Fluoxetine is the only selective serotonin uptake inhibitor (SSRI) that increases the extracellular levels of norepinephrine and dopamine in the prefrontal cortex.
Bupropionis a unique antidepressant as it is a dopamine reuptake inhibitor (DRI), which causes an increase in dopamine levels in the synapse. This has made it a popular choice for smoking cessation, and it is most commonly prescribed for this purpose. Norepinephrine and dopamine reuptake inhibitors (NDRIs) are a type of antidepressant used to treat depression.
NDRIs are newer than first-generation antidepressants, and bupropion was synthesized in 1966 by a group looking for new antidepressants that were chemically related to tricyclic antidepressants, but without significant sympathomimetic, cholinolytic, or monoamine oxidase inhibitory properties. NDRIs generally don't cause the side effects that may be common to other antidepressants, making them an attractive option. Bupropion is also used to treat attention deficit hyperactivity disorder (ADHD) in adults. While the risk of abuse is much lower than other drugs of abuse, there is still a chance that these drugs will be abused, which could increase the risk of seizures, heart problems, and other health issues.
The recommended dose for bupropion is 150 mg twice daily after one week and should be maintained for nine more weeks. NDRIs are included in a broader classification of atypical antidepressants, so called because they don't fit into any of the other classes of antidepressants. A dopamine reuptake inhibitor works by blocking the dopamine transporter and the norepinephrine transporter, thus increasing dopamine concentrations. The clinical efficacy of all antidepressants lags behind their pharmacological actions by a few weeks.
Increased dopamine levels in the synapse are thought to help mimic the reward associated with smoking, thus reducing some of the withdrawal symptoms associated with quitting smoking. In clinical trials, bupropion appears to have a lower propensity for sexual side effects compared to SSRIs and other serotonergic antidepressants.