Which statement best explains why morning NPH insulin can cause hypoglycemia in the afternoon?

Which statement best explains why morning NPH insulin can cause hypoglycemia in the afternoon?

• A. NPH insulin has a peak action in the afternoon after morning administration
• B. NPH insulin peaks immediately after injection
• C. NPH insulin has its peak several days after injection
• D. NPH insulin does not cause hypoglycemia

Answer: (A)

Understanding how NPH insulin works helps explain why morning injections can cause afternoon low blood sugar. NPH is an intermediate-acting insulin whose absorption is slower, so its effects don’t show up right away. It typically begins working about 1–2 hours after injection, peaks roughly 6–8 hours later, and lasts about 12–18 hours. So when given in the morning, its peak activity falls in the afternoon, increasing the risk of hypoglycemia if meals aren’t aligned or if activity changes. The other ideas aren’t consistent with how NPH behaves: it does not peak immediately after injection, it does not peak days later, and it can indeed cause hypoglycemia.

Understanding how NPH insulin works helps explain why morning injections can cause afternoon low blood sugar. NPH is an intermediate-acting insulin whose absorption is slower, so its effects don’t show up right away. It typically begins working about 1–2 hours after injection, peaks roughly 6–8 hours later, and lasts about 12–18 hours. So when given in the morning, its peak activity falls in the afternoon, increasing the risk of hypoglycemia if meals aren’t aligned or if activity changes. The other ideas aren’t consistent with how NPH behaves: it does not peak immediately after injection, it does not peak days later, and it can indeed cause hypoglycemia.