Dear Lisa,

You are absolutely right....your son is on a HUGE dose of medication!!!!  But, the good news is, I think I know what the problem is.  Let me try to explain:

If I understand you correctly, your son is getting a total of 20 mg. of HC/day, plus 1.0 mg of dexamethasone.  For treatment of CAH, dex is considered to be 80x more potent than HC.  This means your son is getting the equivalent of a total of 100 mg. of HC/day!  ( 20 mg + 80 mg).  I did a double-take when I first saw this and wanted to be sure that there were no decimal points out of whack with the size of the dex pill, but there doesn't seem to be.  From what I know, dex does come in 0.5 mg, not 0.05 mg, tablets.

I also took a quick look at your son's dose relative to his size, just to be sure that that number also looked abnormally high.  Using the upper estimates that you gave for height and weight ( I used 5'-8" and 180 #), I found his body mass to be 1.997 meter-squared (usually noted as m2).  Knowing your son's "m2" number allows you to compare the dose of medication that he's getting, to others with CAH.  At 100 mg. /day, your son's relative dose is 100 mg/1.997 m2 = 50.08 mg/m2/day.  This is about DOUBLE the amount of meds that most people, even SW patients, get.

Just as a double-check, I also looked at your son's dose, as if he were getting only dexamethasone.   Using the 80:1 conversion factor, your son's 20 mg. of HC would translate to 0.25 mg of dex.  Added to the 1.0, it means his total dex amount would be equivalent to 1.25 mg.  Therefore, his relative dex dose would then be 1.25 mg. /1.997 m2 = 0.62 mg/m2/day.  That is also more than DOUBLE the usual amount dosed for dex. 

I am almost positive that your son is on such a large dose because an equivalency error was made when he was put on the dexamethasone.....in fact, I would bet on it.  Believe it or not, the exact same thing happened with my son!  It is a very common mistake to use a 40:1 (rather than the afore-mentioned 80:1) conversion factor when trying to equate the potency of dex to HC.  In using 40:1, though, when converting from HC to Dex, you will inadvertently end up with DOUBLE the amount of medication---grossly over-suppressing the patient---as appears to be happening with your son.  When converting from Dex to HC, the opposite will happen, i.e. you will inadvertently end up with HALF the amount of medication, grossly under-suppressing the patient.  This second scenario was actually what happened with my son.

I'm sure you must be thinking that such a seemingly simple error could not be made by someone like Dr. New.  Unfortunately, it can....believe it or not, we were also at Cornell when this happened to us. If you are interested (and I suspect you will be), I have the name of another doctor for you, who is much more experienced in treating patients with dex.  You can email me, by clicking on my name in blue, if you'd like more information.  At any rate, the good news is that, if this turns out to be the problem with your son, it can be fixed!