Naloxone treatment in opioid addiction: the risks and benefits

Naloxone is a non-selective, short-acting opioid receptor antagonist that has a long clinical history of successful use and is presently considered a safe drug over a wide dose range (up to 10 mg). In opioid-dependent patients, naloxone is used in the treatment of opioid-overdose-induced respiratory depression, in (ultra)rapid detoxification and in combination with buprenorphine for maintenance therapy (to prevent intravenous abuse). Risks related to naloxone use in opioid-dependent patients are: i) the induction of an acute withdrawal syndrome (the occurrence of vomiting and aspiration is potentially life threatening); ii) the effect of naloxone may wear off prematurely when used for treatment of opioid-induced respiratory depression; and iii) in patients treated for severe pain with an opioid, high-dose naloxone and/or rapidly infused naloxone may cause catecholamine release and consequently pulmonary edema and cardiac arrhythmias. These risks warrant the cautious use of naloxone and adequate monitoring of the cardiorespiratory status of the patient after naloxone administration where indicated.

Naltrexone in patients with bipolar disorder and alcohol dependence

Bipolar disorder is associated with very high rates of substance abuse. However, few clinical trials are reported in this population. Naltrexone is effective for alcohol dependence, but its safety and efficacy are not established in patients with bipolar disorder and alcohol dependence. A 16-week, open-label, add-on pilot study of naltrexone was conducted in 34 outpatients with bipolar disorder and alcohol dependence. Assessments included the 17-item Hamilton Rating Scale for Depression (HRSD-17), Young Mania Rating Scale (YMRS), Brief Psychiatric Rating Scale (BPRS), and an alcohol craving scale. Alcohol use was quantified. Significant improvement was observed in the HRSD-17 and YMRS, and days of alcohol use and craving decreased significantly. Naltrexone was well tolerated. Controlled trials are warranted.

The adoption of medications in substance abuse treatment: associations with organizational characteristics and technology clusters

Despite growing interest in closing the "research to practice gap", there are few data on the availability of medications in American substance abuse treatment settings. Recent research suggests that organizational characteristics may be associated with medication availability. It is unclear if the availability of medications can be conceptualized in terms of "technology clusters", where the availability of a medication is positively associated with the likelihood that other medications are also offered. Using data from 403 privately funded and 363 publicly funded specialty substance abuse treatment centers in the US, this research models the availability of agonist medications, naltrexone, disulfiram, and SSRIs. Bivariate logistic regression models indicated considerable variation in adoption across publicly funded non-profit, government-owned, privately funded non-profit, and for-profit treatment centers. Some of these differences were attenuated by organizational characteristics, such as accreditation, the presence of staff physicians, and the availability of detoxification services. There was some evidence that naltrexone, disulfiram, and SSRIs represent a group of less intensely regulated medications that is distinct from more intensely regulated medications. These types of medications were associated with somewhat different correlates. Future research should continue to investigate the similarities and differences in the predictors of medication availability across national contexts.

Cost-effectiveness of prize-based incentives for stimulant abusers in outpatient psychosocial treatment programs

OBJECTIVE

To evaluate the cost-effectiveness of a prize-based intervention as an addition to usual care for stimulant abusers.

METHODS

This cost-effectiveness analysis is based on a randomized clinical trial implemented within the National Drug Abuse Treatment Clinical Trials Network. The trial was conducted at eight community-based outpatient psychosocial drug abuse treatment clinics. Four hundred and fifteen stimulant abusers were assigned to usual care (N=206) or usual care plus abstinence-based incentives (N=209) for 12 weeks. Participants randomized to the incentive condition earned the chance to draw for prizes for submitting substance negative samples; the number of draws earned increased with continuous abstinence time. Incremental cost-effectiveness ratios were estimated to compare prize-based incentives relative to usual care. The primary patient outcome was longest duration of confirmed stimulant abstinence (LDA). Unit costs were obtained via surveys administered at the eight participating clinics. Resource utilizations and patient outcomes were obtained from the clinical trial. Acceptability curves are presented to illustrate the uncertainty due to the sample and to provide policy relevant information.

RESULTS

The incremental cost to lengthen the LDA by 1 week was 258 US dollars (95% confidence interval, 191-401 US dollars). Sensitivity analyses on several key parameters show that this value ranges from 163 to 269 US dollars.

CONCLUSIONS

Compared with the usual care group, the incentive group had significantly longer LDAs and significantly higher costs.

