Could Mirtazapine Be Used to Ease Opioid Withdrawal?

Mirtazapine, an atypical antidepressant used to treat major depressive disorder, may also relieve several symptoms of opiate discontinuation, according to the findings of a recent study.

“The implications may be decreased polypharmacy, decreased drug adverse reactions and multiple drug?drug interactions, and a higher likelihood of completing withdrawal without relapse,” said study author Elisha Lalani, BBA, MD, MPH, an internal medicine specialist at the University of Texas Department of Internal Medicine, in San Antonio.

The literature review cited both clinical and basic science studies to demonstrate how mirtazapine treats each of the following symptoms:

• Nausea and vomiting: Mirtazapine exerts antagonistic effects on the 5-HT3 receptor, giving the drug antiemetic properties.
• Diarrhea: Mirtazapine blocking of serotonergic pathways via 5HT receptors has been shown to reduce diarrhea, abdominal pain and discomfort in patients with irritable bowel syndrome.
• Anxiety, jitteriness, jumpiness and depression: Mirtazapine eases these symptoms by increasing dopamine levels.

Importantly, mirtazapine can be taken with medications for opioid use disorder (OUD), like methadone and buprenorphine, but researchers caution that rare (and likely dose-dependent) complications can cause life-threatening serotonin syndrome. Therefore, like anyone withdrawing from opioids, people administered mirtazapine should be monitored for serious symptoms or interactions by a physician.

The World Health Organization’s standard-of-care guidelines for treating drug dependence call for doctors to address patients’ discomfort when admitted to treatment. Several drugs are currently used to manage withdrawal, which increases the risk for harmful drug interactions.

The research cited in the study was for the use of mirtazapine for diagnoses other than OUD, and “it’s possible that the effects of mirtazapine may not be exactly the same when used for OUD,” Lalani said, “although we would expect it to be.”

She also advocated for more research, including head-to-head clinical trials of current methods of treating OUD and mirtazapine.

—Myles Starr

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