NPH Insulin Regimen for Steroid-Induced Hyperglycemia
For a 63-year-old male weighing 105.9 kg with BMI 31 currently on Lantus 20 units and starting prednisone 60 mg, the recommended NPH insulin dose is 20-25 units in the morning, with a carbohydrate ratio of 1:10 and a correction scale of 1 unit for every 40-50 mg/dL above 150 mg/dL. 1, 2
NPH Insulin Dosing
- Initial NPH insulin dose should be 0.1-0.2 units/kg per day (10.6-21.2 units for this patient), administered in the morning to coincide with the peak hyperglycemic effect of prednisone 2, 3
- For high-dose glucocorticoids (60 mg prednisone qualifies), insulin requirements typically increase by 40-60% above standard dosing 2, 3
- NPH insulin is specifically recommended for steroid-induced hyperglycemia due to its intermediate-acting profile that peaks at 4-6 hours, which aligns with the peak hyperglycemic effect of morning prednisone 1, 2
- Consider continuing the patient's Lantus 20 units while adding NPH, as the American Diabetes Association recommends NPH in addition to daily basal insulin for steroid-induced hyperglycemia 1
Carbohydrate Ratio
- Start with a carbohydrate ratio of approximately 1:10 (1 unit of rapid-acting insulin per 10g of carbohydrate) 1, 2
- This ratio may need to be more aggressive (1:8 or 1:6) during peak steroid effect (afternoon and evening) 2, 3
- For patients with insulin resistance related to obesity (BMI 31), carbohydrate ratios may need to be more aggressive than standard recommendations 2
Correction Scale
- Initial correction scale: 1 unit of rapid-acting insulin for every 40-50 mg/dL above target (150 mg/dL) 1, 2
- More aggressive correction may be needed in the afternoon and evening when steroid effect peaks 1, 2
- For this patient with obesity and on high-dose steroids, consider a more aggressive correction scale: 2 units for every 50 mg/dL above 150 mg/dL 2, 4
Monitoring and Adjustment Protocol
- Monitor blood glucose every 2-4 hours initially, with special attention to afternoon and evening values when steroid effect peaks 1
- For persistent hyperglycemia, increase NPH dose by 2 units every 3 days until target blood glucose is achieved 2, 4
- If hypoglycemia occurs, reduce NPH dose by 10-20% 2
- Target blood glucose range should be 80-180 mg/dL 1
Special Considerations
- Morning administration of NPH insulin is specifically recommended to match the pharmacokinetic profile of daily prednisone therapy 1, 2
- Prednisone causes disproportionate hyperglycemia during the day, with blood glucose often normalizing overnight 1
- NPH insulin has been shown to require lower total daily insulin doses compared to glargine-based regimens for steroid-induced hyperglycemia 5, 4
- A more aggressive initial NPH dose (0.5 units/mg prednisone equivalent) has been associated with better glycemic control without increased hypoglycemia risk 4
Common Pitfalls to Avoid
- Avoid relying solely on long-acting insulin (Lantus) without adding NPH, as this may lead to inadequate coverage of daytime hyperglycemia 1, 6
- Beware of nocturnal hypoglycemia risk if NPH dose is too high, as prednisone effect wanes overnight 1, 6
- Consider splitting the NPH dose (2/3 morning, 1/3 evening) if daytime hyperglycemia persists despite dose adjustments 2
- Insulin requirements typically decrease rapidly after steroid discontinuation, requiring prompt dose adjustments to avoid hypoglycemia 2, 3