What is the appropriate initial dose of regular insulin (insulin) for a patient with hyperglycemia?

Subcutaneous Regular Insulin for Glucose 250 mg/dL

For a patient with glucose of 250 mg/dL without diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS), subcutaneous regular insulin can be administered as correctional (sliding scale) insulin at 5 units for every 50 mg/dL above 150 mg/dL, which would be 10 units for a glucose of 250 mg/dL. 1

Clinical Context Assessment

Before administering insulin, you must determine the clinical scenario:

• Check for DKA or HHS: Assess for symptoms (polyuria, polydipsia, weight loss), ketones, pH, and bicarbonate 2
• Exclude hypokalemia: Do not give insulin if K+ < 3.3 mEq/L 2
• Determine diabetes type and treatment status: This affects the insulin regimen choice 2

Dosing by Clinical Scenario

For Non-Critical Hyperglycemia (No DKA/HHS)

Correctional insulin dosing:

• Give 5 units subcutaneous regular insulin for every 50 mg/dL above 150 mg/dL 1
• For glucose 250 mg/dL: (250-150)/50 × 5 = 10 units subcutaneous regular insulin
• This can be repeated every 4-6 hours as needed 1

If initiating basal insulin therapy:

• Start at 10 units or 0.1-0.2 units/kg once daily, depending on degree of hyperglycemia 2
• For a 70 kg patient, this would be 7-14 units of basal insulin

For Youth with Marked Hyperglycemia (≥250 mg/dL) Without Acidosis

If symptomatic (polyuria, polydipsia, nocturia, weight loss):

• Initiate basal insulin while starting metformin 2
• Begin with basal insulin at standard starting doses (0.1-0.2 units/kg) 2

For DKA (Glucose >250 mg/dL with pH <7.3, bicarbonate <15 mEq/L)

Intravenous route is preferred over subcutaneous:

• IV bolus: 0.15 units/kg regular insulin 2
• Followed by continuous IV infusion: 0.1 units/kg/hour 2
• For a 70 kg patient: 10.5 unit bolus, then 7 units/hour infusion

Subcutaneous option for mild DKA:

• Can use subcutaneous regular insulin if DKA is mild 2
• Dosing follows similar weight-based calculations

For Hospitalized Non-Critical Patients

Target glucose range:

• 140-180 mg/dL for most hospitalized patients 2
• Initiate insulin therapy when glucose persistently ≥180 mg/dL 2

Basal-bolus regimen is preferred over sliding scale alone:

• More effective than sliding scale insulin for glycemic control 3
• Reduces hypoglycemia risk compared to premixed insulin 3

Critical Monitoring Points

After insulin administration:

• Recheck glucose in 1-2 hours to assess response 2
• Monitor for hypoglycemia, especially if patient is NPO or has reduced oral intake 2
• Ensure adequate hydration status 2

Common pitfalls to avoid:

• Do not give insulin if K+ < 3.3 mEq/L - this can cause life-threatening hypokalemia 2
• Do not use sliding scale alone as monotherapy - it provides inadequate glycemic control compared to scheduled basal-bolus regimens 3
• Do not delay insulin in symptomatic hyperglycemia - waiting for oral agents to work prolongs metabolic decompensation 2

Transition to Scheduled Insulin

If this is a new diagnosis or the patient requires ongoing insulin:

• Transition from correctional to scheduled insulin within 24-48 hours 2
• Use basal insulin (NPH, glargine, detemir, or degludec) as foundation 2
• Add prandial insulin if basal alone insufficient to reach A1C target 2
• Continue metformin if not contraindicated to reduce insulin requirements and weight gain 2, 4