What is the initial insulin protocol for a type 2 diabetic patient?

Initial Insulin Protocol for Type 2 Diabetes

Start basal insulin at 10 units once daily or 0.1-0.2 units/kg body weight, continue metformin, and titrate every 3 days based on fasting glucose until reaching 80-130 mg/dL. 1, 2

Starting Basal Insulin

• Initiate with long-acting basal insulin (glargine, detemir, or degludec) rather than NPH insulin due to reduced nocturnal hypoglycemia risk 1
• Administer 10 units once daily for most patients with mild-to-moderate hyperglycemia, or use 0.1-0.2 units/kg/day when tailoring to body weight 1, 2
• For insulin detemir specifically, administer once daily with the evening meal or at bedtime; if twice-daily dosing becomes necessary, give the evening dose with dinner, at bedtime, or 12 hours after the morning dose 3
• Continue metformin unless contraindicated, as it reduces all-cause mortality and cardiovascular events, and when combined with insulin decreases weight gain, lowers insulin dose requirements, and reduces hypoglycemia 1, 2, 4
• Do not abruptly discontinue other oral medications when starting insulin due to rebound hyperglycemia risk 5

Titration Algorithm

Use a systematic approach based on fasting glucose measurements every 3 days: 1, 2

• If fasting glucose ≥180 mg/dL: increase basal insulin by 4 units every 3 days 1, 2
• If fasting glucose 140-179 mg/dL: increase basal insulin by 2 units every 3 days 1, 2
• Target fasting glucose: 80-130 mg/dL 1, 2

Patient self-titration using these algorithms improves glycemic control 2

Monitoring Requirements

• Daily fasting blood glucose monitoring is essential during the titration phase 1, 2
• Assess insulin dose adequacy at every clinical visit 1
• Increase monitoring frequency during any regimen changes 2
• Provide comprehensive education on self-monitoring, hypoglycemia recognition and treatment, proper injection technique, insulin storage, and sick day rules 6, 2

When Basal Insulin Alone Is Insufficient

If HbA1c targets are not met after optimizing basal insulin, you have two evidence-based options:

Option 1: Add GLP-1 Receptor Agonist 1

• Preferred for patients concerned about weight gain and hypoglycemia
• Improves HbA1c while minimizing these risks
• Fixed-ratio combination products available (lixisenatide/glargine or liraglutide/degludec) 6

Option 2: Add Prandial Insulin 1, 2

• Start with 4 units of rapid-acting insulin before the largest meal, or 10% of the current basal dose 1
• Use rapid-acting analogs (lispro, aspart, or glulisine) dosed just before meals for better postprandial control than regular insulin 6
• If still inadequate, advance to basal-bolus regimen with 2 or more prandial injections 6

Alternative: Premixed Insulin 6

• Can use twice-daily premixed insulin (70/30 NPH/regular, 70/30 aspart, or 75/25 or 50/50 lispro) before breakfast and dinner 6
• If inadequate, advance to thrice-daily premixed insulin analogues 6
• Less flexible than basal-bolus but simpler regimen 6

Common Pitfalls to Avoid

• Avoid intramuscular injections, especially with long-acting insulins, as severe hypoglycemia may result 5
• Rotate injection sites within the same region (thigh, abdomen, or upper arm) to prevent lipohypertrophy, which distorts insulin absorption 3, 5
• Do not inject into lipohypertrophic areas 5
• Some patients with type 2 diabetes may require more detemir than NPH insulin (mean doses 0.77 U/kg vs 0.52 U/kg in clinical studies) 3
• Use the shortest needles (4-mm pen or 6-mm syringe needles) as first-line choice—they are safe, effective, and less painful 5

Special Considerations

For markedly hyperglycemic or symptomatic patients at diagnosis, insulin may be initiated at higher doses or with more intensive regimens from the start 6. For hospitalized patients, start with 0.3-0.5 units/kg/day total daily dose, giving 50% as basal insulin 1, 2.