Congrats! You’ve found a doctor who seems to have a clue about febuxostat.
You can’t cut Adenuric pills to 20mg precisly by yourself (or at least I wouldn’t know how to do it). Some pharmacists ought to be equipped for this but the service may be expensive and my rheuma said imprecise cuts are fine. You can cut to approximately 20mg without a pill cutter. Some (most?) pill cutters are actually worse than kitchen knives for this job. I use a tool not designed for cuting pills. You want a sharp, straight blade such as a razor blade and you want to be able to apply significant pressure.
About 1mg colchicine daily being consensual… well, I simply mean that this is a dose which would get recommended to you by different folks in many places. Like there’s a consensus on the matter.
The dosage to deal with acute attacks is another matter. I’ve been given different instructions, all different from the ones you’ve just been given.
Regardless, I agree you should be getting better after 3 days on 2mg colchicine. In fact it would be mighty disappointing if you weren’t better a good bit sooner.
The problem with not having a blood test done while on colchicine only is that you won’t be able to tell the effect of colchicine and febuxostat apart once you start the latter. Yes, both affect the liver. But then so do NSAIDs. And like I said, in my case NSAIDs are worse than colchicine. But you won’t know for sure which is worse in your case if you don’t get blood tests.
It would be a good idea to try some colchicine pills before going on febuxostat to see what side effects you get and understand how they work. But to get an idea of what 1mg daily over a month (or more) would do to your liver, you’d need to be taking the stuff every day for at least 10 days before getting a blood test I would think.
I forgot something else which may be dangerous liver-wise by the way: mushrooms. If gathering mushrooms is popular in your area, consider not eating that for a while. Professionally-grown mushrooms ought to be safer.
Now about going on febuxostat without taking a prophylactic daily… like I mentionned, that’s what I did and I got away with it. But your uric acid problem is a good bit worse than mine. It seems like it’d be risky in your case. But your experience with allopurinol ought to be the best guide as to what you can expect. Just be aware that febuxostat is very roughly 10 times stronger than allpurinol by weight. So even 20 mg daily would be a more brutal ULT than your initial allopurinol dose.