How can switching from Lantus (insulin glargine) to a twice-daily premixed insulin regimen, such as 70/30 NPH (neutral protamine Hagedorn)/regular insulin, 70/30 aspart mix, or 75/25 lispro mix, improve glycemic control for a patient currently on 60 units of Lantus once daily?

Switching from Lantus to Twice-Daily Premixed Insulin

Switching from once-daily Lantus (60 units) to twice-daily premixed insulin should be implemented by calculating 80% of the total daily Lantus dose (48 units), split into two injections before breakfast and dinner, to improve postprandial glycemic control.

Benefits of Switching to Premixed Insulin

Switching from basal insulin (Lantus) to twice-daily premixed insulin offers several advantages for improving glycemic control:

• Provides both basal and prandial coverage in a single injection, addressing both fasting and postprandial glucose excursions 1
• Improves postprandial glycemic control compared to basal-only regimens 1, 2
• Reduces the postprandial-to-preprandial glucose differential that may occur with basal-only therapy 1
• Can be particularly effective when A1C remains above target despite optimized basal insulin 1
• Simplifies regimen compared to basal-bolus therapy (fewer daily injections) 2

Implementation Process

Step 1: Calculate Initial Dose

• Calculate 80% of the current total daily Lantus dose 1, 2
• For 60 units of Lantus: 60 × 0.8 = 48 units total daily dose of premixed insulin

Step 2: Split the Dose

• Divide the total daily dose into two injections:
  • 2/3 (approximately 32 units) before breakfast
  • 1/3 (approximately 16 units) before dinner 1

Step 3: Timing of Administration

• For 70/30 NPH/regular: Administer 30 minutes before meals
• For 70/30 aspart mix or 75/25 lispro mix: Administer 0-15 minutes before meals 2

Step 4: Monitor and Adjust

• Check blood glucose before breakfast, lunch, dinner, and bedtime
• Target pre-meal glucose levels according to individualized goals
• Adjust morning dose based on pre-dinner glucose readings
• Adjust evening dose based on fasting morning glucose readings 1

Choice of Premixed Insulin

The three main options for premixed insulin include:

1. 70/30 NPH/regular insulin

   • More economical option
   • Slower onset, longer duration
   • Requires administration 30 minutes before meals

2. 70/30 aspart mix or 75/25 lispro mix

   • Faster onset, better postprandial control
   • Can be administered closer to mealtime (0-15 minutes)
   • May reduce risk of hypoglycemia compared to NPH/regular 2, 3

3. 70/30 degludec/aspart mix

   • Newer option with more flexible dosing
   • Can be administered once or twice daily 2

Practical Considerations

• Continue metformin if the patient is currently taking it 1, 4
• Consider discontinuing sulfonylureas, DPP-4 inhibitors, and GLP-1 receptor agonists when switching to premixed insulin 1, 2
• Premixed insulins work best with consistent meal timing and carbohydrate content 2
• Irregular meal patterns may increase risk of hypoglycemia with premixed insulin regimens 2
• More frequent blood glucose monitoring is recommended during the transition period 5

Potential Challenges and Solutions

• Hypoglycemia risk: Start with 80% of the Lantus dose to reduce this risk; adjust based on glucose patterns 1
• Meal timing variability: If the patient has irregular meal patterns, a basal-bolus regimen might be more appropriate 2
• Daytime hyperglycemia: May require adjustment of the morning dose or consideration of thrice-daily dosing 2

Expected Outcomes

Research has shown that switching to premixed insulin can improve glycemic control, particularly postprandial glucose levels 6, 7. In one study, patients switching to premixed insulin experienced significant reductions in HbA1c without increased hypoglycemia risk 6.