What is the appropriate premix insulin dose for a patient with diabetes?

Premix Insulin Dosing

For insulin-naïve patients with diabetes, start premixed 70/30 insulin at 10 units or 0.1-0.2 units/kg/day divided into two equal doses given 30 minutes before breakfast and dinner. 1

Initial Dosing Strategy

For Insulin-Naïve Patients

• Begin with 10 units twice daily (before breakfast and dinner) or calculate 0.1-0.2 units/kg/day and split equally between these two meals 1
• Administer 30 minutes before meals to allow proper insulin action timing 2
• Use lower starting doses (closer to 0.1 units/kg/day) for high-risk patients: those aged >65 years, with renal failure, or poor oral intake 2, 3, 1

When Converting from Other Insulin Regimens

• Calculate total daily dose of current insulin and split 50% before breakfast and 50% before dinner 3
• Reduce total daily dose by 20% if the patient is currently taking >0.6 units/kg/day to prevent hypoglycemia 2, 3
• For example: A patient on Humalog 8 units TID plus Lantus 28 units at bedtime (total 52 units/day) should start with approximately 21 units before breakfast and 21 units before dinner (representing 80% of original dose) 2

Critical Safety Warning

Premixed 70/30 insulin carries a 4-6 times higher risk of hypoglycemia compared to basal-bolus regimens, requiring careful dose selection and patient counseling 2, 3

Dose Titration Protocol

• Adjust every 2 weeks based on fasting blood glucose, targeting 90-150 mg/dL 2, 3, 1
• Increase by 2 units if ≥50% of fasting values exceed goal 2, 3, 1
• Decrease by 2 units if >2 fasting values per week are <80 mg/dL 2, 3, 1

Expected Maintenance Doses

• Patients with type 2 diabetes commonly require ≥1 unit/kg/day or higher once titrated to goal 1
• This is substantially higher than type 1 diabetes requirements 1

When to Stop Escalating Premixed Insulin

Do not continue escalating 70/30 doses indefinitely if A1C remains above target. 2, 3, 1 Instead:

• When basal insulin exceeds 0.5 units/kg/day, consider adding a GLP-1 receptor agonist or converting back to basal-bolus regimen 2, 1
• Consider adding SGLT-2 inhibitor or transitioning to basal insulin plus GLP-1 RA for better control with less hypoglycemia 1

Patient Selection Criteria

Avoid premixed 70/30 insulin in patients with:

• Unpredictable eating patterns 2, 3, 1
• Need for flexible dosing 2, 3
• Inability to eat similar carbohydrate amounts at consistent meal times 2, 3

Concomitant Medications

• Continue metformin unless contraindicated when initiating or intensifying 70/30 insulin 2, 1
• Discontinue sulfonylureas and DPP-4 inhibitors to reduce hypoglycemia risk and avoid unnecessarily complex regimens 1

Common Pitfalls to Avoid

• Never use premixed 70/30 insulin in hospital settings due to unacceptably high hypoglycemia rates 3
• Patients must carry quick-acting carbohydrates at all times due to elevated hypoglycemia risk 3
• The fixed 70:30 ratio limits separate adjustment of basal versus prandial components, making this regimen inappropriate for patients requiring precise dosing control 3, 1