Main Page | See live article | Alphabetical index Effexor is the tradename for the antidepressant venlafaxine and acts on both the levels of serotonin and norepinephrine. Effexor is a popular antidepressant, however it is known for severe withdrawal effects such as dizziness,lightheadedness, and depression. Therefore, if you do stop taking it, you should stop slowly. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.