If the patient is diagnosed with diabetic nephropathy, and the creatinine and urea nitrogen levels are normal, oral hypoglycemic drugs, such as sulfonylureas, metformin, and glycosidase inhibitors can be taken orally, and insulin is also a better choice. If patients with diabetic nephropathy have combined renal insufficiency and creatinine levels are significantly elevated, the application of many glucose-lowering drugs is restricted. The oral glucose-lowering drug of choice is glipizide among sulfonylureas, because the drug is excreted through the kidneys very little, so it is the only glucose-lowering drug among sulfonylureas that can be used in patients with renal insufficiency. The best choice is insulin treatment, because insulin is safer for patients with renal insufficiency and has a better effect on lowering sugar.