ATLANTA (CNN) — The first large head-to-head comparison of two opioid addiction medications found that, although they were equally effective in getting people off of high levels of opioids, users had a significantly more difficult time starting a regimen of naltrexone, compared with buprenorphine.

Nearly $1 Million Drug Helps Temple Student Battle Deadly Disease

Buprenorphine is commonly known by the the brand name Suboxone, and naltrexone is sold under the brand name Vivitrol.

The study, published Tuesday in the Lancet, looked at 570 patients with opioid addiction at eight inpatient treatment centers across the country for 24 weeks. Half of the group was assigned to naltrexone and the other half to bupenorphine.

Six percent of those enlisted to use buprenorphine were unable to start their treatment, whereas 28 percent of those assigned to naltrexone dropped out before starting the therapy.

That hurdle is attributed to the fact that in order to start naltrexone, a person has to have detoxed or not used opioids for several days, whereas a user can transition from opioids to buprenorphine seamlessly. “If you’re currently opiate-dependent … (naltrexone) takes more work,” said Dr. Joshua Lee, the lead author of the study, who studies opioid addiction behavior and treatment at New York University.

DA Approves First-Ever Pill With Digital Tracking System

Once on either of the medications, people fared equally well. “They tend to stay on medications about the same rate. They report good outcomes, avoiding heroin use,” Lee said. However, both groups also reported similar challenges staying with the regimens: Just 40 percent of patients still used the drugs after 24 weeks.

What was important, Lee said, was for opioid addicts as well as treatment providers to understand that addiction isn’t one-size-fits-all. “Much like you would expect if the doctor told you ‘you have cancer’ or ‘you have diabetes,’ then there are different ways you could pursue treatment,” he said.

The-CNN-Wire ™ & © 2017 Cable News Network, Inc., a Time Warner Company. All rights reserved.