What adjustments should be made to the insulin regimen, including Lantus (insulin glargine) dose, carb ratio, and correction scale, for a patient who was previously taking dexamethasone 4mg and has a current blood glucose level ranging from 110-140 mg/dL, with a carb ratio of 1:3 and a correction factor of 15 units, now that the steroid has been discontinued?

Insulin Adjustment After Discontinuing Dexamethasone

Immediate Lantus Reduction

Reduce your Lantus dose from 90 units to approximately 45-60 units (50-65% of the increased dose) today, as you are now beyond the peak steroid effect and maintaining the current dose creates substantial hypoglycemia risk. 1

• Dexamethasone causes hyperglycemia that peaks 7-9 hours after administration and persists for at least 24 hours, but effects substantially diminish by 48 hours 1
• Insulin requirements decline rapidly after dexamethasone is stopped, and doses must be adjusted accordingly to prevent hypoglycemia 1
• The transition from 24 to 48 hours post-dexamethasone is a high-risk period for hypoglycemia if insulin doses are not appropriately reduced 1

Specific Dosing Algorithm:

• If your blood glucose is 100-140 mg/dL today: Reduce Lantus to 45-50 units (approximately 50-55% of current dose) 1
• If your blood glucose remains >180 mg/dL today: Reduce Lantus to 55-60 units (approximately 60-65% of current dose) and reassess in 12 hours 1

Carbohydrate Ratio Adjustment

Return your carb ratio from 1:3 to approximately 1:8 or 1:10 (representing a 60-70% reduction in mealtime insulin from the peak steroid period) to prevent hypoglycemia as insulin resistance normalizes. 1

• The carbohydrate ratio should be adjusted to account for the decreased insulin resistance now that dexamethasone has been discontinued 1
• Monitor pre-meal and 2-hour post-meal glucose levels to fine-tune this ratio over the next 24 hours 1

Correction Scale Modification

Use a standard correction scale rather than the aggressive scale needed during steroid therapy, as insulin sensitivity is returning to baseline. 1

• Your insulin sensitivity factor (ISF) should return from 15 to approximately 30-40 (meaning 1 unit of insulin will lower blood glucose by 30-40 mg/dL instead of 15 mg/dL) 1
• Administer correction insulin every 4-6 hours as needed, but expect significantly less need for corrections compared to the steroid period 1

Critical Monitoring Requirements

Check blood glucose every 4-6 hours for the next 24-48 hours, with particular attention to overnight and fasting values when hypoglycemia risk is highest. 1

• The most dangerous error is maintaining the increased insulin doses beyond 24-48 hours after steroid discontinuation, as this creates severe hypoglycemia risk when steroid effects dissipate 1
• If blood glucose consistently falls below 70 mg/dL, further reduce Lantus by an additional 10-20% 1

Common Pitfalls to Avoid

• Do not maintain the 90-unit Lantus dose - this was appropriate only during active dexamethasone effect and will cause severe hypoglycemia now 1
• Do not reduce insulin doses too slowly - the rapid decline in steroid effect requires prompt dose reduction to prevent dangerous hypoglycemia 1
• Avoid using sulfonylureas during this transition period as they increase hypoglycemia risk 1

Gradual Return to Baseline

• Continue to reduce Lantus dose back toward your pre-steroid baseline over the next 2-3 days, decreasing by 10-20% every 1-2 days while monitoring closely for hypoglycemia 1
• Dexamethasone is a long-acting glucocorticoid, so some residual effect may persist beyond 48 hours, requiring continued monitoring for 72 hours 1