According to recent results from the SYMBAD trial, the anti-depressant mirtazapine may not be an effective treatment for agitation in Alzheimer’s disease (AD). During his presentation at the Clinical Trials in Alzheimer’s Disease conference in early December, Prof. Sube Banerjee (University of Plymouth, UK) explained that SYMBAD participants receiving mirtazapine had similar scores on a clinical scale for agitation as participants who received a placebo instead of the drug.
Mirtazapine is an antidepressant used to treat major depressive disorder, and works by increasing levels of mood-enhancing chemicals serotonin and noradrenaline in the brain. Antidepressants such as mirtazapine are often prescribed to treat agitation associated with dementia, although the clinical value is unclear. SYMBAD was a double-blind, controlled, Phase 3 clinical trial designed to assess the safety and efficacy of mirtazapine as a treatment for agitation in people with AD. 244 participants with AD dementia and agitation were randomised to receive oral mirtazapine or a placebo control for a period of 12 weeks, after which they were followed up for a year.
While mirtazapine did not have a beneficial effect on agitation when compared to placebo, results presented by Prof. Banerjee showed that agitation was reduced in both mirtazapine and placebo groups in the first 12 weeks of the clinical trial, perhaps linked to the enhanced medical care and support provided to trial participants. However, there was a slight increase in mortality in the mirtazapine arm of SYMBAD at week 16 (7 participants, compared to 1 in the placebo group), with Prof. Banerjee emphasising a need for caution in prescribing anti-depressant drugs such as mirtazapine for agitation linked to AD dementia. Read the Lancet article on the SYMBAD trial, here:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01210-1/fulltext#seccestitle170
