American Board of Family Medicine (ABFM) Practice Exam

The appropriate next step for a diabetic patient experiencing high glucose levels at night while currently on Lantus (insulin glargine) is to add rapid-acting insulin at dinner. High nighttime glucose levels, also referred to as "dawn phenomenon" or "somogyi effect," can occur due to inadequate basal insulin coverage or fluctuations in insulin sensitivity.

By adding rapid-acting insulin at dinner, the patient can better control the postprandial (after meal) blood glucose levels that subsequently impact fasting blood glucose levels. This approach helps address the glycemic spike that may occur overnight by providing additional insulin during the evening meal, which can help lower glucose levels before the patient goes to bed and improve overall glucose control throughout the night.

Increasing the nightly insulin glargine dose may seem like a potential solution; however, it may lead to increased risk of hypoglycemia in the night without necessarily addressing the immediate postprandial rise that occurs after dinner. Rapid-acting insulin at breakfast is generally less effective for controlling nighttime hyperglycemia since it addresses morning glucose levels rather than the overnight period. Also, increasing the insulin glargine dosage to two-thirds in the morning does not target the nighttime issue specifically, failing to provide the patient