Oral naltrexone maintenance treatment for opioid dependence
Opioid dependence is considered to be a lifelong, chronic relapsing disorder. Substantial therapeutic efforts are needed to keep people drug free. Methadone treatment plays a vital role in detoxification or maintenance programs but some individuals who are on methadone continue to use illicit drugs, commit crime and engage in behaviours that promote the spread of communicable diseases. Naltrexone is a long acting opioid antagonist that does not produce euphoria and is not addicting. It is used in accidental heroin overdose and for the treatment of people who have opioid dependence. Naltrexone is particularly suitable to prevent a relapse to opioid use after heroin detoxification for those for whom failure to comply with treatment has major consequences, for example health professionals, business executives and individuals under legal supervision. Medication compliance and retention rates with naltrexone treatment are however low. In this review of the medical literature oral naltrexone, with or without psychotherapy, was no better than placebo or no pharmacological treatments with regard to retention in treatment, use of the primary substance of abuse or side effects. The only outcome that was clearly in favour of naltrexone was a reduction of re incarcerations by about a half but these results were from only two studies. In single studies naltrexone was not superior to benzodiazepines or buprenorphine for retention, abstinence or side effects. The review authors identified a total of 13 randomised controlled studies that involved 1158 opioid addicts treated as outpatients following detoxification. Less than a third of participants were retained in treatment over the duration of the included studies. The mean duration was six months (range one to 10 months). None of included studies considered deaths from fatal overdoses in people treated with naltrexone.
Available from: José Martínez-Raga
- "Two pharmacotherapies were considered in the analysis: methadone and B/N combination. Although the opioid antagonist naltrexone was also available as a treatment option for relapse prevention for heroin dependent subjects, this medication was excluded from the analysis due its limited acceptance among both patients and clinicians  and the lack of sufficient evidence supporting its use as a maintenance therapy for opioid dependence . "
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ABSTRACT: Opioid addiction is a worldwide problem. Agonist opioid treatment (AOT) is the most widespread and frequent pharmacotherapeutic approach. Methadone has been the most widely used AOT, but buprenorphine, a partial μ-opiod agonist and a κ-opiod antagonist, is fast gaining acceptance. The objective was to assess the budgetary impact in Spain of the introduction of buprenorphine-naloxone (B/N) combination.
A budgetary impact model was developed to estimate healthcare costs of the addition of B/N combination to the therapeutic arsenal for treating opioid dependent patients, during a 3-year period under the National Health System perspective. Inputs for the model were obtained from the specialized scientific literature. Detailed information concerning resource consumption (drug cost, logistics, dispensing, medical, psychiatry and pharmacy supervision, counselling and laboratory test) was obtained from a local expert panel. Costs are expressed in euros (€, 2010).
The number of patients estimated to be prescribed B/N combination was 2,334; 2,993 and 3,589 in the first, second and third year respectively. Total budget is €85,766,129; €79,855,471 and €79,137,502 in the first, second and third year for the scenario without B/N combination. With B/N combination the total budget would be €86,589,210; €80,398,259 and €79,708,964 in the first, second and third year of the analyses. Incremental cost/patient comparing the addition of the B/N combination to the scenario only with methadone is €10.58; €6.98 and €7.34 in the first, second and third year respectively.
Addition of B/N combination would imply a maximum incremental yearly cost of €10.58 per patient compared to scenario only with methadone and would provide additional benefits.
Available from: PubMed Central
- "Naltrexone therapy may be useful in preventing relapse in patients who have withdrawn from opioids and/or those motivated enough to abstain from opioid use.20 However, the effectiveness of the antagonist-based approach has been somewhat disappointing and there is insufficient evidence to unequivocally support the clinical effectiveness of oral naltrexone in the treatment of opioid dependence.29,30 Its ineffectiveness can largely be traced to lack of patient adherence and retention. "
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ABSTRACT: 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.
Available from: Robert F Leeman
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ABSTRACT: Pathological gambling (PG) has recently been considered as a "behavioral" or nonsubstance addiction. A comparison of the characteristics of PG and substance use disorders (SUDs) has clinical ramifications and could help advance future research on these conditions. Specific relationships with impulsivity and compulsivity may be central to understanding PG and SUDs.
This review was conducted to compare and contrast research findings in PG and SUDs pertaining to neurocognitive tasks, brain function, and neurochemistry, with a focus on impulsivity and compulsivity.
Multiple similarities were found between PG and SUDs, including poor performance on neurocognitive tasks, specifically with respect to impulsive choice and response tendencies and compulsive features (e.g., response perseveration and action with diminished relationship to goals or reward). Findings suggest dysfunction involving similar brain regions, including the ventromedial prefrontal cortex and striatum and similar neurotransmitter systems, including dopaminergic and serotonergic. Unique features exist which may in part reflect influences of acute or chronic exposures to specific substances.
Both similarities and differences exist between PG and SUDs. Understanding these similarities more precisely may facilitate treatment development across addictions, whereas understanding differences may provide insight into treatment development for specific disorders. Individual differences in features of impulsivity and compulsivity may represent important endophenotypic targets for prevention and treatment strategies.
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