Will Prednisone and/or Amoxicillin cause urinary incontinence in dogs?

My dog was recently started on a combination of Prednisone and Amoxicillin by the vet. The vet think she was bitten by fire ants and she has mutliple sores on her head. She's been scratching so when I took her to the vet last night, that's what she got started on. She did fine last night, went outside late in the evening and when I woke up this morning, I saw she had peed in the floor! This is VERY unusual for her! I work 12 hours shifts and if I can't get anyone to take her out she will occionally have to stay by herself - she has never once peed in the house when I've worked 12 hours!!! She hasn't peed in the floor since she was a small puppy!! I don't know what's wrong with her....Help!