Venlafaxine is an antidepressant used to treat mental health conditions like depression, generalized anxiety disorder, social anxiety disorder, and panic disorder. It comes in two forms: extended-release, which is taken once a day, and immediate-release, which is taken in split doses throughout the day. This medication can interact with many things, including other medications and alcohol. Possible side effects can include nausea, weight changes, and sexual problems. It can also cause withdrawal symptoms if you stop taking it suddenly.