What is the recommended Lantus dose, carb ratio, and correction scale for a 42-year-old male with type 2 diabetes, HbA1c 10.4%, GFR >90, and non-adherent to Mounjaro and glipizide, with a fasting glucose of 142 mg/dL?

Insulin Dosing and Discharge Plan for Type 2 Diabetes with Severe Hyperglycemia

Immediate Insulin Regimen

For this 42-year-old male (87 kg) with HbA1c 10.4% and medication non-adherence, initiate basal-bolus insulin therapy immediately rather than basal insulin alone, given the severity of hyperglycemia. 1, 2

Lantus (Basal Insulin) Dosing

• Start Lantus at 17-26 units once daily (0.2-0.3 units/kg/day for 87 kg patient) 2, 1
• Administer at the same time each day, typically at bedtime 2
• For severe hyperglycemia with HbA1c >10%, use the higher end of the starting range (0.3 units/kg = 26 units) 2, 1

Prandial Insulin Coverage

• Start with 4-6 units of rapid-acting insulin (Humalog, Novolog, or Apidra) before each of the three largest meals 2, 1
• Administer 0-15 minutes before eating 2
• This represents approximately 50% of total daily dose split among meals 2

Titration Protocol

Basal Insulin Adjustment

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

Prandial Insulin Adjustment

• Increase prandial insulin by 1-2 units every 3 days based on 2-hour postprandial glucose readings 2
• Target postprandial glucose <180 mg/dL 1, 2

Correction Scale (Insulin Sensitivity Factor)

Use a simplified correction scale as adjunct to scheduled doses:

• Add 2 units of rapid-acting insulin if pre-meal glucose >250 mg/dL 2
• Add 4 units of rapid-acting insulin if pre-meal glucose >350 mg/dL 2

For more precise correction dosing, calculate insulin sensitivity factor (ISF):

• ISF = 1500 ÷ Total Daily Dose 2
• Example: If total daily dose is 50 units, ISF = 1500 ÷ 50 = 30 mg/dL per unit 2

Carbohydrate Ratio

Starting insulin-to-carbohydrate ratio: 1 unit per 10-15 grams of carbohydrate 2

Calculate more precisely using:

• 450 ÷ Total Daily Dose for rapid-acting insulin 2
• Example: If total daily dose is 50 units, ratio = 450 ÷ 50 = 1 unit per 9 grams carbohydrate 2

Critical Threshold Monitoring

Watch for overbasalization when Lantus exceeds 0.5 units/kg/day (43 units for this patient):

• Clinical signals include 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 without achieving targets, intensify prandial insulin rather than continuing to escalate basal insulin 1, 2

Foundation Therapy

Restart and optimize metformin immediately:

• Increase to at least 1000 mg twice daily (2000 mg total daily), maximum 2550 mg/day 2, 1
• Metformin must continue when adding insulin unless contraindicated (GFR >90 supports full dosing) 1, 2
• This combination reduces total insulin requirements and provides superior glycemic control 2

Discontinue glipizide permanently:

• Sulfonylureas should be stopped when starting basal-bolus insulin to prevent hypoglycemia 1, 2

Consider restarting Mounjaro (tirzepatide) after insulin stabilization:

• Tirzepatide added to basal insulin produces HbA1c reductions of 2.1-2.4% with significant weight loss 3, 4
• In SURPASS-5, tirzepatide 10-15 mg weekly added to insulin glargine reduced HbA1c by 2.34-2.40% vs 0.86% with placebo 3
• This combination may allow eventual insulin dose reduction while maintaining glycemic control 5, 3

Monitoring Requirements

Daily glucose monitoring during titration:

• Check fasting glucose every morning 2
• Check pre-meal glucose before each meal 2
• Check 2-hour postprandial glucose to guide prandial insulin adjustments 2

Follow-up schedule:

• Reassess every 3 days during active titration 2
• Check HbA1c every 3 months during intensive titration 2
• Once stable, reassess every 3-6 months 2

Patient Education Essentials

Hypoglycemia management:

• Treat any glucose <70 mg/dL immediately with 15 grams of fast-acting carbohydrate 2
• Recheck in 15 minutes and repeat if needed 2
• Always carry fast-acting carbohydrate source 2

Injection technique:

• Proper insulin injection technique and site rotation 2
• Never mix Lantus with other insulins 2
• Administer rapid-acting insulin 0-15 minutes before meals 2

Sick day management:

• Never stop basal insulin even with poor oral intake 2
• Check glucose more frequently during illness 2
• Contact provider if glucose consistently >250 mg/dL 2

Critical Pitfalls to Avoid

Never delay insulin intensification with HbA1c 10.4%:

• This level of hyperglycemia warrants immediate basal-bolus therapy, not basal insulin alone 1, 2
• Sliding scale insulin as monotherapy is explicitly condemned and ineffective 2

Never discontinue metformin when starting insulin:

• This leads to higher insulin requirements and more weight gain 2
• Metformin provides complementary glucose-lowering effects 2

Never continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia:

• This causes overbasalization with increased hypoglycemia risk and suboptimal control 1, 2

Address medication adherence barriers:

• The 2-month gap in medication use suggests significant adherence issues that must be addressed 1
• Consider fixed-dose combinations to reduce prescription burden 1
• Provide written instructions and involve family support if available 1

Expected Outcomes

With appropriate basal-bolus therapy:

• HbA1c reduction of 3-4% achievable over 3-6 months 2
• 68-90% of patients achieve HbA1c <7% with proper insulin intensification 2, 3
• Adding tirzepatide to insulin regimen can produce additional 1.5-2.4% HbA1c reduction 3