What is the initial insulin order for a patient starting an insulin pump (insulin pump) with Novolog (insulin aspart) or Humalog (insulin lispro)?

Initial Insulin Order for Insulin Pump Therapy

For a patient starting insulin pump therapy with Novolog (insulin aspart) or Humalog (insulin lispro), order a 10mL vial (1000 units) of U-100 rapid-acting insulin analog, which provides sufficient supply for initial pump setup and approximately 10-30 days of therapy depending on total daily dose requirements.

Calculating Total Daily Dose (TDD)

The initial insulin requirement depends critically on diabetes type and clinical presentation:

Type 1 Diabetes

• Start with 0.5 units/kg/day as the total daily dose for metabolically stable patients 1, 2
• Approximately 50% should be programmed as basal delivery and 50% as bolus doses divided among meals 1, 3
• For a 70 kg patient: TDD = 35 units/day (17.5 units basal, 17.5 units bolus) 1
• Patients in the honeymoon phase may require lower doses of 0.2-0.6 units/kg/day 2
• Higher doses (>1.0 units/kg/day) are needed during puberty, pregnancy, or acute illness 2

Type 2 Diabetes

• Initial TDD typically ranges from 0.5-1.0 units/kg/day 4
• Basal delivery represents approximately 55% of TDD, with 45% as bolus in type 2 diabetes patients 4
• For a 90 kg patient with type 2 diabetes: TDD = 45-90 units/day 4

Pump Programming Parameters

Basal Rate Calculation

• Total basal dose = 0.48 × TDD (approximately 40-60% of total daily dose) 1, 3
• Most patients can be managed with two or fewer daily basal rates 4
• Divide the total basal dose by 24 hours to determine the hourly basal rate 3
• Example: If TDD = 50 units, basal = 24 units/day = 1.0 unit/hour 3

Bolus Dosing Parameters

• Carbohydrate-to-insulin ratio (CIR) = 2.8 × body weight in pounds / TDD 3
• Insulin sensitivity factor (correction factor) = 1700/TDD for rapid-acting analogs 1, 3
• Example: For TDD of 50 units, correction factor = 1700/50 = 34 mg/dL per unit 3

Practical Ordering Considerations

Insulin Supply Calculation

• A 10mL vial contains 1000 units of U-100 insulin 5
• For a patient using 50 units/day, one vial provides 20 days of therapy 5
• Order 2-3 vials initially to ensure adequate supply during dose titration 5

Pump-Specific Requirements

• Insulin pumps use only rapid-acting insulin analogs (Novolog, Humalog, or Apidra) - never use long-acting insulin in pumps 5
• Tubed pumps require insulin cartridges or reservoirs that hold 180-300 units 5
• Patch pumps (tubeless) typically hold 200 units 5
• Plan for cartridge/reservoir changes every 2-3 days 5

Critical Pitfalls to Avoid

• Never dilute or mix rapid-acting insulin analogs with other insulins or solutions when loading pump reservoirs 1
• Do not use the same insulin dosing as previous injection therapy - pump therapy typically requires 20-25% less total daily insulin due to improved absorption 6
• Patients previously on excessive insulin doses (>0.6 units/kg/day) often require significant dose reductions when transitioning to pump therapy 6
• Avoid using premixed insulins in pump therapy - pumps require only rapid-acting analogs 2

Monitoring During Initiation

• Check blood glucose every 2-4 hours during the first 24-48 hours of pump therapy 5
• Adjust basal rates by 10-20% if hypoglycemia occurs 1
• Increase basal rates by 0.1-0.2 units/hour if fasting glucose remains elevated 1
• Reassess pump settings every 3-7 days until glycemic targets are achieved 1

Special Clinical Situations

Transitioning from IV Insulin

• Total subcutaneous dose = 1/2 of IV insulin infused over 24 hours 1
• Give half as basal delivery and divide the remaining half among three meals 1

Hospitalized Patients

• For insulin-naive patients, start with 0.3-0.5 units/kg/day as TDD 1
• Reduce home insulin dose by 20% for patients on high-dose insulin (≥0.6 units/kg/day) to prevent hypoglycemia 1, 2

Patients with Renal Failure or Poor Oral Intake

• Use lower doses of 0.1-0.25 units/kg/day for high-risk patients including elderly (>65 years) 1, 2