Feels like I'm not emptying bladder. A week ago I had what I thought was a UTI but drank cranberry juice and was gone the next day. Can it be UTI rela (carisoprodol)?

Maybe. May be related to the UTI, but not emptying bladder may be more complicated than just a UTI. You should probably see your doc to make sure the bladder is emptying and get to the bottom of your problem - maybe this was not a UTI to begin with. Checking bladder volumes is a very simple and non invasive test.