Blood in Urine This is usually a sign of a bladder or urinary tract infection. Prompt veterinary diagnosis and treatment is essential.   Recommended treatment: • Amoxicillin - 22mg/kg twice per day or • Trimethoprim Sulfa (Tribrissen) - 15mg/kg to 30mg/kg twice per day To link to this page: http://www.raisinrats.com/medical/bloodurine.html