What is the initial insulin dosage for a patient with hyperglycemia?

Initial Insulin Dosage for Hyperglycemia

For patients with marked hyperglycemia (blood glucose ≥250 mg/dL, A1C ≥8.5%) who are symptomatic with polyuria, polydipsia, nocturia, and/or weight loss, treatment should be initiated with basal insulin while metformin is simultaneously initiated and titrated. 1

Initial Dosing Algorithm Based on Clinical Presentation

For Non-Critically Ill Patients:

• Metabolically stable patients (A1C <8.5% and asymptomatic):

  • Metformin is the initial pharmacologic treatment of choice (if renal function is normal) 1
  • Insulin not required as first-line therapy

• Marked hyperglycemia (blood glucose ≥250 mg/dL, A1C ≥8.5%) with symptoms:

  • Initial basal insulin dosage: 0.2 units/kg or up to 10 units once daily 2
  • Simultaneously initiate metformin and titrate 1
  • Monitor blood glucose regularly to adjust insulin dose 1

• Ketosis/Ketoacidosis:

  • Initiate subcutaneous or intravenous insulin to rapidly correct hyperglycemia and metabolic derangement 1
  • Once acidosis resolves, initiate metformin while continuing subcutaneous insulin therapy 1

• Severe hyperglycemia (blood glucose ≥600 mg/dL):

  • Assess for hyperglycemic hyperosmolar nonketotic syndrome 1
  • Consider intravenous insulin infusion with close monitoring 1

For Critically Ill Patients:

• Initiate intravenous insulin infusion when blood glucose exceeds 180 mg/dL (10.0 mmol/L) 1
• Target glucose range: 140-180 mg/dL (7.8-10.0 mmol/L) 1
• Use established insulin infusion protocols with demonstrated safety and efficacy to minimize hypoglycemia risk 1

Insulin Adjustment and Titration

• If patients treated with basal insulin up to 1.5 units/kg/day do not meet A1C targets, transition to multiple daily injections with basal and premeal bolus insulins 1

• For patients initially treated with insulin and metformin who achieve glucose targets, insulin can be tapered over 2-6 weeks by decreasing the insulin dose by 10-30% every few days 1

• Home self-monitoring of blood glucose regimens should be individualized based on the pharmacologic treatment 1

Special Considerations

• Glucocorticoid-induced hyperglycemia:

  • Multiple-dose insulin therapy initiated at 1-1.2 U/kg per day (25% basal, 75% prandial) for patients receiving high-dose steroids 1, 3
  • For patients without pre-existing diabetes on steroids, isophane insulin (NPH) may be appropriate with a total dose of 0.3 units/kg per day (2/3 in morning, 1/3 in early evening) 1, 3

• Enteral/Parenteral nutrition:

  • For patients on enteral nutrition with hyperglycemia: basal insulin (isophane every 8h, detemir every 12h, or glargine every 24h) along with short-acting insulin every 4-6h 1
  • Start intravenous 10% dextrose infusion at 50 mL/h if tube feeding is interrupted 1

Common Pitfalls and Caveats

• Avoid sole use of sliding scale insulin in the inpatient hospital setting as it is strongly discouraged 1

• Beware of hypoglycemia risk when initiating insulin therapy, especially in patients with no prior insulin exposure 2

• Do not delay insulin therapy in patients not achieving glycemic goals, as prolonged hyperglycemia can worsen insulin resistance 4

• Consider the impact of high A1C levels on treatment approach - patients with A1C >10% may require more aggressive initial insulin dosing 1

• Monitor for rapid changes in insulin requirements when steroid doses are adjusted, as requirements can decline rapidly when steroids are discontinued 1