Hi and welcome, since i see this is your first post on the forum.
When you say that Novo(not so)Rapid has stopped working for you, can you explain what you mean? Is it just that it takes a long time to kick in, so your prebolus time is becoming ridiculously long or that you are needing progressively larger doses.... or something else?
I switched from NR to Fiasp about 3 years ago as I needed 75 mins prebolus time at breakfast most days with NR which was just not practical and half an hour at other times of the day. I found swapping to Fiasp extremely frustrating and after 3 months of tearing my hair out, I went back to NR for 6 months and then gave Fiasp another trial. If I hadn't promised myself I would stick at it for a year that second time, I would have quit after 3 months again as it really wasn't a simple straightforward swap.
In my opinion, Fiasp is quirky and it takes time to understand and learn to live with those quirks or at least decide if those quirks are better than going back to sluggish but dependable NR.
My experience with Fiasp is similar to
@helli's but with some differences. I believe she is more sensitive to insulin than me, so even if my levels are low 4s, I still need to inject before eating, but I have a fast digestive system and slow insulin absorption. Once my levels get above 10, Fiasp seems to turn to water and I can easily need twice as much insulin as I would otherwise, sometimes more and I have to wait a long time for it to kick in. The key for me was to be very proactive about keeping levels below 10 and my Libre high alarm is set at 9.2 to help with that and for me, once my levels get above 10 I usually have to stack corrections sometimes with as little as 30 mins between them if levels continue to rise despite the previous correction. I am not advocating you do this as it is frowned upon and can be dangerous because you risk going hypo by stacking corrections, but this is what works for me and probably less dangerous now that we have CGM to monitor our levels. Basically I had to learn to be heavy handed and break the rules to make Fiasp work for me. I am now 3 years down the line with it and whilst it isn't ideal, I would be reluctant to change again or try something new and I can consistently achieve high 80s-low 90s TIR with it and Levemir... although the Levemir plays a big part in that achievement. I absolutely love my Levemir. I can make Fiasp work for me but it's a long way off perfect. The disruption of changing is what makes me stick with it, not because I particularly like it, but it is a marginal improvement on NR.
Hope our experiences with it help you to decide if it is worth trying for you, but knowing the issues you are having with NR will help us suggest if Fiasp is likely to be an improvement.
