What is a reasonable once daily insulin dosing regimen for a first-time user?

Once-Daily Insulin Dosing for First-Time Users

For a first-time insulin user requiring once-daily basal insulin, start with basal insulin (glargine, detemir, degludec, or NPH) administered once daily in the morning, with a fasting glucose goal of 90-150 mg/dL, titrating by 2 units every week based on fasting glucose values. 1

Recommended Basal Insulin Options

Long-acting basal insulins are the preferred choice for once-daily dosing:

• Insulin glargine (U-100 or U-300), detemir, degludec, or NPH insulin are all appropriate options 1
• These should be administered subcutaneously into the abdominal area, thigh, or deltoid 2
• Administer at the same time every day (morning administration is recommended for simplicity and to reduce nocturnal hypoglycemia risk) 1

Starting Dose Considerations

While the FDA label states dosing should be individualized 2, practical starting approaches include:

• In insulin-naive patients with type 2 diabetes, a common starting dose is 10 units once daily or 0.1-0.2 units/kg 3, 4
• The dose should be based on metabolic needs, blood glucose monitoring, and glycemic control 2

Titration Protocol

Follow this systematic approach for dose adjustment:

• Monitor fasting finger-stick glucose values over one week 1
• If 50% of fasting values are above goal (90-150 mg/dL): Increase dose by 2 units 1
• If more than 2 fasting values per week are <80 mg/dL: Decrease dose by 2 units 1
• Reassess every 1-2 weeks until fasting glucose targets are achieved 1

Critical Safety Considerations

Avoid these common pitfalls:

• Do not use rapid- or short-acting insulin at bedtime in first-time users or older adults (increased nocturnal hypoglycemia risk) 1
• Do not dilute or mix basal insulin with any other insulin or solution 2
• Rotate injection sites to reduce risk of lipodystrophy and localized cutaneous amyloidosis 2
• Use a syringe that has not been used for other insulin products 4

Monitoring Requirements

Essential glucose monitoring for safe titration:

• Self-monitoring of fasting blood glucose is required for dose adjustment 1
• Closely monitor glucose during the initial weeks after starting insulin 2
• Increase monitoring frequency if there are changes to insulin dosage, concomitant medications, meal patterns, or physical activity 2

When Once-Daily Basal Insulin Is Insufficient

If A1C remains above goal despite optimized basal insulin:

• Consider adding prandial (mealtime) insulin when basal insulin has been titrated to acceptable fasting glucose but A1C remains elevated 5
• Start prandial insulin at 4 units per dose, 0.1 units/kg, or 10% of the basal insulin dose with the largest meal 5, 6
• If adding prandial insulin and A1C is <8%, reduce basal insulin by 4 units or 10% to prevent hypoglycemia 5, 6

Special Population Considerations

For older adults or those at high hypoglycemia risk:

• Once-daily basal insulin is particularly appropriate due to minimal side effects and reduced complexity 1
• May adjust fasting glucose goal based on overall health status and goals of care (can be more liberal than 90-150 mg/dL) 1
• Consider morning administration rather than bedtime to reduce nocturnal hypoglycemia risk 1

Pharmacokinetic Advantages

Insulin glargine provides consistent 24-hour coverage:

• Precipitates in subcutaneous tissue after injection, providing slow, steady release 7, 8, 3
• Flat pharmacokinetic profile without pronounced peaks, mimicking physiologic basal insulin 7, 8, 3
• Duration of action approximately 24 hours with once-daily dosing 7, 8, 4
• Lower frequency of hypoglycemic reactions, especially nocturnal hypoglycemia, compared to NPH insulin 7, 8, 3