Employment-based reinforcement of adherence to an FDA approved extended release formulation of naltrexone in opioid-dependent adults: a randomized controlled trial

Employment-based reinforcement of adherence to oral naltrexone treatment in unemployed injection drug users

Oral naltrexone has high potential for use as a relapse prevention pharmacotherapy for opiate dependence yet suffers from notoriously poor adherence. This study evaluated whether entry to a therapeutic workplace could reinforce adherence with oral naltrexone. Opiate-dependent and cocaine-using injection drug users were detoxified, inducted onto oral naltrexone, and randomly assigned to a contingency (n = 35) or prescription (n = 32) group for a 26-week period. Contingency participants were required to ingest naltrexone under staff observation to gain access to the therapeutic workplace. Prescription participants received a take-home supply of naltrexone and could access the workplace independent of naltrexone ingestion. Primary outcome measures were percent of urine samples positive for naltrexone at 30-day assessments and negative for opiates and cocaine at 30-day assessments. Contingency participants provided significantly more urine samples that were positive for naltrexone compared with prescription participants (72% vs. 21%, p < .01); however, no effect of experimental group was observed on percent opiate-negative (71% vs. 60%, p = .19.) or cocaine-negative (56% vs. 53%, p = .82) samples in the contingency and prescription groups, respectively. Opiate-positive samples were significantly more likely to occur in conjunction with cocaine (p < .001) and when not protected by naltrexone (p < .02), independent of experimental group. Overall, these results show that contingent access to a therapeutic workplace significantly promoted adherence to oral naltrexone, and that the majority of opiate use occurred in conjunction with cocaine use, suggesting that untreated cocaine use may limit the effectiveness of oral naltrexone in promoting opiate abstinence.

Pharmacological therapies for maintenance treatments of opium dependence

BACKGROUND

Pharmacologic therapies for maintenance treatment of heroin dependence have been used and studied widely. Systematic reviews have demonstrated the effectiveness of such therapies. Opium dependence is associated with less problems and impairments and is less likely to be used by injecting, with consequent reductions in risk of overdose and blood-borne diseases. Although it is a common substance use disorder in many countries, a systematic review of the literature is lacking on the maintenance treatment for opium dependence.

OBJECTIVES

To evaluate the effectiveness and safety of various pharmacological therapies on maintenance of opium dependence (alone or in combination with psychosocial interventions) compared to no intervention, detoxification, different doses of the same intervention, other pharmacologic interventions and any psychosocial interventions.

SEARCH METHODS

We searched the following sources up to February 2012: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, regional databases (IMEMR and ASCI), national databases (Iranmedex and Iranpsych), main electronic sources of ongoing trials and reference lists of all relevant papers. Also, we contacted known investigators from some Asian countries to obtain details about unpublished trials.

SELECTION CRITERIA

Randomised controlled clinical trials (RCTs) comparing any maintenance pharmacologic intervention versus no intervention, other pharmacologic or non-pharmacologic intervention for opium dependence.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the risks of biases and extracted data, independently.

MAIN RESULTS

Three RCTs recruiting 870 opium dependents were included. The studies made different comparisons so it was not possible to pool data. Only retention rate was assessed by the studies. Two studies compared different doses of buprenorphine: in one study, 4 mg/day of buprenorphine was compared with doses of 2 mg/day and 1 mg/day and in another study, 8 mg/day of buprenorphine was compared with doses of 3 mg/day and 1 mg/day. Comparisons showed a statistically significant difference between groups; higher doses of buprenorphine increased the probability of retention in treatment. The studies had high risks of biases. In the third study, after a process of detoxification, baclofen (60 mg/day) was compared with placebo for maintenance treatment. The difference in retention rate between groups was high, but it was not statistically significant.

AUTHORS' CONCLUSIONS

It is not possible to conclude about the use of any kind of pharmacologic therapies for maintenance treatment of opium dependence.

