Naltrexone hydrochloride is a medication used in the treatment of opioid addiction. Approved by the Food and Drug Administration in 1985 for use in opioid dependence, the medication works by antagonizing opioid receptors and blocking the effects of opiates (usually in the form of heroin) consumed by addicts. Naltrexone can help patients avoid relapse in the early stages of detoxification treatment without increasing the severity of withdrawal symptoms. The medication is usually prescribed as part of a drug treatment program that includes counseling and other support services.
A typical treatment regimen will vary by patient, depending on the extent of the opioid addiction. Some patients are required to take daily doses (usually 50mg per day), while other patients receive higher doses (100mg to 150mg) two or three times each week. Once a patient has detoxified from opioids and has stabilized on naltrexone, regular opioid drug use has little if any effect. Patients discover that intake of even large doses of opioids no longer produces the same effects as it once did. Opioid-seeking behavior can be reduced as long as patients continue to take naltrexone as prescribed, especially in conjunction with other drug treatment approaches, such as individual counseling sessions.
Despite the potential positive effects of naltrexone, the treatment is not always readily accepted by individuals with opioid addiction. Also, patient noncompliance with daily oral dosing protocols can hinder the effectiveness of the medication. There are several reasons these populations may be reluctant to try naltrexone. First, naltrexone treatment requires abstinence from all opioid use, and an individual must remain opioid free for at least 5 days. Many opioid addicts are unable to successfully detoxify and control their drug use for that length of time. Also, naltrexone, unlike other medications for opioid dependence such as methadone, has no opioid agonist effects and produces no physiological dependence. Thus, naltrexone does not provide patients with a positive mood state, and patients can stop taking the medication at any time without experiencing withdrawal symptoms.
Because noncompliance with daily or weekly naltrexone treatment is such an issue, some recent clinical research has begun to explore the effects of using naltrexone implants with opioid-dependent patients. The implants, which are either inserted or injected into patients, allow for sustained-release preparations of naltrexone medication over a period of months, instead of days, thereby reducing the number of subsequent treatment visits. The research is still preliminary, and the FDA has only recently approved use of an extended-release form of naltrexone administered by intramuscular injection once a month (FDA News Release 2010).
Though there have been numerous studies examining the efficacy of naltrexone treatment on opioid-addicted populations, there have been only a few studies that have specifically examined treatment effects on criminal justice–involved populations (Patapis and Nordstrom 2006).
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In the study by Cornish and colleagues (1997), only 52 percent of the experimental group remained on naltrexone for the entire study period. The highest rate of dropout occurred during the first month of the study (the majority occurred within the first week). Thirty-three percent of the control group was retained through the entire study. The retention rate for the experimental group was not significantly higher than the control group.
Study participants receiving naltrexone had an average of 8 percent opioid-positive specimens, while members of the control group averaged 30 percent positive specimens. Overall drug use in the control group was higher than the experimental group. However, the only significant difference was in use of opioids (8 percent of the experimental group, compared with 30 percent of the control group). Cocaine use among both groups remained high (33 percent of the experimental group and 49 percent of the control group), but the difference was not significant.
The experimental group receiving naltrexone was significantly less likely to be reincarcerated. Among the experimental group, 26 percent were reincarcerated for a probation violation, compared with 56 percent of the control group.