A comparison of oral and implant naltrexone outcomes at 12 months

Naltrexone's current use has been limited by compliance. Subcutaneous implants would seem to offer a solution to this problem and improve long-term outcomes. The aim of the present study was to compare groups of patients who had received oral naltrexone or a naltrexone implant after detoxification and to follow their progress. Forty-one patients received an implant, and 42 patients received oral naltrexone. They were surveyed at one, three, six, and 12 months after detoxification. Their designated support person was also contacted to confirm the self-reports of the participants. Patients were compared on gender, age, and length of time since detoxification. Implant patients showed much higher abstinence rates, while those in both groups who were abstinent showed greater compliance to naltrexone (time spent in treatment) and attended more counseling sessions. Although the participants were not randomly allocated to each treatment condition, the preliminary evidence indicates that implants can improve compliance rates and outcomes.

A comparison of rapid (opioid) detoxification with clonidine-assisted detoxification for heroin-dependent persons

This study compares two methods of detoxification available to heroin users in Western Australia: clonidine-assisted detoxification (CD) or clonidine-naloxone precipitated withdrawal under sedation (rapid opioid detoxification [ROD]). Oral naltrexone was made available to all participants following detoxification. Eighty heroin-dependent persons were randomly assigned to either ROD or CD. Most undertaking ROD commenced and completed this treatment. Less than one-third undertaking CD completed this treatment. There was no significant difference in those treated by CD or ROD in subjective assessment of degree or duration of pain, severity of withdrawal and craving, nor was there an increase in the withdrawal sequelae after treatment. Induction of oral naltrexone following ROD was greater, but oral naltrexone compliance levels and abstinence from heroin four weeks following detoxification were similar between ROD and CD groups. The level of patient satisfaction between the two treatments was also similar. The authors discuss why ROD is considered more effective than CD.

Evaluation of cognitive functioning in 101 patients before opiate detoxification: implications in setting up therapeutic strategies

Many studies have brought to light the facts that repeated use of drugs significantly influences one's cognitive functions, and that cognitive problems could interfere directly with one's capacity to participate in a rehabilitation program. In this research, we used the Global Deterioration Scale (GDS) to assess the cognitive status of 101 hospitalized patients in an opiate detoxification program. The results reveal that a majority of the tested patients present cognitive abnormalities to varying degrees of severity. Furthermore, these cognitive deficits are correlated with four Addiction Severity Index (ASI) scales (medical, alcohol use, drug use, and psychiatry, respectively). Considering the results, because cognition is a major issue in detoxification and rehabilitation programs, simple cognitive screening (as with the GDS) coupled with a particular interest in some aspects of a patient's anamnesis could lead to better management of opiate-dependent patients.

A randomized trial of one-day vs. three-day buprenorphine inpatient detoxification protocols for heroin dependence

Detoxification from opioids remains an important first step in the treatment of many patients with opioid dependence. Several pharmacologic regimens have been used for opioid detoxification. In the United States, the partial mu-opioid agonist, buprenorphine (BUP) is the most recently approved pharmacotherapy for opioid detoxification and replacement. The literature in recent years has described detoxification protocols using a single high dose of BUP and a three-day BUP regimen. In many settings, such as drug-free programs, a single-dose detoxification protocol would be of significant benefit. There have been no prior studies comparing one-day and three-day BUP-assisted opioid withdrawal. In this pilot study, we conducted an open-label, randomized trial of one-day vs. three-day BUP/naloxone sublingual tablet-assisted opioid withdrawal. Twenty patients from a therapeutic community treatment program were randomly assigned to receive either 32 mg sublingual BUP over one hour (one-day group), or 32 mg sublingual BUP over three days (three-day group). Nine of 10 subjects (90 percent) in each group completed seven days in the detoxification protocol. There was no statistically significant difference between the two groups in all other outcome variables, including retention in the treatment program, intensity of withdrawal signs and symptoms, amounts of adjunct medications used, and ability to produce opiate-free urine. This study further validates the feasibility of the single high dose of BUP as a rapid detoxification method.

Effects of lofexidine on stress-induced and cue-induced opioid craving and opioid abstinence rates: preliminary findings

OBJECTIVE

A preliminary study examined whether lofexidine decreases stress-induced and cue-induced opioid craving and improves opioid abstinence in naltrexone-treated opioid-dependent individuals.

