What adjustments can be made to the treatment plan for a patient with hyperglycemia on 80 units of NPH insulin and preprandial insulin R?

Adjusting Insulin Therapy for Persistent Hyperglycemia on NPH and Preprandial Regular Insulin

For a patient with persistent hyperglycemia (blood glucose peaking at 400 mg/dL) despite 80 units of NPH insulin and preprandial regular insulin, the most effective approach is to convert to a twice-daily NPH regimen with adjusted prandial insulin dosing to better match the steroid-induced hyperglycemia pattern.

Understanding the Current Situation

The patient is currently on:

• 80 units of NPH insulin (once daily)
• Preprandial regular insulin (recently added)
• Prednisone (which is causing significant hyperglycemia)

Despite this regimen, blood glucose levels are still peaking at 400 mg/dL, indicating inadequate glycemic control.

Recommended Treatment Adjustments

1. Convert to Twice-Daily NPH Regimen

• Initial Conversion:
  • Calculate total daily NPH dose = 80% of current NPH dose (64 units total)
  • Distribute as: 2/3 in morning (43 units), 1/3 at bedtime (21 units) 1
  • This split better matches insulin action with steroid-induced hyperglycemia patterns

2. Adjust Prandial Insulin Coverage

• For Regular Insulin (R):
  • Start with 4 units per meal or 10% of the reduced NPH dose 1
  • Consider higher doses (40-60% increase) for meals following steroid administration 2
  • Titrate by increasing 1-2 units or 10-15% twice weekly based on postprandial readings 1

3. Timing of Administration

• Morning Dose:
  • Administer morning NPH with the prednisone dose to synchronize peak insulin action with peak steroid effect 2
  • Give prandial insulin 30 minutes before meals for optimal postprandial coverage

4. Blood Glucose Monitoring

• Monitor blood glucose 4-6 hours after steroid administration to capture peak hyperglycemic effect 2
• Check fasting and pre-meal glucose levels to guide insulin adjustments
• Target blood glucose range: 80-180 mg/dL during steroid therapy 2

Titration Algorithm

1. For NPH:

   • Increase morning NPH by 2 units every 3 days if afternoon/evening glucose remains >180 mg/dL
   • Increase evening NPH by 2 units every 3 days if fasting glucose remains >130 mg/dL
   • Reduce dose by 10-20% if hypoglycemia occurs 1

2. For Regular Insulin:

   • Adjust each meal dose independently based on 2-hour postprandial readings
   • Increase by 1-2 units if postprandial glucose >180 mg/dL
   • Decrease by 10-20% if hypoglycemia occurs 1

Special Considerations for Steroid-Induced Hyperglycemia

• Steroid Effect Pattern: Prednisone causes disproportionate hyperglycemia during the day with potential normalization overnight 2
• NPH Timing: Morning NPH better matches the pharmacokinetics of morning prednisone administration 2
• Prednisone Tapering: As prednisone is tapered, insulin doses should be reduced proportionally (approximately 0.4-0.5 units of NPH per mg of prednisone) 2

Common Pitfalls to Avoid

1. Misalignment of insulin and steroid peaks: Failing to time NPH administration with prednisone dosing can lead to persistent hyperglycemia 2
2. Inadequate prandial coverage: Steroid-induced hyperglycemia often requires higher mealtime insulin doses than typical 2
3. Overbasalization: Using excessive basal insulin without adequate prandial coverage can lead to overnight hypoglycemia while still having daytime hyperglycemia 1
4. Delayed adjustments: Waiting too long between dose adjustments can prolong poor glycemic control 1

By implementing this structured approach with twice-daily NPH and adjusted prandial insulin, the patient's blood glucose levels should improve significantly, reducing the risk of complications associated with persistent hyperglycemia while on steroid therapy.