If you are on prednisone all the time, this can cause systemic effects which might include weight gain.  I know when I'm on this stuff I feel like I'm hungry all the time and tend to overeat.    One of the advantages of being on symbicort is it should allow you to need prednisone less often.  If you take your symbicort properly, and if you rinse and brush your teeth after each use, you should eliminate the risk of side effects.    While side effects from symbicort can happen, they are generally rare.  Hoarseness is one side effect of symbicort.  The best way to eliminate any side effect of this medicine is to rinse your mouth really well after each use.