts, principles, and theories, the example of the heroin addict is reviewed, conceptualizing the addict as a high-frequency, diverse human energy field integral with a low-frequency, impoverished environmental field. Drug use provides an alternative way to participate in the mutual process. The drug "high" is conceptualized as providing a means to increase one's awareness of the four-dimensional nature of reality. The integral nature of human and environment is illustrated with examples of increasing diversity in each due to human drug use. Addiction is discussed as are other aspects of the environmental field. Finally, nursing interventions at the individual and environmental levels are presented.

Role of opioid antagonists in treating intravenous cocaine abuse

Intravenous cocaine abuse is a major probel in opioid abusers including those treated in methadone maintenance. Studying 138 opioid addicts, we found that speedballing by combining opioid agonists with cocaine may be blocked by opioid antagonists such as naltrexone and by partial antagonists such as buprenorphine. With both these treatments cocaine abuse was five to eight times less than with methadone treatment.

Relationship of marital structure and interactions to opiate abuse relapse

Several aspects of marital functioning were associated with subsequent relapse to opiate abuse in 17 married addicts. The addicts and spouses were evaluated in a task-oriented interview and rated using the Beavers Timberlawn Family Assessment instrument. The global health-pathology ratings on this instrument indicated that most couples had rigid patterns of interacting, rather than a chaotic lack of structure or a flexible, negotiated partnership. Within this range of rigid functioning, higher ratings were associated with longer times drug-free (up to 18 months with a mean of 7 months). On the seven subscales of the Beavers', five were significantly correlated with the time drug-free: effective and clear leadership, closeness between the spouses, a nonhostile mood, empathy, and efficient negotiation and problem solving. The subscales associated with drug abstinence were quite different for a group of seven single ex-addicts participating in the same outpatient program, but living with their parents. For these single ex-addicts three subscales were correlated with the time drug-free: parental reaction to separation strivings, the open expression of thoughts and feelings, and empathy. This difference in the subscales associated with abstinence for married versus single addicts suggested some specificity in the characteristics of family structure and interaction that may be related to drug abstinence.

Clonidine and naltrexone in the outpatient treatment of heroin withdrawal

Clonidine hydrochloride (an alpha-2 adrenergic agonist) and naltrexone hydrochloride (an opioid antagonist), given in combination, provided a safe and effective treatment of abrupt opioid withdrawal over 5 days in an outpatient/day setting. Before starting the clonidine, a naloxone challenge test was used to verify and quantify opioid dependence, and the naloxone challenge test score was then used to determine initial medication doses. Initial naloxone challenge test scores predicted subsequent patient discomfort during the 5-day clonidine-naltrexone protocol. Twelve of 14 (86%) heroin users successfully withdrew from opioids and simultaneously initiated naltrexone maintenance.

A preliminary study of beta endorphin during chronic naltrexone maintenance treatment in ex-opiate addicts

Because opioid antagonists acutely produce rises in serum beta endorphin, we studied beta endorphin levels in 21 former opiate addicts chronically taking naltrexone. The mean AM (19.5 pg/ml) beta endorphin level was higher than the AM mean for 39 normals under 40 years old (12.1 pg/ml) (t = 3.2, p less than 0.001); the mean PM level for the naltrexone treated patients was 13.6 pg/ml. Four patients had beta endorphin levels more than 2 S.D. above the mean for the normals (greater than 26.4 pg/ml), and six others had relatively elevated PM levels. Thus, 47% (10/21) had abnormal patterns of beta endorphin levels. We had previously reported abnormally high cortisol levels in these patients, and AM cortisol correlated with AM beta endorphin levels (r = 0.7, p less than 0.001). We concluded that sustained beta endorphin elevations may occur during chronic naltrexone treatment.

Nontolerance to the opioid antagonism of naltrexone

Controlled opiate challenges of naltrexone-pretreated human subjects have established that naltrexone is an effective opioid antagonist. However, these challenges have been conducted after relatively acute dosing with naltrexone, and tolerance to this antagonism after chronic treatment is possible. We therefore administered morphine challenges in a double-blind, placebo-controlled design to nine ex-addicts who had been taking naltrexone for a mean of 9.4 months. None of the ex-addicts experienced euphoria; instead, most of these blockaded ex-addicts had a dysphoric histaminelike response to the intravenous morphine. The only physiological change was a slight increase in heart rate. We conclude that tolerance does not develop to the opioid antagonist properties of naltrexone up to as long as 21 months of treatment.

Perceived marital and family environment of opiate addicts

Addicts have described their family environment as providing inadequate modeling of social and role skills, while having high expectations for achievement. These self-reports have not been compared to either the reports of other family members or observer ratings of addict families. Observer ratings are important because addicts have also described their families as having significantly less conflict than normative families. We administered the Moos Family Environment Scale (FES) to 73 addicts and found that our addicts' scores supported the previous descriptions of addicts' perceived family environment. Addicts' perceived family environment differed from normative samples. They perceived their family as providing little preparation for social roles, while expecting high achievement. When addicts' wives or mothers completed the FES (n = 27), they disagreed with the addicts' perceptions of having high expectations for achievement in the marriage or family. Relative to their mothers and wives, the addicts seemed to be insensitive to the lack of effective organization and limit setting in either their family of origin or marriage. However, the mothers and wives agreed with the addicts in reporting low levels of conflict, but behavioral ratings of the married addicts and their wives (n = 16) showed a poor correlation between the observed behavior and the couples' perceptions. Furthermore, the level of conflict appeared to be above rather than below normative samples. Thus, addicts' perceptions of their family environment demonstrated significant discrepancies from the perceptions of their wives and mothers and from ratings of their marital behavior.