My fasting blood glucose is 248 mg/dL while taking insulin glargine (Lantus) 42 units nightly; how many units should I increase the Lantus dose?

Lantus Dose Adjustment for Overnight Hyperglycemia

Increase your Lantus dose by 4 units (from 42 to 46 units) tonight, and continue increasing by 4 units every 3 days until your fasting blood glucose consistently reaches 80–130 mg/dL. 1

Immediate Dose Adjustment Protocol

Your fasting blood glucose of 248 mg/dL falls into the category requiring aggressive titration:

• When fasting glucose is ≥180 mg/dL, increase basal insulin by 4 units every 3 days until reaching the target range of 80–130 mg/dL 1
• At your current dose of 42 units, this represents approximately a 10% increase, which is within the recommended 10–15% adjustment range 1
• Continue this 4-unit increment every 3 days as long as your fasting glucose remains ≥180 mg/dL 1

Target and Monitoring

• Your target fasting glucose is 80–130 mg/dL 1
• Check your fasting blood glucose every morning during this titration phase to guide dose adjustments 1
• If you experience any blood glucose <70 mg/dL, immediately reduce your Lantus dose by 10–20% (approximately 4–8 units) and contact your provider 1

Critical Threshold Awareness

• When your Lantus dose approaches 0.5 units/kg/day (which varies by body weight), you may need to add mealtime insulin rather than continuing to increase basal insulin alone 1
• Signs you may need mealtime insulin include: basal dose >0.5 units/kg/day, large overnight glucose drop (≥50 mg/dL from bedtime to morning), episodes of hypoglycemia, or high glucose variability throughout the day 1
• At these thresholds, continuing to escalate Lantus beyond 0.5–1.0 units/kg/day without addressing post-meal hyperglycemia leads to increased hypoglycemia risk without improved control 1

Foundation Therapy Considerations

• Continue metformin at maximum tolerated dose (up to 2,000–2,550 mg/day) unless contraindicated, as this combination reduces total insulin requirements by 20–30% and provides superior glycemic control 1
• If you're not currently on metformin, discuss starting it with your provider 1

Safety Precautions

• Treat any glucose <70 mg/dL immediately with 15 grams of fast-acting carbohydrate, recheck in 15 minutes, and repeat if needed 1
• Always carry a source of fast-acting carbohydrates 1
• Never skip your Lantus dose entirely, even if you're not eating, as basal insulin suppresses liver glucose production independent of food intake 1

When to Contact Your Provider

• If fasting glucose remains >180 mg/dL after 2–3 weeks of titration 1
• If you experience any glucose <70 mg/dL 1
• If your Lantus dose exceeds 0.5 units/kg/day (calculate based on your weight in kg) without achieving fasting glucose targets 1
• If you develop symptoms such as nausea, vomiting, or abdominal pain with high blood sugars, as these may indicate ketones 1

Expected Outcomes

• With proper titration using this algorithm, approximately 68% of patients achieve mean glucose <140 mg/dL 1
• The 4-unit increment every 3 days for glucose ≥180 mg/dL is specifically designed to achieve target fasting glucose efficiently while minimizing hypoglycemia risk 1, 2