Insulin therapy is a treatment method that involves injecting or infusing insulin directly into the body using injection devices, primarily to regulate blood glucose levels. This therapy is targeted at patients with insufficient insulin secretion or abnormal insulin action, effectively preventing both acute and chronic complications caused by hyperglycemia. Depending on the severity and type of the condition, physicians will 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 its 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 destruction of pancreatic β-cells leading to absolute insulin deficiency. In Type 2 diabetes, insulin is used when oral medications fail to achieve targets 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 causing blood glucose fluctuations, insulin can serve as bridging therapy. Additionally, patients undergoing certain chemotherapy or steroid treatments who develop drug-induced hyperglycemia also prefer insulin as the first-line treatment.
The main route of administration is subcutaneous injection, typically in the abdomen, thigh, or buttocks, with rotation among 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 the elderly or those with renal impairment require dose adjustments to avoid hypoglycemia. Daily doses may be divided into basal insulin and bolus doses, such as long-acting insulin combined with rapid-acting pre-meal injections.
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 role in treating Type 1 diabetes.
Modern insulin preparations have greatly improved in purity and action profile, significantly reducing allergic reactions. Basal-plus therapy offers 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 mitigate this. Some patients may develop antibody responses reducing drug efficacy. Caution is needed when combined with alcohol or certain medications that may trigger hypoglycemia.
Contraindications include unawareness of hypoglycemia (asymptomatic hypoglycemia), allergy to insulin components, and infections at insulin pump sites. Daily blood glucose monitoring 4-7 times and regular renal and liver function tests are recommended. Reducing doses before vigorous exercise can prevent exercise-induced hypoglycemia.
Injection techniques should be carefully followed: needles should be withdrawn immediately after injection, and injections should avoid areas of bruising or infection. For diabetic ketoacidosis, IV fluids and electrolyte management are necessary; insulin alone is insufficient.
Combination with oral hypoglycemic agents (e.g., sulfonylureas) may increase hypoglycemia risk, requiring dose adjustments. β-blockers can mask hypoglycemia symptoms; selective β-blockers are preferred. NSAIDs may increase insulin resistance, necessitating closer blood glucose monitoring.
Concurrent use 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 can cause transient hyperglycemia.
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., Gla-100) have a 23% lower risk of hypoglycemia compared to traditional formulations. Long-term follow-up indicates that consistent users have a 12-15% reduced risk of cardiovascular disease.
Oral hypoglycemic drugs such as 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 via urinary glucose excretion but are not standalone treatments for Type 1 diabetes. Artificial pancreas systems (insulin pump + CGM) can automatically adjust doses but still rely on insulin as medication. All alternatives should be evaluated and prescribed by a physician.
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 hypoglycemic 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 improved, repeat the steps. 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 are recommended before exercise, and quick sugars should be carried for supplementation. If exercise intensity changes, adjust insulin doses 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 them?
Fasting blood glucose should be maintained between 70-130 mg/dL, and postprandial <180 mg/dL. Ongoing treatment is necessary even after achieving targets, as diabetes is a chronic condition. Treatment plans may be adjusted based on age, complications, or lifestyle, and medication should not be discontinued 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?
Insulin requirements often increase by 30-50% during pregnancy, especially in the second trimester, requiring weekly dose adjustments. Pre-pregnancy blood glucose should be well-controlled (HbA1c <6.5%), with blood glucose monitored 4-6 times daily during pregnancy. 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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