... for 4 days. I'm going into my 5th day of being on these and my moods are very unstable to the point that I feel I need to stop these immediately. I'm assuming from what I've read that I will still have side effects even though I've only been on them for a short time. I was on methyl prednisone before and had the same response and I told the doctor but he said that even though they were the same class of medication they were different. But obviously my body doesn't think so. I'm not sure if my hypothyroidism is playing a part in this because I know the medicine effects that as well. I was put on it to decrease inflammation (tennis elbow) Thanks!!