Mine was on butagran (that looks wrong ) for a good few years, the last months on two a day. He hadn’t had ulcers but had no problem on it.
Is it slightly coated as well with something? I just know when I lent some to a friend who’d ran out of normal bute she pointed out it’s in a 5g packet but contains the same amount of bute as a regular 1g bute sachet.
Butagran has a butter vanilla flavouring so might be that. Fron what I can find danilon has a less chance of ulcers. It would help if the vet actually rang back!