When my daughter has a fever I double each dose while she has the fever, If she has a low fever and is acting weird (lethargic) I double, for high fevers above 100.5 I triple. If she has a fever at each medicine time I give extra, Good luck- You should talk to your endo and see what they say, b/c every kid is different. After a few fevers and a few calls to the endo you will have it all figured out on your own, I did. Noone knows your child better than you so use your best judgement. Our endo said if ever in question it is better to have more than not enough. Good luck-Michelle