Once kidney disease occurs, continued use of the problem drug makes it worse. Nonprescription pain medicines should not be used without your doctorâs permission if you know you have low kidney function. Also, even if your kidney function is good, longâterm use with high doses of these pain drugs may harm the kidneys. Kidney damage happens because high doses of the drugs have a harmful effect on kidney tissue and structures. These drugs can also reduce the blood flow to the kidney.