Hyperglycemia Management for CBG 249 mg/dL
Direct Answer
For a capillary blood glucose of 249 mg/dL in an adult without significant renal impairment and not on insulin, you should NOT give regular insulin as a one-time correction dose. Instead, initiate a scheduled basal insulin regimen starting with 10 units of long-acting insulin (such as insulin glargine) once daily, or calculate 0.1-0.2 units/kg body weight once daily 1, 2.
Why Correction Insulin Alone is Inappropriate
- Sliding scale insulin as monotherapy is explicitly condemned by all major diabetes guidelines and leads to dangerous glucose fluctuations rather than preventing hyperglycemia 1.
- A CBG of 249 mg/dL indicates chronic hyperglycemia requiring scheduled basal insulin therapy, not reactive correction doses 1.
- Correction insulin should only be used as an adjunct to scheduled basal-bolus therapy, never as the sole treatment 1.
Recommended Insulin Regimen
Initial Basal Insulin Dosing
- Start with 10 units of basal insulin (glargine, detemir, or degludec) once daily at the same time each day 1, 2.
- Alternatively, calculate 0.1-0.2 units/kg body weight once daily for the initial dose 1, 2.
- For patients with more severe hyperglycemia (HbA1c ≥9% or blood glucose ≥300-350 mg/dL), consider higher starting doses of 0.3-0.4 units/kg/day 1.
Titration Protocol
- Increase basal insulin 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.
- Target fasting plasma glucose of 80-130 mg/dL 1.
- If hypoglycemia occurs without clear cause, reduce the dose by 10-20% immediately 1.
Foundation Therapy
- Continue metformin unless contraindicated when initiating insulin therapy, as this combination provides superior glycemic control with reduced insulin requirements and less weight gain 1.
- Consider continuing one additional non-insulin agent 1.
If Correction Insulin is Needed (As Adjunct Only)
If you must provide correction insulin alongside scheduled basal therapy:
- Use a simplified approach: 2 units of rapid-acting insulin for glucose >250 mg/dL, and 4 units for glucose >350 mg/dL 1.
- The insulin sensitivity factor (correction factor) can be calculated as 1500 ÷ total daily dose of insulin 1.
- Never give rapid-acting insulin at bedtime, as this significantly increases nocturnal hypoglycemia risk 1.
Critical Threshold to Monitor
- When basal insulin exceeds 0.5 units/kg/day and approaches 1.0 units/kg/day, add prandial insulin rather than continuing to escalate basal insulin alone 1.
- Signs of "overbasalization" include basal dose >0.5 units/kg/day, bedtime-to-morning glucose differential ≥50 mg/dL, hypoglycemia, and high glucose variability 1.
Monitoring Requirements
- Daily fasting blood glucose monitoring is essential during titration 1.
- Reassess every 3 days during active titration 1.
- Check HbA1c every 3 months during intensive titration 1.
Common Pitfalls to Avoid
- Never use sliding scale insulin as monotherapy—this treats hyperglycemia reactively after it occurs rather than preventing it 1.
- Never delay insulin initiation in patients not achieving glycemic goals, as this prolongs exposure to hyperglycemia and increases complication risk 1.
- Never discontinue metformin when starting insulin unless contraindicated, as this leads to higher insulin requirements and more weight gain 1.