What is the recommended increase in NPH (Neutral Protamine Hagedorn) insulin dose for a patient with hyperglycemia, currently taking 70 units of NPH insulin and requiring an additional 23 units of Novolog (insulin aspart), with blood glucose readings of 303 and 310?

NPH Insulin Dose Adjustment for Persistent Hyperglycemia

Increase the NPH insulin by 10-20% (7-14 units), bringing the total dose to 77-84 units daily, administered as a split dose with approximately 2/3 in the morning (51-56 units) and 1/3 in the evening (26-28 units).

Rationale for Dose Increase

• Blood glucose readings of 303 and 310 mg/dL despite requiring 23 units of supplemental Novolog indicate inadequate basal insulin coverage, necessitating NPH dose escalation 1
• The current NPH dose of 70 units is insufficient to suppress hepatic glucose production and control fasting/between-meal hyperglycemia, as evidenced by the need for substantial correctional insulin 1
• A 10-20% increase (7-14 units) represents an appropriate initial adjustment that balances efficacy with hypoglycemia risk 1, 2

Recommended Dosing Strategy

• Split the increased NPH dose into twice-daily administration: approximately 51-56 units in the morning and 26-28 units at bedtime (following the 2/3 morning, 1/3 evening distribution) 3
• This split-dose approach provides superior 24-hour glucose coverage compared to once-daily dosing, particularly for patients with persistent hyperglycemia like this case 3
• The morning dose should be larger to cover daytime metabolic demands and nutritional needs 2

Alternative Conservative Approach

• If concerned about hypoglycemia risk, use the more conservative titration strategy: increase NPH by 2 units every 3 days until target blood glucose is achieved 1, 2
• This gradual approach is safer but will take longer to achieve glycemic control 1

Monitoring and Further Adjustments

• Monitor blood glucose every 2-4 hours for the first 24-48 hours after dose adjustment to identify patterns of hyper- or hypoglycemia 1, 2
• Target inpatient glucose goals of fasting <130 mg/dL and daytime 140-180 mg/dL 1
• If hypoglycemia occurs (<70 mg/dL), immediately reduce the corresponding NPH dose by 10-20% without waiting 1, 2
• If hyperglycemia persists after 3 days at the new dose, increase by an additional 2 units every 3 days 1, 2

Addressing the Prandial Insulin Component

• The 23 units of Novolog required suggests significant postprandial hyperglycemia that NPH alone cannot address 4
• Consider formalizing a prandial insulin regimen with rapid-acting insulin before meals (starting with 4 units per meal or 10% of basal dose) rather than relying solely on correctional doses 3
• This basal-bolus approach is superior to sliding scale insulin alone for achieving glycemic targets 4, 5

Critical Safety Considerations

• Watch for the pattern of "overbasalization"—if increasing NPH further still requires substantial correctional insulin, this signals the need for more structured prandial coverage rather than additional basal insulin 3
• 84% of patients experiencing severe hypoglycemia had a preceding mild hypoglycemia episode, making early detection crucial 2
• Avoid giving all NPH at bedtime only, as this will not adequately cover daytime hyperglycemia 3

Common Pitfalls to Avoid

• Do not continue indefinitely with high-dose correctional insulin without adjusting the basal dose—this reactive approach leads to poor glycemic control and increased hypoglycemia risk 5
• Avoid making multiple simultaneous adjustments; change one component at a time to identify the source of glycemic variability 1
• If renal or hepatic impairment is present, start with the lower end of the dose increase range (10% rather than 20%) 3