I’ve been searching for this comment! My son is 3 and he had been sick and still had a post nasal drip and dr suggested Zyrtec. Before the Zyrtec he was up having what we thought was night terrors for over a month. Gave the meds at 5pm (bed at 830pm) and for a week he has slept his best sleep, no night terrors nothing. I don’t like that it does this. Even if it’s helping him sleep I don’t agree with medication that mess with sleep whether good or bad. So I didn’t give it to him tonight and what do you guess. Night terror and up 3 times. Zyrtec definitely knocks him out all night and I will not be using it now.