Does diabetic medication affect the kidneys?

Yes: Almost all medications of any kind can affect either the liver or kidneys in large doses and/or long-term use. Several diabetic medications do affect the kidneys, the most notable being metformin (glucophage). That is not to say these drugs should not be used for diabetes or you cannot use them if you have kidney disease - simply that frequent monitoring of your kidney function is necessary.

Dose adjustment: A confusing situation. Diabetes medications don't damage the kidneys but instead it is a situation of dose adjustment. When people have kidney disease, most often from diabetes, high blood pressure, and age, it is necessary to either lower medication doses or in some cases stop them all together as the kidneys excrete the medications from the body and a lower dose is needed with reduced function.