Discussion in 'Men's Health Forum' started by chemman, Apr 12, 2010. # 1 1 chemman Active Member. The stated half life for methylprednisolone is 18-26 hours. # 2 2 chemman Active Member. And I'm really wondering how long a medrol dose pack stays in the body from the last dose. # 3 3 hardasnails1973 Active Member. chemman said: ↑. # 4 4 chemman Active Member.