American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the main action of bupropion in treating depression?

1. Serotonin reuptake inhibition

2. Dopamine and norepinephrine reuptake inhibition

3. Enhancing GABA activity

4. Increasing serotonin levels

The correct answer is: Dopamine and norepinephrine reuptake inhibition

Bupropion primarily acts as a norepinephrine and dopamine reuptake inhibitor. This means that it increases the levels of these neurotransmitters in the synaptic cleft by preventing their reabsorption back into the presynaptic neuron. This mechanism enhances neurotransmission and contributes to its antidepressant effects, making bupropion effective in the treatment of depression, as well as in addressing other conditions such as seasonal affective disorder and smoking cessation. The focus on norepinephrine and dopamine distinguishes bupropion from many traditional antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), which primarily target serotonin. By impacting these particular neurotransmitters, bupropion can have a unique profile, including a lower risk of sexual side effects and weight gain compared to other antidepressants. This broad message about its mechanism of action helps clarify its therapeutic role in depression management.