MATERIALS AND METHODS

Eighteen opioid-dependent patients were stabilized for 4 weeks with naltrexone (50 mg daily) and lofexidine (2.4 mg bid) before entering a 4-week randomized, double-blind placebo-controlled discontinuation study where one group continued on lofexidine for an additional 4 weeks, while the second was tapered to placebo (Lofexidine-naltrexone vs Placebo-naltrexone). Ten patients also participated in guided imagery exposure to stress, drug cue, and neutral scenarios in a single laboratory session.

RESULTS

Lofexidine-naltrexone patients had higher opioid abstinence rates and improved relapse outcomes as compared to the Placebo-naltrexone group. Furthermore, Lofexidine-naltrexone patients had significantly lower heart rates and an attenuated stress and drug cue-induced opioid craving response in the laboratory as compared to the Placebo-naltrexone group.

CONCLUSIONS

Although preliminary, these findings are the first to document lofexidine's potential in addressing stress-related opioid craving and relapse outcomes in humans. The results also suggest that combination therapies that target both drug-related reinforcement (naltrexone) and stress- and cue-related aspects of drug seeking could be beneficial in addiction relapse prevention. Further development of lofexidine to address stress-related opioid craving and relapse is warranted.

Building Better Cognitive-Behavioral Therapy: Is Broad-Spectrum Treatment More Effective Than Motivational-Enhancement Therapy for Alcohol-Dependent Patients Treated With Naltrexone?*

OBJECTIVE

The current study investigated the treatment effectiveness, during treatment, of a second-generation cognitive-behavioral therapy for alcoholism--broad-spectrum treatment (BST)--compared with motivational-enhancement therapy (MET), when both were offered in conjunction with a therapeutic dose of naltrexone (Revia).

METHOD

One hundred forty-nine alcohol-dependent patients completed a 3-month randomized, controlled trial of BST and naltrexone versus MET and naltrexone.

RESULTS

Patients receiving BST had a significantly higher percentage of days abstinent than patients receiving MET. The superior effect of BST is particularly strong in interaction with support for drinking, suggesting that the advantage of BST is worth the additional cost for patients whose psychosocial networks are supportive of continued drinking. This effect remains significant when controlling for pretreatment percentage of days abstinent.

CONCLUSIONS

In aggregate, these findings suggest that it is either the combination of naltrexone and BST or the unique properties of BST that account for BST's superiority to MET and naltrexone. The results of this initial phase of the trial suggest that a second-generation cognitive-behavioral therapy such as BST may have a meaningful clinical advantage over brief interventions such as MET, at least when combined with naltrexone.

Buprenorphine-associated gastroparesis during in-patient heroin detoxification

BACKGROUND

Buprenorphine is a partial mu receptor agonist used in opiate detoxification. It has been shown to cause delayed gastric emptying in healthy volunteers.

CASE DESCRIPTION

We describe a case of clinically severe gastroparesis (delayed gastric emptying due to impaired contraction of the stomach) whose onset coincided with the commencement of buprenorphine-assisted detoxification.

CONCLUSION

We review the literature on gastric effects of buprenorphine in healthy volunteers, providing proof of the concept that this was the most probable cause of this patient's gastroparesis.

Treating opioid addiction with buprenorphine-naloxone in community-based primary care settings

PURPOSE

Office-based treatment of opioid addiction with a combination of buprenorphine and naloxone was approved in 2002. Efficacy of this treatment in non-research clinical settings has not been studied. We examined the efficacy and practicality of buprenorphine-naloxone treatment in primary care settings.

METHODS

We studied a cohort of 99 consecutive patients enrolled in buprenorphine-naloxone treatment for opioid dependence at 2 urban primary care practices: a hospital-based primary care clinic, and a primary care practice in a free-standing neighborhood health center. The primary outcome measure was sobriety at 6 months as judged by the treating physician based on periodic urine drug tests, as well as frequent physical examinations and questioning of the patients about substance use.

RESULTS

Fifty-four percent of patients were sober at 6 months. There was no significant correlation between sobriety and site of care, drug of choice, neighborhood poverty level, or dose of buprenorphine-naloxone. Sobriety was correlated with private insurance status, older age, length of treatment, and attending self-help meetings.

CONCLUSIONS

Opioid-addicted patients can be safely and effectively treated in non-research primary care settings with limited on-site resources. Our findings suggest that greater numbers of patients should have access to buprenorphine-naloxone treatment in nonspecialized settings.

