A newly diagnosed diabetes mellitus client self-injected NPH insulin at 7:30 am. The nurse reviews the time frames for peak insulin action. The client should be especially watchful for hypoglycemia between which time frame?

• A. 7:30 am and 9:30 am
• B. 1:30 pm and 7:30 pm
• C. 8:30 pm and 12:00 am
• D. 2:30 am and 4:30 am

Answer: (B)

NPH insulin is an intermediate-acting insulin with a peak several hours after injection. After a morning dose given at 7:30 am, the peak action generally occurs about 6–14 hours later. That places the highest risk for hypoglycemia from roughly 1:30 pm to 7:30 pm. During this window, insulin activity is strongest, so glucose can drop more rapidly if too much insulin is present or if meals and snacks don’t align with the action of the dose. Therefore, the client should be especially watchful for hypoglycemia in that afternoon to early evening period, when monitoring and having quick sources of glucose are important. Other time frames either come earlier, before the peak, or after the peak period, where the risk is lower.