## **Core Concept**
The patient's blood glucose levels indicate a need for adjustment in her insulin regimen. The patient has insulin-dependent diabetes mellitus (IDDM) and is on a mixture of NPH insulin and crystalline zinc (Regular) insulin twice a day. The blood glucose levels provided are: before breakfast (115 mg/dl), before lunch (190 mg/dl), before dinner (135 mg/dl), and bedtime (185 mg/dl).

## **Why the Correct Answer is Right**
The patient's glucose levels suggest that she has **pre-lunch hyperglycemia** (190 mg/dl), which indicates that the morning dose of insulin is not lasting long enough to cover the glucose levels until lunch. The levels before breakfast (115 mg/dl) and before dinner (135 mg/dl) are relatively controlled, but the bedtime level (185 mg/dl) suggests that the evening insulin dose might not be adequate to control overnight glucose levels. However, the key issue here seems to be the **duration of action** of the morning insulin not adequately covering the pre-lunch period. Adjusting the insulin regimen to increase the dose or modify the type of insulin to provide better coverage during the day would be necessary.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests decreasing the morning dose, which would likely worsen the pre-lunch hyperglycemia.
- **Option B:** This option suggests increasing the evening dose. While the bedtime glucose level is elevated, the primary issue seems to be the pre-lunch hyperglycemia, not the bedtime or before dinner levels directly.
- **Option C:** This option suggests increasing the morning dose of insulin. Given the patient's pre-lunch hyperglycemia, this could help by providing more insulin coverage during the morning and into the lunch period.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **NPH insulin** has an onset of action within 2-4 hours, peaks in 4-12 hours, and lasts about 12-18 hours. **Regular insulin** has a quicker onset but a shorter duration of action. When adjusting insulin regimens, consider the timing of glucose elevations and the pharmacokinetics of the insulin types being used.

## **Correct Answer:** C. Increase the morning dose of NPH and Regular insulin.