Effexor tablets are a prescription medication that physicians generally use to treat depression, although the extended-release version, Effexor XR, is also used to treat generalized anxiety disorder and social anxiety disorder. As is the case with a number of prescription anti-depression medications, Effexor has been shown to increase the risk of developing serotonin syndrome when taken along with certain migraine medications, i.e. triptans. Serotonin syndrome is a very serious medical condition that can result in coma or even death. Likewise, the U.S. Food and Drug Administration (FDA) included Effexor as one of many antidepressants that required a change in labeling to warn of the increased risks of suicidal thoughts and behavior that might result from taking the drug. Finally, Effexor can result in other serious side effects, particularly when taking in conjunction with certain other medications, such as high blood pressure, rapid heartbeat, bleeding problems, mania, and seizures, among others.