What is the appropriate initial dose of Lantus (insulin glargine), carbohydrate ratio, and correction scale for a 42-year-old male, 87kg, BMI 32, HbA1C 10.4%, not on diabetes medications, with a fasting blood glucose of 142mg/dL, and currently NPO?

Initial Insulin Dosing for Insulin-Naive Type 2 Diabetes with Severe Hyperglycemia

For this 42-year-old male (87 kg, BMI 32, HbA1c 10.4%, fasting glucose 142 mg/dL), start Lantus at 17-35 units once daily (0.2-0.4 units/kg/day), begin with a carbohydrate ratio of 1:10 (1 unit per 10 grams carbohydrate), and use a correction factor of 1:50 (1 unit lowers glucose by 50 mg/dL) with a target glucose of 125 mg/dL. 1, 2

Basal Insulin (Lantus) Dosing

Start with 17-35 units of Lantus once daily at bedtime. 1, 2

• The American Diabetes Association recommends 0.2-0.4 units/kg/day for patients with HbA1c ≥9% or severe hyperglycemia, which translates to 17-35 units for an 87 kg patient. 1, 2
• For this patient with HbA1c 10.4%, the higher end of this range (0.3-0.4 units/kg = 26-35 units) is more appropriate given the degree of hyperglycemia. 1, 2
• A conservative starting dose of 26 units once daily at bedtime balances efficacy with safety, particularly since the patient is currently NPO. 1, 2

Titration protocol: Increase by 4 units every 3 days if fasting glucose ≥180 mg/dL, or by 2 units every 3 days if fasting glucose 140-179 mg/dL, targeting fasting glucose 80-130 mg/dL. 1, 2

Prandial Insulin Coverage

This patient requires basal-bolus therapy from the outset, not basal insulin alone. 1, 2

• With HbA1c 10.4% and blood glucose ≥300-350 mg/dL range (implied by the severe hyperglycemia), the American Diabetes Association recommends immediate basal-bolus insulin rather than basal-only therapy. 1, 2
• Start with 4-6 units of rapid-acting insulin (Humalog, Novolog, or Apidra) before each of the three largest meals. 1, 2
• This represents approximately 10-15% of the basal dose or a fixed starting dose of 4 units per meal. 1, 2

Carbohydrate Ratio

Use an initial insulin-to-carbohydrate ratio of 1:10 (1 unit per 10 grams of carbohydrate). 1

• Calculate using the 450 rule: 450 ÷ Total Daily Dose (TDD). 1
• With an estimated TDD of 40-50 units (26 units basal + 12-18 units prandial), the ratio would be 450 ÷ 45 = 1:10. 1
• Adjust by 1-2 units every 3 days based on 2-hour postprandial glucose readings, targeting <180 mg/dL. 1, 2

Correction Scale (Insulin Sensitivity Factor)

Use a correction factor of 1:50 (1 unit lowers glucose by 50 mg/dL) with a target glucose of 125 mg/dL. 1

• Calculate using the 1500 rule: 1500 ÷ TDD = 1500 ÷ 45 = approximately 33, but round to 50 for safety in an insulin-naive patient. 1
• Correction dose formula: (Current glucose - 125) ÷ 50 = units of rapid-acting insulin to add to meal dose. 1
• For example, if pre-meal glucose is 225 mg/dL: (225 - 125) ÷ 50 = 2 units correction dose added to the carbohydrate coverage dose. 1

Simplified correction scale for nursing staff while NPO:

• Glucose 180-250 mg/dL: 2 units rapid-acting insulin 1
• Glucose 251-350 mg/dL: 4 units rapid-acting insulin 1
• Glucose >350 mg/dL: 6 units rapid-acting insulin and notify physician 1

Critical Considerations for NPO Status

While the patient remains NPO, hold prandial insulin and use only correction doses with basal insulin. 1, 2

• Continue Lantus at the prescribed dose even with NPO status, as basal insulin addresses fasting glucose and hepatic glucose production, not meal coverage. 1, 2
• Use correction doses of rapid-acting insulin every 4-6 hours for glucose >180 mg/dL using the simplified scale above. 1, 2
• Once oral intake resumes, implement the full basal-bolus regimen with carbohydrate counting and correction doses before meals. 1, 2

Monitoring Requirements

• Check fasting glucose daily and pre-meal glucose before each meal once eating resumes. 1, 2
• Check 2-hour postprandial glucose after the largest meal to guide prandial insulin adjustments. 1, 2
• While NPO, check glucose every 4-6 hours. 1, 2
• If any glucose <70 mg/dL occurs, reduce the corresponding insulin dose by 10-20% immediately. 1, 2

Foundation Therapy

Start metformin 500-1000 mg twice daily (up to 2000 mg/day) once oral intake resumes, unless contraindicated. 1, 2

• Metformin should be continued when initiating insulin therapy, as the combination provides superior glycemic control with reduced insulin requirements and less weight gain. 1, 2
• The combination of basal-bolus insulin with metformin is particularly effective for severe hyperglycemia. 1, 2

Critical Threshold Warning

When basal insulin exceeds 0.5 units/kg/day (44 units for this patient) without achieving glycemic targets, intensify prandial insulin rather than continuing to escalate basal insulin alone. 1, 2

• Signs of "overbasalization" include basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability. 1, 2
• At this threshold, increase prandial insulin doses by 1-2 units every 3 days rather than further increasing Lantus. 1, 2

Expected Outcomes

• HbA1c reduction of 3-4% from baseline (10.4% to 6.4-7.4%) over 3-6 months with appropriate basal-bolus therapy. 1, 2
• Target fasting glucose 80-130 mg/dL and postprandial glucose <180 mg/dL. 1, 2
• Reassess HbA1c every 3 months until target is achieved. 1, 2