Xyzal temporarily relieves allergy symptoms such as sneezing; itchy, watery eyes; runny nose; and itchy nose and throat. Take Xyzal at nighttime; it will probably cause you to be drowsy but you'll awake symptom-free. There are 5 milligrams of levocetirizine dihydrochloride in a tablet; there are 35 tablets in a bottle – enough to get you through the worst of allergy season.