If you read the indications and contraindications for Lexapro , you will note that this
SSRI can--rarely--cause either high OR low blood pressure, as well as many other side effects. SSRIs that are better known for causing hypertension are Buproprion (Wellbutrin, Zyban), Venlafaxine (Effexor), and Phenelzine (Nardil):
http://highbloodpressure.about.com/od/lifeafterdiagnosis/a/antidepressants.