In terms of safety, acarbose can delay the digestion and absorption of carbohydrates, prolong the retention time of carbohydrates in the colon, increase glycolysis, and common gastrointestinal reactions such as bloating and exhaust. Starting from a small dose, gradually increasing the dose can reduce the adverse reactions, and taking acarbose alone usually does not cause hypoglycemia. Individual patients, especially those who take acarbose in large doses, will have asymptomatic elevation of transaminase. It is suggested to monitor the changes of transaminase in the first 6- 12 months after taking acarbose, but this abnormality is transient and the liver enzyme value will return to normal after stopping taking acarbose. Acarbose only acts on the intestine and is hardly absorbed into the blood. Its bioavailability in vivo is extremely low, only 1%-2%. Acarbose and its degradation products can be quickly and completely excreted from urine after oral administration, with good safety.
Metformin belongs to biguanide oral hypoglycemic agents, and it is the first-line and preferred drug for the treatment of type 2 diabetes. Metformin mainly reduces blood sugar by reducing the output of glucose in liver, improving peripheral insulin resistance and inhibiting the absorption of glucose by small intestinal mucosa. Monotherapy can effectively reduce fasting blood glucose and postprandial blood glucose, and can also lose weight. It is also the basic drug in combination medication, and can be used in combination with other oral hypoglycemic drugs or insulin to further improve blood sugar control. In addition, metformin can also improve blood lipid profile, inhibit platelet aggregation, anticoagulation, inhibit fibroblast proliferation, improve the function of vascular endothelial cells, increase blood flow, have a clear cardiovascular protection effect, and can significantly reduce the risk of cardiovascular events.
In terms of safety, the common adverse reactions of metformin, such as diarrhea, nausea, vomiting, abdominal distension, indigestion, abdominal discomfort, fatigue, headache, etc., often occur at the initial stage of treatment, and most patients can tolerate them. With the extension of treatment time, the above adverse reactions can basically disappear. Starting from a small dose and gradually increasing the dose is an effective way to reduce adverse reactions. Gastrointestinal reaction is the most common adverse reaction of metformin, mostly transient. In addition, the use of metformin alone will not lead to hypoglycemia, liver and kidney damage, and long-term use of metformin will not increase the risk of high lactic acid or lactic acidosis, but long-term use of metformin should pay attention to the possibility of vitamin B 12 deficiency. Metformin has a stable structure, does not bind to plasma protein, and is excreted with urine in its original form, which has the advantages of rapid clearance, short half-life, 90% clearance within 12 hours, and good safety.
Finally, acarbose and metformin are very safe oral hypoglycemic agents, and serious adverse reactions are rare. However, it should be noted that metformin will produce lactic acid during metabolism in the body. The use of metformin in patients with impaired liver and kidney function can obviously limit the scavenging ability of lactic acid and increase the risk of lactic acidosis. In addition, the use of metformin in patients with severe infection, hypoxia or major surgery will also increase the risk of lactic acidosis. Acarbose only works locally in the intestine, but it has almost no systemic effect. Therefore, acarbose is safer than metformin.