What is the recommended insulin regimen for a patient with diabetes?

Insulin Cheat Sheet

Type 1 Diabetes: Basal-Bolus Regimen Required

Initial Dosing

• Start with 0.5 units/kg/day total daily dose (TDD), split 50% basal and 50% prandial insulin 1
• For a 70 kg patient: 35 units total = 17.5 units basal + 17.5 units prandial (divided among 3 meals: ~6 units each meal) 1
• Metabolically stable patients typically need 0.5 units/kg/day; range is 0.4-1.0 units/kg/day 1
• Higher doses needed during puberty, pregnancy, and acute illness (may exceed 1.0 units/kg/day) 1

Basal Insulin Options

• Glargine (Lantus): Give once daily at same time; may require twice-daily dosing if inadequate 24-hour coverage 1
• Detemir (Levemir): Often requires twice-daily dosing; total daily dose ~38% higher than glargine for equivalent control 1, 2
• Degludec (Tresiba): Once daily dosing 3

Prandial Insulin

• Rapid-acting analogs (lispro, aspart, glulisine): Give 0-15 minutes before meals 1, 4
• Regular insulin: Give 30-45 minutes before meals 3, 4
• Calculate using insulin-to-carbohydrate ratio: 450 ÷ TDD (for rapid-acting) or 500 ÷ TDD (for regular) 1
• Example: TDD 50 units → ICR = 450÷50 = 1:9 (1 unit per 9g carbs) 1

Correction Doses

• Insulin sensitivity factor (ISF) = 1500 ÷ TDD 1
• Example: TDD 50 units → ISF = 30 (1 unit lowers glucose by 30 mg/dL) 1
• Target preprandial glucose: 90-150 mg/dL 1

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Type 2 Diabetes: Start Basal, Add Prandial if Needed

Starting Basal Insulin (Insulin-Naive Patients)

• Start with 10 units once daily OR 0.1-0.2 units/kg/day 1
• For a 70 kg patient: 7-14 units once daily 1
• Continue metformin unless contraindicated 1
• Give at same time daily (bedtime or with evening meal) 1, 2

Titration Algorithm

• Target fasting glucose: 80-130 mg/dL 1
• If FG 140-179 mg/dL: increase by 2 units every 3 days 1
• If FG ≥180 mg/dL: increase by 4 units every 3 days 1
• If hypoglycemia occurs: reduce dose by 10-20% 1

Severe Hyperglycemia (A1C ≥9%, glucose ≥300 mg/dL)

• Start with 0.3-0.5 units/kg/day as basal-bolus regimen immediately 1
• For a 70 kg patient: 21-35 units total = ~50% basal + ~50% prandial 1

Critical Threshold: When to Add Prandial Insulin

• When basal insulin exceeds 0.5 units/kg/day without achieving A1C goal 1
• When fasting glucose is controlled but A1C remains elevated after 3-6 months 1
• Signs of overbasalization: bedtime-to-morning glucose drop ≥50 mg/dL, hypoglycemia, high glucose variability 1

Adding Prandial Insulin

• Start with 4 units rapid-acting insulin before largest meal OR 10% of basal dose 1
• Titrate by 1-2 units every 3 days based on 2-hour postprandial glucose 1
• Target postprandial glucose: <180 mg/dL 1

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Simplified Correction Insulin (Sliding Scale)

Use ONLY as adjunct to scheduled basal-bolus therapy, NEVER as monotherapy 1

• Premeal glucose >250 mg/dL: add 2 units rapid-acting 1
• Premeal glucose >350 mg/dL: add 4 units rapid-acting 1
• Never give rapid-acting insulin at bedtime (nocturnal hypoglycemia risk) 1

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Special Populations

Hospitalized Patients

• Insulin-naive or low-dose: Start 0.3-0.5 units/kg/day (50% basal, 50% bolus) 1
• High-dose home insulin (≥0.6 units/kg/day): Reduce by 20% on admission 1
• Elderly, renal failure, poor oral intake: Start 0.1-0.25 units/kg/day 1
• Target glucose: 140-180 mg/dL 1

Chronic Kidney Disease

• CKD Stage 5 with Type 2 DM: Reduce TDD by 50% 1
• CKD Stage 5 with Type 1 DM: Reduce TDD by 35-40% 1
• Monitor closely for hypoglycemia 1

Steroid-Induced Hyperglycemia

• Add 0.1-0.3 units/kg/day glargine to usual regimen 1
• Increase prandial/correction insulin by 40-60% 1
• Consider NPH in morning for daytime steroid effect 1

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Insulin Pump Therapy (Type 1 DM)

• Basal rate = 40-60% of TDD 1
• Bolus = 40-60% of TDD (divided among meals and corrections) 1
• ICR = 450 ÷ TDD 1
• ISF = 1500 ÷ TDD 1

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Premixed Insulin (70/30,75/25,50/50)

Type 2 Diabetes

• Start 10 units twice daily (before breakfast and dinner) OR 0.1-0.2 units/kg/day divided 1
• Titrate by 2-4 units every 3 days based on fasting and pre-dinner glucose 1
• Transition to basal-bolus when dose exceeds 0.5 units/kg/day without achieving A1C goal 1

Avoid in hospitalized patients (high hypoglycemia risk) 1

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Key Conversion Formulas

• Glargine to Detemir: Detemir dose = Glargine dose × 1.38 1
• IV to Subcutaneous: Subcutaneous TDD = ½ of 24-hour IV insulin 1
  • Give 50% as basal (evening), 50% as prandial (divided by 3) 1

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Critical Pitfalls to Avoid

• Never use sliding scale insulin as monotherapy 1
• Never discontinue metformin when starting insulin (unless contraindicated) 1
• Never continue escalating basal insulin beyond 0.5-1.0 units/kg/day without adding prandial coverage 1
• Never delay insulin initiation in patients not achieving glycemic goals 1
• Never give rapid-acting insulin at bedtime 1
• Never mix or dilute glargine with other insulins 1

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Hypoglycemia Management

• Treat glucose <70 mg/dL with 15g fast-acting carbohydrate 1
• Recheck in 15 minutes, repeat if needed 1
• If hypoglycemia occurs: reduce corresponding insulin dose by 10-20% 1

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Monitoring Requirements

• Daily fasting glucose during titration 1
• Pre-meal and 2-hour postprandial glucose when adjusting prandial insulin 1
• A1C every 3 months during intensive titration 1
• Reassess every 3-6 months once stable 1