According to the new research published in The Lancet, Opioid treatment drugs have similar outcomes once patients initiate treatment

The study was conducted at eight sites within the National Institute on Drug Abuse Clinical Trials Network.

A study comparing the effectiveness of two pharmacologically distinct medications used to treat opioid use disorder – a buprenorphine/naloxone combination and an extended release naltrexone formulation – shows similar outcomes once medication treatment is initiated.

Among active opioid users, however, it was more difficult to initiate treatment with the naltrexone. Study participants were dependent on non-prescribed opioids, 82 percent of them on heroin, and 16 percent on pain medications.

Five hundred and seventy opioid-dependent adults were randomized to the buprenorphine combination or the naltrexone formulation, and followed for up to 24 weeks of outpatient treatment. Study sites differed in their detoxification approaches and in their typical inpatient length of stay. Buprenorphine/naloxone (brand name Suboxone) was given daily as a sublingual film (under the tongue), while naltrexone (brand name Vivitrol) was a monthly intramuscular injection. Adverse events, including overdoses, were tracked.

Nora D. Volkow, M.D., director of NIDA said, “Studies show that people with opioid dependence who follow detoxification with no medication are very likely to return to drug use, 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, and these important results come at a time when communities are struggling to link a growing number of patients with the most effective individualized treatment.”

Scientists conducting the research expected that it would be more difficult to initiate treatment with naltrexone because it requires a full detoxification, and patients often drop out of that process early. However, both the extent of the detoxification “hurdle,” and how the medications would compare once they were initiated, was not known. 

Researchers note that patients who are unable to complete detoxification and choose naltrexone should be strongly encouraged to initiate the buprenorphine combination treatment, and that improved methods to transition active users to naltrexone need to be developed.

The buprenorphine combination is a partial agonist, while the naltrexone is an antagonist. Their approaches to treating opioid dependence are pharmacologically, conceptually, and logistically different.

A partial agonist still activates opioid receptors, but less strongly, reducing cravings and withdrawal symptoms. It is considered opioid maintenance treatment. An antagonist blocks the activation of opioid receptors, preventing opioids from producing the euphoria. There must be no opioids left in the body before beginning this treatment. So, there are differences in initiating treatment and withdrawal on discontinuation. Until now, these have never been compared head-to-head in the United States, so there have never been the comparative effectiveness data needed to make informed choices.

John Rotrosen, M.D., the study lead investigator said, “The good news is we filled the evidentiary void, and also learned that for those who were able to initiate treatment, the outcomes were essentially identical, as were adverse events. This gives patients the freedom to choose a treatment approach that best suits their lifestyle, goals and wishes.”