What is the correction scale for a patient on Lantus (insulin glargine) 20 units twice daily (bid)?

Correction Scale for Lantus 20 Units BID

For a patient on Lantus 20 units twice daily (40 units total daily), use a simplified correction scale of 2 units of rapid-acting insulin for premeal glucose >250 mg/dL and 4 units for premeal glucose >350 mg/dL, while recognizing this patient likely needs a comprehensive basal-bolus regimen rather than relying primarily on correction doses. 1

Immediate Correction Scale Recommendation

The American Diabetes Association provides explicit guidance for simplified sliding scales in older adults that can be applied here 1:

• Premeal glucose >250 mg/dL (13.9 mmol/L): Give 2 units of short- or rapid-acting insulin 1
• Premeal glucose >350 mg/dL (19.4 mmol/L): Give 4 units of short- or rapid-acting insulin 1
• Stop sliding scale when not needed daily 1

Critical Context: This Regimen Requires Reassessment

The fact that this patient is on Lantus 20 units twice daily (40 units total) suggests they likely need scheduled prandial insulin, not just correction doses. 2

Why This Matters:

• Scheduled insulin regimens with basal, prandial, and correction components are preferred over relying solely on correction insulin 2
• When basal insulin exceeds 0.5 units/kg/day and glucose remains elevated, adding scheduled prandial insulin is more appropriate than continuing to escalate basal insulin alone 2
• Blood glucose requiring frequent correction doses likely reflects both inadequate basal coverage AND postprandial excursions requiring mealtime insulin 2

Proper Basal-Bolus Approach

If this patient requires regular correction doses, they should transition to a scheduled basal-bolus regimen 2:

• Start prandial insulin: 4 units of rapid-acting insulin before the largest meal, or 10% of the current basal dose (approximately 4 units) 2
• Titrate prandial insulin: Increase by 1-2 units or 10-15% every 3 days based on pre-meal and 2-hour postprandial glucose readings 2
• Continue metformin unless contraindicated, as it remains the foundation of type 2 diabetes therapy 2

Calculating Insulin Sensitivity Factor (Alternative Method)

For a more individualized correction scale, calculate the insulin sensitivity factor 2:

• Formula: 1500 ÷ Total Daily Dose (TDD) 2
• For this patient: 1500 ÷ 40 units = 37.5 mg/dL per unit 2
• This means 1 unit of rapid-acting insulin should lower blood glucose by approximately 37-38 mg/dL 2

Common Pitfalls to Avoid

• Do not continue increasing Lantus beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia, as this leads to suboptimal control and increased hypoglycemia risk 2
• Do not rely solely on correction insulin when scheduled prandial coverage is needed 2
• Recognize that Lantus given twice daily at 20 units per dose may indicate the patient has already exceeded typical once-daily dosing capacity and needs comprehensive insulin intensification 3

Patient Education Requirements

• Proper insulin injection technique and site rotation 2
• Recognition and treatment of hypoglycemia (treat at ≤70 mg/dL with 15 grams of fast-acting carbohydrate) 2
• Self-monitoring of blood glucose 2
• "Sick day" management rules 2
• Insulin storage and handling 2