how long does prednisone last
18 Feb 2010. hi. the half life is roughly 4 hours. The prednisone should be tapered slowly and never stopped abruptly if you have been on it for over 2 weeks and were are a high dose. if you took it for 2-3 days you should be fine. The higher the dose and the longer you are on the drug the slower the taper. The drug itself should be out of your body less than 24 hours but flair ups can result if not tapered. Hope this helps. The elimination half life of prednisone is around 3 to 4 hours. This is the time it takes for your body to reduce the plasma levels by half. It usually takes around 5.5 half lives for a drug to be completely eliminated from your system.