Insulin types and regimens: basal-bolus, mixed and sliding scale for UKMLA
RezzyHey! Diving into the world of insulin for the UKMLA? It's a classic AKT topic. Understanding these regimens is basically a rite of passage for any final year student, especially since you'll be the one prescribing them on the wards soon!
Let's start by looking at the different "flavors" of insulin we have available in the UK. I've put together a quick comparison table to help you keep the onsets and durations straight.
| Type | Examples (UK Brand Names) | Onset | Duration | Clinical Use |
|---|---|---|---|---|
| Rapid-acting | Novorapid (Aspart), Humalog (Lispro) | 10-20 mins | 3-5 hours | Bolus (mealtime) |
| Short-acting | Actrapid, Humulin S (Soluble) | 30-60 mins | 5-8 hours | IV infusions (VRII/DKA) |
| Intermediate | Insulatard, Humulin I (NPH) | 1-2 hours | 12-16 hours | Basal (often BD) |
| Long-acting | Lantus (Glargine), Levemir (Detemir) | 1-2 hours | 24 hours | Basal (usually OD) |
| Ultra-long | Tresiba (Degludec) | 30-90 mins | >42 hours | Basal |
Now that we've got the types down, let's talk about how we actually use them in practice. For the UKMLA, you need to know which regimen fits which patient profile.
1. Basal-Bolus (Multiple Daily Injections - MDI)
This is the gold standard for Type 1 Diabetes (T1DM) because it mimics the natural pancreas.
- Basal: One or two injections of long-acting insulin (e.g., Lantus or Levemir) to keep blood sugar stable between meals and overnight.
- Bolus: A rapid-acting insulin (e.g., Novorapid) taken before each meal.
- High-Yield Fact: NICE NG17 recommends twice-daily Levemir as the first-line basal insulin for T1DM.
2. Mixed (Biphasic) Insulin
These are pre-mixed pens containing a percentage of rapid/short-acting and intermediate-acting insulin (e.g., Novomix 30 is 30% rapid, 70% intermediate).
- Regimen: Usually taken twice daily (BD) with breakfast and dinner.
- Who gets it?: Often used in Type 2 Diabetes (T2DM) or for patients who find the basal-bolus regimen too complex (e.g., elderly patients or those with dexterity issues).
3. Sliding Scale (Variable Rate Insulin Infusion - VRII)
You'll see this all over the hospital! It's an intravenous infusion of short-acting insulin (usually Actrapid).
- When to use: When a patient is NPO (nil by mouth), having surgery, or is acutely unwell and their blood sugars are swinging wildly.
- The "Scale": The rate of the pump is adjusted hourly based on capillary blood glucose (CBG) readings.
- Crucial Point: ==Always continue the patient's long-acting basal insulin== even while they are on a sliding scale to prevent DKA when the pump is eventually stopped!
To help you visualize how these different regimens look throughout the day, I'll find a diagram of the insulin profiles.
Setting up chat...