Hi
There are 3 different analogue insulins that I know of. As well as Novorapid, there is Humalog and Apidra. All the 3 big insulin companies make there own version, and all have different profiles.
There is a reaction profile for Novorapid on this site
Data Sheet
However, reaction profiles are nothing more than a guide. Everyone reacts differently and it's not until you give it a go that you'll know for sure.
In me (and quite a few other people) Novorapid lasts in total 4-5 hours. It is supposed to start acting after 10 mins or so. Also it seemed to be that 25% of the dose got used per hour, and it was pretty much all gone by the time 4 hours were up. This made it a very reliable insulin, though it did mean that I would often have a fairly hefty peak at hour 2. In the morning, this would be pretty unpleasant.
For this reason, I switched to Apidra a few weeks ago. Apidra is the first insulin with me where the manufacturer's claimed swift onset is actually completely true. It really does hit like a train. I have now stopped trying to second guess it and pre-inject as a 20 min before breakfast injection last week with a high (for me) pre meal reading of 7.5 (135) resulting in me going very low indeed 20 mins after eating. My carb ration was spot on, it was purely the bell curve that got me!
If you do change to Novorapid (or anything else) take it steady for a day or two and the usual good practice of having fast acting carbs with you is doubly important. Of the three, Apidra claims to be fastest (though I've seen some people on here that it made no difference for). Next is supposed to be Novorapid, then Humalog. But these two are pretty close, and for some folks Humalog is quicker than Novorapid.
Gary
