text: how long does it take for the side effects of lexapro to where off? i only take the 10s for 4 days and i feel a little sick for a couple of hours after i take em and really hot like i'm gonna burn up. either you are allergic to the drug, or it is reacting negatively with some other drug you are taking, so tell your doctor and ask his or her advice about what modifications you should make with the dosage.