Final answer:
Venlafaxine (Effexor) is a second-generation antidepressant that acts as a serotonin-norepinephrine reuptake inhibitor (SNRI), increasing the levels of serotonin and norepinephrine in the brain.
Step-by-step explanation:
Venlafaxine (Effexor) is classified as a second-generation antidepressant. Second-generation antidepressants, also known as atypical antidepressants, work by altering the levels of neurotransmitters in the brain. Venlafaxine specifically acts as a serotonin-norepinephrine reuptake inhibitor (SNRI), which means it increases the levels of serotonin and norepinephrine in the brain by blocking their reuptake into neurons.