What is the standard dose decrease for Humulin N (NPH insulin) in a patient with type 2 diabetes experiencing hypoglycemia?

Standard Dose Decreases for Humulin N (NPH Insulin)

For hypoglycemia without a clear reversible cause, reduce Humulin N by 10-20% immediately. 1, 2

Immediate Dose Reduction Protocol

Determining the Reduction Amount:

• Use a 20% reduction for severe hypoglycemia, recurrent episodes (≥2 events per week), or nocturnal hypoglycemia 1, 2
• Use a 10% reduction for mild, isolated hypoglycemic events 2
• First, always investigate for a clear reversible cause (missed meal, unusual exercise, medication error) before adjusting the dose 1, 2

Post-Reduction Monitoring Requirements

Intensified glucose monitoring is mandatory after any dose reduction:

• Check fasting blood glucose daily for at least one week 2
• For nocturnal hypoglycemia specifically: check at bedtime, 3:00 AM, and upon waking for several days 2, 3
• Target fasting glucose range: 80-130 mg/dL 1, 2

Subsequent Titration After Dose Reduction

After one week of the reduced dose:

• If >50% of fasting glucose values remain above target: increase by 2 units 2
• If ≥2 fasting glucose values per week fall below 80 mg/dL: decrease by an additional 2 units 2
• Make adjustments every 3 days during active titration 1, 2

Special Considerations for NPH Insulin

NPH-specific adjustments when hypoglycemia occurs:

• If on bedtime NPH with nocturnal hypoglycemia: consider converting to twice-daily NPH plan with total dose = 80% of current bedtime dose 1
• Consider switching NPH administration from evening to morning to reduce nocturnal hypoglycemia risk 2
• If converting from bedtime NPH to twice-daily: give 2/3 before breakfast and 1/3 before dinner 1

Critical Threshold Warning: Overbasalization

Watch for signs that NPH dose is excessive:

• Basal dose >0.5 units/kg/day 1, 4
• High bedtime-to-morning glucose differential (≥50 mg/dL) 1, 2
• Recurrent hypoglycemia (aware or unaware) 1
• High glucose variability 1

When these signs appear, adding prandial insulin coverage is more appropriate than continuing to escalate NPH alone 1

Alternative Insulin Options for Persistent Hypoglycemia

Consider switching to newer basal analogs if hypoglycemia persists despite dose reduction:

• Insulin degludec (Tresiba) or U-300 glargine (Toujeo) have lower nocturnal hypoglycemia rates than NPH insulin 2, 3, 5, 6
• Long-acting basal analogs (U-100 glargine or detemir) reduce symptomatic and nocturnal hypoglycemia risk by 26-59% compared with NPH insulin 1, 5, 6

Common Pitfalls to Avoid

• Never continue the same NPH dose without adjustment after a hypoglycemic event—this significantly increases risk of recurrent severe hypoglycemia 2
• Never delay dose reduction when hypoglycemia occurs—75% of hospitalized patients who experienced hypoglycemia had no insulin dose adjustment before the next administration 4
• Ensure glucagon is available for all patients on NPH insulin 2, 3

Hypoglycemia Unawareness Assessment

If recurrent hypoglycemia continues despite dose reductions:

• Evaluate for hypoglycemia unawareness, which requires more frequent monitoring and potentially less aggressive glycemic targets 2, 3
• Scrupulous avoidance of hypoglycemia for 2-3 weeks can reverse hypoglycemia unawareness 4, 3

Follow-Up Timing

Schedule reassessment within 1-2 weeks after any dose reduction to review glucose logs, identify patterns, and make further adjustments as needed 2, 3