Lee 2018 (X:BOT): Vivitrol vs Suboxone for opioid relapse

What they tested

At eight US community-based inpatient services, 570 adults with opioid use disorder who had used non-prescribed opioids in the past 30 days were randomly assigned to monthly extended-release naltrexone injections (Vivitrol) or daily buprenorphine-naloxone film under the tongue (Suboxone). They were followed as outpatients for 24 weeks, and everyone knew which drug they got.

The main measure was opioid relapse-free survival. Relapse meant 4 weeks in a row of any non-study opioid use by urine test or self-report, or 7 days in a row of self-reported use.

What they found

Starting Vivitrol was the main hurdle: 204 (72%) of 283 people started it, against 270 (94%) of 287 on Suboxone.

Counting everyone randomized, relapse by 24 weeks was more common on Vivitrol, 185 (65%) of 283, than on Suboxone, 163 (57%) of 287 (hazard ratio 1.36). Most or all of that gap came from early relapse in people who never started Vivitrol: 70 (89%) of 79 relapsed.

Among the 474 people who did start their medicine, relapse rates were similar (p=0.44), as were opioid-negative urine tests and opioid-free days. Counting everyone, those measures favoured Suboxone.

Craving was lower on Vivitrol at first, and the groups converged by week 24. Apart from mild-to-moderate injection site reactions on Vivitrol, side effects, including overdose, didn't differ. Five people died of overdose: two in the Vivitrol group and three in the Suboxone group.

Limits

• It was open-label, so patients and staff knew who got which medicine.
• Everyone started at inpatient services, so the results may differ for people starting treatment as outpatients.
• It lasted 24 weeks, so it doesn't show what happens over longer periods.

What it means if you're considering naltrexone

For someone choosing between the two, X:BOT's message is that Vivitrol is harder to start, because people have to be off opioids first, but once someone is on it, it seemed to work about as well as Suboxone over 24 weeks. The authors call for better ways to get people started on the shot and to keep people in treatment on both medicines.