Final answer:
NPH insulin, also known as Humulin N, should be given with food within 30 minutes after administration to prevent hypoglycemia and ensure the insulin is effective when blood glucose levels rise from food intake.
Step-by-step explanation:
When administering NPH (Humulin N) insulin, it is important to time the food intake correctly due to the pharmacokinetics of this medication. NPH insulin has an onset of action that typically occurs in 1 to 2 hours after injection, reaches a peak in 4-12 hours, and has a duration of about 12–18 hours. The aim is to match the peak action of the insulin with the rise in blood glucose that occurs after eating. Therefore, it is generally suggested to give food within 30 minutes after administration of NPH insulin to ensure that the insulin will be effective when the blood glucose levels start to rise after the meal. This timing helps prevent hypoglycemia (low blood sugar) that can occur if the insulin action peaks before the food has increased the blood glucose levels.