Which medication is a monoamine-oxidase inhibitor (MAOI)?

Marplan, or isocarboxazid, is indeed classified as a monoamine oxidase inhibitor (MAOI). MAOIs work by inhibiting the activity of the enzyme monoamine oxidase, which is responsible for breaking down neurotransmitters such as serotonin, norepinephrine, and dopamine in the brain. By decreasing the breakdown of these neurotransmitters, MAOIs can increase their availability, potentially improving mood and alleviating symptoms of depression.

This mechanism makes MAOIs effective for treating certain types of depression, particularly atypical depression and treatment-resistant depression. However, they come with dietary restrictions and potential interactions with other medications, which makes their use more complex compared to other classes of antidepressants.

The other medications listed – Tofranil (imipramine), Cymbalta (duloxetine), and Wellbutrin (bupropion) – belong to different classes of antidepressants: tricyclic antidepressants (imipramine), serotonin-norepinephrine reuptake inhibitors (duloxetine), and norepinephrine-dopamine reuptake inhibitors (bupropion), respectively. Each of these has a different mechanism of action and side effect profile that distinguishes them from MAOIs.