What is the recommended dosing and administration of NPH (Neutral Protamine Hagedorn) insulin for diabetes management?

NPH Insulin Dosing and Administration for Diabetes Management

The recommended initial dosing of NPH insulin is 10 units per day or 0.1-0.2 units/kg per day, with subsequent titration by 2 units every 3 days to reach fasting plasma glucose goals without hypoglycemia. 1

Initial Dosing and Administration

• Starting dose: 10 units per day or 0.1-0.2 units/kg per day 1, 2
• Administration timing options:
  • Once daily at bedtime
  • Twice daily (morning and bedtime)
  • Morning only for steroid-induced hyperglycemia 1

Titration Protocol

• Titration frequency: Adjust every 3 days 1
• Titration amount: Increase by 2 units if fasting plasma glucose remains above target 1
• Hypoglycemia management: If hypoglycemia occurs without clear reason, reduce dose by 10-20% 1
• Target: Set individualized fasting plasma glucose goals based on patient's overall clinical status 1

NPH Regimen Options

Once-Daily Bedtime NPH

• Best for patients with primarily elevated fasting glucose
• Consider switching to morning basal analog if patient experiences nocturnal hypoglycemia or frequently forgets evening doses 1

Twice-Daily NPH

• Conversion from once-daily: Total dose = 80% of current bedtime NPH dose
  • 2/3 given before breakfast
  • 1/3 given before dinner/bedtime 1
• Allows better coverage of both fasting and daytime glucose levels

Adding Prandial Insulin to NPH

When NPH alone is insufficient:

1. Initial prandial dose: 4 units per day or 10% of basal insulin dose 1
2. Titration: Increase by 1-2 units or 10-15% based on postprandial readings 1, 2
3. Options for administration:
   • Individual doses with meals
   • Self-mixed with NPH to reduce injection frequency 1

Premixed Insulin Options

• Consider premixed insulin (e.g., 70/30,75/25) to decrease injection frequency 1
• When converting from basal-bolus to premixed:
  • Use 70% of total daily dose as premixed insulin
  • 2/3 given before breakfast, 1/3 before dinner 2

Special Considerations

Steroid-Induced Hyperglycemia

• Timing: Administer NPH in the morning with steroid dose to synchronize peak insulin action with peak steroid effect 2
• Dosing: Initial dose 0.1-0.2 units/kg/day, with adjustments of 40-60% for higher glucocorticoid doses 2
• Monitoring: Check glucose every 2-4 hours during initial therapy, especially 4-6 hours after steroid administration 2
• Tapering: When reducing steroids, reduce insulin proportionally (approximately 0.4-0.5 units of NPH per mg of prednisone) 2

Comparative Efficacy

• Clinical studies show NPH insulin provides similar glycemic control to insulin glargine, with HbA1c reductions of approximately 0.6% in type 1 diabetes and 0.59% in type 2 diabetes 3
• However, NPH is associated with higher rates of nocturnal hypoglycemia compared to long-acting analogs (35.5% vs 26.5%) 4

Common Pitfalls and Caveats

1. Overbasalization: Watch for clinical signals such as:

   • Basal dose exceeding 0.5 units/kg/day
   • Elevated bedtime-to-morning glucose differential
   • Hypoglycemia (aware or unaware)
   • High glucose variability 1

2. Mixing restrictions:

   • NPH can be mixed with rapid-acting insulin
   • Do not mix phosphate-buffered insulins with lente insulins 2
   • Do not use rapid-acting or short-acting insulin at bedtime 2

3. Timing considerations:

   • NPH has a peak effect 4-10 hours after injection
   • Bedtime administration may cause nocturnal hypoglycemia
   • Consider morning administration for patients with recurrent nocturnal hypoglycemia 1

By following these structured recommendations for NPH insulin dosing and administration, clinicians can effectively manage diabetes while minimizing the risks of hypoglycemia and optimizing glycemic control.