Calculating Glargine Dose for DKA Recovery
Administer glargine at 0.3 units/kg subcutaneously 2-4 hours before stopping IV insulin infusion to prevent rebound hyperglycemia and recurrent DKA. 1, 2
Timing of Glargine Administration
The critical element is overlap timing between IV and subcutaneous insulin:
- Give the first glargine dose 2-4 hours before discontinuing IV insulin to ensure adequate basal coverage and prevent metabolic decompensation 1, 3
- Never stop IV insulin before administering subcutaneous basal insulin, as this causes rebound hyperglycemia and recurrent DKA 1
- Recent evidence demonstrates that early co-administration of glargine during IV insulin infusion (while still treating active DKA) significantly reduces time to DKA resolution from 11.12 hours to 6.33-6.78 hours without increasing hypoglycemia risk 2
Dose Calculation Methods
Method 1: Weight-Based Dosing (Preferred for Initial Transition)
Start with 0.3 units/kg once daily for the initial glargine dose 2
- For metabolically stable patients after DKA resolution: 0.5 units/kg/day total daily dose, with 50% given as basal insulin 1
- For patients with ongoing metabolic stress or infection: may require 0.5-0.65 units/kg/day as basal insulin alone 4, 1
- Example: For a 77 kg patient, initial glargine dose = 40-50 units once daily 4, 1
Method 2: Based on IV Insulin Requirements
Calculate total daily dose from average IV insulin rate over the last 12 hours × 24, then give 50% as basal insulin 1
- Example: If IV insulin averaged 4 units/hour for 12 hours → Total daily dose = 4 × 24 = 96 units → Glargine dose = 48 units 1
- This method accounts for individual insulin sensitivity during acute illness 1
Complete Insulin Regimen After DKA Resolution
Once DKA is resolved (glucose <200 mg/dL, bicarbonate ≥18 mEq/L, pH >7.3, anion gap ≤12), transition to basal-bolus regimen: 1, 3
- Basal insulin (glargine): 50% of total daily dose, given once daily 1, 3
- Prandial insulin (rapid-acting): 50% of total daily dose, divided equally before three meals 1, 3
- Starting carbohydrate ratio: 1:10 (1 unit per 10 grams of carbohydrate) 4, 1
- Correction factor: 1 unit lowers glucose by 50 mg/dL, targeting 100-150 mg/dL 4, 1
Critical Safety Considerations
Electrolyte monitoring is essential:
- Check potassium before starting any insulin therapy; delay if K+ <3.3 mEq/L to prevent fatal arrhythmias 1
- Early glargine administration is associated with increased hypokalemia risk (OR 3.4), requiring vigilant potassium monitoring and replacement 5
- Add 20-30 mEq potassium per liter IV fluid once K+ is 3.3-5.5 mEq/L 1
Avoid correction-only (sliding scale) insulin:
- Never use sliding scale insulin alone without basal coverage, as this leads to worse outcomes and higher complication rates 1, 3
- A basal-bolus regimen with glargine and rapid-acting insulin results in lower hypoglycemia rates (15% vs 41%) compared to NPH/regular insulin 3
Medication Adjustments During DKA
- Discontinue SGLT2 inhibitors immediately and do not restart until infection resolved and metabolically stable 1
- Hold metformin during acute illness; restart once stable and eating normally 1
Monitoring and Titration
After initial glargine dose: 4
- Increase by 2-4 units every 3 days if fasting glucose >130 mg/dL 4
- Adjust carbohydrate ratios if postprandial glucose consistently >180 mg/dL 4
- Tighten correction factor to 1:40 if corrections are ineffective 4
Both glargine U100 and U300 formulations demonstrate equivalent efficacy and safety when used at 0.3 units/kg during DKA management, with no significant differences in time to resolution or complication rates 2