Venlafaxine XR is part of a class of drugs called serotonin-norepinephrine reuptake inhibitors, or SNRIs for short. SNRIs, such as venlafaxine XR, act on specific chemicals within the brain known as serotonin and norepinephrine. Serotonin and norepinephrine are two of several chemicals used to send messages from one nerve cell to another.
As a message travels down a nerve, it causes the end of the cell to release serotonin or norepinephrine. The serotonin or norepinephrine enters the gap between the first nerve cell and the one next to it. When enough serotonin or norepinephrine reaches the second nerve cell, it activates receptors on the cell and the message continues on its way. The first cell then quickly absorbs any serotonin or norepinephrine that remains in the gap between cells. This is called "reuptake."
Normally, this process works without any problems. But when the levels of serotonin or norepinephrine become unbalanced, it can cause a variety of conditions, including depression. Venlafaxine XR helps to block the reuptake of serotonin and norepinephrine so more remains in the space between the brain's nerve cells. This gives the serotonin and norepinephrine a better chance of activating the receptors on the next nerve cell.
Venlafaxine XR: Effects
There have been several studies looking at the effects of venlafaxine XR for a variety of conditions.
Venlafaxine XR for Depression
Studies have shown venlafaxine XR to be effective at treating depression in adults. In these studies, people taking venlafaxine XR had more improvement in their depression symptoms than people who did not take venlafaxine XR. Also, long-term studies showed that venlafaxine XR is also effective at preventing depression relapse.
Written by/reviewed by: Kristi Monson, PharmD;Arthur Schoenstadt, MD
Last reviewed by: KristiMonson, PharmD;
List of references (click here):
Effexor XR [package insert]. New York, NY: Pfizer Inc;2012 December.
Venlafaxine (Venlafaxine Hydrochloride) Tablet, Extended Release for Oral Use [package insert]. Wilmington, NC: Osmotica Pharmaceutical Corp.;2008 May.
Food and Drug Administration, Center for Drug Evaluation and Research. Electronic orange book: approved drug products with therapeutic equivalence evaluations. FDA Web site. Available at: http://www.fda.gov/cder/ob/. Accessed August 20, 2010.
Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 7th ed. Philadelphia (PA): Lippincott Williams & Wilkins;2005.
National Library of Medicine (US). Drugs and Lactation Database (LactMED). NLM Web site. Available at: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT. Accessed February 19, 2007.
eMedTV serves only as an informational resource. This site does not dispense medical advice or advice of any kind.
Site users seeking medical advice about their specific situation should consult with their own physician. Click