How do you convert Novorapid (insulin aspart) pump units to long-acting and short-acting insulin syringes?

Converting NovoRapid Pump Units to Long-Acting and Short-Acting Insulin Syringes

When converting from NovoRapid (insulin aspart) pump therapy to multiple daily injections (MDI), the total daily insulin dose should remain approximately the same, with 50% allocated to basal insulin and the remaining 50% distributed as bolus insulin across meals. 1

Conversion Formula

Step 1: Calculate Total Daily Dose (TDD)

• Add up all insulin delivered via the pump in a 24-hour period:
  • Total basal insulin over 24 hours
  • All bolus/mealtime insulin over 24 hours
  • Any correction doses given

Step 2: Distribute the Insulin

• Basal (Long-Acting) Insulin: 50% of TDD
• Bolus (Short-Acting) Insulin: 50% of TDD, divided among meals

Detailed Algorithm

1. For basal insulin:

   • Start with 50% of the TDD as long-acting insulin (insulin glargine, detemir, or degludec)
   • Administer once daily (some patients may require twice-daily dosing with detemir or glargine) 1

2. For bolus insulin:

   • Use NovoRapid (insulin aspart) for meal coverage
   • Distribute the remaining 50% of TDD across meals based on carbohydrate intake
   • Typical distribution if carb intake is similar at each meal:
     • Breakfast: 15-20% of TDD
     • Lunch: 15-20% of TDD
     • Dinner: 15-20% of TDD

3. Titration after conversion:

   • Adjust basal insulin based on fasting and between-meal glucose levels
   • Adjust bolus insulin based on post-meal glucose readings
   • Follow the "increase 2 units every 3 days" rule to reach target without hypoglycemia 1

Important Considerations

• Insulin sensitivity varies throughout the day, so the distribution of bolus insulin may need adjustment based on individual response 1
• Avoid overbasalization - if basal dose exceeds 0.5 units/kg/day, reassess the regimen 2
• Monitor closely for the first 48-72 hours after conversion, as adjustments are commonly needed
• Insulin aspart (NovoRapid) can be mixed with NPH insulin without significant loss of rapid-acting effect 3, but should not be mixed with lente insulins 1

Common Pitfalls to Avoid

1. Forgetting to reduce the total dose: Some patients may require a 10-20% reduction in total insulin when switching from pump to injections due to differences in insulin delivery and absorption 4

2. Using incorrect mixing techniques: If mixing insulins in one syringe:

   • Draw up clear insulin (NovoRapid) first
   • Then draw up cloudy insulin (NPH)
   • Inject within 15 minutes before a meal 1

3. Inadequate monitoring: More frequent blood glucose monitoring is essential during the transition period to ensure appropriate dosing

4. Ignoring correction factors: Maintain the same insulin sensitivity factor (correction factor) used in the pump for high glucose corrections

By following this structured approach to converting from insulin pump therapy to multiple daily injections, you can maintain glycemic control while transitioning between insulin delivery methods.