BJ is an 80 kg newly diagnosed Type I insulin naive diabetic female that you plan to initiate a basal-bolus insulin regimen. You decide to initiate a total daily insulin dose of 0.5 units/kg/day. What should BJ's initial daily dose of insulin glargine (Lantus) be?

Rationale: A. To find the dose of insulin glargine, we first calculate the Total Daily Dose (TDD). TDD = 80 kg x 0.5 units/kg = 40 units per day. In a standard basal-bolus regimen, 50% of the TDD is administered as basal insulin, which is 20 units. This provides a constant background level of insulin to suppress hepatic glucose production between meals and during sleep. B. A dose of 80 units would be double the calculated TDD for this patient and would likely lead to severe, life-threatening hypoglycemia. This number incorrectly uses the patient's weight as the unit count rather than applying the prescribed 0.5 units/kg ratio. In clinical practice, initiating a naive patient on such an excessively high dose is a major medication safety violation that ignores physiological requirements. C. While 40 units represents the correct Total Daily Dose (TDD) for BJ, it is not the correct dose for the insulin glargine component alone. The TDD must be split between the long-acting basal insulin and the rapid-acting bolus insulin used for mealtime coverage. Giving the entire 40 units as glargine would leave no insulin for bolus requirements and would provide too much basal coverage, increasing fasting hypoglycemia risk. D. A dose of 10 units represents only 25% of the TDD, which is generally insufficient for the basal requirement of a Type 1 diabetic. Under-dosing basal insulin can lead to poor glycemic control and a higher risk of diabetic ketoacidosis (DKA) because the body lacks enough insulin to regulate lipolysis and gluconeogenesis. The 50/50 split between basal and bolus is the scientifically accepted starting point for naive patients.