Which describes onset times for rapid-acting, short-acting, and long-acting insulin preparations?

• A. Rapid-acting 60-90 min; Short-acting 1-2 hours; Long-acting once daily.
• B. Rapid-acting 15-30 min before meals; Short-acting 30-60 min; Long-acting once daily, no pronounced peak.
• C. Rapid-acting 10-15 min; Short-acting 5-10 min; Long-acting 2-4 hours.
• D. Rapid-acting 2-4 hours; Short-acting 1-2 hours; Long-acting 8-12 hours.

Answer: (B)

Onset times describe when insulin starts to work after you inject it, which is key for matching insulin action to meals and daily background needs. Rapid-acting insulins begin to work within minutes and are typically given right before meals, around 15–30 minutes prior. Short-acting (regular) insulin takes longer to start, usually 30–60 minutes before a meal. Long-acting insulins have a gradual onset, about 1–2 hours after injection, and provide a steady, peakless effect over roughly 24 hours for basal coverage. The described pattern—rapid-acting 15–30 minutes before meals, short-acting 30–60 minutes before meals, long-acting once daily with no pronounced peak—best fits these pharmacokinetic profiles.