What is the recommended dosing and management for Insulin Mixtard (70/30) (Novomix, biphasic insulin aspart) therapy?

Insulin Mixtard 70/30 Is Not Recommended for Hospital Use

Premixed insulin therapy (human insulin 70/30, which includes Mixtard) is associated with an unacceptably high rate of iatrogenic hypoglycemia and is not recommended in the hospital setting. 1

Outpatient Management of Mixtard 70/30

For outpatient diabetes management where Mixtard 70/30 is being considered or already in use, the following approach should guide therapy:

Initial Dosing Strategy

• Start with 0.3-0.5 units/kg/day divided into two doses (before breakfast and dinner) for insulin-naïve patients with type 1 or type 2 diabetes 2
• Administer 5-15 minutes before breakfast and dinner to optimize postprandial glucose control 2
• Distribute approximately 2/3 of the total daily dose before breakfast and 1/3 before dinner rather than equal dosing 2

High-Risk Populations Requiring Dose Reduction

• Use lower starting doses (closer to 0.3 units/kg/day) for elderly patients (>65 years), those with renal impairment, or patients at higher risk of hypoglycemia 1, 2
• Reduce the total daily insulin dose by 10-20% if hypoglycemia occurs 2

Monitoring Requirements

• Implement more frequent blood glucose monitoring during initiation, focusing on both fasting and postprandial glucose levels 2
• Adjust the evening dose based on pre-dinner and bedtime glucose readings 2
• Monitor during transition periods between insulin regimens, as this is when hypoglycemia risk is highest 2

Critical Limitations and Pitfalls

Why Mixtard 70/30 Is Problematic

The fixed ratio of 70% intermediate-acting and 30% short-acting insulin creates several clinical challenges:

• Lacks flexibility compared to basal-bolus regimens, requiring rigid meal timing to avoid hypoglycemia 2, 3
• Higher glycemic variability compared to multiple daily basal-bolus injections 3, 4
• Cannot be mixed with other insulins in the same syringe 2
• Requires consistent meal timing and carbohydrate intake to match the fixed insulin action profile 2

When to Avoid Mixtard 70/30

• Never use in hospitalized patients due to unacceptably high hypoglycemia rates 1
• Avoid in patients with unpredictable meal patterns or variable carbohydrate intake 2
• Not appropriate for patients requiring flexible insulin dosing 3

Superior Alternative: Basal-Bolus Regimen

A basal-bolus approach provides better glycemic control, reduced complications, and greater flexibility compared to premixed insulin formulations 1, 4:

• Start with 0.3-0.5 units/kg/day total, with 50% as basal insulin (once or twice daily) and 50% as rapid-acting insulin (divided before three meals) 1
• Basal-bolus regimens reduce postoperative complications including wound infection, pneumonia, bacteremia, and acute renal/respiratory failure 1
• Patient satisfaction and quality of life are significantly better with basal-bolus compared to premixed insulin 4
• Glycemic variability is lower with basal-bolus regimens 4

Basal-Plus as Middle Ground

For patients with mild hyperglycemia or decreased oral intake:

• Use a single dose of basal insulin (0.1-0.25 units/kg/day) plus corrective doses of rapid-acting insulin before meals or every 6 hours if fasting 1
• This approach reduces hypoglycemia risk while maintaining adequate glycemic control 1

Special Consideration: Enteral Nutrition

Premixed insulin has been suggested for patients receiving enteral nutrition, though data remain limited 1. Even in this context, careful monitoring for hypoglycemia is essential.