Opioid dependence is one of the most severe drug dependencies. Naltrexone is a medication that completely blocks the subjective and other effects of opioids and, when administered to detoxified opioid addicts and taken as directed, prevents relapse and helps maintain abstinence. The major problem with naltrexone is poor compliance, particularly in countries in which there is a treatment alterna...

6beta-Naltrexol is the major metabolite of the opioid receptor antagonist, naltrexone, in humans. However, there are no functional studies of 6beta-naltrexol in primates. The aim of this study was to compare the in vitro and in vivo potencies of naltrexone and 6beta-naltrexol in rhesus monkeys. Affinity and potency were determined using radioligand displacement and stimulation of 5'-O-(3-[(35)S...

CONTEXT Clinical trials have suggested a modest effect of naltrexone as a pharmacotherapy for alcoholism, and a recent study has suggested that the effects may be moderated by variations in the mu-opioid receptor gene (OPRM1). However, the mechanism by which naltrexone may be differentially effective as a function of the OPRM1 genotype is unclear. OBJECTIVES (1) To replicate and expand on the...

INTRODUCTION AND AIMS Naltrexone implants are used to treat opioid dependence, but their safety and efficacy remain poorly understood. We systematically reviewed the literature to assess the safety and efficacy of naltrexone implants for treating opioid dependence. DESIGN AND METHODS Studies were eligible if they compared naltrexone implants with another intervention or placebo. Examined outc...

The behavioral effects of naltrexone and quaternary naltrexone were evaluated in two groups of pigeons. One group responded under a fixed-ratio schedule of food reinforcement and was trained to discriminate between 3.2 mg/kg morphine (i.m.) and saline. Drug-appropriate responding occurred in a dose-related manner to morphine, given intramuscularly and intraventricularly. When administered intra...

AIM To describe a situation in which an opioid-dependent patient overcame naltrexone blockade. DESIGN, CASE REPORT, SETTING: Addiction treatment center in St Petersburg, Russia. PARTICIPANT Patient with naltrexone implant. INTERVENTION Detoxification. MEASUREMENTS Clinical observations. CONCLUSIONS It is possible, but very difficult, to overcome naltrexone blockade by using large doses ...

BACKGROUND Respiratory depression, a potentially fatal side-effect of opioid-overdose, may be reversed by timely administration of an opioid antagonist, such as naloxone or naltrexone. Tampering with a formulation of morphine sulfate and sequestered naltrexone hydrochloride extended release capsules (MS-sNT) releases both the opioid morphine and the antagonist naltrexone. A study in recreationa...

The opioid antagonist naltrexone hydrochloride has been suggested to be a potential therapy at low dosage for multiple inflammatory conditions and cancers. Little is known about the immune-modulating effects of naltrexone, but an effect on the activity of toll-like receptor 4 (TLR4) has been reported. We analyzed the effects of naltrexone hydrochloride on IL-6 secretion by peripheral blood mono...

Naltrexone blocks the opioid receptors that modulate the release of dopamine in the brain reward system and therefore blocks the rewarding effects of heroin and alcohol. It is generally assumed that naltrexone leads to reduction of craving, but few studies have been performed to prove this. The purpose of the present study was to examine the effect of the administration of naltrexone on craving...