Medicine>>>>>Endocrinology and Metabolic Disease
Question 16#

Your patient is a 48-year-old Hispanic man with a 4-year history of type 2 diabetes mellitus. He is currently utilizing NPH insulin/regular insulin 40/20 units prior to breakfast and 20/10 units prior to supper. His supper time has become variable due to a new job and ranges from 5 to 8 PM. In reviewing his glucose diary you note some very low readings (40-60 mg/dL) during the past few weeks at 3 AM. When he awakens to urinate, he feels sweaty or jittery so has been checking a fingerstick blood glucose. Morning glucose levels following these episodes are always higher (200-250) than his average fasting glucose level (120-150). Which change in his insulin regimen is most likely to resolve this patient’s early AM hypoglycemic episodes?

A. Increase morning NPH and decrease evening NPH
B. Decrease morning NPH and decrease evening regular insulin
C. Change regimen to glargine or detemir at bedtime and continue morning and evening regular insulin
D. Discontinue both NPH and regular insulin; implement sliding scale regular insulin with meals
E. Change regimen to glargine or detemir at bedtime with a rapid-acting insulin analogue (such as lispro, aspart, or glulisine) prior to each meal

Correct Answer is E

Comment:

To recognize the best insulin regimen, you must first understand the pharmacokinetics of different insulin preparation— namely the peak time of onset of action and effective duration. The following describes the insulin preparations from shortest to longest duration. Lispro (as well as the newer aspart and glulisine) has a peak onset of 0.5 to 1.5 hours and effective duration of 3 to 4 hours. Regular insulin has a peak onset of 2 to 3 hours and effective duration of 4 to 6 hours. NPH has a peak onset of 6 to 10 hours and effective duration of 10 to 16 hours. Glargine or detemir provides basal insulin with an effective duration of 24 hours and no peak effect. This patient is experiencing early morning hypoglycemia resulting from his erratic supper time; in addition his fasting blood glucose levels (120- 150 mg/dL) are not adequately controlled. The most appropriate insulin regimen for this patient is a long-acting insulin such as glargine at bedtime along with a short-acting insulin such as lispro before each meal. This will allow better regulation of basal glucose levels while providing coverage at mealtime and will address the issue of variable mealtimes. Twice-daily regimens with NPH and regular insulin have fallen out of favor as they rarely provide sufficient coverage for either basal or meal-associated glucose production. Although premeal regular insulin is cheaper, lispro more closely matches the meal-associated glucose surge and provides better overall control.