How do you adjust insulin doses for patients on steroid (corticosteroid) therapy?

Adjusting Insulin for Steroid Use

For patients on once-daily intermediate-acting steroids like prednisone, add NPH insulin administered in the morning concomitantly with the steroid dose, starting at 0.1-0.2 units/kg/day, in addition to any existing basal insulin or oral agents. 1

Understanding Steroid-Induced Hyperglycemia Patterns

The type and timing of steroid administration dictates your insulin strategy:

• Intermediate-acting steroids (prednisone, prednisolone) cause disproportionate daytime hyperglycemia with peak effects 4-6 hours after morning administration, while glucose often normalizes overnight regardless of treatment 1
• Long-acting steroids (dexamethasone) or multidose/continuous steroid regimens cause sustained hyperglycemia requiring different insulin coverage 1
• Glucocorticoids induce hyperglycemia in 56-86% of hospitalized patients with or without preexisting diabetes, and untreated hyperglycemia increases mortality, infection risk, and cardiovascular events 1

Insulin Selection Based on Steroid Type

For Once or Twice-Daily Intermediate-Acting Steroids (Prednisone, Prednisolone)

NPH insulin is the preferred formulation because its peak action at 4-6 hours matches the pharmacokinetic profile of these steroids 1, 2:

• Administer NPH in the morning concomitantly with the steroid dose 1
• Add NPH to existing basal-bolus insulin or oral glucose-lowering medications 1
• Initial dose: 0.1-0.2 units/kg/day 2

For Long-Acting Steroids (Dexamethasone) or Continuous Use

Increase long-acting basal insulin to manage fasting hyperglycemia 1:

• Long-acting basal insulin (glargine, degludec) is required for sustained 24-hour coverage 1
• Consider combination of basal insulin plus NPH for comprehensive coverage 3

Dosing Strategy for High-Dose Steroids

For higher steroid doses, substantially increase prandial and correctional insulin by 40-60% or more in addition to basal insulin 1:

• Start with total daily insulin dose of 0.5 units/kg if insulin-naive 4
• If already on insulin, increase pre-steroid dose by at least 30% 4
• Distribute insulin as approximately 25-40% basal and 60-75% prandial for optimal daytime coverage 5, 6
• Patients achieving normoglycemia require higher percentages of nutritional insulin (58% of total daily dose) versus correctional insulin (7% of total daily dose) 5

Titration Protocol

Increase insulin by 2 units every 3 days until target glucose is achieved without hypoglycemia 1, 2:

• Target blood glucose: 100-180 mg/dL 1
• Monitor glucose every 2-4 hours initially, then before meals and at bedtime 1, 3
• Pay particular attention to afternoon and evening values when steroid effect peaks 7

Managing Hypoglycemia

If hypoglycemia occurs, reduce the corresponding insulin dose by 10-20% after determining and addressing the cause 1, 2:

• Nocturnal hypoglycemia with morning steroids suggests excessive basal insulin—this is a common pitfall with long-acting insulin regimens 7, 4
• NPH insulin avoids this problem by having minimal overnight activity when steroid effects wane 2, 7

Adjusting During Steroid Taper

Reduce insulin doses proportionally as steroids are tapered to prevent hypoglycemia 2:

• Decrease NPH by 10-20% with each steroid dose reduction 2
• Monitor closely as insulin requirements decrease rapidly after steroid discontinuation 3
• For patients on twice-daily NPH, focus reductions on the morning dose when tapering morning steroids 2

Special Populations

Patients with Type 1 Diabetes

• Always maintain basal insulin even if steroids are discontinued to prevent diabetic ketoacidosis 1, 2

Patients Receiving Enteral/Parenteral Nutrition

• Administer NPH two or three times daily (every 8-12 hours) to cover continuous feeding 1
• Calculate nutritional insulin as 1 unit per 10-15 grams of carbohydrate in the formula 1

Perioperative Patients

• Hold NPH on the day of surgery and give 75-80% of long-acting basal insulin dose 1
• Monitor glucose every 2-4 hours while NPO 1

Critical Pitfalls to Avoid

• Do not rely on sliding scale insulin alone—this approach is associated with poor glycemic control and has been discouraged in guidelines 3
• Do not use long-acting basal insulin as monotherapy for morning intermediate-acting steroids—this causes nocturnal hypoglycemia and inadequate daytime coverage 7, 4
• Do not delay insulin adjustments—daily titration based on glucose patterns and anticipated steroid changes is critical 1
• Do not forget to adjust antidiabetic medications—corticosteroids increase blood glucose concentrations requiring dosage adjustments of all antidiabetic agents 8