Lexapro blocks the re-absorption of serotonin by the first nerve cell. Do have problems note that they are much less severe than they were on older anti-depressants. Do not take Escitalopram together with a monoamine oxidase inhibitor. This medication may cause dizziness or drowsiness. Lexapro blocks the re-absorption of serotonin by the first nerve cell. Lexapro is used to treat anxiety and major depressive disorder.