I'll be honest -- I don't know. From what I read, the recommendation is to stop Bexacat if the cat doesn't respond to conventional treatment for diarrhea. It doesn't sound like there was any suggestion from the vet regarding an intervention. You could try S. boulardii which is a probiotic that is great at stopping diarrhea. (You start with about 1/4 - 1/3 of a capsule and you can mix it into food.)
What I find challenging with Bexacat is that there are a lot of issues where it's recommended that you stop the medication. In a situation like you're running into, it's a weekend. You're likely not going to be able to talk to the vet that wrote the Rx until early next week. This means that your cat's diabetes is going untreated for several days. The risk is that if there's something other than the Bexacat that's causing a GI problem, there may be a chance that it's an infection or inflammation and it puts your cat at risk for ketones developing. Ketones are a major contraindication for using an SGLT-2 inhibitor. All of this is because this form of treatment is very new. We've not had many members who have been using Bexacat and there's just not a lot of research yet to guide decision making.
