In what may signal a seismic shift in the treatment of methamphetamine addiction, a pair of prescription drugs appears to help patients significantly reduce their stimulant use, or quit altogether.
The combination therapy involves an injectable medication called extended-release naltrexone and a daily generic pill called bupropion.
Naltrexone, which is already used to treat opioid and alcohol addiction, helps curtail the euphoria and cravings that typify meth addiction.
Bupropion is an antidepressant previously deployed to treat nicotine addiction.
In prior testing, neither of these meds was effective when taken individually. But between 2017 and 2019, more than 400 adults with moderate-to-severe methamphetamine use disorder participated in a combination treatment trial, and the results suggest the combination works.
"Methamphetamine addiction is very difficult to treat," explained Dr. Nora Volkow, director of the U.S. National Institute on Drug Abuse, or NIDA, which funded the study.
"While behavioral interventions can be useful, there are currently no approved medications to help treat it," Volkow said.
And that's a huge concern, because "methamphetamine is rapidly rising in our country, with an estimated 39% increase in one year," said Volkow, who was not part of the study team.
A separate NIDA study finds that methamphetamine overdose deaths in the United States surged from 2011 to 2018, increasing fivefold in just eight years. That report was published Wednesday in JAMA Psychiatry.
Volkow said the "synergistic" power of the new combination therapy is good news, amounting to the largest effect seen from a large, randomized clinical trial in the treatment of methamphetamine use disorder.
Standard behavioral treatment for meth addiction typically involves highly structured group therapy, Volkow explained.
Another option is a rewards-based motivational therapy, involving monetary incentives, although this controversial approach is largely deployed outside the United States.
The study was led by Dr. Madhukar Trivedi, a professor of psychiatry at UT Southwestern Medical Center in Dallas.
All participants were outpatients seeking to get their addiction under control at one of several treatment clinics across the country. The study unfolded in two stages over three months.
In the first stage, patients -- age 18 to 65 -- were divided into two groups.
One was given the combination therapy, which involved a shot of naltrexone every three weeks along with a daily dose of bupropion. The other group was given placebo shots and pills.
Urine drug screening was conducted four times in each stage.
Those in the placebo group who saw no improvement by week six were rolled over into the second stage, and then randomly reassigned to either a new treatment group or another placebo group.
Success was defined as three clean drug screenings out of four.
At weeks 5 and 6 nearly 17% of the combo treatment group met that threshold, versus 3% of the placebo group.
By weeks 11 and 12, those figures were roughly 11% versus less than 2%. And the treatment significantly reduced cravings and boosted quality of life, both without serious side effects, researchers reported.
Not that naltrexone plus bupropion is a sure thing. The team projects that for every nine treated patients only one will succeed.
And because naltrexone is not a generic, "this treatment, if approved, may be associated with some cost," Volkow said. But "societal costs surrounding methamphetamine addiction are [also] high and rising," she added.
In all likelihood, "these medications will now be used 'off-label' by physicians to treat their patients with methamphetamine addiction," while research continues, Volkow said.
That research is badly needed, cautioned Linda Richter, vice president of prevention research and analysis with the Partnership to End Addiction in New York City.
"The overall effectiveness was positive, but small," Richter noted. "The duration of the study and size of the sample were limited, and the question remains as to whether using the medication combination in conjunction with behavioral therapies would enhance its effects."
Nevertheless, if further research is similarly positive, she said, "the medication combination should be made widely available and be covered by public and private insurance."
The study results were published last week in the New England Journal of Medicine.More information
There's more on meth abuse at the U.S. National Institute on Drug Abuse
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