Which of the following medications is classified as an SSRI?

Fluoxetine is classified as a selective serotonin reuptake inhibitor (SSRI), which is a class of medications commonly used to treat depression and other mood disorders. SSRIs work by selectively inhibiting the reuptake of serotonin in the brain, leading to an increase in serotonin levels in the synaptic cleft. This increase is associated with improved mood and emotional regulation.

Fluoxetine specifically is one of the first SSRIs to be developed and is frequently prescribed due to its efficacy and relatively favorable side effect profile. By enhancing serotonin activity, fluoxetine helps alleviate the symptoms of depression and anxiety.

Other medications mentioned, such as Duloxetine and Venlafaxine, belong to a different class known as serotonin-norepinephrine reuptake inhibitors (SNRIs), which affect both serotonin and norepinephrine levels. Bupropion, on the other hand, is a norepinephrine-dopamine reuptake inhibitor (NDRI) and does not primarily act on serotonin. Thus, Fluoxetine distinctly fits the classification of an SSRI, making it the correct answer.