Insulin Adjustment for Overnight Blood Glucose of 76 mg/dL
Reduce your Lantus dose by 2-4 units (from 20 units to 16-18 units) to prevent nocturnal hypoglycemia, as a blood glucose of 76 mg/dL overnight is approaching the threshold for hypoglycemia and indicates your basal insulin is slightly excessive. 1
Understanding the Current Situation
Your overnight blood glucose of 76 mg/dL is technically within normal range but sits at the lower end, creating risk for nocturnal hypoglycemia. This is particularly concerning because:
- Nocturnal hypoglycemia is dangerous - You may not recognize symptoms while sleeping, and hypoglycemia unawareness can develop from repeated episodes, further increasing your risk for severe hypoglycemia 1
- The goal is to maintain fasting glucose between 80-130 mg/dL - Your current level of 76 mg/dL leaves minimal margin for error and suggests your basal insulin dose is slightly too high 1
Specific Basal Insulin Adjustment
Decrease Lantus by 2-4 units immediately:
- Reduce from 20 units to 16-18 units administered at the same time each evening 1
- Monitor fasting blood glucose for 3-4 consecutive days after the adjustment to assess the new dose 1
- Target fasting glucose of 100-130 mg/dL provides a safer buffer against nocturnal hypoglycemia while maintaining good glycemic control 1
The rationale: In type 1 diabetes, basal insulin should provide steady background coverage without causing hypoglycemia during fasting periods. Your overnight glucose trending toward 76 mg/dL indicates the current 20 units is slightly excessive for your weight (72 kg) and metabolic needs 2.
Monitoring Strategy During Adjustment
- Check blood glucose at bedtime and upon waking for at least one week after dose reduction 1
- Set an alarm to check blood glucose at 3 AM for 2-3 nights to ensure you're not experiencing unrecognized nocturnal hypoglycemia 1
- Keep glucose tablets or 15-20 grams of fast-acting carbohydrate at your bedside in case of hypoglycemia 1
Your Carbohydrate Ratio Appears Appropriate
Your 1:10 carbohydrate ratio (1 unit per 10 grams of carbohydrate) is reasonable for your weight and should be maintained unless you experience post-meal hyperglycemia or hypoglycemia 1, 3. The issue here is specifically with basal insulin, not mealtime coverage.
Critical Safety Considerations
Common pitfall to avoid: Do not ignore borderline low overnight glucose values. Many patients and providers dismiss readings in the 70s as "acceptable," but in type 1 diabetes, this creates unnecessary hypoglycemia risk, especially during sleep when counterregulatory responses may be blunted 1.
If you experience any hypoglycemic symptoms overnight (sweating, palpitations, confusion upon waking, vivid dreams):
- Treat immediately with 15-20 grams of glucose (glucose tablets preferred, or any carbohydrate containing glucose) 1
- Recheck blood glucose in 15 minutes and repeat treatment if still below 70 mg/dL 1
- Further reduce Lantus by an additional 2 units the following evening 1
Weight and BMI Consideration
Your BMI of 19 indicates you are at the lower end of normal weight. This is relevant because:
- Lower body weight typically requires less insulin - Your total daily insulin needs are likely on the lower end of the typical 0.4-1.0 units/kg/day range for type 1 diabetes 1
- At 72 kg, your estimated total daily insulin requirement is approximately 29-72 units/day, with roughly 50% as basal insulin (14-36 units) 1
- Your current 20 units of Lantus falls within this range but may be at the higher end for your specific metabolism, as evidenced by the borderline low overnight glucose 2
When to Seek Further Adjustment
If after reducing Lantus to 16-18 units: