My endo told me to double the normal dosage, my son takes 2.5 mg 5:00 a.m so I would give 5.0 mg, 2.5 mg 1:00 p.m so I would give 5.0 mg, and 5.0 mg at 9:00 p.m so I would give 10.0 mg. Remember not to double the flourinef if your child takes flourinef. Hope your son feels better soon.