What should the Lantus (insulin glargine) dose, NPH (neutral protamine Hagedorn) insulin dose, and carbohydrate ratio be for a patient taking prednisone (40 mg) with hyperglycemia, currently receiving Lantus (15 units) and NPH (25 units) with a carb ratio of 1:12?

Insulin Dose Adjustments for Steroid-Induced Hyperglycemia

Immediate Insulin Regimen Changes

Your current insulin regimen is grossly inadequate for the degree of hyperglycemia you're experiencing on prednisone 40 mg daily, and requires immediate aggressive intensification with NPH insulin specifically targeting steroid-induced daytime hyperglycemia.

NPH Insulin Dosing

• Increase NPH from 25 units to 35-40 units given in the morning to match the peak hyperglycemic effect of prednisone, which occurs between midday and midnight 1, 2, 3
• Morning administration of NPH is specifically recommended for steroid-induced hyperglycemia because its 4-6 hour peak action aligns with glucocorticoid-induced hyperglycemia patterns 2, 3
• For patients on high-dose glucocorticoids (40 mg prednisone), initial NPH dosing should be 0.3-0.4 units/kg, which would be approximately 35-40 units for most adults 2
• The current 25 units of NPH is insufficient given your blood glucose readings consistently in the 200-300s mg/dL range 2

Lantus (Basal Insulin) Adjustment

• Increase Lantus from 15 units to 20-25 units given once daily at bedtime to address the elevated overnight and fasting glucose 4
• Your overnight blood glucose of 226 mg/dL indicates inadequate basal insulin coverage 4
• Increase basal insulin by 4 units every 3 days when fasting glucose is ≥180 mg/dL until reaching target of 80-130 mg/dL 4
• Continue titrating Lantus separately from NPH, as they serve different purposes—Lantus provides 24-hour basal coverage while NPH specifically targets steroid-induced daytime hyperglycemia 2, 3

Carbohydrate Ratio Adjustment

• Change your carbohydrate ratio from 1:12 to 1:8 or even 1:6 for meals during peak steroid effect (lunch and dinner) 2
• Patients on high-dose steroids require 40-60% more prandial insulin than standard dosing due to increased insulin resistance 1, 2
• Your current ratio of 1:12 is far too conservative given blood glucose readings of 323 mg/dL before dinner and 337 mg/dL before bed 2
• Consider using a more aggressive ratio of 1:6 for the largest meals (lunch and dinner) when steroid effect is maximal 2

Titration Protocol

Daily Monitoring Requirements

• Check blood glucose before each meal and at bedtime (minimum 4 times daily) 4, 2
• For the first 24-48 hours after adjustments, check every 2-4 hours to identify patterns 3
• Target fasting glucose 80-130 mg/dL and daytime glucose 140-180 mg/dL 4, 2

NPH Titration Schedule

• Increase NPH by 2 units every 3 days if pre-dinner glucose remains >180 mg/dL 2, 3
• If hypoglycemia occurs (glucose <70 mg/dL), reduce NPH dose by 10-20% immediately 2, 3
• Watch for the characteristic "midday to midnight" hyperglycemia pattern—if this persists despite adjustments, consider splitting NPH to twice daily (2/3 morning, 1/3 evening) 3

Lantus Titration Schedule

• Increase Lantus by 4 units every 3 days if fasting glucose remains ≥180 mg/dL 4
• Increase by 2 units every 3 days if fasting glucose is 140-179 mg/dL 4
• Continue until fasting glucose consistently reaches 80-130 mg/dL 4

Correction Insulin Scale

• For blood glucose 150-200 mg/dL: add 2 units rapid-acting insulin 2
• For blood glucose 201-250 mg/dL: add 4 units 2
• For blood glucose 251-300 mg/dL: add 6 units 2
• For blood glucose 301-350 mg/dL: add 8 units 2
• For blood glucose >350 mg/dL: add 10 units and notify provider 2

Critical Considerations for Steroid Taper

• As prednisone dose decreases, reduce NPH by 10-20% for each significant steroid dose reduction to prevent hypoglycemia 2, 3
• The NPH dose must be adjusted proportionally with steroid tapering—failure to do so will result in severe hypoglycemia 2, 3
• Lantus dose may also need reduction but typically less aggressively than NPH 3
• Monitor glucose every 2-4 hours during the first 24-48 hours after any steroid dose change 3

Common Pitfalls to Avoid

• Never continue current inadequate insulin doses when blood glucose readings are consistently 200-300+ mg/dL—this prolongs dangerous hyperglycemia exposure 4
• Never fail to match NPH timing with morning steroid administration—giving NPH at the wrong time will lead to inadequate daytime coverage and nocturnal hypoglycemia 2, 3
• Never use the same carbohydrate ratio throughout the day on high-dose steroids—daytime meals require more aggressive ratios than breakfast 2
• Never forget to reduce insulin doses as steroids taper—this is the most common cause of severe hypoglycemia in patients on tapering steroids 2, 3
• Do not rely solely on correction insulin to manage steroid-induced hyperglycemia—scheduled insulin doses must be adequate 4

Why This Regimen Works

• Prednisone causes hyperglycemia predominantly between midday and midnight, with peak effect 4-8 hours after morning administration 1, 5
• NPH insulin peaks at 4-6 hours, perfectly matching the steroid's hyperglycemic effect when given in the morning 2, 3, 5
• Studies show that NPH-based regimens provide better daytime glucose control than glargine-based regimens in patients on steroids, though both are effective 5
• Your current regimen under-treats daytime hyperglycemia (evidenced by 323 mg/dL pre-dinner and 337 mg/dL pre-bed readings) while potentially causing nocturnal hypoglycemia with inadequate basal coverage 5