Venlafaxine is used to treat depression and also sometimes is used to treat hot flashes in women who have experienced menopause or who are taking medication to treat breast cancer. Venlafaxine is in a class of medications called selective serotonin and norepinephrine reuptake inhibitors. It works by increasing the amounts of serotonin and norepinephrine in the brain. Venlafaxine comes as a tablet or extended-release capsule to take by mouth. Venlafaxine has been studied as an intervention for hot flashes, sleep-wake disturbances, peripheral neuropathy, and fatigue in patients with cancer.