Insulin Types and Timing

By VeriScorePrep Team · 6 min

Insulin differs by onset, peak, and duration, and matching timing to meals and activity is essential to prevent hypoglycemia.

The four categories

• Rapid-acting (lispro, aspart, glulisine): onset ~15 min, peak ~1 hour, duration ~3–4 hours. Give 15 minutes before meals.
• Short-acting (regular): onset ~30–60 min, peak ~2–3 hours, duration ~5–8 hours. Give 30 minutes before meals. The only insulin approved for IV use.
• Intermediate-acting (NPH): onset ~1–2 hours, peak ~4–10 hours, duration ~10–18 hours. Cloudy; resuspend by gentle rolling — never shake.
• Long-acting (glargine, detemir): onset ~1–2 hours, no pronounced peak, duration ~24 hours. Clear; do not mix with other insulins in the same syringe (unless specifically directed).

Mixing

When combining NPH and regular in one syringe, inject air into NPH first, then regular; withdraw regular (clear) first, then NPH (cloudy). Roll NPH gently — never shake it.

Hypoglycemia teaching

If blood glucose is below 70 mg/dL, follow the 15-15 rule: 15 g of fast-acting carbohydrate, recheck in 15 minutes, repeat if still low. Severe hypoglycemia with unconsciousness requires glucagon or IV dextrose.