Two medicines used to treat opioid use disorder—buprenorphine/naloxone (Suboxone) and extended-release naltrexone (Vivitrol)—have similar outcomes if the patient adheres to the treatment, according to a 24-week study of 570 opioid-dependent adults.
The researchers expected that it would be more difficult to initiate treatment with naltrexone because it requires full detoxification, and patients often drop out of the process. And indeed, fewer patients successfully initiated naltrexone, compared with buprenorphine/naloxone (72% vs 94%). The 24-week relapse rates were slightly higher for naltrexone: 65%, compared with 57% for buprenorphine/naloxone, mainly due to early relapse in the naltrexone group.
But among the 474 patients who successfully started on medication, the relapse rates were similar: 52% for naltrexone vs 56% for buprenorphine/naloxone.
Other outcomes among patients who began treatment—days abstinent, negative urine tests, and time to relapse—generally favored buprenorphine/naloxone in the full group, the researchers say. When only those who initiated treatment were considered, the outcomes slightly favored naltrexone.
During the study, 5 people had fatal overdoses: 3 in the buprenorphine/naloxone group and 2 in the naltrexone group. However, overall overdose rates, including nonfatal overdose, were low compared with what would be expected in this population, the researchers say. Their findings “strongly support” the conclusion that medication protects against overdose.
“Studies show that people with opioid dependence who follow detoxification with no medication are very likely to return to drug use,” said Nora Volkow, MD, director of the National Institute on Drug Abuse. “Yet many treatment programs have been slow to accept medications that have proven to be safe and effective. These findings should encourage clinicians to use medication protocols.”