What is Effexor? Effexor is Wyeth Pharmaceuticals’ brand name for venlafaxine, a serotonin-norepinephrine reuptake inhibitor (SNRI) used as an antidepressant in the treatment of clinical depression, generalized anxiety disorder and certain combination depression and anxiety disorders. How does Effexor work? Effexor works by blocking the reuptake of serotonin and norepinephrine in the synaptic gap and [...]