Insulin: Types & Regimens

Key points

• Rapid-acting analogues (aspart, lispro, glulisine): onset about 15 min, peak about 1 h, last 2-5 h — given with meals.
• Short-acting soluble/regular human insulin (e.g. Actrapid): onset about 30 min, peak 2-4 h — given 30 min before meals; also used in IV infusions (DKA/HHS, variable-rate insulin).
• Intermediate-acting isophane/NPH insulin: onset 1-2 h, peak 4-8 h, lasts up to about 16 h.
• Long-acting analogues (glargine, detemir, degludec): a flat ~24 h (degludec longer) profile — used as basal insulin.
• Regimens: basal-bolus (long-acting basal + rapid-acting with meals) is the most flexible and preferred in type 1 diabetes; twice-daily biphasic/premixed mixtures (e.g. 30% rapid + 70% intermediate); once-daily basal insulin is often added to oral agents in type 2 diabetes.