When my daughter first started attending daycare and I went to work she got very very sick for about 3 months straight. Nothing the provider could have done, it was different things each time but one worse than the other. At one point she was dehydrated badly and dry heaving so Emerg we went. They asked what I was giving her and said Tylenol, the Dr sid "Tylenol doesn't do sh*t .... sorry to say" He then gave her a dose of advil about 45min after her fever which lasted 5 hours of 104.8 went down to 101....We had tried everything, cool baths, no clothes, cool drinks, damp cloth...nothing worked. Advil did!
So I have no faith in Tylenol's working abilities it never worked for me growing up....I had juvenile arthritis and now as an adult really bad joint pains and Tylenol never helped with the pain. I must have been 16/17 when I first heard of Advil and it was like a miracle! I only use Advil for myself and my daughter now.
*Just my own personal feelings* :P
Plus 8hr of relief vs 4hrs = my baby get to sleep most of the night without feeling crappy!