What dose adjustment is recommended when converting from Levemir (insulin detemir) to NovoRapid (insulin aspart)?

Converting from Levemir to NovoRapid: Insulin Dosing Adjustments

When converting from Levemir (insulin detemir) to NovoRapid (insulin aspart), a complete change in insulin regimen is required as these are fundamentally different types of insulin with distinct pharmacokinetic profiles.

Understanding the Insulin Types

• Levemir (insulin detemir): A long-acting basal insulin analog with duration of action 12-24 hours 1
• NovoRapid (insulin aspart): A rapid-acting insulin analog with onset of action 0.25-0.5 hours, peak at 1-3 hours, and duration of 3-5 hours 1

Conversion Principles

1. Direct unit-for-unit conversion is not appropriate as these insulins serve different purposes:

   • Levemir provides background insulin coverage throughout the day
   • NovoRapid provides mealtime coverage with rapid onset and short duration

2. Recommended approach:

   • Calculate total daily insulin requirement
   • Distribute insulin between basal and bolus components
   • Use NovoRapid for bolus (mealtime) needs only

Specific Conversion Algorithm

1. Determine total daily insulin requirement:

   • Start with the current total daily Levemir dose
   • For patients with type 2 diabetes: 0.3-0.5 units/kg/day 1
   • For patients with type 1 diabetes: 0.5-0.8 units/kg/day 1

2. Distribution of insulin:

   • NovoRapid should be used as prandial (mealtime) insulin only
   • Typically 50% of total daily insulin should be prandial 1
   • Divide NovoRapid doses across meals based on carbohydrate content

3. Starting NovoRapid dose:

   • Initial dose: 4 units per meal or 10% of basal insulin dose 1
   • Titrate by 1-2 units or 10-15% based on postprandial glucose readings 1

4. Basal insulin coverage:

   • NovoRapid cannot replace basal insulin
   • Must add a basal insulin (like glargine or NPH) to the regimen
   • For basal coverage: 50% of total daily insulin requirement 1

Special Considerations

• Hypoglycemia risk: Monitor closely during transition as NovoRapid has faster onset and shorter duration than Levemir 1
• Renal impairment: Reduce NovoRapid dose by 25% for patients with CKD stage 3 and by 50% for CKD stage 5 1
• Timing of administration: NovoRapid should be administered 0-15 minutes before meals 1
• Monitoring: Check blood glucose before meals and 2 hours after meals during transition period

Practical Example

For a 70kg patient on 35 units of Levemir daily:

1. Calculate 50% of total daily dose for prandial insulin: 17.5 units
2. Distribute NovoRapid across three meals: ~6 units per meal (adjust based on meal size)
3. Implement a basal insulin (not NovoRapid) for the remaining 17.5 units

Common Pitfalls to Avoid

• Never use NovoRapid as a basal insulin - its short duration of action (3-5 hours) makes it unsuitable for basal coverage 1
• Don't convert directly unit-for-unit between these insulins as they have completely different pharmacokinetic profiles
• Avoid delaying NovoRapid administration - it should be given immediately before meals for optimal effect
• Don't forget to maintain basal insulin coverage when adding NovoRapid to the regimen

Remember that NovoRapid is specifically designed for mealtime insulin coverage and cannot replace the long-acting properties of Levemir. A complete insulin regimen redesign is necessary when making this transition.