My first time on Solumedrol (4 years ago), it took quite a while for me to regain the feeling in my leg (which is why I was on it solumedrol in the first place). I expected it to work immediately and was disappointed that it didn't. Last summer, I had another exacerbation and the solumedrol worked almost immediately. In 2009, my MRI showed an emerging lesion, and in 2012, no new lesions. I don't know if that had anything to do with it - maybe my 2012 exacerbation wasn't as severe as 2009?