Is it appropriate to continue titrating NPH (Neutral Protamine Hagedorn) insulin up or down by 2 units based on the previous evening's fasting blood sugar levels?

NPH Insulin Titration Based on Fasting Blood Sugar

Yes, titrating NPH insulin by 2 units based on the previous evening's fasting blood sugar is appropriate and aligns with current diabetes management guidelines. 1

Evidence-Based Titration Approach

The American Diabetes Association's 2025 Standards of Care specifically recommends a titration algorithm for basal insulin (including NPH) that involves:

• Setting a fasting plasma glucose (FPG) target
• Increasing dose by 2 units every 3 days to reach FPG target without hypoglycemia
• For hypoglycemia: determining cause and lowering dose by 10-20% if no clear reason 1

Specific Titration Protocol

For NPH insulin specifically:

• Initial dose: 10 units/day or 0.1-0.2 units/kg/day
• Titration: Adjust by 2 units based on fasting glucose values
• If >50% of fasting glucose values are above target: Increase by 2 units
• If >2 fasting glucose values/week are <80 mg/dL: Decrease by 2 units 1

Important Considerations

Monitoring for Hypoglycemia

• NPH has a peak action at 4-6 hours after injection, creating a higher risk of nocturnal hypoglycemia compared to long-acting analogs 2
• If hypoglycemia occurs, determine the cause and reduce the dose by 10-20% 1

Timing Considerations

• For bedtime NPH dosing, monitor morning fasting glucose
• Consider switching from evening NPH to a basal analog if the patient develops hypoglycemia or frequently forgets evening doses 1

Overbasalization Risk

• Be cautious about continuously increasing basal insulin without improvement
• Signs of overbasalization include basal doses >0.5 units/kg/day, high glucose variability, or hypoglycemia 1
• Consider adding other agents or switching to twice-daily NPH if glycemic targets aren't met 1

Special Populations

For older adults:

• Consider simplified insulin regimens
• May use more conservative glucose targets (90-150 mg/dL)
• If >50% of premeal values are above goal, increase dose
• If >2 premeal values/week are <90 mg/dL, decrease dose 1

Alternative Approaches

If the current approach isn't achieving targets:

1. Consider converting to twice-daily NPH regimen (2/3 morning, 1/3 evening)
2. Consider adding prandial insulin with meals
3. Consider switching to a longer-acting basal insulin analog to reduce hypoglycemia risk 1

The 2-unit adjustment approach is evidence-based, simple for patients to follow, and has been shown to be effective in clinical studies evaluating self-titration algorithms 3, 4.