Study: Extended-Release Naltrexone for Opioid Addiction Reduces Risk of Relapse

Vivitrol is only medication labeled for relapse prevention

In a multicenter, randomized clinical trial, former prisoners who received six monthly injections of extended-release naltrexone (Vivitrol, Alkermes, Inc.)––a medication that blocks opioid receptors in the brain––were significantly less likely to resume opioid use than were those who received counseling and referrals to community treatment centers without naltrexone. The study was published online in the New England Journal of Medicine.

The collaborative study included more than 300 men and women with opioid addiction who were treated at five study sites: the University of Pennsylvania in Philadelphia; the New York University Langone Medical Center; the Rhode Island Hospital and Brown University in Providence; the Columbia University Medical Center in New York; and the Friends Research Institute in Baltimore, Maryland.

Of the study participants who received counseling and referrals, 64% relapsed within six months compared with 43% of those treated with long-acting naltrexone. Although some of the participants in the naltrexone group relapsed, they used significantly less heroin and other opioids than did those in the control group. In addition, there were no overdoses in the treatment group compared with five in the control group. One year after the initial study period, the control group had two additional overdoses compared with none in the naltrexone group.

Opioid addiction has become a public health crisis in the United States. According to the Centers for Disease Control and Prevention, drug overdoses, largely from opioids, killed more people than automobile accidents in 2013. Opioid addiction remains disproportionately high in the U.S. criminal justice system populations.

Two opioid substitution strategies––methadone maintenance and buprenorphine maintenance––are effective in reducing relapse and overdose risk among opioid-dependent individuals, but these medications are neither acceptable nor effective for all patients. Naltrexone, an opioid receptor blocker, uses a different mechanism, thus expanding available treatment options for people who are dependent on opioids, according to the authors.

“Dependence on opioids, including heroin and prescription painkillers, is a medical disease that has become increasingly pervasive throughout our urban, suburban, and rural areas and across all socioeconomic groups,” said co-author Edward V. Nunes, MD, a professor of psychiatry at Columbia University. “It is hard to underestimate how deadly and devastating this disease is. It is a top killer of young people. Having another medication that is capable of reducing the risk of relapse and preventing overdoses is critical in the fight against opioid dependence.”

All of the study participants were encouraged to seek community-based treatment, regardless of treatment group, for another year after the initial six-month study period. Community-based treatment often includes counseling and daily therapy with methadone or suboxone––medications that prevent withdrawal symptoms by activating opioid receptors.

Extended-release naltrexone is the most recently FDA-approved product for the treatment of opiate addiction and the only one labeled for the prevention of relapse. A daily, oral form of naltrexone has been on the market since 1994, but adherence to daily pill-taking was often poor. Extended-release naltrexone, approved in 2010, requires only one monthly injection, which circumvents problems with adherence to daily pill-taking, the authors point out.

Source: EurekAlert; March 30, 2016.