People who have depression or generalized anxiety disorder may benefit from using Lexapro^® (escitalopram oxalate). This prescription medication works by increasing the amount of a certain chemical in the brain known as serotonin. Most people tolerate Lexapro well; and even when side effects occur, they are usually minor and can easily be treated by you or your healthcare provider. Some side effects of Lexapro include insomnia, nausea, and headaches. Lexapro comes in the form of a tablet or a liquid, and it is usually taken once daily.