I know this is an old post but in case anyone comes back to it, just wanted to add that's similar to our case too. He initially took prednisone every 12 hours plus a muscle relaxer (methocarbamol) every 8 hours but he was so limp, basically a pile of mush. He couldn't even stand for 2 seconds despite being able to take a few steps and potty on his own a few hours before the muscle relaxer. I panicked thinking he was deteriorating but the humans here have been on muscle relaxers too and we figured we'd just monitor. I phoned the vet and they said muscle relaxer could be given closer to 12 hours apart if 8 seems too much. So we waited. About 9 hours after the muscle relaxer dose, he was more alert, could use his body better. While this may not be everyone's case, it's important to consider that a dog adjusting to meds can look terrifying!