What should the initial NPH (Neutral Protamine Hagedorn) insulin dose be for an elderly male patient with no prior insulin therapy, receiving methylprednisolone (methylprednisolone) 125 mg at home?

NPH Insulin Dosing for Steroid-Induced Hyperglycemia

Start NPH insulin at 0.1-0.2 units/kg per day (approximately 7-14 units for a 70 kg patient), administered in the morning to match the hyperglycemic peak of methylprednisolone. 1

Initial Dosing Strategy

For an elderly male patient receiving methylprednisolone 125 mg with no prior insulin use:

• Calculate the starting dose as 0.1-0.2 units/kg per day, which translates to approximately 7-14 units for a typical 70 kg patient 1
• Administer the entire NPH dose in the morning to align with the pharmacokinetic profile of daily glucocorticoid therapy, as the steroid causes predominantly midday-to-midnight hyperglycemia 1, 2
• Consider the higher end of dosing (0.2 units/kg or ~14 units) for this patient given the high methylprednisolone dose of 125 mg, as patients on high-dose glucocorticoids typically require 40-60% more insulin than standard dosing 1, 2

Monitoring Protocol

• Check blood glucose every 2-4 hours for the first 24-48 hours after initiating NPH to identify patterns of hyperglycemia or hypoglycemia 1, 3
• Target fasting glucose <130 mg/dL and daytime glucose 140-180 mg/dL for hospitalized elderly patients 1
• Focus monitoring on pre-meal, 2-hour post-meal, and bedtime values to assess adequacy of NPH coverage 2

Dose Titration Guidelines

• If hyperglycemia persists (>50% of readings above target), increase NPH by 2 units every 3 days until target blood glucose is achieved 1, 2
• If hypoglycemia occurs (<70 mg/dL), immediately reduce the NPH dose by 10-20% without waiting for additional episodes 1, 3
• Watch for the characteristic "midday to midnight" hyperglycemia pattern of prednisone; if this persists despite dose adjustments, consider splitting NPH to twice daily (2/3 morning, 1/3 evening) 1, 2

Special Considerations for Elderly Patients

• Once-daily basal insulin injection therapy is associated with minimal side effects and may be a reasonable option in elderly patients 4
• Assess the patient's visual and motor skills and cognitive ability, as insulin therapy requires that patients or caregivers can administer insulin safely 4
• Consider the patient's living situation and support networks, as these affect diabetes management and should be included in shared decision-making 4

Critical Pitfalls to Avoid

• Do not administer NPH at bedtime for steroid-induced hyperglycemia, as this mismatches the timing of steroid-induced hyperglycemia and increases nocturnal hypoglycemia risk 1, 5
• Do not use a glargine-based regimen as first-line, as research shows isophane (NPH) is equally effective and better matched to the steroid's hyperglycemic pattern 5
• When methylprednisolone is tapered or discontinued, immediately reduce NPH by 10-20% to prevent hypoglycemia, as insulin requirements decline rapidly after glucocorticoids are stopped 1, 2

Supplemental Coverage

• Implement a conservative sliding scale with rapid-acting insulin for glucose >150 mg/dL: give 1 unit for every 50 mg/dL above 150 mg/dL (150-200 mg/dL = 1 unit; 201-250 mg/dL = 2 units) 3
• If glycemic control remains suboptimal with once-daily morning NPH alone, consider splitting the dose (2/3 morning, 1/3 evening) or adding prandial insulin coverage 1, 2