Hi Kate,  The other consideration is if your son is a salt waster, to much sodium could also raise his blood pressure.  My son who is a salt waster, is now 3.  His blood pressure at times has been high.  The endo never changed the amount of Florinef but did reduce the sodium intake and that lowered his blood pressure.  My son has been on the same amount of Florinef since he was born.  Hope this helps.

Kym P.