I. Overview The pharmacological treatment of hyperglycemia is mostly based on the two main pathophysiological changes that lead to the increase of blood glucose in humans – insulin resistance and impaired insulin secretion. Oral hypoglycemic drugs can be divided into proinsulin secretagogues (sulfonylureas, glinides, DPP-4 inhibitors) and non-proinsulin secretagogues (biguanides, TZDs, α-glucosidase inhibitors) according to their effects. Sulfonylureas and glinides directly stimulate insulin secretion; DPP-4 inhibitors increase insulin secretion by decreasing the breakdown of GLP-1 in vivo and increasing the concentration of GLP-1 in vivo; the main pharmacological effect of biguanides is to reduce hepatic glucose output; the main pharmacological effect of TZDs is to improve insulin resistance; the main pharmacological effect of α-glucosidase inhibitors is to delay the The main pharmacological effect of α-glucosidase inhibitors is to delay the digestion and absorption of carbohydrates in the intestine. Medical nutrition therapy and exercise therapy for diabetes are the basic measures to control hyperglycemia in type 2 diabetes. Medication including oral medication should be used promptly when diet and exercise do not bring blood glucose control up to standard. Type 2 diabetes is a progressive disease. In the natural course of type 2 diabetes, the function of pancreatic β-cells declines gradually with the prolongation of the disease, and the degree of insulin resistance does not change much. Therefore, as the course of type 2 diabetes progresses, the dependence on exogenous means of glycemic control gradually increases. Combination therapy between oral drugs is often required in clinical practice. Second, metformin At present, the main clinical use of metformin drugs is metformin hydrochloride. The main pharmacological effect of metformin is to reduce blood sugar by reducing hepatic glucose output and improving peripheral insulin resistance. Many national and international organizations have developed diabetes guidelines that recommend metformin as the first-line drug and the base drug in combination for the control of hyperglycemia in patients with type 2 diabetes. Clinical trials have shown that metformin can reduce HbA1c by 1% to 2% and can lead to weight loss. Metformin has also been shown to reduce cardiovascular events and death in obese patients with type 2 diabetes in the UKPDS trial. Metformin alone does not cause hypoglycemia, but the risk of hypoglycemia can be increased when metformin is combined with insulinotropic agents. The main side effect of metformin is gastrointestinal reactions. Starting with a small dose and gradually increasing it is an effective way to reduce adverse reactions. A rare serious side effect of metformin is the induction of lactic acidosis. Contraindications to metformin: Metformin is contraindicated in patients with renal insufficiency (blood creatinine level >133μmol/L in men and >124μmol/L in women or glomerular filtration rate <60ml/min), hepatic insufficiency, severe infection, hypoxia or major surgery. Metformin should be temporarily discontinued when iodinated contrast agent is used for contrast examination. Sulfonylureas are insulin-producing agents, and their main pharmacological effect is to stimulate insulin secretion by pancreatic islets. The main pharmacological effect is to lower blood glucose by stimulating insulin secretion from pancreatic cells and increasing insulin level in the body. Clinical trials have shown that sulfonylureas can reduce HbA1c by 1% to 2%, and they are the main drugs recommended in the diabetes guidelines formulated by many countries and international organizations for controlling high blood sugar in patients with type 2 diabetes. The main sulfonylureas currently available in China are glibenclamide, glimepiride, gliclazide, glipizide and glipizide. Sulfonylureas can lead to hypoglycemia if used improperly, especially in elderly patients and those with hepatic and renal insufficiency; sulfonylureas can also lead to weight gain. In patients with mild renal insufficiency, gliptone is appropriate. When patients have poor compliance, it is recommended to take sulfonylureas that are taken only once a day. Sulforaphane is a fixed-dose combination containing gliphenylurea and various herbal ingredients. IV. Thiazolidinediones Thiazolidinediones (TZDs) lower blood sugar mainly by increasing the sensitivity of target cells to insulin action. At present, the TZDs marketed in China mainly include rosiglitazone maleate and pioglitazone hydrochloride. Clinical trials have shown that TZDs can reduce HbA1c by 1.0% to 1.5%. TZDs do not cause hypoglycemia when used alone, but can increase the risk of hypoglycemia when used in combination with insulin or proinsulin secretagogues. Weight gain and edema are common side effects of TZDs, and this side effect is more pronounced when used in combination with insulin. The use of thiazolidinediones is also associated with an increased risk of fracture and heart failure. This class of drugs should be contraindicated in patients with heart failure (NYHA cardiac class II or higher), active liver disease or transaminases elevated more than 2.5 times the upper limit of normal, and a history of severe osteoporosis and fractures. The use of rosiglitazone is strictly limited in China because of the controversial safety issues. For patients with diabetes who have not used rosiglitazone and its combination, rosiglitazone and its combination should be considered only when other hypoglycemic agents are not available or when the goal of glycemic control cannot be achieved with other hypoglycemic agents. For those who are already using rosiglitazone and its combination, the risk of cardiovascular disease should be evaluated and the decision to continue the medication should be made after weighing the pros and cons of using the medication. V. Glinides are non-sulfonylurea insulin stimulants, and the ones marketed in China include Repaglinide, Naglinide and Miglinide. This kind of drugs mainly through the stimulation of insulin early secretion and reduce postprandial blood sugar, has the characteristics of fast absorption, fast onset and short duration of action, can reduce HbA1c0.3% ~ 1.5%. These drugs need to be taken immediately before meals, and can be used alone or in combination with other hypoglycemic drugs (except sulfonylureas). The common side effects of glinides are hypoglycemia and weight gain, but the risk and extent of hypoglycemia is less than that of sulfonylureas. VI. α-glucosidase inhibitors α-glucosidase inhibitors lower postprandial blood glucose by inhibiting the absorption of carbohydrates in the upper part of the small intestine. It is suitable for patients with carbohydrates as the main food component and elevated postprandial blood glucose. The α-glucosidase inhibitors marketed in China include acarbose, voglibose and miglitol. α-glucosidase inhibitors can reduce HbA1c by 0.5% to 0.8% without increasing body weight and have a tendency to reduce body weight, and can be combined with sulfonylureas, biguanides, TZDs or insulin. The common adverse reactions of α-glucosidase inhibitors are gastrointestinal reactions such as abdominal distention and exhaustion. Starting with a small dose and gradually increasing it is an effective way to reduce adverse reactions. Hypoglycemia usually does not occur when this class of drugs is taken alone; if hypoglycemia occurs in patients who combine with α-glucosidase inhibitors, glucose or honey is required for treatment, while consumption of sucrose or starchy food is poorly effective in correcting hypoglycemia. Seven, dipeptidyl peptidase-4 (DPP-4) inhibitors DPP-4 inhibitors reduce the inactivation of GLP-1 in vivo by inhibiting DPP-4 and increase the level of GLP-1 in vivo. GLP-1 enhances insulin secretion and inhibits glucagon secretion in a glucose concentration-dependent manner. The DPP-4 inhibitors currently available in China are sitagliptin, saxagliptin and vildagliptin. Clinical trials including Chinese patients with type 2 diabetes have shown that selegiline can reduce HbA1c by 1.0%. DPP-4 inhibitors alone did not increase the risk of hypoglycemia and did not increase body weight. Care should be taken to reduce the dose of the drug according to the drug's instructions when using it in patients with renal insufficiency.