My 95 yr. old Father was diagnosed with a U.T.I. about a week ago, and sent home from the hospital with a prescription for Ciproflaxcin. He had a bad reaction to that, so he was prescribed Ampicillin. I have tried to administer the medications as directed, and he is still not feeling well. He has not had a bowel movement since last week either. I ve tried to encourage him to eat, however, his appetite is sparse. So, in lieu of solid food, I give him the Ensure liquid. Usually, antibiotics work within just a couple of days...so I m puzzled and very concerned. Any help is appreciated.