Your poor little poppet. As BlackCat says, for some kids it seriously knocks them out but others go a bit hypo. My 5 year old had some earlier this year for a very bad eczema thing (geez, I sound like I drug my kids all the time!), and she didn't sleep for aaaaaaaages. Not much you can do once she's had it of course, but just be prepared that you might need some late night tv viewing ;-)

Its so hard when there almost always seems to be a big downside to any kind of medication you give your kids.