According to DrugDetox.org, the half-life of Lexapro is 27 to 32 hours. Someone who takes 10 milligrams metabolizes it in about four to five days. Everyone is different, and there may be circumstances that could affect the time it takes for Lexapro to completely leave an individual's system.
Although Lexapro can leave the body within a relatively short time frame, a person who has been taking it for a long period of time may experience withdrawal. According to WebMD, symptoms of withdrawal include dizziness, depression, anxiety, nausea, fatigue, flu-like symptoms or trouble sleeping and can take several weeks to subside. To avoid withdrawal, it is best to gradually taper off the dosage over a long period of time.