Perhaps More Consideration of Pavlovian-Operant Interaction May Improve the Clinical Efficacy of Behaviorally Based Drug Treatment Programs

Drug abuse remains costly. Drug-related cues can evoke cue-reactivity and craving, contributing to relapse. The Pavlovian extinction-based cue-exposure therapy (CET) has not been very successful in treating drug abuse. A functional operant analysis of complex rituals involved in CET is outlined and reinterpreted as an operant heterogeneous chain maintained by observing responses, conditioned reinforcers, and discriminative stimuli. It is further noted that operant functions are not predicated on Pavlovian processes but can be influenced by them in contributing to relapse; several empirical studies from the animal and human literature highlight this view. Cue-reactivity evoked by Pavlovian processes is conceptualized as an operant establishing/motivating operation. CET may be more effective in incorporating an operant-based approach that takes into account the complexity of Pavlovian-operant interaction. Extinction of the operant chain coupled with the shaping of alternative behaviors is proposed as an integrated therapy. It is proposed that operant-based drug abuse treatments (contingency management, voucher programs, and the therapeutic work environment) might consider incorporating cue-reactivity, as establishing/motivating operations, to increase long-term success-a hybrid approach based on Pavlovian-operant interaction.

Maintenance of reinforcement to address the chronic nature of drug addiction

BACKGROUND

Drug addiction can be a chronic problem. Abstinence reinforcement can initiate drug abstinence, but as with other treatments many patients relapse after the intervention ends. Abstinence reinforcement can be maintained to promote long-term drug abstinence, but practical means of implementing long-term abstinence reinforcement are needed.

METHODS

We reviewed 8 clinical trials conducted in Baltimore, MD from 1996 through 2010 that evaluated the therapeutic workplace as a vehicle for maintaining reinforcement for the treatment of drug addiction. The therapeutic workplace uses employment-based reinforcement in which employees must provide objective evidence of drug abstinence or medication adherence to work and earn wages.

RESULTS

Employment-based reinforcement can initiate (3 of 4 studies) and maintain (2 studies) cocaine abstinence in methadone patients, although relapse can occur even after long-term exposure to abstinence reinforcement (1 study). Employment-based reinforcement can also promote abstinence from alcohol in homeless alcohol dependent adults (1 study), and maintain adherence to extended-release naltrexone in opioid dependent adults (2 studies).

CONCLUSION

Treatments should seek to promote life-long effects in patients. Therapeutic reinforcement may need to be maintained indefinitely to prevent relapse. Workplaces could be effective vehicles for the maintenance of therapeutic reinforcement contingencies for drug abstinence and adherence to addiction medications.

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.

Naltrexone extended-release injection: an option for the management of opioid abuse

The United States Food and Drug Administration (FDA) approved naltrexone, a synthetic competitive antagonist at opioid receptors, in oral form in 1984 for use in the management of opioid abuse and addiction. Because naltrexone and its major metabolite, 6-β-naltrexone, are both competitive antagonists at opioid receptors - and thereby inhibit opioid agonist-induced effects including those desired by abusers - it was hypothesized that once maintained on naltrex-one, opioid-induced desirable effects would be diminished to the point that relapse to illicit use would decline because it was no longer rewarding. However, good medication compliance is a requisite for such a strategy to be effective and a systematic review of oral naltrexone concluded that this method of treatment was not superior for any outcomes measured (ie, retention, abstinence, or side effects) to placebo, psychotherapy, benzodiazepines, or buprenorphine treatment. In addition, the retention rate on oral naltrexone was very low (less than 30%). Recently, the FDA approved an extended-release formulation (intramuscular depot injection) of naltrexone for prevention of relapse to opioid dependence following opioid detoxification and to be used along with counseling and social support. Since it needs to be administered only monthly, as opposed to the daily administration required for the oral formulation, naltrexone injection has the potential for increasing adherence and retention rates. Concerns include liver damage at high doses (oral formulation) and possible opioid overdose if an attempt is made to surmount receptor antagonism by taking higher doses of an opioid agonist or if opioid receptors become "sensitized" under long-term antagonism. The focus of the present review is the current information regarding the safety and efficacy of naltrexone extended-release therapy.