You are at the recommended
dosage for treating anxiety. 20 mg is the
dosage the manufacturer originally recommended for depression, so the first question is, why not up the dosage of the drug you're on first and see if that works? It would be the least bothersome thing to do for you, as since you've been on Lexapro for awhile anyway it's going to have all the problems of stopping it anyway. A second question would be, why add two drugs instead of just adding one?