How to titrate insulin glargine (glargine) 40 units once daily (OD) in a 72 kg patient with hyperglycemia (blood glucose 300-500 mg/dL) and also initiate premeal regular insulin (regular insulin) therapy?

Insulin Glargine Titration and Premeal Regular Insulin Initiation

Immediate Basal Insulin Titration

For a 72 kg patient with blood glucose 300-500 mg/dL on 40 units of insulin glargine, increase the dose by 4 units every 3 days until fasting glucose reaches 80-130 mg/dL, and simultaneously initiate premeal regular insulin at 4 units before the largest meal. 1

Aggressive Basal Insulin Adjustment

• Your patient requires aggressive titration given the severe hyperglycemia (300-500 mg/dL) 1
• Increase glargine by 4 units every 3 days when fasting glucose is ≥180 mg/dL 1, 2
• Continue this titration until fasting glucose consistently reaches 80-130 mg/dL 1, 2
• Monitor fasting blood glucose daily during this titration phase 2

Critical Threshold Monitoring

• Watch for overbasalization when your basal dose exceeds 0.5 units/kg/day (36 units for this 72 kg patient) 2
• Clinical signals of overbasalization include: basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 2
• When basal insulin approaches 0.5-1.0 units/kg/day (36-72 units) without achieving glycemic targets, adding prandial insulin becomes more appropriate than continuing to escalate basal insulin alone 1, 2

Initiating Premeal Regular Insulin

Starting Dose Calculation

• Start with 4 units of regular insulin before the largest meal 1, 2
• Alternatively, use 10% of the current basal dose (4 units based on 40 units glargine) 1, 2
• Regular insulin should be administered 30 minutes before meals, not 0-15 minutes like rapid-acting analogs 3

Prandial Insulin Titration

• Increase the premeal regular insulin dose by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 1, 2
• Target postprandial glucose <180 mg/dL 2
• If hypoglycemia occurs without clear cause, reduce the corresponding dose by 10-20% 1, 2

Sequential Meal Coverage

• If A1C remains elevated after optimizing one meal, add regular insulin before additional meals sequentially 4
• Start with the meal causing the greatest postprandial glucose excursion 1
• Each meal's insulin dose should be titrated independently based on that meal's postprandial glucose 2

Foundation Therapy Considerations

• Continue metformin at maximum tolerated dose (up to 2000-2500 mg daily) unless contraindicated 2, 4
• Metformin combined with insulin reduces total insulin requirements, decreases weight gain, and lowers hypoglycemia risk compared to insulin alone 3, 5
• Discontinue sulfonylureas when implementing basal-bolus insulin regimens, as the combination significantly increases hypoglycemia risk 2, 4

Expected Insulin Requirements

• For severe hyperglycemia (glucose 300-500 mg/dL), total daily insulin requirements typically range from 0.3-0.5 units/kg/day 2, 4
• For this 72 kg patient, expect a total daily dose of approximately 22-36 units initially, split between basal and prandial insulin 2
• The current 40 units of glargine alone may already be approaching the threshold where prandial coverage becomes essential 2

Monitoring Requirements

• Check fasting blood glucose every morning to guide basal insulin adjustments 2
• Check pre-meal and 2-hour postprandial glucose to guide prandial insulin adjustments 2
• Reassess glycemic control every 3 days during active titration 1, 2
• Once stable, reassess every 3-6 months to evaluate overall control and HbA1c 2

Critical Pitfalls to Avoid

• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day (36-72 units) without addressing postprandial hyperglycemia, as this leads to overbasalization with increased hypoglycemia risk and suboptimal control 1, 2
• Do not use sliding scale insulin as monotherapy—it treats hyperglycemia reactively rather than preventing it, leading to dangerous glucose fluctuations 2, 4
• Do not delay adding prandial insulin when blood glucose levels are 300-500 mg/dL, as this clearly indicates the need for both basal and prandial coverage 2, 4
• Do not abruptly discontinue oral medications when intensifying insulin therapy—continue metformin unless contraindicated 2, 3

Patient Education Essentials

• Teach proper insulin injection technique and site rotation to prevent lipodystrophy 2, 6
• Provide education on hypoglycemia recognition and treatment with 15 grams of fast-acting carbohydrate 2
• Instruct on self-monitoring of blood glucose and "sick day" management rules 2
• Ensure understanding of insulin storage, handling, and the importance of administering regular insulin 30 minutes before meals 6, 3