Effexor^® (venlafaxine hydrochloride), part of a group of medications called serotonin-norepinephrine reuptake inhibitors (SNRIs), is commonly used to treat depression in adults. This prescription medication works by affecting certain brain chemicals. Although most people tolerate Effexor well, this medication is not suitable for everyone. A few of the conditions you should let your healthcare provider know about before taking the medication include bipolar disorder, epilepsy, and liver disease.