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General

Insulin Mixtures: twice daily 'mixed' insulin

David Kinshuck

 

 

This page is really out of date (2016), as there are many new types of insuloin mixtures.

 

 

 

 

 

 

You cannot adjust this insulin easily. It is suitable for elderly people or if you have other medical problems that make taking insulin difficult. Some people decide they want two injections a day as they are not will to have 4 injections a day.
It is not ideal if you are working and trying to seek good control to help your eyes, as it is hard to get good control under these circumstances. See starting insulin (multiple insulin injections prevent retinopathy).

However, unless you are very frail, is still important to test your sugar. Basic insulin rules apply. For instance, you still need insulin if you are ill, and usually need more if you have an infection. If you cannot eat because you are sick for example, you need to consult your doctor within a few hours, but you still need insulin.

If you exercise more than usual you may get a hypo. Similarly if you go without food, you may develop a hypo, so test as a precaution. If you eat an unusually big meal expect to have a high sugar (test to confirm).

If you are a type 2 diabetic and previously used tablets, you may put weight on using insulin, so you need plenty of exercise, and usually a strict diet. If you put weight on you will need even more insulin, and are likely to enter a type of vicious circle of increasing insulin and weight. Often metformin may help if you are overweight, as this helps to reduce the amount of weight gained.

It is usually appropriate for you to make minor adjustments to your insulin dose, depending on your blood sugars. See the table below.   Complex insulin regimes do lead to better glucose control, fewer hypos, and better weight control than twice daily insulin (NEJM 2009). See.

 

Adjusting the insulin dose with twice daily insulin mixtures

 

How to adjust premixed twice daily insulin, but everyone is slightly different Remember the obvious causes of fluctuating sugar: for instance, have you eaten twice as much as usual? has your

 

Blood glucose level before evening meal Adjustment needed to breakfast dose of insulin
4.0-7.0 mmol/l No change
7.1-9.0 mmol/l Increase by 2 units
Above 9.0 mmol/l Increase by 4 units
Blood glucose level before breakfast Adjustment needed to evening meal dose of insulin
4.0-7.0 mmol/l No change
7.1- 9.0 mmol/l Increase by 2 units
Above 9.0 mmol/l Increase by 4 units

 

Trouble shooting insulin mixtures twice daily

Let us consider some obvious situations.

  1. If your sugars remain controlled, that is 5-6 mmol/l before meals, and less than 8 two hours after a meal, you are likely to be controlled. Good control can be confirmed by the next HbA1c level you have at your doctor's.
  2. insulin been out in the sun all day?
  3. If you have an infection, aside from seeing your doctor to see if you need antibiotics, and your sugars are 10-12 mmol/l, increase your insulin dose 2 units (see box immediately above).
  4. If you are going to start regular exercise, consider reducing your insulin before your exercise 2-4 units.
  5. If your sugars are high 2 hours after a meal (say 10 mmol/l), but too low before a meal (say 4 mmol/l), it becomes difficult to adjust your insulin. Here a different insulin mixture, or if you are happy to test, a different regime such as basal bolus may be appropriate. Thus if you sugars are very variable you usually need a different type of insulin, so ask your nurse. There are different types of insulin mixtures if you still need to use a twice daily regime.
  6. If you work and a very hard job Monday to Friday, and take it easy at weekends, you may need more insulin at weekends.
  7. If your HbA1c is higher than 7.5% you control is not ideal. If you have been diabetic 15-20 years, the best you may be able to achieve with this regime is an HbA1c 8%.
  8. The chart above helps you 'fine tune' your insulin. But remember, sometimes an HbA1c lower than 8% is not possible with a twice daily insulin mixture, and you may need to change to the basal bolus regime.
  9. If you start a diet and start to eat less and lose weight, you will start to need less insulin. Insulin dose is directly related to exercise (reduces insulin need) and weight (increases need).