www.diabeticretinopathy.org.uk

General

Insulin types and amount 

David Kinshuck

 

 

 

Insulin & DAFNE

DAFNE uses human genetically engineered insulin. There are other insulins, such as pork and beef, but here we concentrate on the insulins used in the DAFNE program.

 

How much insulin do you need?

In type 1 diabetes, most people need a total  of 0.5 - 0.8 units of insulin per kilogram of body weight each day. Roughly half this insulin is needed for food intake, and half is the basal  rate.
In DAFNE half is therefore taken as long-acting insulin and this is divided into two injections of Levemir (detemir) insulin. One injection when you get up in the morning, and the other in the evening at bedtime. For most people, this is about 24 units in 24 hours.

The amount of background insulin does not depend on what you eat, and the dose should be low enough to allow you to miss meals without the risk of low glucose (a hypo), whilst still keeping the glucose levels within the target range.

The remainder of the total daily dose is taken at meal times, as a quick acting insulin. Sometimes these are given as insulin mixtures, but not in the DAFNE program.

 

Quick-acting insulin

The quick-acting (QA) part of the total daily dose is taken at meal times, matched to the carbohydrate. Think of this as food-related insulin that is taken immediately before food. Generally, you need 1-3 units of insulin per carbohydrate portion (CP) at breakfast, and between 1-2 units QA insulin per CP at other meals. These ratio of QA : CP may vary depending on the time of day. Detail

Everyone has different insulin needs...you learn how to calculate your own requirements on the DAFNE course.

The quick acting insulins that are now popular in the UK are

They start to work 15 minutes after the injections, and continue to lower glucose levels for 2-5 hours.

 

Long-acting (background) insulin

NICE 15  prefers twice daily Levemir (detemir). Levemir (detemir) insulin has a peak action at 9-12 hours, but still has a little action at 24 hours.

Many type 1 patients use Lantus (Glargine) insulin...Lantus is more long-acting.

 

Insulin injections

For example

  1. a carbohydrate portion is an egg-size potato, 10 gm carbohydrate
  2. this increases glucose level 2 mmol/g
  3. so 4 egg-size potatoes = 40 gm carbohydrate
  4. what is you insulin need per unit of carbohydrate? your nurse will advise, but an average will be 1.5 units of insulin for each carbohydrate portion.
  5. This ratio (eg 1.5) will de different at breakfast time, lunch time etc, but is usually similar for each lunch. (stress, exercise, illness, also affect this level; so does obesity)
  6. so if you eat 4 potatoes you will need 6 units of insulin.
  7. But then you need to take into account the blood glucose level when tested just before the meal....10gm of glucose may increase glucose level 2mmol/g. So if your pre-meal glucose level is 10.4, and you are going to eat 4 potatoes, you will need
    • 6 units of insulin for the potatoes
    • 3 units extra to drop the insulin 4mmol/g to 6.4 (from 10.4)
    • =9units