Effexor^® (venlafaxine hydrochloride) is a type of serotonin-norepinephrine reuptake inhibitor (SNRI) that is approved to treat depression in adults. This prescription medication comes in the form of a tablet that is taken two or three times a day. Effexor may not be suitable for everyone, so let your healthcare provider know of any medical conditions you have or any medications you are taking. Potential side effects of Effexor may include nausea, insomnia, and dizziness.