Immediate Addition of NPH Insulin for Steroid-Induced Hyperglycemia
Yes, add NPH insulin immediately—morning prednisone 20 mg is driving afternoon/evening hyperglycemia that your current basal-only regimen cannot address.
Why NPH Is the Correct Choice
- Prednisone peaks 4–8 hours after morning dosing, producing pronounced afternoon and evening hyperglycemia while glucose typically normalizes overnight 1, 2.
- NPH insulin peaks 4–6 hours after injection, perfectly aligning with prednisone's hyperglycemic surge when given in the morning 1, 2.
- Your current Lantus 6 units provides flat 24-hour basal coverage but cannot match the temporal glucose spike caused by morning prednisone 1, 2.
Specific NPH Dosing Protocol
Initial Dose
- Start NPH 8–10 units subcutaneously every morning (approximately 0.1–0.13 units/kg for your 77 kg weight) 1, 2.
- Administer NPH at the same time as your morning prednisone dose to synchronize insulin peak with steroid effect 1, 2.
Rationale for This Dose
- High-dose glucocorticoids typically require 40–60% additional insulin beyond baseline needs 1, 2.
- Your current total daily insulin is only ~18 units (6 U Lantus + ~12 U prandial at 1:12 ratio for typical meals), which is profoundly insufficient for prednisone 20 mg 1, 2.
Adjusting Your Existing Regimen
Keep Lantus at 6 Units
- Do not increase Lantus—your fasting glucose is not the problem 1, 2.
- Lantus provides overnight basal coverage; NPH will handle the daytime steroid effect 1, 2.
Tighten Carbohydrate Ratio
- Change from 1:12 to 1:8 (1 unit per 8 g carbohydrate) for lunch and dinner 1, 2.
- This reflects the 40–60% increase in prandial insulin needed during steroid therapy 1, 2.
Add Correction Insulin Protocol
- Use rapid-acting insulin (lispro or aspart) every 4 hours during the day when glucose >150 mg/dL 1, 2:
Monitoring and Titration
First 48 Hours
- Check glucose every 2–4 hours (before meals, 2 hours after meals, bedtime, and 3 AM) 1, 2.
- Target daytime glucose 140–180 mg/dL and fasting <130 mg/dL 1, 2.
NPH Titration After 3 Days
- If afternoon/evening glucose remains >180 mg/dL, increase NPH by 2 units every 3 days until target achieved 1, 2.
- If any glucose <70 mg/dL occurs, reduce NPH by 10–20% immediately (1–2 units) 1, 2.
When Prednisone Is Tapered
- Reduce NPH by 20–30% for every 5 mg prednisone reduction 1, 2.
- Anticipate a 50–70% drop in total insulin needs after complete prednisone cessation 1, 2.
Why Not Just Increase Lantus?
- Lantus provides peak-less 24-hour coverage—increasing it will cause nocturnal hypoglycemia without adequately covering the daytime steroid surge 3, 4.
- Your elevated 1700 and 2100 glucose readings indicate inadequate daytime insulin, not inadequate basal insulin 1, 2.
- NPH's intermediate-acting profile is specifically designed for this temporal mismatch 1, 2.
Critical Safety Points
- Never give NPH at bedtime for prednisone-induced hyperglycemia—this will cause severe nocturnal hypoglycemia when the steroid effect wanes 1, 2.
- Do not rely solely on correction insulin—scheduled NPH is required to prevent the hyperglycemic surge 1, 2.
- Avoid premixed insulin (70/30) in this setting—it lacks the flexibility for rapid dose adjustments and carries high hypoglycemia risk 5, 1.
Expected Outcomes
- With NPH 8–10 units morning + tightened carb ratio, expect afternoon/evening glucose to fall to 140–180 mg/dL within 3–5 days 1, 2.
- Your fasting glucose should remain stable at current levels since Lantus dose is unchanged 1, 2.
- Total daily insulin will increase to approximately 30–35 units (6 U Lantus + 10 U NPH + ~15 U prandial), which is appropriate for your weight and steroid dose 1, 2.