It can take a few days, but if you're not experiencing full relief and are on a lower dose, I'd consider talking to your doctor and asking about increasing the dose. I know you mentioned your dose before, but can't remember what you started on... I think my dad started on 20 mg and ultimately had to go to 30 mg. The goal is to quash the inflammation (if you're positive for inflammatory markers) and almost all the pain, be stable for a while and then start a taper that hopefully keeps you mostly stable. If those dose isn't high enough, it may be harder for you to get to that point.

This is where my dad's rheumatologist says sorting it out can be "more of an art than a science." I think she means it's more like following what your body is saying... And then I tell her: "But that's the problem; I don't always understand what it's telling me to do..." >_<

There are a few people here in the group who've found splitting the dose helps them. That didn't work for my dad, because the prednisone really affected his sleep, so he has to take it all in the morning.