What is the typical starting dose for insulin therapy?

Typical Starting Dose for Insulin Therapy

For patients with type 2 diabetes initiating insulin therapy, start with 10 units of basal insulin once daily OR 0.1-0.2 units/kg body weight once daily, administered at the same time each day. 1, 2, 3, 4

Initial Dosing Strategy

Standard Basal Insulin Initiation

• Fixed dose approach: 10 units once daily is the most straightforward starting point for most patients 1, 2, 3
• Weight-based approach: 0.1-0.2 units/kg/day provides a more tailored initial dose, particularly useful for patients at extremes of body weight 1, 2, 3, 4
• Basal insulin should be combined with metformin and possibly one additional non-insulin agent 1, 3

Type 1 Diabetes Requires Different Dosing

• Total daily insulin requirement: 0.4-1.0 units/kg/day, with 0.5 units/kg/day typical for metabolically stable patients 1, 2
• Approximately one-third of total daily insulin as basal insulin, with the remaining two-thirds as prandial (mealtime) insulin 1, 4
• Type 1 diabetes patients must receive both basal and prandial insulin from the start 1, 4

When to Consider Higher Starting Doses

For patients with severe hyperglycemia, consider starting with a basal-bolus regimen rather than basal insulin alone: 2, 3

• HbA1c ≥9% 2, 3
• Blood glucose ≥300-350 mg/dL 2, 3
• HbA1c 10-12% with symptomatic or catabolic features 2, 3

In these situations, start with 0.3-0.5 units/kg/day total daily dose, with half as basal insulin and half as prandial insulin 2

Dose Titration Protocol

Increase the basal insulin dose by 2-4 units (or 10-15% of current dose) once or twice weekly until fasting blood glucose reaches 80-130 mg/dL: 1, 2, 3

Specific Titration Algorithm

• If fasting glucose ≥180 mg/dL: increase by 4 units every 3 days 2
• If fasting glucose 140-179 mg/dL: increase by 2 units every 3 days 2
• If fasting glucose <80 mg/dL or hypoglycemia occurs: reduce dose by 10-20% 2

Patients can be taught to self-titrate using this algorithm, which improves glycemic control 1, 3

Critical Pitfall: Overbasalization

When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, ADD prandial insulin rather than continuing to escalate basal insulin alone. 2

Warning Signs of Overbasalization

• Basal insulin dose >0.5 units/kg/day 2
• High bedtime-to-morning glucose differential (≥50 mg/dL) 2
• Hypoglycemia episodes 2
• High glucose variability 2
• Fasting glucose at target but HbA1c remains elevated 2

Adding Prandial Insulin

If after 3-6 months of optimized basal insulin, fasting glucose is controlled but HbA1c remains above goal, add prandial insulin: 1, 2, 3

• Start with 4 units of rapid-acting insulin before the largest meal 1, 3
• Alternative: 10% of basal insulin dose per meal 1
• Alternative: 0.1 units/kg per meal 1
• Add to additional meals based on glucose patterns 2

Special Populations

Lower-Risk Dosing

For elderly patients (>65 years), those with renal failure, or poor oral intake, use the lower end of the dosing range (0.1-0.25 units/kg/day) to minimize hypoglycemia risk 2

Hospitalized Patients

• Insulin-naive or low-dose insulin: 0.3-0.5 units/kg total daily dose, with half as basal 2
• High-dose home insulin (≥0.6 units/kg/day): reduce total daily dose by 20% to prevent hypoglycemia 2

Administration Essentials

• Administer at the same time every day for consistent glucose control 2, 4
• Inject subcutaneously into abdomen, thigh, or deltoid 4
• Rotate injection sites within the same region to prevent lipodystrophy 4
• Never mix or dilute basal insulin (glargine) with other insulins due to its low pH 2, 4
• Daily fasting blood glucose monitoring is essential during titration 2

Medication Management

• Continue metformin when starting insulin 3
• Discontinue sulfonylureas to reduce hypoglycemia risk when using complex insulin regimens 3
• Consider continuing SGLT2 inhibitors or thiazolidinediones to reduce total insulin requirements 3