Effexor Addiction: Side Effects, Detox, Withdrawal, and Treatment Table of Contents What is Effexor? Effexor is the brand name for the drug venlafaxine, which is an antidepressant drug and a serotonin-norepinephrine reuptake inhibitor (SNRI). Effexor is one of the most popular antidepressants in the U.S. and it is most often prescribed to treat depression, anxiety, … Continue reading Effexor