Effexor XR (venlafaxine) is a prescription capsule that’s used to treat depression, anxiety, and panic disorder. Learn about side effects, dosage, and more. Effexor XR is a serotonin and norepinephrine reuptake inhibitor (SNRI) used to treat depression, generalized and social anxiety disorder, and panic disorder. Taking EFFEXOR XR can cause a potentially life-threatening problem called serotonin syndrome. The risk of developing serotonin syndrome is increased when EFFEXOR XR is taken with certain other medicines. Effexor XR is an extended-release capsule for once-a-day oral administration that contains venlafaxine hydrochloride, a serotonin and norepinephrine reuptake inhibitor (SNRI). Venlafaxine is used to treat depression. It is also used to treat general anxiety disorder, social anxiety disorder, and panic disorder. Venlafaxine belongs to a group of medicines known as serotonin and norepinephrine reuptake inhibitors (SNRI). Effexor XR (venlafaxine) is used to treat major depressive disorder, anxiety, and panic disorder. Includes Effexor XR side effects, interactions and indications. Review the most frequently asked questions for EFFEXOR XR® (venlafaxine HCl) and talk to your doctor. Please see the Med Guide & Full Prescribing Info, including Boxed WARNING. Effexor XR: side effects, dosage, interactions, FAQs, reviews. Used for: anxiety, autism, depression, generalized anxiety disorder, major depressive disorder, panic disorder, and more. Find patient medical information for Venlafaxine (Effexor) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Venlafaxine, sold under the brand name Effexor among others, is an antidepressant medication of the serotonin–norepinephrine reuptake inhibitor (SNRI) class. [5][9] It is used to treat major depressive disorder, generalized anxiety disorder, panic disorder, and social anxiety disorder. [9].