A patient with diabetes mellitus is on regular insulin, which is administered in the morning at 9 AM, what time will the regular insulin reach its peak?

Appeared in: NORCET 3 - 2022 (Shift-1)

Explanation

Regular insulin is a short-acting insulin with a peak effect occurring 2 to 4 hours after subcutaneous administration.
Given that the insulin was administered at 9:00 AM, the peak effect is expected to occur between 11:00 AM and 1:00 PM.
Out of the given options, 12:00 PM is the only time that falls comfortably within this 2-4 hour peak window.
This peak time is when the patient is at the highest risk for hypoglycemia, so monitoring and meal planning are critical.

Option A: 10:30 AM is only 1.5 hours after the 9:00 AM administration. This time falls within the onset period of regular insulin, not its peak.
Option C: 4:00 PM is 7 hours after the 9:00 AM administration. This is well past the 2-4 hour peak window for regular insulin and is near the end of its duration of action.
Option D: While 11:00 AM is 2 hours post-administration and marks the beginning of the 2-4 hour peak window, 12:00 PM is more centrally located within this range, making it a better representation of the peak effect.

Visual 1: Graph - A line graph comparing the blood concentration curves of rapid, short, intermediate, and long-acting insulins over a 24-hour period. This helps visualize the differences in onset, peak, and duration.
Visual 2: Infographic - A chart summarizing the different types of insulin with their brand names, action profiles (onset, peak, duration), and key nursing considerations for each.

Clinical Relevance

Nursing practice connection: Use the key finding related to Pharmacokinetics of Insulin to guide bedside assessment, documentation, and the next nursing action.
Understanding insulin peak times is a fundamental patient safety competency for nurses. Administering insulin without coordinating it with meals can lead to severe hypoglycemia.
The nurse's primary role is to administer insulin correctly, monitor for adverse effects (especially hypoglycemia at peak times), and educate the patient on self-management, including meal timing and recognizing low blood sugar symptoms.
What if the patient was on NPH insulin instead of regular insulin? If NPH was given at 9 AM, the peak would be between 1 PM and 9 PM, significantly changing the time of highest hypoglycemia risk.

How to Approach the Question

First, identify the key information in the question: the type of insulin ('regular insulin') and the administration time ('9 AM').
Next, recall the pharmacokinetic properties of the specified insulin. For regular (short-acting) insulin, the crucial fact is its peak action time: 2-4 hours.
Perform a simple calculation: Add the peak time range (2 to 4 hours) to the administration time (9:00 AM). This gives you a target window of 11:00 AM to 1:00 PM.
Finally, evaluate the given options and select the one that falls within the calculated peak window. In this case, 12:00 PM is the best fit.

Concept Tested & Keywords

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Practise the full NORCET 3 - 2022 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.