Prednisone side effects
The oncologist put Blaise on Prednisone once it became clear the chemo wasn't working. He had her on 20mg once daily, she was only 55lb.
I really felt for her, she was SO hungry all the time and drank vast amounts of water. I was thinking about weaning her off it but I did a little investigating and decided the benefits outweighed the negatives, but of ccourse in her case it was essentially palliative care and the prednisone apparently has, as well as chemo like effects, some pain relieving benefits.
The fast breathing seems to be a side effect too. I didn't notice any personality changes. She did become less active etc, but that happened over a period of time and was to be expected with all the tumours growing everywhere.
I did find that after a while the side effects of the prednisone tended to reduce, but that would have been after about 6 weeks or so.
Garvin was put on quite a high dose for allergies a few years ago and he had terrible problems with peeing in the house and got so hungry he busted into the bin and ate everything in it (off to the vets to have his stomach 'evacuated' - no fun at all). Luckily that was only for a short time though. I did notice a personality change with Garvin, so I imagine it is related to dosage.
They will probably reduce his dosage if it's so unpleasant for him.
Good luck with it.