Hello,, here are side effects of levocetirizine, More common-Headache muscle ache sleepiness or unusual drowsiness sore throat stuffy or runny nose. Less common-Body aches or pain, congestion, diarrhea, dryness or soreness of the throat ache, earache, hoarseness, redness , or swelling in the ear, tender , swollen glands in the neck, voice changes. It's not clear why you are taking LCZ and for how long,,, need not to worry for headache caused by LCZ, if troubling more,, try stopping LCZ,, if headache persists even after stopping thus tablet consult general physician.