Which medication is an example of a selective norepinephrine reuptake inhibitor (NRI)?

Reboxetine is indeed an example of a selective norepinephrine reuptake inhibitor (NRI). It works by selectively inhibiting the reuptake of norepinephrine in the synaptic cleft, which increases the concentration of norepinephrine available to bind to its receptors, thereby enhancing norepinephrine transmission in the brain. This mechanism is thought to contribute to its antidepressant effects, particularly in the treatment of major depressive disorder.

Other medications mentioned in the options have different primary mechanisms of action. Venlafaxine and desvenlafaxine primarily act as serotonin-norepinephrine reuptake inhibitors (SNRIs), as they inhibit the reuptake of both serotonin and norepinephrine, not selectively targeting norepinephrine alone. Fluoxetine, on the other hand, is a selective serotonin reuptake inhibitor (SSRI), primarily affecting serotonin levels without a notable effect on norepinephrine reuptake. This distinction is critical in understanding the pharmacological profiles and the specific indications of these medications in treating various types of depression and related disorders.