What to do for a patient with uncontrolled T2DM on Mixtard 35 (insulin) and metformin (Metformin) with morning hyperglycemia while on hydrocortisone (corticosteroid) therapy?

Management of Morning Hyperglycemia in T2DM Patient on Mixtard and Metformin During Hydrocortisone Therapy

You need to immediately increase the evening Mixtard insulin dose to approximately 50-55 units (150% of current dose) and intensify blood glucose monitoring to every 4-6 hours, as the hydrocortisone is causing severe steroid-induced hyperglycemia that requires aggressive insulin adjustment. 1, 2

Understanding the Problem

Your patient's morning glucose of 360 mg/dL represents severe hyperglycemia directly caused by the hydrocortisone therapy. Glucocorticoids cause hyperglycemia through three mechanisms: 1

• Impaired beta-cell insulin secretion
• Increased insulin resistance
• Enhanced hepatic gluconeogenesis

The critical issue is that glucocorticoids cause disproportionate daytime hyperglycemia that persists overnight, which explains why the morning glucose remains severely elevated despite evening insulin administration. 1, 2

Immediate Insulin Adjustment Required

Evening Mixtard Dose Increase

Increase the evening Mixtard dose from 35 units to 50-55 units (approximately 150% of baseline) starting tonight. 2, 3 This aggressive increase is necessary because:

• Steroid-induced hyperglycemia requires substantially higher insulin doses than typical adjustments 1
• The current 35 units is clearly insufficient given the morning glucose of 360 mg/dL 2
• Patients on glucocorticoids often require "extraordinary amounts" of insulin 1

Duration of Increased Dosing

Maintain this increased dose for at least 24-48 hours after each hydrocortisone administration, then gradually taper back toward baseline as blood glucose normalizes. 2, 4 The hyperglycemic effects of corticosteroids persist well beyond the immediate administration period. 1

Metformin Optimization

Continue metformin 1 gram, but consider the following adjustments: 1

• If the patient is taking immediate-release metformin twice daily, ensure both doses are being taken consistently 5
• Metformin alone is insufficient for steroid-induced hyperglycemia but provides important background insulin sensitization 1, 6
• Do not discontinue metformin unless contraindicated (eGFR <30 mL/min/1.73 m²) 1

Critical Monitoring Protocol

Implement intensive glucose monitoring immediately: 1, 2

• Check blood glucose every 4-6 hours while on hydrocortisone therapy
• Pay particular attention to afternoon and evening readings, as steroid-induced hyperglycemia peaks 7-9 hours after administration 2, 4
• Monitor overnight/fasting values to assess adequacy of evening insulin dose 4

Adding Correctional Insulin

You need to add rapid-acting insulin for correctional coverage: 1

• Use regular human insulin subcutaneously every 6 hours OR rapid-acting analog (lispro, aspart, glulisine) every 4 hours 1
• Start with a correction scale: for glucose >200 mg/dL, give 2-4 units; >250 mg/dL, give 4-6 units; >300 mg/dL, give 6-8 units 1
• Adjust the correction factor based on response over 24 hours 2

Algorithmic Approach to Dose Titration

Follow this decision tree for the next 48-72 hours: 2, 4

If morning glucose remains >250 mg/dL after first dose increase:

• Increase evening Mixtard by an additional 10-15 units (to 60-70 units total) 2
• Add or increase correctional insulin doses 1
• Consider splitting insulin to twice-daily NPH if hyperglycemia persists 1, 4

If morning glucose drops to 100-180 mg/dL:

• Maintain current increased dose for 24 more hours 2
• Begin gradual taper (reduce by 10-20% every 1-2 days) once consistently <180 mg/dL 4

If morning glucose <100 mg/dL:

• Immediately reduce evening Mixtard by 20-30% to prevent hypoglycemia 4
• This scenario is unlikely initially but becomes critical risk 48-72 hours after stopping hydrocortisone 4

Critical Pitfall to Avoid

The most dangerous error is maintaining the increased insulin doses beyond 24-48 hours after hydrocortisone is discontinued. 4 When steroid effects dissipate, insulin requirements drop rapidly, creating severe hypoglycemia risk. You must:

• Proactively reduce insulin doses as soon as hydrocortisone is stopped 4
• Decrease Mixtard to approximately 50-65% of the peak steroid dose within 48 hours of stopping hydrocortisone 4
• Continue intensive monitoring for 72 hours after steroid discontinuation 4

Special Considerations for Mixtard

Mixtard is a premixed insulin (30% regular, 70% NPH), which has limitations for steroid-induced hyperglycemia: 1

• The fixed ratio may not provide optimal coverage for the variable hyperglycemia pattern caused by steroids 1
• If target glucose is not achieved with dose increases up to 60-70 units, consider switching to a basal-bolus regimen (long-acting basal insulin plus mealtime rapid-acting insulin) for better flexibility 1, 4

When to Consider Additional Interventions

If glucose remains >300 mg/dL despite 150% insulin dose increase: 1

• This represents severe uncontrolled diabetes requiring more aggressive intervention 1
• Consider temporary addition of basal insulin (glargine or detemir) in addition to Mixtard 1
• Evaluate for insulin resistance factors (infection, other medications) 1

Patient Education Points

Counsel the patient that: 4, 3

• Higher insulin doses are temporary and necessary due to hydrocortisone 2
• They should carry at least 15 grams of fast-acting carbohydrate for hypoglycemia once steroids are stopped 3
• Symptoms of hyperglycemia (increased thirst, urination, fatigue) should prompt immediate glucose check 1