Plasma met-enkephalin, beta-endorphin and leu-enkephalin levels in human hepatic encephalopathy

To address the role of the opioid system in the pathogenesis of hepatic encephalopathy (HE) we measured plasma met-enkephalin, beta-endorphin and leu-enkephalin in patients with different grades of HE compared to control subjects and patients with cirrhosis. Plasma met-enkephalin levels were significantly higher in patients with cirrhosis and all grades of HE than controls. Plasma beta-endorphin levels were similar in the 3 groups. Plasma leu-enkephalin levels were significantly higher in HE grades II, III and IV than in controls, patients with cirrhosis and HE grade I patients. Our results support data on the involvement of met-enkephalin and leu-enkephalin in the pathogenesis of HE and provide a rationale for the use of opioid receptor antagonists in the treatment of HE.

The relationship between temporal discounting and the prisoner's dilemma game in intranasal abusers of prescription opioids

Previous research on college students has found that cooperation in iterated prisoner's dilemma game is correlated with preference for delayed rewards in studies of temporal discounting. The present study attempted to replicate this finding in a drug-dependent population. Thirty-one individuals who intranasally abuse prescription opioids participated in temporal discounting and iterated prisoner's dilemma game procedures during intake for a treatment study. Rate of temporal discounting was determined for each participant at two hypothetical reward magnitudes, as well as proportion of cooperation in a 60-trial iterated prisoner's dilemma game versus a tit-for-tat strategy. Cooperation in the prisoner's dilemma game and temporal discounting rates were significantly correlated in the predicted direction: individuals who preferred delayed rewards in the temporal discounting task were more likely to cooperate in the prisoner's dilemma game.

Outpatient treatment engagement and abstinence rates following inpatient opioid detoxification

Many patients with chronic opioid dependence are referred to drug-free outpatient treatment following inpatient detoxification even though successful outpatient treatment engagement and abstinence from opioids occur only in a minority of cases. This retrospective cohort analysis of medical records documents the post-discharge outcome in a treatment setting that maximizes the support during transition to abstinence-oriented outpatient care, with comprehensive social, medical and mental health services, including the availability of naltrexone. Participants were male veterans (N = 112) admitted at an urban VA medical center. Most patients (78%) successfully completed acute detoxification, 49% initiated naltrexone, and 76% accepted a VA aftercare plan. At 90-day follow-up, only 22% remained in aftercare, and < 3% had toxicology-verified abstinence from opioids. At one-year follow-up, 1 out of 5 had been readmitted for detoxification and 4.5% had died. Most patients successfully detoxified from opioids, but very few remained engaged and stabilized in abstinence-oriented outpatient treatment.

Experiences of a national sample of qualified addiction specialists who have and have not prescribed buprenorphine for opioid dependence

The limited availability of medication-assisted treatment has created a treatment gap leaving many opioid dependent individuals without access to appropriate treatment. Survey data from a national random sample of 545 addictions physicians with waivers to provide buprenorphine treatment under The Drug Addiction Treatment Act of 2000 are presented. During the first year, an estimated 63,204 opioid dependent patients were treated with buprenorphine; many were dependent on prescription opioids and were new to drug treatment. Prescribing physicians reported high treatment effectiveness and patient satisfaction, with minimal adverse reactions or evidence of diversion. However, many waivered physicians had not provided buprenorphine treatment. Prescribers identified challenges such as induction logistics, recordkeeping requirements, the 30-patient limit, DEA involvement, and limited patient compliance. Buprenorphine treatment could potentially reduce the treatment gap by providing safe and effective treatment for opioid dependence and by attracting patients who do not typically seek care at opioid treatment programs.

Buprenorphine assay and plasma concentration monitoring in HIV-infected substance users

