Insulin Correction Scale for Prandial Insulin with Linagliptin
For patients on 4 units of prandial insulin three times daily with linagliptin, use a simplified correction scale: add 2 units of rapid-acting insulin for premeal glucose >250 mg/dL and 4 units for glucose >350 mg/dL. 1
Evidence-Based Correction Scale
The American Diabetes Association's 2024 Standards of Care provides specific guidance for correction insulin in patients on fixed-dose prandial regimens 1:
- For premeal glucose >250 mg/dL (>13.9 mmol/L): Give 2 units of short- or rapid-acting insulin 1
- For premeal glucose >350 mg/dL (>19.4 mmol/L): Give 4 units of short- or rapid-acting insulin 1
Important caveat: Stop using the sliding scale when it is not needed daily, as this indicates your basal regimen needs adjustment rather than continued correction doses 1.
Key Considerations with Linagliptin Combination
Hypoglycemia Risk Reduction
Linagliptin (a DPP-4 inhibitor) significantly reduces hypoglycemia risk when combined with insulin 2, 3, 4:
- When linagliptin is used as monotherapy or with metformin, hypoglycemia risk is very low (0-1.2%) 2
- However, when combined with insulin, there is still potential for hypoglycemia, though less than insulin alone 3, 4
- In long-term care studies, linagliptin with insulin resulted in only 3% hypoglycemia <70 mg/dL compared to 37% with insulin alone 4
Dosing Adjustments
Monitor for the need to reduce your fixed 4-unit doses 1:
- If you experience >2 premeal glucose values/week <90 mg/dL (<5.0 mmol/L), decrease your fixed insulin dose 1
- For any hypoglycemia without clear cause, lower the corresponding insulin dose by 10-20% 1
- Linagliptin does not require dose adjustment for renal or hepatic impairment 2
Titration Algorithm
Every 2 weeks, assess your premeal glucose patterns 1:
- Target: 90-150 mg/dL (5.0-8.3 mmol/L) before meals 1
- If 50% of premeal values are above goal over 2 weeks: Increase the fixed dose by 1-2 units or 10-15% 1
- If frequent low values: Decrease the dose as noted above 1
Critical Safety Points
Avoid Common Pitfalls
- Do not use rapid- or short-acting insulin at bedtime 1 - your bedtime dose should be basal insulin only if needed
- Be aware of drug interactions: Linagliptin efficacy may be limited with concurrent CYP3A4 or P-glycoprotein inducers like rifampin 2
- Consider initial secretagogue dose reduction: If you're also on sulfonylureas or meglitinides with linagliptin, these should be reduced to prevent hypoglycemia 2
When to Simplify Your Regimen
If you're using correction insulin daily, your regimen needs adjustment rather than continued corrections 1:
- Consider converting to a basal-bolus regimen with individualized carbohydrate ratios 1
- Alternatively, if your prandial doses are ≤10 units, consider discontinuing prandial insulin and optimizing linagliptin with other non-insulin agents 1
Monitoring Requirements
Check glucose before each meal and adjust accordingly 1:
- Pre-breakfast glucose guides breakfast insulin
- Pre-lunch glucose guides lunch insulin
- Pre-dinner glucose guides dinner insulin
- Apply correction scale based on these premeal values 1