What medication is commonly used as a second-line treatment for major depressive disorder?

In the treatment of major depressive disorder (MDD), selective serotonin reuptake inhibitors (SSRIs) are often the first-line option due to their favorable side effect profile and efficacy. When a patient does not respond sufficiently to SSRIs or cannot tolerate them, clinicians may consider second-line treatments.

Serotonin-norepinephrine reuptake inhibitors (SNRIs) are commonly utilized as a second-line therapy. They work by increasing the levels of both serotonin and norepinephrine in the brain, which can be beneficial for patients who have not responded to SSRIs. SNRIs may also be particularly effective in patients with more severe symptoms, co-existing anxiety disorders, or pain syndromes commonly associated with depression.

Tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) can also be options for treatment-resistant depression, but they are less frequently used as second-line treatments nowadays due to their side effect profiles and dietary restrictions associated with MAOIs. These factors contribute to SNRIs being a more commonly chosen second-line treatment in current clinical practice.