novo-rapid insulin duration

by my understanding the above quick-acting insulin has onset period of less than 15 minutes. a peak between 50 and 90 minutes and a duration of up to 5 hours. not trying to be to technical is it known in percentage terms how this time period is broken down ie how much insulin is still to be used after a meal which was consumed say 4 hours ago and 10 units of the above insulin was used in total? why i ask is that as a bus driver i work various shift patterns and on some occassions will have another meal break within the total effective period of this insulin which in turn would i suspect have a bearing on my next insulin dosage to combat my next meal/snack.obviously if i take to much and go to low i.e below 4mll i would be unable to drive.iam curious if anyone could shed any light on this matter or whether i am looking to deeply into the above.any thoughts would be much appreciated

cheers paulj

Hi Paul,

just another bumbling graduate rather than a HCP here but I think it's pretty hard to give set guidelines on how much of your insulin is spent and how much is still working. as a VERY rough guide there is the graph in the DAFNE handbook which I suspect you have seen already as some of what you said is almost a direct quote from it.



As a rough guide though you can see by hour 3 there is very little life left in it and by hour 4 you can almost assume it's all gone as a general rule. There are however a number of factors that can change how quickly the insulin will work, some are down to your physiology, some are environmental so that can only ever be taken as a rough guide and certain not something to do precision maths with to keep you just above 4mmols

Personally I try to keep 4 hours between meals but if I had a late breakfast and can't push back lunch so there has only been 2 hours between the meals and I test and find I'm high, I choose to trust that I gave enough insulin earlier and it will bring me back down given time to finish working and take only the insulin that my lunch dictates (i.e. no correction)

If I were you then should I find myself eating again less than 4 hours after my last shot I'd test, eat & inject without correction for any highs (obviously correct if there is a low) and then test again in 4-5 hours time and correct if required then. Also should you find yourself a bit close to the 4 mark the quickest way to get your levels up is with a sugary liquid, personally I go with a can of coke which I find hits the blood in under 5 mins.

Not sure that's quite the advice you were looking for but I think there are probably a few to many unknowns to do exactly what you hoped to do, that said after a few months you may find you get a better understanding of how you personally react to the insulins you use and you may be able to refine things slightly better.

Another thing that may be worth while to you is a continuous glucose monitor, which is a test meter you leave attached to you and tests every few minutes. Most have the option to then alert you if you're going low so you can prevent yourself going under 4mmols. I'm not sure if these are available on the NHS or not though so there may need to be an element of self funding on your part if this was something you wanted to look into. certainly asking you diabetic healthcare team what your options are with it though, they do tend to be expensive though.

Great explanation by travler there.......

If you do have to eat within the 4 - 5 hours you would simply take insulin for the meal without considering a correction, so you don't really need to test your blood sugar at this intermediate meal/snack....

however, there are now several meters on the market: Accu Check combo, InsulinX, which have a bolus wizard and on board insulin calculator on them.......these can tell you how much insulin is actually left in your system and whether or not you need some correction or not......

provided your carb count is correct and the insulin action is behaving as you would expect, there will never be a need to correct mid meal, as the wizard should work out that the correction you need for the 'mid meal' snack is in fact what is left in your system at that time......

Interesting, I didn't know that there were meters that did that, I'd personally take what they say with a little suspicion though as the real world data compared to the graph I posted is roughly similar but no where near as smooth and perfectly predictable. It's the kind of feature I'd expect to come with a massive disclaimer and be more intended as a gimmicky little feature than real world tool.

If in doubt (especially when operating a car, bike or bus) always safer to run high. I imaginr it was hard getting the ok to drive a bus as it is so you don't want to be giving anyone any reason to want to revoke your license by start hypoing

Obviously these meters, and all the insulin pumps that provide on board insulin calculations, require an initial set up where you input the duration of your bolus/QA insulin......so they are real world tools in that sense, they are used and with a high reliability......have a look online at these meters.....you could probably get one free to try out......

You would need to work out the insulin duration for each individual by testing, but I personally was put on a 4 hour duration when beginning with the pump, I have now increased that to 4:30 hours.....

its pretty reliable, but as I mentioned before, if the carb count is correct and the duration has been fine tuned, you shouldn't ever need to give additional correction when eating in between the usual meal times....

Hmm sounds impressive.

I'll pass on trying it out myself as I've got meters coming out of my ears. Last time I asked Bayer for a contour USB they sent me two of them plus a non USB model so I could almost have a different meter for every room in the house & they are asking me if I want the new latest model now. But it sounds like it has had a lot more thought put into it than I initially gave it credit for.

I'll add it to my reading to do list