A patient with IDDM injects a mixture of NPH insulin and crystalline zinc (Regular) insulin before breakfast (at 7 AM) and before dinner (at 8 PM) each day. She reports the following average self monitored RBS for the past week.

This patient should increase both the 7 AM (pre break fast) and pre-dinner doses of crystalline zinc (regular) insulin. The dosage of rapid-acting regular insulin administered before breakfast and dinner can be adjusted on the basis of the pre-lunch and bedtime blood glucose values, because the peak effect of the regular insulin injections will occur at these times. Because both the pre-lunch and the bedtime glucose levels are significantly elevated, both doses of regular insulin should be increased. The dosage of neutral protamine Hagedorn (NPH) insulin can be monitored using the pre-dinner and pre-breakfast blood glucose determinations, because the morning and evening NPH injections will have their peak effect at these times. Because both pre-dinner and pre-break­fast levels are normal, there is no need to adjust NPH dosage.