Decadron Shot

Hi,
    How long does a combination steroid shot: 1 mg decadron, 80 mg dexamethasone, 1% sodium phosphate stay in your system?  I received one 10 days ago.  I had initial flushing and facial burning, along with stuffy ears and sinuses. Most of this has abated now.  I still feel a little weak and my appetite is poor. I did not have these feeling before the shot.  I am being treated for a muscle strain. Also will my Estraderm patch interfere with clearance of this drug from my body?

[Alison L, RPh]

The onset and duration of action of dexamethasone injection ranges from 2 days to 3 weeks and is dependent on whether the drug is administered by intra-articular or IM injection and by the extent of the local blood supply.  Dexamethasone may decrease the clinical efficacy of estrogens.