Methamphetamine – commonly known as crystal meth, crystal, or ice – is a highly addictive stimulant.
An estimated 7.4 million people worldwide are dependent on or “addicted” to it. They face multiple health risks, including increased risk of paranoia, suicidal thoughts, heart disease, stroke, accidental injury, and premature death.
However, there are no drugs approved anywhere in the world to treat stimulant addiction.
Cheap, safe and readily available drugs that have been used for years to treat depression are now showing promise. Our trial of mirtazapine, just published in JAMA Psychiatry, shows that people who take mirtazapine reduce their use of stimulants.
Few other options
Australia has one of the highest numbers of people addicted to stimulants per capita in the world.
There are no approved drugs for methamphetamine addiction anywhere in the world, so there are few treatment options.
Treatment options currently available include counseling, detoxification or withdrawal, and long-term residential rehabilitation. However, access can be difficult and treatment dropout rates are high. Most people who go to rehab will relapse.
More advanced treatments offered within the community, such as contingency management, which involves setting goals and rewards for achieving them, are more effective but are not widely available.
Even though there are no drugs approved for methamphetamine use, doctors may prescribe existing drugs that have shown promise in clinical trials.
Medications prescribed off-label include prescription stimulants (methylphenidate, lisdexamfetamine, modafinil), the smoking cessation drug bupropion, the opioid blocker naltrexone (including in combination with bupropion), and antidepressants.
However, these drugs may be ineffective and may cause unnecessary side effects and safety risks.
What about mirtazapine?
Recent research suggests that the antidepressant drug mirtazapine may offer hope.
In the United States, two studies were conducted at an outpatient research clinic in San Francisco, California. Both trials found that mirtazapine reduced stimulant use.
These first clinical trials were conducted in research clinics with small groups of carefully monitored patients (60 and 120, respectively). The patient was at risk for HIV and was a transgender woman who has sex with men. Women and patients with depression were excluded.
So our Australian team wanted to find out whether mirtazapine would have the same benefits when used by doctors in community clinics to treat a larger, more diverse group of patients.
What we did and what we found
The Tina trial recruited a larger, more diverse sample of 339 people dependent on stimulants from six outpatient clinics in Australia.
At the start of the trial, participants had used stimulants for an average of 22 of the previous 28 days.
Half were randomly assigned to either take home mirtazapine (30 milligram tablets per day) or a placebo for 12 weeks. The researchers then tracked the days participants used stimulants over a 12-week period.
People who received mirtazapine reduced their stimulant use more than those who received a placebo (7 out of 28 days reduction compared to an average of 4.8 days).
Therefore, the comparative advantage of mirtazapine was modest, with a duration of use of 2.2 out of 28 days.
This benefit was evident regardless of whether people had depression at the start of the study.
Although this reduction is small, it is an important step forward in the absence of alternative treatments.
Our research team believes that mirtazapine has a direct impact on stimulant dependence, independent of its ability to reduce depression.
This suggests that mirtazapine is acting directly on brain systems involved in drug reward and may restore function in pathways that can be disrupted by long-term stimulant use.
Our study found no unexpected safety issues when using mirtazapine to treat stimulant dependence. The most common side effects were drowsiness and weight gain.
This is not a “cure”
Mirtazapine is not an immediate “cure” for stimulant dependence. However, with no medicines approved for methamphetamine use worldwide, providing medicines that reduce the harms caused by methamphetamines is an important first step.
Mirtazapine is cheap, safe, and readily available. Many doctors are familiar with its use in treating depression.
Since it is a household medicine, it is easy to use. Therefore, daily clinic visits and close medical monitoring are not required.
It is also “off-patent”, meaning there is a cheaper generic version.
For mirtazapine to be routinely prescribed for stimulant dependence outside of clinical trials, regulatory authorities must approve it for this purpose. This requires research evidence like that provided in the Tina trial.
In the meantime, doctors can prescribe mirtazapine off-label. Guidelines on off-label prescribing of medicines are available from the Royal Australian and New Zealand College of Psychiatrists.
Learn more about the Tina trial here.
If you are concerned about your own or someone else’s drug or alcohol use, please call the National Alcohol and Other Drug Hotline on 1800 250 015. This hotline is open 24 hours a day, seven days a week, and provides free, confidential information and support.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
