Best advice I can give, having work in a pediatric ER for 3 years.... if your child starts to have fever (greater than 100.4F oral or rectal) start to give Tylenol and ibuprofen every other 3 hours. For example: noon temp 102F. Give Tylenol, 3:00pm give ibuprofen, 6:00pm give Tylenol, 9:00pm give ibuprofen. What this does is prevent the temp from ever being allowed to spike. Tylenol can wear off at just over the 3 hour mark so it does still give about an hour where his temp may be able to rise too quickly causing the seizure. ibuprofen is the same way... it's to be given every 6 hours but temps can start to spike at about the 5th hour, again allowing for seizure. By alternating meds every 3 hours, you're avoiding an spike in temp and you're also staying safe with dosing as each dose of the same med will be 6 hours apart. Ibuprofen and Tylenol work completely differently and so giving them 3 hours apart will in no way cause harm to him. Hope this helps. Just because he has had 1 febrile seizure does not mean he has a seizure disorder (which I assume you know by now), nor does it mean that he will ever have a seizure again. He could, but I have never seen this Tyleno/ibuprofen method not work. Parents love it because their kid is less cranky and kida love it because they don't feel as bad. Hope this helps... just a suggestion.