I don't have MG but I do have MS, and I've had to take high doses of oral cortisone on many occassions to treat the sympyoms of a flare up.

During an exacerbation my usual dose is 75mgs orally per day and when my symptoms ease off, my neuro gives me a regime to taper off.

What I've noticed about my moon face is that once my taper has completely finished (so I'm totally off the cortisone), it'll take the same amount of time for my round face to disappear as from when I started the medication ...... until that final dose in the taper.

For example, if I was taking the regulated dose of cortisone for a month and I had to taper down over a month.... then it would take 2 months for my face to return to it's usual shape. Does that make sense?

Strangely enough, when I'm given my cortisone by IV infusion, my neuro gives me 1000mgs per day over 3 days, and even though the dose is much higher..... it dosn't give me the moon face side effect. Must be something to do with the shorter infusion time.

I hope I haven't confused you now.