Mirtazapine for Major Depressive Disorder: Efficacy and Safety

Primary Considerations

The American College of Physicians recommends mirtazapine as an effective antidepressant for major depressive disorder, with comparable efficacy to other second-generation antidepressants, and a faster onset of action within 1-2 weeks 1

Mirtazapine demonstrates equivalent efficacy to SSRIs and other second-generation antidepressants for treating acute major depressive disorder, with no clinically significant differences in overall response rates 1, 2
The American Psychiatric Association notes that mirtazapine has a statistically significantly faster onset of action compared to citalopram, fluoxetine, paroxetine, and sertraline, with clinical improvement visible within the first 1-2 weeks of treatment 1, 3

The National Institute of Mental Health indicates that mirtazapine is not associated with sexual dysfunction, unlike SSRIs, which can have higher rates of sexual adverse events 4
The American Heart Association notes that mirtazapine shows no significant cardiovascular adverse effects even at doses 7-22 times the maximum recommended dose 5

The American Medical Association recommends beginning monitoring of therapeutic response and adverse effects within 1-2 weeks of initiation, and modifying treatment if inadequate response occurs within 6-8 weeks 2
The National Institute of Mental Health suggests continuing treatment for 4-9 months after satisfactory response in patients with first-episode major depressive disorder 2

Only 25% of patients become symptom-free after initial antidepressant trial, and 38% of patients do not achieve treatment response during 6-12 weeks of treatment with second-generation antidepressants 1, 3, 5
When initial therapy fails, switching to alternative medications, including mirtazapine, results in 1 in 4 patients becoming symptom-free 1