Lexapro^® (escitalopram oxalate) is a prescription medicine that is used to treat depression and generalized anxiety disorder. The drug is a selective serotonin reuptake inhibitor (SSRI), which works by affecting the levels of a certain brain chemical (serotonin). Lexapro comes in tablet and liquid form and is usually taken once daily. Some of the common side effects seen with this drug include nausea, insomnia, and headaches. There is currently no generic version of Lexapro available.