Dual-drug therapy reduces methamphetamine use: UCLA study

A clinical trial of dual-drug therapy to treat methamphetamine use disorder showed a reduction in use of the highly addictive drug within 12 weeks of treatment, a UCLA-led study suggests.

Participants in the ADAPT-2 clinical trial who received the combination of injectable naltrexone and extended-release oral bupropion (NTX+BUPN) showed a 27% increase in negative tests for methamphetamine, indicating a decrease in drug use. For comparison, in the placebo group this figure was 11%.

The study was published in Addiction magazine.

“These findings have important implications for the pharmacological treatment of methamphetamine use disorder. There is currently no FDA-approved medication to treat it, while the number of overdoses associated with methamphetamine has increased significantly over the past decade,” said Dr. Michael Lee, assistant professor of family medicine at the David Geffen School of Medicine at UCLA and lead author of the study.

Meth use continues to increase worldwide, increasing from 33 million people in 2010 to 34 million in 2020. 

To contain the current crisis, the National Institute on Drug Abuse (NIDA) has supported various trials, including the ADAPT-2 trial, to test the effects of various pharmacological treatments for methamphetamine use disorder. ADAPT-2 was conducted from May 23, 2017 to July 25, 2019 at eight test sites, including UCLA. The study included 403 people, of whom 109 were assigned to the combination treatment group and the rest to the placebo group in the first stage.

The latest results relate to the second stage of a multicenter trial. The previous phase showed that the combination of the two drugs was effective in the sixth week, but the question remained whether the effectiveness of the treatment was maintained over a longer period.

In the second phase, researchers conducted urine tests on participants at weeks seven and twelve, and post-treatment at weeks thirteen and sixteen, comparing the NTX+BUPN group with the placebo group.

Further research is needed to determine whether treatment effects last beyond 12 weeks and lead to further reductions in methamphetamine use, the researchers write.

“Previous treatment trials for stimulant use disorder suggest that change in use occurs gradually (consistent with our findings), is unlikely to lead to sustained abstinence over the course of a typical 12-week trial, and is dependent on the duration of treatment.”, they write. "This requires future clinical trials to quantify changes in methamphetamine use beyond 12 weeks and to determine the optimal duration of treatment with this drug."