The availability of buprenorphine (BUP) provides an alternative approach to the treatment of opioid addiction with methadone, an agent that has many drug-drug interactions when combined with antiretroviral therapy (ART). However, due to limited long-term pharmacokinetic studies in HIV-infected patients, the clinical use of BUP, a CYP450-3A4 substrate, will require that studies be conducted to examine safety, tolerability and pharmacokinetics when these drugs are taken for chronic treatment. One clinical approach could include plasma concentration monitoring to avoid under- or overdosing BUP secondary to drug interactions with ART. The measurement of BUP and its active metabolite, norbuprenorphine (NBUP) facilitates the addition of BUP to ART in an attempt to avoid drug toxicity as described in a recent report by Bruce et al. Therefore, our objective was to validate a BUP assay and integrate its application into an ongoing antiretroviral (ARV) plasma concentration monitoring program. A chromatographic method for monitoring BUP and its active metabolite, NBUP was investigated. An assay was developed that would facilitate BUP and ARV measurement from a single 3 mL blood sample (0.75 mL plasma required) in conjunction with a previously validated multiple ARV HPLC method. The method measures BUP and NBUP over the range from 0.25 to 50 ng/mL with mass spectrometry detection. Inter- and intra-assay variation was <or=11%, across the concentration range. The method quantitates BUP and NBUP plasma concentrations within the range of expected values from current BUP dosing guidelines. Use of this combined BUP and ARV plasma concentration monitoring approach for a representative patient receiving BUP, atazanavir and efavirenz demonstrated its clinical application.

Onset of symptoms after methadone overdose

BACKGROUND

Methadone ingestion may cause delayed coma and require naloxone infusion. Few studies exist regarding the time development of symptoms following methadone overdose in adults.

METHODS

After a brief training period, reviewers who were blinded to the purpose of the study completed a standardized data collection sheet. Two consecutive years of poison center patient encounters were reviewed. Age, outcomes, coingestions, vital signs, clinical manifestations, hospital admissions, and mortality were abstracted. Data were analyzed using descriptive statistics. The first reviewer was designated to extract the data. The second reviewer conducted a review of 20% of all the charts for a kappa value to be calculated.

RESULTS

In total, 44 cases of isolated methadone overdose in patients older than 18 years were identified. A mean age of 32.5 (18-58) years and a mean presumed ingestion of 106 mg of methadone was calculated. Of the 44 patients, 32 received naloxone for symptoms consistent with opiate toxicity. All symptoms occurred within 9 hours of methadone ingestion, with a mean symptom onset of 3.2 hours. All patients had resolution of symptoms within 24 hours. No deaths were recorded. The kappa score for interreviewer reliability was 0.69, with a 95% confidence interval of 0.58 to 0.73.

LIMITATIONS

This was a retrospective study that was limited by patient history.

CONCLUSION

Acute methadone toxicity typically results in symptoms within 9 hours of ingestion.

Prescribing naloxone to actively injecting heroin users: a program to reduce heroin overdose deaths

Heroin overdose deaths have increased alarmingly in Chicago over the past decade. Naloxone, an opioid antagonist with no abuse potential, has been used to reverse opiate overdose in emergency medical settings for decades. We describe here a program to educate opiate users in the prevention of opiate overdose and its reversal with intramuscular naloxone. Participant education and naloxone prescription are accomplished within a large comprehensive harm reduction program network. Since institution of the program in January 2001, more than 3,500 10 ml (0.4 mg/ml) vials of naloxone have been prescribed and 319 reports of peer reversals received. The Medical Examiner of Cook County reported a steady increase in heroin overdose deaths since 1991, with a four-fold increase between 1996 and 2000. This trend reversed in 2001, with a 20% decrease in 2001 and 10% decreases in 2002 and 2003.

Preclinical and clinical pharmacology of alcohol dependence

In recent years, advances in neuroscience led to the development of new medications to treat alcohol dependence and especially to prevent alcohol relapse after detoxification. Whereas the earliest medications against alcohol dependence were fortuitously discovered, recently developed drugs are increasingly based on alcohol's neurobiological mechanisms of action. This review discusses the most recent developments in alcohol pharmacotherapy and emphasizes the neurobiological basis of anti-alcohol medications. There are currently three approved drugs for the treatment of alcohol dependence with quite different mechanisms of action. Disulfiram is an inhibitor of the enzyme aldehyde dehydrogenase and acts as an alcohol-deterrent drug. Naltrexone, an opiate antagonist, reduces alcohol craving and relapse in heavy drinking, probably via a modulation of the mesolimbic dopamine activity. Finally, acamprosate helps maintaining alcohol abstinence, probably through a normalization of the chronic alcohol-induced hyperglutamatergic state. In addition to these approved medications, many other drugs have been suggested for preventing alcohol consumption on the basis of preclinical studies. Some of these drugs remain promising, whereas others have produced disappointing results in preliminary clinical studies. These new drugs in the field of alcohol pharmacotherapy are also discussed, together with their mechanisms of action.