What is the appropriate dose of Actrapid (insulin) for a patient with hyperglycemia (elevated blood glucose level of 391 mg/dL) before lunch?

Correction Insulin Dosing for Pre-Lunch Blood Glucose of 391 mg/dL

For a pre-lunch blood glucose of 391 mg/dL, administer correction insulin using a correction factor (insulin sensitivity factor) calculated as 1800 divided by total daily insulin dose, which will lower blood glucose by approximately 50 mg/dL per unit of rapid-acting insulin in most patients. 1

Calculating the Correction Dose

Step 1: Determine Your Correction Factor (Insulin Sensitivity Factor)

• Use the 1800 rule: Divide 1800 by your total daily insulin dose (TDD) to determine how many mg/dL one unit of rapid-acting insulin will lower blood glucose 2
• For example, if TDD is 30 units: 1800 ÷ 30 = 60 mg/dL drop per unit
• If TDD is 40 units: 1800 ÷ 40 = 45 mg/dL drop per unit 2

Step 2: Calculate Units Needed for Correction

• Target pre-meal glucose: 80-130 mg/dL 1, 3
• Current glucose: 391 mg/dL
• Glucose above target: 391 - 130 = 261 mg/dL excess
• Correction dose = 261 ÷ (your correction factor)
  • Example with 60 mg/dL per unit: 261 ÷ 60 = approximately 4-5 units
  • Example with 45 mg/dL per unit: 261 ÷ 45 = approximately 6 units 1

Step 3: Add Mealtime Insulin (If Applicable)

• If this patient normally takes mealtime insulin with lunch, add the correction dose to the usual meal dose 1
• If no established meal insulin regimen exists, give correction dose alone and reassess in 2-3 hours 1

Critical Context-Dependent Adjustments

For Hospitalized Patients with Severe Hyperglycemia

• Blood glucose >300 mg/dL indicates need for basal-bolus regimen, not just correction doses 1
• Start total daily dose of 0.3-0.4 units/kg/day, with 50% as basal and 50% divided among meals 1
• Give correction insulin every 4-6 hours using rapid-acting insulin until basal-bolus regimen is established 1

For Outpatients on Established Insulin Regimens

• If basal insulin dose exceeds 0.5 units/kg/day and pre-meal glucose remains this elevated, the patient likely needs prandial insulin added or increased, not just more basal insulin 1
• Common pitfall: Continuing to escalate basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia leads to overbasalization and increased hypoglycemia risk 1

For Insulin-Naive Patients

• A glucose of 391 mg/dL suggests need for insulin initiation, not just correction 1
• Start basal insulin at 0.2-0.3 units/kg/day plus correction doses with rapid-acting insulin before meals 1

Timing and Type of Insulin

• Use rapid-acting insulin (Actrapid/regular insulin) given 15-30 minutes before the meal 1
• Recheck blood glucose 2-3 hours post-dose to assess response 1, 3
• If using regular insulin instead of rapid-acting analogs, allow 30 minutes before eating and expect longer duration of action 1

Safety Considerations

• Avoid stacking: If correction insulin was given within the past 3-4 hours, reduce the correction dose by 50% to prevent hypoglycemia 1
• Monitor for hypoglycemia 2-4 hours after correction dose 1
• If patient has reduced oral intake, reduce or withhold prandial insulin but continue correction insulin at reduced dose 1
• In elderly or frail patients with hypoglycemia risk, target higher pre-meal glucose (100-150 mg/dL) and use more conservative correction factors 1