The dose you gave to your child (500 mg of ibuprofen) is well within the dosing guidelines for an 11 year old weighing 100 pounds.

Below are the ibuprofen dosing guidelines for children:

  • 1 to 12 years of age: 50 mg/kg/day by mouth (Max: 3,200 mg/day)

So, in your case, your child weighs 100 pounds or 45.35 pounds. Per the dosing guidelines of 50 mg/kg/day, that amounts to a maximum dose of 2,267 mg per day. As ibuprofen is usually recommended to be given in 3 to 4 divided doses per day, 500 me per dose is within the acceptable range.