What adjustments should be made to an inpatient's current insulin regimen, using 8 units of lispro (Humalog) and 9 units of glargine (Lantus), to manage their diabetes and prevent hyperglycemia or hypoglycemia?

Inpatient Insulin Dose Calculation

For this hospitalized patient using 8 units of lispro and 9 units of glargine in the last 24 hours, increase the total daily dose to approximately 25-30 units, split as 12-15 units glargine once daily and 4-5 units lispro before each meal.

Calculate Total Daily Dose (TDD)

• The current TDD is 17 units (8 units lispro + 9 units glargine), which is insufficient for adequate glycemic control in most hospitalized patients 1
• For hospitalized patients who are insulin-naive or on low-dose insulin, guidelines recommend starting with 0.3-0.5 units/kg as TDD, with half as basal insulin 1
• The current regimen suggests inadequate dosing, as most hospitalized patients with diabetes require higher insulin doses to achieve target glucose of 140-180 mg/dL 2

Recommended Basal-Bolus Split

Use a 50:50 split between basal and prandial insulin for hospitalized patients:

• Basal insulin (glargine): Increase from 9 units to 12-15 units once daily, representing 50% of the new TDD 2, 1
• Prandial insulin (lispro): Divide the remaining 50% equally among three meals = 4-5 units before each meal 2, 1
• This 50:50 ratio is specifically recommended for hospitalized patients requiring basal-bolus therapy 2

Titration Protocol

• Adjust basal glargine every 3 days based on fasting glucose patterns, targeting 80-130 mg/dL 1
• Adjust prandial lispro by 1-2 units every 3 days based on 2-hour postprandial glucose, targeting <180 mg/dL 2, 1
• If fasting glucose ≥180 mg/dL, increase glargine by 4 units every 3 days 1
• If fasting glucose 140-179 mg/dL, increase glargine by 2 units every 3 days 1

Add Correction Insulin Protocol

• Implement a correction insulin protocol using lispro for premeal glucose >180 mg/dL, separate from scheduled doses 2
• Use simplified sliding scale: 2 units lispro for glucose >250 mg/dL, 4 units for glucose >350 mg/dL 1
• Never use sliding scale insulin as monotherapy—it must be adjunctive to scheduled basal-bolus therapy 2, 3

Monitoring Requirements

• Check point-of-care glucose before each meal and at bedtime for patients eating regular meals 2
• Target glucose range of 140-180 mg/dL for non-critically ill hospitalized patients 2
• More stringent goals of 110-140 mg/dL may be appropriate for selected patients if achievable without significant hypoglycemia 2

Critical Pitfalls to Avoid

• Never rely on sliding scale insulin alone—this approach leads to dangerous glucose fluctuations and worse outcomes than basal-bolus regimens 2, 3
• Never give rapid-acting insulin at bedtime—this significantly increases nocturnal hypoglycemia risk 2, 1
• If hypoglycemia occurs, reduce the corresponding insulin dose by 10-20% immediately 1
• For patients with poor oral intake, immediately reduce TDD by 50% and give primarily as basal insulin 2

Special Considerations

• For high-risk patients (elderly >65 years, renal failure, poor oral intake), use lower starting doses of 0.1-0.25 units/kg/day 2, 1
• Continue metformin unless contraindicated, as this reduces total insulin requirements 3
• Discontinue sulfonylureas when advancing to basal-bolus insulin to prevent hypoglycemia 1