Final answer:
Bupropion (Wellbutrin) acts primarily as a dopamine reuptake inhibitor, increasing the levels of dopamine and norepinephrine in the synaptic cleft.
Step-by-step explanation:
The mechanism of action of bupropion (Wellbutrin) is as a dopamine reuptake inhibitor. This drug functions by preventing the reuptake of dopamine, as well as norepinephrine, into the presynaptic neuron, thereby increasing the amount of neurotransmitter present in the synaptic cleft. Unlike selective serotonin reuptake inhibitors (SSRIs) like Prozac, which specifically targets serotonin, bupropion affects both dopamine and norepinephrine, but its effects on serotonin are minimal, making it distinct among antidepressants.