Researchers found that monthly injections of extended-release naltrexone -- which blocks the euphoric effects of opioids -- resulted in a significantly lower relapse rate among treated addicts compared to a similar group that didn't receive the drug. Additionally, during the six-month study there were no overdoses in the naltrexone group compared to five in the other group.
Opioids -- including prescription painkillers such as OxyContin, Vicodin and Percocet, as well as the street drug heroin -- killed more than 28,000 people in 2014, a record high, according to the U.S. Centers for Disease Control and Prevention.
"We thought this was a good approach to relapse prevention . . . but I was surprised by how clearly effective this medication was," said study author Dr. Joshua Lee, an associate professor in the department of population health at NYU Langone Medical Center, in New York City.
"We haven't had another study like this in the United States," Lee added. "This is potentially a very important study if a [health care] provider wasn't convinced before that they should offer naltrexone. They may be less skeptical now."
The study is published in the March 30 online issue of the New England Journal of Medicine.
An extended-release version of naltrexone, known also by the brand name Vivitrol, is the most recently approved product by the U.S. Food and Drug Administration to treat opiate addiction, and the only drug labeled for relapse prevention. Other anti-addiction medications include methadone and buprenorphine.
At five sites in four major U.S. cities, Lee and his team administered monthly injections of naltrexone to 153 opioid-addicted adults who had had some criminal justice involvement. A similar group of 155 participants did not receive the drug but were referred for "usual care" consisting of brief counseling and referrals to community treatment programs.
After six monthly injections, 43 percent in the treatment group had relapsed, compared to 64 percent of those who didn't receive naltrexone. The average time elapsing before relapse was double in the naltrexone group.
Follow-up one year after the treatment ended found both groups were using opioids at a similar rate. And two additional overdoses had occurred in the non-naltrexone group and none in the treatment group.
Lee and another addiction expert agreed that these results suggest naltrexone therapy should be used longer than six months.
"Addiction is a chronic brain disorder, and the brain changes under the influence of drugs," said Dr. Terry Horton, chief of addiction medicine at Christiana Care Health System, in Wilmington, Del. Drugs "hijack" critical parts of the brain involved with motivation and reward, and "those changes take a long time to heal," he said.
"So medications facilitate moving toward recovery," he said, "but this requires a long-term effort, as with all chronic diseases."
Horton said the new research provided "hopeful" results that were similar to those done in other countries.
"My hope is this will provide another tool in the tool chest to help care for individuals who are in the criminal justice system and moving back into society so they can address their opiate dependence," Horton said. "The models of care we see in the prison population can also be generalized to the greater population. Opiate dependence is, sadly, a disease that's cutting across all socioeconomic, racial and gender boundaries. It's affecting everyone."
In an effort to curb the national epidemic of prescription painkiller abuse, the FDA and CDC announced new initiatives this month. The FDA moved to label certain drugs with "boxed warnings" that notify users of the dangers of misuse, while the CDC instituted tough new guidelines for doctors prescribing prescription painkillers.
Lee and Horton agreed that more research on anti-addiction treatments is necessary, particularly to compare the effectiveness of naltrexone to other anti-addiction drugs.
"But I don't know that we need a ton more research on this to say, why don't we use these?" said Lee.
"Right now, there's no debate or argument that going on medications is a better approach," he added. "If you're not using medications, you're not really practicing effective evidence-based medicine."
More information The U.S. National Institute on Drug Abuse offers more information on opioids.
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