Common antidepressant offers fresh hope for people looking to reduce methamphetamine use in landmark trial
National Drug and Alcohol Research Centre (NDARC), UNSW Sydney
For the first time, people who want to stop using crystal methamphetamine may be able to treat their addiction with a cheap and readily available medication, say researchers at the National Drug and Alcohol Research Centre (NDARC), UNSW Sydney.
Results from the landmark Tina Trial, published in JAMA Psychiatry, show that adults who took mirtazapine – a generic antidepressant – were significantly more likely to reduce their methamphetamine use compared to those given placebo.
There are currently no approved medications available for people with methamphetamine use disorder.
“This is a game-changer,” said Chief Investigator Professor Rebecca McKetin, whose program of research focuses on stimulant use epidemiology and interventions.
“Ours is the first clinical trial in the world to definitively confirm that once-daily mirtazapine can be used to treat methamphetamine dependence in routine clinical practice.”
Professor McKetin said mirtazapine (sold under the brand names Avanza, Mirtanza and Axit in Australia) had a well-established safety profile and could be prescribed with limited clinical oversight.
“This is not a silver bullet but it’s a very important step forward and will encourage people struggling with methamphetamine use to seek support,” she said.
The Tina Trial enrolled 339 adults with moderate to severe methamphetamine use disorder, who were randomly assigned to receive either mirtazapine (30mg daily) or placebo for 12 weeks.
Participants were recruited from six outpatient clinics across the country. At the start of treatment, they used methamphetamine on 24 days out of the past 28 days on average.
The researchers found that people in the mirtazapine group reduced the frequency of their methamphetamine use by 7 days (out of the past 28 days) at the end of the treatment period, which was significantly greater than the 4.8-day reduction in the placebo group.
This represented an 8% decrease in the risk of methamphetamine use in those who received mirtazapine – in other words, 8 fewer days of methamphetamine use out of 100 possible use days.
Study co-author Shalini Arunogiri, an Associate Professor and National Health and Medical Research Council Emerging Leader at Monash University, said these benefits were modest but clinically important.
“Even small reductions in methamphetamine use can translate into meaningful improvements in health and well-being,” said Associate Professor Arunogiri, who is also an Addiction Psychiatrist and Clinical Director of Turning Point in Melbourne.
“For many people, this trial would also have been the first time they talked to a doctor about their drug use, which gives us an opportunity to address their other healthcare needs.”
While there were no unexpected safety concerns, more participants who took mirtazapine reported drowsiness and weight gain than those given placebo.
Associate Professor Arunogiri said most people who seek help for methamphetamine dependence also experience problems with mood and disrupted sleep patterns that can perpetuate the cycle of drug use.
“Having a medication that can address both their substance use and their mood and sleep problems is a real boon and allows us to provide a more integrated treatment approach.”
The Tina Trial was funded by the Medical Research Future Fund and was conducted in collaboration with Deakin University, Monash University, the University of Wollongong, and the University of Sydney, together with health services in Brisbane, Perth, Townsville, Adelaide, Geelong, and Wollongong.
Background
Methamphetamine is a highly addictive synthetic drug with powerful stimulant effect, and crystal methamphetamine or ‘ice’ – called that for its physical appearance – is the strongest and purest form of the drug.
Methamphetamine use disorder is a chronic relapsing dependence that affects an estimated 7.4 million people worldwide.
People with the disorder have a significantly elevated risk of harms including heart attack, stroke, kidney failure, viral infections such as hepatitis C and HIV, psychosis, suicide and self-harm, and premature death.
Contact details:
Media contact: For Prof McKetin, contact Kemal Atlay on [email protected] or 0401 713 850 | For A/Prof Arunogiri, contact Zali Rizmal on [email protected] or 0478 854 644.
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