Staffy not well going on 3 weeks now?

can you help us my girlfriend has a staffy and is worrying like mad the staffy (taz) has been unwell for weeks and has been to the vet 3 times in two weeks he was on anti byotics for a week the was in today for blood tests and xray he was sent home with meds that might help or may not (panacur once daily for 3 days if that doesnt work then to try prednisolone 4 tabs once daily). but the thing is he keeps wanting to poo every time hes out some times 4 or 5 times in a row and the poo is geting reder by the day some times really blood looking we want to do the best we can for him but noting seems to work. we would be gratefull for any advice he was wormed an fled on the 2/6/11. yours andrew and sarah.