Study Cautions Against Use of Mirtazapine to Treat Agitation in Dementia Patients

Pavankumar Kamat

October 28, 2021

New research published in  The Lancet  suggests that mirtazapine, which is commonly used to treat agitation in patients with dementia, has no benefit over placebo and could also potentially increase mortality risk.

The Study of Mirtazapine for Agitated Behaviours in Dementia trial (SYMBAD) was led by the University of Plymouth in collaboration with several other UK universities and research organisations.

Non-pharmacological patient-centred care remains the first-line treatment of dementia-related agitation; however, there is an unmet need for effective drug treatments when patients do not adequately respond to non-drug treatment.

The double-blind, parallel-group, SYMBAD trial included 204 patients with probable or possible Alzheimer's disease, agitation unresponsive to non-drug treatment and a Cohen-Mansfield Agitation Inventory (CMAI) score of ≥45, identified from 26 centres across the UK. The patients were randomly assigned (1:1) to receive either mirtazapine (titrated to 45 mg) or placebo. The primary outcome was reduction of agitation, assessed by the CMAI score at 12 weeks.

There was no significant difference in the mean CMAI scores at 12 weeks between the mirtazapine and the placebo groups (adjusted mean difference, −1.74; 95% CI, −7.17 to 3.69; P=.53).

The frequency of adverse events was comparable in the mirtazapine and placebo groups (66% vs 64%). More deaths occurred in the mirtazapine group (n=7) compared with the placebo group (n=1) by week 16; however, the statistical significance was marginal (P=.065) in the post-hoc analysis.

The study's lead researcher, Professor Sube Banerjee from The University of Plymouth, said in the university's press release: "This study shows that a common way of managing symptoms is not helpful – and could even be detrimental. It’s really important that these results are taken into account and mirtazapine is no longer used to treat agitation in people with dementia."

Commenting on the findings, Dr Richard Oakley, Head of Research at Alzheimer’s Society, stated: "Unnecessary prescribing of antipsychotics to people with dementia is dangerous and associated with a higher risk of death, which is why we’ve been campaigning hard to reduce levels since the late 90s, saving tens of thousands of lives."

Dr Oakley added: "While only a small study, these results suggest a rethink is needed. Not only was the drug ineffective at reducing agitation, it was associated with more deaths, suggesting mirtazapine should be avoided in Alzheimer’s – and research carried out to understand its effects in other types of dementia."

The research was funded by the UK National Institute for Health Research Health Technology Assessment Programme.

This article originally appeared on Univadis, part of the Medscape Professional Network.


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