Quetiapine for Major Depressive Disorder: A Review of Clinical Effectiveness, Cost-Effectiveness, and Guidelines

Key Message

This review included four systematic reviews, one randomized controlled trial, and six economic studies. Two evidence-based guidelines on the use of quetiapine for treatment of patients with major depressive disorder were identified. 
Based on findings from a network meta-analysis, quetiapine monotherapy in older adults with major depressive disorder was found to be more efficacious compared to several antidepressants; however, However there remain uncertainty regarding the robustness of these findings, given the lack of available comparative data.

The efficacy of quetiapine add-on therapy in patients with treatment-resistant depression, characterized by response rate, remission rate, or depressive symptoms was not significantly different compared to competing interventions including other atypical antipsychotics, antidepressants, and lithium. Quetiapine add-on therapy and quetiapine monotherapy were associated with higher withdrawals due to adverse events compared to placebo, thyroid hormone and lithium. Common adverse events of quetiapine add-on therapy and quetiapine monotherapy included somnolence, fatigue, dry mouth, sedation, headache, dizziness and weight gain.

Quetiapine add-on therapy was associated with significantly higher in total medical costs, and outpatient services costs, but lower in pharmacy costs compared with brexpiprazole. Compared with aripiprazole, quetiapine and olanzapine were associated with higher all-cause hospitalization, all-cause emergency department visits, and total medical costs. In cost-effective analyses, quetiapine add-on therapy was found to be less cost-effective than aripiprazole.

Both guidelines recommend quetiapine as add-on therapy in patients who were insufficiently treated with antidepressants. Evidence on quetiapine misuse and abuse by patients with major depressive disorder were not identified.

Well-designed trials are needed that directly compare quetiapine add-on therapy or quetiapine monotherapy with competing interventions. Cost-effectiveness studies of quetiapine that are conducted with respect to the Canadian health care perspective are also warranted. Current findings may not be generalizable to the Canadian context, and they should be interpreted with caution given their limitations.