Interview: Treatment of diabetes with insulin
Today we have an interview with a Canadian university professor Laurentian University and the theme will be – treatment of diabetes with insulin. Let’s talk about how to do injections, how often, and so on. Read more in the interview.
My practice nurse would like me to try a new long-acting insulin but tells me there are two options and she is not sure which one to use in my case. Could you please elaborate?
There are two long-acting analogue insulins: detemir (Levemir) and glargine (Lantus). They are both ‘designer’ insulins which are intended to last for up to 24 hours. There is not much to choose between them. Detemir is probably more consistent in its action and glargine has a slightly longer duration of action. This means that as a background insulin, you are more likely to have to take detemir twice a day – usually before breakfast and at bedtime. Glargine is in a slightly acid solution and some people complain that it stings a little when injected.
For the past four years, I have used Actrapid insulin before meals and Insu-latard at bedtime. I’ve recently been changed to NovoRapid as mealtime insulin and I’m not very happy. My control has got worse and I seem to need much larger doses of NovoRapid compared with the dose of Actrapid. It is very disheartening as I was told the new insulin would make life easier.
This is a common problem with changing to NovoRapid and there is a simple explanation. It concerns the need for background insulin 24 hours a day. Actrapid is a longer-acting insulin than NovoRapid and usually lasts from one meal to the next. Thus Actrapid before a meal provides the surge of insulin for the meal but once you are back in the basal (unfed) state, the activity of Actrapid persists, acting as background insulin until your next insulin injection. This has the downside of putting you at risk of a hypo before your next meal and increasing the need for snacks between meals. NovoRapid (exactly like Humalog) is designed to act more rapidly and wear off sooner than Actrapid. The risk of hypo is reduced but now there are times between meals when you have no background insulin.
There are two solutions to this problem. One is to take an extra injection of Insulatard before breakfast. This would last throughout the day until your second injection of Insulatard at bedtime. The other option is to change to a longer-acting analogue such as glargine or detemir. These last for up to 24 hours, unlike Insulatard which only has a duration of 16 hours. Whoever replaced your Actrapid with NovoRapid should have predicted this need to change your background insulin.
What should I do if I suddenly realise I have missed an injection?
It is quite easy to forget to give yourself an injection or – even worse – to be unable to remember whether or not you have had your injection. If this happens you should measure your blood glucose level to help you decide what to do next.
If your blood glucose is high (more than 10 mmol/L) you probably did forget your injection and you should have some short-acting insulin as soon as possible. The dose depends on how close you are to the next injection time. If your blood glucose is normal or low (7 mmol/L or less) you probably did have your injection even if you have forgotten doing it. It would be safest to check your blood glucose again before your next meal and, if it is high, to have an extra dose of short-acting insulin.
I have just left hospital after a heart attack. I was found to have diabetes, which came as an extra bit of bad news. I have been sent home on four injections of insulin a day, but have been told that I may be able to stop insulin after three months. Why was insulin necessary?
In general, once people start insulin, they need to continue this for the rest of their lives. However, you are probably an exception to this rule. A study published in 1995 showed that anyone who had a heart attack and a raised blood sugar made a much better recovery if they were treated immediately with insulin while in the coronary care unit and for three months after leaving hospital. This applied to people who were already known to have diabetes and those (like yourself) who were previously undiagnosed. Those patients who received the intensive insulin treatment both in hospital and for another three months had a much smaller risk of having another heart attack over the next 12 months. The exact reason why insulin provides this long-term protection is not understood, but the results of the study have to be taken seriously and acted upon.
In your case it is likely that you will be seen by a diabetes specialist three months after leaving hospital and it should then be possible to stop insulin and try a different treatment for your diabetes. Some patients in your position find that they get on extremely well with insulin and when offered the option of stopping it, they choose to continue on the grounds that at some stage in the future, they are likely to need insulin again and they cannot see the point of stopping it for a few years.
Is my insulin requirement likely to vary at different times of the year because of the weather?
Several people have remarked that their dose of insulin needs to be altered in very hot weather: some need to give themselves more insulin and others less. This is probably because people react in different ways to a heatwave. There is a tendency to eat less and take less exercise in tropical conditions. However, because blood flow to the skin is increased in warm temperatures, this could speed up the absorption of the injected insulin and mean that a given dose will not last as long. Everyone is different and you will have to find out for yourself how hot weather affects your own blood glucose.
If my insulin requirements decrease over the years, does this mean that the pancreas has gradually started to produce more natural insulin than when I was younger?
No. It is most unlikely that after many years of diabetes your pancreas will start to produce natural insulin. However, this reduction in dose in older people is well recognised. It could be that you were having more insulin than you really needed in the past. Since the introduction of blood glucose measurement many people are found to be having too much insulin, or sometimes too much at one time of the day and not enough at another. Other possible explanations for older people needing less insulin are that they eat less food, they become thinner, they have a different exercise pattern, and there may be hormonal changes.
What is an insulin pen, and what are the advantages of using one?
An insulin pen consists of a cartridge of insulin inside a case like a fountain pen which is used with a special disposable needle. After dialling the required number of units of insulin and inserting the needle into the skin, you press the plunger or button and the pen will release the correct dose of insulin. There are also pens which have insulin built in and these are known as prefilled pens, preloaded or disposable pens. All cartridges and prefilled pens now contain 300 units of insulin and are likely to last several days before needing to be changed. In general the pens are only compatible with insulin cartridges from the same manufacturer.
The great advantage of insulin pens is that they are easier to use than syringe and needle and more convenient. It is simple to give an injection away from home, for example at work, in a restaurant or when travelling. If your eyesight is not good you may find the dial-a-dose clicking sound helps to reassure you that you have dialled up the correct dose. Some pens give a distinct click with each unit or two units dialled.
If you suffer from arthritis or nerve damage in your hands you are likelier to find a pen easier to use than drawing up insulin in a conventional syringe. All these pens rely on ordinary finger pressure for the injection, that is, they are not automatic injectors, but some may be easier than others. For example, the InnoLet prefilled pen has been especially designed to have a distinctive click and needs mild finger pressure to inject the insulin.
If you find it difficult to inject your insulin because of fear of needles, but would like to use a pen, Novo Nordisk has introduced the PenMate which hides the needle from view when the injection is given. The PenMate can be obtained on prescription.
Several makes of pen are available and your healthcare professional will show you the current models. Insulin pens are now available on prescription except for the OptiClik Pen which can be obtained from your nurse. In an urgent situation most pens are available from your hospital diabetic clinic. It may help to have two pens so one can be used as a back-up in case of breakage or loss.
I have been told I need four injections a day. I am worried that I might get the insulins mixed up. What can I do to prevent this?
Many people now take three, four or five insulin injections a day and this will mean using two or even three different types of insulin. This is known as a ‘basal bolus’ or multiple injection regimen. The ‘basal’ insulin is the long-acting background insulin and the ‘bolus’ dose is taken when a meal or a large snack is eaten. Some people may take a fixed mixture of insulin in the morning, a fast-acting insulin with their evening meal and a background insulin at bedtime.
The idea of using a multiple injection regimen is to try to mimic the normal insulin secretion of the pancreas, by giving small doses of short-acting insulin to cover meals and a longer-acting insulin once a day to act as a background insulin. The insulin pen was originally developed to make it more convenient for people to inject four times a day. We agree that it can be confusing if you are taking two or three insulins but most pens are available in different colours to help distinguish the different insulins being used. If you are using prefilled pens, these are already colour-coded.
Interviews taken with the participation of Canadian Health Care Mall – www.canadianhealthcaremalll.com