Adjusting Insulin Doses for Optimal Glucose Control

Introduction to Insulin Adjustment

• The American Diabetes Association recommends adjusting insulin doses systematically based on self-monitored blood glucose values, with basal insulin titrated by 2 units every 3 days until fasting glucose reaches 80-130 mg/dL, and prandial insulin added when basal insulin exceeds 0.5 units/kg/day or when postprandial hyperglycemia persists despite controlled fasting glucose 1, 2

Basal Insulin Titration

• For patients on basal insulin, the American Diabetes Association suggests starting with 10 units once daily or 0.1-0.2 units/kg/day for insulin-naive patients with type 2 diabetes 1, 2
• For severe hyperglycemia, consider 0.3-0.4 units/kg/day as the starting dose 2
• For type 1 diabetes, total daily insulin is typically 0.4-1.0 units/kg/day, with approximately 50% as basal insulin 3, 2

Titration Schedule

• If fasting glucose ≥180 mg/dL, increase basal insulin by 4 units every 3 days 4
• If fasting glucose 140-179 mg/dL, increase basal insulin by 2 units every 3 days 4
• If fasting glucose 80-130 mg/dL, maintain current basal insulin dose 1, 2
• If >2 fasting values per week <80 mg/dL, decrease basal insulin by 2 units 1, 4

Prandial Insulin Initiation and Adjustment

• When adding prandial insulin, start with 4 units of rapid-acting insulin before the largest meal or the meal causing greatest postprandial excursion 2, 4
• Alternative: use 10% of current basal dose as the initial prandial dose 2
• Titrate prandial insulin by 1-2 units or 10-15% every 3 days based on pre-meal and 2-hour postprandial glucose readings 2

Monitoring Requirements

• Daily self-monitoring of blood glucose is essential during titration, with checks of fasting glucose, premeal glucose, and 2-hour postprandial glucose 6, 7, 4, 1
• Reassess every 3 days during active titration and every 3-6 months once stable 2

Special Populations and Situations

• For hospitalized patients, consider 0.3-0.5 units/kg/day total insulin, with half as basal, and reduce total daily dose by 20% for high-dose home insulin 2
• For patients on enteral/parenteral feeding, basal insulin needs are 30-50% of total daily requirement, and start with 10 units glargine every 24 hours or 5 units NPH/detemir every 12 hours 2

Foundation Therapy Considerations

• Metformin should be continued when adding or intensifying insulin therapy unless contraindicated, with a starting dose of 500 mg daily and increase every 2 weeks as tolerated for older adults with eGFR ≥45 mL/min 5, 2
• Consider adding GLP-1 receptor agonist to basal insulin regimen to improve A1C while minimizing weight gain and hypoglycemia risk 2, 4

Administration Technique

• Rotate injection sites within the same region rather than between regions, and use the abdomen for fastest absorption rate 7
• Do not use rapid- or short-acting insulin at bedtime, and do not mix or dilute insulin glargine with other insulins due to low pH 1, 2