Findings in a Phase III clinical trial released by NIH showed that a combination of two medications—injectable naltrexone and oral bupropion—were safe and effective in the treatment of adults with moderate or severe methamphetamine use disorder.
Results of the study, which was conducted at multiple sites within the NIDA Clinical Trials Network, were published late Wednesday by the New England Journal of Medicine.
Unlike for opioids, there are currently no approved medications for treating methamphetamine use disorder, leaving providers to treat the illness with other approaches, such as cognitive behavioral therapy and contingency management interventions. The study could mark a significant step toward making MAT a viable modality for methamphetamine use disorder.
The study was conducted at multiple community treatment programs across the nation from 2017 to 2019, with 403 adult volunteer participants between the ages of 18 and 65, all of whom had moderate or severe methamphetamine use disorder. The patients were divided into treatment and control groups. Treatment group participants were injected with extended-release naltrexone every three weeks in each of two six-week stages. They also were given extended-release bupropion tablets each day. The control group participants were given matched injectable and oral placebos on the same schedule.
At the end of each stage, participants were given urine drug screenings. They were considered to have responded to treatment if they tested negative at least three out of four times. After weeks 5 and 6, 16.5% of the treatment group responded to treatment vs. 3.4% of the control group. After weeks 11 and 12, 11.4% of the treatment group responded vs. 1.8% of the control group. Adherence to treatment was high among both groups—77.4% for treatment participants and 82.0% for placebo participants in the final six weeks of the program.
Participants in the treatment group also reported fewer cravings and greater improvements in their lives, as measured by a Treatment Effectiveness Assessment. No significant adverse effects in the dual-medication treatment were reported.
NIH noted in a news release that in previous studies, naltrexone and bupropion administered alone “showed limited, inconsistent efficacy” for treating methamphetamine use disorder, but administering them together appears to have potentially created “an additive or synergistic effect.”