Expansion
Rapid, short, intermediate and long acting, matched to basal and prandial needs
Mnemonic
Group by how fast and how long:
- Rapid acting analogues - lispro, aspart, glulisine. Onset 10 to 20 minutes, last 3 to 5 hours. Given with meals
- Short acting (soluble, human) - Actrapid. Onset 30 minutes, lasts 8 hours. The one used in variable rate intravenous infusions
- Intermediate - isophane (NPH). Lasts 12 to 18 hours
- Long acting analogues - glargine, detemir, degludec. Flat, peakless, 24 hours or more
“Rapid with the meal, long once a day”, which is the logic of the basal bolus regimen: a long acting background plus a rapid acting dose with each meal.
Only soluble human insulin is given intravenously, because the analogues offer no advantage when infused.
Regimens: basal bolus for type 1 and for flexibility; twice daily mixed for a fixed routine; once daily long acting added to oral agents in type 2.
Never omit basal insulin in type 1 diabetes, even when the patient is nil by mouth, because doing so precipitates ketoacidosis regardless of the glucose.
Expansion
| Class | Onset | Peak | Duration | Examples |
|---|---|---|---|---|
| Rapid analogue | 10 to 20 min | 1 h | 3 to 5 h | Lispro, aspart, glulisine |
| Short (soluble) | 30 min | 2 to 3 h | 6 to 8 h | Actrapid |
| Intermediate | 1 to 2 h | 4 to 8 h | 12 to 16 h | Isophane (NPH) |
| Long analogue | 1 to 2 h | Flat | 20 to 24 h+ | Glargine, detemir, degludec |
Regimens
- Basal bolus: long acting once daily plus rapid acting with meals. Most flexible and closest to physiology
- Twice daily mixed: fewer injections but requires fixed meal timing
- Continuous subcutaneous infusion (pump): rapid-acting insulin only, with a programmable basal rate
Two overnight phenomena worth distinguishing:
- Dawn phenomenon: an early morning rise in glucose from the normal surge of growth hormone and cortisol. Managed by increasing basal insulin
- Somogyi effect: rebound hyperglycaemia after nocturnal hypoglycaemia. Managed by reducing it. Continuous glucose monitoring distinguishes them