Hello, I went through your query, losartan is used to treat hypertension, helps to protect kidney in diabetes, it also helps in proteinuria. It doesn't cause any kidney problems or raise in creatine. Your raise in creatine levels could be due to underlying renal condition (may be cause of proteinuria). Please talk to your doctor regarding this. In rare cases, losartan can cause a condition that results in the breakdown of skeletal muscle tissue, which in turn leading to kidney failure. Consult your doctor at the earliest if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.