constipated kitty now has diahrea

Question
my kitty is 3 yrs old has had surgey for bladder stones8 months ago is on urinary diet,he was doing fine,i changed his food a few months ago to a urinary diet just a different brand not at first after a month to 6 weeks  i noticed he had not been pooing3 days would go by then he would go after i placed him in the litter box constipated for a month he began acting funny running around pooping on the rug peeing on the rug like last he was sick,the vet said he had a bacterial infaction in his intestines he sumised from not going so long inbetween,he said he wasnt blocked at the time of vist and gaave him antibiotics now he is pooing diahrea all over we confined him but its a night mare he wants his freedom but i cant let him go everywhere.doc says he shouldnt get diahrea from meds but he did the last time he had them .what can i give him to stop the pooooooooos,and in your experience does antibiotics cause the pooooooos  help!!!!     linda

Answer
Hi Linda-

While this question is in the wrong section (You posted in Dogs) I believe I can be of some assistance.

Try Immodium. 0.1 mg/pound by mouth every 8 hours, but not for more then 2 days.

If it continues for more then 2 days, or he begins vomiting, he needs to go to the vet. I can't tell you if the antibiotic causes loose stools because you didn't mention which antibiotic it is. Did your vet do a fecal exam? What food did you switch him to?