What should the NPH insulin dose and insulin‑to‑carbohydrate ratio be tomorrow after stopping dexamethasone, given the current regimen of 22 units NPH with a 1 unit per 6 g carbohydrate ratio while on dexamethasone?

NPH Insulin and Carbohydrate Ratio Adjustment After Dexamethasone Discontinuation

Reduce the NPH dose to approximately 15–18 units tomorrow morning (a 20–30% reduction from 22 units) and liberalize the carbohydrate ratio to 1 unit per 8 grams of carbohydrate. 1

Rationale for Dose Reduction

• Insulin requirements drop precipitously within 24–48 hours after stopping dexamethasone, often by 50–70%, because the steroid-induced insulin resistance resolves rapidly. 1
• The American Diabetes Association specifically recommends reducing NPH insulin by 10–20% when tapering steroids to prevent hypoglycemia, but complete discontinuation warrants a more aggressive 20–30% initial reduction with close monitoring. 1
• Dexamethasone causes severe insulin resistance requiring 40–60% higher insulin doses than baseline; removing this effect means your current 22-unit dose is now excessive for tomorrow's metabolic state. 2, 1

Carbohydrate Ratio Adjustment

• Tighten the carbohydrate ratio from 1:6 to approximately 1:8 (a 25–30% reduction in prandial insulin requirements), reflecting the resolution of steroid-induced mealtime insulin resistance. 1
• This adjustment prevents post-meal hypoglycemia while maintaining adequate coverage as glucocorticoid effects dissipate. 1

Monitoring Protocol for the First 48 Hours

• Check blood glucose every 2–4 hours during the first day off dexamethasone to identify patterns of hypoglycemia or residual hyperglycemia. 1, 3
• Target a fasting glucose < 130 mg/dL and daytime glucose 140–180 mg/dL. 1, 3
• If any glucose reading falls < 70 mg/dL, immediately reduce the NPH dose by an additional 10–20% (2–4 units) without waiting for further data. 1

Algorithmic Titration After Day 1

• If fasting glucose remains > 130 mg/dL for three consecutive mornings after stopping dexamethasone, increase NPH by 2 units every 3 days until target is achieved. 1, 4
• If afternoon/evening glucose consistently exceeds 180 mg/dL, tighten the carbohydrate ratio incrementally (e.g., from 1:8 to 1:7) rather than increasing NPH, because NPH's peak action (4–6 hours post-injection) may not adequately cover late-day meals. 1, 3
• If hypoglycemia recurs, further reduce NPH by 10–20% and liberalize the carbohydrate ratio to 1:10. 1

Common Pitfalls to Avoid

• Do not maintain the full 22-unit NPH dose tomorrow; failure to reduce insulin promptly after steroid cessation is the most common cause of severe hypoglycemia in this scenario. 1
• Avoid using the same carbohydrate ratio (1:6) that was appropriate during dexamethasone therapy, as this will result in excessive prandial insulin and post-meal hypoglycemia. 1
• Do not delay dose adjustments if hypoglycemia occurs; the risk of recurrent hypoglycemia is highest in the 24–72 hours immediately following steroid discontinuation. 1

Special Considerations

• The risk of hypoglycemia peaks between midnight and 6 AM during the transition off steroids, so close monitoring of fasting glucose is essential. 1
• If the patient has a history of hypoglycemia unawareness or is elderly, consider a more aggressive initial reduction (30–40%) to 13–15 units NPH and a carbohydrate ratio of 1:10. 1, 3