Blood Glucose 89-90 mg/dL Overnight on Lantus 20 Units: Dose Adjustment Needed
Your current Lantus dose of 20 units is appropriate and should NOT be reduced, as overnight blood glucose levels of 89-90 mg/dL fall within the optimal target range of 80-130 mg/dL recommended by the American Diabetes Association. 1
Why This Dose is Appropriate
Your fasting glucose values are exactly where they should be:
- Target fasting glucose range: 80-130 mg/dL 1
- Your values of 89-90 mg/dL sit comfortably in the middle of this range
- These readings indicate your basal insulin is properly titrated 1
When to Reduce Lantus Dose
The American Diabetes Association provides clear criteria for dose reduction:
- Reduce by 2 units only if more than 2 fasting glucose values per week are LESS than 80 mg/dL 1
- Your readings of 89-90 mg/dL do not meet this threshold
- If you experience hypoglycemia (glucose <70 mg/dL) without clear cause, reduce dose by 10-20% immediately 1
Critical Monitoring Points
Continue checking your fasting glucose daily and watch for these warning signs:
- Hypoglycemia symptoms: shakiness, sweating, confusion, or glucose readings <70 mg/dL 1
- Nocturnal hypoglycemia: night sweats, nightmares, morning headaches 1
- If either occurs, reduce your Lantus dose by 10-20% and contact your healthcare provider 1
When to Increase Your Dose
If your situation changes, consider dose adjustment:
- Increase by 2 units every 3 days if fasting glucose is 140-179 mg/dL 1
- Increase by 4 units every 3 days if fasting glucose is ≥180 mg/dL 1
- Continue titration until fasting glucose consistently reaches 80-130 mg/dL 1
Important Caveats
Do not make changes based on single readings. The American Diabetes Association recommends assessing glucose patterns over several days, not reacting to individual values 1. Your consistent readings of 89-90 mg/dL represent stable, well-controlled fasting glucose.
Maintain consistent timing. Administer Lantus at the same time each day to maintain stable blood glucose levels 2, 3. Changes in injection timing can affect glycemic control 3.