Peak and duration of regular insulin?

• A. Peak 1-5 hrs; Duration 3-8 hrs
• B. Peak 0-1 hr; Duration 2-3 hrs
• C. Peak 6-12 hrs; Duration 12-24 hrs
• D. Peak 3-4 hrs; Duration 4-6 hrs

Answer: (A)

Regular insulin is a short-acting insulin whose effect starts within about 30 to 60 minutes after injection, with a peak in the range of roughly 2 to 4 hours and a total duration of about 6 to 8 hours, though there is individual variability. The option that best matches this pattern is one that lists a peak around 1 to 5 hours and a duration around 3 to 8 hours, capturing the typical time frame and allowing for variability between patients. The other patterns imply pharmacokinetic profiles that don’t fit regular insulin: either too early onset with too short a duration, or a much later peak with a much longer duration, or a narrow window that doesn’t align with how regular insulin behaves.