Hi drpdhmr,
The max dosage for Pred is 1 mg/kg of weight, you should be about half that dosage?
Normally the dosage is slowly increased to that maximum or until an improvement is noted. An immunosuppressant is also prescribed to be able to later reduce Pred intake, because the immunosuppressant are rather slow to kick in.
Some precautions are to be taken with Pred intake to minimize the side effects which are probable, such as weight increase, loss of potassium, risk of osteoporosis, glaucoma, etc...I suppose you were informed of all this, if not maybe you should look to another neuro more competent with MG...
Take care,
Maurice.