Insulin Dosing Guidelines for Adults with Diabetes Mellitus
Introduction to Insulin Regimens
- The American Diabetes Association recommends starting with basal insulin at 50% of total daily dose (TDD) given once daily, combined with rapid-acting insulin analogs before each meal comprising the remaining 50% of TDD, using an insulin-to-carbohydrate ratio and correction factor for premeal dosing 1
Basal Insulin Dosing Considerations
- The American Association of Clinical Endocrinologists suggests using a long-acting insulin analog (glargine U-100/U-300, detemir, or degludec) administered once daily, typically comprising 40-60% of total daily insulin dose 1
- Administer basal insulin at the same time each day, as morning administration reduces nocturnal hypoglycemia risk 2
Premeal Insulin Dosing Strategies
- The Endocrine Society recommends using ultra-rapid-acting (URAA) or rapid-acting analogs (RAA) such as lispro, aspart, or glulisine before each meal, comprising 40-50% of total daily dose, distributed across three meals 1
- Calculate premeal insulin doses using insulin-to-carbohydrate ratio (ICR) plus correction doses based on insulin sensitivity factor (ISF) and target glucose 1
Supplemental Correction Dosing Approaches
- For premeal glucose >250 mg/dL (>13.9 mmol/L), add 2 units of rapid-acting insulin, and for premeal glucose >350 mg/dL (>19.4 mmol/L), add 4 units of rapid-acting insulin 3
- Target premeal glucose of 90-150 mg/dL (5.0-8.3 mmol/L) 3
Critical Safety Considerations for Insulin Therapy
- Never use rapid- or short-acting insulin at bedtime to avoid nocturnal hypoglycemia 2
- Avoid using only sliding scale insulin without basal coverage, as this leads to poor glycemic control 3
- Don't mix rapid-acting analogs with basal insulin in the same syringe 1
Regimen Selection and Adjustment
- For a 39-year-old, the multiple daily injection (MDI) regimen with long-acting basal analog plus flexible rapid-acting analog at meals is the standard of care, providing flexibility in meal timing and content, and reduced hypoglycemia compared to older regimens 1
- At least 4 daily injections are required (1 basal + 3 premeal) 1