Deaths resulting from drug overdose have escalated by 137 percent from 2000 to 2014 in the United States, according to a recent report from the Centers for Disease Control and Prevention (CDC). The number of drug-related deaths in 2014 was greater than any reported in past years, with more than three out of five drug overdose mortalities involving the use of opioids such as prescription opioids and heroin.
In response to this epidemic of drug abuse, and specifically the abuse of opioids, the CDC has urged the implementation of safer opioid prescription practices. But some physicians have argued that improving treatments for opioid addiction is just as pressing and critical an issue as preventing opioid abuse in the efforts to combat this widespread problem.
For patients rehabilitating from opiate addiction, doctors often prescribe methadone, a synthetic opioid, to reduce the patients’ physical drug cravings and to prevent traumatic withdrawal symptoms. By occupying the receptors in the brain that are stimulated by other opioids, methadone enables a majority of patients to gradually ease away from opiate addiction. Yet, there remain legitimate, evidence-based concerns that the patients then become addicted to methadone instead.
In the search for alternatives to opioid-maintenance regimens such as methadone, antagonist drugs such as naltrexone (Vivitrol) have been suggested in a limited number of studies to be more efficacious than methadone.
Extended-release naltrexone in particular has become an increasingly accepted treatment regimen for patients seeking a relapse-prevention drug due to its relatively low required dosage. Unlike other opiate dependence medications such as methadone, extended-release naltrexone, when it is injected requires monthly rather than daily dosing.
To investigate whether extended-release naltrexone is effective at preventing opioid relapse, researchers at the Center for Studies of Addiction at the Perelman School of Medicine at the University of Pennsylvania conducted a randomized trial among adult criminal justice offenders who were recovering from opioid dependence. As described in the study, which was published last month in the New England Journal of Medicine, the investigation enrolled ex-heroin users who expressed a desire to undergo opioid-free treatment.
At the time of randomization, all of the participants were confirmed to be opioid-free based on negative urine toxicological screening. Moreover, the participants had to be free of any other drug or alcohol dependence necessitating care that would conflict with participation in the trial. Once the randomization of the participants was complete, a total of 153 individuals had been assigned to the extended-release naltrexone group and a total of 155 participants to the usual treatment group.
Over the course of 24 weeks, the 153 participants in the extended-release naltrexone group were administered naltrexone once every four weeks during medical management visits, during which the participants also received counseling sessions and referrals for community treatment programs. The 155 test subjects of the usual treatment group, however, were only given counseling sessions and recommendations for community programs.
To monitor the incidence of opioid relapse in both groups, the researchers also followed up with the trial participants every two weeks during the 24-week treatment period and afterwards assessed the test subjects’ conditions at weeks 27, 53 and 78. Urine toxicological screenings for opioid use were carried out during these visits. In addition, the investigators asked the participants to report the consumption of opioid, cocaine, alcohol or other drugs during the two-week period.
The self-reported information, as the investigators noted, was correlated with the rates of opioid relapse as evidenced by the toxicological screenings. During the 24-week treatment phase, the individuals who were taking extended-release naltrexone took a longer median time to relapse (10.5 weeks) than did the participants who received only the usual treatment (five weeks). The extended-release naltrexone group also demonstrated a lower rate of relapse (43percent) than the usual treatment group (64 percent).
Naltrexone, however, did not produce a significant decrease in the participants’ consumption of other drugs and alcohol, as both naltrexone and control groups showed similar usage rates. Moreover, the preventative effects of naltrexone wore off after treatment was discontinued. At week 78, about a year after the end of the treatment phase, the rates of negative opioid toxicological tests were equal in the two groups at 46 percent.
Nevertheless, over the entire 78 weeks, no opioid overdose cases were observed in the extended-release naltrexone group while seven cases were reported in the usual treatment group. The greater potency of extended-release naltrexone over the usual abstinence-based program is supported by this investigation. This showed that naltrexone can not only lower the rate of opioid relapse, but also prevent cases of opioid overdose in the long term.
The investigators of this project, however, note that more research is required to determine whether a more continuous regimen of naltrexone would further extend its beneficial effects. While more research is indeed necessary to test the effectiveness of naltrexone over standard opioid maintenance drugs such as methadone, naltrexone has become an increasingly appealing, non-addictive alternative to methadone for the treatment of opioid dependence.