text: It is safe to take 20mg of Zyrtec (cetirizine) daily? I take it in the morning but 12 hrs later I am suffering. If I don't take another one at night I dont sleep.
target: I am not able to sleep. I usually take 20 mg Zyretc (Cetrizine)  in the morning. Can I take another dose after 12 hours for sleeping? 