This medicine include nausea, vomiting, diarrhea, upset stomach, loss of appetite, dizziness, drowsiness, trouble sleeping. If left untreated, can cause major problems in your life. Lexapro is an antidepressant in a group of drugs called selective serotonin reuptake inhibitor. Escitalopram is a selective serotonin reuptake inhibitor used to treat anxiety and major depressive disorder.