allergies
"I have chronic sinus allergies and my ENT prescribed Singulair and Allegra 180 mg one tab each per day. These worked fine for me, but my Doctor then asked me to try Xyzal instead of the Allegra, I've been using this new combination for about a month or so, but for me, the Allegra may be more effective, and I don't get the "drowsies" from it as I get with Xyzal. I then did something stupid, I tried being my own doctor, and took (2) Xyzal tabs with my usual 20mg of Singulair. The result being INCREASED histamine and drowsiness... so folks, the moral here is; Don't play Doctor,... abide by your Doctor's instructions... he/she knows best."