For an adult or adolescent with diabetic ketoacidosis, when can the insulin infusion be discontinued and how should the transition to subcutaneous basal (insulin glargine or detemir or NPH) and rapid‑acting (regular insulin, lispro or aspart) insulin be performed?

Stopping Insulin Infusion in Diabetic Ketoacidosis

Administer subcutaneous basal insulin (glargine or detemir) 2–4 hours before discontinuing the IV insulin infusion, then continue the IV infusion for an additional 1–2 hours after the basal dose to prevent rebound hyperglycemia and recurrent DKA. 1

Resolution Criteria Before Transition

You must confirm all of the following metabolic parameters are met simultaneously before initiating the transition:

• Glucose < 200 mg/dL (11.1 mmol/L) 1
• Serum bicarbonate ≥ 18 mEq/L 1
• Venous pH > 7.3 1
• Anion gap ≤ 12 mEq/L 1
• β-hydroxybutyrate < 1.0 mmol/L (if measured) 1
• Patient able to tolerate oral intake 1

Do not transition if any single criterion remains unmet; premature discontinuation of IV insulin is the most common cause of recurrent DKA. 1

Calculating the Subcutaneous Basal Insulin Dose

Standard Weight-Based Method

• Use 50% of the total 24-hour IV insulin dose as the initial subcutaneous basal insulin dose 1
• Example: If the patient received 6 U/h IV insulin for 24 hours (144 U total), give 72 U of glargine or detemir subcutaneously 1

Alternative Calculation for Stable Patients

• For metabolically stable patients after DKA resolution, start with 0.5 units/kg/day total daily insulin, allocating 50% as basal insulin 2
• For patients with ongoing infection or metabolic stress, doses up to 0.65–1.0 units/kg/day may be necessary 2

Timing Protocol (Critical)

Step 1: Administer the calculated basal insulin dose (glargine or detemir) subcutaneously 2–4 hours before you plan to stop the IV infusion 1

Step 2: Continue the IV insulin infusion at the current rate for 1–2 hours after the subcutaneous basal dose to allow adequate absorption 1

Step 3: Only then discontinue the IV insulin infusion 1

This overlap is mandatory—failure to overlap is the single most common error leading to DKA recurrence. 1

Initiating Prandial (Rapid-Acting) Insulin

Once the patient can eat, start a multiple-dose regimen:

• Prandial insulin: Use the remaining 50% of the total daily dose divided equally among three meals 1
• Example: If total daily dose is 144 U, give 24 U of lispro, aspart, or glulisine before each meal 1
• Administer rapid-acting insulin 0–15 minutes before meals 1

Alternative Prandial Dosing

• Start with 4 units before each meal or 10% of the basal dose per meal, then titrate based on post-prandial glucose 1

Monitoring During and After Transition

• Check blood glucose every 2–4 hours during the transition period 1
• Monitor serum potassium every 2–4 hours until stable, as insulin drives potassium intracellularly 1
• Target serum potassium 4.0–5.0 mEq/L throughout treatment 1
• Continue monitoring electrolytes, pH, bicarbonate, and anion gap every 2–4 hours until metabolically stable 1

Evidence for Early Basal Insulin Administration

Adding basal insulin during the IV infusion phase (before DKA resolution) accelerates ketoacidosis resolution and prevents rebound hyperglycemia:

• Co-administration of basal insulin with IV regular insulin results in faster resolution of acidosis without adverse effects 3
• Patients require a shorter duration of IV insulin infusion and a lower total IV insulin dose 3
• This approach significantly decreases hyperglycemia after IV insulin discontinuation 3
• Potential benefit: shorter ICU length of stay and reduced treatment costs 3
• Caution: This approach may increase the risk of hypokalemia—monitor potassium closely 3

Alternative Regimen After DKA Resolution

Glargine + glulisine is superior to NPH + regular insulin:

• Transition to glargine once daily + glulisine before meals results in similar glycemic control but a significantly lower rate of hypoglycemia compared to NPH + regular insulin 4
• In one randomized trial, 41% of patients on NPH/regular had hypoglycemic episodes versus 15% on glargine/glulisine (P = 0.03) 4
• A basal-bolus regimen with glargine and glulisine is safer and should be preferred after DKA resolution 4

Alternative Approach for Mild-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-moderate DKA (pH ≥ 7.0):

• Subcutaneous rapid-acting insulin analogs (lispro or aspart) every 1–2 hours combined with aggressive fluid management can be as effective as IV insulin 1, 5, 6
• This approach is more cost-effective and avoids ICU admission 1, 5
• Mean time to DKA resolution is similar between subcutaneous lispro (10–14.8 hours) and IV regular insulin (11–13.2 hours) 5
• Requirements: Patient must be hemodynamically stable, alert, have adequate fluid replacement, and receive frequent glucose monitoring 1

Pediatric Alternative

• Subcutaneous regular insulin every 4 hours is effective and safe for pediatric DKA with pH ≥ 7.0 7
• Median time to DKA resolution: 10.3 hours 7
• This simplifies insulin administration compared to IV or hourly subcutaneous dosing 7

Critical Pitfalls to Avoid

• Never stop IV insulin without prior basal insulin overlap—this is the most common cause of recurrent DKA 1
• Never transition before complete metabolic resolution—all criteria (glucose, pH, bicarbonate, anion gap) must be met simultaneously 1
• Never use sliding-scale insulin as monotherapy after DKA resolution—this approach is condemned by all major guidelines and leads to worse outcomes 2
• Do not delay potassium replacement—add 20–30 mEq/L to IV fluids once K+ is 3.3–5.5 mEq/L and urine output is adequate 2
• Never start insulin if serum potassium < 3.3 mEq/L—this can precipitate fatal cardiac arrhythmias 1

Special Considerations

SGLT2 Inhibitors

• Discontinue SGLT2 inhibitors immediately if the patient was taking them—they should have been stopped 3–4 days before any acute illness to prevent DKA 2
• Do not restart until the infection is resolved and the patient is metabolically stable 2

Metformin

• Hold metformin during acute illness and restart once stable and eating normally 2

Potassium Management

• Check potassium before starting insulin—delay insulin if K+ < 3.3 mEq/L 2
• Add 20–30 mEq potassium per liter of IV fluid once K+ is 3.3–5.5 mEq/L 2
• Target serum potassium 4–5 mEq/L throughout treatment 2
• Use a mixture of 2/3 potassium chloride (or acetate) and 1/3 potassium phosphate 1