Insulin therapy is a method of treatment that involves injecting or infusing insulin directly into the body using injection devices, primarily to regulate blood glucose levels. This therapy is aimed at patients with insufficient insulin secretion or abnormal insulin action, effectively preventing acute and chronic complications caused by hyperglycemia. Depending on the severity and type of the condition, physicians select appropriate formulations and administration methods, combined with dietary and exercise plans.
The core goal is to mimic normal insulin secretion patterns, maintaining blood glucose within target ranges (usually fasting 70-130 mg/dL, postprandial <180 mg/dL). Precise regulation of insulin levels can reduce the risk of long-term complications such as diabetic foot ulcers, nephropathy, and retinopathy.
Insulin is classified into four categories based on action duration:
After subcutaneous injection, insulin binds to receptors on cell surfaces, promoting glucose transport into cells for metabolism and inhibiting hepatic glucose release. Combining different types of insulin can simulate physiological secretion patterns of "basal insulin + prandial insulin," such as basal-plus therapy combining long-acting insulin with rapid-acting insulin doses.
Primarily used for patients with Type 1 diabetes, due to complete deficiency of pancreatic beta-cell insulin secretion caused by destruction of these cells. In Type 2 diabetes, insulin is used when oral medications fail to achieve control or in cases of severe hyperglycemia (e.g., ketoacidosis). Pregnant women with gestational diabetes often use insulin to prevent fetal overgrowth and obstetric complications.
In special situations such as surgery, infections, or acute stress leading to blood glucose fluctuations, insulin can serve as bridging therapy. Additionally, patients undergoing certain chemotherapy or corticosteroid treatments who develop drug-induced hyperglycemia also primarily use insulin.
The main route of administration is subcutaneous injection, typically in the abdomen, thigh, or buttocks, rotating injection sites. Modern insulin pumps provide continuous basal insulin infusion and prandial doses before meals, mimicking physiological secretion. Initial doses are usually calculated based on body weight (e.g., 0.5-1.0 U/kg) and adjusted according to blood glucose monitoring results.
Blood glucose monitoring (target HbA1c generally <7%) and continuous glucose monitoring systems (CGM) are essential. Special populations such as elderly patients or those with renal impairment require dose adjustments to avoid hypoglycemia. Daily doses may be divided into basal insulin and prandial doses, such as long-acting insulin combined with rapid-acting insulin before meals.
Insulin acts directly on target tissues, allowing rapid and precise blood glucose reduction, especially in severe hyperglycemic emergencies where it is the only effective treatment. It fully restores cellular glucose utilization, preventing acute complications like ketoacidosis. Compared to oral medications, insulin has a unique therapeutic necessity for Type 1 diabetes.
Modern insulin preparations have significantly improved in purity and action profiles, greatly reducing allergic reactions. Basal-plus therapy offers more flexibility in daily activities and dietary changes, enhancing quality of life. Clinical evidence shows that regular use can delay the progression of diabetic retinopathy and nephropathy.
Hypoglycemia is the most common and serious side effect, especially with excessive doses or missed meals. Symptoms include trembling, cold sweat, palpitations, and in severe cases, confusion or coma. Long-term use may lead to weight gain due to excess insulin promoting fat and protein synthesis.
Local side effects include lipodystrophy or induration at injection sites; rotating injection sites can alleviate this. Some patients may develop antibody reactions, reducing drug efficacy. Caution is needed when combined with alcohol or certain medications that may trigger hypoglycemia.
Contraindications include unconscious hypoglycemia, insulin allergy, and infections at the infusion site in insulin pump users. Daily blood glucose monitoring 4-7 times and regular renal and liver function tests are necessary. Reducing doses before vigorous exercise can prevent exercise-induced hypoglycemia.
Injection techniques should be followed carefully: needles should be withdrawn immediately after injection, and injections should avoid areas of bruising or infection. In diabetic ketoacidosis, insulin should be combined with intravenous fluids and electrolyte management; it should not be used alone.
Using insulin with oral hypoglycemic agents (e.g., sulfonylureas) may increase hypoglycemia risk, requiring dose adjustments. Beta-blockers can mask hypoglycemia symptoms; selective beta-blockers are preferred. NSAIDs may increase insulin resistance, necessitating closer blood glucose monitoring.
Combination with anticoagulants like warfarin may increase bleeding risk, as hypoglycemia can affect coagulation. Before radiocontrast imaging, short-acting insulin should be temporarily discontinued, as contrast agents may temporarily elevate blood glucose levels.
Clinical trials confirm that regular insulin use can control HbA1c within target ranges, reducing microvascular complication risks by 39-50%. The DCCT study showed that intensified insulin therapy can delay the progression of retinopathy in Type 1 diabetes patients.
In Type 2 diabetes, basal insulin therapy can reduce HbA1c by an average of 1.5-2.0%, and newer human-like insulins (e.g., Glargine) have a 23% lower risk of hypoglycemia compared to traditional formulations. Long-term follow-up indicates that regular users have a 12-15% reduced risk of cardiovascular disease.
Oral hypoglycemic drugs like metformin can be used as initial treatment for Type 2 diabetes but cannot fully replace insulin in Type 1 diabetes. GLP-1 receptor agonists (e.g., exenatide) can delay gastric emptying and increase insulin secretion but are limited in severe hyperglycemia. SGLT2 inhibitors (e.g., dapagliflozin) lower blood glucose by promoting urinary glucose excretion but cannot be used alone for Type 1 diabetes. Artificial pancreas systems (insulin pump + CGM) can automatically adjust doses but still require insulin as medication. All alternative options should be evaluated and prescribed by a healthcare professional.
How to choose injection sites to avoid lipodystrophy?
It is recommended to rotate injection sites among the abdomen, outer thighs, and buttocks, with at least 2 cm between injection points. Avoid repeated injections in the same area, as the risk of lipodystrophy is directly related to injection technique and rotation frequency. After disinfecting with 75% isopropanol, wait for it to dry before injection to prevent skin irritation.
What should be done in case of hypoglycemia symptoms?
Immediately consume 15 grams of fast-acting carbohydrates, such as 150 cc of fruit juice or glucose tablets. Check blood glucose after 15 minutes; if not elevated, repeat the process. Continue monitoring for over 4 hours. Carry a glucose emergency kit at all times, and after symptoms subside, eat a small meal to prevent rebound hypoglycemia.
How should diet and exercise be coordinated during insulin therapy?
Rapid-acting insulin should be injected 15 minutes before meals, synchronized with eating times. Light doses may be added before exercise, and quick-acting carbohydrate supplements should be carried. If exercise intensity changes, adjust insulin doses accordingly and monitor blood glucose to prevent exercise-induced hypoglycemia.
What are the long-term blood glucose control targets, and is ongoing treatment necessary after reaching goals?
The general fasting blood glucose target is 70-130 mg/dL, and postprandial <180 mg/dL. Continued treatment is necessary even after achieving targets, as diabetes is a chronic condition. Treatment plans may be adjusted based on age, complications, or lifestyle, but medication should not be stopped without medical advice. HbA1c should be checked at least once a year to evaluate long-term control.
Do insulin treatment plans need adjustment during pregnancy?
During pregnancy, insulin requirements may increase by 30-50%, especially in the second trimester, requiring dose adjustments every 1-2 weeks. Preconception blood glucose should be well controlled (HbA1c <6.5%), with daily blood glucose monitoring 4-6 times. Rapid-acting insulins like Aspart are preferred. Postpartum, insulin doses usually decrease and should be reassessed within 24 hours after delivery.
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